diff options
Diffstat (limited to 'lib/lz4.c')
| -rw-r--r-- | lib/lz4.c | 178 |
1 files changed, 116 insertions, 62 deletions
@@ -1,6 +1,6 @@ /* LZ4 - Fast LZ compression algorithm - Copyright (C) 2011-2017, Yann Collet. + Copyright (C) 2011-present, Yann Collet. BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php) @@ -297,8 +297,9 @@ void LZ4_wildCopy(void* dstPtr, const void* srcPtr, void* dstEnd) #define MINMATCH 4 #define WILDCOPYLENGTH 8 -#define LASTLITERALS 5 -#define MFLIMIT (WILDCOPYLENGTH+MINMATCH) +#define LASTLITERALS 5 /* see ../doc/lz4_Block_format.md#parsing-restrictions */ +#define MFLIMIT 12 /* see ../doc/lz4_Block_format.md#parsing-restrictions */ +#define MATCH_SAFEGUARD_DISTANCE ((2*WILDCOPYLENGTH) - MINMATCH) /* ensure it's possible to write 2 x wildcopyLength without overflowing output buffer */ static const int LZ4_minLength = (MFLIMIT+1); #define KB *(1 <<10) @@ -483,9 +484,6 @@ typedef enum { clearedTable = 0, byPtr, byU32, byU16 } tableType_t; typedef enum { noDict = 0, withPrefix64k, usingExtDict, usingDictCtx } dict_directive; typedef enum { noDictIssue = 0, dictSmall } dictIssue_directive; -typedef enum { endOnOutputSize = 0, endOnInputSize = 1 } endCondition_directive; -typedef enum { full = 0, partial = 1 } earlyEnd_directive; - /*-************************************ * Local Utils @@ -496,6 +494,21 @@ int LZ4_compressBound(int isize) { return LZ4_COMPRESSBOUND(isize); } int LZ4_sizeofState() { return LZ4_STREAMSIZE; } +/*-************************************ +* Internal Definitions used in Tests +**************************************/ +#if defined (__cplusplus) +extern "C" { +#endif + +int LZ4_compress_forceExtDict (LZ4_stream_t* LZ4_stream, const char* source, char* dest, int inputSize); + +int LZ4_decompress_safe_forceExtDict(const char* in, char* out, int inSize, int outSize, const void* dict, size_t dictSize); + +#if defined (__cplusplus) +} +#endif + /*-****************************** * Compression functions ********************************/ @@ -669,9 +682,9 @@ LZ4_FORCE_INLINE int LZ4_compress_generic( /* the dictCtx currentOffset is indexed on the start of the dictionary, * while a dictionary in the current context precedes the currentOffset */ - const BYTE* dictBase = dictDirective == usingDictCtx ? - dictionary + dictSize - dictCtx->currentOffset : - dictionary + dictSize - startIndex; + const BYTE* dictBase = (dictDirective == usingDictCtx) ? + dictionary + dictSize - dictCtx->currentOffset : + dictionary + dictSize - startIndex; BYTE* op = (BYTE*) dest; BYTE* const olimit = op + maxOutputSize; @@ -699,7 +712,7 @@ LZ4_FORCE_INLINE int LZ4_compress_generic( cctx->dictSize += (U32)inputSize; } cctx->currentOffset += (U32)inputSize; - cctx->tableType = tableType; + cctx->tableType = (U16)tableType; if (inputSize<LZ4_minLength) goto _last_literals; /* Input too small, no compression (all literals) */ @@ -1370,26 +1383,32 @@ int LZ4_saveDict (LZ4_stream_t* LZ4_dict, char* safeBuffer, int dictSize) -/*-***************************** -* Decompression functions -*******************************/ +/*-******************************* + * Decompression functions + ********************************/ + +typedef enum { endOnOutputSize = 0, endOnInputSize = 1 } endCondition_directive; +typedef enum { decode_full_block = 0, partial_decode = 1 } earlyEnd_directive; + +#undef MIN +#define MIN(a,b) ( (a) < (b) ? (a) : (b) ) + /*! LZ4_decompress_generic() : * This generic decompression function covers all use cases. * It shall be instantiated several times, using different sets of directives. * Note that it is important for performance that this function really get inlined, * in order to remove useless branches during compilation optimization. */ -LZ4_FORCE_O2_GCC_PPC64LE -LZ4_FORCE_INLINE int LZ4_decompress_generic( +LZ4_FORCE_INLINE int +LZ4_decompress_generic( const char* const src, char* const dst, int srcSize, int outputSize, /* If endOnInput==endOnInputSize, this value is `dstCapacity` */ - int endOnInput, /* endOnOutputSize, endOnInputSize */ - int partialDecoding, /* full, partial */ - int targetOutputSize, /* only used if partialDecoding==partial */ - int dict, /* noDict, withPrefix64k, usingExtDict */ + endCondition_directive endOnInput, /* endOnOutputSize, endOnInputSize */ + earlyEnd_directive partialDecoding, /* full, partial */ + dict_directive dict, /* noDict, withPrefix64k, usingExtDict */ const BYTE* const lowPrefix, /* always <= dst, == dst when no prefix */ const BYTE* const dictStart, /* only if dict==usingExtDict */ const size_t dictSize /* note : = 0 if noDict */ @@ -1401,7 +1420,6 @@ LZ4_FORCE_INLINE int LZ4_decompress_generic( BYTE* op = (BYTE*) dst; BYTE* const oend = op + outputSize; BYTE* cpy; - BYTE* oexit = op + targetOutputSize; const BYTE* const dictEnd = (const BYTE*)dictStart + dictSize; const unsigned inc32table[8] = {0, 1, 2, 1, 0, 4, 4, 4}; @@ -1414,12 +1432,13 @@ LZ4_FORCE_INLINE int LZ4_decompress_generic( const BYTE* const shortiend = iend - (endOnInput ? 14 : 8) /*maxLL*/ - 2 /*offset*/; const BYTE* const shortoend = oend - (endOnInput ? 14 : 8) /*maxLL*/ - 18 /*maxML*/; - DEBUGLOG(5, "LZ4_decompress_generic (srcSize:%i)", srcSize); + DEBUGLOG(5, "LZ4_decompress_generic (srcSize:%i, dstSize:%i)", srcSize, outputSize); /* Special cases */ - if ((partialDecoding) && (oexit > oend-MFLIMIT)) oexit = oend-MFLIMIT; /* targetOutputSize too high => just decode everything */ + assert(lowPrefix <= op); + assert(src != NULL); if ((endOnInput) && (unlikely(outputSize==0))) return ((srcSize==1) && (*ip==0)) ? 0 : -1; /* Empty output buffer */ - if ((!endOnInput) && (unlikely(outputSize==0))) return (*ip==0?1:-1); + if ((!endOnInput) && (unlikely(outputSize==0))) return (*ip==0 ? 1 : -1); if ((endOnInput) && unlikely(srcSize==0)) return -1; /* Main Loop : decode sequences */ @@ -1428,7 +1447,7 @@ LZ4_FORCE_INLINE int LZ4_decompress_generic( size_t offset; unsigned const token = *ip++; - size_t length = token >> ML_BITS; /* literal length */ + size_t length = token >> ML_BITS; /* literal length */ assert(!endOnInput || ip <= iend); /* ip < iend before the increment */ @@ -1453,6 +1472,7 @@ LZ4_FORCE_INLINE int LZ4_decompress_generic( length = token & ML_MASK; /* match length */ offset = LZ4_readLE16(ip); ip += 2; match = op - offset; + assert(match <= op); /* check overflow */ /* Do not deal with overlapping matches. */ if ( (length != ML_MASK) @@ -1486,11 +1506,12 @@ LZ4_FORCE_INLINE int LZ4_decompress_generic( /* copy literals */ cpy = op+length; - if ( ((endOnInput) && ((cpy>(partialDecoding?oexit:oend-MFLIMIT)) || (ip+length>iend-(2+1+LASTLITERALS))) ) - || ((!endOnInput) && (cpy>oend-WILDCOPYLENGTH)) ) + LZ4_STATIC_ASSERT(MFLIMIT >= WILDCOPYLENGTH); + if ( ((endOnInput) && ((cpy>oend-MFLIMIT) || (ip+length>iend-(2+1+LASTLITERALS))) ) + || ((!endOnInput) && (cpy>oend-WILDCOPYLENGTH)) ) { if (partialDecoding) { - if (cpy > oend) goto _output_error; /* Error : write attempt beyond end of output buffer */ + if (cpy > oend) { cpy = oend; length = oend-op; } /* Partial decoding : stop in the middle of literal segment */ 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 */ @@ -1499,10 +1520,15 @@ LZ4_FORCE_INLINE int LZ4_decompress_generic( memcpy(op, ip, length); ip += length; op += length; - break; /* Necessarily EOF, due to parsing restrictions */ + if (!partialDecoding || (cpy == oend)) { + /* Necessarily EOF, due to parsing restrictions */ + break; + } + + } else { + LZ4_wildCopy(op, ip, cpy); /* may overwrite up to WILDCOPYLENGTH beyond cpy */ + ip += length; op = cpy; } - LZ4_wildCopy(op, ip, cpy); - ip += length; op = cpy; /* get offset */ offset = LZ4_readLE16(ip); ip+=2; @@ -1513,7 +1539,11 @@ LZ4_FORCE_INLINE int LZ4_decompress_generic( _copy_match: if ((checkOffset) && (unlikely(match + dictSize < lowPrefix))) goto _output_error; /* Error : offset outside buffers */ - LZ4_write32(op, (U32)offset); /* costs ~1%; silence an msan warning when offset==0 */ + if (!partialDecoding) { + assert(oend > op); + assert(oend - op >= 4); + LZ4_write32(op, 0); /* silence an msan warning when offset==0; costs <1%; */ + } /* note : when partialDecoding, there is no guarantee that at least 4 bytes remain available in output buffer */ if (length == ML_MASK) { unsigned s; @@ -1526,21 +1556,24 @@ _copy_match: } length += MINMATCH; - /* check external dictionary */ + /* match starting within external dictionary */ if ((dict==usingExtDict) && (match < lowPrefix)) { - if (unlikely(op+length > oend-LASTLITERALS)) goto _output_error; /* doesn't respect parsing restriction */ + if (unlikely(op+length > oend-LASTLITERALS)) { + if (partialDecoding) length = MIN(length, (size_t)(oend-op)); + else 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 fits entirely within external dictionary : just copy */ memmove(op, dictEnd - (lowPrefix-match), length); op += length; } else { - /* match encompass external dictionary and current block */ - size_t const copySize = (size_t)(lowPrefix-match); + /* match stretches into both external dictionary and current block */ + size_t const copySize = (size_t)(lowPrefix - match); size_t const restSize = length - copySize; memcpy(op, dictEnd - copySize, copySize); op += copySize; - if (restSize > (size_t)(op-lowPrefix)) { /* overlap copy */ + if (restSize > (size_t)(op - lowPrefix)) { /* overlap copy */ BYTE* const endOfMatch = op + restSize; const BYTE* copyFrom = lowPrefix; while (op < endOfMatch) *op++ = *copyFrom++; @@ -1553,6 +1586,23 @@ _copy_match: /* copy match within block */ cpy = op + length; + + /* partialDecoding : may not respect endBlock parsing restrictions */ + assert(op<=oend); + if (partialDecoding && (cpy > oend-MATCH_SAFEGUARD_DISTANCE)) { + size_t const mlen = MIN(length, (size_t)(oend-op)); + const BYTE* const matchEnd = match + mlen; + BYTE* const copyEnd = op + mlen; + if (matchEnd > op) { /* overlap copy */ + while (op < copyEnd) *op++ = *match++; + } else { + memcpy(op, match, mlen); + } + op = copyEnd; + if (op==oend) break; + continue; + } + if (unlikely(offset<8)) { op[0] = match[0]; op[1] = match[1]; @@ -1561,23 +1611,26 @@ _copy_match: match += inc32table[offset]; memcpy(op+4, match, 4); match -= dec64table[offset]; - } else { memcpy(op, match, 8); match+=8; } + } else { + memcpy(op, match, 8); + match += 8; + } op += 8; - if (unlikely(cpy>oend-12)) { - BYTE* const oCopyLimit = oend-(WILDCOPYLENGTH-1); + if (unlikely(cpy > oend-MATCH_SAFEGUARD_DISTANCE)) { + BYTE* const oCopyLimit = oend - (WILDCOPYLENGTH-1); if (cpy > oend-LASTLITERALS) goto _output_error; /* Error : last LASTLITERALS bytes must be literals (uncompressed) */ if (op < oCopyLimit) { LZ4_wildCopy(op, match, oCopyLimit); match += oCopyLimit - op; op = oCopyLimit; } - while (op<cpy) *op++ = *match++; + while (op < cpy) *op++ = *match++; } else { memcpy(op, match, 8); - if (length>16) LZ4_wildCopy(op+8, match+8, cpy); + if (length > 16) LZ4_wildCopy(op+8, match+8, cpy); } - op = cpy; /* correction */ + op = cpy; /* wildcopy correction */ } /* end of decoding */ @@ -1598,23 +1651,24 @@ LZ4_FORCE_O2_GCC_PPC64LE int LZ4_decompress_safe(const char* source, char* dest, int compressedSize, int maxDecompressedSize) { return LZ4_decompress_generic(source, dest, compressedSize, maxDecompressedSize, - endOnInputSize, full, 0, noDict, + endOnInputSize, decode_full_block, noDict, (BYTE*)dest, NULL, 0); } LZ4_FORCE_O2_GCC_PPC64LE -int LZ4_decompress_safe_partial(const char* source, char* dest, int compressedSize, int targetOutputSize, int maxDecompressedSize) +int LZ4_decompress_safe_partial(const char* src, char* dst, int compressedSize, int targetOutputSize, int dstCapacity) { - return LZ4_decompress_generic(source, dest, compressedSize, maxDecompressedSize, - endOnInputSize, partial, targetOutputSize, - noDict, (BYTE*)dest, NULL, 0); + dstCapacity = MIN(targetOutputSize, dstCapacity); + return LZ4_decompress_generic(src, dst, compressedSize, dstCapacity, + endOnInputSize, partial_decode, + noDict, (BYTE*)dst, NULL, 0); } LZ4_FORCE_O2_GCC_PPC64LE int LZ4_decompress_fast(const char* source, char* dest, int originalSize) { return LZ4_decompress_generic(source, dest, 0, originalSize, - endOnOutputSize, full, 0, withPrefix64k, + endOnOutputSize, decode_full_block, withPrefix64k, (BYTE*)dest - 64 KB, NULL, 0); } @@ -1624,7 +1678,7 @@ LZ4_FORCE_O2_GCC_PPC64LE /* Exported, an obsolete API function. */ int LZ4_decompress_safe_withPrefix64k(const char* source, char* dest, int compressedSize, int maxOutputSize) { return LZ4_decompress_generic(source, dest, compressedSize, maxOutputSize, - endOnInputSize, full, 0, withPrefix64k, + endOnInputSize, decode_full_block, withPrefix64k, (BYTE*)dest - 64 KB, NULL, 0); } @@ -1641,17 +1695,17 @@ static int LZ4_decompress_safe_withSmallPrefix(const char* source, char* dest, i size_t prefixSize) { return LZ4_decompress_generic(source, dest, compressedSize, maxOutputSize, - endOnInputSize, full, 