using System;
using System.IO;
using System.Collections;
namespace BfEngine
{
	class LodePNG
	{
		/*
		LodePNG version 20210627

		Copyright (c) 2005-2021 Lode Vandevenne

		This software is provided 'as-is', without any express or implied
		warranty. In no event will the authors be held liable for any damages
		arising from the use of this software.

		Permission is granted to anyone to use this software for any purpose,
		including commercial applications, and to alter it and redistribute it
		freely, subject to the following restrictions:

		    1. The origin of this software must not be misrepresented; you must not
		    claim that you wrote the original software. If you use this software
		    in a product, an acknowledgment in the product documentation would be
		    appreciated but is not required.

		    2. Altered source versions must be plainly marked as such, and must not be
		    misrepresented as being the original software.

		    3. This notice may not be removed or altered from any source
		    distribution.
		*/

		/*
		The manual and changelog are in the header file "lodepng.h"
		Rename this file to lodepng.cpp to use it for C++, or to lodepng.c to use it for C.
		*/

/*#if LODEPNG_COMPILE_DISK
#include <limits.h> /* LONG_MAX */
#include <stdio.h> /* file handling */
#endif /* LODEPNG_COMPILE_DISK */

#if LODEPNG_COMPILE_ALLOCATORS
#include <stdlib.h> /* allocations */
#endif /* LODEPNG_COMPILE_ALLOCATORS */*/
		typealias unsigned = uint32;
		typealias size_t = uint32;
		typealias long = int32;
		typealias short = int16;


		const char8* LODEPNG_VERSION_STRING = "20210627";

		/*
		This source file is built up in the following large parts. The code sections
		with the "LODEPNG_COMPILE_" #defines divide this up further in an intermixed way.
		-Tools for C and common code for PNG and Zlib
		-C Code for Zlib (huffman, deflate, ...)
		-C Code for PNG (file format chunks, adam7, PNG filters, color conversions, ...)
		-The C++ wrapper around all of the above
		*/

		/* ////////////////////////////////////////////////////////////////////////// */
		/* ////////////////////////////////////////////////////////////////////////// */
		/* // Tools for C, and common code for PNG and Zlib.                       // */
		/* ////////////////////////////////////////////////////////////////////////// */
		/* ////////////////////////////////////////////////////////////////////////// */

		/*The malloc, realloc and free functions defined here with "lodepng_" in front
		of the name, so that you can easily change them to others related to your
		platform if needed. Everything else in the code calls these. Pass
		-DLODEPNG_NO_COMPILE_ALLOCATORS to the compiler, or comment out
#define LODEPNG_COMPILE_ALLOCATORS in the header, to disable the ones here and
		define them in your own project's source files without needing to change
		lodepng source code. Don't forget to remove "static" if you copypaste them
		from here.*/

#define LODEPNG_COMPILE_PNG
#define LODEPNG_COMPILE_DECODER
#define LODEPNG_COMPILE_DISK
#define LODEPNG_COMPILE_ZLIB

#if LODEPNG_COMPILE_ALLOCATORS
		static void* lodepng_malloc(size_t size) {
#if LODEPNG_MAX_ALLOC
		  if(size > LODEPNG_MAX_ALLOC) return 0;
#endif
		  return malloc(size);
		}

		/* NOTE: when realloc returns NULL, it leaves the original memory untouched */
		static void* lodepng_realloc(void* ptr, size_t new_size) {
#if LODEPNG_MAX_ALLOC
		  if(new_size > LODEPNG_MAX_ALLOC) return 0;
#endif
		  return realloc(ptr, new_size);
		}

		static void lodepng_free(void* ptr) {
		  free(ptr);
		}
#else /*LODEPNG_COMPILE_ALLOCATORS*/
		/* TODO: support giving additional void* payload to the custom allocators */
		static void* lodepng_malloc(size_t size) => Internal.Malloc(size);
		static void* lodepng_realloc(void* ptr, size_t old_size, size_t new_size){
			//crude realloc
			void* newptr = lodepng_malloc(new_size);
			Internal.MemCpy(newptr, ptr, LODEPNG_MIN(old_size, new_size));
			if(ptr != null) lodepng_free(ptr);
			return newptr;
		}
		static void lodepng_free(void* ptr) => Internal.Free(ptr);
#endif /*LODEPNG_COMPILE_ALLOCATORS*/

		/* convince the compiler to inline a function, for use when this measurably improves performance */
		/* inline is not available in C90, but use it when supported by the compiler */
/*#if (defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)) || (defined(__cplusplus) && (__cplusplus >= 199711L))
#define LODEPNG_INLINE inline
#else
#define LODEPNG_INLINE /* not available */
#endif*/

		/* restrict is not available in C90, but use it when supported by the compiler */
/*#if (defined(__GNUC__) && (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1))) ||\
		    (defined(_MSC_VER) && (_MSC_VER >= 1400)) || \
		    (defined(__WATCOMC__) && (__WATCOMC__ >= 1250) && !defined(__cplusplus))
#define LODEPNG_RESTRICT __restrict
#else
#define LODEPNG_RESTRICT /* not available */
#endif*/

		/* Replacements for C library functions such as memcpy and strlen, to support platforms
		where a full C library is not available. The compiler can recognize them and compile
		to something as fast. */

		static void lodepng_memcpy(void* dst,
		                           void* src, size_t size) {
		  size_t i;
		  for(i = 0; i < size; i++) ((char8*)dst)[i] = ((char8*)src)[i];
		}

		static void lodepng_memset(void* dst,
		                           int value, size_t num) {
		  size_t i;
		  for(i = 0; i < num; i++) ((char8*)dst)[i] = (char8)value;
		}

		/* does not check memory out of bounds, do not use on untrusted data */
		static size_t lodepng_strlen(char8* a) {
			var a;
		  char8* orig = a;
		  /* avoid warning about unused function in case of disabled COMPILE... macros */
		  //(void)(&lodepng_strlen);
		  while(*a != 0) a++;
		  return (size_t)(a - orig);
		}

[Inline] static T LODEPNG_MAX<T>(T a, T b) where bool : operator T > T => (((a) > (b)) ? (a) : (b));
[Inline] static T LODEPNG_MIN<T>(T a, T b) where bool  : operator T > T => (((a) < (b)) ? (a) : (b));
[Inline] static T LODEPNG_ABS<T>(T x) where bool : operator T > T where T : operator explicit int where T : operator - T => ((x) < (.)0 ? -(x) : (x));

#if LODEPNG_COMPILE_PNG || LODEPNG_COMPILE_DECODER
		/* Safely check if adding two integers will overflow (no undefined
		behavior, compiler removing the code, etc...) and output result. */
		static bool lodepng_addofl(size_t a, size_t b, size_t* result) {
		  *result = a + b; /* Unsigned addition is well defined and safe in C90 */
		  return *result < a;
		}
#endif /*defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_DECODER)*/

#if LODEPNG_COMPILE_DECODER
		/* Safely check if multiplying two integers will overflow (no undefined
		behavior, compiler removing the code, etc...) and output result. */
		static bool lodepng_mulofl(size_t a, size_t b, size_t* result) {
		  *result = a * b; /* Unsigned multiplication is well defined and safe in C90 */
		  return (a != 0 && *result / a != b);
		}

#if LODEPNG_COMPILE_ZLIB
		/* Safely check if a + b > c, even if overflow could happen. */
		static bool lodepng_gtofl(size_t a, size_t b, size_t c) {
		  size_t d = default;
		  if(lodepng_addofl(a, b, &d)) return true;
		  return d > c;
		}
#endif /*LODEPNG_COMPILE_ZLIB*/
#endif /*LODEPNG_COMPILE_DECODER*/


		/*
		Often in case of an error a value is assigned to a variable and then it breaks
		out of a loop (to go to the cleanup phase of a function). This macro does that.
		It makes the error handling code shorter and more readable.

		Example: if(!uivector_resize(&lz77_encoded, datasize)) CERROR_BREAK!(error, 83);
		*/
static mixin CERROR_BREAK(var errorvar, var code){
		  errorvar = code;
		  break;
		}

		/*version of CERROR_BREAK that assumes the common case where the error variable is named "error"*/
//#define CERROR_BREAK!(error, code) CCERROR_BREAK!(error, error, code)

		/*Set error var to the error code, and return it.*/
static mixin CERROR_RETURN_ERROR(var errorvar, var code){
		  errorvar = code;
		  return code;
		}

		/*Try the code, if it returns error, also return the error.*/
static mixin CERROR_TRY_RETURN(var call){
		  unsigned error = call;
		  if(error != 0) return error;
		}

		/*Set error var to the error code, and return from the void function.*/
static mixin CERROR_RETURN(var errorvar, var code){
		  errorvar = code;
		  return;
		}

		/*
		About uivector, ucvector and string:
		-All of them wrap dynamic arrays or text strings in a similar way.
		-LodePNG was originally written in C++. The vectors replace the std::vectors that were used in the C++ version.
		-The string tools are made to avoid problems with compilers that declare things like strncat as deprecated.
		-They're not used in the interface, only internally in this file as static functions.
		-As with many other structs in this file, the init and cleanup functions serve as ctor and dtor.
		*/

#if LODEPNG_COMPILE_ZLIB
#if LODEPNG_COMPILE_ENCODER
		/*dynamic vector of unsigned ints*/
		typedef struct uivector {
		  unsigned* data;
		  size_t size; /*size in number of unsigned longs*/
		  size_t allocsize; /*allocated size in bytes*/
		} uivector;

		static void uivector_cleanup(void* p) {
		  ((uivector*)p).size = ((uivector*)p).allocsize = 0;
		  lodepng_free(((uivector*)p).data);
		  ((uivector*)p).data = NULL;
		}

		/*returns 1 if success, 0 if failure ==> nothing done*/
		static unsigned uivector_resize(uivector* p, size_t size) {
		  size_t allocsize = size * sizeof(unsigned);
		  if(allocsize > p.allocsize) {
		    size_t newsize = allocsize + (p.allocsize >> 1u);
		    void* data = lodepng_realloc(p.data, newsize);
		    if(data) {
		      p.allocsize = newsize;
		      p.data = (unsigned*)data;
		    }
		    else return 0; /*error: not enough memory*/
		  }
		  p.size = size;
		  return 1; /*success*/
		}

		static void uivector_init(uivector* p) {
		  p.data = NULL;
		  p.size = p.allocsize = 0;
		}

		/*returns 1 if success, 0 if failure ==> nothing done*/
		static unsigned uivector_push_back(uivector* p, unsigned c) {
		  if(!uivector_resize(p, p.size + 1)) return 0;
		  p.data[p.size - 1] = c;
		  return 1;
		}
#endif /*LODEPNG_COMPILE_ENCODER*/
#endif /*LODEPNG_COMPILE_ZLIB*/

		/* /////////////////////////////////////////////////////////////////////////// */

		/*dynamic vector of uint8s*/
		struct ucvector {
		  public uint8* data;
		  public size_t size; /*used size*/
		  public size_t allocsize; /*allocated size*/
		}

		/*returns 1 if success, 0 if failure ==> nothing done*/
		static bool ucvector_resize(ucvector* p, size_t size) {
		  if(size > p.allocsize) {
		    size_t newsize = size + (p.allocsize >> 1u);
		    void* data = lodepng_realloc(p.data, p.allocsize, newsize);
		    if(data != null) {
		      p.allocsize = newsize;
		      p.data = (uint8*)data;
		    }
		    else return false; /*error: not enough memory*/
		  }
		  p.size = size;
		  return true; /*success*/
		}

		static ucvector ucvector_init(uint8* buffer, size_t size) {
		  ucvector v;
		  v.data = buffer;
		  v.allocsize = v.size = size;
		  return v;
		}

		/* ////////////////////////////////////////////////////////////////////////// */

#if LODEPNG_COMPILE_PNG
#if LODEPNG_COMPILE_ANCILLARY_CHUNKS

		/*free string pointer and set it to NULL*/
		static void string_cleanup(char** out) {
		  lodepng_free(*out);
		  *out = NULL;
		}

		/*also appends null termination character*/
		static char* alloc_string_sized(const char* in, size_t insize) {
		  char* out = (char*)lodepng_malloc(insize + 1);
		  if(out) {
		    lodepng_memcpy(out, in, insize);
		    out[insize] = 0;
		  }
		  return out;
		}

		/* dynamically allocates a new string with a copy of the null terminated input text */
		static char* alloc_string(const char* in) {
		  return alloc_string_sized(in, lodepng_strlen(in));
		}
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
#endif /*LODEPNG_COMPILE_PNG*/

		/* ////////////////////////////////////////////////////////////////////////// */

#if LODEPNG_COMPILE_DECODER || LODEPNG_COMPILE_PNG
		static unsigned lodepng_read32bitInt(uint8* buffer) {
		  return (((unsigned)buffer[0] << 24u) | ((unsigned)buffer[1] << 16u) |
		         ((unsigned)buffer[2] << 8u) | (unsigned)buffer[3]);
		}
#endif /*defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_PNG)*/

#if LODEPNG_COMPILE_PNG || LODEPNG_COMPILE_ENCODER
		/*buffer must have at least 4 allocated bytes available*/
		static void lodepng_set32bitInt(uint8* buffer, unsigned value) {
		  buffer[0] = (uint8)((value >> 24) & 0xff);
		  buffer[1] = (uint8)((value >> 16) & 0xff);
		  buffer[2] = (uint8)((value >>  8) & 0xff);
		  buffer[3] = (uint8)((value      ) & 0xff);
		}
#endif /*defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_ENCODER)*/

		/* ////////////////////////////////////////////////////////////////////////// */
		/* / File IO                                                                / */
		/* ////////////////////////////////////////////////////////////////////////// */

#if LODEPNG_COMPILE_DISK

		/* returns negative value on error. This should be pure C compatible, so no fstat. */
		static long lodepng_filesize(char8* filename) {

			FileStream fs = scope FileStream();
			var result = fs.Open(.(filename), .Open, .Read);

			var length = fs.Length;
			fs.Close();

			return (.)length;
		}

		/* load file into buffer that already has the correct allocated size. Returns error code.*/
		static unsigned lodepng_buffer_file(uint8* _out, size_t size, char8* filename) {
			FileStream fs = scope FileStream();
			var result = fs.Open(.(filename), .Open, .Read);

			int amountread = fs.TryRead(.(_out, size));
			fs.Close();
			if(amountread != size) return 78;
			
		  return 0;
		}

		static unsigned lodepng_load_file(uint8** _out, size_t* outsize, char8* filename) {
		  long size = lodepng_filesize(filename);
		  if(size < 0) return 78;
		  *outsize = (size_t)size;

		  *_out = (uint8*)lodepng_malloc((size_t)size);
		  if((*_out) == null && size > 0) return 83; /*the above malloc failed*/

		  return lodepng_buffer_file(*_out, (size_t)size, filename);
		}

		/*write given buffer to the file, overwriting the file, it doesn't append to it.*/
		static unsigned lodepng_save_file(uint8* buffer, size_t buffersize, char8* filename) {
			FileStream fs = scope FileStream();
			var result = fs.Open(.(filename), .Create , .Write);

			fs.TryWrite(.(buffer, buffersize));
			fs.Close();
		  return 0;
		}

#endif /*LODEPNG_COMPILE_DISK*/

		/* ////////////////////////////////////////////////////////////////////////// */
		/* ////////////////////////////////////////////////////////////////////////// */
		/* // End of common code and tools. Begin of Zlib related code.            // */
		/* ////////////////////////////////////////////////////////////////////////// */
		/* ////////////////////////////////////////////////////////////////////////// */

#if LODEPNG_COMPILE_ZLIB
#if LODEPNG_COMPILE_ENCODER

		typedef struct {
		  ucvector* data;
		  uint8 bp; /*ok to overflow, indicates bit pos inside byte*/
		} LodePNGBitWriter;

		static void LodePNGBitWriter_init(LodePNGBitWriter* writer, ucvector* data) {
		  writer.data = data;
		  writer.bp = 0;
		}

		/*TODO: this ignores potential out of memory errors*/
#define WRITEBIT(writer, bit){\
		  /* append new byte */\
		  if(((writer.bp) & 7u) == 0) {\
		    if(!ucvector_resize(writer.data, writer.data.size + 1)) return;\
		    writer.data.data[writer.data.size - 1] = 0;\
		  }\
		  (writer.data.data[writer.data.size - 1]) |= (bit << ((writer.bp) & 7u));\
		  ++writer.bp;\
		}

		/* LSB of value is written first, and LSB of bytes is used first */
		static void writeBits(LodePNGBitWriter* writer, unsigned value, size_t nbits) {
		  if(nbits == 1) { /* compiler should statically compile this case if nbits == 1 */
		    WRITEBIT(writer, value);
		  } else {
		    /* TODO: increase output size only once here rather than in each WRITEBIT */
		    size_t i;
		    for(i = 0; i != nbits; ++i) {
		      WRITEBIT(writer, (uint8)((value >> i) & 1));
		    }
		  }
		}

		/* This one is to use for adding huffman symbol, the value bits are written MSB first */
		static void writeBitsReversed(LodePNGBitWriter* writer, unsigned value, size_t nbits) {
		  size_t i;
		  for(i = 0; i != nbits; ++i) {
		    /* TODO: increase output size only once here rather than in each WRITEBIT */
		    WRITEBIT(writer, (uint8)((value >> (nbits - 1u - i)) & 1u));
		  }
		}
#endif /*LODEPNG_COMPILE_ENCODER*/

#if LODEPNG_COMPILE_DECODER

		struct LodePNGBitReader{
		  public uint8* data;
		  public size_t size; /*size of data in bytes*/
		  public size_t bitsize; /*size of data in bits, end of valid bp values, should be 8*size*/
		  public size_t bp;
		  public unsigned buffer; /*buffer for reading bits. NOTE: 'unsigned' must support at least 32 bits*/
		}

		/* data size argument is in bytes. Returns error if size too large causing overflow */
		static unsigned LodePNGBitReader_init(LodePNGBitReader* reader, uint8* data, size_t size) {
		  size_t temp;
		  reader.data = data;
		  reader.size = size;
		  /* size in bits, return error if overflow (if size_t is 32 bit this supports up to 500MB)  */
		  if(lodepng_mulofl(size, 8u, &reader.bitsize)) return 105;
		  /*ensure incremented bp can be compared to bitsize without overflow even when it would be incremented 32 too much and
		  trying to ensure 32 more bits*/
		  if(lodepng_addofl(reader.bitsize, 64u, &temp)) return 105;
		  reader.bp = 0;
		  reader.buffer = 0;
		  return 0; /*ok*/
		}

		/*
		ensureBits functions:
		Ensures the reader can at least read nbits bits in one or more readBits calls,
		safely even if not enough bits are available.
		Returns 1 if there are enough bits available, 0 if not.
		*/

		/*See ensureBits documentation above. This one ensures exactly 1 bit */
		/*static unsigned ensureBits1(LodePNGBitReader* reader) {
		  if(reader.bp >= reader.bitsize) return 0;
		  reader.buffer = (unsigned)reader.data[reader.bp >> 3u] >> (reader.bp & 7u);
		  return 1;
		}*/

		/*See ensureBits documentation above. This one ensures up to 9 bits */
		static bool ensureBits9(LodePNGBitReader* reader, size_t nbits) {
		  size_t start = reader.bp >> 3u;
		  size_t size = reader.size;
		  if(start + 1u < size) {
		    reader.buffer = (unsigned)reader.data[start + 0] | ((unsigned)reader.data[start + 1] << 8u);
		    reader.buffer >>= (reader.bp & 7u);
		    return true;
		  } else {
		    reader.buffer = 0;
		    if(start + 0u < size) reader.buffer |= reader.data[start + 0];
		    reader.buffer >>= (reader.bp & 7u);
		    return reader.bp + nbits <= reader.bitsize;
		  }
		}

		/*See ensureBits documentation above. This one ensures up to 17 bits */
		static bool ensureBits17(LodePNGBitReader* reader, size_t nbits) {
		  size_t start = reader.bp >> 3u;
		  size_t size = reader.size;
		  if(start + 2u < size) {
		    reader.buffer = (unsigned)reader.data[start + 0] | ((unsigned)reader.data[start + 1] << 8u) |
		                     ((unsigned)reader.data[start + 2] << 16u);
		    reader.buffer >>= (reader.bp & 7u);
		    return true;
		  } else {
		    reader.buffer = 0;
		    if(start + 0u < size) reader.buffer |= reader.data[start + 0];
		    if(start + 1u < size) reader.buffer |= ((unsigned)reader.data[start + 1] << 8u);
		    reader.buffer >>= (reader.bp & 7u);
		    return reader.bp + nbits <= reader.bitsize;
		  }
		}

		/*See ensureBits documentation above. This one ensures up to 25 bits */
		static /*LODEPNG_INLINE*/ bool ensureBits25(LodePNGBitReader* reader, size_t nbits) {
		  size_t start = reader.bp >> 3u;
		  size_t size = reader.size;
		  if(start + 3u < size) {
		    reader.buffer = (unsigned)reader.data[start + 0] | ((unsigned)reader.data[start + 1] << 8u) |
		                     ((unsigned)reader.data[start + 2] << 16u) | ((unsigned)reader.data[start + 3] << 24u);
		    reader.buffer >>= (reader.bp & 7u);
		    return true;
		  } else {
		    reader.buffer = 0;
		    if(start + 0u < size) reader.buffer |= reader.data[start + 0];
		    if(start + 1u < size) reader.buffer |= ((unsigned)reader.data[start + 1] << 8u);
		    if(start + 2u < size) reader.buffer |= ((unsigned)reader.data[start + 2] << 16u);
		    reader.buffer >>= (reader.bp & 7u);
		    return reader.bp + nbits <= reader.bitsize;
		  }
		}

		/*See ensureBits documentation above. This one ensures up to 32 bits */
		static /*LODEPNG_INLINE*/ bool ensureBits32(LodePNGBitReader* reader, size_t nbits) {
		  size_t start = reader.bp >> 3u;
		  size_t size = reader.size;
		  if(start + 4u < size) {
		    reader.buffer = (unsigned)reader.data[start + 0] | ((unsigned)reader.data[start + 1] << 8u) |
		                     ((unsigned)reader.data[start + 2] << 16u) | ((unsigned)reader.data[start + 3] << 24u);
		    reader.buffer >>= (reader.bp & 7u);
		    reader.buffer |= (((unsigned)reader.data[start + 4] << 24u) << (8u - (reader.bp & 7u)));
		    return true;
		  } else {
		    reader.buffer = 0;
		    if(start + 0u < size) reader.buffer |= reader.data[start + 0];
		    if(start + 1u < size) reader.buffer |= ((unsigned)reader.data[start + 1] << 8u);
		    if(start + 2u < size) reader.buffer |= ((unsigned)reader.data[start + 2] << 16u);
		    if(start + 3u < size) reader.buffer |= ((unsigned)reader.data[start + 3] << 24u);
		    reader.buffer >>= (reader.bp & 7u);
		    return reader.bp + nbits <= reader.bitsize;
		  }
		}

		/* Get bits without advancing the bit pointer. Must have enough bits available with ensureBits. Max nbits is 31. */
		static unsigned peekBits(LodePNGBitReader* reader, size_t nbits) {
		  /* The shift allows nbits to be only up to 31. */
		  return reader.buffer & ((1u << nbits) - 1u);
		}

		/* Must have enough bits available with ensureBits */
		static void advanceBits(LodePNGBitReader* reader, size_t nbits) {
		  reader.buffer >>= nbits;
		  reader.bp += nbits;
		}

		/* Must have enough bits available with ensureBits */
		static unsigned readBits(LodePNGBitReader* reader, size_t nbits) {
		  unsigned result = peekBits(reader, nbits);
		  advanceBits(reader, nbits);
		  return result;
		}

		/* Public for testing only. steps and result must have numsteps values. */
		unsigned lode_png_test_bitreader(uint8* data, size_t size,
		                                 size_t numsteps, size_t* steps, unsigned* result) {
		  size_t i;
		  LodePNGBitReader reader;
		  unsigned error = LodePNGBitReader_init(&reader, data, size);
		  if(error != 0) return 0;
		  for(i = 0; i < numsteps; i++) {
		    size_t step = steps[i];
		    bool ok;
		    if(step > 25) ok = ensureBits32(&reader, step);
		    else if(step > 17) ok = ensureBits25(&reader, step);
		    else if(step > 9) ok = ensureBits17(&reader, step);
		    else ok = ensureBits9(&reader, step);
		    if(!ok) return 0;
		    result[i] = readBits(&reader, step);
		  }
		  return 1;
		}
#endif /*LODEPNG_COMPILE_DECODER*/

		static unsigned reverseBits(unsigned bits, unsigned num) {
		  /*TODO: implement faster lookup table based version when needed*/
		  unsigned i, result = 0;
		  for(i = 0; i < num; i++) result |= ((bits >> (num - i - 1u)) & 1u) << i;
		  return result;
		}

		/* ////////////////////////////////////////////////////////////////////////// */
		/* / Deflate - Huffman                                                      / */
		/* ////////////////////////////////////////////////////////////////////////// */

const int FIRST_LENGTH_CODE_INDEX = 257;
const int LAST_LENGTH_CODE_INDEX = 285;
		/*256 literals, the end code, some length codes, and 2 unused codes*/
const int NUM_DEFLATE_CODE_SYMBOLS = 288;
		/*the distance codes have their own symbols, 30 used, 2 unused*/
const int NUM_DISTANCE_SYMBOLS = 32;
		/*the code length codes. 0-15: code lengths, 16: copy previous 3-6 times, 17: 3-10 zeros, 18: 11-138 zeros*/
const int NUM_CODE_LENGTH_CODES = 19;

		/*the base lengths represented by codes 257-285*/
		const unsigned[29] LENGTHBASE
		  = .(3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 35, 43, 51, 59,
		     67, 83, 99, 115, 131, 163, 195, 227, 258);

		/*the extra bits used by codes 257-285 (added to base length)*/
		const unsigned[29] LENGTHEXTRA
		  = .(0, 0, 0, 0, 0, 0, 0,  0,  1,  1,  1,  1,  2,  2,  2,  2,  3,  3,  3,  3,
		      4,  4,  4,   4,   5,   5,   5,   5,   0);

		/*the base backwards distances (the bits of distance codes appear after length codes and use their own huffman tree)*/
		const unsigned[30] DISTANCEBASE
		  = .(1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385, 513,
		     769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577);

		/*the extra bits of backwards distances (added to base)*/
		const unsigned[30] DISTANCEEXTRA
		  = .(0, 0, 0, 0, 1, 1, 2,  2,  3,  3,  4,  4,  5,  5,   6,   6,   7,   7,   8,
		       8,    9,    9,   10,   10,   11,   11,   12,    12,    13,    13);

		/*the order in which "code length alphabet code lengths" are stored as specified by deflate, out of this the huffman
		tree of the dynamic huffman tree lengths is generated*/
		const unsigned[NUM_CODE_LENGTH_CODES] CLCL_ORDER
		  = .(16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15);

		/* ////////////////////////////////////////////////////////////////////////// */

		/*
		Huffman tree struct, containing multiple representations of the tree
		*/
		struct HuffmanTree {
		  public unsigned* codes; /*the huffman codes (bit patterns representing the symbols)*/
		  public unsigned* lengths; /*the lengths of the huffman codes*/
		  public unsigned maxbitlen; /*maximum number of bits a single code can get*/
		  public unsigned numcodes; /*number of symbols in the alphabet = number of codes*/
		  /* for reading only */
		  public uint8* table_len; /*length of symbol from lookup table, or max length if secondary lookup needed*/
		  public uint16* table_value; /*value of symbol from lookup table, or pointer to secondary table if needed*/
		} //HuffmanTree;

		static void HuffmanTree_init(HuffmanTree* tree) {
		  tree.codes = null;
		  tree.lengths = null;
		  tree.table_len = null;
		  tree.table_value = null;
		}

		static void HuffmanTree_cleanup(HuffmanTree* tree) {
		  lodepng_free(tree.codes);
		  lodepng_free(tree.lengths);
		  lodepng_free(tree.table_len);
		  lodepng_free(tree.table_value);
		}

		/* amount of bits for first huffman table lookup (aka root bits), see HuffmanTree_makeTable and huffmanDecodeSymbol.*/
		/* values 8u and 9u work the fastest */
const int FIRSTBITS = 9u;

		/* a symbol value too big to represent any valid symbol, to indicate reading disallowed huffman bits combination,
		which is possible in case of only 0 or 1 present symbols. */
const int INVALIDSYMBOL = 65535u;

		/* make table for huffman decoding */
		static unsigned HuffmanTree_makeTable(HuffmanTree* tree) {
		  const unsigned headsize = 1u << FIRSTBITS; /*size of the first table*/
		  const unsigned mask = (1u << FIRSTBITS) /*headsize*/ - 1u;
		  size_t i, numpresent, pointer, size; /*total table size*/
		  unsigned* maxlens = (unsigned*)lodepng_malloc(headsize * sizeof(unsigned));
		  if(maxlens == null) return 83; /*alloc fail*/

		  /* compute maxlens: max total bit length of symbols sharing prefix in the first table*/
		  lodepng_memset(maxlens, 0, headsize * sizeof(unsigned));
		  for(i = 0; i < tree.numcodes; i++) {
		    unsigned symbol = tree.codes[i];
		    unsigned l = tree.lengths[i];
		    unsigned index;
		    if(l <= FIRSTBITS) continue; /*symbols that fit in first table don't increase secondary table size*/
		    /*get the FIRSTBITS MSBs, the MSBs of the symbol are encoded first. See later comment about the reversing*/
		    index = reverseBits(symbol >> (l - FIRSTBITS), FIRSTBITS);
		    maxlens[index] = LODEPNG_MAX(maxlens[index], l);
		  }
		  /* compute total table size: size of first table plus all secondary tables for symbols longer than FIRSTBITS */
		  size = headsize;
		  for(i = 0; i < headsize; ++i) {
		    unsigned l = maxlens[i];
		    if(l > FIRSTBITS) size += (1u << (l - FIRSTBITS));
		  }
		  tree.table_len = (uint8*)lodepng_malloc(size * sizeof(uint8));
		  tree.table_value = (uint16*)lodepng_malloc(size * sizeof(uint16));
		  if(tree.table_len == null || tree.table_value == null) {
		    lodepng_free(maxlens);
		    /* freeing tree.table values is done at a higher scope */
		    return 83; /*alloc fail*/
		  }
		  /*initialize with an invalid length to indicate unused entries*/
		  for(i = 0; i < size; ++i) tree.table_len[i] = 16;

		  /*fill in the first table for long symbols: max prefix size and pointer to secondary tables*/
		  pointer = headsize;
		  for(i = 0; i < headsize; ++i) {
		    unsigned l = maxlens[i];
		    if(l <= FIRSTBITS) continue;
		    tree.table_len[i] = (.)l;
		    tree.table_value[i] = (.)pointer;
		    pointer += (1u << (l - FIRSTBITS));
		  }
		  lodepng_free(maxlens);

		  /*fill in the first table for short symbols, or secondary table for long symbols*/
		  numpresent = 0;
		  for(i = 0; i < tree.numcodes; ++i) {
		    unsigned l = tree.lengths[i];
		    unsigned symbol = tree.codes[i]; /*the huffman bit pattern. i itself is the value.*/
		    /*reverse bits, because the huffman bits are given in MSB first order but the bit reader reads LSB first*/
		    unsigned reverse = reverseBits(symbol, l);
		    if(l == 0) continue;
		    numpresent++;

		    if(l <= FIRSTBITS) {
		      /*short symbol, fully in first table, replicated num times if l < FIRSTBITS*/
		      unsigned num = 1u << (FIRSTBITS - l);
		      unsigned j;
		      for(j = 0; j < num; ++j) {
		        /*bit reader will read the l bits of symbol first, the remaining FIRSTBITS - l bits go to the MSB's*/
		        unsigned index = reverse | (j << l);
		        if(tree.table_len[index] != 16) return 55; /*invalid tree: long symbol shares prefix with short symbol*/
		        tree.table_len[index] = (.)l;
		        tree.table_value[index] = (.)i;
		      }
		    } else {
		      /*long symbol, shares prefix with other long symbols in first lookup table, needs second lookup*/
		      /*the FIRSTBITS MSBs of the symbol are the first table index*/
		      unsigned index = reverse & mask;
		      unsigned maxlen = tree.table_len[index];
		      /*log2 of secondary table length, should be >= l - FIRSTBITS*/
		      unsigned tablelen = maxlen - FIRSTBITS;
		      unsigned start = tree.table_value[index]; /*starting index in secondary table*/
		      unsigned num = 1u << (tablelen - (l - FIRSTBITS)); /*amount of entries of this symbol in secondary table*/
		      unsigned j;
		      if(maxlen < l) return 55; /*invalid tree: long symbol shares prefix with short symbol*/
		      for(j = 0; j < num; ++j) {
		        unsigned reverse2 = reverse >> FIRSTBITS; /* l - FIRSTBITS bits */
		        unsigned index2 = start + (reverse2 | (j << (l - FIRSTBITS)));
		        tree.table_len[index2] = (.)l;
		        tree.table_value[index2] = (.)i;
		      }
		    }
		  }

		  if(numpresent < 2) {
		    /* In case of exactly 1 symbol, in theory the huffman symbol needs 0 bits,
		    but deflate uses 1 bit instead. In case of 0 symbols, no symbols can
		    appear at all, but such huffman tree could still exist (e.g. if distance
		    codes are never used). In both cases, not all symbols of the table will be
		    filled in. Fill them in with an invalid symbol value so returning them from
		    huffmanDecodeSymbol will cause error. */
		    for(i = 0; i < size; ++i) {
		      if(tree.table_len[i] == 16) {
		        /* As length, use a value smaller than FIRSTBITS for the head table,
		        and a value larger than FIRSTBITS for the secondary table, to ensure
		        valid behavior for advanceBits when reading this symbol. */
		        tree.table_len[i] = (i < headsize) ? 1 : (FIRSTBITS + 1);
		        tree.table_value[i] = INVALIDSYMBOL;
		      }
		    }
		  } else {
		    /* A good huffman tree has N * 2 - 1 nodes, of which N - 1 are internal nodes.
		    If that is not the case (due to too long length codes), the table will not
		    have been fully used, and this is an error (not all bit combinations can be
		    decoded): an oversubscribed huffman tree, indicated by error 55. */
		    for(i = 0; i < size; ++i) {
		      if(tree.table_len[i] == 16) return 55;
		    }
		  }

		  return 0;
		}

		/*
		Second step for the ...makeFromLengths and ...makeFromFrequencies functions.
		numcodes, lengths and maxbitlen must already be filled in correctly. return
		value is error.
		*/
		static unsigned HuffmanTree_makeFromLengths2(HuffmanTree* tree) {
		  unsigned* blcount;
		  unsigned* nextcode;
		  unsigned error = 0;
		  unsigned bits, n;

		  tree.codes = (unsigned*)lodepng_malloc(tree.numcodes * sizeof(unsigned));
		  blcount = (unsigned*)lodepng_malloc((tree.maxbitlen + 1) * sizeof(unsigned));
		  nextcode = (unsigned*)lodepng_malloc((tree.maxbitlen + 1) * sizeof(unsigned));
		  if(tree.codes == null || blcount == null || nextcode == null) error = 83; /*alloc fail*/

		  if(error == 0) {
		    for(n = 0; n != tree.maxbitlen + 1; n++) blcount[n] = nextcode[n] = 0;
		    /*step 1: count number of instances of each code length*/
		    for(bits = 0; bits != tree.numcodes; ++bits) ++blcount[tree.lengths[bits]];
		    /*step 2: generate the nextcode values*/
		    for(bits = 1; bits <= tree.maxbitlen; ++bits) {
		      nextcode[bits] = (nextcode[bits - 1] + blcount[bits - 1]) << 1u;
		    }
		    /*step 3: generate all the codes*/
		    for(n = 0; n != tree.numcodes; ++n) {
		      if(tree.lengths[n] != 0) {
		        tree.codes[n] = nextcode[tree.lengths[n]]++;
		        /*remove superfluous bits from the code*/
		        tree.codes[n] &= ((1u << tree.lengths[n]) - 1u);
		      }
		    }
		  }

		  lodepng_free(blcount);
		  lodepng_free(nextcode);

		  if(error == 0) error = HuffmanTree_makeTable(tree);
		  return error;
		}

		/*
		given the code lengths (as stored in the PNG file), generate the tree as defined
		by Deflate. maxbitlen is the maximum bits that a code in the tree can have.
		return value is error.
		*/
		static unsigned HuffmanTree_makeFromLengths(HuffmanTree* tree, unsigned* bitlen,
		                                            size_t numcodes, unsigned maxbitlen) {
		  unsigned i;
		  tree.lengths = (unsigned*)lodepng_malloc(numcodes * sizeof(unsigned));
		  if(tree.lengths == null) return 83; /*alloc fail*/
		  for(i = 0; i != numcodes; ++i) tree.lengths[i] = bitlen[i];
		  tree.numcodes = (unsigned)numcodes; /*number of symbols*/
		  tree.maxbitlen = maxbitlen;
		  return HuffmanTree_makeFromLengths2(tree);
		}

#if LODEPNG_COMPILE_ENCODER

		/*BPM: Boundary Package Merge, see "A Fast and Space-Economical Algorithm for Length-Limited Coding",
		Jyrki Katajainen, Alistair Moffat, Andrew Turpin, 1995.*/

		/*chain node for boundary package merge*/
		typedef struct BPMNode {
		  int weight; /*the sum of all weights in this chain*/
		  unsigned index; /*index of this leaf node (called "count" in the paper)*/
		  struct BPMNode* tail; /*the next nodes in this chain (null if last)*/
		  int in_use;
		} BPMNode;

		/*lists of chains*/
		typedef struct BPMLists {
		  /*memory pool*/
		  unsigned memsize;
		  BPMNode* memory;
		  unsigned numfree;
		  unsigned nextfree;
		  BPMNode** freelist;
		  /*two heads of lookahead chains per list*/
		  unsigned listsize;
		  BPMNode** chains0;
		  BPMNode** chains1;
		} BPMLists;

		/*creates a new chain node with the given parameters, from the memory in the lists */
		static BPMNode* bpmnode_create(BPMLists* lists, int weight, unsigned index, BPMNode* tail) {
		  unsigned i;
		  BPMNode* result;

		  /*memory full, so garbage collect*/
		  if(lists.nextfree >= lists.numfree) {
		    /*mark only those that are in use*/
		    for(i = 0; i != lists.memsize; ++i) lists.memory[i].in_use = 0;
		    for(i = 0; i != lists.listsize; ++i) {
		      BPMNode* node;
		      for(node = lists.chains0[i]; node != 0; node = node.tail) node.in_use = 1;
		      for(node = lists.chains1[i]; node != 0; node = node.tail) node.in_use = 1;
		    }
		    /*collect those that are free*/
		    lists.numfree = 0;
		    for(i = 0; i != lists.memsize; ++i) {
		      if(!lists.memory[i].in_use) lists.freelist[lists.numfree++] = &lists.memory[i];
		    }
		    lists.nextfree = 0;
		  }

		  result = lists.freelist[lists.nextfree++];
		  result.weight = weight;
		  result.index = index;
		  result.tail = tail;
		  return result;
		}

		/*sort the leaves with stable mergesort*/
		static void bpmnode_sort(BPMNode* leaves, size_t num) {
		  BPMNode* mem = (BPMNode*)lodepng_malloc(sizeof(*leaves) * num);
		  size_t width, counter = 0;
		  for(width = 1; width < num; width *= 2) {
		    BPMNode* a = (counter & 1) ? mem : leaves;
		    BPMNode* b = (counter & 1) ? leaves : mem;
		    size_t p;
		    for(p = 0; p < num; p += 2 * width) {
		      size_t q = (p + width > num) ? num : (p + width);
		      size_t r = (p + 2 * width > num) ? num : (p + 2 * width);
		      size_t i = p, j = q, k;
		      for(k = p; k < r; k++) {
		        if(i < q && (j >= r || a[i].weight <= a[j].weight)) b[k] = a[i++];
		        else b[k] = a[j++];
		      }
		    }
		    counter++;
		  }
		  if(counter & 1) lodepng_memcpy(leaves, mem, sizeof(*leaves) * num);
		  lodepng_free(mem);
		}

