/* LZ4 - Fast LZ compression algorithm Copyright (C) 2011-2015, Yann Collet. SPDX-License-Identifier: BSD-2-Clause You can contact the author at : - LZ4 source repository : https://github.com/Cyan4973/lz4 - LZ4 public forum : https://groups.google.com/forum/#!forum/lz4c */ /************************************** * Reading and writing into memory **************************************/ /* customized version of memcpy, which may overwrite up to 7 bytes beyond dstEnd */ static void LZ4_wildCopy(void* dstPtr, const void* srcPtr, void* dstEnd) { BYTE* d = (BYTE*)dstPtr; const BYTE* s = (const BYTE*)srcPtr; BYTE* e = (BYTE*)dstEnd; do { LZ4_copy8(d,s); d+=8; s+=8; } while (d oend-MFLIMIT)) oexit = oend-MFLIMIT; /* targetOutputSize too high => decode everything */ if ((endOnInput) && (unlikely(outputSize==0))) return ((inputSize==1) && (*ip==0)) ? 0 : -1; /* Empty output buffer */ if ((!endOnInput) && (unlikely(outputSize==0))) return (*ip==0?1:-1); /* Main Loop */ while (1) { unsigned token; size_t length; const BYTE* match; /* get literal length */ token = *ip++; if ((length=(token>>ML_BITS)) == RUN_MASK) { unsigned s; do { s = *ip++; length += s; } while (likely((endOnInput)?ip(partialDecoding?oexit:oend-MFLIMIT)) || (ip+length>iend-(2+1+LASTLITERALS))) ) || ((!endOnInput) && (cpy>oend-COPYLENGTH))) { if (partialDecoding) { if (cpy > oend) goto _output_error; /* Error : write attempt beyond end of output buffer */ if ((endOnInput) && (ip+length > iend)) goto _output_error; /* Error : read attempt beyond end of input buffer */ } else { if ((!endOnInput) && (cpy != oend)) goto _output_error; /* Error : block decoding must stop exactly there */ if ((endOnInput) && ((ip+length != iend) || (cpy > oend))) goto _output_error; /* Error : input must be consumed */ } memcpy(op, ip, length); ip += length; op += length; break; /* Necessarily EOF, due to parsing restrictions */ } LZ4_wildCopy(op, ip, cpy); ip += length; op = cpy; /* get offset */ match = cpy - LZ4_readLE16(ip); ip+=2; if ((checkOffset) && (unlikely(match < lowLimit))) goto _output_error; /* Error : offset outside destination buffer */ /* get matchlength */ length = token & ML_MASK; if (length == ML_MASK) { unsigned s; do { if ((endOnInput) && (ip > iend-LASTLITERALS)) goto _output_error; s = *ip++; length += s; } while (s==255); if ((safeDecode) && unlikely((size_t)(op+length)<(size_t)op)) goto _output_error; /* overflow detection */ } length += MINMATCH; /* check external dictionary */ if ((dict==usingExtDict) && (match < lowPrefix)) { if (unlikely(op+length > oend-LASTLITERALS)) goto _output_error; /* doesn't respect parsing restriction */ if (length <= (size_t)(lowPrefix-match)) { /* match can be copied as a single segment from external dictionary */ match = dictEnd - (lowPrefix-match); memmove(op, match, length); op += length; } else { /* match encompass external dictionary and current segment */ size_t copySize = (size_t)(lowPrefix-match); memcpy(op, dictEnd - copySize, copySize); op += copySize; copySize = length - copySize; if (copySize > (size_t)(op-lowPrefix)) /* overlap within current segment */ { BYTE* const endOfMatch = op + copySize; const BYTE* copyFrom = lowPrefix; while (op < endOfMatch) *op++ = *copyFrom++; } else { memcpy(op, lowPrefix, copySize); op += copySize; } } continue; } /* copy repeated sequence */ cpy = op + length; if (unlikely((op-match)<8)) { const size_t dec64 = dec64table[op-match]; op[0] = match[0]; op[1] = match[1]; op[2] = match[2]; op[3] = match[3]; match += dec32table[op-match]; LZ4_copy4(op+4, match); op += 8; match -= dec64; } else { LZ4_copy8(op, match); op+=8; match+=8; } if (unlikely(cpy>oend-12)) { if (cpy > oend-LASTLITERALS) goto _output_error; /* Error : last LASTLITERALS bytes must be literals */ if (op < oend-8) { LZ4_wildCopy(op, match, oend-8); match += (oend-8) - op; op = oend-8; } while (op