0, noDict, + endOnInputSize, decode_full_block, noDict, (BYTE*)dest-prefixSize, NULL, 0); } -LZ4_FORCE_O2_GCC_PPC64LE /* Exported under another name, for tests/fullbench.c */ -#define LZ4_decompress_safe_extDict LZ4_decompress_safe_forceExtDict -int LZ4_decompress_safe_extDict(const char* source, char* dest, int compressedSize, int maxOutputSize, - const void* dictStart, size_t dictSize) +LZ4_FORCE_O2_GCC_PPC64LE +int LZ4_decompress_safe_forceExtDict(const char* source, char* dest, + int compressedSize, int maxOutputSize, + const void* dictStart, size_t dictSize) { return LZ4_decompress_generic(source, dest, compressedSize, maxOutputSize, - endOnInputSize, full, 0, usingExtDict, + endOnInputSize, decode_full_block, usingExtDict, (BYTE*)dest, (const BYTE*)dictStart, dictSize); } @@ -1660,7 +1714,7 @@ static int LZ4_decompress_fast_extDict(const char* source, char* dest, int origi const void* dictStart, size_t dictSize) { return LZ4_decompress_generic(source, dest, 0, originalSize, - endOnOutputSize, full, 0, usingExtDict, + endOnOutputSize, decode_full_block, usingExtDict, (BYTE*)dest, (const BYTE*)dictStart, dictSize); } @@ -1673,7 +1727,7 @@ int LZ4_decompress_safe_doubleDict(const char* source, char* dest, int compresse size_t prefixSize, const void* dictStart, size_t dictSize) { return LZ4_decompress_generic(source, dest, compressedSize, maxOutputSize, - endOnInputSize, full, 0, usingExtDict, + endOnInputSize, decode_full_block, usingExtDict, (BYTE*)dest-prefixSize, (const BYTE*)dictStart, dictSize); } @@ -1682,7 +1736,7 @@ int LZ4_decompress_fast_doubleDict(const char* source, char* dest, int originalS size_t prefixSize, const void* dictStart, size_t dictSize) { return LZ4_decompress_generic(source, dest, 0, originalSize, - endOnOutputSize, full, 0, usingExtDict, + endOnOutputSize, decode_full_block, usingExtDict, (BYTE*)dest-prefixSize, (const BYTE*)dictStart, dictSize); } @@ -1773,8 +1827,8 @@ int LZ4_decompress_safe_continue (LZ4_streamDecode_t* LZ4_streamDecode, const ch /* The buffer wraps around, or they're switching to another buffer. */ lz4sd->extDictSize = lz4sd->prefixSize; lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize; - result = LZ4_decompress_safe_extDict(source, dest, compressedSize, maxOutputSize, - lz4sd->externalDict, lz4sd->extDictSize); + result = LZ4_decompress_safe_forceExtDict(source, dest, compressedSize, maxOutputSize, + lz4sd->externalDict, lz4sd->extDictSize); if (result <= 0) return result; lz4sd->prefixSize = result; lz4sd->prefixEnd = (BYTE*)dest + result; @@ -1834,7 +1888,7 @@ int LZ4_decompress_safe_usingDict(const char* source, char* dest, int compressed return LZ4_decompress_safe_withPrefix64k(source, dest, compressedSize, maxOutputSize); return LZ4_decompress_safe_withSmallPrefix(source, dest, compressedSize, maxOutputSize, dictSize); } - return LZ4_decompress_safe_extDict(source, dest, compressedSize, maxOutputSize, dictStart, dictSize); + return LZ4_decompress_safe_forceExtDict(source, dest, compressedSize, maxOutputSize, dictStart, dictSize); } int LZ4_decompress_fast_usingDict(const char* source, char* dest, int originalSize, const char* dictStart, int dictSize) |