		/*Boundary Package Merge step, numpresent is the amount of leaves, and c is the current chain.*/
		static void boundaryPM(BPMLists* lists, BPMNode* leaves, size_t numpresent, int c, int num) {
		  unsigned lastindex = lists.chains1[c].index;

		  if(c == 0) {
		    if(lastindex >= numpresent) return;
		    lists.chains0[c] = lists.chains1[c];
		    lists.chains1[c] = bpmnode_create(lists, leaves[lastindex].weight, lastindex + 1, 0);
		  } else {
		    /*sum of the weights of the head nodes of the previous lookahead chains.*/
		    int sum = lists.chains0[c - 1].weight + lists.chains1[c - 1].weight;
		    lists.chains0[c] = lists.chains1[c];
		    if(lastindex < numpresent && sum > leaves[lastindex].weight) {
		      lists.chains1[c] = bpmnode_create(lists, leaves[lastindex].weight, lastindex + 1, lists.chains1[c].tail);
		      return;
		    }
		    lists.chains1[c] = bpmnode_create(lists, sum, lastindex, lists.chains1[c - 1]);
		    /*in the end we are only interested in the chain of the last list, so no
		    need to recurse if we're at the last one (this gives measurable speedup)*/
		    if(num + 1 < (int)(2 * numpresent - 2)) {
		      boundaryPM(lists, leaves, numpresent, c - 1, num);
		      boundaryPM(lists, leaves, numpresent, c - 1, num);
		    }
		  }
		}

		unsigned lodepng_huffman_code_lengths(unsigned* lengths, const unsigned* frequencies,
		                                      size_t numcodes, unsigned maxbitlen) {
		  unsigned error = 0;
		  unsigned i;
		  size_t numpresent = 0; /*number of symbols with non-zero frequency*/
		  BPMNode* leaves; /*the symbols, only those with > 0 frequency*/

		  if(numcodes == 0) return 80; /*error: a tree of 0 symbols is not supposed to be made*/
		  if((1u << maxbitlen) < (unsigned)numcodes) return 80; /*error: represent all symbols*/

		  leaves = (BPMNode*)lodepng_malloc(numcodes * sizeof(*leaves));
		  if(!leaves) return 83; /*alloc fail*/

		  for(i = 0; i != numcodes; ++i) {
		    if(frequencies[i] > 0) {
		      leaves[numpresent].weight = (int)frequencies[i];
		      leaves[numpresent].index = i;
		      ++numpresent;
		    }
		  }

		  lodepng_memset(lengths, 0, numcodes * sizeof(*lengths));

		  /*ensure at least two present symbols. There should be at least one symbol
		  according to RFC 1951 section 3.2.7. Some decoders incorrectly require two. To
		  make these work as well ensure there are at least two symbols. The
		  Package-Merge code below also doesn't work correctly if there's only one
		  symbol, it'd give it the theoretical 0 bits but in practice zlib wants 1 bit*/
		  if(numpresent == 0) {
		    lengths[0] = lengths[1] = 1; /*note that for RFC 1951 section 3.2.7, only lengths[0] = 1 is needed*/
		  } else if(numpresent == 1) {
		    lengths[leaves[0].index] = 1;
		    lengths[leaves[0].index == 0 ? 1 : 0] = 1;
		  } else {
		    BPMLists lists;
		    BPMNode* node;

		    bpmnode_sort(leaves, numpresent);

		    lists.listsize = maxbitlen;
		    lists.memsize = 2 * maxbitlen * (maxbitlen + 1);
		    lists.nextfree = 0;
		    lists.numfree = lists.memsize;
		    lists.memory = (BPMNode*)lodepng_malloc(lists.memsize * sizeof(*lists.memory));
		    lists.freelist = (BPMNode**)lodepng_malloc(lists.memsize * sizeof(BPMNode*));
		    lists.chains0 = (BPMNode**)lodepng_malloc(lists.listsize * sizeof(BPMNode*));
		    lists.chains1 = (BPMNode**)lodepng_malloc(lists.listsize * sizeof(BPMNode*));
		    if(!lists.memory || !lists.freelist || !lists.chains0 || !lists.chains1) error = 83; /*alloc fail*/

		    if(!error) {
		      for(i = 0; i != lists.memsize; ++i) lists.freelist[i] = &lists.memory[i];

		      bpmnode_create(&lists, leaves[0].weight, 1, 0);
		      bpmnode_create(&lists, leaves[1].weight, 2, 0);

		      for(i = 0; i != lists.listsize; ++i) {
		        lists.chains0[i] = &lists.memory[0];
		        lists.chains1[i] = &lists.memory[1];
		      }

		      /*each boundaryPM call adds one chain to the last list, and we need 2 * numpresent - 2 chains.*/
		      for(i = 2; i != 2 * numpresent - 2; ++i) boundaryPM(&lists, leaves, numpresent, (int)maxbitlen - 1, (int)i);

		      for(node = lists.chains1[maxbitlen - 1]; node; node = node.tail) {
		        for(i = 0; i != node.index; ++i) ++lengths[leaves[i].index];
		      }
		    }

		    lodepng_free(lists.memory);
		    lodepng_free(lists.freelist);
		    lodepng_free(lists.chains0);
		    lodepng_free(lists.chains1);
		  }

		  lodepng_free(leaves);
		  return error;
		}

		/*Create the Huffman tree given the symbol frequencies*/
		static unsigned HuffmanTree_makeFromFrequencies(HuffmanTree* tree, const unsigned* frequencies,
		                                                size_t mincodes, size_t numcodes, unsigned maxbitlen) {
		  unsigned error = 0;
		  while(!frequencies[numcodes - 1] && numcodes > mincodes) --numcodes; /*trim zeroes*/
		  tree.lengths = (unsigned*)lodepng_malloc(numcodes * sizeof(unsigned));
		  if(!tree.lengths) return 83; /*alloc fail*/
		  tree.maxbitlen = maxbitlen;
		  tree.numcodes = (unsigned)numcodes; /*number of symbols*/

		  error = lodepng_huffman_code_lengths(tree.lengths, frequencies, numcodes, maxbitlen);
		  if(!error) error = HuffmanTree_makeFromLengths2(tree);
		  return error;
		}
#endif /*LODEPNG_COMPILE_ENCODER*/

		/*get the literal and length code tree of a deflated block with fixed tree, as per the deflate specification*/
		static unsigned generateFixedLitLenTree(HuffmanTree* tree) {
		  unsigned i, error = 0;
		  unsigned* bitlen = (unsigned*)lodepng_malloc(NUM_DEFLATE_CODE_SYMBOLS * sizeof(unsigned));
		  if(bitlen == null) return 83; /*alloc fail*/

		  /*288 possible codes: 0-255=literals, 256=endcode, 257-285=lengthcodes, 286-287=unused*/
		  for(i =   0; i <= 143; ++i) bitlen[i] = 8;
		  for(i = 144; i <= 255; ++i) bitlen[i] = 9;
		  for(i = 256; i <= 279; ++i) bitlen[i] = 7;
		  for(i = 280; i <= 287; ++i) bitlen[i] = 8;

		  error = HuffmanTree_makeFromLengths(tree, bitlen, NUM_DEFLATE_CODE_SYMBOLS, 15);

		  lodepng_free(bitlen);
		  return error;
		}

		/*get the distance code tree of a deflated block with fixed tree, as specified in the deflate specification*/
		static unsigned generateFixedDistanceTree(HuffmanTree* tree) {
		  unsigned i, error = 0;
		  unsigned* bitlen = (unsigned*)lodepng_malloc(NUM_DISTANCE_SYMBOLS * sizeof(unsigned));
		  if(bitlen == null) return 83; /*alloc fail*/

		  /*there are 32 distance codes, but 30-31 are unused*/
		  for(i = 0; i != NUM_DISTANCE_SYMBOLS; ++i) bitlen[i] = 5;
		  error = HuffmanTree_makeFromLengths(tree, bitlen, NUM_DISTANCE_SYMBOLS, 15);

		  lodepng_free(bitlen);
		  return error;
		}

#if LODEPNG_COMPILE_DECODER

		/*
		returns the code. The bit reader must already have been ensured at least 15 bits
		*/
		static unsigned huffmanDecodeSymbol(LodePNGBitReader* reader, HuffmanTree* codetree) {
		  uint16 code = (.)peekBits(reader, FIRSTBITS);
		  uint16 l = codetree.table_len[code];
		  uint16 value = codetree.table_value[code];
		  if(l <= FIRSTBITS) {
		    advanceBits(reader, l);
		    return value;
		  } else {
		    unsigned index2;
		    advanceBits(reader, FIRSTBITS);
		    index2 = value + peekBits(reader, l - FIRSTBITS);
		    advanceBits(reader, codetree.table_len[index2] - FIRSTBITS);
		    return codetree.table_value[index2];
		  }
		}
#endif /*LODEPNG_COMPILE_DECODER*/

#if LODEPNG_COMPILE_DECODER

		/* ////////////////////////////////////////////////////////////////////////// */
		/* / Inflator (Decompressor)                                                / */
		/* ////////////////////////////////////////////////////////////////////////// */

		/*get the tree of a deflated block with fixed tree, as specified in the deflate specification
		Returns error code.*/
		static unsigned getTreeInflateFixed(HuffmanTree* tree_ll, HuffmanTree* tree_d) {
		  unsigned error = generateFixedLitLenTree(tree_ll);
		  if(error != 0) return error;
		  return generateFixedDistanceTree(tree_d);
		}

		/*get the tree of a deflated block with dynamic tree, the tree itself is also Huffman compressed with a known tree*/
		static unsigned getTreeInflateDynamic(HuffmanTree* tree_ll, HuffmanTree* tree_d,
		                                      LodePNGBitReader* reader) {
		  /*make sure that length values that aren't filled in will be 0, or a wrong tree will be generated*/
		  unsigned error = 0;
		  unsigned n, HLIT, HDIST, HCLEN, i;

		  /*see comments in deflateDynamic for explanation of the context and these variables, it is analogous*/
		  unsigned* bitlen_ll = null; /*lit,len code lengths*/
		  unsigned* bitlen_d = null; /*dist code lengths*/
		  /*code length code lengths ("clcl"), the bit lengths of the huffman tree used to compress bitlen_ll and bitlen_d*/
		  unsigned* bitlen_cl = null;
		  HuffmanTree tree_cl; /*the code tree for code length codes (the huffman tree for compressed huffman trees)*/

		  if(!ensureBits17(reader, 14)) return 49; /*error: the bit pointer is or will go past the memory*/

		  /*number of literal/length codes + 257. Unlike the spec, the value 257 is added to it here already*/
		  HLIT =  readBits(reader, 5) + 257;
		  /*number of distance codes. Unlike the spec, the value 1 is added to it here already*/
		  HDIST = readBits(reader, 5) + 1;
		  /*number of code length codes. Unlike the spec, the value 4 is added to it here already*/
		  HCLEN = readBits(reader, 4) + 4;

		  bitlen_cl = (unsigned*)lodepng_malloc(NUM_CODE_LENGTH_CODES * sizeof(unsigned));
		  if(bitlen_cl == null) return 83 /*alloc fail*/;

		  HuffmanTree_init(&tree_cl);

		  while(error == 0) {
		    /*read the code length codes out of 3 * (amount of code length codes) bits*/
		    if(lodepng_gtofl(reader.bp, HCLEN * 3, reader.bitsize)) {
		      CERROR_BREAK!(error, 50); /*error: the bit pointer is or will go past the memory*/
		    }
		    for(i = 0; i != HCLEN; ++i) {
		      ensureBits9(reader, 3); /*out of bounds already checked above */
		      bitlen_cl[CLCL_ORDER[i]] = readBits(reader, 3);
		    }
		    for(i = HCLEN; i != NUM_CODE_LENGTH_CODES; ++i) {
		      bitlen_cl[CLCL_ORDER[i]] = 0;
		    }

		    error = HuffmanTree_makeFromLengths(&tree_cl, bitlen_cl, NUM_CODE_LENGTH_CODES, 7);
		    if(error != 0) break;

		    /*now we can use this tree to read the lengths for the tree that this function will return*/
		    bitlen_ll = (unsigned*)lodepng_malloc(NUM_DEFLATE_CODE_SYMBOLS * sizeof(unsigned));
		    bitlen_d = (unsigned*)lodepng_malloc(NUM_DISTANCE_SYMBOLS * sizeof(unsigned));
		    if(bitlen_ll == null || bitlen_d == null) CERROR_BREAK!(error, 83 /*alloc fail*/);
		    lodepng_memset(bitlen_ll, 0, NUM_DEFLATE_CODE_SYMBOLS * sizeof(unsigned));
		    lodepng_memset(bitlen_d, 0, NUM_DISTANCE_SYMBOLS * sizeof(unsigned));

		    /*i is the current symbol we're reading in the part that contains the code lengths of lit/len and dist codes*/
		    i = 0;
		    while(i < HLIT + HDIST) {
		      unsigned code;
		      ensureBits25(reader, 22); /* up to 15 bits for huffman code, up to 7 extra bits below*/
		      code = huffmanDecodeSymbol(reader, &tree_cl);
		      if(code <= 15) /*a length code*/ {
		        if(i < HLIT) bitlen_ll[i] = code;
		        else bitlen_d[i - HLIT] = code;
		        ++i;
		      } else if(code == 16) /*repeat previous*/ {
		        unsigned replength = 3; /*read in the 2 bits that indicate repeat length (3-6)*/
		        unsigned value; /*set value to the previous code*/

		        if(i == 0) CERROR_BREAK!(error, 54); /*can't repeat previous if i is 0*/

		        replength += readBits(reader, 2);

		        if(i < HLIT + 1) value = bitlen_ll[i - 1];
		        else value = bitlen_d[i - HLIT - 1];
		        /*repeat this value in the next lengths*/
		        for(n = 0; n < replength; ++n) {
		          if(i >= HLIT + HDIST) CERROR_BREAK!(error, 13); /*error: i is larger than the amount of codes*/
		          if(i < HLIT) bitlen_ll[i] = value;
		          else bitlen_d[i - HLIT] = value;
		          ++i;
		        }
		      } else if(code == 17) /*repeat "0" 3-10 times*/ {
		        unsigned replength = 3; /*read in the bits that indicate repeat length*/
		        replength += readBits(reader, 3);

		        /*repeat this value in the next lengths*/
		        for(n = 0; n < replength; ++n) {
		          if(i >= HLIT + HDIST) CERROR_BREAK!(error, 14); /*error: i is larger than the amount of codes*/

		          if(i < HLIT) bitlen_ll[i] = 0;
		          else bitlen_d[i - HLIT] = 0;
		          ++i;
		        }
		      } else if(code == 18) /*repeat "0" 11-138 times*/ {
		        unsigned replength = 11; /*read in the bits that indicate repeat length*/
		        replength += readBits(reader, 7);

		        /*repeat this value in the next lengths*/
		        for(n = 0; n < replength; ++n) {
		          if(i >= HLIT + HDIST) CERROR_BREAK!(error, 15); /*error: i is larger than the amount of codes*/

		          if(i < HLIT) bitlen_ll[i] = 0;
		          else bitlen_d[i - HLIT] = 0;
		          ++i;
		        }
		      } else /*if(code == INVALIDSYMBOL)*/ {
		        CERROR_BREAK!(error, 16); /*error: tried to read disallowed huffman symbol*/
		      }
		      /*check if any of the ensureBits above went out of bounds*/
		      if(reader.bp > reader.bitsize) {
		        /*return error code 10 or 11 depending on the situation that happened in huffmanDecodeSymbol
		        (10=no endcode, 11=wrong jump outside of tree)*/
		        /* TODO: revise error codes 10,11,50: the above comment is no longer valid */
		        CERROR_BREAK!(error, 50); /*error, bit pointer jumps past memory*/
		      }
		    }
		    if(error != 0) break;

		    if(bitlen_ll[256] == 0) CERROR_BREAK!(error, 64); /*the length of the end code 256 must be larger than 0*/

		    /*now we've finally got HLIT and HDIST, so generate the code trees, and the function is done*/
		    error = HuffmanTree_makeFromLengths(tree_ll, bitlen_ll, NUM_DEFLATE_CODE_SYMBOLS, 15);
		    if(error != 0) break;
		    error = HuffmanTree_makeFromLengths(tree_d, bitlen_d, NUM_DISTANCE_SYMBOLS, 15);

		    break; /*end of error-while*/
		  }

		  lodepng_free(bitlen_cl);
		  lodepng_free(bitlen_ll);
		  lodepng_free(bitlen_d);
		  HuffmanTree_cleanup(&tree_cl);

		  return error;
		}

		/*inflate a block with dynamic of fixed Huffman tree. btype must be 1 or 2.*/
		static unsigned inflateHuffmanBlock(ucvector* _out, LodePNGBitReader* reader,
		                                    unsigned btype, size_t max_output_size) {
		  unsigned error = 0;
		  HuffmanTree tree_ll; /*the huffman tree for literal and length codes*/
		  HuffmanTree tree_d; /*the huffman tree for distance codes*/

		  HuffmanTree_init(&tree_ll);
		  HuffmanTree_init(&tree_d);

		  if(btype == 1) error = getTreeInflateFixed(&tree_ll, &tree_d);
		  else /*if(btype == 2)*/ error = getTreeInflateDynamic(&tree_ll, &tree_d, reader);

		  while(error == 0) /*decode all symbols until end reached, breaks at end code*/ {
		    /*code_ll is literal, length or end code*/
		    unsigned code_ll;
		    ensureBits25(reader, 20); /* up to 15 for the huffman symbol, up to 5 for the length extra bits */
		    code_ll = huffmanDecodeSymbol(reader, &tree_ll);
		    if(code_ll <= 255) /*literal symbol*/ {
		      if(!ucvector_resize(_out, _out.size + 1)) CERROR_BREAK!(error, 83 /*alloc fail*/);
		      _out.data[_out.size - 1] = (uint8)code_ll;
		    } else if(code_ll >= FIRST_LENGTH_CODE_INDEX && code_ll <= LAST_LENGTH_CODE_INDEX) /*length code*/ {
		      unsigned code_d, distance;
		      unsigned numextrabits_l, numextrabits_d; /*extra bits for length and distance*/
		      size_t start, backward, length;

		      /*part 1: get length base*/
		      length = LENGTHBASE[code_ll - FIRST_LENGTH_CODE_INDEX];

		      /*part 2: get extra bits and add the value of that to length*/
		      numextrabits_l = LENGTHEXTRA[code_ll - FIRST_LENGTH_CODE_INDEX];
		      if(numextrabits_l != 0) {
		        /* bits already ensured above */
		        length += readBits(reader, numextrabits_l);
		      }

		      /*part 3: get distance code*/
		      ensureBits32(reader, 28); /* up to 15 for the huffman symbol, up to 13 for the extra bits */
		      code_d = huffmanDecodeSymbol(reader, &tree_d);
		      if(code_d > 29) {
		        if(code_d <= 31) {
		          CERROR_BREAK!(error, 18); /*error: invalid distance code (30-31 are never used)*/
		        } else /* if(code_d == INVALIDSYMBOL) */{
		          CERROR_BREAK!(error, 16); /*error: tried to read disallowed huffman symbol*/
		        }
		      }
		      distance = DISTANCEBASE[code_d];

		      /*part 4: get extra bits from distance*/
		      numextrabits_d = DISTANCEEXTRA[code_d];
		      if(numextrabits_d != 0) {
		        /* bits already ensured above */
		        distance += readBits(reader, numextrabits_d);
		      }

		      /*part 5: fill in all the out[n] values based on the length and dist*/
		      start = _out.size;
		      if(distance > start) CERROR_BREAK!(error, 52); /*too long backward distance*/
		      backward = start - distance;

		      if(!ucvector_resize(_out, _out.size + length)) CERROR_BREAK!(error, 83 /*alloc fail*/);
		      if(distance < length) {
		        size_t forward;
		        lodepng_memcpy(_out.data + start, _out.data + backward, distance);
		        start += distance;
		        for(forward = distance; forward < length; ++forward) {
		          _out.data[start++] = _out.data[backward++];
		        }
		      } else {
		        lodepng_memcpy(_out.data + start, _out.data + backward, length);
		      }
		    } else if(code_ll == 256) {
		      break; /*end code, break the loop*/
		    } else /*if(code_ll == INVALIDSYMBOL)*/ {
		      CERROR_BREAK!(error, 16); /*error: tried to read disallowed huffman symbol*/
		    }
		    /*check if any of the ensureBits above went out of bounds*/
		    if(reader.bp > reader.bitsize) {
		      /*return error code 10 or 11 depending on the situation that happened in huffmanDecodeSymbol
		      (10=no endcode, 11=wrong jump outside of tree)*/
		      /* TODO: revise error codes 10,11,50: the above comment is no longer valid */
		      CERROR_BREAK!(error, 51); /*error, bit pointer jumps past memory*/
		    }
		    if(max_output_size != 0 && _out.size > max_output_size) {
		      CERROR_BREAK!(error, 109); /*error, larger than max size*/
		    }
		  }

		  HuffmanTree_cleanup(&tree_ll);
		  HuffmanTree_cleanup(&tree_d);

		  return error;
		}

		static unsigned inflateNoCompression(ucvector* _out, LodePNGBitReader* reader,
		                                     LodePNGDecompressSettings* settings) {
		  size_t bytepos;
		  size_t size = reader.size;
		  unsigned LEN, NLEN, error = 0;

		  /*go to first boundary of byte*/
		  bytepos = (reader.bp + 7u) >> 3u;

		  /*read LEN (2 bytes) and NLEN (2 bytes)*/
		  if(bytepos + 4 >= size) return 52; /*error, bit pointer will jump past memory*/
		  LEN = (unsigned)reader.data[bytepos] + ((unsigned)reader.data[bytepos + 1] << 8u); bytepos += 2;
		  NLEN = (unsigned)reader.data[bytepos] + ((unsigned)reader.data[bytepos + 1] << 8u); bytepos += 2;

		  /*check if 16-bit NLEN is really the one's complement of LEN*/
		  if(settings.ignore_nlen == 0 && LEN + NLEN != 65535) {
		    return 21; /*error: NLEN is not one's complement of LEN*/
		  }

		  if(!ucvector_resize(_out, _out.size + LEN)) return 83; /*alloc fail*/

		  /*read the literal data: LEN bytes are now stored in the out buffer*/
		  if(bytepos + LEN > size) return 23; /*error: reading outside of in buffer*/

		  lodepng_memcpy(_out.data + _out.size - LEN, reader.data + bytepos, LEN);
		  bytepos += LEN;

		  reader.bp = bytepos << 3u;

		  return error;
		}

		static unsigned lodepng_inflatev(ucvector* _out,
		                                 uint8* _in, size_t insize,
		                                 LodePNGDecompressSettings* settings) {
		  unsigned BFINAL = 0;
		  LodePNGBitReader reader;
		  unsigned error = LodePNGBitReader_init(&reader, _in, insize);

		  if(error != 0) return error;

		  while(BFINAL == 0) {
		    unsigned BTYPE;
		    if(!ensureBits9(&reader, 3)) return 52; /*error, bit pointer will jump past memory*/
		    BFINAL = readBits(&reader, 1);
		    BTYPE = readBits(&reader, 2);

		    if(BTYPE == 3) return 20; /*error: invalid BTYPE*/
		    else if(BTYPE == 0) error = inflateNoCompression(_out, &reader, settings); /*no compression*/
		    else error = inflateHuffmanBlock(_out, &reader, BTYPE, settings.max_output_size); /*compression, BTYPE 01 or 10*/
		    if(error == 0 && settings.max_output_size != 0 && _out.size > settings.max_output_size) error = 109;
		    if(error != 0) break;
		  }

		  return error;
		}

		unsigned lodepng_inflate(uint8** _out, size_t* outsize,
		                         uint8* _in, size_t insize,
		                         LodePNGDecompressSettings* settings) {
		  ucvector v = ucvector_init(*_out, *outsize);
		  unsigned error = lodepng_inflatev(&v, _in, insize, settings);
		  *_out = v.data;
		  *outsize = v.size;
		  return error;
		}

		static unsigned inflatev(ucvector* _out, uint8* _in, size_t insize,
		                        LodePNGDecompressSettings* settings) {
		  if(settings.custom_inflate != 0) {
		    unsigned error = settings.custom_inflate(&_out.data, &_out.size, _in, insize, settings);
		    _out.allocsize = _out.size;
		    if(error != 0) {
		      /*the custom inflate is allowed to have its own error codes, however, we translate it to code 110*/
		      error = 110;
		      /*if there's a max output size, and the custom zlib returned error, then indicate that error instead*/
		      if(settings.max_output_size != 0 && _out.size > settings.max_output_size) error = 109;
		    }
		    return error;
		  } else {
		    return lodepng_inflatev(_out, _in, insize, settings);
		  }
		}

#endif /*LODEPNG_COMPILE_DECODER*/

#if LODEPNG_COMPILE_ENCODER

		/* ////////////////////////////////////////////////////////////////////////// */
		/* / Deflator (Compressor)                                                  / */
		/* ////////////////////////////////////////////////////////////////////////// */

		static const size_t MAX_SUPPORTED_DEFLATE_LENGTH = 258;

		/*search the index in the array, that has the largest value smaller than or equal to the given value,
		given array must be sorted (if no value is smaller, it returns the size of the given array)*/
		static size_t searchCodeIndex(const unsigned* array, size_t array_size, size_t value) {
		  /*binary search (only small gain over linear). TODO: use CPU log2 instruction for getting symbols instead*/
		  size_t left = 1;
		  size_t right = array_size - 1;

		  while(left <= right) {
		    size_t mid = (left + right) >> 1;
		    if(array[mid] >= value) right = mid - 1;
		    else left = mid + 1;
		  }
		  if(left >= array_size || array[left] > value) left--;
		  return left;
		}

		static void addLengthDistance(uivector* values, size_t length, size_t distance) {
		  /*values in encoded vector are those used by deflate:
		  0-255: literal bytes
		  256: end
		  257-285: length/distance pair (length code, followed by extra length bits, distance code, extra distance bits)
		  286-287: invalid*/

		  unsigned length_code = (unsigned)searchCodeIndex(LENGTHBASE, 29, length);
		  unsigned extra_length = (unsigned)(length - LENGTHBASE[length_code]);
		  unsigned dist_code = (unsigned)searchCodeIndex(DISTANCEBASE, 30, distance);
		  unsigned extra_distance = (unsigned)(distance - DISTANCEBASE[dist_code]);

		  size_t pos = values.size;
		  /*TODO: return error when this fails (out of memory)*/
		  unsigned ok = uivector_resize(values, values.size + 4);
		  if(ok) {
		    values.data[pos + 0] = length_code + FIRST_LENGTH_CODE_INDEX;
		    values.data[pos + 1] = extra_length;
		    values.data[pos + 2] = dist_code;
		    values.data[pos + 3] = extra_distance;
		  }
		}

		/*3 bytes of data get encoded into two bytes. The hash cannot use more than 3
		bytes as input because 3 is the minimum match length for deflate*/
		static const unsigned HASH_NUM_VALUES = 65536;
		static const unsigned HASH_BIT_MASK = 65535; /*HASH_NUM_VALUES - 1, but C90 does not like that as initializer*/

		typedef struct Hash {
		  int* head; /*hash value to head circular pos - can be outdated if went around window*/
		  /*circular pos to prev circular pos*/
		  uint16* chain;
		  int* val; /*circular pos to hash value*/

		  /*TODO: do this not only for zeros but for any repeated byte. However for PNG
		  it's always going to be the zeros that dominate, so not important for PNG*/
		  int* headz; /*similar to head, but for chainz*/
		  uint16* chainz; /*those with same amount of zeros*/
		  uint16* zeros; /*length of zeros streak, used as a second hash chain*/
		} Hash;

		static unsigned hash_init(Hash* hash, unsigned windowsize) {
		  unsigned i;
		  hash.head = (int*)lodepng_malloc(sizeof(int) * HASH_NUM_VALUES);
		  hash.val = (int*)lodepng_malloc(sizeof(int) * windowsize);
		  hash.chain = (uint16*)lodepng_malloc(sizeof(uint16) * windowsize);

		  hash.zeros = (uint16*)lodepng_malloc(sizeof(uint16) * windowsize);
		  hash.headz = (int*)lodepng_malloc(sizeof(int) * (MAX_SUPPORTED_DEFLATE_LENGTH + 1));
		  hash.chainz = (uint16*)lodepng_malloc(sizeof(uint16) * windowsize);

		  if(!hash.head || !hash.chain || !hash.val  || !hash.headz|| !hash.chainz || !hash.zeros) {
		    return 83; /*alloc fail*/
		  }

		  /*initialize hash table*/
		  for(i = 0; i != HASH_NUM_VALUES; ++i) hash.head[i] = -1;
		  for(i = 0; i != windowsize; ++i) hash.val[i] = -1;
		  for(i = 0; i != windowsize; ++i) hash.chain[i] = i; /*same value as index indicates uninitialized*/

		  for(i = 0; i <= MAX_SUPPORTED_DEFLATE_LENGTH; ++i) hash.headz[i] = -1;
		  for(i = 0; i != windowsize; ++i) hash.chainz[i] = i; /*same value as index indicates uninitialized*/

		  return 0;
		}

		static void hash_cleanup(Hash* hash) {
		  lodepng_free(hash.head);
		  lodepng_free(hash.val);
		  lodepng_free(hash.chain);

		  lodepng_free(hash.zeros);
		  lodepng_free(hash.headz);
		  lodepng_free(hash.chainz);
		}



		static unsigned getHash(const uint8* data, size_t size, size_t pos) {
		  unsigned result = 0;
		  if(pos + 2 < size) {
		    /*A simple shift and xor hash is used. Since the data of PNGs is dominated
		    by zeroes due to the filters, a better hash does not have a significant
		    effect on speed in traversing the chain, and causes more time spend on
		    calculating the hash.*/
		    result ^= ((unsigned)data[pos + 0] << 0u);
		    result ^= ((unsigned)data[pos + 1] << 4u);
		    result ^= ((unsigned)data[pos + 2] << 8u);
		  } else {
		    size_t amount, i;
		    if(pos >= size) return 0;
		    amount = size - pos;
		    for(i = 0; i != amount; ++i) result ^= ((unsigned)data[pos + i] << (i * 8u));
		  }
		  return result & HASH_BIT_MASK;
		}

		static unsigned countZeros(const uint8* data, size_t size, size_t pos) {
		  const uint8* start = data + pos;
		  const uint8* end = start + MAX_SUPPORTED_DEFLATE_LENGTH;
		  if(end > data + size) end = data + size;
		  data = start;
		  while(data != end && *data == 0) ++data;
		  /*subtracting two addresses returned as 32-bit number (max value is MAX_SUPPORTED_DEFLATE_LENGTH)*/
		  return (unsigned)(data - start);
		}

		/*wpos = pos & (windowsize - 1)*/
		static void updateHashChain(Hash* hash, size_t wpos, unsigned hashval, uint16 numzeros) {
		  hash.val[wpos] = (int)hashval;
		  if(hash.head[hashval] != -1) hash.chain[wpos] = hash.head[hashval];
		  hash.head[hashval] = (int)wpos;

		  hash.zeros[wpos] = numzeros;
		  if(hash.headz[numzeros] != -1) hash.chainz[wpos] = hash.headz[numzeros];
		  hash.headz[numzeros] = (int)wpos;
		}

		/*
		LZ77-encode the data. Return value is error code. The input are raw bytes, the output
		is in the form of unsigned integers with codes representing for example literal bytes, or
		length/distance pairs.
		It uses a hash table technique to let it encode faster. When doing LZ77 encoding, a
		sliding window (of windowsize) is used, and all past bytes in that window can be used as
		the "dictionary". A brute force search through all possible distances would be slow, and
		this hash technique is one out of several ways to speed this up.
		*/
		static unsigned encodeLZ77(uivector* out, Hash* hash,
		                           const uint8* in, size_t inpos, size_t insize, unsigned windowsize,
		                           unsigned minmatch, unsigned nicematch, unsigned lazymatching) {
		  size_t pos;
		  unsigned i, error = 0;
		  /*for large window lengths, assume the user wants no compression loss. Otherwise, max hash chain length speedup.*/
		  unsigned maxchainlength = windowsize >= 8192 ? windowsize : windowsize / 8u;
		  unsigned maxlazymatch = windowsize >= 8192 ? MAX_SUPPORTED_DEFLATE_LENGTH : 64;

		  unsigned usezeros = 1; /*not sure if setting it to false for windowsize < 8192 is better or worse*/
		  unsigned numzeros = 0;

		  unsigned offset; /*the offset represents the distance in LZ77 terminology*/
		  unsigned length;
		  unsigned lazy = 0;
		  unsigned lazylength = 0, lazyoffset = 0;
		  unsigned hashval;
		  unsigned current_offset, current_length;
		  unsigned prev_offset;
		  const uint8 *lastptr, *foreptr, *backptr;
		  unsigned hashpos;

		  if(windowsize == 0 || windowsize > 32768) return 60; /*error: windowsize smaller/larger than allowed*/
		  if((windowsize & (windowsize - 1)) != 0) return 90; /*error: must be power of two*/

		  if(nicematch > MAX_SUPPORTED_DEFLATE_LENGTH) nicematch = MAX_SUPPORTED_DEFLATE_LENGTH;

		  for(pos = inpos; pos < insize; ++pos) {
		    size_t wpos = pos & (windowsize - 1); /*position for in 'circular' hash buffers*/
		    unsigned chainlength = 0;

		    hashval = getHash(in, insize, pos);

		    if(usezeros && hashval == 0) {
		      if(numzeros == 0) numzeros = countZeros(in, insize, pos);
		      else if(pos + numzeros > insize || in[pos + numzeros - 1] != 0) --numzeros;
		    } else {
		      numzeros = 0;
		    }

		    updateHashChain(hash, wpos, hashval, numzeros);

		    /*the length and offset found for the current position*/
		    length = 0;
		    offset = 0;

		    hashpos = hash.chain[wpos];

		    lastptr = &in[insize < pos + MAX_SUPPORTED_DEFLATE_LENGTH ? insize : pos + MAX_SUPPORTED_DEFLATE_LENGTH];

		    /*search for the longest string*/
		    prev_offset = 0;
		    for(;;) {
		      if(chainlength++ >= maxchainlength) break;
		      current_offset = (unsigned)(hashpos <= wpos ? wpos - hashpos : wpos - hashpos + windowsize);

		      if(current_offset < prev_offset) break; /*stop when went completely around the circular buffer*/
		      prev_offset = current_offset;
		      if(current_offset > 0) {
		        /*test the next characters*/
		        foreptr = &in[pos];
		        backptr = &in[pos - current_offset];

		        /*common case in PNGs is lots of zeros. Quickly skip over them as a speedup*/
		        if(numzeros >= 3) {
		          unsigned skip = hash.zeros[hashpos];
		          if(skip > numzeros) skip = numzeros;
		          backptr += skip;
		          foreptr += skip;
		        }

		        while(foreptr != lastptr && *backptr == *foreptr) /*maximum supported length by deflate is max length*/ {
		          ++backptr;
		          ++foreptr;
		        }
		        current_length = (unsigned)(foreptr - &in[pos]);

		        if(current_length > length) {
		          length = current_length; /*the longest length*/
		          offset = current_offset; /*the offset that is related to this longest length*/
		          /*jump out once a length of max length is found (speed gain). This also jumps
		          out if length is MAX_SUPPORTED_DEFLATE_LENGTH*/
		          if(current_length >= nicematch) break;
		        }
		      }

		      if(hashpos == hash.chain[hashpos]) break;

		      if(numzeros >= 3 && length > numzeros) {
		        hashpos = hash.chainz[hashpos];
		        if(hash.zeros[hashpos] != numzeros) break;
		      } else {
		        hashpos = hash.chain[hashpos];
		        /*outdated hash value, happens if particular value was not encountered in whole last window*/
		        if(hash.val[hashpos] != (int)hashval) break;
		      }
		    }

		    if(lazymatching) {
		      if(!lazy && length >= 3 && length <= maxlazymatch && length < MAX_SUPPORTED_DEFLATE_LENGTH) {
		        lazy = 1;
		        lazylength = length;
		        lazyoffset = offset;
		        continue; /*try the next byte*/
		      }
		      if(lazy) {
		        lazy = 0;
		        if(pos == 0) CERROR_BREAK!(error, 81);
		        if(length > lazylength + 1) {
		          /*push the previous character as literal*/
		          if(!uivector_push_back(out, in[pos - 1])) CERROR_BREAK!(error, 83 /*alloc fail*/);
		        } else {
		          length = lazylength;
		          offset = lazyoffset;
		          hash.head[hashval] = -1; /*the same hashchain update will be done, this ensures no wrong alteration*/
		          hash.headz[numzeros] = -1; /*idem*/
		          --pos;
		        }
		      }
		    }
		    if(length >= 3 && offset > windowsize) CERROR_BREAK!(error, 86 /*too big (or overflown negative) offset*/);

		    /*encode it as length/distance pair or literal value*/
		    if(length < 3) /*only lengths of 3 or higher are supported as length/distance pair*/ {
		      if(!uivector_push_back(out, in[pos])) CERROR_BREAK!(error, 83 /*alloc fail*/);
		    } else if(length < minmatch || (length == 3 && offset > 4096)) {
		      /*compensate for the fact that longer offsets have more extra bits, a
		      length of only 3 may be not worth it then*/
		      if(!uivector_push_back(out, in[pos])) CERROR_BREAK!(error, 83 /*alloc fail*/);
		    } else {
		      addLengthDistance(out, length, offset);
		      for(i = 1; i < length; ++i) {
		        ++pos;
		        wpos = pos & (windowsize - 1);
		        hashval = getHash(in, insize, pos);
		        if(usezeros && hashval == 0) {
		          if(numzeros == 0) numzeros = countZeros(in, insize, pos);
		          else if(pos + numzeros > insize || in[pos + numzeros - 1] != 0) --numzeros;
		        } else {
		          numzeros = 0;
		        }
		        updateHashChain(hash, wpos, hashval, numzeros);
		      }
		    }
		  } /*end of the loop through each character of input*/

		  return error;
		}

		/* /////////////////////////////////////////////////////////////////////////// */

		static unsigned deflateNoCompression(ucvector* out, const uint8* data, size_t datasize) {
		  /*non compressed deflate block data: 1 bit BFINAL,2 bits BTYPE,(5 bits): it jumps to start of next byte,
		  2 bytes LEN, 2 bytes NLEN, LEN bytes literal DATA*/

		  size_t i, numdeflateblocks = (datasize + 65534u) / 65535u;
		  unsigned datapos = 0;
		  for(i = 0; i != numdeflateblocks; ++i) {
		    unsigned BFINAL, BTYPE, LEN, NLEN;
		    uint8 firstbyte;
		    size_t pos = out.size;

		    BFINAL = (i == numdeflateblocks - 1);
		    BTYPE = 0;

