File size: 4,631 Bytes
d843a8a |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 |
#!/usr/bin/env python3
import json
import sys
from dataclasses import dataclass
# The basic idea is to find named character references using binary
# search. Since entity strings may not have a terminator, this doesn't
# work if one entity string is a prefix of another. In this case,
# we branch to a subtable after matching the prefix.
#
# We create separate initial tables based on the first character
# of the entity name.
#
# The following tables are generated:
#
# htmlEntAlpha: start and end of initial tables, indexing into
# htmlEntValues
# htmlEntValues: concatenation of all table values, which index into
# htmlEntStrings
# htmlEntStrings: variable sized records containing entity name,
# replacement and optionally the position of a
# subtable
try:
with open('entities.json') as json_data:
ents = json.load(json_data)
except FileNotFoundError:
print('entities.json not found, try curl -LJO',
'https://html.spec.whatwg.org/entities.json')
sys.exit(1)
def to_cchars(s):
r = []
for c in s.encode():
if c >= 0x20 and c <= 0x7E and c != ord("'") and c != ord('\\'):
v = f"'{chr(c)}'"
else:
v = c
r += [ v ]
return r
@dataclass
class PrefixStackEntry:
prefix: str
table_id: int
@dataclass
class AlphaFixup:
table_id: int
char: int
@dataclass
class StringFixup:
table_id: int
string_index: int
super_table_id: int
super_offset: int
# Remove entity strings without trailing semicolon
keys = (key for key in ents.keys() if key.endswith(';'))
# Sort entity strings
keys = sorted(keys, key=lambda k: k[1:-1])
strings = []
tables = []
prefix_stack = []
alpha_fixups = []
string_fixups = []
for i in range(64):
tables.append([])
for i, key in enumerate(keys):
name = key[1:-1]
next_name = None
if i + 1 < len(keys):
next_name = keys[i+1][1:-1]
while prefix_stack and not name.startswith(prefix_stack[-1].prefix):
prefix_stack.pop()
# First character is initial prefix
if not prefix_stack:
table_id = len(tables)
tables.append([])
prefix_stack.append(PrefixStackEntry(name[0], table_id))
alpha_fixups.append(AlphaFixup(table_id, ord(name[0]) % 64))
string_index = len(strings)
table = tables[prefix_stack[-1].table_id]
table_index = len(table)
table.append(string_index)
name_offset = len(prefix_stack[-1].prefix)
name_chars = to_cchars(name[name_offset:])
repl_chars = to_cchars(ents[key]['characters'])
semicolon_flag = 0
if key[:-1] in ents:
semicolon_flag = 0x80
if next_name and next_name.startswith(name):
# Create subtable
strings += [
len(name_chars) | semicolon_flag | 0x40, *name_chars,
0, 0, # subtable position, to be fixed up
len(repl_chars), *repl_chars,
]
table_id = len(tables)
tables.append([])
fixup_index = string_index + 1 + len(name_chars)
string_fixups.append(StringFixup(
table_id, fixup_index, prefix_stack[-1].table_id, table_index,
))
prefix_stack.append(PrefixStackEntry(name, table_id))
else:
strings += [
len(name_chars) | semicolon_flag, *name_chars,
len(repl_chars), *repl_chars,
]
# Concat tables and record ranges
ranges = [ 0 ]
values = []
for table in tables:
values += table
ranges.append(len(values))
# Create alpha table
alpha = [ 0 ] * (59 * 3)
for fixup in alpha_fixups:
table_id, c = fixup.table_id, fixup.char
start = ranges[table_id]
end = ranges[table_id+1]
alpha[c*3:c*3+3] = [ start & 0xFF, start >> 8, end - start ]
# Fix up subtable positions
for fixup in string_fixups:
table_id, i = fixup.table_id, fixup.string_index
start = ranges[table_id]
end = ranges[table_id+1]
super_index = ranges[fixup.super_table_id] + fixup.super_offset
strings[i:i+2] = [ start - super_index, end - start ]
# Print tables
def gen_table(ctype, cname, values, fmt, elems_per_line):
count = len(values)
r = ''
for i in range(count):
if i != 0: r += ','
if i % elems_per_line == 0: r += '\n '
else: r += ' '
r += fmt % values[i]
return f'static const {ctype} {cname}[{count}] = {{{r}\n}};\n'
print(gen_table('unsigned char', 'htmlEntAlpha', alpha, '%3d', 15))
print(gen_table('unsigned short', 'htmlEntValues', values, '%5d', 10))
print(gen_table('unsigned char', 'htmlEntStrings', strings, '%3s', 15))
|