{
    "Function": "concatStorage",
    "File": "src/contracts/libraries/BytesLib.sol",
    "Parent Contracts": [],
    "High-Level Calls": [],
    "Internal Calls": [
        "sload(uint256)",
        "sstore(uint256,uint256)",
        "mload(uint256)",
        "sload(uint256)",
        "keccak256(uint256,uint256)",
        "sstore(uint256,uint256)",
        "mload(uint256)",
        "sstore(uint256,uint256)",
        "mstore(uint256,uint256)",
        "mload(uint256)",
        "mload(uint256)",
        "sstore(uint256,uint256)",
        "sstore(uint256,uint256)",
        "mload(uint256)",
        "sstore(uint256,uint256)",
        "mstore(uint256,uint256)",
        "mload(uint256)",
        "sstore(uint256,uint256)",
        "keccak256(uint256,uint256)",
        "mload(uint256)",
        "sstore(uint256,uint256)",
        "mload(uint256)",
        "sstore(uint256,uint256)"
    ],
    "Library Calls": [],
    "Low-Level Calls": [],
    "Code": "function concatStorage(bytes storage _preBytes, bytes memory _postBytes) internal {\n        assembly {\n            // Read the first 32 bytes of _preBytes storage, which is the length\n            // of the array. (We don't need to use the offset into the slot\n            // because arrays use the entire slot.)\n            let fslot := sload(_preBytes.slot)\n            // Arrays of 31 bytes or less have an even value in their slot,\n            // while longer arrays have an odd value. The actual length is\n            // the slot divided by two for odd values, and the lowest order\n            // byte divided by two for even values.\n            // If the slot is even, bitwise and the slot with 255 and divide by\n            // two to get the length. If the slot is odd, bitwise and the slot\n            // with -1 and divide by two.\n            let slength := div(and(fslot, sub(mul(0x100, iszero(and(fslot, 1))), 1)), 2)\n            let mlength := mload(_postBytes)\n            let newlength := add(slength, mlength)\n            // slength can contain both the length and contents of the array\n            // if length < 32 bytes so let's prepare for that\n            // v. http://solidity.readthedocs.io/en/latest/miscellaneous.html#layout-of-state-variables-in-storage\n            switch add(lt(slength, 32), lt(newlength, 32))\n            case 2 {\n                // Since the new array still fits in the slot, we just need to\n                // update the contents of the slot.\n                // uint256(bytes_storage) = uint256(bytes_storage) + uint256(bytes_memory) + new_length\n                sstore(\n                    _preBytes.slot,\n                    // all the modifications to the slot are inside this\n                    // next block\n                    add(\n                        // we can just add to the slot contents because the\n                        // bytes we want to change are the LSBs\n                        fslot,\n                        add(\n                            mul(\n                                div(\n                                    // load the bytes from memory\n                                    mload(add(_postBytes, 0x20)),\n                                    // zero all bytes to the right\n                                    exp(0x100, sub(32, mlength))\n                                ),\n                                // and now shift left the number of bytes to\n                                // leave space for the length in the slot\n                                exp(0x100, sub(32, newlength))\n                            ),\n                            // increase length by the double of the memory\n                            // bytes length\n                            mul(mlength, 2)\n                        )\n                    )\n                )\n            }\n            case 1 {\n                // The stored value fits in the slot, but the combined value\n                // will exceed it.\n                // get the keccak hash to get the contents of the array\n                mstore(0x0, _preBytes.slot)\n                let sc := add(keccak256(0x0, 0x20), div(slength, 32))\n\n                // save new length\n                sstore(_preBytes.slot, add(mul(newlength, 2), 1))\n\n                // The contents of the _postBytes array start 32 bytes into\n                // the structure. Our first read should obtain the `submod`\n                // bytes that can fit into the unused space in the last word\n                // of the stored array. To get this, we read 32 bytes starting\n                // from `submod`, so the data we read overlaps with the array\n                // contents by `submod` bytes. Masking the lowest-order\n                // `submod` bytes allows us to add that value directly to the\n                // stored value.\n\n                let submod := sub(32, slength)\n                let mc := add(_postBytes, submod)\n                let end := add(_postBytes, mlength)\n                let mask := sub(exp(0x100, submod), 1)\n\n                sstore(\n                    sc,\n                    add(\n                        and(fslot, 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff00),\n                        and(mload(mc), mask)\n                    )\n                )\n\n                for {\n                    mc := add(mc, 0x20)\n                    sc := add(sc, 1)\n                } lt(mc, end) {\n                    sc := add(sc, 1)\n                    mc := add(mc, 0x20)\n                } { sstore(sc, mload(mc)) }\n\n                mask := exp(0x100, sub(mc, end))\n\n                sstore(sc, mul(div(mload(mc), mask), mask))\n            }\n            default {\n                // get the keccak hash to get the contents of the array\n                mstore(0x0, _preBytes.slot)\n                // Start copying to the last used word of the stored array.\n                let sc := add(keccak256(0x0, 0x20), div(slength, 32))\n\n                // save new length\n                sstore(_preBytes.slot, add(mul(newlength, 2), 1))\n\n                // Copy over the first `submod` bytes of the new data as in\n                // case 1 above.\n                let slengthmod := mod(slength, 32)\n                // solhint-disable-next-line no-unused-vars\n                let mlengthmod := mod(mlength, 32)\n                let submod := sub(32, slengthmod)\n                let mc := add(_postBytes, submod)\n                let end := add(_postBytes, mlength)\n                let mask := sub(exp(0x100, submod), 1)\n\n                sstore(sc, add(sload(sc), and(mload(mc), mask)))\n\n                for {\n                    sc := add(sc, 1)\n                    mc := add(mc, 0x20)\n                } lt(mc, end) {\n                    sc := add(sc, 1)\n                    mc := add(mc, 0x20)\n                } { sstore(sc, mload(mc)) }\n\n                mask := exp(0x100, sub(mc, end))\n\n                sstore(sc, mul(div(mload(mc), mask), mask))\n            }\n        }\n    }"
}