		    LEN = 65535;
		    if(datasize - datapos < 65535u) LEN = (unsigned)datasize - datapos;
		    NLEN = 65535 - LEN;

		    if(!ucvector_resize(out, out.size + LEN + 5)) return 83; /*alloc fail*/

		    firstbyte = (uint8)(BFINAL + ((BTYPE & 1u) << 1u) + ((BTYPE & 2u) << 1u));
		    out.data[pos + 0] = firstbyte;
		    out.data[pos + 1] = (uint8)(LEN & 255);
		    out.data[pos + 2] = (uint8)(LEN >> 8u);
		    out.data[pos + 3] = (uint8)(NLEN & 255);
		    out.data[pos + 4] = (uint8)(NLEN >> 8u);
		    lodepng_memcpy(out.data + pos + 5, data + datapos, LEN);
		    datapos += LEN;
		  }

		  return 0;
		}

		/*
		write the lz77-encoded data, which has lit, len and dist codes, to compressed stream using huffman trees.
		tree_ll: the tree for lit and len codes.
		tree_d: the tree for distance codes.
		*/
		static void writeLZ77data(LodePNGBitWriter* writer, const uivector* lz77_encoded,
		                          const HuffmanTree* tree_ll, const HuffmanTree* tree_d) {
		  size_t i = 0;
		  for(i = 0; i != lz77_encoded.size; ++i) {
		    unsigned val = lz77_encoded.data[i];
		    writeBitsReversed(writer, tree_ll.codes[val], tree_ll.lengths[val]);
		    if(val > 256) /*for a length code, 3 more things have to be added*/ {
		      unsigned length_index = val - FIRST_LENGTH_CODE_INDEX;
		      unsigned n_length_extra_bits = LENGTHEXTRA[length_index];
		      unsigned length_extra_bits = lz77_encoded.data[++i];

		      unsigned distance_code = lz77_encoded.data[++i];

		      unsigned distance_index = distance_code;
		      unsigned n_distance_extra_bits = DISTANCEEXTRA[distance_index];
		      unsigned distance_extra_bits = lz77_encoded.data[++i];

		      writeBits(writer, length_extra_bits, n_length_extra_bits);
		      writeBitsReversed(writer, tree_d.codes[distance_code], tree_d.lengths[distance_code]);
		      writeBits(writer, distance_extra_bits, n_distance_extra_bits);
		    }
		  }
		}

		/*Deflate for a block of type "dynamic", that is, with freely, optimally, created huffman trees*/
		static unsigned deflateDynamic(LodePNGBitWriter* writer, Hash* hash,
		                               const uint8* data, size_t datapos, size_t dataend,
		                               const LodePNGCompressSettings* settings, unsigned final) {
		  unsigned error = 0;

		  /*
		  A block is compressed as follows: The PNG data is lz77 encoded, resulting in
		  literal bytes and length/distance pairs. This is then huffman compressed with
		  two huffman trees. One huffman tree is used for the lit and len values ("ll"),
		  another huffman tree is used for the dist values ("d"). These two trees are
		  stored using their code lengths, and to compress even more these code lengths
		  are also run-length encoded and huffman compressed. This gives a huffman tree
		  of code lengths "cl". The code lengths used to describe this third tree are
		  the code length code lengths ("clcl").
		  */

		  /*The lz77 encoded data, represented with integers since there will also be length and distance codes in it*/
		  uivector lz77_encoded;
		  HuffmanTree tree_ll; /*tree for lit,len values*/
		  HuffmanTree tree_d; /*tree for distance codes*/
		  HuffmanTree tree_cl; /*tree for encoding the code lengths representing tree_ll and tree_d*/
		  unsigned* frequencies_ll = 0; /*frequency of lit,len codes*/
		  unsigned* frequencies_d = 0; /*frequency of dist codes*/
		  unsigned* frequencies_cl = 0; /*frequency of code length codes*/
		  unsigned* bitlen_lld = 0; /*lit,len,dist code lengths (int bits), literally (without repeat codes).*/
		  unsigned* bitlen_lld_e = 0; /*bitlen_lld encoded with repeat codes (this is a rudimentary run length compression)*/
		  size_t datasize = dataend - datapos;

		  /*
		  If we could call "bitlen_cl" the the code length code lengths ("clcl"), that is the bit lengths of codes to represent
		  tree_cl in CLCL_ORDER, then due to the huffman compression of huffman tree representations ("two levels"), there are
		  some analogies:
		  bitlen_lld is to tree_cl what data is to tree_ll and tree_d.
		  bitlen_lld_e is to bitlen_lld what lz77_encoded is to data.
		  bitlen_cl is to bitlen_lld_e what bitlen_lld is to lz77_encoded.
		  */

		  unsigned BFINAL = final;
		  size_t i;
		  size_t numcodes_ll, numcodes_d, numcodes_lld, numcodes_lld_e, numcodes_cl;
		  unsigned HLIT, HDIST, HCLEN;

		  uivector_init(&lz77_encoded);
		  HuffmanTree_init(&tree_ll);
		  HuffmanTree_init(&tree_d);
		  HuffmanTree_init(&tree_cl);
		  /* could fit on stack, but >1KB is on the larger side so allocate instead */
		  frequencies_ll = (unsigned*)lodepng_malloc(286 * sizeof(*frequencies_ll));
		  frequencies_d = (unsigned*)lodepng_malloc(30 * sizeof(*frequencies_d));
		  frequencies_cl = (unsigned*)lodepng_malloc(NUM_CODE_LENGTH_CODES * sizeof(*frequencies_cl));

		  if(!frequencies_ll || !frequencies_d || !frequencies_cl) error = 83; /*alloc fail*/

		  /*This while loop never loops due to a break at the end, it is here to
		  allow breaking out of it to the cleanup phase on error conditions.*/
		  while(!error) {
		    lodepng_memset(frequencies_ll, 0, 286 * sizeof(*frequencies_ll));
		    lodepng_memset(frequencies_d, 0, 30 * sizeof(*frequencies_d));
		    lodepng_memset(frequencies_cl, 0, NUM_CODE_LENGTH_CODES * sizeof(*frequencies_cl));

		    if(settings.use_lz77) {
		      error = encodeLZ77(&lz77_encoded, hash, data, datapos, dataend, settings.windowsize,
		                         settings.minmatch, settings.nicematch, settings.lazymatching);
		      if(error) break;
		    } else {
		      if(!uivector_resize(&lz77_encoded, datasize)) CERROR_BREAK!(error, 83 /*alloc fail*/);
		      for(i = datapos; i < dataend; ++i) lz77_encoded.data[i - datapos] = data[i]; /*no LZ77, but still will be Huffman compressed*/
		    }

		    /*Count the frequencies of lit, len and dist codes*/
		    for(i = 0; i != lz77_encoded.size; ++i) {
		      unsigned symbol = lz77_encoded.data[i];
		      ++frequencies_ll[symbol];
		      if(symbol > 256) {
		        unsigned dist = lz77_encoded.data[i + 2];
		        ++frequencies_d[dist];
		        i += 3;
		      }
		    }
		    frequencies_ll[256] = 1; /*there will be exactly 1 end code, at the end of the block*/

		    /*Make both huffman trees, one for the lit and len codes, one for the dist codes*/
		    error = HuffmanTree_makeFromFrequencies(&tree_ll, frequencies_ll, 257, 286, 15);
		    if(error) break;
		    /*2, not 1, is chosen for mincodes: some buggy PNG decoders require at least 2 symbols in the dist tree*/
		    error = HuffmanTree_makeFromFrequencies(&tree_d, frequencies_d, 2, 30, 15);
		    if(error) break;

		    numcodes_ll = LODEPNG_MIN(tree_ll.numcodes, 286);
		    numcodes_d = LODEPNG_MIN(tree_d.numcodes, 30);
		    /*store the code lengths of both generated trees in bitlen_lld*/
		    numcodes_lld = numcodes_ll + numcodes_d;
		    bitlen_lld = (unsigned*)lodepng_malloc(numcodes_lld * sizeof(*bitlen_lld));
		    /*numcodes_lld_e never needs more size than bitlen_lld*/
		    bitlen_lld_e = (unsigned*)lodepng_malloc(numcodes_lld * sizeof(*bitlen_lld_e));
		    if(!bitlen_lld || !bitlen_lld_e) CERROR_BREAK!(error, 83); /*alloc fail*/
		    numcodes_lld_e = 0;

		    for(i = 0; i != numcodes_ll; ++i) bitlen_lld[i] = tree_ll.lengths[i];
		    for(i = 0; i != numcodes_d; ++i) bitlen_lld[numcodes_ll + i] = tree_d.lengths[i];

		    /*run-length compress bitlen_ldd into bitlen_lld_e by using repeat codes 16 (copy length 3-6 times),
		    17 (3-10 zeroes), 18 (11-138 zeroes)*/
		    for(i = 0; i != numcodes_lld; ++i) {
		      unsigned j = 0; /*amount of repetitions*/
		      while(i + j + 1 < numcodes_lld && bitlen_lld[i + j + 1] == bitlen_lld[i]) ++j;

		      if(bitlen_lld[i] == 0 && j >= 2) /*repeat code for zeroes*/ {
		        ++j; /*include the first zero*/
		        if(j <= 10) /*repeat code 17 supports max 10 zeroes*/ {
		          bitlen_lld_e[numcodes_lld_e++] = 17;
		          bitlen_lld_e[numcodes_lld_e++] = j - 3;
		        } else /*repeat code 18 supports max 138 zeroes*/ {
		          if(j > 138) j = 138;
		          bitlen_lld_e[numcodes_lld_e++] = 18;
		          bitlen_lld_e[numcodes_lld_e++] = j - 11;
		        }
		        i += (j - 1);
		      } else if(j >= 3) /*repeat code for value other than zero*/ {
		        size_t k;
		        unsigned num = j / 6u, rest = j % 6u;
		        bitlen_lld_e[numcodes_lld_e++] = bitlen_lld[i];
		        for(k = 0; k < num; ++k) {
		          bitlen_lld_e[numcodes_lld_e++] = 16;
		          bitlen_lld_e[numcodes_lld_e++] = 6 - 3;
		        }
		        if(rest >= 3) {
		          bitlen_lld_e[numcodes_lld_e++] = 16;
		          bitlen_lld_e[numcodes_lld_e++] = rest - 3;
		        }
		        else j -= rest;
		        i += j;
		      } else /*too short to benefit from repeat code*/ {
		        bitlen_lld_e[numcodes_lld_e++] = bitlen_lld[i];
		      }
		    }

		    /*generate tree_cl, the huffmantree of huffmantrees*/
		    for(i = 0; i != numcodes_lld_e; ++i) {
		      ++frequencies_cl[bitlen_lld_e[i]];
		      /*after a repeat code come the bits that specify the number of repetitions,
		      those don't need to be in the frequencies_cl calculation*/
		      if(bitlen_lld_e[i] >= 16) ++i;
		    }

		    error = HuffmanTree_makeFromFrequencies(&tree_cl, frequencies_cl,
		                                            NUM_CODE_LENGTH_CODES, NUM_CODE_LENGTH_CODES, 7);
		    if(error) break;

		    /*compute amount of code-length-code-lengths to output*/
		    numcodes_cl = NUM_CODE_LENGTH_CODES;
		    /*trim zeros at the end (using CLCL_ORDER), but minimum size must be 4 (see HCLEN below)*/
		    while(numcodes_cl > 4u && tree_cl.lengths[CLCL_ORDER[numcodes_cl - 1u]] == 0) {
		      numcodes_cl--;
		    }

		    /*
		    Write everything into the output

		    After the BFINAL and BTYPE, the dynamic block consists out of the following:
		    - 5 bits HLIT, 5 bits HDIST, 4 bits HCLEN
		    - (HCLEN+4)*3 bits code lengths of code length alphabet
		    - HLIT + 257 code lengths of lit/length alphabet (encoded using the code length
		      alphabet, + possible repetition codes 16, 17, 18)
		    - HDIST + 1 code lengths of distance alphabet (encoded using the code length
		      alphabet, + possible repetition codes 16, 17, 18)
		    - compressed data
		    - 256 (end code)
		    */

		    /*Write block type*/
		    writeBits(writer, BFINAL, 1);
		    writeBits(writer, 0, 1); /*first bit of BTYPE "dynamic"*/
		    writeBits(writer, 1, 1); /*second bit of BTYPE "dynamic"*/

		    /*write the HLIT, HDIST and HCLEN values*/
		    /*all three sizes take trimmed ending zeroes into account, done either by HuffmanTree_makeFromFrequencies
		    or in the loop for numcodes_cl above, which saves space. */
		    HLIT = (unsigned)(numcodes_ll - 257);
		    HDIST = (unsigned)(numcodes_d - 1);
		    HCLEN = (unsigned)(numcodes_cl - 4);
		    writeBits(writer, HLIT, 5);
		    writeBits(writer, HDIST, 5);
		    writeBits(writer, HCLEN, 4);

		    /*write the code lengths of the code length alphabet ("bitlen_cl")*/
		    for(i = 0; i != numcodes_cl; ++i) writeBits(writer, tree_cl.lengths[CLCL_ORDER[i]], 3);

		    /*write the lengths of the lit/len AND the dist alphabet*/
		    for(i = 0; i != numcodes_lld_e; ++i) {
		      writeBitsReversed(writer, tree_cl.codes[bitlen_lld_e[i]], tree_cl.lengths[bitlen_lld_e[i]]);
		      /*extra bits of repeat codes*/
		      if(bitlen_lld_e[i] == 16) writeBits(writer, bitlen_lld_e[++i], 2);
		      else if(bitlen_lld_e[i] == 17) writeBits(writer, bitlen_lld_e[++i], 3);
		      else if(bitlen_lld_e[i] == 18) writeBits(writer, bitlen_lld_e[++i], 7);
		    }

		    /*write the compressed data symbols*/
		    writeLZ77data(writer, &lz77_encoded, &tree_ll, &tree_d);
		    /*error: the length of the end code 256 must be larger than 0*/
		    if(tree_ll.lengths[256] == 0) CERROR_BREAK!(error, 64);

		    /*write the end code*/
		    writeBitsReversed(writer, tree_ll.codes[256], tree_ll.lengths[256]);

		    break; /*end of error-while*/
		  }

		  /*cleanup*/
		  uivector_cleanup(&lz77_encoded);
		  HuffmanTree_cleanup(&tree_ll);
		  HuffmanTree_cleanup(&tree_d);
		  HuffmanTree_cleanup(&tree_cl);
		  lodepng_free(frequencies_ll);
		  lodepng_free(frequencies_d);
		  lodepng_free(frequencies_cl);
		  lodepng_free(bitlen_lld);
		  lodepng_free(bitlen_lld_e);

		  return error;
		}

		static unsigned deflateFixed(LodePNGBitWriter* writer, Hash* hash,
		                             const uint8* data,
		                             size_t datapos, size_t dataend,
		                             const LodePNGCompressSettings* settings, unsigned final) {
		  HuffmanTree tree_ll; /*tree for literal values and length codes*/
		  HuffmanTree tree_d; /*tree for distance codes*/

		  unsigned BFINAL = final;
		  unsigned error = 0;
		  size_t i;

		  HuffmanTree_init(&tree_ll);
		  HuffmanTree_init(&tree_d);

		  error = generateFixedLitLenTree(&tree_ll);
		  if(!error) error = generateFixedDistanceTree(&tree_d);

		  if(!error) {
		    writeBits(writer, BFINAL, 1);
		    writeBits(writer, 1, 1); /*first bit of BTYPE*/
		    writeBits(writer, 0, 1); /*second bit of BTYPE*/

		    if(settings.use_lz77) /*LZ77 encoded*/ {
		      uivector lz77_encoded;
		      uivector_init(&lz77_encoded);
		      error = encodeLZ77(&lz77_encoded, hash, data, datapos, dataend, settings.windowsize,
		                         settings.minmatch, settings.nicematch, settings.lazymatching);
		      if(!error) writeLZ77data(writer, &lz77_encoded, &tree_ll, &tree_d);
		      uivector_cleanup(&lz77_encoded);
		    } else /*no LZ77, but still will be Huffman compressed*/ {
		      for(i = datapos; i < dataend; ++i) {
		        writeBitsReversed(writer, tree_ll.codes[data[i]], tree_ll.lengths[data[i]]);
		      }
		    }
		    /*add END code*/
		    if(!error) writeBitsReversed(writer,tree_ll.codes[256], tree_ll.lengths[256]);
		  }

		  /*cleanup*/
		  HuffmanTree_cleanup(&tree_ll);
		  HuffmanTree_cleanup(&tree_d);

		  return error;
		}

		static unsigned lodepng_deflatev(ucvector* out, const uint8* in, size_t insize,
		                                 const LodePNGCompressSettings* settings) {
		  unsigned error = 0;
		  size_t i, blocksize, numdeflateblocks;
		  Hash hash;
		  LodePNGBitWriter writer;

		  LodePNGBitWriter_init(&writer, out);

		  if(settings.btype > 2) return 61;
		  else if(settings.btype == 0) return deflateNoCompression(out, in, insize);
		  else if(settings.btype == 1) blocksize = insize;
		  else /*if(settings.btype == 2)*/ {
		    /*on PNGs, deflate blocks of 65-262k seem to give most dense encoding*/
		    blocksize = insize / 8u + 8;
		    if(blocksize < 65536) blocksize = 65536;
		    if(blocksize > 262144) blocksize = 262144;
		  }

		  numdeflateblocks = (insize + blocksize - 1) / blocksize;
		  if(numdeflateblocks == 0) numdeflateblocks = 1;

		  error = hash_init(&hash, settings.windowsize);

		  if(!error) {
		    for(i = 0; i != numdeflateblocks && !error; ++i) {
		      unsigned final = (i == numdeflateblocks - 1);
		      size_t start = i * blocksize;
		      size_t end = start + blocksize;
		      if(end > insize) end = insize;

		      if(settings.btype == 1) error = deflateFixed(&writer, &hash, in, start, end, settings, final);
		      else if(settings.btype == 2) error = deflateDynamic(&writer, &hash, in, start, end, settings, final);
		    }
		  }

		  hash_cleanup(&hash);

		  return error;
		}

		unsigned lodepng_deflate(uint8** out, size_t* outsize,
		                         const uint8* in, size_t insize,
		                         const LodePNGCompressSettings* settings) {
		  ucvector v = ucvector_init(*out, *outsize);
		  unsigned error = lodepng_deflatev(&v, in, insize, settings);
		  *out = v.data;
		  *outsize = v.size;
		  return error;
		}

		static unsigned deflate(uint8** out, size_t* outsize,
		                        const uint8* in, size_t insize,
		                        const LodePNGCompressSettings* settings) {
		  if(settings.custom_deflate) {
		    unsigned error = settings.custom_deflate(out, outsize, in, insize, settings);
		    /*the custom deflate is allowed to have its own error codes, however, we translate it to code 111*/
		    return error ? 111 : 0;
		  } else {
		    return lodepng_deflate(out, outsize, in, insize, settings);
		  }
		}

#endif /*LODEPNG_COMPILE_DECODER*/

		/* ////////////////////////////////////////////////////////////////////////// */
		/* / Adler32                                                                / */
		/* ////////////////////////////////////////////////////////////////////////// */

		static unsigned update_adler32(unsigned adler, uint8* data, unsigned len) {
		  unsigned s1 = adler & 0xffffu;
		  unsigned s2 = (adler >> 16u) & 0xffffu;
			var len;
			var data;

		  while(len != 0u) {
		    unsigned i;
		    /*at least 5552 sums can be done before the sums overflow, saving a lot of module divisions*/
		    unsigned amount = len > 5552u ? 5552u : len;
		    len -= amount;
		    for(i = 0; i != amount; ++i) {
		      s1 += (*data++);
		      s2 += s1;
		    }
		    s1 %= 65521u;
		    s2 %= 65521u;
		  }

		  return (s2 << 16u) | s1;
		}

		/*Return the adler32 of the bytes data[0..len-1]*/
		static unsigned adler32(uint8* data, unsigned len) {
		  return update_adler32(1u, data, len);
		}

		/* ////////////////////////////////////////////////////////////////////////// */
		/* / Zlib                                                                   / */
		/* ////////////////////////////////////////////////////////////////////////// */

#if LODEPNG_COMPILE_DECODER

		static unsigned lodepng_zlib_decompressv(ucvector* _out,
		                                         uint8* _in, size_t insize,
		                                         LodePNGDecompressSettings* settings) {
		  unsigned error = 0;
		  unsigned CM, CINFO, FDICT;

		  if(insize < 2) return 53; /*error, size of zlib data too small*/
		  /*read information from zlib header*/
		  if((_in[0] * 256 + _in[1]) % 31 != 0) {
		    /*error: 256 * in[0] + in[1] must be a multiple of 31, the FCHECK value is supposed to be made that way*/
		    return 24;
		  }

		  CM = _in[0] & 15;
		  CINFO = (_in[0] >> 4) & 15;
		  /*FCHECK = in[1] & 31;*/ /*FCHECK is already tested above*/
		  FDICT = (_in[1] >> 5) & 1;
		  /*FLEVEL = (in[1] >> 6) & 3;*/ /*FLEVEL is not used here*/

		  if(CM != 8 || CINFO > 7) {
		    /*error: only compression method 8: inflate with sliding window of 32k is supported by the PNG spec*/
		    return 25;
		  }
		  if(FDICT != 0) {
		    /*error: the specification of PNG says about the zlib stream:
		      "The additional flags shall not specify a preset dictionary."*/
		    return 26;
		  }

		  error = inflatev(_out, _in + 2, insize - 2, settings);
		  if(error != 0) return error;

		  if(settings.ignore_adler32 == 0) {
		    unsigned ADLER32 = lodepng_read32bitInt(&_in[insize - 4]);
		    unsigned checksum = adler32(_out.data, (unsigned)(_out.size));
		    if(checksum != ADLER32) return 58; /*error, adler checksum not correct, data must be corrupted*/
		  }

		  return 0; /*no error*/
		}


		unsigned lodepng_zlib_decompress(uint8** _out, size_t* outsize, uint8* _in,
		                                 size_t insize, LodePNGDecompressSettings* settings) {
		  ucvector v = ucvector_init(*_out, *outsize);
		  unsigned error = lodepng_zlib_decompressv(&v, _in, insize, settings);
		  *_out = v.data;
		  *outsize = v.size;
		  return error;
		}

		/*expected_size is expected output size, to avoid intermediate allocations. Set to 0 if not known. */
		static unsigned zlib_decompress(uint8** _out, size_t* outsize, size_t expected_size,
		                                uint8* _in, size_t insize, LodePNGDecompressSettings* settings) {
		  unsigned error;
		  if(settings.custom_zlib != 0) {
		    error = settings.custom_zlib(_out, outsize, _in, insize, settings);
		    if(error != 0) {
		      /*the custom zlib is allowed to have its own error codes, however, we translate it to code 110*/
		      error = 110;
		      /*if there's a max output size, and the custom zlib returned error, then indicate that error instead*/
		      if(settings.max_output_size != 0 && *outsize > settings.max_output_size) error = 109;
		    }
		  } else {
		    ucvector v = ucvector_init(*_out, *outsize);
		    if(expected_size != 0) {
		      /*reserve the memory to avoid intermediate reallocations*/
		      ucvector_resize(&v, *outsize + expected_size);
		      v.size = *outsize;
		    }
		    error = lodepng_zlib_decompressv(&v, _in, insize, settings);
		    *_out = v.data;
		    *outsize = v.size;
		  }
		  return error;
		}

#endif /*LODEPNG_COMPILE_DECODER*/

#if LODEPNG_COMPILE_ENCODER

		unsigned lodepng_zlib_compress(uint8** out, size_t* outsize, const uint8* in,
		                               size_t insize, const LodePNGCompressSettings* settings) {
		  size_t i;
		  unsigned error;
		  uint8* deflatedata = 0;
		  size_t deflatesize = 0;

		  error = deflate(&deflatedata, &deflatesize, in, insize, settings);

		  *out = NULL;
		  *outsize = 0;
		  if(!error) {
		    *outsize = deflatesize + 6;
		    *out = (uint8*)lodepng_malloc(*outsize);
		    if(!*out) error = 83; /*alloc fail*/
		  }

		  if(!error) {
		    unsigned ADLER32 = adler32(in, (unsigned)insize);
		    /*zlib data: 1 byte CMF (CM+CINFO), 1 byte FLG, deflate data, 4 byte ADLER32 checksum of the Decompressed data*/
		    unsigned CMF = 120; /*0b01111000: CM 8, CINFO 7. With CINFO 7, any window size up to 32768 can be used.*/
		    unsigned FLEVEL = 0;
		    unsigned FDICT = 0;
		    unsigned CMFFLG = 256 * CMF + FDICT * 32 + FLEVEL * 64;
		    unsigned FCHECK = 31 - CMFFLG % 31;
		    CMFFLG += FCHECK;

		    (*out)[0] = (uint8)(CMFFLG >> 8);
		    (*out)[1] = (uint8)(CMFFLG & 255);
		    for(i = 0; i != deflatesize; ++i) (*out)[i + 2] = deflatedata[i];
		    lodepng_set32bitInt(&(*out)[*outsize - 4], ADLER32);
		  }

		  lodepng_free(deflatedata);
		  return error;
		}

		/* compress using the default or custom zlib function */
		static unsigned zlib_compress(uint8** out, size_t* outsize, const uint8* in,
		                              size_t insize, const LodePNGCompressSettings* settings) {
		  if(settings.custom_zlib) {
		    unsigned error = settings.custom_zlib(out, outsize, in, insize, settings);
		    /*the custom zlib is allowed to have its own error codes, however, we translate it to code 111*/
		    return error ? 111 : 0;
		  } else {
		    return lodepng_zlib_compress(out, outsize, in, insize, settings);
		  }
		}

#endif /*LODEPNG_COMPILE_ENCODER*/

#else /*no LODEPNG_COMPILE_ZLIB*/

#if LODEPNG_COMPILE_DECODER
		static unsigned zlib_decompress(uint8** _out, size_t* outsize, size_t expected_size,
		                                uint8* _in, size_t insize, LodePNGDecompressSettings* settings) {
		  if(settings.custom_zlib == null) return 87; /*no custom zlib function provided */
		  (void)expected_size;
		  return settings.custom_zlib(_out, outsize, _in, insize, settings);
		}
#endif /*LODEPNG_COMPILE_DECODER*/
#if LODEPNG_COMPILE_ENCODER
		static unsigned zlib_compress(uint8** out, size_t* outsize, const uint8* in,
		                              size_t insize, const LodePNGCompressSettings* settings) {
		  if(!settings.custom_zlib) return 87; /*no custom zlib function provided */
		  return settings.custom_zlib(out, outsize, in, insize, settings);
		}
#endif /*LODEPNG_COMPILE_ENCODER*/

#endif /*LODEPNG_COMPILE_ZLIB*/

		/* ////////////////////////////////////////////////////////////////////////// */

#if LODEPNG_COMPILE_ENCODER

		/*this is a good tradeoff between speed and compression ratio*/
#define DEFAULT_WINDOWSIZE 2048

		void lodepng_compress_settings_init(LodePNGCompressSettings* settings) {
		  /*compress with dynamic huffman tree (not in the mathematical sense, just not the predefined one)*/
		  settings.btype = 2;
		  settings.use_lz77 = 1;
		  settings.windowsize = DEFAULT_WINDOWSIZE;
		  settings.minmatch = 3;
		  settings.nicematch = 128;
		  settings.lazymatching = 1;

		  settings.custom_zlib = 0;
		  settings.custom_deflate = 0;
		  settings.custom_context = 0;
		}

		const LodePNGCompressSettings lodepng_default_compress_settings = {2, 1, DEFAULT_WINDOWSIZE, 3, 128, 1, 0, 0, 0};


#endif /*LODEPNG_COMPILE_ENCODER*/

#if LODEPNG_COMPILE_DECODER

		static void lodepng_decompress_settings_init(LodePNGDecompressSettings* settings) {
		  settings.ignore_adler32 = 0;
		  settings.ignore_nlen = 0;
		  settings.max_output_size = 0;

		  settings.custom_zlib = 0;
		  settings.custom_inflate = 0;
		  settings.custom_context = null;
		}

		static LodePNGDecompressSettings lodepng_default_decompress_settings = LodePNGDecompressSettings(0, 0, 0);

#endif /*LODEPNG_COMPILE_DECODER*/

		/* ////////////////////////////////////////////////////////////////////////// */
		/* ////////////////////////////////////////////////////////////////////////// */
		/* // End of Zlib related code. Begin of PNG related code.                 // */
		/* ////////////////////////////////////////////////////////////////////////// */
		/* ////////////////////////////////////////////////////////////////////////// */

#if LODEPNG_COMPILE_PNG

		/* ////////////////////////////////////////////////////////////////////////// */
		/* / CRC32                                                                  / */
		/* ////////////////////////////////////////////////////////////////////////// */


#if !LODEPNG_NO_COMPILE_CRC
		/* CRC polynomial: 0xedb88320 */
		const unsigned[256] lodepng_crc32_table = .(
		           0u, 1996959894u, 3993919788u, 2567524794u,  124634137u, 1886057615u, 3915621685u, 2657392035u,
		   249268274u, 2044508324u, 3772115230u, 2547177864u,  162941995u, 2125561021u, 3887607047u, 2428444049u,
		   498536548u, 1789927666u, 4089016648u, 2227061214u,  450548861u, 1843258603u, 4107580753u, 2211677639u,
		   325883990u, 1684777152u, 4251122042u, 2321926636u,  335633487u, 1661365465u, 4195302755u, 2366115317u,
		   997073096u, 1281953886u, 3579855332u, 2724688242u, 1006888145u, 1258607687u, 3524101629u, 2768942443u,
		   901097722u, 1119000684u, 3686517206u, 2898065728u,  853044451u, 1172266101u, 3705015759u, 2882616665u,
		   651767980u, 1373503546u, 3369554304u, 3218104598u,  565507253u, 1454621731u, 3485111705u, 3099436303u,
		   671266974u, 1594198024u, 3322730930u, 2970347812u,  795835527u, 1483230225u, 3244367275u, 3060149565u,
		  1994146192u,   31158534u, 2563907772u, 4023717930u, 1907459465u,  112637215u, 2680153253u, 3904427059u,
		  2013776290u,  251722036u, 2517215374u, 3775830040u, 2137656763u,  141376813u, 2439277719u, 3865271297u,
		  1802195444u,  476864866u, 2238001368u, 4066508878u, 1812370925u,  453092731u, 2181625025u, 4111451223u,
		  1706088902u,  314042704u, 2344532202u, 4240017532u, 1658658271u,  366619977u, 2362670323u, 4224994405u,
		  1303535960u,  984961486u, 2747007092u, 3569037538u, 1256170817u, 1037604311u, 2765210733u, 3554079995u,
		  1131014506u,  879679996u, 2909243462u, 3663771856u, 1141124467u,  855842277u, 2852801631u, 3708648649u,
		  1342533948u,  654459306u, 3188396048u, 3373015174u, 1466479909u,  544179635u, 3110523913u, 3462522015u,
		  1591671054u,  702138776u, 2966460450u, 3352799412u, 1504918807u,  783551873u, 3082640443u, 3233442989u,
		  3988292384u, 2596254646u,   62317068u, 1957810842u, 3939845945u, 2647816111u,   81470997u, 1943803523u,
		  3814918930u, 2489596804u,  225274430u, 2053790376u, 3826175755u, 2466906013u,  167816743u, 2097651377u,
		  4027552580u, 2265490386u,  503444072u, 1762050814u, 4150417245u, 2154129355u,  426522225u, 1852507879u,
		  4275313526u, 2312317920u,  282753626u, 1742555852u, 4189708143u, 2394877945u,  397917763u, 1622183637u,
		  3604390888u, 2714866558u,  953729732u, 1340076626u, 3518719985u, 2797360999u, 1068828381u, 1219638859u,
		  3624741850u, 2936675148u,  906185462u, 1090812512u, 3747672003u, 2825379669u,  829329135u, 1181335161u,
		  3412177804u, 3160834842u,  628085408u, 1382605366u, 3423369109u, 3138078467u,  570562233u, 1426400815u,
		  3317316542u, 2998733608u,  733239954u, 1555261956u, 3268935591u, 3050360625u,  752459403u, 1541320221u,
		  2607071920u, 3965973030u, 1969922972u,   40735498u, 2617837225u, 3943577151u, 1913087877u,   83908371u,
		  2512341634u, 3803740692u, 2075208622u,  213261112u, 2463272603u, 3855990285u, 2094854071u,  198958881u,
		  2262029012u, 4057260610u, 1759359992u,  534414190u, 2176718541u, 4139329115u, 1873836001u,  414664567u,
		  2282248934u, 4279200368u, 1711684554u,  285281116u, 2405801727u, 4167216745u, 1634467795u,  376229701u,
		  2685067896u, 3608007406u, 1308918612u,  956543938u, 2808555105u, 3495958263u, 1231636301u, 1047427035u,
		  2932959818u, 3654703836u, 1088359270u,  936918000u, 2847714899u, 3736837829u, 1202900863u,  817233897u,
		  3183342108u, 3401237130u, 1404277552u,  615818150u, 3134207493u, 3453421203u, 1423857449u,  601450431u,
		  3009837614u, 3294710456u, 1567103746u,  711928724u, 3020668471u, 3272380065u, 1510334235u,  755167117u
		);

		/*Return the CRC of the bytes buf[0..len-1].*/
		static unsigned lodepng_crc32(uint8* data, size_t length) {
		  unsigned r = 0xffffffffu;
		  size_t i;
		  for(i = 0; i < length; ++i) {
		    r = lodepng_crc32_table[(r ^ data[i]) & 0xffu] ^ (r >> 8u);
		  }
		  return r ^ 0xffffffffu;
		}
#else /* !LODEPNG_NO_COMPILE_CRC */
		unsigned lodepng_crc32(uint8* data, size_t length){return default;}
#endif /* !LODEPNG_NO_COMPILE_CRC */

		/* ////////////////////////////////////////////////////////////////////////// */
		/* / Reading and writing PNG color channel bits                             / */
		/* ////////////////////////////////////////////////////////////////////////// */

		/* The color channel bits of less-than-8-bit pixels are read with the MSB of bytes first,
		so LodePNGBitWriter and LodePNGBitReader can't be used for those. */

		static uint8 readBitFromReversedStream(size_t* bitpointer, uint8* bitstream) {
		  uint8 result = (uint8)((bitstream[(*bitpointer) >> 3] >> (7 - ((*bitpointer) & 0x7))) & 1);
		  ++(*bitpointer);
		  return result;
		}

		/* TODO: make this faster */
		static unsigned readBitsFromReversedStream(size_t* bitpointer, uint8* bitstream, size_t nbits) {
		  unsigned result = 0;
		  size_t i;
		  for(i = 0 ; i < nbits; ++i) {
		    result <<= 1u;
		    result |= (unsigned)readBitFromReversedStream(bitpointer, bitstream);
		  }
		  return result;
		}

		static void setBitOfReversedStream(size_t* bitpointer, uint8* bitstream, uint8 bit) {
		  /*the current bit in bitstream may be 0 or 1 for this to work*/
		  if(bit == 0) bitstream[(*bitpointer) >> 3u] &=  (uint8)(~(1u << (7u - ((*bitpointer) & 7u))));
		  else         bitstream[(*bitpointer) >> 3u] |=  (1u << (7u - ((*bitpointer) & 7u)));
		  ++(*bitpointer);
		}

		/* ////////////////////////////////////////////////////////////////////////// */
		/* / PNG chunks                                                             / */
		/* ////////////////////////////////////////////////////////////////////////// */

		static unsigned lodepng_chunk_length(uint8* chunk) {
		  return lodepng_read32bitInt(&chunk[0]);
		}

		static void lodepng_chunk_type(ref char8[5] type, uint8* chunk) {
		  unsigned i;
		  for(i = 0; i != 4; ++i) type[i] = (char8)chunk[4 + i];
		  type[4] = 0; /*null termination char*/
		}

		static bool lodepng_chunk_type_equals(uint8* chunk, char8* type) {
		  if(lodepng_strlen(type) != 4) return false;
		  return (chunk[4] == type[0] && chunk[5] == type[1] && chunk[6] == type[2] && chunk[7] == type[3]);
		}

		static bool lodepng_chunk_ancillary(uint8* chunk) {
		  return((chunk[4] & 32) != 0);
		}

		static bool lodepng_chunk_private(uint8* chunk) {
		  return((chunk[6] & 32) != 0);
		}

		static bool lodepng_chunk_safetocopy(uint8* chunk) {
		  return((chunk[7] & 32) != 0);
		}

		static uint8* lodepng_chunk_data(uint8* chunk) {
		  return &chunk[8];
		}

		static uint8* lodepng_chunk_data_const(uint8* chunk) {
		  return &chunk[8];
		}

		static bool lodepng_chunk_check_crc(uint8* chunk) {
		  unsigned length = lodepng_chunk_length(chunk);
		  unsigned CRC = lodepng_read32bitInt(&chunk[length + 8]);
		  /*the CRC is taken of the data and the 4 chunk type letters, not the length*/
		  unsigned checksum = lodepng_crc32(&chunk[4], length + 4);
		  if(CRC != checksum) return true;
		  else return false;
		}

		static void lodepng_chunk_generate_crc(uint8* chunk) {
		  unsigned length = lodepng_chunk_length(chunk);
		  unsigned CRC = lodepng_crc32(&chunk[4], length + 4);
		  lodepng_set32bitInt(chunk + 8 + length, CRC);
		}

		static uint8* lodepng_chunk_next(uint8* chunk, uint8* end) {
		  if(chunk >= end || end - chunk < 12) return end; /*too small to contain a chunk*/
		  if(chunk[0] == 0x89 && chunk[1] == 0x50 && chunk[2] == 0x4e && chunk[3] == 0x47
		    && chunk[4] == 0x0d && chunk[5] == 0x0a && chunk[6] == 0x1a && chunk[7] == 0x0a) {
		    /* Is PNG magic header at start of PNG file. Jump to first actual chunk. */
		    return chunk + 8;
		  } else {
		    size_t total_chunk_length = default;
		    uint8* result;
		    if(lodepng_addofl(lodepng_chunk_length(chunk), 12, &total_chunk_length)) return end;
		    result = chunk + total_chunk_length;
		    if(result < chunk) return end; /*pointer overflow*/
		    return result;
		  }
		}

		static uint8* lodepng_chunk_next_const(uint8* chunk, uint8* end) {
		  if(chunk >= end || end - chunk < 12) return end; /*too small to contain a chunk*/
		  if(chunk[0] == 0x89 && chunk[1] == 0x50 && chunk[2] == 0x4e && chunk[3] == 0x47
		    && chunk[4] == 0x0d && chunk[5] == 0x0a && chunk[6] == 0x1a && chunk[7] == 0x0a) {
		    /* Is PNG magic header at start of PNG file. Jump to first actual chunk. */
		    return chunk + 8;
		  } else {
		    size_t total_chunk_length = default;
		    uint8* result;
		    if(lodepng_addofl(lodepng_chunk_length(chunk), 12, &total_chunk_length)) return end;
		    result = chunk + total_chunk_length;
		    if(result < chunk) return end; /*pointer overflow*/
		    return result;
		  }
		}

		static uint8* lodepng_chunk_find(uint8* chunk, uint8* end, char8[5] type) {
			var chunk;
		  for(;;) {
		    if(chunk >= end || end - chunk < 12) return null; /* past file end: chunk + 12 > end */
		    if(lodepng_chunk_type_equals(chunk, &type[0])) return chunk;
		    chunk = lodepng_chunk_next(chunk, end);
		  }
		}

		static uint8* lodepng_chunk_find_const(uint8* chunk, uint8* end, char8[5] type) {
			var chunk;
		  for(;;) {
		    if(chunk >= end || end - chunk < 12) return null; /* past file end: chunk + 12 > end */
		    if(lodepng_chunk_type_equals(chunk, &type[0])) return chunk;
		    chunk = lodepng_chunk_next_const(chunk, end);
		  }
		}

		static unsigned lodepng_chunk_append(uint8** _out, size_t* outsize, uint8* chunk) {
		  unsigned i;
		  size_t total_chunk_length = default, new_length = default;
		  uint8* chunk_start, new_buffer;

		  if(lodepng_addofl(lodepng_chunk_length(chunk), 12, &total_chunk_length)) return 77;
		  if(lodepng_addofl(*outsize, total_chunk_length, &new_length)) return 77;

		  new_buffer = (uint8*)lodepng_realloc(*_out, *outsize, new_length);
		  if(new_buffer == null) return 83; /*alloc fail*/
		  (*_out) = new_buffer;
		  (*outsize) = new_length;
		  chunk_start = &(*_out)[new_length - total_chunk_length];

		  for(i = 0; i != total_chunk_length; ++i) chunk_start[i] = chunk[i];

		  return 0;
		}

		/*Sets length and name and allocates the space for data and crc but does not
		set data or crc yet. Returns the start of the chunk in chunk. The start of
		the data is at chunk + 8. To finalize chunk, add the data, then use
		lodepng_chunk_generate_crc */
		static unsigned lodepng_chunk_init(uint8** chunk,
		                                   ucvector* _out,
		                                   unsigned length, char8* type) {
		  size_t new_length = _out.size;
		  if(lodepng_addofl(new_length, length, &new_length)) return 77;
		  if(lodepng_addofl(new_length, 12, &new_length)) return 77;
		  if(!ucvector_resize(_out, new_length)) return 83; /*alloc fail*/
		  *chunk = _out.data + new_length - length - 12u;

