diff options
-rwxr-xr-x | lz4.c | 41 |
1 files changed, 22 insertions, 19 deletions
@@ -411,6 +411,7 @@ static unsigned LZ4_count(const BYTE* pIn, const BYTE* pRef, const BYTE* pInLimi return (unsigned)(pIn - pStart); } + static int LZ4_compress_generic( void* ctx, const char* source, @@ -436,11 +437,11 @@ static int LZ4_compress_generic( const BYTE* const matchlimit = iend - LASTLITERALS; BYTE* op = (BYTE*) dest; - BYTE* const oend = op + maxOutputSize; + BYTE* const olimit = op + maxOutputSize; const int skipStrength = SKIPSTRENGTH; U32 forwardH; - size_t delta=0; + size_t refDelta=0; /* Init conditions */ if ((U32)inputSize > (U32)LZ4_MAX_INPUT_SIZE) return 0; /* Unsupported input size, too large (or negative) */ @@ -486,30 +487,31 @@ static int LZ4_compress_generic( ref = LZ4_getPositionOnHash(h, ctx, tableType, base); if (dict==usingExtDict) { - delta = (ip-ref); if (ref<(const BYTE*)source) { - ref += dictDelta; + refDelta = dictDelta; lowLimit = dictionary; } - else lowLimit = (const BYTE*)source; + else + { + refDelta = 0; + lowLimit = (const BYTE*)source; + } } if (unlikely(ip > mflimit)) goto _last_literals; forwardH = LZ4_hashPosition(forwardIp, tableType); LZ4_putPositionOnHash(ip, h, ctx, tableType, base); - } while (((dict==usingExtDict) && (delta>MAX_DISTANCE)) || - ((dict!=usingExtDict) && (ref + MAX_DISTANCE < ip)) || - (A32(ref) != A32(ip)) ); + } while ( ((tableType==byU16)? 0 : (ref + MAX_DISTANCE < ip)) || (A32(ref+refDelta) != A32(ip)) ); /* Catch up */ - while ((ip>anchor) && (ref > lowLimit) && (unlikely(ip[-1]==ref[-1]))) { ip--; ref--; } + while ((ip>anchor) && (ref+refDelta > lowLimit) && (unlikely(ip[-1]==ref[refDelta-1]))) { ip--; ref--; } // refDelta costs some performance { /* Encode Literal length */ unsigned litLength = (unsigned)(ip - anchor); token = op++; - if ((outputLimited) && (unlikely(op + litLength + (2 + 1 + LASTLITERALS) + (litLength/255) > oend))) return 0; /* Check output limit */ + if ((outputLimited) && (unlikely(op + litLength + (2 + 1 + LASTLITERALS) + (litLength/255) > olimit))) return 0; /* Check output limit */ if (litLength>=RUN_MASK) { int len = (int)litLength-RUN_MASK; @@ -525,10 +527,10 @@ static int LZ4_compress_generic( _next_match: /* Encode Offset */ - if (dict==usingExtDict) LZ4_WRITE_LITTLEENDIAN_16(op, delta) - else LZ4_WRITE_LITTLEENDIAN_16(op,(U16)(ip-ref)); + LZ4_WRITE_LITTLEENDIAN_16(op,(U16)(ip-ref)); /* Encode MatchLength */ + ref += refDelta; { unsigned matchLength; @@ -553,7 +555,7 @@ _next_match: if (matchLength>=ML_MASK) { - if ((outputLimited) && (unlikely(op + (1 + LASTLITERALS) + (matchLength>>8) > oend))) return 0; /* Check output limit */ + if ((outputLimited) && (unlikely(op + (1 + LASTLITERALS) + (matchLength>>8) > olimit))) return 0; /* Check output limit */ *token += ML_MASK; matchLength -= ML_MASK; for (; matchLength > 509 ; matchLength-=510) { *op++ = 255; *op++ = 255; } @@ -575,18 +577,19 @@ _next_match: ref = LZ4_getPosition(ip, ctx, tableType, base); if (dict==usingExtDict) { - delta = ip-ref; if (ref<(const BYTE*)source) { - ref += dictDelta; + refDelta = dictDelta; lowLimit = dictionary; } - else lowLimit = (const BYTE*)source; + else + { + refDelta = 0; + lowLimit = (const BYTE*)source; + } } LZ4_putPosition(ip, ctx, tableType, base); - if ((((dict==usingExtDict) && (delta<=MAX_DISTANCE)) || - ((dict!=usingExtDict) && (ref + MAX_DISTANCE >= ip))) && - (A32(ref) == A32(ip))) { token = op++; *token=0; goto _next_match; } + if ( (ref+MAX_DISTANCE>=ip) && (A32(ref+refDelta)==A32(ip)) ) { token=op++; *token=0; goto _next_match; } /* Prepare next loop */ forwardH = LZ4_hashPosition(++ip, tableType); |