		  /*1: length*/
		  lodepng_set32bitInt(*chunk, length);

		  /*2: chunk name (4 letters)*/
		  lodepng_memcpy(*chunk + 4, type, 4);

		  return 0;
		}

		/* like lodepng_chunk_create but with custom allocsize */
		static unsigned lodepng_chunk_createv(ucvector* _out,
		                                      unsigned length, char8* type, uint8* data) {
		  uint8* chunk = default;
		  CERROR_TRY_RETURN!(lodepng_chunk_init(&chunk, _out, length, type));

		  /*3: the data*/
		  lodepng_memcpy(chunk + 8, data, length);

		  /*4: CRC (of the chunkname characters and the data)*/
		  lodepng_chunk_generate_crc(chunk);

		  return 0;
		}

		static unsigned lodepng_chunk_create(uint8** _out, size_t* outsize,
		                              unsigned length, char8* type, uint8* data) {
		  ucvector v = ucvector_init(*_out, *outsize);
		  unsigned error = lodepng_chunk_createv(&v, length, type, data);
		  *_out = v.data;
		  *outsize = v.size;
		  return error;
		}

		/* ////////////////////////////////////////////////////////////////////////// */
		/* / Color types, channels, bits                                            / */
		/* ////////////////////////////////////////////////////////////////////////// */

		/*checks if the colortype is valid and the bitdepth bd is allowed for this colortype.
		Return value is a LodePNG error code.*/
		static unsigned checkColorValidity(LodePNGColorType colortype, unsigned bd) {
		  switch(colortype) {
		    case .LCT_GREY:       if(!(bd == 1 || bd == 2 || bd == 4 || bd == 8 || bd == 16)) return 37; break;
		    case .LCT_RGB:        if(!(                                 bd == 8 || bd == 16)) return 37; break;
		    case .LCT_PALETTE:    if(!(bd == 1 || bd == 2 || bd == 4 || bd == 8            )) return 37; break;
		    case .LCT_GREY_ALPHA: if(!(                                 bd == 8 || bd == 16)) return 37; break;
		    case .LCT_RGBA:       if(!(                                 bd == 8 || bd == 16)) return 37; break;
		    case .LCT_MAX_OCTET_VALUE: return 31; /* invalid color type */
		    default: return 31; /* invalid color type */
		  }
		  return 0; /*allowed color type / bits combination*/
		}

		static unsigned getNumColorChannels(LodePNGColorType colortype) {
		  switch(colortype) {
		    case .LCT_GREY: return 1;
		    case .LCT_RGB: return 3;
		    case .LCT_PALETTE: return 1;
		    case .LCT_GREY_ALPHA: return 2;
		    case .LCT_RGBA: return 4;
		    case .LCT_MAX_OCTET_VALUE: return 0; /* invalid color type */
		    default: return 0; /*invalid color type*/
		  }
		}

		static unsigned lodepng_get_bpp_lct(LodePNGColorType colortype, unsigned bitdepth) {
		  /*bits per pixel is amount of channels * bits per channel*/
		  return getNumColorChannels(colortype) * bitdepth;
		}

		/* ////////////////////////////////////////////////////////////////////////// */

		#if LODEPNG_COMPILE_DECODER
		/*Settings for zlib decompression*/
		struct LodePNGDecompressSettings {
		  /* Check LodePNGDecoderSettings for more ignorable errors such as ignore_crc */
		  public unsigned ignore_adler32; /*if 1, continue and don't give an error message if the Adler32 checksum is corrupted*/
		  public unsigned ignore_nlen; /*ignore complement of len checksum in uncompressed blocks*/

		  /*Maximum decompressed size, beyond this the decoder may (and is encouraged to) stop decoding,
		  return an error, output a data size > max_output_size and all the data up to that point. This is
		  not hard limit nor a guarantee, but can prevent excessive memory usage. This setting is
		  ignored by the PNG decoder, but is used by the deflate/zlib decoder and can be used by custom ones.
		  Set to 0 to impose no limit (the default).*/
		  public size_t max_output_size;


		/*
			/*use custom zlib decoder instead of built in one (default: null).
			Should return 0 if success, any non-0 if error (numeric value not exposed).*/
			public function unsigned(List<uint8>, Span<uint8>, ref LodePNGDecompressSettings) custom_zlib;
			/*use custom deflate decoder instead of built in one (default: null)
			if custom_zlib is not null, custom_inflate is ignored (the zlib format uses deflate).
			Should return 0 if success, any non-0 if error (numeric value not exposed).*/
			public function unsigned(List<uint8>, Span<uint8>, ref LodePNGDecompressSettings) custom_inflate;
			*/

		  /*use custom zlib decoder instead of built in one (default: null).
		  Should return 0 if success, any non-0 if error (numeric value not exposed).*/
		  public function unsigned (uint8**, size_t*,
		                          uint8*, size_t,
		                          LodePNGDecompressSettings*) custom_zlib;
		  /*use custom deflate decoder instead of built in one (default: null)
		  if custom_zlib is not null, custom_inflate is ignored (the zlib format uses deflate).
		  Should return 0 if success, any non-0 if error (numeric value not exposed).*/
		  public function unsigned (uint8**, size_t*,
		                             uint8*, size_t,
		                             LodePNGDecompressSettings*) custom_inflate;

		  public void* custom_context; /*optional custom settings for custom functions*/

			public this(unsigned ignore_adler32, unsigned ignore_nlen, unsigned max_output_size){
				this.ignore_adler32 = ignore_adler32;
				this.ignore_nlen = ignore_nlen;
				this.max_output_size = max_output_size;

				custom_zlib = null;
				custom_inflate = null;
				custom_context = null;
			}
		};

#endif /*LODEPNG_COMPILE_DECODER*/

		#if LODEPNG_COMPILE_DECODER
		/*
		Settings for the decoder. This contains settings for the PNG and the Zlib
		decoder, but not the Info settings from the Info structs.
		*/
		struct LodePNGDecoderSettings {
		  public LodePNGDecompressSettings zlibsettings; /*in here is the setting to ignore Adler32 checksums*/

		  /* Check LodePNGDecompressSettings for more ignorable errors such as ignore_adler32 */
		  public unsigned ignore_crc; /*ignore CRC checksums*/
		  public unsigned ignore_critical; /*ignore unknown critical chunks*/
		  public unsigned ignore_end; /*ignore issues at end of file if possible (missing IEND chunk, too large chunk, ...)*/
		  /* TODO: make a system involving warnings with levels and a strict mode instead. Other potentially recoverable
		     errors: srgb rendering intent value, size of content of ancillary chunks, more than 79 characters for some
		     strings, placement/combination rules for ancillary chunks, crc of unknown chunks, allowed characters
		     in string keys, etc... */

		  public unsigned color_convert; /*whether to convert the PNG to the color type you want. Default: yes*/

#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		  public unsigned read_text_chunks; /*if false but remember_unknown_chunks is true, they're stored in the unknown chunks*/

		  /*store all bytes from unknown chunks in the LodePNGInfo (off by default, useful for a png editor)*/
		  public unsigned remember_unknown_chunks;

		  /* maximum size for decompressed text chunks. If a text chunk's text is larger than this, an error is returned,
		  unless reading text chunks is disabled or this limit is set higher or disabled. Set to 0 to allow any size.
		  By default it is a value that prevents unreasonably large strings from hogging memory. */
		  public size_t max_text_size;

		  /* maximum size for compressed ICC chunks. If the ICC profile is larger than this, an error will be returned. Set to
		  0 to allow any size. By default this is a value that prevents ICC profiles that would be much larger than any
		  legitimate profile could be to hog memory. */
		  public size_t max_icc_size;
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
		}// LodePNGDecoderSettings;

#endif /*LODEPNG_COMPILE_DECODER*/


		/*The settings, state and information for extended encoding and decoding.*/
		struct LodePNGState {
#if LODEPNG_COMPILE_DECODER
		  public LodePNGDecoderSettings decoder; /*the decoding settings*/
#endif /*LODEPNG_COMPILE_DECODER*/
#if LODEPNG_COMPILE_ENCODER
		  public LodePNGEncoderSettings encoder; /*the encoding settings*/
#endif /*LODEPNG_COMPILE_ENCODER*/
		  public LodePNGColorMode info_raw; /*specifies the format in which you would like to get the raw pixel buffer*/
		  public LodePNGInfo info_png; /*info of the PNG image obtained after decoding*/
		  public unsigned error;
		}

		/*Information about the PNG image, except pixels, width and height.*/
		struct LodePNGInfo {
		  /*header (IHDR), palette (PLTE) and transparency (tRNS) chunks*/
		  public unsigned compression_method;/*compression method of the original file. Always 0.*/
		  public unsigned filter_method;     /*filter method of the original file*/
		  public unsigned interlace_method;  /*interlace method of the original file: 0=none, 1=Adam7*/
		  public LodePNGColorMode color;     /*color type and bits, palette and transparency of the PNG file*/

#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		  /*
		  Suggested background color chunk (bKGD)
		  This uses the same color mode and bit depth as the PNG (except no alpha channel),
		  with values truncated to the bit depth in the unsigned integer.
		  For grayscale and palette PNGs, the value is stored in background_r. The values
		  in background_g and background_b are then unused.
		  So when decoding, you may get these in a different color mode than the one you requested
		  for the raw pixels.
		  When encoding with auto_convert, you must use the color model defined in info_png.color for
		  these values. The encoder normally ignores info_png.color when auto_convert is on, but will
		  use it to interpret these values (and convert copies of them to its chosen color model).
		  When encoding, avoid setting this to an expensive color, such as a non-gray value
		  when the image is gray, or the compression will be worse since it will be forced to
		  write the PNG with a more expensive color mode (when auto_convert is on).
		  The decoder does not use this background color to edit the color of pixels. This is a
		  completely optional metadata feature.
		  */
		  unsigned background_defined; /*is a suggested background color given?*/
		  unsigned background_r;       /*red/gray/palette component of suggested background color*/
		  unsigned background_g;       /*green component of suggested background color*/
		  unsigned background_b;       /*blue component of suggested background color*/

		  /*
		  Non-international text chunks (tEXt and zTXt)
		  The char** arrays each contain num strings. The actual messages are in
		  text_strings, while text_keys are keywords that give a short description what
		  the actual text represents, e.g. Title, Author, Description, or anything else.
		  All the string fields below including strings, keys, names and language tags are null terminated.
		  The PNG specification uses null characters for the keys, names and tags, and forbids null
		  characters to appear in the main text which is why we can use null termination everywhere here.
		  A keyword is minimum 1 character and maximum 79 characters long (plus the
		  additional null terminator). It's discouraged to use a single line length
		  longer than 79 characters for texts.
		  Don't allocate these text buffers yourself. Use the init/cleanup functions
		  correctly and use lodepng_add_text and lodepng_clear_text.
		  Standard text chunk keywords and strings are encoded using Latin-1.
		  */
		  size_t text_num; /*the amount of texts in these char** buffers (there may be more texts in itext)*/
		  char8** text_keys; /*the keyword of a text chunk (e.g. "Comment")*/
		  char8** text_strings; /*the actual text*/

		  /*
		  International text chunks (iTXt)
		  Similar to the non-international text chunks, but with additional strings
		  "langtags" and "transkeys", and the following text encodings are used:
		  keys: Latin-1, langtags: ASCII, transkeys and strings: UTF-8.
		  keys must be 1-79 characters (plus the additional null terminator), the other
		  strings are any length.
		  */
		  size_t itext_num; /*the amount of international texts in this PNG*/
		  char8** itext_keys; /*the English keyword of the text chunk (e.g. "Comment")*/
		  char8** itext_langtags; /*language tag for this text's language, ISO/IEC 646 string, e.g. ISO 639 language tag*/
		  char8** itext_transkeys; /*keyword translated to the international language - UTF-8 string*/
		  char8** itext_strings; /*the actual international text - UTF-8 string*/

		  /*time chunk (tIME)*/
		  unsigned time_defined; /*set to 1 to make the encoder generate a tIME chunk*/
		  LodePNGTime time;

		  /*phys chunk (pHYs)*/
		  unsigned phys_defined; /*if 0, there is no pHYs chunk and the values below are undefined, if 1 else there is one*/
		  unsigned phys_x; /*pixels per unit in x direction*/
		  unsigned phys_y; /*pixels per unit in y direction*/
		  unsigned phys_unit; /*may be 0 (unknown unit) or 1 (metre)*/

		  /*
		  Color profile related chunks: gAMA, cHRM, sRGB, iCPP
		  LodePNG does not apply any color conversions on pixels in the encoder or decoder and does not interpret these color
		  profile values. It merely passes on the information. If you wish to use color profiles and convert colors, please
		  use these values with a color management library.
		  See the PNG, ICC and sRGB specifications for more information about the meaning of these values.
		  */

		  /* gAMA chunk: optional, overridden by sRGB or iCCP if those are present. */
		  unsigned gama_defined; /* Whether a gAMA chunk is present (0 = not present, 1 = present). */
		  unsigned gama_gamma;   /* Gamma exponent times 100000 */

		  /* cHRM chunk: optional, overridden by sRGB or iCCP if those are present. */
		  unsigned chrm_defined; /* Whether a cHRM chunk is present (0 = not present, 1 = present). */
		  unsigned chrm_white_x; /* White Point x times 100000 */
		  unsigned chrm_white_y; /* White Point y times 100000 */
		  unsigned chrm_red_x;   /* Red x times 100000 */
		  unsigned chrm_red_y;   /* Red y times 100000 */
		  unsigned chrm_green_x; /* Green x times 100000 */
		  unsigned chrm_green_y; /* Green y times 100000 */
		  unsigned chrm_blue_x;  /* Blue x times 100000 */
		  unsigned chrm_blue_y;  /* Blue y times 100000 */

		  /*
		  sRGB chunk: optional. May not appear at the same time as iCCP.
		  If gAMA is also present gAMA must contain value 45455.
		  If cHRM is also present cHRM must contain respectively 31270,32900,64000,33000,30000,60000,15000,6000.
		  */
		  unsigned srgb_defined; /* Whether an sRGB chunk is present (0 = not present, 1 = present). */
		  unsigned srgb_intent;  /* Rendering intent: 0=perceptual, 1=rel. colorimetric, 2=saturation, 3=abs. colorimetric */

		  /*
		  iCCP chunk: optional. May not appear at the same time as sRGB.
		  LodePNG does not parse or use the ICC profile (except its color space header field for an edge case), a
		  separate library to handle the ICC data (not included in LodePNG) format is needed to use it for color
		  management and conversions.
		  For encoding, if iCCP is present, gAMA and cHRM are recommended to be added as well with values that match the ICC
		  profile as closely as possible, if you wish to do this you should provide the correct values for gAMA and cHRM and
		  enable their '_defined' flags since LodePNG will not automatically compute them from the ICC profile.
		  For encoding, the ICC profile is required by the PNG specification to be an "RGB" profile for non-gray
		  PNG color types and a "GRAY" profile for gray PNG color types. If you disable auto_convert, you must ensure
		  the ICC profile type matches your requested color type, else the encoder gives an error. If auto_convert is
		  enabled (the default), and the ICC profile is not a good match for the pixel data, this will result in an encoder
		  error if the pixel data has non-gray pixels for a GRAY profile, or a silent less-optimal compression of the pixel
		  data if the pixels could be encoded as grayscale but the ICC profile is RGB.
		  To avoid this do not set an ICC profile in the image unless there is a good reason for it, and when doing so
		  make sure you compute it carefully to avoid the above problems.
		  */
		  unsigned iccp_defined;      /* Whether an iCCP chunk is present (0 = not present, 1 = present). */
		  char8* iccp_name;            /* Null terminated string with profile name, 1-79 bytes */
		  /*
		  The ICC profile in iccp_profile_size bytes.
		  Don't allocate this buffer yourself. Use the init/cleanup functions
		  correctly and use lodepng_set_icc and lodepng_clear_icc.
		  */
		  uint8* iccp_profile;
		  unsigned iccp_profile_size; /* The size of iccp_profile in bytes */

		  /* End of color profile related chunks */


		  /*
		  unknown chunks: chunks not known by LodePNG, passed on byte for byte.
		  There are 3 buffers, one for each position in the PNG where unknown chunks can appear.
		  Each buffer contains all unknown chunks for that position consecutively.
		  The 3 positions are:
		  0: between IHDR and PLTE, 1: between PLTE and IDAT, 2: between IDAT and IEND.
		  For encoding, do not store critical chunks or known chunks that are enabled with a "_defined" flag
		  above in here, since the encoder will blindly follow this and could then encode an invalid PNG file
		  (such as one with two IHDR chunks or the disallowed combination of sRGB with iCCP). But do use
		  this if you wish to store an ancillary chunk that is not supported by LodePNG (such as sPLT or hIST),
		  or any non-standard PNG chunk.
		  Do not allocate or traverse this data yourself. Use the chunk traversing functions declared
		  later, such as lodepng_chunk_next and lodepng_chunk_append, to read/write this struct.
		  */
		  uint8*[3] unknown_chunks_data;
		  size_t[3] unknown_chunks_size; /*size in bytes of the unknown chunks, given for protection*/
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
		}

		public enum LodePNGColorType {
		  LCT_GREY = 0, /*grayscale: 1,2,4,8,16 bit*/
		  LCT_RGB = 2, /*RGB: 8,16 bit*/
		  LCT_PALETTE = 3, /*palette: 1,2,4,8 bit*/
		  LCT_GREY_ALPHA = 4, /*grayscale with alpha: 8,16 bit*/
		  LCT_RGBA = 6, /*RGB with alpha: 8,16 bit*/
		  /*LCT_MAX_OCTET_VALUE lets the compiler allow this enum to represent any invalid
		  byte value from 0 to 255 that could be present in an invalid PNG file header. Do
		  not use, compare with or set the name LCT_MAX_OCTET_VALUE, instead either use
		  the valid color type names above, or numeric values like 1 or 7 when checking for
		  particular disallowed color type byte values, or cast to integer to print it.*/
		  LCT_MAX_OCTET_VALUE = 255
		}

		struct LodePNGColorMode {
		  /*header (IHDR)*/
		  public LodePNGColorType colortype; /*color type, see PNG standard or documentation further in this header file*/
		  public unsigned bitdepth;  /*bits per sample, see PNG standard or documentation further in this header file*/

		  /*
		  palette (PLTE and tRNS)
		  Dynamically allocated with the colors of the palette, including alpha.
		  This field may not be allocated directly, use lodepng_color_mode_init first,
		  then lodepng_palette_add per color to correctly initialize it (to ensure size
		  of exactly 1024 bytes).
		  The alpha channels must be set as well, set them to 255 for opaque images.
		  When decoding, by default you can ignore this palette, since LodePNG already
		  fills the palette colors in the pixels of the raw RGBA output.
		  The palette is only supported for color type 3.
		  */
		  public uint8* palette; /*palette in RGBARGBA... order. Must be either 0, or when allocated must have 1024 bytes*/
		  public size_t palettesize; /*palette size in number of colors (amount of used bytes is 4 * palettesize)*/

		  /*
		  transparent color key (tRNS)
		  This color uses the same bit depth as the bitdepth value in this struct, which can be 1-bit to 16-bit.
		  For grayscale PNGs, r, g and b will all 3 be set to the same.
		  When decoding, by default you can ignore this information, since LodePNG sets
		  pixels with this key to transparent already in the raw RGBA output.
		  The color key is only supported for color types 0 and 2.
		  */
		  public bool key_defined; /*is a transparent color key given? 0 = false, 1 = true*/
		  public unsigned key_r;       /*red/grayscale component of color key*/
		  public unsigned key_g;       /*green component of color key*/
		  public unsigned key_b;       /*blue component of color key*/
		}

		static void lodepng_color_mode_init(LodePNGColorMode* info) {
		  info.key_defined = false;
		  info.key_r = info.key_g = info.key_b = 0;
		  info.colortype = .LCT_RGBA;
		  info.bitdepth = 8;
		  info.palette = default;
		  info.palettesize = 0;
		}

		/*allocates palette memory if needed, and initializes all colors to black*/
		static void lodepng_color_mode_alloc_palette(LodePNGColorMode* info) {
		  size_t i;
		  /*if the palette is already allocated, it will have size 1024 so no reallocation needed in that case*/
		  /*the palette must have room for up to 256 colors with 4 bytes each.*/
		  if(info.palette == null) info.palette = (uint8*)lodepng_malloc(1024);
		  if(info.palette == null) return; /*alloc fail*/
		  for(i = 0; i != 256; ++i) {
		    /*Initialize all unused colors with black, the value used for invalid palette indices.
		    This is an error according to the PNG spec, but common PNG decoders make it black instead.
		    That makes color conversion slightly faster due to no error handling needed.*/
		    info.palette[i * 4 + 0] = 0;
		    info.palette[i * 4 + 1] = 0;
		    info.palette[i * 4 + 2] = 0;
		    info.palette[i * 4 + 3] = 255;
		  }
		}

		static void lodepng_color_mode_cleanup(LodePNGColorMode* info) {
		  lodepng_palette_clear(info);
		}

		static unsigned lodepng_color_mode_copy(LodePNGColorMode* dest, LodePNGColorMode* source) {
		  lodepng_color_mode_cleanup(dest);
		  lodepng_memcpy(dest, source, sizeof(LodePNGColorMode));
		  if(source.palette != null) {
		    dest.palette = (uint8*)lodepng_malloc(1024);
		    if(dest.palette == null && source.palettesize > 0) return 83; /*alloc fail*/
		    lodepng_memcpy(dest.palette, source.palette, source.palettesize * 4);
		  }
		  return 0;
		}

		static LodePNGColorMode lodepng_color_mode_make(LodePNGColorType colortype, unsigned bitdepth) {
		  LodePNGColorMode result = default;
		  lodepng_color_mode_init(&result);
		  result.colortype = colortype;
		  result.bitdepth = bitdepth;
		  return result;
		}

		static bool lodepng_color_mode_equal(LodePNGColorMode* a, LodePNGColorMode* b) {
		  size_t i;
		  if(a.colortype != b.colortype) return false;
		  if(a.bitdepth != b.bitdepth) return false;
		  if(a.key_defined != b.key_defined) return false;
		  if(a.key_defined) {
		    if(a.key_r != b.key_r) return false;
		    if(a.key_g != b.key_g) return false;
		    if(a.key_b != b.key_b) return false;
		  }
		  if(a.palettesize != b.palettesize) return false;
		  for(i = 0; i != a.palettesize * 4; ++i) {
		    if(a.palette[i] != b.palette[i]) return false;
		  }
		  return true;
		}

		static void lodepng_palette_clear(LodePNGColorMode* info) {
		  if(info.palette != null) lodepng_free(info.palette);
		  info.palette = null;
		  info.palettesize = 0;
		}

		static unsigned lodepng_palette_add(LodePNGColorMode* info,
		                             uint8 r, uint8 g, uint8 b, uint8 a) {
		  if(info.palette == null) /*allocate palette if empty*/ {
		    lodepng_color_mode_alloc_palette(info);
		    if(info.palette == null) return 83; /*alloc fail*/
		  }
		  if(info.palettesize >= 256) {
		    return 108; /*too many palette values*/
		  }
		  info.palette[4 * info.palettesize + 0] = r;
		  info.palette[4 * info.palettesize + 1] = g;
		  info.palette[4 * info.palettesize + 2] = b;
		  info.palette[4 * info.palettesize + 3] = a;
		  ++info.palettesize;
		  return 0;
		}

		/*calculate bits per pixel out of colortype and bitdepth*/
		static unsigned lodepng_get_bpp(LodePNGColorMode* info) {
		  return lodepng_get_bpp_lct(info.colortype, info.bitdepth);
		}

		static unsigned lodepng_get_channels(LodePNGColorMode* info) {
		  return getNumColorChannels(info.colortype);
		}

		static bool lodepng_is_greyscale_type(LodePNGColorMode* info) {
		  return info.colortype == .LCT_GREY || info.colortype == .LCT_GREY_ALPHA;
		}

		static bool lodepng_is_alpha_type(LodePNGColorMode* info) {
		  return ((int)info.colortype & 4) != 0; /*4 or 6*/
		}

		static bool lodepng_is_palette_type(LodePNGColorMode* info) {
		  return info.colortype == .LCT_PALETTE;
		}

		static bool lodepng_has_palette_alpha(LodePNGColorMode* info) {
		  size_t i;
		  for(i = 0; i != info.palettesize; ++i) {
		    if(info.palette[i * 4 + 3] < 255) return true;
		  }
		  return false;
		}

		static bool lodepng_can_have_alpha(LodePNGColorMode* info) {
		  return info.key_defined
		      || lodepng_is_alpha_type(info)
		      || lodepng_has_palette_alpha(info);
		}

		static size_t lodepng_get_raw_size_lct(unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth) {
		  size_t bpp = lodepng_get_bpp_lct(colortype, bitdepth);
		  size_t n = (size_t)w * (size_t)h;
		  return ((n / 8u) * bpp) + ((n & 7u) * bpp + 7u) / 8u;
		}

		static size_t lodepng_get_raw_size(unsigned w, unsigned h, LodePNGColorMode* color) {
		  return lodepng_get_raw_size_lct(w, h, color.colortype, color.bitdepth);
		}


#if LODEPNG_COMPILE_PNG

		/*in an idat chunk, each scanline is a multiple of 8 bits, unlike the lodepng output buffer,
		and in addition has one extra byte per line: the filter byte. So this gives a larger
		result than lodepng_get_raw_size. Set h to 1 to get the size of 1 row including filter byte. */
		static size_t lodepng_get_raw_size_idat(unsigned w, unsigned h, unsigned bpp) {
		  /* + 1 for the filter byte, and possibly plus padding bits per line. */
		  /* Ignoring casts, the expression is equal to (w * bpp + 7) / 8 + 1, but avoids overflow of w * bpp */
		  size_t line = ((size_t)(w / 8u) * bpp) + 1u + ((w & 7u) * bpp + 7u) / 8u;
		  return (size_t)h * line;
		}

#if LODEPNG_COMPILE_DECODER
		/*Safely checks whether size_t overflow can be caused due to amount of pixels.
		This check is overcautious rather than precise. If this check indicates no overflow,
		you can safely compute in a size_t (but not an unsigned):
		-(size_t)w * (size_t)h * 8
		-amount of bytes in IDAT (including filter, padding and Adam7 bytes)
		-amount of bytes in raw color model
		Returns 1 if overflow possible, 0 if not.
		*/
		static bool lodepng_pixel_overflow(unsigned w, unsigned h,
		                                  LodePNGColorMode* pngcolor, LodePNGColorMode* rawcolor) {
		  size_t bpp = LODEPNG_MAX(lodepng_get_bpp(pngcolor), lodepng_get_bpp(rawcolor));
		  size_t numpixels = default, total;
		  size_t line = default; /* bytes per line in worst case */

		  if(lodepng_mulofl((size_t)w, (size_t)h, &numpixels)) return true;
		  if(lodepng_mulofl(numpixels, 8, &total)) return true; /* bit pointer with 8-bit color, or 8 bytes per channel color */

		  /* Bytes per scanline with the expression "(w / 8u) * bpp) + ((w & 7u) * bpp + 7u) / 8u" */
		  if(lodepng_mulofl((size_t)(w / 8u), bpp, &line)) return true;
		  if(lodepng_addofl(line, ((w & 7u) * bpp + 7u) / 8u, &line)) return true;

		  if(lodepng_addofl(line, 5, &line)) return true; /* 5 bytes overhead per line: 1 filterbyte, 4 for Adam7 worst case */
		  if(lodepng_mulofl(line, h, &total)) return true; /* Total bytes in worst case */

		  return false; /* no overflow */
		}
#endif /*LODEPNG_COMPILE_DECODER*/
#endif /*LODEPNG_COMPILE_PNG*/

#if LODEPNG_COMPILE_ANCILLARY_CHUNKS

		static void LodePNGUnknownChunks_init(LodePNGInfo* info) {
		  unsigned i;
		  for(i = 0; i != 3; ++i) info.unknown_chunks_data[i] = 0;
		  for(i = 0; i != 3; ++i) info.unknown_chunks_size[i] = 0;
		}

		static void LodePNGUnknownChunks_cleanup(LodePNGInfo* info) {
		  unsigned i;
		  for(i = 0; i != 3; ++i) lodepng_free(info.unknown_chunks_data[i]);
		}

		static unsigned LodePNGUnknownChunks_copy(LodePNGInfo* dest, const LodePNGInfo* src) {
		  unsigned i;

		  LodePNGUnknownChunks_cleanup(dest);

		  for(i = 0; i != 3; ++i) {
		    size_t j;
		    dest.unknown_chunks_size[i] = src.unknown_chunks_size[i];
		    dest.unknown_chunks_data[i] = (uint8*)lodepng_malloc(src.unknown_chunks_size[i]);
		    if(!dest.unknown_chunks_data[i] && dest.unknown_chunks_size[i]) return 83; /*alloc fail*/
		    for(j = 0; j < src.unknown_chunks_size[i]; ++j) {
		      dest.unknown_chunks_data[i][j] = src.unknown_chunks_data[i][j];
		    }
		  }

		  return 0;
		}

		/******************************************************************************/

		static void LodePNGText_init(LodePNGInfo* info) {
		  info.text_num = 0;
		  info.text_keys = NULL;
		  info.text_strings = NULL;
		}

		static void LodePNGText_cleanup(LodePNGInfo* info) {
		  size_t i;
		  for(i = 0; i != info.text_num; ++i) {
		    string_cleanup(&info.text_keys[i]);
		    string_cleanup(&info.text_strings[i]);
		  }
		  lodepng_free(info.text_keys);
		  lodepng_free(info.text_strings);
		}

		static unsigned LodePNGText_copy(LodePNGInfo* dest, const LodePNGInfo* source) {
		  size_t i = 0;
		  dest.text_keys = NULL;
		  dest.text_strings = NULL;
		  dest.text_num = 0;
		  for(i = 0; i != source.text_num; ++i) {
		    CERROR_TRY_RETURN(lodepng_add_text(dest, source.text_keys[i], source.text_strings[i]));
		  }
		  return 0;
		}

		static unsigned lodepng_add_text_sized(LodePNGInfo* info, const char* key, const char* str, size_t size) {
		  char** new_keys = (char**)(lodepng_realloc(info.text_keys, sizeof(char*) * (info.text_num + 1)));
		  char** new_strings = (char**)(lodepng_realloc(info.text_strings, sizeof(char*) * (info.text_num + 1)));

		  if(new_keys) info.text_keys = new_keys;
		  if(new_strings) info.text_strings = new_strings;

		  if(!new_keys || !new_strings) return 83; /*alloc fail*/

		  ++info.text_num;
		  info.text_keys[info.text_num - 1] = alloc_string(key);
		  info.text_strings[info.text_num - 1] = alloc_string_sized(str, size);
		  if(!info.text_keys[info.text_num - 1] || !info.text_strings[info.text_num - 1]) return 83; /*alloc fail*/

		  return 0;
		}

		unsigned lodepng_add_text(LodePNGInfo* info, const char* key, const char* str) {
		  return lodepng_add_text_sized(info, key, str, lodepng_strlen(str));
		}

		void lodepng_clear_text(LodePNGInfo* info) {
		  LodePNGText_cleanup(info);
		}

		/******************************************************************************/

		static void LodePNGIText_init(LodePNGInfo* info) {
		  info.itext_num = 0;
		  info.itext_keys = NULL;
		  info.itext_langtags = NULL;
		  info.itext_transkeys = NULL;
		  info.itext_strings = NULL;
		}

		static void LodePNGIText_cleanup(LodePNGInfo* info) {
		  size_t i;
		  for(i = 0; i != info.itext_num; ++i) {
		    string_cleanup(&info.itext_keys[i]);
		    string_cleanup(&info.itext_langtags[i]);
		    string_cleanup(&info.itext_transkeys[i]);
		    string_cleanup(&info.itext_strings[i]);
		  }
		  lodepng_free(info.itext_keys);
		  lodepng_free(info.itext_langtags);
		  lodepng_free(info.itext_transkeys);
		  lodepng_free(info.itext_strings);
		}

		static unsigned LodePNGIText_copy(LodePNGInfo* dest, const LodePNGInfo* source) {
		  size_t i = 0;
		  dest.itext_keys = NULL;
		  dest.itext_langtags = NULL;
		  dest.itext_transkeys = NULL;
		  dest.itext_strings = NULL;
		  dest.itext_num = 0;
		  for(i = 0; i != source.itext_num; ++i) {
		    CERROR_TRY_RETURN(lodepng_add_itext(dest, source.itext_keys[i], source.itext_langtags[i],
		                                        source.itext_transkeys[i], source.itext_strings[i]));
		  }
		  return 0;
		}

		void lodepng_clear_itext(LodePNGInfo* info) {
		  LodePNGIText_cleanup(info);
		}

		static unsigned lodepng_add_itext_sized(LodePNGInfo* info, const char* key, const char* langtag,
		                                        const char* transkey, const char* str, size_t size) {
		  char** new_keys = (char**)(lodepng_realloc(info.itext_keys, sizeof(char*) * (info.itext_num + 1)));
		  char** new_langtags = (char**)(lodepng_realloc(info.itext_langtags, sizeof(char*) * (info.itext_num + 1)));
		  char** new_transkeys = (char**)(lodepng_realloc(info.itext_transkeys, sizeof(char*) * (info.itext_num + 1)));
		  char** new_strings = (char**)(lodepng_realloc(info.itext_strings, sizeof(char*) * (info.itext_num + 1)));

		  if(new_keys) info.itext_keys = new_keys;
		  if(new_langtags) info.itext_langtags = new_langtags;
		  if(new_transkeys) info.itext_transkeys = new_transkeys;
		  if(new_strings) info.itext_strings = new_strings;

		  if(!new_keys || !new_langtags || !new_transkeys || !new_strings) return 83; /*alloc fail*/

		  ++info.itext_num;

		  info.itext_keys[info.itext_num - 1] = alloc_string(key);
		  info.itext_langtags[info.itext_num - 1] = alloc_string(langtag);
		  info.itext_transkeys[info.itext_num - 1] = alloc_string(transkey);
		  info.itext_strings[info.itext_num - 1] = alloc_string_sized(str, size);

		  return 0;
		}

		unsigned lodepng_add_itext(LodePNGInfo* info, const char* key, const char* langtag,
		                           const char* transkey, const char* str) {
		  return lodepng_add_itext_sized(info, key, langtag, transkey, str, lodepng_strlen(str));
		}

		/* same as set but does not delete */
		static unsigned lodepng_assign_icc(LodePNGInfo* info, const char* name, const uint8* profile, unsigned profile_size) {
		  if(profile_size == 0) return 100; /*invalid ICC profile size*/

		  info.iccp_name = alloc_string(name);
		  info.iccp_profile = (uint8*)lodepng_malloc(profile_size);

		  if(!info.iccp_name || !info.iccp_profile) return 83; /*alloc fail*/

		  lodepng_memcpy(info.iccp_profile, profile, profile_size);
		  info.iccp_profile_size = profile_size;

		  return 0; /*ok*/
		}

		unsigned lodepng_set_icc(LodePNGInfo* info, const char* name, const uint8* profile, unsigned profile_size) {
		  if(info.iccp_name) lodepng_clear_icc(info);
		  info.iccp_defined = 1;

		  return lodepng_assign_icc(info, name, profile, profile_size);
		}

		void lodepng_clear_icc(LodePNGInfo* info) {
		  string_cleanup(&info.iccp_name);
		  lodepng_free(info.iccp_profile);
		  info.iccp_profile = NULL;
		  info.iccp_profile_size = 0;
		  info.iccp_defined = 0;
		}
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/

		static void lodepng_info_init(LodePNGInfo* info) {
		  lodepng_color_mode_init(&info.color);
		  info.interlace_method = 0;
		  info.compression_method = 0;
		  info.filter_method = 0;
#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		  info.background_defined = 0;
		  info.background_r = info.background_g = info.background_b = 0;

		  LodePNGText_init(info);
		  LodePNGIText_init(info);

		  info.time_defined = 0;
		  info.phys_defined = 0;

		  info.gama_defined = 0;
		  info.chrm_defined = 0;
		  info.srgb_defined = 0;
		  info.iccp_defined = 0;
		  info.iccp_name = NULL;
		  info.iccp_profile = NULL;

		  LodePNGUnknownChunks_init(info);
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
		}

		static void lodepng_info_cleanup(LodePNGInfo* info) {
		  lodepng_color_mode_cleanup(&info.color);
#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		  LodePNGText_cleanup(info);
		  LodePNGIText_cleanup(info);

		  lodepng_clear_icc(info);

		  LodePNGUnknownChunks_cleanup(info);
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
		}

		static unsigned lodepng_info_copy(LodePNGInfo* dest, LodePNGInfo* source) {
		  lodepng_info_cleanup(dest);
		  lodepng_memcpy(dest, source, sizeof(LodePNGInfo));
		  lodepng_color_mode_init(&dest.color);
		  CERROR_TRY_RETURN!(lodepng_color_mode_copy(&dest.color, &source.color));

#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		  CERROR_TRY_RETURN(LodePNGText_copy(dest, source));
		  CERROR_TRY_RETURN(LodePNGIText_copy(dest, source));
		  if(source.iccp_defined) {
		    CERROR_TRY_RETURN(lodepng_assign_icc(dest, source.iccp_name, source.iccp_profile, source.iccp_profile_size));
		  }

		  LodePNGUnknownChunks_init(dest);
		  CERROR_TRY_RETURN(LodePNGUnknownChunks_copy(dest, source));
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
		  return 0;
		}

		/* ////////////////////////////////////////////////////////////////////////// */

		/*index: bitgroup index, bits: bitgroup size(1, 2 or 4), in: bitgroup value, out: octet array to add bits to*/
		static void addColorBits(uint8* _out, size_t index, unsigned bits, unsigned _in) {
			var _in;
		  unsigned m = bits == 1 ? 7 : bits == 2 ? 3 : 1; /*8 / bits - 1*/
		  /*p = the partial index in the byte, e.g. with 4 palettebits it is 0 for first half or 1 for second half*/
		  unsigned p = index & m;
		  _in &= (1u << bits) - 1u; /*filter out any other bits of the input value*/
		  _in = _in << (bits * (m - p));
		  if(p == 0) _out[index * bits / 8u] = (.)_in;
		  else _out[index * bits / 8u] |= (.)_in;
		}

		//struct ColorTree ColorTree;

		/*
		One node of a color tree
		This is the data structure used to count the number of unique colors and to get a palette
		index for a color. It's like an octree, but because the alpha channel is used too, each
		node has 16 instead of 8 children.
		*/
		struct ColorTree {
		  public ColorTree*[16] children; /*up to 16 pointers to ColorTree of next level*/
		  public int index; /*the payload. Only has a meaningful value if this is in the last level*/
		};

		static void color_tree_init(ColorTree* tree) {
		  lodepng_memset(&tree.children[0], 0, 16 * sizeof(ColorTree*));
		  tree.index = -1;
		}

		static void color_tree_cleanup(ColorTree* tree) {
		  int i;
		  for(i = 0; i != 16; ++i) {
		    if(tree.children[i] != null) {
		      color_tree_cleanup(tree.children[i]);
		      lodepng_free(tree.children[i]);
		    }
		  }
		}

		/*returns -1 if color not present, its index otherwise*/
		static int color_tree_get(ColorTree* tree, uint8 r, uint8 g, uint8 b, uint8 a) {
			var tree;
		  int bit = 0;
		  for(bit = 0; bit < 8; ++bit) {
		    int i = 8 * ((r >> bit) & 1) + 4 * ((g >> bit) & 1) + 2 * ((b >> bit) & 1) + 1 * ((a >> bit) & 1);
		    if(tree.children[i] == null) return -1;
		    else tree = tree.children[i];
		  }
		  return tree != null ? tree.index : -1;
		}

#if LODEPNG_COMPILE_ENCODER
		static int color_tree_has(ColorTree* tree, uint8 r, uint8 g, uint8 b, uint8 a) {
		  return color_tree_get(tree, r, g, b, a) >= 0;
		}
#endif /*LODEPNG_COMPILE_ENCODER*/

		/*color is not allowed to already exist.
		Index should be >= 0 (it's signed to be compatible with using -1 for "doesn't exist")
		Returns error code, or 0 if ok*/
		static unsigned color_tree_add(ColorTree* tree,
		                               uint8 r, uint8 g, uint8 b, uint8 a, unsigned index) {
										   var tree;
		  int bit;
		  for(bit = 0; bit < 8; ++bit) {
		    int i = 8 * ((r >> bit) & 1) + 4 * ((g >> bit) & 1) + 2 * ((b >> bit) & 1) + 1 * ((a >> bit) & 1);
		    if(tree.children[i] == null) {
		      tree.children[i] = (ColorTree*)lodepng_malloc(sizeof(ColorTree));
		      if(tree.children[i] == null) return 83; /*alloc fail*/
		      color_tree_init(tree.children[i]);
		    }
		    tree = tree.children[i];
		  }
		  tree.index = (int)index;
		  return 0;
		}

		/*put a pixel, given its RGBA color, into image of any color type*/
		static unsigned rgba8ToPixel(uint8* _out, size_t i,
		                             LodePNGColorMode* mode, ColorTree* tree /*for palette*/,
		                             uint8 r, uint8 g, uint8 b, uint8 a) {
		  if(mode.colortype == .LCT_GREY) {
		    uint8 gray = r; /*((uint16)r + g + b) / 3u;*/
		    if(mode.bitdepth == 8) _out[i] = gray;
		    else if(mode.bitdepth == 16) _out[i * 2 + 0] = _out[i * 2 + 1] = gray;
		    else {
		      /*take the most significant bits of gray*/
		      gray = (.)((unsigned)gray >> (8u - mode.bitdepth)) & ((1u << mode.bitdepth) - 1u);
		      addColorBits(_out, i, mode.bitdepth, gray);
		    }
		  } else if(mode.colortype == .LCT_RGB) {
		    if(mode.bitdepth == 8) {
		      _out[i * 3 + 0] = r;
		      _out[i * 3 + 1] = g;
		      _out[i * 3 + 2] = b;
		    } else {
		      _out[i * 6 + 0] = _out[i * 6 + 1] = r;
		      _out[i * 6 + 2] = _out[i * 6 + 3] = g;
		      _out[i * 6 + 4] = _out[i * 6 + 5] = b;
		    }
		  } else if(mode.colortype == .LCT_PALETTE) {
		    int index = color_tree_get(tree, r, g, b, a);
		    if(index < 0) return 82; /*color not in palette*/
		    if(mode.bitdepth == 8) _out[i] = (.)index;
		    else addColorBits(_out, i, mode.bitdepth, (unsigned)index);
		  } else if(mode.colortype == .LCT_GREY_ALPHA) {
		    uint8 gray = r; /*((uint16)r + g + b) / 3u;*/
		    if(mode.bitdepth == 8) {
		      _out[i * 2 + 0] = gray;
		      _out[i * 2 + 1] = a;
		    } else if(mode.bitdepth == 16) {
		      _out[i * 4 + 0] = _out[i * 4 + 1] = gray;
		      _out[i * 4 + 2] = _out[i * 4 + 3] = a;
		    }
		  } else if(mode.colortype == .LCT_RGBA) {
		    if(mode.bitdepth == 8) {
		      _out[i * 4 + 0] = r;
		      _out[i * 4 + 1] = g;
		      _out[i * 4 + 2] = b;
		      _out[i * 4 + 3] = a;
		    } else {
		      _out[i * 8 + 0] = _out[i * 8 + 1] = r;
		      _out[i * 8 + 2] = _out[i * 8 + 3] = g;
		      _out[i * 8 + 4] = _out[i * 8 + 5] = b;
		      _out[i * 8 + 6] = _out[i * 8 + 7] = a;
		    }
		  }

		  return 0; /*no error*/
		}

		/*put a pixel, given its RGBA16 color, into image of any color 16-bitdepth type*/
		static void rgba16ToPixel(uint8* _out, size_t i,
		                         LodePNGColorMode* mode,
		                         uint16 r, uint16 g, uint16 b, uint16 a) {
		  if(mode.colortype == .LCT_GREY) {
		    uint16 gray = r; /*((unsigned)r + g + b) / 3u;*/
		    _out[i * 2 + 0] = (.)((gray >> 8) & 255);
		    _out[i * 2 + 1] = (.)((gray & 255));
		  } else if(mode.colortype == .LCT_RGB) {
		    _out[i * 6 + 0] = (.)((r >> 8) & 255);
		    _out[i * 6 + 1] = (.)(r & 255);
		    _out[i * 6 + 2] = (.)((g >> 8) & 255);
		    _out[i * 6 + 3] = (.)(g & 255);
		    _out[i * 6 + 4] = (.)((b >> 8) & 255);
		    _out[i * 6 + 5] = (.)(b & 255);
		  } else if(mode.colortype == .LCT_GREY_ALPHA) {
		    uint16 gray = r; /*((unsigned)r + g + b) / 3u;*/
		    _out[i * 4 + 0] = (.)((gray >> 8) & 255);
		    _out[i * 4 + 1] = (.)(gray & 255);
		    _out[i * 4 + 2] = (.)((a >> 8) & 255);
		    _out[i * 4 + 3] = (.)(a & 255);
		  } else if(mode.colortype == .LCT_RGBA) {
		    _out[i * 8 + 0] = (.)((r >> 8) & 255);
		    _out[i * 8 + 1] = (.)(r & 255);
		    _out[i * 8 + 2] = (.)((g >> 8) & 255);
		    _out[i * 8 + 3] = (.)(g & 255);
		    _out[i * 8 + 4] = (.)((b >> 8) & 255);
		    _out[i * 8 + 5] = (.)(b & 255);
		    _out[i * 8 + 6] = (.)((a >> 8) & 255);
		    _out[i * 8 + 7] = (.)(a & 255);
		  }
		}

		/*Get RGBA8 color of pixel with index i (y * width + x) from the raw image with given color type.*/
		static void getPixelColorRGBA8(uint8* r, uint8* g,
		                               uint8* b, uint8* a,
		                               uint8* _in, size_t i,
		                               LodePNGColorMode* mode) {
		  if(mode.colortype == .LCT_GREY) {
		    if(mode.bitdepth == 8) {
		      *r = *g = *b = _in[i];
		      if(mode.key_defined && *r == mode.key_r) *a = 0;
		      else *a = 255;
		    } else if(mode.bitdepth == 16) {
		      *r = *g = *b = _in[i * 2 + 0];
		      if(mode.key_defined && 256U * _in[i * 2 + 0] + _in[i * 2 + 1] == mode.key_r) *a = 0;
		      else *a = 255;
		    } else {
		      unsigned highest = ((1U << mode.bitdepth) - 1U); /*highest possible value for this bit depth*/
		      size_t j = i * mode.bitdepth;
		      unsigned value = readBitsFromReversedStream(&j, _in, mode.bitdepth);
		      *r = *g = *b = (.)((value * 255) / highest);
		      if(mode.key_defined && value == mode.key_r) *a = 0;
		      else *a = 255;
		    }
		  } else if(mode.colortype == .LCT_RGB) {
		    if(mode.bitdepth == 8) {
		      *r = _in[i * 3 + 0]; *g = _in[i * 3 + 1]; *b = _in[i * 3 + 2];
		      if(mode.key_defined && *r == mode.key_r && *g == mode.key_g && *b == mode.key_b) *a = 0;
		      else *a = 255;
		    } else {
		      *r = _in[i * 6 + 0];
		      *g = _in[i * 6 + 2];
		      *b = _in[i * 6 + 4];
		      if(mode.key_defined && 256U * _in[i * 6 + 0] + _in[i * 6 + 1] == mode.key_r
		         && 256U * _in[i * 6 + 2] + _in[i * 6 + 3] == mode.key_g
		         && 256U * _in[i * 6 + 4] + _in[i * 6 + 5] == mode.key_b) *a = 0;
		      else *a = 255;
		    }
		  } else if(mode.colortype == .LCT_PALETTE) {
		    unsigned index;
		    if(mode.bitdepth == 8) index = _in[i];
		    else {
		      size_t j = i * mode.bitdepth;
		      index = readBitsFromReversedStream(&j, _in, mode.bitdepth);
		    }
		    /*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/
		    *r = mode.palette[index * 4 + 0];
		    *g = mode.palette[index * 4 + 1];
		    *b = mode.palette[index * 4 + 2];
		    *a = mode.palette[index * 4 + 3];
		  } else if(mode.colortype == .LCT_GREY_ALPHA) {
		    if(mode.bitdepth == 8) {
		      *r = *g = *b = _in[i * 2 + 0];
		      *a = _in[i * 2 + 1];
		    } else {
		      *r = *g = *b = _in[i * 4 + 0];
		      *a = _in[i * 4 + 2];
		    }
		  } else if(mode.colortype == .LCT_RGBA) {
		    if(mode.bitdepth == 8) {
		      *r = _in[i * 4 + 0];
		      *g = _in[i * 4 + 1];
		      *b = _in[i * 4 + 2];
		      *a = _in[i * 4 + 3];
		    } else {
		      *r = _in[i * 8 + 0];
		      *g = _in[i * 8 + 2];
		      *b = _in[i * 8 + 4];
		      *a = _in[i * 8 + 6];
		    }
		  }
		}

		/*Similar to getPixelColorRGBA8, but with all the for loops inside of the color
		mode test cases, optimized to convert the colors much faster, when converting
		to the common case of RGBA with 8 bit per channel. buffer must be RGBA with
		enough memory.*/
		static void getPixelColorsRGBA8(uint8* /*LODEPNG_RESTRICT*/ buffer, size_t numpixels,
		                                uint8* /*LODEPNG_RESTRICT*/ _in,
		                                LodePNGColorMode* mode) {
											var buffer;
		  unsigned num_channels = 4;
		  size_t i;
		  if(mode.colortype == .LCT_GREY) {
		    if(mode.bitdepth == 8) {
		      for(i = 0; i != numpixels; ++i, buffer += num_channels) {
		        buffer[0] = buffer[1] = buffer[2] = _in[i];
		        buffer[3] = 255;
		      }
		      if(mode.key_defined) {
		        buffer -= numpixels * num_channels;
		        for(i = 0; i != numpixels; ++i, buffer += num_channels) {
		          if(buffer[0] == mode.key_r) buffer[3] = 0;
		        }
		      }
		    } else if(mode.bitdepth == 16) {
		      for(i = 0; i != numpixels; ++i, buffer += num_channels) {
		        buffer[0] = buffer[1] = buffer[2] = _in[i * 2];
		        buffer[3] = mode.key_defined && 256U * _in[i * 2 + 0] + _in[i * 2 + 1] == mode.key_r ? 0 : 255;
		      }
		    } else {
		      unsigned highest = ((1U << mode.bitdepth) - 1U); /*highest possible value for this bit depth*/
		      size_t j = 0;
		      for(i = 0; i != numpixels; ++i, buffer += num_channels) {
		        unsigned value = readBitsFromReversedStream(&j, _in, mode.bitdepth);
		        buffer[0] = buffer[1] = buffer[2] = (.)((value * 255) / highest);
		        buffer[3] = mode.key_defined && value == mode.key_r ? 0 : 255;
		      }
		    }
		  } else if(mode.colortype == .LCT_RGB) {
		    if(mode.bitdepth == 8) {
		      for(i = 0; i != numpixels; ++i, buffer += num_channels) {
		        lodepng_memcpy(buffer, &_in[i * 3], 3);
		        buffer[3] = 255;
		      }
		      if(mode.key_defined) {
		        buffer -= numpixels * num_channels;
		        for(i = 0; i != numpixels; ++i, buffer += num_channels) {
		          if(buffer[0] == mode.key_r && buffer[1]== mode.key_g && buffer[2] == mode.key_b) buffer[3] = 0;
		        }
		      }
		    } else {
		      for(i = 0; i != numpixels; ++i, buffer += num_channels) {
		        buffer[0] = _in[i * 6 + 0];
		        buffer[1] = _in[i * 6 + 2];
		        buffer[2] = _in[i * 6 + 4];
		        buffer[3] = mode.key_defined
		           && 256U * _in[i * 6 + 0] + _in[i * 6 + 1] == mode.key_r
		           && 256U * _in[i * 6 + 2] + _in[i * 6 + 3] == mode.key_g
		           && 256U * _in[i * 6 + 4] + _in[i * 6 + 5] == mode.key_b ? 0 : 255;
		      }
		    }
		  } else if(mode.colortype == .LCT_PALETTE) {
		    if(mode.bitdepth == 8) {
		      for(i = 0; i != numpixels; ++i, buffer += num_channels) {
		        unsigned index = _in[i];
		        /*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/
		        lodepng_memcpy(buffer, &mode.palette[index * 4], 4);
		      }
		    } else {
		      size_t j = 0;
		      for(i = 0; i != numpixels; ++i, buffer += num_channels) {
		        unsigned index = readBitsFromReversedStream(&j, _in, mode.bitdepth);
		        /*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/
		        lodepng_memcpy(buffer, &mode.palette[index * 4], 4);
		      }
		    }
		  } else if(mode.colortype == .LCT_GREY_ALPHA) {
		    if(mode.bitdepth == 8) {
		      for(i = 0; i != numpixels; ++i, buffer += num_channels) {
		        buffer[0] = buffer[1] = buffer[2] = _in[i * 2 + 0];
		        buffer[3] = _in[i * 2 + 1];
		      }
		    } else {
		      for(i = 0; i != numpixels; ++i, buffer += num_channels) {
		        buffer[0] = buffer[1] = buffer[2] = _in[i * 4 + 0];
		        buffer[3] = _in[i * 4 + 2];
		      }
		    }
		  } else if(mode.colortype == .LCT_RGBA) {
		    if(mode.bitdepth == 8) {
		      lodepng_memcpy(buffer, _in, numpixels * 4);
		    } else {
		      for(i = 0; i != numpixels; ++i, buffer += num_channels) {
		        buffer[0] = _in[i * 8 + 0];
		        buffer[1] = _in[i * 8 + 2];
		        buffer[2] = _in[i * 8 + 4];
		        buffer[3] = _in[i * 8 + 6];
		      }
		    }
		  }
		}

		/*Similar to getPixelColorsRGBA8, but with 3-channel RGB output.*/
		static void getPixelColorsRGB8(uint8* /*LODEPNG_RESTRICT*/ buffer, size_t numpixels,
		                               uint8* /*LODEPNG_RESTRICT*/ _in,
		                               LodePNGColorMode* mode) {
										   var buffer;
		  const unsigned num_channels = 3;
		  size_t i;
		  if(mode.colortype == .LCT_GREY) {
		    if(mode.bitdepth == 8) {
		      for(i = 0; i != numpixels; ++i, buffer += num_channels) {
		        buffer[0] = buffer[1] = buffer[2] = _in[i];
		      }
		    } else if(mode.bitdepth == 16) {
		      for(i = 0; i != numpixels; ++i, buffer += num_channels) {
		        buffer[0] = buffer[1] = buffer[2] = _in[i * 2];
		      }
		    } else {
		      unsigned highest = ((1U << mode.bitdepth) - 1U); /*highest possible value for this bit depth*/
		      size_t j = 0;
		      for(i = 0; i != numpixels; ++i, buffer += num_channels) {
		        unsigned value = readBitsFromReversedStream(&j, _in, mode.bitdepth);
		        buffer[0] = buffer[1] = buffer[2] = (.)((value * 255) / highest);
		      }
		    }
		  } else if(mode.colortype == .LCT_RGB) {
		    if(mode.bitdepth == 8) {
		      lodepng_memcpy(buffer, _in, numpixels * 3);
		    } else {
		      for(i = 0; i != numpixels; ++i, buffer += num_channels) {
		        buffer[0] = _in[i * 6 + 0];
		        buffer[1] = _in[i * 6 + 2];
		        buffer[2] = _in[i * 6 + 4];
		      }
		    }
		  } else if(mode.colortype == .LCT_PALETTE) {
		    if(mode.bitdepth == 8) {
		      for(i = 0; i != numpixels; ++i, buffer += num_channels) {
		        unsigned index = _in[i];
		        /*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/
		        lodepng_memcpy(buffer, &mode.palette[index * 4], 3);
		      }
		    } else {
		      size_t j = 0;
		      for(i = 0; i != numpixels; ++i, buffer += num_channels) {
		        unsigned index = readBitsFromReversedStream(&j, _in, mode.bitdepth);
		        /*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/
		        lodepng_memcpy(buffer, &mode.palette[index * 4], 3);
		      }
		    }
		  } else if(mode.colortype == .LCT_GREY_ALPHA) {
		    if(mode.bitdepth == 8) {
		      for(i = 0; i != numpixels; ++i, buffer += num_channels) {
		        buffer[0] = buffer[1] = buffer[2] = _in[i * 2 + 0];
		      }
		    } else {
		      for(i = 0; i != numpixels; ++i, buffer += num_channels) {
		        buffer[0] = buffer[1] = buffer[2] = _in[i * 4 + 0];
		      }
		    }
		  } else if(mode.colortype == .LCT_RGBA) {
		    if(mode.bitdepth == 8) {
		      for(i = 0; i != numpixels; ++i, buffer += num_channels) {
		        lodepng_memcpy(buffer, &_in[i * 4], 3);
		      }
		    } else {
		      for(i = 0; i != numpixels; ++i, buffer += num_channels) {
		        buffer[0] = _in[i * 8 + 0];
		        buffer[1] = _in[i * 8 + 2];
		        buffer[2] = _in[i * 8 + 4];
		      }
		    }
		  }
		}

		/*Get RGBA16 color of pixel with index i (y * width + x) from the raw image with
		given color type, but the given color type must be 16-bit itself.*/
		static void getPixelColorRGBA16(uint16* r, uint16* g, uint16* b, uint16* a,
		                                uint8* _in, size_t i, LodePNGColorMode* mode) {
		  if(mode.colortype == .LCT_GREY) {
		    *r = *g = *b = 256 * _in[i * 2 + 0] + _in[i * 2 + 1];
		    if(mode.key_defined && 256U * _in[i * 2 + 0] + _in[i * 2 + 1] == mode.key_r) *a = 0;
		    else *a = 65535;
		  } else if(mode.colortype == .LCT_RGB) {
		    *r = 256u * _in[i * 6 + 0] + _in[i * 6 + 1];
		    *g = 256u * _in[i * 6 + 2] + _in[i * 6 + 3];
		    *b = 256u * _in[i * 6 + 4] + _in[i * 6 + 5];
		    if(mode.key_defined
		       && 256u * _in[i * 6 + 0] + _in[i * 6 + 1] == mode.key_r
		       && 256u * _in[i * 6 + 2] + _in[i * 6 + 3] == mode.key_g
		       && 256u * _in[i * 6 + 4] + _in[i * 6 + 5] == mode.key_b) *a = 0;
		    else *a = 65535;
		  } else if(mode.colortype == .LCT_GREY_ALPHA) {
		    *r = *g = *b = 256u * _in[i * 4 + 0] + _in[i * 4 + 1];
		    *a = 256u * _in[i * 4 + 2] + _in[i * 4 + 3];
		  } else if(mode.colortype == .LCT_RGBA) {
		    *r = 256u * _in[i * 8 + 0] + _in[i * 8 + 1];
		    *g = 256u * _in[i * 8 + 2] + _in[i * 8 + 3];
		    *b = 256u * _in[i * 8 + 4] + _in[i * 8 + 5];
		    *a = 256u * _in[i * 8 + 6] + _in[i * 8 + 7];
		  }
		}

		static unsigned lodepng_convert(uint8* _out, uint8* _in,
		                         LodePNGColorMode* mode_out, LodePNGColorMode* mode_in,
		                         unsigned w, unsigned h) {
		  size_t i;
		  ColorTree tree;
		  size_t numpixels = (size_t)w * (size_t)h;
		  unsigned error = 0;

		  if(mode_in.colortype == .LCT_PALETTE && mode_in.palette == null) {
		    return 107; /* error: must provide palette if input mode is palette */
		  }

		  if(lodepng_color_mode_equal(mode_out, mode_in)) {
		    size_t numbytes = lodepng_get_raw_size(w, h, mode_in);
		    lodepng_memcpy(_out, _in, numbytes);
		    return 0;
		  }

		  if(mode_out.colortype == .LCT_PALETTE) {
		    size_t palettesize = mode_out.palettesize;
		    uint8* palette = mode_out.palette;
		    size_t palsize = (size_t)1u << mode_out.bitdepth;
		    /*if the user specified output palette but did not give the values, assume
		    they want the values of the input color type (assuming that one is palette).
		    Note that we never create a new palette ourselves.*/
		    if(palettesize == 0) {
		      palettesize = mode_in.palettesize;
		      palette = mode_in.palette;
		      /*if the input was also palette with same bitdepth, then the color types are also
		      equal, so copy literally. This to preserve the exact indices that were in the PNG
		      even in case there are duplicate colors in the palette.*/
		      if(mode_in.colortype == .LCT_PALETTE && mode_in.bitdepth == mode_out.bitdepth) {
		        size_t numbytes = lodepng_get_raw_size(w, h, mode_in);
		        lodepng_memcpy(_out, _in, numbytes);
		        return 0;
		      }
		    }
		    if(palettesize < palsize) palsize = palettesize;
		    color_tree_init(&tree);
		    for(i = 0; i != palsize; ++i) {
		      uint8* p = &palette[i * 4];
		      error = color_tree_add(&tree, p[0], p[1], p[2], p[3], (unsigned)i);
		      if(error != 0) break;
		    }
		  }

		  if(error != 0) {
		    if(mode_in.bitdepth == 16 && mode_out.bitdepth == 16) {
		      for(i = 0; i != numpixels; ++i) {
		        uint16 r = 0, g = 0, b = 0, a = 0;
		        getPixelColorRGBA16(&r, &g, &b, &a, _in, i, mode_in);
		        rgba16ToPixel(_out, i, mode_out, r, g, b, a);
		      }
		    } else if(mode_out.bitdepth == 8 && mode_out.colortype == .LCT_RGBA) {
		      getPixelColorsRGBA8(_out, numpixels, _in, mode_in);
		    } else if(mode_out.bitdepth == 8 && mode_out.colortype == .LCT_RGB) {
		      getPixelColorsRGB8(_out, numpixels, _in, mode_in);
		    } else {
		      uint8 r = 0, g = 0, b = 0, a = 0;
		      for(i = 0; i != numpixels; ++i) {
		        getPixelColorRGBA8(&r, &g, &b, &a, _in, i, mode_in);
		        error = rgba8ToPixel(_out, i, mode_out, &tree, r, g, b, a);
		        if(error != 0) break;
		      }
		    }
		  }

		  if(mode_out.colortype == .LCT_PALETTE) {
		    color_tree_cleanup(&tree);
		  }

		  return error;
		}


		/* Converts a single rgb color without alpha from one type to another, color bits truncated to
		their bitdepth. In case of single channel (gray or palette), only the r channel is used. Slow
		function, do not use to process all pixels of an image. Alpha channel not supported on purpose:
		this is for bKGD, supporting alpha may prevent it from finding a color in the palette, from the
		specification it looks like bKGD should ignore the alpha values of the palette since it can use
		any palette index but doesn't have an alpha channel. Idem with ignoring color key. */
		unsigned lodepng_convert_rgb(
		    unsigned* r_out, unsigned* g_out, unsigned* b_out,
		    unsigned r_in, unsigned g_in, unsigned b_in,
		    LodePNGColorMode* mode_out, LodePNGColorMode* mode_in) {
		  unsigned r = 0, g = 0, b = 0;
		  unsigned mul = 65535 / ((1u << mode_in.bitdepth) - 1u); /*65535, 21845, 4369, 257, 1*/
		  unsigned shift = 16 - mode_out.bitdepth;

		  if(mode_in.colortype == .LCT_GREY || mode_in.colortype == .LCT_GREY_ALPHA) {
		    r = g = b = r_in * mul;
		  } else if(mode_in.colortype == .LCT_RGB || mode_in.colortype == .LCT_RGBA) {
		    r = r_in * mul;
		    g = g_in * mul;
		    b = b_in * mul;
		  } else if(mode_in.colortype == .LCT_PALETTE) {
		    if(r_in >= mode_in.palettesize) return 82;
		    r = (.)mode_in.palette[r_in * 4 + 0] * 257u;
		    g = (.)mode_in.palette[r_in * 4 + 1] * 257u;
		    b = (.)mode_in.palette[r_in * 4 + 2] * 257u;
		  } else {
		    return 31;
		  }

		  /* now convert to output format */
		  if(mode_out.colortype == .LCT_GREY || mode_out.colortype == .LCT_GREY_ALPHA) {
		    *r_out = r >> shift ;
		  } else if(mode_out.colortype == .LCT_RGB || mode_out.colortype == .LCT_RGBA) {
		    *r_out = r >> shift ;
		    *g_out = g >> shift ;
		    *b_out = b >> shift ;
		  } else if(mode_out.colortype == .LCT_PALETTE) {
		    unsigned i;
		    /* a 16-bit color cannot be in the palette */
		    if((r >> 8) != (r & 255) || (g >> 8) != (g & 255) || (b >> 8) != (b & 255)) return 82;
		    for(i = 0; i < mode_out.palettesize; i++) {
		      unsigned j = i * 4;
		      if((r >> 8) == mode_out.palette[j + 0] && (g >> 8) == mode_out.palette[j + 1] &&
		          (b >> 8) == mode_out.palette[j + 2]) {
		        *r_out = i;
		        return 0;
		      }
		    }
		    return 82;
		  } else {
		    return 31;
		  }

		  return 0;
		}

#if LODEPNG_COMPILE_ENCODER

		void lodepng_color_stats_init(LodePNGColorStats* stats) {
		  /*stats*/
		  stats.colored = 0;
		  stats.key = 0;
		  stats.key_r = stats.key_g = stats.key_b = 0;
		  stats.alpha = 0;
		  stats.numcolors = 0;
		  stats.bits = 1;
		  stats.numpixels = 0;
		  /*settings*/
		  stats.allow_palette = 1;
		  stats.allow_greyscale = 1;
		}

		/*function used for debug purposes with C++*/
		/*void printColorStats(LodePNGColorStats* p) {
		  std::cout << "colored: " << (int)p.colored << ", ";
		  std::cout << "key: " << (int)p.key << ", ";
		  std::cout << "key_r: " << (int)p.key_r << ", ";
		  std::cout << "key_g: " << (int)p.key_g << ", ";
		  std::cout << "key_b: " << (int)p.key_b << ", ";
		  std::cout << "alpha: " << (int)p.alpha << ", ";
		  std::cout << "numcolors: " << (int)p.numcolors << ", ";
		  std::cout << "bits: " << (int)p.bits << std::endl;
		}*/

		/*Returns how many bits needed to represent given value (max 8 bit)*/
		static unsigned getValueRequiredBits(uint8 value) {
		  if(value == 0 || value == 255) return 1;
		  /*The scaling of 2-bit and 4-bit values uses multiples of 85 and 17*/
		  if(value % 17 == 0) return value % 85 == 0 ? 2 : 4;
		  return 8;
		}

		/*stats must already have been inited. */
		unsigned lodepng_compute_color_stats(LodePNGColorStats* stats,
		                                     const uint8* in, unsigned w, unsigned h,
		                                     const LodePNGColorMode* mode_in) {
		  size_t i;
		  ColorTree tree;
		  size_t numpixels = (size_t)w * (size_t)h;
		  unsigned error = 0;

		  /* mark things as done already if it would be impossible to have a more expensive case */
		  unsigned colored_done = lodepng_is_greyscale_type(mode_in) ? 1 : 0;
		  unsigned alpha_done = lodepng_can_have_alpha(mode_in) ? 0 : 1;
		  unsigned numcolors_done = 0;
		  unsigned bpp = lodepng_get_bpp(mode_in);
		  unsigned bits_done = (stats.bits == 1 && bpp == 1) ? 1 : 0;
		  unsigned sixteen = 0; /* whether the input image is 16 bit */
		  unsigned maxnumcolors = 257;
		  if(bpp <= 8) maxnumcolors = LODEPNG_MIN(257, stats.numcolors + (1u << bpp));

		  stats.numpixels += numpixels;

		  /*if palette not allowed, no need to compute numcolors*/
		  if(!stats.allow_palette) numcolors_done = 1;

		  color_tree_init(&tree);

		  /*If the stats was already filled in from previous data, fill its palette in tree
		  and mark things as done already if we know they are the most expensive case already*/
		  if(stats.alpha) alpha_done = 1;
		  if(stats.colored) colored_done = 1;
		  if(stats.bits == 16) numcolors_done = 1;
		  if(stats.bits >= bpp) bits_done = 1;
		  if(stats.numcolors >= maxnumcolors) numcolors_done = 1;

		  if(!numcolors_done) {
		    for(i = 0; i < stats.numcolors; i++) {
		      const uint8* color = &stats.palette[i * 4];
		      error = color_tree_add(&tree, color[0], color[1], color[2], color[3], i);
		      if(error) goto cleanup;
		    }
		  }

		  /*Check if the 16-bit input is truly 16-bit*/
		  if(mode_in.bitdepth == 16 && !sixteen) {
		    uint16 r = 0, g = 0, b = 0, a = 0;
		    for(i = 0; i != numpixels; ++i) {
		      getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in);
		      if((r & 255) != ((r >> 8) & 255) || (g & 255) != ((g >> 8) & 255) ||
		         (b & 255) != ((b >> 8) & 255) || (a & 255) != ((a >> 8) & 255)) /*first and second byte differ*/ {
		        stats.bits = 16;
		        sixteen = 1;
		        bits_done = 1;
		        numcolors_done = 1; /*counting colors no longer useful, palette doesn't support 16-bit*/
		        break;
		      }
		    }
		  }

		  if(sixteen) {
		    uint16 r = 0, g = 0, b = 0, a = 0;

		    for(i = 0; i != numpixels; ++i) {
		      getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in);

		      if(!colored_done && (r != g || r != b)) {
		        stats.colored = 1;
		        colored_done = 1;
		      }

		      if(!alpha_done) {
		        unsigned matchkey = (r == stats.key_r && g == stats.key_g && b == stats.key_b);
		        if(a != 65535 && (a != 0 || (stats.key && !matchkey))) {
		          stats.alpha = 1;
		          stats.key = 0;
		          alpha_done = 1;
		        } else if(a == 0 && !stats.alpha && !stats.key) {
		          stats.key = 1;
		          stats.key_r = r;
		          stats.key_g = g;
		          stats.key_b = b;
		        } else if(a == 65535 && stats.key && matchkey) {
		          /* Color key cannot be used if an opaque pixel also has that RGB color. */
		          stats.alpha = 1;
		          stats.key = 0;
		          alpha_done = 1;
		        }
		      }
		      if(alpha_done && numcolors_done && colored_done && bits_done) break;
		    }

		    if(stats.key && !stats.alpha) {
		      for(i = 0; i != numpixels; ++i) {
		        getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in);
		        if(a != 0 && r == stats.key_r && g == stats.key_g && b == stats.key_b) {
		          /* Color key cannot be used if an opaque pixel also has that RGB color. */
		          stats.alpha = 1;
		          stats.key = 0;
		          alpha_done = 1;
		        }
		      }
		    }
		  } else /* < 16-bit */ {
		    uint8 r = 0, g = 0, b = 0, a = 0;
		    for(i = 0; i != numpixels; ++i) {
		      getPixelColorRGBA8(&r, &g, &b, &a, in, i, mode_in);

		      if(!bits_done && stats.bits < 8) {
		        /*only r is checked, < 8 bits is only relevant for grayscale*/
		        unsigned bits = getValueRequiredBits(r);
		        if(bits > stats.bits) stats.bits = bits;
		      }
		      bits_done = (stats.bits >= bpp);

		      if(!colored_done && (r != g || r != b)) {
		        stats.colored = 1;
		        colored_done = 1;
		        if(stats.bits < 8) stats.bits = 8; /*PNG has no colored modes with less than 8-bit per channel*/
		      }

		      if(!alpha_done) {
		        unsigned matchkey = (r == stats.key_r && g == stats.key_g && b == stats.key_b);
		        if(a != 255 && (a != 0 || (stats.key && !matchkey))) {
		          stats.alpha = 1;
		          stats.key = 0;
		          alpha_done = 1;
		          if(stats.bits < 8) stats.bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/
		        } else if(a == 0 && !stats.alpha && !stats.key) {
		          stats.key = 1;
		          stats.key_r = r;
		          stats.key_g = g;
		          stats.key_b = b;
		        } else if(a == 255 && stats.key && matchkey) {
		          /* Color key cannot be used if an opaque pixel also has that RGB color. */
		          stats.alpha = 1;
		          stats.key = 0;
		          alpha_done = 1;
		          if(stats.bits < 8) stats.bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/
		        }
		      }

		      if(!numcolors_done) {
		        if(!color_tree_has(&tree, r, g, b, a)) {
		          error = color_tree_add(&tree, r, g, b, a, stats.numcolors);
		          if(error) goto cleanup;
		          if(stats.numcolors < 256) {
		            uint8* p = stats.palette;
		            unsigned n = stats.numcolors;
		            p[n * 4 + 0] = r;
		            p[n * 4 + 1] = g;
		            p[n * 4 + 2] = b;
		            p[n * 4 + 3] = a;
		          }
		          ++stats.numcolors;
		          numcolors_done = stats.numcolors >= maxnumcolors;
		        }
		      }

		      if(alpha_done && numcolors_done && colored_done && bits_done) break;
		    }

		    if(stats.key && !stats.alpha) {
		      for(i = 0; i != numpixels; ++i) {
		        getPixelColorRGBA8(&r, &g, &b, &a, in, i, mode_in);
		        if(a != 0 && r == stats.key_r && g == stats.key_g && b == stats.key_b) {
		          /* Color key cannot be used if an opaque pixel also has that RGB color. */
		          stats.alpha = 1;
		          stats.key = 0;
		          alpha_done = 1;
		          if(stats.bits < 8) stats.bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/
		        }
		      }
		    }

		    /*make the stats's key always 16-bit for consistency - repeat each byte twice*/
		    stats.key_r += (stats.key_r << 8);
		    stats.key_g += (stats.key_g << 8);
		    stats.key_b += (stats.key_b << 8);
		  }

		cleanup:
		  color_tree_cleanup(&tree);
		  return error;
		}

#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		/*Adds a single color to the color stats. The stats must already have been inited. The color must be given as 16-bit
		(with 2 bytes repeating for 8-bit and 65535 for opaque alpha channel). This function is expensive, do not call it for
		all pixels of an image but only for a few additional values. */
		static unsigned lodepng_color_stats_add(LodePNGColorStats* stats,
		                                        unsigned r, unsigned g, unsigned b, unsigned a) {
		  unsigned error = 0;
		  uint8 image[8];
		  LodePNGColorMode mode;
		  lodepng_color_mode_init(&mode);
		  image[0] = r >> 8; image[1] = r; image[2] = g >> 8; image[3] = g;
		  image[4] = b >> 8; image[5] = b; image[6] = a >> 8; image[7] = a;
		  mode.bitdepth = 16;
		  mode.colortype = LCT_RGBA;
		  error = lodepng_compute_color_stats(stats, image, 1, 1, &mode);
		  lodepng_color_mode_cleanup(&mode);
		  return error;
		}
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/

		/*Computes a minimal PNG color model that can contain all colors as indicated by the stats.
		The stats should be computed with lodepng_compute_color_stats.
		mode_in is raw color profile of the image the stats were computed on, to copy palette order from when relevant.
		Minimal PNG color model means the color type and bit depth that gives smallest amount of bits in the output image,
		e.g. gray if only grayscale pixels, palette if less than 256 colors, color key if only single transparent color, ...
		This is used if auto_convert is enabled (it is by default).
		*/
		static unsigned auto_choose_color(LodePNGColorMode* mode_out,
		                                  const LodePNGColorMode* mode_in,
		                                  const LodePNGColorStats* stats) {
		  unsigned error = 0;
		  unsigned palettebits;
		  size_t i, n;
		  size_t numpixels = stats.numpixels;
		  unsigned palette_ok, gray_ok;

		  unsigned alpha = stats.alpha;
		  unsigned key = stats.key;
		  unsigned bits = stats.bits;

		  mode_out.key_defined = 0;

		  if(key && numpixels <= 16) {
		    alpha = 1; /*too few pixels to justify tRNS chunk overhead*/
		    key = 0;
		    if(bits < 8) bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/
		  }

		  gray_ok = !stats.colored;
		  if(!stats.allow_greyscale) gray_ok = 0;
		  if(!gray_ok && bits < 8) bits = 8;

		  n = stats.numcolors;
		  palettebits = n <= 2 ? 1 : (n <= 4 ? 2 : (n <= 16 ? 4 : 8));
		  palette_ok = n <= 256 && bits <= 8 && n != 0; /*n==0 means likely numcolors wasn't computed*/
		  if(numpixels < n * 2) palette_ok = 0; /*don't add palette overhead if image has only a few pixels*/
		  if(gray_ok && !alpha && bits <= palettebits) palette_ok = 0; /*gray is less overhead*/
		  if(!stats.allow_palette) palette_ok = 0;

		  if(palette_ok) {
		    const uint8* p = stats.palette;
		    lodepng_palette_clear(mode_out); /*remove potential earlier palette*/
		    for(i = 0; i != stats.numcolors; ++i) {
		      error = lodepng_palette_add(mode_out, p[i * 4 + 0], p[i * 4 + 1], p[i * 4 + 2], p[i * 4 + 3]);
		      if(error) break;
		    }

		    mode_out.colortype = LCT_PALETTE;
		    mode_out.bitdepth = palettebits;

		    if(mode_in.colortype == LCT_PALETTE && mode_in.palettesize >= mode_out.palettesize
		        && mode_in.bitdepth == mode_out.bitdepth) {
		      /*If input should have same palette colors, keep original to preserve its order and prevent conversion*/
		      lodepng_color_mode_cleanup(mode_out);
		      lodepng_color_mode_copy(mode_out, mode_in);
		    }
		  } else /*8-bit or 16-bit per channel*/ {
		    mode_out.bitdepth = bits;
		    mode_out.colortype = alpha ? (gray_ok ? LCT_GREY_ALPHA : LCT_RGBA)
		                                : (gray_ok ? LCT_GREY : LCT_RGB);
		    if(key) {
		      unsigned mask = (1u << mode_out.bitdepth) - 1u; /*stats always uses 16-bit, mask converts it*/
		      mode_out.key_r = stats.key_r & mask;
		      mode_out.key_g = stats.key_g & mask;
		      mode_out.key_b = stats.key_b & mask;
		      mode_out.key_defined = 1;
		    }
		  }

		  return error;
		}

#endif /* #if LODEPNG_COMPILE_ENCODER */

		/*
		Paeth predictor, used by PNG filter type 4
		The parameters are of type short, but should come from uint8s, the shorts
		are only needed to make the paeth calculation correct.
		*/
		static uint8 paethPredictor(short a, short b, short c) {
			var a;
		  short pa = LODEPNG_ABS(b - c);
		  short pb = LODEPNG_ABS(a - c);
		  short pc = LODEPNG_ABS(a + b - c - c);
		  /* return input value associated with smallest of pa, pb, pc (with certain priority if equal) */
		  if(pb < pa) { a = b; pa = pb; }
		  return (.)((pc < pa) ? c : a);
		}

		/*shared values used by multiple Adam7 related functions*/

		const unsigned[7] ADAM7_IX = .( 0, 4, 0, 2, 0, 1, 0 ); /*x start values*/
		const unsigned[7] ADAM7_IY = .( 0, 0, 4, 0, 2, 0, 1 ); /*y start values*/
		const unsigned[7] ADAM7_DX = .( 8, 8, 4, 4, 2, 2, 1 ); /*x delta values*/
		const unsigned[7] ADAM7_DY = .( 8, 8, 8, 4, 4, 2, 2 ); /*y delta values*/

		/*
		Outputs various dimensions and positions in the image related to the Adam7 reduced images.
		passw: output containing the width of the 7 passes
		passh: output containing the height of the 7 passes
		filter_passstart: output containing the index of the start and end of each
		 reduced image with filter bytes
		padded_passstart output containing the index of the start and end of each
		 reduced image when without filter bytes but with padded scanlines
		passstart: output containing the index of the start and end of each reduced
		 image without padding between scanlines, but still padding between the images
		w, h: width and height of non-interlaced image
		bpp: bits per pixel
		"padded" is only relevant if bpp is less than 8 and a scanline or image does not
		 end at a full byte
		*/
		static void Adam7_getpassvalues(ref unsigned[7] passw, ref unsigned[7] passh, ref size_t[8] filter_passstart,
		                                ref size_t[8] padded_passstart, ref size_t[8] passstart, unsigned w, unsigned h, unsigned bpp) {
		  /*the passstart values have 8 values: the 8th one indicates the byte after the end of the 7th (= last) pass*/
		  unsigned i;

		  /*calculate width and height in pixels of each pass*/
		  for(i = 0; i != 7; ++i) {
		    passw[i] = (w + ADAM7_DX[i] - ADAM7_IX[i] - 1) / ADAM7_DX[i];
		    passh[i] = (h + ADAM7_DY[i] - ADAM7_IY[i] - 1) / ADAM7_DY[i];
		    if(passw[i] == 0) passh[i] = 0;
		    if(passh[i] == 0) passw[i] = 0;
		  }

		  filter_passstart[0] = padded_passstart[0] = passstart[0] = 0;
		  for(i = 0; i != 7; ++i) {
		    /*if passw[i] is 0, it's 0 bytes, not 1 (no filtertype-byte)*/
		    filter_passstart[i + 1] = filter_passstart[i]
		                            + ((passw[i] != 0 && passh[i] != 0) ? passh[i] * (1u + (passw[i] * bpp + 7u) / 8u) : 0);
		    /*bits padded if needed to fill full byte at end of each scanline*/
		    padded_passstart[i + 1] = padded_passstart[i] + passh[i] * ((passw[i] * bpp + 7u) / 8u);
		    /*only padded at end of reduced image*/
		    passstart[i + 1] = passstart[i] + (passh[i] * passw[i] * bpp + 7u) / 8u;
		  }
		}

#if LODEPNG_COMPILE_DECODER

		/* ////////////////////////////////////////////////////////////////////////// */
		/* / PNG Decoder                                                            / */
		/* ////////////////////////////////////////////////////////////////////////// */

		/*read the information from the header and store it in the LodePNGInfo. return value is error*/
		static unsigned lodepng_inspect(unsigned* w, unsigned* h, LodePNGState* state,
		                         uint8* _in, size_t insize) {
		  unsigned width, height;
		  LodePNGInfo* info = &state.info_png;
		  if(insize == 0 || _in == null) {
		    CERROR_RETURN_ERROR!(state.error, 48); /*error: the given data is empty*/
		  }
		  if(insize < 33) {
		    CERROR_RETURN_ERROR!(state.error, 27); /*error: the data length is smaller than the length of a PNG header*/
		  }

		  /*when decoding a new PNG image, make sure all parameters created after previous decoding are reset*/
		  /* TODO: remove this. One should use a new LodePNGState for new sessions */
		  lodepng_info_cleanup(info);
		  lodepng_info_init(info);

		  if(_in[0] != 137 || _in[1] != 80 || _in[2] != 78 || _in[3] != 71
		     || _in[4] != 13 || _in[5] != 10 || _in[6] != 26 || _in[7] != 10) {
		    CERROR_RETURN_ERROR!(state.error, 28); /*error: the first 8 bytes are not the correct PNG signature*/
		  }
		  if(lodepng_chunk_length(_in + 8) != 13) {
		    CERROR_RETURN_ERROR!(state.error, 94); /*error: header size must be 13 bytes*/
		  }
		  if(!lodepng_chunk_type_equals(_in + 8, "IHDR")) {
		    CERROR_RETURN_ERROR!(state.error, 29); /*error: it doesn't start with a IHDR chunk!*/
		  }

		  /*read the values given in the header*/
		  width = lodepng_read32bitInt(&_in[16]);
		  height = lodepng_read32bitInt(&_in[20]);
		  /*TODO: remove the undocumented feature that allows to give null pointers to width or height*/
		  if(w != null) *w = width;
		  if(h != null) *h = height;
		  info.color.bitdepth = _in[24];
		  info.color.colortype = (LodePNGColorType)_in[25];
		  info.compression_method = _in[26];
		  info.filter_method = _in[27];
		  info.interlace_method = _in[28];

		  /*errors returned only after the parsing so other values are still output*/

		  /*error: invalid image size*/
		  if(width == 0 || height == 0) CERROR_RETURN_ERROR!(state.error, 93);
		  /*error: invalid colortype or bitdepth combination*/
		  state.error = checkColorValidity(info.color.colortype, info.color.bitdepth);
		  if(state.error != 0) return state.error;
		  /*error: only compression method 0 is allowed in the specification*/
		  if(info.compression_method != 0) CERROR_RETURN_ERROR!(state.error, 32);
		  /*error: only filter method 0 is allowed in the specification*/
		  if(info.filter_method != 0) CERROR_RETURN_ERROR!(state.error, 33);
		  /*error: only interlace methods 0 and 1 exist in the specification*/
		  if(info.interlace_method > 1) CERROR_RETURN_ERROR!(state.error, 34);

		  if(state.decoder.ignore_crc == 0) {
		    unsigned CRC = lodepng_read32bitInt(&_in[29]);
		    unsigned checksum = lodepng_crc32(&_in[12], 17);
		    if(CRC != checksum) {
		      CERROR_RETURN_ERROR!(state.error, 57); /*invalid CRC*/
		    }
		  }

		  return state.error;
		}

		static unsigned unfilterScanline(uint8* recon, uint8* scanline, uint8* precon,
		                                 size_t bytewidth, uint8 filterType, size_t length) {
		  /*
		  For PNG filter method 0
		  unfilter a PNG image scanline by scanline. when the pixels are smaller than 1 byte,
		  the filter works byte per byte (bytewidth = 1)
		  precon is the previous unfiltered scanline, recon the result, scanline the current one
		  the incoming scanlines do NOT include the filtertype byte, that one is given in the parameter filterType instead
		  recon and scanline MAY be the same memory address! precon must be disjoint.
		  */

		  size_t i;
		  switch(filterType) {
		    case 0:
		      for(i = 0; i != length; ++i) recon[i] = scanline[i];
		      break;
		    case 1: {
		      size_t j = 0;
		      for(i = 0; i != bytewidth; ++i) recon[i] = scanline[i];
		      for(i = bytewidth; i != length; ++i, ++j) recon[i] = scanline[i] + recon[j];
		      break;
		    }
		    case 2:
		      if(precon != null) {
		        for(i = 0; i != length; ++i) recon[i] = scanline[i] + precon[i];
		      } else {
		        for(i = 0; i != length; ++i) recon[i] = scanline[i];
		      }
		      break;
		    case 3:
		      if(precon != null) {
		        size_t j = 0;
		        for(i = 0; i != bytewidth; ++i) recon[i] = scanline[i] + (precon[i] >> 1u);
		        /* Unroll independent paths of this predictor. A 6x and 8x version is also possible but that adds
		        too much code. Whether this speeds up anything depends on compiler and settings. */
		        if(bytewidth >= 4) {
		          for(; i + 3 < length; i += 4, j += 4) {
		            uint8 s0 = scanline[i + 0], r0 = recon[j + 0], p0 = precon[i + 0];
		            uint8 s1 = scanline[i + 1], r1 = recon[j + 1], p1 = precon[i + 1];
		            uint8 s2 = scanline[i + 2], r2 = recon[j + 2], p2 = precon[i + 2];
		            uint8 s3 = scanline[i + 3], r3 = recon[j + 3], p3 = precon[i + 3];
		            recon[i + 0] = s0 + ((r0 + p0) >> 1u);
		            recon[i + 1] = s1 + ((r1 + p1) >> 1u);
		            recon[i + 2] = s2 + ((r2 + p2) >> 1u);
		            recon[i + 3] = s3 + ((r3 + p3) >> 1u);
		          }
		        } else if(bytewidth >= 3) {
		          for(; i + 2 < length; i += 3, j += 3) {
		            uint8 s0 = scanline[i + 0], r0 = recon[j + 0], p0 = precon[i + 0];
		            uint8 s1 = scanline[i + 1], r1 = recon[j + 1], p1 = precon[i + 1];
		            uint8 s2 = scanline[i + 2], r2 = recon[j + 2], p2 = precon[i + 2];
		            recon[i + 0] = s0 + ((r0 + p0) >> 1u);
		            recon[i + 1] = s1 + ((r1 + p1) >> 1u);
		            recon[i + 2] = s2 + ((r2 + p2) >> 1u);
		          }
		        } else if(bytewidth >= 2) {
		          for(; i + 1 < length; i += 2, j += 2) {
		            uint8 s0 = scanline[i + 0], r0 = recon[j + 0], p0 = precon[i + 0];
		            uint8 s1 = scanline[i + 1], r1 = recon[j + 1], p1 = precon[i + 1];
		            recon[i + 0] = s0 + ((r0 + p0) >> 1u);
		            recon[i + 1] = s1 + ((r1 + p1) >> 1u);
		          }
		        }
		        for(; i != length; ++i, ++j) recon[i] = scanline[i] + ((recon[j] + precon[i]) >> 1u);
		      } else {
		        size_t j = 0;
		        for(i = 0; i != bytewidth; ++i) recon[i] = scanline[i];
		        for(i = bytewidth; i != length; ++i, ++j) recon[i] = scanline[i] + (recon[j] >> 1u);
		      }
		      break;
		    case 4:
		      if(precon != null) {
		        size_t j = 0;
		        for(i = 0; i != bytewidth; ++i) {
		          recon[i] = (scanline[i] + precon[i]); /*paethPredictor(0, precon[i], 0) is always precon[i]*/
		        }

		        /* Unroll independent paths of the paeth predictor. A 6x and 8x version is also possible but that
		        adds too much code. Whether this speeds up anything depends on compiler and settings. */
		        if(bytewidth >= 4) {
		          for(; i + 3 < length; i += 4, j += 4) {
		            uint8 s0 = scanline[i + 0], s1 = scanline[i + 1], s2 = scanline[i + 2], s3 = scanline[i + 3];
		            uint8 r0 = recon[j + 0], r1 = recon[j + 1], r2 = recon[j + 2], r3 = recon[j + 3];
		            uint8 p0 = precon[i + 0], p1 = precon[i + 1], p2 = precon[i + 2], p3 = precon[i + 3];
		            uint8 q0 = precon[j + 0], q1 = precon[j + 1], q2 = precon[j + 2], q3 = precon[j + 3];
		            recon[i + 0] = s0 + paethPredictor(r0, p0, q0);
		            recon[i + 1] = s1 + paethPredictor(r1, p1, q1);
		            recon[i + 2] = s2 + paethPredictor(r2, p2, q2);
		            recon[i + 3] = s3 + paethPredictor(r3, p3, q3);
		          }
		        } else if(bytewidth >= 3) {
		          for(; i + 2 < length; i += 3, j += 3) {
		            uint8 s0 = scanline[i + 0], s1 = scanline[i + 1], s2 = scanline[i + 2];
		            uint8 r0 = recon[j + 0], r1 = recon[j + 1], r2 = recon[j + 2];
		            uint8 p0 = precon[i + 0], p1 = precon[i + 1], p2 = precon[i + 2];
		            uint8 q0 = precon[j + 0], q1 = precon[j + 1], q2 = precon[j + 2];
		            recon[i + 0] = s0 + paethPredictor(r0, p0, q0);
		            recon[i + 1] = s1 + paethPredictor(r1, p1, q1);
		            recon[i + 2] = s2 + paethPredictor(r2, p2, q2);
		          }
		        } else if(bytewidth >= 2) {
		          for(; i + 1 < length; i += 2, j += 2) {
		            uint8 s0 = scanline[i + 0], s1 = scanline[i + 1];
		            uint8 r0 = recon[j + 0], r1 = recon[j + 1];
		            uint8 p0 = precon[i + 0], p1 = precon[i + 1];
		            uint8 q0 = precon[j + 0], q1 = precon[j + 1];
		            recon[i + 0] = s0 + paethPredictor(r0, p0, q0);
		            recon[i + 1] = s1 + paethPredictor(r1, p1, q1);
		          }
		        }

		        for(; i != length; ++i, ++j) {
		          recon[i] = (scanline[i] + paethPredictor(recon[i - bytewidth], precon[i], precon[j]));
		        }
		      } else {
		        size_t j = 0;
		        for(i = 0; i != bytewidth; ++i) {
		          recon[i] = scanline[i];
		        }
		        for(i = bytewidth; i != length; ++i, ++j) {
		          /*paethPredictor(recon[i - bytewidth], 0, 0) is always recon[i - bytewidth]*/
		          recon[i] = (scanline[i] + recon[j]);
		        }
		      }
		      break;
		    default: return 36; /*error: invalid filter type given*/
		  }
		  return 0;
		}

		static unsigned unfilter(uint8* _out, uint8* _in, unsigned w, unsigned h, unsigned bpp) {
		  /*
		  For PNG filter method 0
		  this function unfilters a single image (e.g. without interlacing this is called once, with Adam7 seven times)
		  out must have enough bytes allocated already, in must have the scanlines + 1 filtertype byte per scanline
		  w and h are image dimensions or dimensions of reduced image, bpp is bits per pixel
		  in and out are allowed to be the same memory address (but aren't the same size since in has the extra filter bytes)
		  */

		  unsigned y;
		  uint8* prevline = null;

		  /*bytewidth is used for filtering, is 1 when bpp < 8, number of bytes per pixel otherwise*/
		  size_t bytewidth = (bpp + 7u) / 8u;
		  /*the width of a scanline in bytes, not including the filter type*/
		  size_t linebytes = lodepng_get_raw_size_idat(w, 1, bpp) - 1u;

		  for(y = 0; y < h; ++y) {
		    size_t outindex = linebytes * y;
		    size_t inindex = (1 + linebytes) * y; /*the extra filterbyte added to each row*/
		    uint8 filterType = _in[inindex];

		    CERROR_TRY_RETURN!(unfilterScanline(&_out[outindex], &_in[inindex + 1], prevline, bytewidth, filterType, linebytes));

		    prevline = &_out[outindex];
		  }

		  return 0;
		}

		/*
		in: Adam7 interlaced image, with no padding bits between scanlines, but between
		 reduced images so that each reduced image starts at a byte.
		out: the same pixels, but re-ordered so that they're now a non-interlaced image with size w*h
		bpp: bits per pixel
		out has the following size in bits: w * h * bpp.
		in is possibly bigger due to padding bits between reduced images.
		out must be big enough AND must be 0 everywhere if bpp < 8 in the current implementation
		(because that's likely a little bit faster)
		NOTE: comments about padding bits are only relevant if bpp < 8
		*/
		static void Adam7_deinterlace(uint8* _out, uint8* _in, unsigned w, unsigned h, unsigned bpp) {
		  unsigned[7] passw = default, passh = default;
		  size_t[8] filter_passstart = default, padded_passstart = default, passstart = default;
		  unsigned i;

		  Adam7_getpassvalues(ref passw, ref passh, ref filter_passstart, ref padded_passstart, ref passstart, w, h, bpp);

		  if(bpp >= 8) {
		    for(i = 0; i != 7; ++i) {
		      unsigned x, y, b;
		      size_t bytewidth = bpp / 8u;
		      for(y = 0; y < passh[i]; ++y)
		      for(x = 0; x < passw[i]; ++x) {
		        size_t pixelinstart = passstart[i] + (y * passw[i] + x) * bytewidth;
		        size_t pixeloutstart = ((ADAM7_IY[i] + (size_t)y * ADAM7_DY[i]) * (size_t)w
		                             + ADAM7_IX[i] + (size_t)x * ADAM7_DX[i]) * bytewidth;
		        for(b = 0; b < bytewidth; ++b) {
		          _out[pixeloutstart + b] = _in[pixelinstart + b];
		        }
		      }
		    }
		  } else /*bpp < 8: Adam7 with pixels < 8 bit is a bit trickier: with bit pointers*/ {
		    for(i = 0; i != 7; ++i) {
		      unsigned x, y, b;
		      unsigned ilinebits = bpp * passw[i];
		      unsigned olinebits = bpp * w;
		      size_t obp, ibp; /*bit pointers (for out and in buffer)*/
		      for(y = 0; y < passh[i]; ++y)
		      for(x = 0; x < passw[i]; ++x) {
		        ibp = (8 * passstart[i]) + (y * ilinebits + x * bpp);
		        obp = (ADAM7_IY[i] + (size_t)y * ADAM7_DY[i]) * olinebits + (ADAM7_IX[i] + (size_t)x * ADAM7_DX[i]) * bpp;
		        for(b = 0; b < bpp; ++b) {
		          uint8 bit = readBitFromReversedStream(&ibp, _in);
		          setBitOfReversedStream(&obp, _out, bit);
		        }
		      }
		    }
		  }
		}

		static void removePaddingBits(uint8* _out, uint8* _in,
		                              size_t olinebits, size_t ilinebits, unsigned h) {
		  /*
		  After filtering there are still padding bits if scanlines have non multiple of 8 bit amounts. They need
		  to be removed (except at last scanline of (Adam7-reduced) image) before working with pure image buffers
		  for the Adam7 code, the color convert code and the output to the user.
		  in and out are allowed to be the same buffer, in may also be higher but still overlapping; in must
		  have >= ilinebits*h bits, out must have >= olinebits*h bits, olinebits must be <= ilinebits
		  also used to move bits after earlier such operations happened, e.g. in a sequence of reduced images from Adam7
		  only useful if (ilinebits - olinebits) is a value in the range 1..7
		  */
		  unsigned y;
		  size_t diff = ilinebits - olinebits;
		  size_t ibp = 0, obp = 0; /*input and output bit pointers*/
		  for(y = 0; y < h; ++y) {
		    size_t x;
		    for(x = 0; x < olinebits; ++x) {
		      uint8 bit = readBitFromReversedStream(&ibp, _in);
		      setBitOfReversedStream(&obp, _out, bit);
		    }
		    ibp += diff;
		  }
		}

		/*out must be buffer big enough to contain full image, and in must contain the full decompressed data from
		the IDAT chunks (with filter index bytes and possible padding bits)
		return value is error*/
		static unsigned postProcessScanlines(uint8* _out, uint8* _in,
		                                     unsigned w, unsigned h, LodePNGInfo* info_png) {
		  /*
		  This function converts the filtered-padded-interlaced data into pure 2D image buffer with the PNG's colortype.
		  Steps:
		  *) if no Adam7: 1) unfilter 2) remove padding bits (= possible extra bits per scanline if bpp < 8)
		  *) if adam7: 1) 7x unfilter 2) 7x remove padding bits 3) Adam7_deinterlace
		  NOTE: the in buffer will be overwritten with intermediate data!
		  */
		  unsigned bpp = lodepng_get_bpp(&info_png.color);
		  if(bpp == 0) return 31; /*error: invalid colortype*/

		  if(info_png.interlace_method == 0) {
		    if(bpp < 8 && w * bpp != ((w * bpp + 7u) / 8u) * 8u) {
		      CERROR_TRY_RETURN!(unfilter(_in, _in, w, h, bpp));
		      removePaddingBits(_out, _in, w * bpp, ((w * bpp + 7u) / 8u) * 8u, h);
		    }
		    /*we can immediately filter into the out buffer, no other steps needed*/
		    else CERROR_TRY_RETURN!(unfilter(_out, _in, w, h, bpp));
		  } else /*interlace_method is 1 (Adam7)*/ {
		    unsigned[7] passw = default, passh = default; size_t[8] filter_passstart = default, padded_passstart = default, passstart = default;
		    unsigned i;

		    Adam7_getpassvalues(ref passw, ref passh, ref filter_passstart, ref padded_passstart, ref passstart, w, h, bpp);

		    for(i = 0; i != 7; ++i) {
		      CERROR_TRY_RETURN!(unfilter(&_in[padded_passstart[i]], &_in[filter_passstart[i]], passw[i], passh[i], bpp));
		      /*TODO: possible efficiency improvement: if in this reduced image the bits fit nicely in 1 scanline,
		      move bytes instead of bits or move not at all*/
		      if(bpp < 8) {
		        /*remove padding bits in scanlines; after this there still may be padding
		        bits between the different reduced images: each reduced image still starts nicely at a byte*/
		        removePaddingBits(&_in[passstart[i]], &_in[padded_passstart[i]], passw[i] * bpp,
		                          ((passw[i] * bpp + 7u) / 8u) * 8u, passh[i]);
		      }
		    }

		    Adam7_deinterlace(_out, _in, w, h, bpp);
		  }

		  return 0;
		}

		static unsigned readChunk_PLTE(LodePNGColorMode* color, uint8* data, size_t chunkLength) {
		  unsigned pos = 0, i;
		  color.palettesize = chunkLength / 3u;
		  if(color.palettesize == 0 || color.palettesize > 256) return 38; /*error: palette too small or big*/
		  lodepng_color_mode_alloc_palette(color);
		  if(color.palette == null && color.palettesize != 0) {
		    color.palettesize = 0;
		    return 83; /*alloc fail*/
		  }

		  for(i = 0; i != color.palettesize; ++i) {
		    color.palette[4 * i + 0] = data[pos++]; /*R*/
		    color.palette[4 * i + 1] = data[pos++]; /*G*/
		    color.palette[4 * i + 2] = data[pos++]; /*B*/
		    color.palette[4 * i + 3] = 255; /*alpha*/
		  }

		  return 0; /* OK */
		}

		static unsigned readChunk_tRNS(LodePNGColorMode* color, uint8* data, size_t chunkLength) {
		  unsigned i;
		  if(color.colortype == .LCT_PALETTE) {
		    /*error: more alpha values given than there are palette entries*/
		    if(chunkLength > color.palettesize) return 39;

		    for(i = 0; i != chunkLength; ++i) color.palette[4 * i + 3] = data[i];
		  } else if(color.colortype == .LCT_GREY) {
		    /*error: this chunk must be 2 bytes for grayscale image*/
		    if(chunkLength != 2) return 30;

		    color.key_defined = true;
		    color.key_r = color.key_g = color.key_b = 256u * data[0] + data[1];
		  } else if(color.colortype == .LCT_RGB) {
		    /*error: this chunk must be 6 bytes for RGB image*/
		    if(chunkLength != 6) return 41;

		    color.key_defined = true;
		    color.key_r = 256u * data[0] + data[1];
		    color.key_g = 256u * data[2] + data[3];
		    color.key_b = 256u * data[4] + data[5];
		  }
		  else return 42; /*error: tRNS chunk not allowed for other color models*/

		  return 0; /* OK */
		}


#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		/*background color chunk (bKGD)*/
		static unsigned readChunk_bKGD(LodePNGInfo* info, const uint8* data, size_t chunkLength) {
		  if(info.color.colortype == LCT_PALETTE) {
		    /*error: this chunk must be 1 byte for indexed color image*/
		    if(chunkLength != 1) return 43;

		    /*error: invalid palette index, or maybe this chunk appeared before PLTE*/
		    if(data[0] >= info.color.palettesize) return 103;

		    info.background_defined = 1;
		    info.background_r = info.background_g = info.background_b = data[0];
		  } else if(info.color.colortype == LCT_GREY || info.color.colortype == LCT_GREY_ALPHA) {
		    /*error: this chunk must be 2 bytes for grayscale image*/
		    if(chunkLength != 2) return 44;

		    /*the values are truncated to bitdepth in the PNG file*/
		    info.background_defined = 1;
		    info.background_r = info.background_g = info.background_b = 256u * data[0] + data[1];
		  } else if(info.color.colortype == LCT_RGB || info.color.colortype == LCT_RGBA) {
		    /*error: this chunk must be 6 bytes for grayscale image*/
		    if(chunkLength != 6) return 45;

		    /*the values are truncated to bitdepth in the PNG file*/
		    info.background_defined = 1;
		    info.background_r = 256u * data[0] + data[1];
		    info.background_g = 256u * data[2] + data[3];
		    info.background_b = 256u * data[4] + data[5];
		  }

		  return 0; /* OK */
		}

		/*text chunk (tEXt)*/
		static unsigned readChunk_tEXt(LodePNGInfo* info, const uint8* data, size_t chunkLength) {
		  unsigned error = 0;
		  char *key = 0, *str = 0;

		  while(!error) /*not really a while loop, only used to break on error*/ {
		    unsigned length, string2_begin;

		    length = 0;
		    while(length < chunkLength && data[length] != 0) ++length;
		    /*even though it's not allowed by the standard, no error is thrown if
		    there's no null termination char, if the text is empty*/
		    if(length < 1 || length > 79) CCERROR_BREAK!(error, error, 89); /*keyword too short or long*/

		    key = (char*)lodepng_malloc(length + 1);
		    if(!key) CCERROR_BREAK!(error, error, 83); /*alloc fail*/

		    lodepng_memcpy(key, data, length);
		    key[length] = 0;

		    string2_begin = length + 1; /*skip keyword null terminator*/

		    length = (unsigned)(chunkLength < string2_begin ? 0 : chunkLength - string2_begin);
		    str = (char*)lodepng_malloc(length + 1);
		    if(!str) CCERROR_BREAK!(error, error, 83); /*alloc fail*/

		    lodepng_memcpy(str, data + string2_begin, length);
		    str[length] = 0;

		    error = lodepng_add_text(info, key, str);

		    break;
		  }

		  lodepng_free(key);
		  lodepng_free(str);

		  return error;
		}

		/*compressed text chunk (zTXt)*/
		static unsigned readChunk_zTXt(LodePNGInfo* info, const LodePNGDecoderSettings* decoder,
		                               const uint8* data, size_t chunkLength) {
		  unsigned error = 0;

		  /*copy the object to change parameters in it*/
		  LodePNGDecompressSettings zlibsettings = decoder.zlibsettings;

		  unsigned length, string2_begin;
		  char *key = 0;
		  uint8* str = 0;
		  size_t size = 0;

		  while(!error) /*not really a while loop, only used to break on error*/ {
		    for(length = 0; length < chunkLength && data[length] != 0; ++length) ;
		    if(length + 2 >= chunkLength) CCERROR_BREAK!(error, error, 75); /*no null termination, corrupt?*/
		    if(length < 1 || length > 79) CCERROR_BREAK!(error, error, 89); /*keyword too short or long*/

		    key = (char*)lodepng_malloc(length + 1);
		    if(!key) CCERROR_BREAK!(error, error, 83); /*alloc fail*/

		    lodepng_memcpy(key, data, length);
		    key[length] = 0;

		    if(data[length + 1] != 0) CCERROR_BREAK!(error, error, 72); /*the 0 byte indicating compression must be 0*/

		    string2_begin = length + 2;
		    if(string2_begin > chunkLength) CCERROR_BREAK!(error, error, 75); /*no null termination, corrupt?*/

		    length = (unsigned)chunkLength - string2_begin;
		    zlibsettings.max_output_size = decoder.max_text_size;
		    /*will fail if zlib error, e.g. if length is too small*/
		    error = zlib_decompress(&str, &size, 0, &data[string2_begin],
		                            length, &zlibsettings);
		    /*error: compressed text larger than  decoder.max_text_size*/
		    if(error && size > zlibsettings.max_output_size) error = 112;
		    if(error) break;
		    error = lodepng_add_text_sized(info, key, (char*)str, size);
		    break;
		  }

		  lodepng_free(key);
		  lodepng_free(str);

		  return error;
		}

		/*international text chunk (iTXt)*/
		static unsigned readChunk_iTXt(LodePNGInfo* info, const LodePNGDecoderSettings* decoder,
		                               const uint8* data, size_t chunkLength) {
		  unsigned error = 0;
		  unsigned i;

		  /*copy the object to change parameters in it*/
		  LodePNGDecompressSettings zlibsettings = decoder.zlibsettings;

		  unsigned length, begin, compressed;
		  char *key = 0, *langtag = 0, *transkey = 0;

		  while(!error) /*not really a while loop, only used to break on error*/ {
		    /*Quick check if the chunk length isn't too small. Even without check
		    it'd still fail with other error checks below if it's too short. This just gives a different error code.*/
		    if(chunkLength < 5) CCERROR_BREAK!(error, error, 30); /*iTXt chunk too short*/

		    /*read the key*/
		    for(length = 0; length < chunkLength && data[length] != 0; ++length) ;
		    if(length + 3 >= chunkLength) CCERROR_BREAK!(error, error, 75); /*no null termination char, corrupt?*/
		    if(length < 1 || length > 79) CCERROR_BREAK!(error, error, 89); /*keyword too short or long*/

		    key = (char*)lodepng_malloc(length + 1);
		    if(!key) CCERROR_BREAK!(error, error, 83); /*alloc fail*/

		    lodepng_memcpy(key, data, length);
		    key[length] = 0;

		    /*read the compression method*/
		    compressed = data[length + 1];
		    if(data[length + 2] != 0) CCERROR_BREAK!(error, error, 72); /*the 0 byte indicating compression must be 0*/

		    /*even though it's not allowed by the standard, no error is thrown if
		    there's no null termination char, if the text is empty for the next 3 texts*/

		    /*read the langtag*/
		    begin = length + 3;
		    length = 0;
		    for(i = begin; i < chunkLength && data[i] != 0; ++i) ++length;

		    langtag = (char*)lodepng_malloc(length + 1);
		    if(!langtag) CCERROR_BREAK!(error, error, 83); /*alloc fail*/

		    lodepng_memcpy(langtag, data + begin, length);
		    langtag[length] = 0;

		    /*read the transkey*/
		    begin += length + 1;
		    length = 0;
		    for(i = begin; i < chunkLength && data[i] != 0; ++i) ++length;

		    transkey = (char*)lodepng_malloc(length + 1);
		    if(!transkey) CCERROR_BREAK!(error, error, 83); /*alloc fail*/

		    lodepng_memcpy(transkey, data + begin, length);
		    transkey[length] = 0;

		    /*read the actual text*/
		    begin += length + 1;

		    length = (unsigned)chunkLength < begin ? 0 : (unsigned)chunkLength - begin;

		    if(compressed) {
		      uint8* str = 0;
		      size_t size = 0;
		      zlibsettings.max_output_size = decoder.max_text_size;
		      /*will fail if zlib error, e.g. if length is too small*/
		      error = zlib_decompress(&str, &size, 0, &data[begin],
		                              length, &zlibsettings);
		      /*error: compressed text larger than  decoder.max_text_size*/
		      if(error && size > zlibsettings.max_output_size) error = 112;
		      if(!error) error = lodepng_add_itext_sized(info, key, langtag, transkey, (char*)str, size);
		      lodepng_free(str);
		    } else {
		      error = lodepng_add_itext_sized(info, key, langtag, transkey, (char*)(data + begin), length);
		    }

		    break;
		  }

		  lodepng_free(key);
		  lodepng_free(langtag);
		  lodepng_free(transkey);

		  return error;
		}

		static unsigned readChunk_tIME(LodePNGInfo* info, const uint8* data, size_t chunkLength) {
		  if(chunkLength != 7) return 73; /*invalid tIME chunk size*/

		  info.time_defined = 1;
		  info.time.year = 256u * data[0] + data[1];
		  info.time.month = data[2];
		  info.time.day = data[3];
		  info.time.hour = data[4];
		  info.time.minute = data[5];
		  info.time.second = data[6];

		  return 0; /* OK */
		}

		static unsigned readChunk_pHYs(LodePNGInfo* info, const uint8* data, size_t chunkLength) {
		  if(chunkLength != 9) return 74; /*invalid pHYs chunk size*/

		  info.phys_defined = 1;
		  info.phys_x = 16777216u * data[0] + 65536u * data[1] + 256u * data[2] + data[3];
		  info.phys_y = 16777216u * data[4] + 65536u * data[5] + 256u * data[6] + data[7];
		  info.phys_unit = data[8];

		  return 0; /* OK */
		}

		static unsigned readChunk_gAMA(LodePNGInfo* info, const uint8* data, size_t chunkLength) {
		  if(chunkLength != 4) return 96; /*invalid gAMA chunk size*/

		  info.gama_defined = 1;
		  info.gama_gamma = 16777216u * data[0] + 65536u * data[1] + 256u * data[2] + data[3];

		  return 0; /* OK */
		}

		static unsigned readChunk_cHRM(LodePNGInfo* info, const uint8* data, size_t chunkLength) {
		  if(chunkLength != 32) return 97; /*invalid cHRM chunk size*/

		  info.chrm_defined = 1;
		  info.chrm_white_x = 16777216u * data[ 0] + 65536u * data[ 1] + 256u * data[ 2] + data[ 3];
		  info.chrm_white_y = 16777216u * data[ 4] + 65536u * data[ 5] + 256u * data[ 6] + data[ 7];
		  info.chrm_red_x   = 16777216u * data[ 8] + 65536u * data[ 9] + 256u * data[10] + data[11];
		  info.chrm_red_y   = 16777216u * data[12] + 65536u * data[13] + 256u * data[14] + data[15];
		  info.chrm_green_x = 16777216u * data[16] + 65536u * data[17] + 256u * data[18] + data[19];
		  info.chrm_green_y = 16777216u * data[20] + 65536u * data[21] + 256u * data[22] + data[23];
		  info.chrm_blue_x  = 16777216u * data[24] + 65536u * data[25] + 256u * data[26] + data[27];
		  info.chrm_blue_y  = 16777216u * data[28] + 65536u * data[29] + 256u * data[30] + data[31];

		  return 0; /* OK */
		}

		static unsigned readChunk_sRGB(LodePNGInfo* info, const uint8* data, size_t chunkLength) {
		  if(chunkLength != 1) return 98; /*invalid sRGB chunk size (this one is never ignored)*/

		  info.srgb_defined = 1;
		  info.srgb_intent = data[0];

		  return 0; /* OK */
		}

		static unsigned readChunk_iCCP(LodePNGInfo* info, const LodePNGDecoderSettings* decoder,
		                               const uint8* data, size_t chunkLength) {
		  unsigned error = 0;
		  unsigned i;
		  size_t size = 0;
		  /*copy the object to change parameters in it*/
		  LodePNGDecompressSettings zlibsettings = decoder.zlibsettings;

		  unsigned length, string2_begin;

		  info.iccp_defined = 1;
		  if(info.iccp_name) lodepng_clear_icc(info);

		  for(length = 0; length < chunkLength && data[length] != 0; ++length) ;
		  if(length + 2 >= chunkLength) return 75; /*no null termination, corrupt?*/
		  if(length < 1 || length > 79) return 89; /*keyword too short or long*/

		  info.iccp_name = (char*)lodepng_malloc(length + 1);
		  if(!info.iccp_name) return 83; /*alloc fail*/

		  info.iccp_name[length] = 0;
		  for(i = 0; i != length; ++i) info.iccp_name[i] = (char)data[i];

		  if(data[length + 1] != 0) return 72; /*the 0 byte indicating compression must be 0*/

		  string2_begin = length + 2;
		  if(string2_begin > chunkLength) return 75; /*no null termination, corrupt?*/

		  length = (unsigned)chunkLength - string2_begin;
		  zlibsettings.max_output_size = decoder.max_icc_size;
		  error = zlib_decompress(&info.iccp_profile, &size, 0,
		                          &data[string2_begin],
		                          length, &zlibsettings);
		  /*error: ICC profile larger than  decoder.max_icc_size*/
		  if(error && size > zlibsettings.max_output_size) error = 113;
		  info.iccp_profile_size = size;
		  if(!error && !info.iccp_profile_size) error = 100; /*invalid ICC profile size*/
		  return error;
		}
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/

		unsigned lodepng_inspect_chunk(LodePNGState* state, size_t pos,
		                               uint8* _in, size_t insize) {
		  uint8* chunk = _in + pos;
		  unsigned chunkLength;
		  uint8* data;
		  unsigned unhandled = 0;
		  unsigned error = 0;

		  if(pos + 4 > insize) return 30;
		  chunkLength = lodepng_chunk_length(chunk);
		  if(chunkLength > 2147483647) return 63;
		  data = lodepng_chunk_data_const(chunk);
		  if(data + chunkLength + 4 > _in + insize) return 30;

		  if(lodepng_chunk_type_equals(chunk, "PLTE")) {
		    error = readChunk_PLTE(&state.info_png.color, data, chunkLength);
		  } else if(lodepng_chunk_type_equals(chunk, "tRNS")) {
		    error = readChunk_tRNS(&state.info_png.color, data, chunkLength);
#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		  } else if(lodepng_chunk_type_equals(chunk, "bKGD")) {
		    error = readChunk_bKGD(&state.info_png, data, chunkLength);
		  } else if(lodepng_chunk_type_equals(chunk, "tEXt")) {
		    error = readChunk_tEXt(&state.info_png, data, chunkLength);
		  } else if(lodepng_chunk_type_equals(chunk, "zTXt")) {
		    error = readChunk_zTXt(&state.info_png, &state.decoder, data, chunkLength);
		  } else if(lodepng_chunk_type_equals(chunk, "iTXt")) {
		    error = readChunk_iTXt(&state.info_png, &state.decoder, data, chunkLength);
		  } else if(lodepng_chunk_type_equals(chunk, "tIME")) {
		    error = readChunk_tIME(&state.info_png, data, chunkLength);
		  } else if(lodepng_chunk_type_equals(chunk, "pHYs")) {
		    error = readChunk_pHYs(&state.info_png, data, chunkLength);
		  } else if(lodepng_chunk_type_equals(chunk, "gAMA")) {
		    error = readChunk_gAMA(&state.info_png, data, chunkLength);
		  } else if(lodepng_chunk_type_equals(chunk, "cHRM")) {
		    error = readChunk_cHRM(&state.info_png, data, chunkLength);
		  } else if(lodepng_chunk_type_equals(chunk, "sRGB")) {
		    error = readChunk_sRGB(&state.info_png, data, chunkLength);
		  } else if(lodepng_chunk_type_equals(chunk, "iCCP")) {
		    error = readChunk_iCCP(&state.info_png, &state.decoder, data, chunkLength);
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
		  } else {
		    /* unhandled chunk is ok (is not an error) */
		    unhandled = 1;
		  }

		  if(error == 0 && unhandled == 0 && state.decoder.ignore_crc == 0) {
		    if(lodepng_chunk_check_crc(chunk)) return 57; /*invalid CRC*/
		  }

		  return error;
		}

		/*read a PNG, the result will be in the same color type as the PNG (hence "generic")*/
		static void decodeGeneric(uint8** _out, unsigned* w, unsigned* h,
		                          LodePNGState* state,
		                          uint8* _in, size_t insize) {
		  uint8 IEND = 0;
		  uint8* chunk;
		  uint8* idat; /*the data from idat chunks, zlib compressed*/
		  size_t idatsize = 0;
		  uint8* scanlines = null;
		  size_t scanlines_size = 0, expected_size = 0;
		  size_t outsize = 0;

		  /*for unknown chunk order*/
		  unsigned unknown = 0;
#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		  unsigned critical_pos = 1; /*1 = after IHDR, 2 = after PLTE, 3 = after IDAT*/
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/


		  /* safe output values in case error happens */
		  *_out = null;
		  *w = *h = 0;

		  state.error = lodepng_inspect(w, h, state, _in, insize); /*reads header and resets other parameters in state.info_png*/
		  if(state.error != 0) return;

		  if(lodepng_pixel_overflow(*w, *h, &state.info_png.color, &state.info_raw)) {
		    CERROR_RETURN!(state.error, 92); /*overflow possible due to amount of pixels*/
		  }

		  /*the input filesize is a safe upper bound for the sum of idat chunks size*/
		  idat = (uint8*)lodepng_malloc(insize);
		  if(idat == null) CERROR_RETURN!(state.error, 83); /*alloc fail*/

		  chunk = &_in[33]; /*first byte of the first chunk after the header*/

		  /*loop through the chunks, ignoring unknown chunks and stopping at IEND chunk.
		  IDAT data is put at the start of the in buffer*/
		  while(IEND == 0 && state.error == 0) {
		    unsigned chunkLength;
		    uint8* data; /*the data in the chunk*/

		    /*error: size of the in buffer too small to contain next chunk*/
		    if((size_t)((chunk - _in) + 12) > insize || chunk < _in) {
		      if(state.decoder.ignore_end != 0) break; /*other errors may still happen though*/
		      CERROR_BREAK!(state.error, 30);
		    }

		    /*length of the data of the chunk, excluding the length bytes, chunk type and CRC bytes*/
		    chunkLength = lodepng_chunk_length(chunk);
		    /*error: chunk length larger than the max PNG chunk size*/
		    if(chunkLength > 2147483647) {
		      if(state.decoder.ignore_end != 0) break; /*other errors may still happen though*/
		      CERROR_BREAK!(state.error, 63);
		    }

		    if((size_t)((chunk - _in) + chunkLength + 12) > insize || (chunk + chunkLength + 12) < _in) {
		      CERROR_BREAK!(state.error, 64); /*error: size of the in buffer too small to contain next chunk*/
		    }

		    data = lodepng_chunk_data_const(chunk);

		    unknown = 0;

		    /*IDAT chunk, containing compressed image data*/
		    if(lodepng_chunk_type_equals(chunk, "IDAT")) {
		      size_t newsize = default;
		      if(lodepng_addofl(idatsize, chunkLength, &newsize)) CERROR_BREAK!(state.error, 95);
		      if(newsize > insize) CERROR_BREAK!(state.error, 95);
		      lodepng_memcpy(idat + idatsize, data, chunkLength);
		      idatsize += chunkLength;
#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		      critical_pos = 3;
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
		    } else if(lodepng_chunk_type_equals(chunk, "IEND")) {
		      /*IEND chunk*/
		      IEND = 1;
		    } else if(lodepng_chunk_type_equals(chunk, "PLTE")) {
		      /*palette chunk (PLTE)*/
		      state.error = readChunk_PLTE(&state.info_png.color, data, chunkLength);
		      if(state.error != 0) break;
#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		      critical_pos = 2;
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
		    } else if(lodepng_chunk_type_equals(chunk, "tRNS")) {
		      /*palette transparency chunk (tRNS). Even though this one is an ancillary chunk , it is still compiled
		      in without 'LODEPNG_COMPILE_ANCILLARY_CHUNKS' because it contains essential color information that
		      affects the alpha channel of pixels. */
		      state.error = readChunk_tRNS(&state.info_png.color, data, chunkLength);
		      if(state.error != 0) break;
#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		      /*background color chunk (bKGD)*/
		    } else if(lodepng_chunk_type_equals(chunk, "bKGD")) {
		      state.error = readChunk_bKGD(&state.info_png, data, chunkLength);
		      if(state.error) break;
		    } else if(lodepng_chunk_type_equals(chunk, "tEXt")) {
		      /*text chunk (tEXt)*/
		      if(state.decoder.read_text_chunks) {
		        state.error = readChunk_tEXt(&state.info_png, data, chunkLength);
		        if(state.error) break;
		      }
		    } else if(lodepng_chunk_type_equals(chunk, "zTXt")) {
		      /*compressed text chunk (zTXt)*/
		      if(state.decoder.read_text_chunks) {
		        state.error = readChunk_zTXt(&state.info_png, &state.decoder, data, chunkLength);
		        if(state.error) break;
		      }
		    } else if(lodepng_chunk_type_equals(chunk, "iTXt")) {
		      /*international text chunk (iTXt)*/
		      if(state.decoder.read_text_chunks) {
		        state.error = readChunk_iTXt(&state.info_png, &state.decoder, data, chunkLength);
		        if(state.error) break;
		      }
		    } else if(lodepng_chunk_type_equals(chunk, "tIME")) {
		      state.error = readChunk_tIME(&state.info_png, data, chunkLength);
		      if(state.error) break;
		    } else if(lodepng_chunk_type_equals(chunk, "pHYs")) {
		      state.error = readChunk_pHYs(&state.info_png, data, chunkLength);
		      if(state.error) break;
		    } else if(lodepng_chunk_type_equals(chunk, "gAMA")) {
		      state.error = readChunk_gAMA(&state.info_png, data, chunkLength);
		      if(state.error) break;
		    } else if(lodepng_chunk_type_equals(chunk, "cHRM")) {
		      state.error = readChunk_cHRM(&state.info_png, data, chunkLength);
		      if(state.error) break;
		    } else if(lodepng_chunk_type_equals(chunk, "sRGB")) {
		      state.error = readChunk_sRGB(&state.info_png, data, chunkLength);
		      if(state.error) break;
		    } else if(lodepng_chunk_type_equals(chunk, "iCCP")) {
		      state.error = readChunk_iCCP(&state.info_png, &state.decoder, data, chunkLength);
		      if(state.error) break;
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
		    } else /*it's not an implemented chunk type, so ignore it: skip over the data*/ {
		      /*error: unknown critical chunk (5th bit of first byte of chunk type is 0)*/
		      if(state.decoder.ignore_critical == 0 && !lodepng_chunk_ancillary(chunk)) {
		        CERROR_BREAK!(state.error, 69);
		      }

		      unknown = 1;
#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		      if(state.decoder.remember_unknown_chunks) {
		        state.error = lodepng_chunk_append(&state.info_png.unknown_chunks_data[critical_pos - 1],
		                                            &state.info_png.unknown_chunks_size[critical_pos - 1], chunk);
		        if(state.error) break;
		      }
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
		    }

		    if(state.decoder.ignore_crc == 0 && unknown == 0) /*check CRC if wanted, only on known chunk types*/ {
		      if(lodepng_chunk_check_crc(chunk)) CERROR_BREAK!(state.error, 57); /*invalid CRC*/
		    }

		    if(IEND == 0) chunk = lodepng_chunk_next_const(chunk, _in + insize);
		  }

		  if(state.error == 0 && state.info_png.color.colortype == .LCT_PALETTE && state.info_png.color.palette == null) {
		    state.error = 106; /* error: PNG file must have PLTE chunk if color type is palette */
		  }

		  if(state.error == 0) {
		    /*predict output size, to allocate exact size for output buffer to avoid more dynamic allocation.
		    If the decompressed size does not match the prediction, the image must be corrupt.*/
		    if(state.info_png.interlace_method == 0) {
		      size_t bpp = lodepng_get_bpp(&state.info_png.color);
		      expected_size = lodepng_get_raw_size_idat(*w, *h, bpp);
		    } else {
		      size_t bpp = lodepng_get_bpp(&state.info_png.color);
		      /*Adam-7 interlaced: expected size is the sum of the 7 sub-images sizes*/
		      expected_size = 0;
		      expected_size += lodepng_get_raw_size_idat((*w + 7) >> 3, (*h + 7) >> 3, bpp);
		      if(*w > 4) expected_size += lodepng_get_raw_size_idat((*w + 3) >> 3, (*h + 7) >> 3, bpp);
		      expected_size += lodepng_get_raw_size_idat((*w + 3) >> 2, (*h + 3) >> 3, bpp);
		      if(*w > 2) expected_size += lodepng_get_raw_size_idat((*w + 1) >> 2, (*h + 3) >> 2, bpp);
		      expected_size += lodepng_get_raw_size_idat((*w + 1) >> 1, (*h + 1) >> 2, bpp);
		      if(*w > 1) expected_size += lodepng_get_raw_size_idat((*w + 0) >> 1, (*h + 1) >> 1, bpp);
		      expected_size += lodepng_get_raw_size_idat((*w + 0), (*h + 0) >> 1, bpp);
		    }

		    state.error = zlib_decompress(&scanlines, &scanlines_size, expected_size, idat, idatsize, &state.decoder.zlibsettings);
		  }
		  if(state.error == 0 && scanlines_size != expected_size) state.error = 91; /*decompressed size doesn't match prediction*/
		  lodepng_free(idat);

		  if(state.error == 0) {
		    outsize = lodepng_get_raw_size(*w, *h, &state.info_png.color);
		    *_out = (uint8*)lodepng_malloc(outsize);
		    if(*_out == null) state.error = 83; /*alloc fail*/
		  }
		  if(state.error == 0) {
		    lodepng_memset(*_out, 0, outsize);
		    state.error = postProcessScanlines(*_out, scanlines, *w, *h, &state.info_png);
		  }
		  lodepng_free(scanlines);
		}

		static unsigned lodepng_decode(uint8** _out, unsigned* w, unsigned* h,
		                        LodePNGState* state,
		                        uint8* _in, size_t insize) {
		  *_out = null;
		  decodeGeneric(_out, w, h, state, _in, insize);
		  if(state.error != 0) return state.error;
		  if(state.decoder.color_convert == 0 || lodepng_color_mode_equal(&state.info_raw, &state.info_png.color)) {
		    /*same color type, no copying or converting of data needed*/
		    /*store the info_png color settings on the info_raw so that the info_raw still reflects what colortype
		    the raw image has to the end user*/
		    if(state.decoder.color_convert == 0) {
		      state.error = lodepng_color_mode_copy(&state.info_raw, &state.info_png.color);
		      if(state.error != 0) return state.error;
		    }
		  } else { /*color conversion needed*/
		    uint8* data = *_out;
		    size_t outsize;

		    /*TODO: check if this works according to the statement in the documentation: "The converter can convert
		    from grayscale input color type, to 8-bit grayscale or grayscale with alpha"*/
		    if(!(state.info_raw.colortype == .LCT_RGB || state.info_raw.colortype == .LCT_RGBA)
		       && !(state.info_raw.bitdepth == 8)) {
		      return 56; /*unsupported color mode conversion*/
		    }

		    outsize = lodepng_get_raw_size(*w, *h, &state.info_raw);
		    *_out = (uint8*)lodepng_malloc(outsize);
		    if((*_out) == null) {
		      state.error = 83; /*alloc fail*/
		    }
		    else state.error = lodepng_convert(*_out, data, &state.info_raw,
		                                        &state.info_png.color, *w, *h);
		    lodepng_free(data);
		  }
		  return state.error;
		}

		public static unsigned lodepng_decode_memory(uint8** _out, unsigned* w, unsigned* h, uint8* _in,
		                               size_t insize, LodePNGColorType colortype, unsigned bitdepth) {
		  unsigned error;
		  LodePNGState state;
		  lodepng_state_init(&state);
		  state.info_raw.colortype = colortype;
		  state.info_raw.bitdepth = bitdepth;
#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		  /*disable reading things that this function doesn't output*/
		  state.decoder.read_text_chunks = 0;
		  state.decoder.remember_unknown_chunks = 0;
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
		  error = lodepng_decode(_out, w, h, &state, _in, insize);
		  lodepng_state_cleanup(&state);
		  return error;
		}

		static unsigned lodepng_decode32(uint8** _out, unsigned* w, unsigned* h, uint8* _in, size_t insize) {
		  return lodepng_decode_memory(_out, w, h, _in, insize, .LCT_RGBA, 8);
		}

		static unsigned lodepng_decode24(uint8** _out, unsigned* w, unsigned* h, uint8* _in, size_t insize) {
		  return lodepng_decode_memory(_out, w, h, _in, insize, .LCT_RGB, 8);
		}

#if LODEPNG_COMPILE_DISK
		public static unsigned lodepng_decode_file(uint8** _out, unsigned* w, unsigned* h, char8* filename,
		                             LodePNGColorType colortype, unsigned bitdepth) {
		  uint8* buffer = null;
		  size_t buffersize = default;
		  unsigned error;
		  /* safe output values in case error happens */
		  *_out = null;
		  *w = *h = 0;
		  error = lodepng_load_file(&buffer, &buffersize, filename);
		  if(error == 0) error = lodepng_decode_memory(_out, w, h, buffer, buffersize, colortype, bitdepth);
		  lodepng_free(buffer);
		  return error;
		}

		static unsigned lodepng_decode32_file(uint8** _out, unsigned* w, unsigned* h, char8* filename) {
		  return lodepng_decode_file(_out, w, h, filename, .LCT_RGBA, 8);
		}

		static unsigned lodepng_decode24_file(uint8** _out, unsigned* w, unsigned* h, char8* filename) {
		  return lodepng_decode_file(_out, w, h, filename, .LCT_RGB, 8);
		}
#endif /*LODEPNG_COMPILE_DISK*/

		public static void lodepng_decoder_settings_init(LodePNGDecoderSettings* settings) {
		  settings.color_convert = 1;
#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		  settings.read_text_chunks = 1;
		  settings.remember_unknown_chunks = 0;
		  settings.max_text_size = 16777216;
		  settings.max_icc_size = 16777216; /* 16MB is much more than enough for any reasonable ICC profile */
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
		  settings.ignore_crc = 0;
		  settings.ignore_critical = 0;
		  settings.ignore_end = 0;
		  lodepng_decompress_settings_init(&settings.zlibsettings);
		}

#endif /*LODEPNG_COMPILE_DECODER*/

#if LODEPNG_COMPILE_DECODER || LODEPNG_COMPILE_ENCODER

		static void lodepng_state_init(LodePNGState* state) {
#if LODEPNG_COMPILE_DECODER
		  lodepng_decoder_settings_init(&state.decoder);
#endif /*LODEPNG_COMPILE_DECODER*/
#if LODEPNG_COMPILE_ENCODER
		  lodepng_encoder_settings_init(&state.encoder);
#endif /*LODEPNG_COMPILE_ENCODER*/
		  lodepng_color_mode_init(&state.info_raw);
		  lodepng_info_init(&state.info_png);
		  state.error = 1;
		}

		static void lodepng_state_cleanup(LodePNGState* state) {
		  lodepng_color_mode_cleanup(&state.info_raw);
		  lodepng_info_cleanup(&state.info_png);
		}

		static void lodepng_state_copy(LodePNGState* dest, LodePNGState* source) {
		  lodepng_state_cleanup(dest);
		  *dest = *source;
		  lodepng_color_mode_init(&dest.info_raw);
		  lodepng_info_init(&dest.info_png);
		  dest.error = lodepng_color_mode_copy(&dest.info_raw, &source.info_raw); if(dest.error != 0) return;
		  dest.error = lodepng_info_copy(&dest.info_png, &source.info_png); if(dest.error != 0) return;
		}

#endif /* defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_ENCODER) */

#if LODEPNG_COMPILE_ENCODER

		/* ////////////////////////////////////////////////////////////////////////// */
		/* / PNG Encoder                                                            / */
		/* ////////////////////////////////////////////////////////////////////////// */


		static unsigned writeSignature(ucvector* out) {
		  size_t pos = out.size;
		  const uint8 signature[] = {137, 80, 78, 71, 13, 10, 26, 10};
		  /*8 bytes PNG signature, aka the magic bytes*/
		  if(!ucvector_resize(out, out.size + 8)) return 83; /*alloc fail*/
		  lodepng_memcpy(out.data + pos, signature, 8);
		  return 0;
		}

		static unsigned addChunk_IHDR(ucvector* out, unsigned w, unsigned h,
		                              LodePNGColorType colortype, unsigned bitdepth, unsigned interlace_method) {
		  uint8 *chunk, *data;
		  CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 13, "IHDR"));
		  data = chunk + 8;

		  lodepng_set32bitInt(data + 0, w); /*width*/
		  lodepng_set32bitInt(data + 4, h); /*height*/
		  data[8] = (uint8)bitdepth; /*bit depth*/
		  data[9] = (uint8)colortype; /*color type*/
		  data[10] = 0; /*compression method*/
		  data[11] = 0; /*filter method*/
		  data[12] = interlace_method; /*interlace method*/

		  lodepng_chunk_generate_crc(chunk);
		  return 0;
		}

		/* only adds the chunk if needed (there is a key or palette with alpha) */
		static unsigned addChunk_PLTE(ucvector* out, const LodePNGColorMode* info) {
		  uint8* chunk;
		  size_t i, j = 8;

		  CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, info.palettesize * 3, "PLTE"));

		  for(i = 0; i != info.palettesize; ++i) {
		    /*add all channels except alpha channel*/
		    chunk[j++] = info.palette[i * 4 + 0];
		    chunk[j++] = info.palette[i * 4 + 1];
		    chunk[j++] = info.palette[i * 4 + 2];
		  }

		  lodepng_chunk_generate_crc(chunk);
		  return 0;
		}

		static unsigned addChunk_tRNS(ucvector* out, const LodePNGColorMode* info) {
		  uint8* chunk = 0;

		  if(info.colortype == LCT_PALETTE) {
		    size_t i, amount = info.palettesize;
		    /*the tail of palette values that all have 255 as alpha, does not have to be encoded*/
		    for(i = info.palettesize; i != 0; --i) {
		      if(info.palette[4 * (i - 1) + 3] != 255) break;
		      --amount;
		    }
		    if(amount) {
		      CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, amount, "tRNS"));
		      /*add the alpha channel values from the palette*/
		      for(i = 0; i != amount; ++i) chunk[8 + i] = info.palette[4 * i + 3];
		    }
		  } else if(info.colortype == LCT_GREY) {
		    if(info.key_defined) {
		      CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 2, "tRNS"));
		      chunk[8] = (uint8)(info.key_r >> 8);
		      chunk[9] = (uint8)(info.key_r & 255);
		    }
		  } else if(info.colortype == LCT_RGB) {
		    if(info.key_defined) {
		      CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 6, "tRNS"));
		      chunk[8] = (uint8)(info.key_r >> 8);
		      chunk[9] = (uint8)(info.key_r & 255);
		      chunk[10] = (uint8)(info.key_g >> 8);
		      chunk[11] = (uint8)(info.key_g & 255);
		      chunk[12] = (uint8)(info.key_b >> 8);
		      chunk[13] = (uint8)(info.key_b & 255);
		    }
		  }

		  if(chunk) lodepng_chunk_generate_crc(chunk);
		  return 0;
		}

		static unsigned addChunk_IDAT(ucvector* out, const uint8* data, size_t datasize,
		                              LodePNGCompressSettings* zlibsettings) {
		  unsigned error = 0;
		  uint8* zlib = 0;
		  size_t zlibsize = 0;

		  error = zlib_compress(&zlib, &zlibsize, data, datasize, zlibsettings);
		  if(!error) {
		    error = lodepng_chunk_createv(out, zlibsize, "IDAT", zlib);
		  }
		  lodepng_free(zlib);
		  return error;
		}

		static unsigned addChunk_IEND(ucvector* out) {
		  return lodepng_chunk_createv(out, 0, "IEND", 0);
		}

#if LODEPNG_COMPILE_ANCILLARY_CHUNKS

		static unsigned addChunk_tEXt(ucvector* out, const char* keyword, const char* textstring) {
		  uint8* chunk = 0;
		  size_t keysize = lodepng_strlen(keyword), textsize = lodepng_strlen(textstring);
		  size_t size = keysize + 1 + textsize;
		  if(keysize < 1 || keysize > 79) return 89; /*error: invalid keyword size*/
		  CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, size, "tEXt"));
		  lodepng_memcpy(chunk + 8, keyword, keysize);
		  chunk[8 + keysize] = 0; /*null termination char*/
		  lodepng_memcpy(chunk + 9 + keysize, textstring, textsize);
		  lodepng_chunk_generate_crc(chunk);
		  return 0;
		}

		static unsigned addChunk_zTXt(ucvector* out, const char* keyword, const char* textstring,
		                              LodePNGCompressSettings* zlibsettings) {
		  unsigned error = 0;
		  uint8* chunk = 0;
		  uint8* compressed = 0;
		  size_t compressedsize = 0;
		  size_t textsize = lodepng_strlen(textstring);
		  size_t keysize = lodepng_strlen(keyword);
		  if(keysize < 1 || keysize > 79) return 89; /*error: invalid keyword size*/

		  error = zlib_compress(&compressed, &compressedsize,
		                        (const uint8*)textstring, textsize, zlibsettings);
		  if(!error) {
		    size_t size = keysize + 2 + compressedsize;
		    error = lodepng_chunk_init(&chunk, out, size, "zTXt");
		  }
		  if(!error) {
		    lodepng_memcpy(chunk + 8, keyword, keysize);
		    chunk[8 + keysize] = 0; /*null termination char*/
		    chunk[9 + keysize] = 0; /*compression method: 0*/
		    lodepng_memcpy(chunk + 10 + keysize, compressed, compressedsize);
		    lodepng_chunk_generate_crc(chunk);
		  }

		  lodepng_free(compressed);
		  return error;
		}

		static unsigned addChunk_iTXt(ucvector* out, unsigned compress, const char* keyword, const char* langtag,
		                              const char* transkey, const char* textstring, LodePNGCompressSettings* zlibsettings) {
		  unsigned error = 0;
		  uint8* chunk = 0;
		  uint8* compressed = 0;
		  size_t compressedsize = 0;
		  size_t textsize = lodepng_strlen(textstring);
		  size_t keysize = lodepng_strlen(keyword), langsize = lodepng_strlen(langtag), transsize = lodepng_strlen(transkey);

		  if(keysize < 1 || keysize > 79) return 89; /*error: invalid keyword size*/

		  if(compress) {
		    error = zlib_compress(&compressed, &compressedsize,
		                          (const uint8*)textstring, textsize, zlibsettings);
		  }
		  if(!error) {
		    size_t size = keysize + 3 + langsize + 1 + transsize + 1 + (compress ? compressedsize : textsize);
		    error = lodepng_chunk_init(&chunk, out, size, "iTXt");
		  }
		  if(!error) {
		    size_t pos = 8;
		    lodepng_memcpy(chunk + pos, keyword, keysize);
		    pos += keysize;
		    chunk[pos++] = 0; /*null termination char*/
		    chunk[pos++] = (compress ? 1 : 0); /*compression flag*/
		    chunk[pos++] = 0; /*compression method: 0*/
		    lodepng_memcpy(chunk + pos, langtag, langsize);
		    pos += langsize;
		    chunk[pos++] = 0; /*null termination char*/
		    lodepng_memcpy(chunk + pos, transkey, transsize);
		    pos += transsize;
		    chunk[pos++] = 0; /*null termination char*/
		    if(compress) {
		      lodepng_memcpy(chunk + pos, compressed, compressedsize);
		    } else {
		      lodepng_memcpy(chunk + pos, textstring, textsize);
		    }
		    lodepng_chunk_generate_crc(chunk);
		  }

		  lodepng_free(compressed);
		  return error;
		}

		static unsigned addChunk_bKGD(ucvector* out, const LodePNGInfo* info) {
		  uint8* chunk = 0;
		  if(info.color.colortype == LCT_GREY || info.color.colortype == LCT_GREY_ALPHA) {
		    CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 2, "bKGD"));
		    chunk[8] = (uint8)(info.background_r >> 8);
		    chunk[9] = (uint8)(info.background_r & 255);
		  } else if(info.color.colortype == LCT_RGB || info.color.colortype == LCT_RGBA) {
		    CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 6, "bKGD"));
		    chunk[8] = (uint8)(info.background_r >> 8);
		    chunk[9] = (uint8)(info.background_r & 255);
		    chunk[10] = (uint8)(info.background_g >> 8);
		    chunk[11] = (uint8)(info.background_g & 255);
		    chunk[12] = (uint8)(info.background_b >> 8);
		    chunk[13] = (uint8)(info.background_b & 255);
		  } else if(info.color.colortype == LCT_PALETTE) {
		    CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 1, "bKGD"));
		    chunk[8] = (uint8)(info.background_r & 255); /*palette index*/
		  }
		  if(chunk) lodepng_chunk_generate_crc(chunk);
		  return 0;
		}

		static unsigned addChunk_tIME(ucvector* out, const LodePNGTime* time) {
		  uint8* chunk;
		  CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 7, "tIME"));
		  chunk[8] = (uint8)(time.year >> 8);
		  chunk[9] = (uint8)(time.year & 255);
		  chunk[10] = (uint8)time.month;
		  chunk[11] = (uint8)time.day;
		  chunk[12] = (uint8)time.hour;
		  chunk[13] = (uint8)time.minute;
		  chunk[14] = (uint8)time.second;
		  lodepng_chunk_generate_crc(chunk);
		  return 0;
		}

		static unsigned addChunk_pHYs(ucvector* out, const LodePNGInfo* info) {
		  uint8* chunk;
		  CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 9, "pHYs"));
		  lodepng_set32bitInt(chunk + 8, info.phys_x);
		  lodepng_set32bitInt(chunk + 12, info.phys_y);
		  chunk[16] = info.phys_unit;
		  lodepng_chunk_generate_crc(chunk);
		  return 0;
		}

		static unsigned addChunk_gAMA(ucvector* out, const LodePNGInfo* info) {
		  uint8* chunk;
		  CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 4, "gAMA"));
		  lodepng_set32bitInt(chunk + 8, info.gama_gamma);
		  lodepng_chunk_generate_crc(chunk);
		  return 0;
		}

		static unsigned addChunk_cHRM(ucvector* out, const LodePNGInfo* info) {
		  uint8* chunk;
		  CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 32, "cHRM"));
		  lodepng_set32bitInt(chunk + 8, info.chrm_white_x);
		  lodepng_set32bitInt(chunk + 12, info.chrm_white_y);
		  lodepng_set32bitInt(chunk + 16, info.chrm_red_x);
		  lodepng_set32bitInt(chunk + 20, info.chrm_red_y);
		  lodepng_set32bitInt(chunk + 24, info.chrm_green_x);
		  lodepng_set32bitInt(chunk + 28, info.chrm_green_y);
		  lodepng_set32bitInt(chunk + 32, info.chrm_blue_x);
		  lodepng_set32bitInt(chunk + 36, info.chrm_blue_y);
		  lodepng_chunk_generate_crc(chunk);
		  return 0;
		}

		static unsigned addChunk_sRGB(ucvector* out, const LodePNGInfo* info) {
		  uint8 data = info.srgb_intent;
		  return lodepng_chunk_createv(out, 1, "sRGB", &data);
		}

		static unsigned addChunk_iCCP(ucvector* out, const LodePNGInfo* info, LodePNGCompressSettings* zlibsettings) {
		  unsigned error = 0;
		  uint8* chunk = 0;
		  uint8* compressed = 0;
		  size_t compressedsize = 0;
		  size_t keysize = lodepng_strlen(info.iccp_name);

		  if(keysize < 1 || keysize > 79) return 89; /*error: invalid keyword size*/
		  error = zlib_compress(&compressed, &compressedsize,
		                        info.iccp_profile, info.iccp_profile_size, zlibsettings);
		  if(!error) {
		    size_t size = keysize + 2 + compressedsize;
		    error = lodepng_chunk_init(&chunk, out, size, "iCCP");
		  }
		  if(!error) {
		    lodepng_memcpy(chunk + 8, info.iccp_name, keysize);
		    chunk[8 + keysize] = 0; /*null termination char*/
		    chunk[9 + keysize] = 0; /*compression method: 0*/
		    lodepng_memcpy(chunk + 10 + keysize, compressed, compressedsize);
		    lodepng_chunk_generate_crc(chunk);
		  }

		  lodepng_free(compressed);
		  return error;
		}

#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/

		static void filterScanline(uint8* out, const uint8* scanline, const uint8* prevline,
		                           size_t length, size_t bytewidth, uint8 filterType) {
		  size_t i;
		  switch(filterType) {
		    case 0: /*None*/
		      for(i = 0; i != length; ++i) out[i] = scanline[i];
		      break;
		    case 1: /*Sub*/
		      for(i = 0; i != bytewidth; ++i) out[i] = scanline[i];
		      for(i = bytewidth; i < length; ++i) out[i] = scanline[i] - scanline[i - bytewidth];
		      break;
		    case 2: /*Up*/
		      if(prevline) {
		        for(i = 0; i != length; ++i) out[i] = scanline[i] - prevline[i];
		      } else {
		        for(i = 0; i != length; ++i) out[i] = scanline[i];
		      }
		      break;
		    case 3: /*Average*/
		      if(prevline) {
		        for(i = 0; i != bytewidth; ++i) out[i] = scanline[i] - (prevline[i] >> 1);
		        for(i = bytewidth; i < length; ++i) out[i] = scanline[i] - ((scanline[i - bytewidth] + prevline[i]) >> 1);
		      } else {
		        for(i = 0; i != bytewidth; ++i) out[i] = scanline[i];
		        for(i = bytewidth; i < length; ++i) out[i] = scanline[i] - (scanline[i - bytewidth] >> 1);
		      }
		      break;
		    case 4: /*Paeth*/
		      if(prevline) {
		        /*paethPredictor(0, prevline[i], 0) is always prevline[i]*/
		        for(i = 0; i != bytewidth; ++i) out[i] = (scanline[i] - prevline[i]);
		        for(i = bytewidth; i < length; ++i) {
		          out[i] = (scanline[i] - paethPredictor(scanline[i - bytewidth], prevline[i], prevline[i - bytewidth]));
		        }
		      } else {
		        for(i = 0; i != bytewidth; ++i) out[i] = scanline[i];
		        /*paethPredictor(scanline[i - bytewidth], 0, 0) is always scanline[i - bytewidth]*/
		        for(i = bytewidth; i < length; ++i) out[i] = (scanline[i] - scanline[i - bytewidth]);
		      }
		      break;
		    default: return; /*invalid filter type given*/
		  }
		}

		/* integer binary logarithm, max return value is 31 */
		static size_t ilog2(size_t i) {
		  size_t result = 0;
		  if(i >= 65536) { result += 16; i >>= 16; }
		  if(i >= 256) { result += 8; i >>= 8; }
		  if(i >= 16) { result += 4; i >>= 4; }
		  if(i >= 4) { result += 2; i >>= 2; }
		  if(i >= 2) { result += 1; /*i >>= 1;*/ }
		  return result;
		}

		/* integer approximation for i * log2(i), helper function for LFS_ENTROPY */
		static size_t ilog2i(size_t i) {
		  size_t l;
		  if(i == 0) return 0;
		  l = ilog2(i);
		  /* approximate i*log2(i): l is integer logarithm, ((i - (1u << l)) << 1u)
		  linearly approximates the missing fractional part multiplied by i */
		  return i * l + ((i - (1u << l)) << 1u);
		}

		static unsigned filter(uint8* out, const uint8* in, unsigned w, unsigned h,
		                       const LodePNGColorMode* color, const LodePNGEncoderSettings* settings) {
		  /*
		  For PNG filter method 0
		  out must be a buffer with as size: h + (w * h * bpp + 7u) / 8u, because there are
		  the scanlines with 1 extra byte per scanline
		  */

		  unsigned bpp = lodepng_get_bpp(color);
		  /*the width of a scanline in bytes, not including the filter type*/
		  size_t linebytes = lodepng_get_raw_size_idat(w, 1, bpp) - 1u;

		  /*bytewidth is used for filtering, is 1 when bpp < 8, number of bytes per pixel otherwise*/
		  size_t bytewidth = (bpp + 7u) / 8u;
		  const uint8* prevline = 0;
		  unsigned x, y;
		  unsigned error = 0;
		  LodePNGFilterStrategy strategy = settings.filter_strategy;

		  /*
		  There is a heuristic called the minimum sum of absolute differences heuristic, suggested by the PNG standard:
		   *  If the image type is Palette, or the bit depth is smaller than 8, then do not filter the image (i.e.
		      use fixed filtering, with the filter None).
		   * (The other case) If the image type is Grayscale or RGB (with or without Alpha), and the bit depth is
		     not smaller than 8, then use adaptive filtering heuristic as follows: independently for each row, apply
		     all five filters and select the filter that produces the smallest sum of absolute values per row.
		  This heuristic is used if filter strategy is LFS_MINSUM and filter_palette_zero is true.

		  If filter_palette_zero is true and filter_strategy is not LFS_MINSUM, the above heuristic is followed,
		  but for "the other case", whatever strategy filter_strategy is set to instead of the minimum sum
		  heuristic is used.
		  */
		  if(settings.filter_palette_zero &&
		     (color.colortype == LCT_PALETTE || color.bitdepth < 8)) strategy = LFS_ZERO;

		  if(bpp == 0) return 31; /*error: invalid color type*/

		  if(strategy >= LFS_ZERO && strategy <= LFS_FOUR) {
		    uint8 type = (uint8)strategy;
		    for(y = 0; y != h; ++y) {
		      size_t outindex = (1 + linebytes) * y; /*the extra filterbyte added to each row*/
		      size_t inindex = linebytes * y;
		      out[outindex] = type; /*filter type byte*/
		      filterScanline(&out[outindex + 1], &in[inindex], prevline, linebytes, bytewidth, type);
		      prevline = &in[inindex];
		    }
		  } else if(strategy == LFS_MINSUM) {
		    /*adaptive filtering*/
		    uint8* attempt[5]; /*five filtering attempts, one for each filter type*/
		    size_t smallest = 0;
		    uint8 type, bestType = 0;

		    for(type = 0; type != 5; ++type) {
		      attempt[type] = (uint8*)lodepng_malloc(linebytes);
		      if(!attempt[type]) error = 83; /*alloc fail*/
		    }

		    if(!error) {
		      for(y = 0; y != h; ++y) {
		        /*try the 5 filter types*/
		        for(type = 0; type != 5; ++type) {
		          size_t sum = 0;
		          filterScanline(attempt[type], &in[y * linebytes], prevline, linebytes, bytewidth, type);

		          /*calculate the sum of the result*/
		          if(type == 0) {
		            for(x = 0; x != linebytes; ++x) sum += (uint8)(attempt[type][x]);
		          } else {
		            for(x = 0; x != linebytes; ++x) {
		              /*For differences, each byte should be treated as signed, values above 127 are negative
		              (converted to signed char). Filtertype 0 isn't a difference though, so use unsigned there.
		              This means filtertype 0 is almost never chosen, but that is justified.*/
		              uint8 s = attempt[type][x];
		              sum += s < 128 ? s : (255U - s);
		            }
		          }

		          /*check if this is smallest sum (or if type == 0 it's the first case so always store the values)*/
		          if(type == 0 || sum < smallest) {
		            bestType = type;
		            smallest = sum;
		          }
		        }

		        prevline = &in[y * linebytes];

		        /*now fill the out values*/
		        out[y * (linebytes + 1)] = bestType; /*the first byte of a scanline will be the filter type*/
		        for(x = 0; x != linebytes; ++x) out[y * (linebytes + 1) + 1 + x] = attempt[bestType][x];
		      }
		    }

		    for(type = 0; type != 5; ++type) lodepng_free(attempt[type]);
		  } else if(strategy == LFS_ENTROPY) {
		    uint8* attempt[5]; /*five filtering attempts, one for each filter type*/
		    size_t bestSum = 0;
		    unsigned type, bestType = 0;
		    unsigned count[256];

		    for(type = 0; type != 5; ++type) {
		      attempt[type] = (uint8*)lodepng_malloc(linebytes);
		      if(!attempt[type]) error = 83; /*alloc fail*/
		    }

		    if(!error) {
		      for(y = 0; y != h; ++y) {
		        /*try the 5 filter types*/
		        for(type = 0; type != 5; ++type) {
		          size_t sum = 0;
		          filterScanline(attempt[type], &in[y * linebytes], prevline, linebytes, bytewidth, type);
		          lodepng_memset(count, 0, 256 * sizeof(*count));
		          for(x = 0; x != linebytes; ++x) ++count[attempt[type][x]];
		          ++count[type]; /*the filter type itself is part of the scanline*/
		          for(x = 0; x != 256; ++x) {
		            sum += ilog2i(count[x]);
		          }
		          /*check if this is smallest sum (or if type == 0 it's the first case so always store the values)*/
		          if(type == 0 || sum > bestSum) {
		            bestType = type;
		            bestSum = sum;
		          }
		        }

		        prevline = &in[y * linebytes];

		        /*now fill the out values*/
		        out[y * (linebytes + 1)] = bestType; /*the first byte of a scanline will be the filter type*/
		        for(x = 0; x != linebytes; ++x) out[y * (linebytes + 1) + 1 + x] = attempt[bestType][x];
		      }
		    }

		    for(type = 0; type != 5; ++type) lodepng_free(attempt[type]);
		  } else if(strategy == LFS_PREDEFINED) {
		    for(y = 0; y != h; ++y) {
		      size_t outindex = (1 + linebytes) * y; /*the extra filterbyte added to each row*/
		      size_t inindex = linebytes * y;
		      uint8 type = settings.predefined_filters[y];
		      out[outindex] = type; /*filter type byte*/
		      filterScanline(&out[outindex + 1], &in[inindex], prevline, linebytes, bytewidth, type);
		      prevline = &in[inindex];
		    }
		  } else if(strategy == LFS_BRUTE_FORCE) {
		    /*brute force filter chooser.
		    deflate the scanline after every filter attempt to see which one deflates best.
		    This is very slow and gives only slightly smaller, sometimes even larger, result*/
		    size_t size[5];
		    uint8* attempt[5]; /*five filtering attempts, one for each filter type*/
		    size_t smallest = 0;
		    unsigned type = 0, bestType = 0;
		    uint8* dummy;
		    LodePNGCompressSettings zlibsettings;
		    lodepng_memcpy(&zlibsettings, &settings.zlibsettings, sizeof(LodePNGCompressSettings));
		    /*use fixed tree on the attempts so that the tree is not adapted to the filtertype on purpose,
		    to simulate the true case where the tree is the same for the whole image. Sometimes it gives
		    better result with dynamic tree anyway. Using the fixed tree sometimes gives worse, but in rare
		    cases better compression. It does make this a bit less slow, so it's worth doing this.*/
		    zlibsettings.btype = 1;
		    /*a custom encoder likely doesn't read the btype setting and is optimized for complete PNG
		    images only, so disable it*/
		    zlibsettings.custom_zlib = 0;
		    zlibsettings.custom_deflate = 0;
		    for(type = 0; type != 5; ++type) {
		      attempt[type] = (uint8*)lodepng_malloc(linebytes);
		      if(!attempt[type]) error = 83; /*alloc fail*/
		    }
		    if(!error) {
		      for(y = 0; y != h; ++y) /*try the 5 filter types*/ {
		        for(type = 0; type != 5; ++type) {
		          unsigned testsize = (unsigned)linebytes;
		          /*if(testsize > 8) testsize /= 8;*/ /*it already works good enough by testing a part of the row*/

		          filterScanline(attempt[type], &in[y * linebytes], prevline, linebytes, bytewidth, type);
		          size[type] = 0;
		          dummy = 0;
		          zlib_compress(&dummy, &size[type], attempt[type], testsize, &zlibsettings);
		          lodepng_free(dummy);
		          /*check if this is smallest size (or if type == 0 it's the first case so always store the values)*/
		          if(type == 0 || size[type] < smallest) {
		            bestType = type;
		            smallest = size[type];
		          }
		        }
		        prevline = &in[y * linebytes];
		        out[y * (linebytes + 1)] = bestType; /*the first byte of a scanline will be the filter type*/
		        for(x = 0; x != linebytes; ++x) out[y * (linebytes + 1) + 1 + x] = attempt[bestType][x];
		      }
		    }
		    for(type = 0; type != 5; ++type) lodepng_free(attempt[type]);
		  }
		  else return 88; /* unknown filter strategy */

		  return error;
		}

		static void addPaddingBits(uint8* out, const uint8* in,
		                           size_t olinebits, size_t ilinebits, unsigned h) {
		  /*The opposite of the removePaddingBits function
		  olinebits must be >= ilinebits*/
		  unsigned y;
		  size_t diff = olinebits - ilinebits;
		  size_t obp = 0, ibp = 0; /*bit pointers*/
		  for(y = 0; y != h; ++y) {
		    size_t x;
		    for(x = 0; x < ilinebits; ++x) {
		      uint8 bit = readBitFromReversedStream(&ibp, in);
		      setBitOfReversedStream(&obp, out, bit);
		    }
		    /*obp += diff; -. no, fill in some value in the padding bits too, to avoid
		    "Use of uninitialised value of size ###" warning from valgrind*/
		    for(x = 0; x != diff; ++x) setBitOfReversedStream(&obp, out, 0);
		  }
		}

		/*
		in: non-interlaced image with size w*h
		out: the same pixels, but re-ordered according to PNG's Adam7 interlacing, with
		 no padding bits between scanlines, but between reduced images so that each
		 reduced image starts at a byte.
		bpp: bits per pixel
		there are no padding bits, not between scanlines, not between reduced images
		in has the following size in bits: w * h * bpp.
		out is possibly bigger due to padding bits between reduced images
		NOTE: comments about padding bits are only relevant if bpp < 8
		*/
		static void Adam7_interlace(uint8* out, const uint8* in, unsigned w, unsigned h, unsigned bpp) {
		  unsigned passw[7], passh[7];
		  size_t filter_passstart[8], padded_passstart[8], passstart[8];
		  unsigned i;

		  Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp);

		  if(bpp >= 8) {
		    for(i = 0; i != 7; ++i) {
		      unsigned x, y, b;
		      size_t bytewidth = bpp / 8u;
		      for(y = 0; y < passh[i]; ++y)
		      for(x = 0; x < passw[i]; ++x) {
		        size_t pixelinstart = ((ADAM7_IY[i] + y * ADAM7_DY[i]) * w + ADAM7_IX[i] + x * ADAM7_DX[i]) * bytewidth;
		        size_t pixeloutstart = passstart[i] + (y * passw[i] + x) * bytewidth;
		        for(b = 0; b < bytewidth; ++b) {
		          out[pixeloutstart + b] = in[pixelinstart + b];
		        }
		      }
		    }
		  } else /*bpp < 8: Adam7 with pixels < 8 bit is a bit trickier: with bit pointers*/ {
		    for(i = 0; i != 7; ++i) {
		      unsigned x, y, b;
		      unsigned ilinebits = bpp * passw[i];
		      unsigned olinebits = bpp * w;
		      size_t obp, ibp; /*bit pointers (for out and in buffer)*/
		      for(y = 0; y < passh[i]; ++y)
		      for(x = 0; x < passw[i]; ++x) {
		        ibp = (ADAM7_IY[i] + y * ADAM7_DY[i]) * olinebits + (ADAM7_IX[i] + x * ADAM7_DX[i]) * bpp;
		        obp = (8 * passstart[i]) + (y * ilinebits + x * bpp);
		        for(b = 0; b < bpp; ++b) {
		          uint8 bit = readBitFromReversedStream(&ibp, in);
		          setBitOfReversedStream(&obp, out, bit);
		        }
		      }
		    }
		  }
		}

		/*out must be buffer big enough to contain uncompressed IDAT chunk data, and in must contain the full image.
		return value is error**/
		static unsigned preProcessScanlines(uint8** out, size_t* outsize, const uint8* in,
		                                    unsigned w, unsigned h,
		                                    const LodePNGInfo* info_png, const LodePNGEncoderSettings* settings) {
		  /*
		  This function converts the pure 2D image with the PNG's colortype, into filtered-padded-interlaced data. Steps:
		  *) if no Adam7: 1) add padding bits (= possible extra bits per scanline if bpp < 8) 2) filter
		  *) if adam7: 1) Adam7_interlace 2) 7x add padding bits 3) 7x filter
		  */
		  unsigned bpp = lodepng_get_bpp(&info_png.color);
		  unsigned error = 0;

		  if(info_png.interlace_method == 0) {
		    *outsize = h + (h * ((w * bpp + 7u) / 8u)); /*image size plus an extra byte per scanline + possible padding bits*/
		    *out = (uint8*)lodepng_malloc(*outsize);
		    if(!(*out) && (*outsize)) error = 83; /*alloc fail*/

		    if(!error) {
		      /*non multiple of 8 bits per scanline, padding bits needed per scanline*/
		      if(bpp < 8 && w * bpp != ((w * bpp + 7u) / 8u) * 8u) {
		        uint8* padded = (uint8*)lodepng_malloc(h * ((w * bpp + 7u) / 8u));
		        if(!padded) error = 83; /*alloc fail*/
		        if(!error) {
		          addPaddingBits(padded, in, ((w * bpp + 7u) / 8u) * 8u, w * bpp, h);
		          error = filter(*out, padded, w, h, &info_png.color, settings);
		        }
		        lodepng_free(padded);
		      } else {
		        /*we can immediately filter into the out buffer, no other steps needed*/
		        error = filter(*out, in, w, h, &info_png.color, settings);
		      }
		    }
		  } else /*interlace_method is 1 (Adam7)*/ {
		    unsigned passw[7], passh[7];
		    size_t filter_passstart[8], padded_passstart[8], passstart[8];
		    uint8* adam7;

		    Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp);

		    *outsize = filter_passstart[7]; /*image size plus an extra byte per scanline + possible padding bits*/
		    *out = (uint8*)lodepng_malloc(*outsize);
		    if(!(*out)) error = 83; /*alloc fail*/

		    adam7 = (uint8*)lodepng_malloc(passstart[7]);
		    if(!adam7 && passstart[7]) error = 83; /*alloc fail*/

		    if(!error) {
		      unsigned i;

		      Adam7_interlace(adam7, in, w, h, bpp);
		      for(i = 0; i != 7; ++i) {
		        if(bpp < 8) {
		          uint8* padded = (uint8*)lodepng_malloc(padded_passstart[i + 1] - padded_passstart[i]);
		          if(!padded) CERROR_BREAK!(error, 83); /*alloc fail*/
		          addPaddingBits(padded, &adam7[passstart[i]],
		                         ((passw[i] * bpp + 7u) / 8u) * 8u, passw[i] * bpp, passh[i]);
		          error = filter(&(*out)[filter_passstart[i]], padded,
		                         passw[i], passh[i], &info_png.color, settings);
		          lodepng_free(padded);
		        } else {
		          error = filter(&(*out)[filter_passstart[i]], &adam7[padded_passstart[i]],
		                         passw[i], passh[i], &info_png.color, settings);
		        }

		        if(error) break;
		      }
		    }

		    lodepng_free(adam7);
		  }

		  return error;
		}

#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		static unsigned addUnknownChunks(ucvector* out, uint8* data, size_t datasize) {
		  uint8* inchunk = data;
		  while((size_t)(inchunk - data) < datasize) {
		    CERROR_TRY_RETURN(lodepng_chunk_append(&out.data, &out.size, inchunk));
		    out.allocsize = out.size; /*fix the allocsize again*/
		    inchunk = lodepng_chunk_next(inchunk, data + datasize);
		  }
		  return 0;
		}

		static unsigned isGrayICCProfile(const uint8* profile, unsigned size) {
		  /*
		  It is a gray profile if bytes 16-19 are "GRAY", rgb profile if bytes 16-19
		  are "RGB ". We do not perform any full parsing of the ICC profile here, other
		  than check those 4 bytes to grayscale profile. Other than that, validity of
		  the profile is not checked. This is needed only because the PNG specification
		  requires using a non-gray color model if there is an ICC profile with "RGB "
		  (sadly limiting compression opportunities if the input data is grayscale RGB
		  data), and requires using a gray color model if it is "GRAY".
		  */
		  if(size < 20) return 0;
		  return profile[16] == 'G' &&  profile[17] == 'R' &&  profile[18] == 'A' &&  profile[19] == 'Y';
		}

		static unsigned isRGBICCProfile(const uint8* profile, unsigned size) {
		  /* See comment in isGrayICCProfile*/
		  if(size < 20) return 0;
		  return profile[16] == 'R' &&  profile[17] == 'G' &&  profile[18] == 'B' &&  profile[19] == ' ';
		}
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/

		unsigned lodepng_encode(uint8** out, size_t* outsize,
		                        const uint8* image, unsigned w, unsigned h,
		                        LodePNGState* state) {
		  uint8* data = 0; /*uncompressed version of the IDAT chunk data*/
		  size_t datasize = 0;
		  ucvector outv = ucvector_init(NULL, 0);
		  LodePNGInfo info;
		  const LodePNGInfo* info_png = &state.info_png;

		  lodepng_info_init(&info);

		  /*provide some proper output values if error will happen*/
		  *out = 0;
		  *outsize = 0;
		  state.error = 0;

		  /*check input values validity*/
		  if((info_png.color.colortype == LCT_PALETTE || state.encoder.force_palette)
		      && (info_png.color.palettesize == 0 || info_png.color.palettesize > 256)) {
		    state.error = 68; /*invalid palette size, it is only allowed to be 1-256*/
		    goto cleanup;
		  }
		  if(state.encoder.zlibsettings.btype > 2) {
		    state.error = 61; /*error: invalid btype*/
		    goto cleanup;
		  }
		  if(info_png.interlace_method > 1) {
		    state.error = 71; /*error: invalid interlace mode*/
		    goto cleanup;
		  }
		  state.error = checkColorValidity(info_png.color.colortype, info_png.color.bitdepth);
		  if(state.error) goto cleanup; /*error: invalid color type given*/
		  state.error = checkColorValidity(state.info_raw.colortype, state.info_raw.bitdepth);
		  if(state.error) goto cleanup; /*error: invalid color type given*/

		  /* color convert and compute scanline filter types */
		  lodepng_info_copy(&info, &state.info_png);
		  if(state.encoder.auto_convert) {
		    LodePNGColorStats stats;
		    lodepng_color_stats_init(&stats);
#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		    if(info_png.iccp_defined &&
		        isGrayICCProfile(info_png.iccp_profile, info_png.iccp_profile_size)) {
		      /*the PNG specification does not allow to use palette with a GRAY ICC profile, even
		      if the palette has only gray colors, so disallow it.*/
		      stats.allow_palette = 0;
		    }
		    if(info_png.iccp_defined &&
		        isRGBICCProfile(info_png.iccp_profile, info_png.iccp_profile_size)) {
		      /*the PNG specification does not allow to use grayscale color with RGB ICC profile, so disallow gray.*/
		      stats.allow_greyscale = 0;
		    }
#endif /* LODEPNG_COMPILE_ANCILLARY_CHUNKS */
		    state.error = lodepng_compute_color_stats(&stats, image, w, h, &state.info_raw);
		    if(state.error) goto cleanup;
#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		    if(info_png.background_defined) {
		      /*the background chunk's color must be taken into account as well*/
		      unsigned r = 0, g = 0, b = 0;
		      LodePNGColorMode mode16 = lodepng_color_mode_make(LCT_RGB, 16);
		      lodepng_convert_rgb(&r, &g, &b, info_png.background_r, info_png.background_g, info_png.background_b, &mode16, &info_png.color);
		      state.error = lodepng_color_stats_add(&stats, r, g, b, 65535);
		      if(state.error) goto cleanup;
		    }
#endif /* LODEPNG_COMPILE_ANCILLARY_CHUNKS */
		    state.error = auto_choose_color(&info.color, &state.info_raw, &stats);
		    if(state.error) goto cleanup;
#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		    /*also convert the background chunk*/
		    if(info_png.background_defined) {
		      if(lodepng_convert_rgb(&info.background_r, &info.background_g, &info.background_b,
		          info_png.background_r, info_png.background_g, info_png.background_b, &info.color, &info_png.color)) {
		        state.error = 104;
		        goto cleanup;
		      }
		    }
#endif /* LODEPNG_COMPILE_ANCILLARY_CHUNKS */
		  }
#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		  if(info_png.iccp_defined) {
		    unsigned gray_icc = isGrayICCProfile(info_png.iccp_profile, info_png.iccp_profile_size);
		    unsigned rgb_icc = isRGBICCProfile(info_png.iccp_profile, info_png.iccp_profile_size);
		    unsigned gray_png = info.color.colortype == LCT_GREY || info.color.colortype == LCT_GREY_ALPHA;
		    if(!gray_icc && !rgb_icc) {
		      state.error = 100; /* Disallowed profile color type for PNG */
		      goto cleanup;
		    }
		    if(gray_icc != gray_png) {
		      /*Not allowed to use RGB/RGBA/palette with GRAY ICC profile or vice versa,
		      or in case of auto_convert, it wasn't possible to find appropriate model*/
		      state.error = state.encoder.auto_convert ? 102 : 101;
		      goto cleanup;
		    }
		  }
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
		  if(!lodepng_color_mode_equal(&state.info_raw, &info.color)) {
		    uint8* converted;
		    size_t size = ((size_t)w * (size_t)h * (size_t)lodepng_get_bpp(&info.color) + 7u) / 8u;

		    converted = (uint8*)lodepng_malloc(size);
		    if(!converted && size) state.error = 83; /*alloc fail*/
		    if(!state.error) {
		      state.error = lodepng_convert(converted, image, &info.color, &state.info_raw, w, h);
		    }
		    if(!state.error) {
		      state.error = preProcessScanlines(&data, &datasize, converted, w, h, &info, &state.encoder);
		    }
		    lodepng_free(converted);
		    if(state.error) goto cleanup;
		  } else {
		    state.error = preProcessScanlines(&data, &datasize, image, w, h, &info, &state.encoder);
		    if(state.error) goto cleanup;
		  }

		  /* output all PNG chunks */ {
#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		    size_t i;
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
		    /*write signature and chunks*/
		    state.error = writeSignature(&outv);
		    if(state.error) goto cleanup;
		    /*IHDR*/
		    state.error = addChunk_IHDR(&outv, w, h, info.color.colortype, info.color.bitdepth, info.interlace_method);
		    if(state.error) goto cleanup;
#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		    /*unknown chunks between IHDR and PLTE*/
		    if(info.unknown_chunks_data[0]) {
		      state.error = addUnknownChunks(&outv, info.unknown_chunks_data[0], info.unknown_chunks_size[0]);
		      if(state.error) goto cleanup;
		    }
		    /*color profile chunks must come before PLTE */
		    if(info.iccp_defined) {
		      state.error = addChunk_iCCP(&outv, &info, &state.encoder.zlibsettings);
		      if(state.error) goto cleanup;
		    }
		    if(info.srgb_defined) {
		      state.error = addChunk_sRGB(&outv, &info);
		      if(state.error) goto cleanup;
		    }
		    if(info.gama_defined) {
		      state.error = addChunk_gAMA(&outv, &info);
		      if(state.error) goto cleanup;
		    }
		    if(info.chrm_defined) {
		      state.error = addChunk_cHRM(&outv, &info);
		      if(state.error) goto cleanup;
		    }
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
		    /*PLTE*/
		    if(info.color.colortype == LCT_PALETTE) {
		      state.error = addChunk_PLTE(&outv, &info.color);
		      if(state.error) goto cleanup;
		    }
		    if(state.encoder.force_palette && (info.color.colortype == LCT_RGB || info.color.colortype == LCT_RGBA)) {
		      /*force_palette means: write suggested palette for truecolor in PLTE chunk*/
		      state.error = addChunk_PLTE(&outv, &info.color);
		      if(state.error) goto cleanup;
		    }
		    /*tRNS (this will only add if when necessary) */
		    state.error = addChunk_tRNS(&outv, &info.color);
		    if(state.error) goto cleanup;
#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		    /*bKGD (must come between PLTE and the IDAt chunks*/
		    if(info.background_defined) {
		      state.error = addChunk_bKGD(&outv, &info);
		      if(state.error) goto cleanup;
		    }
		    /*pHYs (must come before the IDAT chunks)*/
		    if(info.phys_defined) {
		      state.error = addChunk_pHYs(&outv, &info);
		      if(state.error) goto cleanup;
		    }

		    /*unknown chunks between PLTE and IDAT*/
		    if(info.unknown_chunks_data[1]) {
		      state.error = addUnknownChunks(&outv, info.unknown_chunks_data[1], info.unknown_chunks_size[1]);
		      if(state.error) goto cleanup;
		    }
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
		    /*IDAT (multiple IDAT chunks must be consecutive)*/
		    state.error = addChunk_IDAT(&outv, data, datasize, &state.encoder.zlibsettings);
		    if(state.error) goto cleanup;
#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		    /*tIME*/
		    if(info.time_defined) {
		      state.error = addChunk_tIME(&outv, &info.time);
		      if(state.error) goto cleanup;
		    }
		    /*tEXt and/or zTXt*/
		    for(i = 0; i != info.text_num; ++i) {
		      if(lodepng_strlen(info.text_keys[i]) > 79) {
		        state.error = 66; /*text chunk too large*/
		        goto cleanup;
		      }
		      if(lodepng_strlen(info.text_keys[i]) < 1) {
		        state.error = 67; /*text chunk too small*/
		        goto cleanup;
		      }
		      if(state.encoder.text_compression) {
		        state.error = addChunk_zTXt(&outv, info.text_keys[i], info.text_strings[i], &state.encoder.zlibsettings);
		        if(state.error) goto cleanup;
		      } else {
		        state.error = addChunk_tEXt(&outv, info.text_keys[i], info.text_strings[i]);
		        if(state.error) goto cleanup;
		      }
		    }
		    /*LodePNG version id in text chunk*/
		    if(state.encoder.add_id) {
		      unsigned already_added_id_text = 0;
		      for(i = 0; i != info.text_num; ++i) {
		        const char* k = info.text_keys[i];
		        /* Could use strcmp, but we're not calling or reimplementing this C library function for this use only */
		        if(k[0] == 'L' && k[1] == 'o' && k[2] == 'd' && k[3] == 'e' &&
		           k[4] == 'P' && k[5] == 'N' && k[6] == 'G' && k[7] == '\0') {
		          already_added_id_text = 1;
		          break;
		        }
		      }
		      if(already_added_id_text == 0) {
		        state.error = addChunk_tEXt(&outv, "LodePNG", LODEPNG_VERSION_STRING); /*it's shorter as tEXt than as zTXt chunk*/
		        if(state.error) goto cleanup;
		      }
		    }
		    /*iTXt*/
		    for(i = 0; i != info.itext_num; ++i) {
		      if(lodepng_strlen(info.itext_keys[i]) > 79) {
		        state.error = 66; /*text chunk too large*/
		        goto cleanup;
		      }
		      if(lodepng_strlen(info.itext_keys[i]) < 1) {
		        state.error = 67; /*text chunk too small*/
		        goto cleanup;
		      }
		      state.error = addChunk_iTXt(
		          &outv, state.encoder.text_compression,
		          info.itext_keys[i], info.itext_langtags[i], info.itext_transkeys[i], info.itext_strings[i],
		          &state.encoder.zlibsettings);
		      if(state.error) goto cleanup;
		    }

		    /*unknown chunks between IDAT and IEND*/
		    if(info.unknown_chunks_data[2]) {
		      state.error = addUnknownChunks(&outv, info.unknown_chunks_data[2], info.unknown_chunks_size[2]);
		      if(state.error) goto cleanup;
		    }
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
		    state.error = addChunk_IEND(&outv);
		    if(state.error) goto cleanup;
		  }

		cleanup:
		  lodepng_info_cleanup(&info);
		  lodepng_free(data);

		  /*instead of cleaning the vector up, give it to the output*/
		  *out = outv.data;
		  *outsize = outv.size;

		  return state.error;
		}

		unsigned lodepng_encode_memory(uint8** out, size_t* outsize, const uint8* image,
		                               unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth) {
		  unsigned error;
		  LodePNGState state;
		  lodepng_state_init(&state);
		  state.info_raw.colortype = colortype;
		  state.info_raw.bitdepth = bitdepth;
		  state.info_png.color.colortype = colortype;
		  state.info_png.color.bitdepth = bitdepth;
		  lodepng_encode(out, outsize, image, w, h, &state);
		  error = state.error;
		  lodepng_state_cleanup(&state);
		  return error;
		}

		unsigned lodepng_encode32(uint8** out, size_t* outsize, const uint8* image, unsigned w, unsigned h) {
		  return lodepng_encode_memory(out, outsize, image, w, h, LCT_RGBA, 8);
		}

		unsigned lodepng_encode24(uint8** out, size_t* outsize, const uint8* image, unsigned w, unsigned h) {
		  return lodepng_encode_memory(out, outsize, image, w, h, LCT_RGB, 8);
		}

#if LODEPNG_COMPILE_DISK
		unsigned lodepng_encode_file(const char* filename, const uint8* image, unsigned w, unsigned h,
		                             LodePNGColorType colortype, unsigned bitdepth) {
		  uint8* buffer;
		  size_t buffersize;
		  unsigned error = lodepng_encode_memory(&buffer, &buffersize, image, w, h, colortype, bitdepth);
		  if(!error) error = lodepng_save_file(buffer, buffersize, filename);
		  lodepng_free(buffer);
		  return error;
		}

		unsigned lodepng_encode32_file(const char* filename, const uint8* image, unsigned w, unsigned h) {
		  return lodepng_encode_file(filename, image, w, h, LCT_RGBA, 8);
		}

		unsigned lodepng_encode24_file(const char* filename, const uint8* image, unsigned w, unsigned h) {
		  return lodepng_encode_file(filename, image, w, h, LCT_RGB, 8);
		}
#endif /*LODEPNG_COMPILE_DISK*/

		void lodepng_encoder_settings_init(LodePNGEncoderSettings* settings) {
		  lodepng_compress_settings_init(&settings.zlibsettings);
		  settings.filter_palette_zero = 1;
		  settings.filter_strategy = LFS_MINSUM;
		  settings.auto_convert = 1;
		  settings.force_palette = 0;
		  settings.predefined_filters = 0;
#if LODEPNG_COMPILE_ANCILLARY_CHUNKS
		  settings.add_id = 0;
		  settings.text_compression = 1;
#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
		}

#endif /*LODEPNG_COMPILE_ENCODER*/
#endif /*LODEPNG_COMPILE_PNG*/

#if LODEPNG_COMPILE_ERROR_TEXT
		/*
		This returns the description of a numerical error code in English. This is also
		the documentation of all the error codes.
		*/
		const char* lodepng_error_text(unsigned code) {
		  switch(code) {
		    case 0: return "no error, everything went ok";
		    case 1: return "nothing done yet"; /*the Encoder/Decoder has done nothing yet, error checking makes no sense yet*/
		    case 10: return "end of input memory reached without huffman end code"; /*while huffman decoding*/
		    case 11: return "error in code tree made it jump outside of huffman tree"; /*while huffman decoding*/
		    case 13: return "problem while processing dynamic deflate block";
		    case 14: return "problem while processing dynamic deflate block";
		    case 15: return "problem while processing dynamic deflate block";
		    /*this error could happen if there are only 0 or 1 symbols present in the huffman code:*/
		    case 16: return "invalid code while processing dynamic deflate block";
		    case 17: return "end of out buffer memory reached while inflating";
		    case 18: return "invalid distance code while inflating";
		    case 19: return "end of out buffer memory reached while inflating";
		    case 20: return "invalid deflate block BTYPE encountered while decoding";
		    case 21: return "NLEN is not ones complement of LEN in a deflate block";

		    /*end of out buffer memory reached while inflating:
		    This can happen if the inflated deflate data is longer than the amount of bytes required to fill up
		    all the pixels of the image, given the color depth and image dimensions. Something that doesn't
		    happen in a normal, well encoded, PNG image.*/
		    case 22: return "end of out buffer memory reached while inflating";
		    case 23: return "end of in buffer memory reached while inflating";
		    case 24: return "invalid FCHECK in zlib header";
		    case 25: return "invalid compression method in zlib header";
		    case 26: return "FDICT encountered in zlib header while it's not used for PNG";
		    case 27: return "PNG file is smaller than a PNG header";
		    /*Checks the magic file header, the first 8 bytes of the PNG file*/
		    case 28: return "incorrect PNG signature, it's no PNG or corrupted";
		    case 29: return "first chunk is not the header chunk";
		    case 30: return "chunk length too large, chunk broken off at end of file";
		    case 31: return "illegal PNG color type or bpp";
		    case 32: return "illegal PNG compression method";
		    case 33: return "illegal PNG filter method";
		    case 34: return "illegal PNG interlace method";
		    case 35: return "chunk length of a chunk is too large or the chunk too small";
		    case 36: return "illegal PNG filter type encountered";
		    case 37: return "illegal bit depth for this color type given";
		    case 38: return "the palette is too small or too big"; /*0, or more than 256 colors*/
		    case 39: return "tRNS chunk before PLTE or has more entries than palette size";
		    case 40: return "tRNS chunk has wrong size for grayscale image";
		    case 41: return "tRNS chunk has wrong size for RGB image";
		    case 42: return "tRNS chunk appeared while it was not allowed for this color type";
		    case 43: return "bKGD chunk has wrong size for palette image";
		    case 44: return "bKGD chunk has wrong size for grayscale image";
		    case 45: return "bKGD chunk has wrong size for RGB image";
		    case 48: return "empty input buffer given to decoder. Maybe caused by non-existing file?";
		    case 49: return "jumped past memory while generating dynamic huffman tree";
		    case 50: return "jumped past memory while generating dynamic huffman tree";
		    case 51: return "jumped past memory while inflating huffman block";
		    case 52: return "jumped past memory while inflating";
		    case 53: return "size of zlib data too small";
		    case 54: return "repeat symbol in tree while there was no value symbol yet";
		    /*jumped past tree while generating huffman tree, this could be when the
		    tree will have more leaves than symbols after generating it out of the
		    given lengths. They call this an oversubscribed dynamic bit lengths tree in zlib.*/
		    case 55: return "jumped past tree while generating huffman tree";
		    case 56: return "given output image colortype or bitdepth not supported for color conversion";
		    case 57: return "invalid CRC encountered (checking CRC can be disabled)";
		    case 58: return "invalid ADLER32 encountered (checking ADLER32 can be disabled)";
		    case 59: return "requested color conversion not supported";
		    case 60: return "invalid window size given in the settings of the encoder (must be 0-32768)";
		    case 61: return "invalid BTYPE given in the settings of the encoder (only 0, 1 and 2 are allowed)";
		    /*LodePNG leaves the choice of RGB to grayscale conversion formula to the user.*/
		    case 62: return "conversion from color to grayscale not supported";
		    /*(2^31-1)*/
		    case 63: return "length of a chunk too long, max allowed for PNG is 2147483647 bytes per chunk";
		    /*this would result in the inability of a deflated block to ever contain an end code. It must be at least 1.*/
		    case 64: return "the length of the END symbol 256 in the Huffman tree is 0";
		    case 66: return "the length of a text chunk keyword given to the encoder is longer than the maximum of 79 bytes";
		    case 67: return "the length of a text chunk keyword given to the encoder is smaller than the minimum of 1 byte";
		    case 68: return "tried to encode a PLTE chunk with a palette that has less than 1 or more than 256 colors";
		    case 69: return "unknown chunk type with 'critical' flag encountered by the decoder";
		    case 71: return "invalid interlace mode given to encoder (must be 0 or 1)";
		    case 72: return "while decoding, invalid compression method encountering in zTXt or iTXt chunk (it must be 0)";
		    case 73: return "invalid tIME chunk size";
		    case 74: return "invalid pHYs chunk size";
		    /*length could be wrong, or data chopped off*/
		    case 75: return "no null termination char found while decoding text chunk";
		    case 76: return "iTXt chunk too short to contain required bytes";
		    case 77: return "integer overflow in buffer size";
		    case 78: return "failed to open file for reading"; /*file doesn't exist or couldn't be opened for reading*/
		    case 79: return "failed to open file for writing";
		    case 80: return "tried creating a tree of 0 symbols";
		    case 81: return "lazy matching at pos 0 is impossible";
		    case 82: return "color conversion to palette requested while a color isn't in palette, or index out of bounds";
		    case 83: return "memory allocation failed";
		    case 84: return "given image too small to contain all pixels to be encoded";
		    case 86: return "impossible offset in lz77 encoding (internal bug)";
		    case 87: return "must provide custom zlib function pointer if LODEPNG_COMPILE_ZLIB is not defined";
		    case 88: return "invalid filter strategy given for LodePNGEncoderSettings.filter_strategy";
		    case 89: return "text chunk keyword too short or long: must have size 1-79";
		    /*the windowsize in the LodePNGCompressSettings. Requiring POT(==> & instead of %) makes encoding 12% faster.*/
		    case 90: return "windowsize must be a power of two";
		    case 91: return "invalid decompressed idat size";
		    case 92: return "integer overflow due to too many pixels";
		    case 93: return "zero width or height is invalid";
		    case 94: return "header chunk must have a size of 13 bytes";
		    case 95: return "integer overflow with combined idat chunk size";
		    case 96: return "invalid gAMA chunk size";
		    case 97: return "invalid cHRM chunk size";
		    case 98: return "invalid sRGB chunk size";
		    case 99: return "invalid sRGB rendering intent";
		    case 100: return "invalid ICC profile color type, the PNG specification only allows RGB or GRAY";
		    case 101: return "PNG specification does not allow RGB ICC profile on gray color types and vice versa";
		    case 102: return "not allowed to set grayscale ICC profile with colored pixels by PNG specification";
		    case 103: return "invalid palette index in bKGD chunk. Maybe it came before PLTE chunk?";
		    case 104: return "invalid bKGD color while encoding (e.g. palette index out of range)";
		    case 105: return "integer overflow of bitsize";
		    case 106: return "PNG file must have PLTE chunk if color type is palette";
		    case 107: return "color convert from palette mode requested without setting the palette data in it";
		    case 108: return "tried to add more than 256 values to a palette";
		    /*this limit can be configured in LodePNGDecompressSettings*/
		    case 109: return "tried to decompress zlib or deflate data larger than desired max_output_size";
		    case 110: return "custom zlib or inflate decompression failed";
		    case 111: return "custom zlib or deflate compression failed";
		    /*max text size limit can be configured in LodePNGDecoderSettings. This error prevents
		    unreasonable memory consumption when decoding due to impossibly large text sizes.*/
		    case 112: return "compressed text unreasonably large";
		    /*max ICC size limit can be configured in LodePNGDecoderSettings. This error prevents
		    unreasonable memory consumption when decoding due to impossibly large ICC profile*/
		    case 113: return "ICC profile unreasonably large";
		  }
		  return "unknown error code";
		}
#endif /*LODEPNG_COMPILE_ERROR_TEXT*/

		/* ////////////////////////////////////////////////////////////////////////// */
		/* ////////////////////////////////////////////////////////////////////////// */
		/* // C++ Wrapper                                                          // */
		/* ////////////////////////////////////////////////////////////////////////// */
		/* ////////////////////////////////////////////////////////////////////////// */

#if LODEPNG_COMPILE_CPP
		namespace lodepng {

#if LODEPNG_COMPILE_DISK
		unsigned load_file(std::vector<uint8>& buffer, const std::string& filename) {
		  long size = lodepng_filesize(filename.c_str());
		  if(size < 0) return 78;
		  buffer.resize((size_t)size);
		  return size == 0 ? 0 : lodepng_buffer_file(&buffer[0], (size_t)size, filename.c_str());
		}

		/*write given buffer to the file, overwriting the file, it doesn't append to it.*/
		unsigned save_file(const std::vector<uint8>& buffer, const std::string& filename) {
		  return lodepng_save_file(buffer.empty() ? 0 : &buffer[0], buffer.size(), filename.c_str());
		}
#endif /* LODEPNG_COMPILE_DISK */

#if LODEPNG_COMPILE_ZLIB
#if LODEPNG_COMPILE_DECODER
		unsigned decompress(std::vector<uint8>& out, const uint8* in, size_t insize,
		                    const LodePNGDecompressSettings& settings) {
		  uint8* buffer = 0;
		  size_t buffersize = 0;
		  unsigned error = zlib_decompress(&buffer, &buffersize, 0, in, insize, &settings);
		  if(buffer) {
		    out.insert(out.end(), &buffer[0], &buffer[buffersize]);
		    lodepng_free(buffer);
		  }
		  return error;
		}

		unsigned decompress(std::vector<uint8>& out, const std::vector<uint8>& in,
		                    const LodePNGDecompressSettings& settings) {
		  return decompress(out, in.empty() ? 0 : &in[0], in.size(), settings);
		}
#endif /* LODEPNG_COMPILE_DECODER */

#if LODEPNG_COMPILE_ENCODER
		unsigned compress(std::vector<uint8>& out, const uint8* in, size_t insize,
		                  const LodePNGCompressSettings& settings) {
		  uint8* buffer = 0;
		  size_t buffersize = 0;
		  unsigned error = zlib_compress(&buffer, &buffersize, in, insize, &settings);
		  if(buffer) {
		    out.insert(out.end(), &buffer[0], &buffer[buffersize]);
		    lodepng_free(buffer);
		  }
		  return error;
		}

		unsigned compress(std::vector<uint8>& out, const std::vector<uint8>& in,
		                  const LodePNGCompressSettings& settings) {
		  return compress(out, in.empty() ? 0 : &in[0], in.size(), settings);
		}
#endif /* LODEPNG_COMPILE_ENCODER */
#endif /* LODEPNG_COMPILE_ZLIB */


#if LODEPNG_COMPILE_PNG

		State::State() {
		  lodepng_state_init(this);
		}

		State::State(const State& other) {
		  lodepng_state_init(this);
		  lodepng_state_copy(this, &other);
		}

		State::~State() {
		  lodepng_state_cleanup(this);
		}

		State& State::operator=(const State& other) {
		  lodepng_state_copy(this, &other);
		  return *this;
		}

#if LODEPNG_COMPILE_DECODER

		unsigned decode(std::vector<uint8>& out, unsigned& w, unsigned& h, const uint8* in,
		                size_t insize, LodePNGColorType colortype, unsigned bitdepth) {
		  uint8* buffer = 0;
		  unsigned error = lodepng_decode_memory(&buffer, &w, &h, in, insize, colortype, bitdepth);
		  if(buffer && !error) {
		    State state;
		    state.info_raw.colortype = colortype;
		    state.info_raw.bitdepth = bitdepth;
		    size_t buffersize = lodepng_get_raw_size(w, h, &state.info_raw);
		    out.insert(out.end(), &buffer[0], &buffer[buffersize]);
		  }
		  lodepng_free(buffer);
		  return error;
		}

		unsigned decode(std::vector<uint8>& out, unsigned& w, unsigned& h,
		                const std::vector<uint8>& in, LodePNGColorType colortype, unsigned bitdepth) {
		  return decode(out, w, h, in.empty() ? 0 : &in[0], (unsigned)in.size(), colortype, bitdepth);
		}

		unsigned decode(std::vector<uint8>& out, unsigned& w, unsigned& h,
		                State& state,
		                const uint8* in, size_t insize) {
		  uint8* buffer = NULL;
		  unsigned error = lodepng_decode(&buffer, &w, &h, &state, in, insize);
		  if(buffer && !error) {
		    size_t buffersize = lodepng_get_raw_size(w, h, &state.info_raw);
		    out.insert(out.end(), &buffer[0], &buffer[buffersize]);
		  }
		  lodepng_free(buffer);
		  return error;
		}

		unsigned decode(std::vector<uint8>& out, unsigned& w, unsigned& h,
		                State& state,
		                const std::vector<uint8>& in) {
		  return decode(out, w, h, state, in.empty() ? 0 : &in[0], in.size());
		}

#if LODEPNG_COMPILE_DISK
		unsigned decode(std::vector<uint8>& out, unsigned& w, unsigned& h, const std::string& filename,
		                LodePNGColorType colortype, unsigned bitdepth) {
		  std::vector<uint8> buffer;
		  /* safe output values in case error happens */
		  w = h = 0;
		  unsigned error = load_file(buffer, filename);
		  if(error) return error;
		  return decode(out, w, h, buffer, colortype, bitdepth);
		}
#endif /* LODEPNG_COMPILE_DECODER */
#endif /* LODEPNG_COMPILE_DISK */

#if LODEPNG_COMPILE_ENCODER
		unsigned encode(std::vector<uint8>& out, const uint8* in, unsigned w, unsigned h,
		                LodePNGColorType colortype, unsigned bitdepth) {
		  uint8* buffer;
		  size_t buffersize;
		  unsigned error = lodepng_encode_memory(&buffer, &buffersize, in, w, h, colortype, bitdepth);
		  if(buffer) {
		    out.insert(out.end(), &buffer[0], &buffer[buffersize]);
		    lodepng_free(buffer);
		  }
		  return error;
		}

		unsigned encode(std::vector<uint8>& out,
		                const std::vector<uint8>& in, unsigned w, unsigned h,
		                LodePNGColorType colortype, unsigned bitdepth) {
		  if(lodepng_get_raw_size_lct(w, h, colortype, bitdepth) > in.size()) return 84;
		  return encode(out, in.empty() ? 0 : &in[0], w, h, colortype, bitdepth);
		}

		unsigned encode(std::vector<uint8>& out,
		                const uint8* in, unsigned w, unsigned h,
		                State& state) {
		  uint8* buffer;
		  size_t buffersize;
		  unsigned error = lodepng_encode(&buffer, &buffersize, in, w, h, &state);
		  if(buffer) {
		    out.insert(out.end(), &buffer[0], &buffer[buffersize]);
		    lodepng_free(buffer);
		  }
		  return error;
		}

		unsigned encode(std::vector<uint8>& out,
		                const std::vector<uint8>& in, unsigned w, unsigned h,
		                State& state) {
		  if(lodepng_get_raw_size(w, h, &state.info_raw) > in.size()) return 84;
		  return encode(out, in.empty() ? 0 : &in[0], w, h, state);
		}

#if LODEPNG_COMPILE_DISK
		unsigned encode(const std::string& filename,
		                const uint8* in, unsigned w, unsigned h,
		                LodePNGColorType colortype, unsigned bitdepth) {
		  std::vector<uint8> buffer;
		  unsigned error = encode(buffer, in, w, h, colortype, bitdepth);
		  if(!error) error = save_file(buffer, filename);
		  return error;
		}

		unsigned encode(const std::string& filename,
		                const std::vector<uint8>& in, unsigned w, unsigned h,
		                LodePNGColorType colortype, unsigned bitdepth) {
		  if(lodepng_get_raw_size_lct(w, h, colortype, bitdepth) > in.size()) return 84;
		  return encode(filename, in.empty() ? 0 : &in[0], w, h, colortype, bitdepth);
		}
#endif /* LODEPNG_COMPILE_DISK */
#endif /* LODEPNG_COMPILE_ENCODER */
#endif /* LODEPNG_COMPILE_PNG */
		} /* namespace lodepng */
#endif /*LODEPNG_COMPILE_CPP*/

	}
}
