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Diffstat (limited to 'lib/lz4/lz4hc.c')
| -rw-r--r-- | lib/lz4/lz4hc.c | 1343 |
1 files changed, 0 insertions, 1343 deletions
diff --git a/lib/lz4/lz4hc.c b/lib/lz4/lz4hc.c deleted file mode 100644 index 4bdf96e..0000000 --- a/lib/lz4/lz4hc.c +++ /dev/null @@ -1,1343 +0,0 @@ -/* - LZ4 HC - High Compression Mode of LZ4 - Copyright (C) 2011-2017, Yann Collet. - - BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php) - - Redistribution and use in source and binary forms, with or without - modification, are permitted provided that the following conditions are - met: - - * Redistributions of source code must retain the above copyright - notice, this list of conditions and the following disclaimer. - * Redistributions in binary form must reproduce the above - copyright notice, this list of conditions and the following disclaimer - in the documentation and/or other materials provided with the - distribution. - - THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS - "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT - LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR - A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT - OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, - SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT - LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, - DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY - THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT - (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE - OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. - - You can contact the author at : - - LZ4 source repository : https://github.com/lz4/lz4 - - LZ4 public forum : https://groups.google.com/forum/#!forum/lz4c -*/ -/* note : lz4hc is not an independent module, it requires lz4.h/lz4.c for proper compilation */ - - -/* ************************************* -* Tuning Parameter -***************************************/ - -/*! HEAPMODE : - * Select how default compression function will allocate workplace memory, - * in stack (0:fastest), or in heap (1:requires malloc()). - * Since workplace is rather large, heap mode is recommended. - */ -#ifndef LZ4HC_HEAPMODE -# define LZ4HC_HEAPMODE 1 -#endif - - -/*=== Dependency ===*/ -#define LZ4_HC_STATIC_LINKING_ONLY -#include "lz4hc.h" - - -/*=== Common LZ4 definitions ===*/ -#if defined(__GNUC__) -# pragma GCC diagnostic ignored "-Wunused-function" -#endif -#if defined (__clang__) -# pragma clang diagnostic ignored "-Wunused-function" -#endif - -/*=== Enums ===*/ -typedef enum { noDictCtx, usingDictCtxHc } dictCtx_directive; - - -#define LZ4_COMMONDEFS_ONLY -#ifndef LZ4_SRC_INCLUDED -#include "lz4.c" /* LZ4_count, constants, mem */ -#endif - -/*=== Constants ===*/ -#define OPTIMAL_ML (int)((ML_MASK-1)+MINMATCH) -#define LZ4_OPT_NUM (1<<12) - - -/*=== Macros ===*/ -#define MIN(a,b) ( (a) < (b) ? (a) : (b) ) -#define MAX(a,b) ( (a) > (b) ? (a) : (b) ) -#define HASH_FUNCTION(i) (((i) * 2654435761U) >> ((MINMATCH*8)-LZ4HC_HASH_LOG)) -#define DELTANEXTMAXD(p) chainTable[(p) & LZ4HC_MAXD_MASK] /* flexible, LZ4HC_MAXD dependent */ -#define DELTANEXTU16(table, pos) table[(U16)(pos)] /* faster */ -/* Make fields passed to, and updated by LZ4HC_encodeSequence explicit */ -#define UPDATABLE(ip, op, anchor) &ip, &op, &anchor - -static U32 LZ4HC_hashPtr(const void* ptr) { return HASH_FUNCTION(LZ4_read32(ptr)); } - - -/************************************** -* HC Compression -**************************************/ -static void LZ4HC_clearTables (LZ4HC_CCtx_internal* hc4) -{ - MEM_INIT((void*)hc4->hashTable, 0, sizeof(hc4->hashTable)); - MEM_INIT(hc4->chainTable, 0xFF, sizeof(hc4->chainTable)); -} - -static void LZ4HC_init_internal (LZ4HC_CCtx_internal* hc4, const BYTE* start) -{ - uptrval startingOffset = (uptrval)(hc4->end - hc4->base); - if (startingOffset > 1 GB) { - LZ4HC_clearTables(hc4); - startingOffset = 0; - } - startingOffset += 64 KB; - hc4->nextToUpdate = (U32) startingOffset; - hc4->base = start - startingOffset; - hc4->end = start; - hc4->dictBase = start - startingOffset; - hc4->dictLimit = (U32) startingOffset; - hc4->lowLimit = (U32) startingOffset; -} - - -/* Update chains up to ip (excluded) */ -LZ4_FORCE_INLINE void LZ4HC_Insert (LZ4HC_CCtx_internal* hc4, const BYTE* ip) -{ - U16* const chainTable = hc4->chainTable; - U32* const hashTable = hc4->hashTable; - const BYTE* const base = hc4->base; - U32 const target = (U32)(ip - base); - U32 idx = hc4->nextToUpdate; - - while (idx < target) { - U32 const h = LZ4HC_hashPtr(base+idx); - size_t delta = idx - hashTable[h]; - if (delta>LZ4_DISTANCE_MAX) delta = LZ4_DISTANCE_MAX; - DELTANEXTU16(chainTable, idx) = (U16)delta; - hashTable[h] = idx; - idx++; - } - - hc4->nextToUpdate = target; -} - -/** LZ4HC_countBack() : - * @return : negative value, nb of common bytes before ip/match */ -LZ4_FORCE_INLINE -int LZ4HC_countBack(const BYTE* const ip, const BYTE* const match, - const BYTE* const iMin, const BYTE* const mMin) -{ - int back = 0; - int const min = (int)MAX(iMin - ip, mMin - match); - assert(min <= 0); - assert(ip >= iMin); assert((size_t)(ip-iMin) < (1U<<31)); - assert(match >= mMin); assert((size_t)(match - mMin) < (1U<<31)); - while ( (back > min) - && (ip[back-1] == match[back-1]) ) - back--; - return back; -} - -#if defined(_MSC_VER) -# define LZ4HC_rotl32(x,r) _rotl(x,r) -#else -# define LZ4HC_rotl32(x,r) ((x << r) | (x >> (32 - r))) -#endif - - -static U32 LZ4HC_rotatePattern(size_t const rotate, U32 const pattern) -{ - size_t const bitsToRotate = (rotate & (sizeof(pattern) - 1)) << 3; - if (bitsToRotate == 0) - return pattern; - return LZ4HC_rotl32(pattern, (int)bitsToRotate); -} - -/* LZ4HC_countPattern() : - * pattern32 must be a sample of repetitive pattern of length 1, 2 or 4 (but not 3!) */ -static unsigned -LZ4HC_countPattern(const BYTE* ip, const BYTE* const iEnd, U32 const pattern32) -{ - const BYTE* const iStart = ip; - reg_t const pattern = (sizeof(pattern)==8) ? (reg_t)pattern32 + (((reg_t)pattern32) << 32) : pattern32; - - while (likely(ip < iEnd-(sizeof(pattern)-1))) { - reg_t const diff = LZ4_read_ARCH(ip) ^ pattern; - if (!diff) { ip+=sizeof(pattern); continue; } - ip += LZ4_NbCommonBytes(diff); - return (unsigned)(ip - iStart); - } - - if (LZ4_isLittleEndian()) { - reg_t patternByte = pattern; - while ((ip<iEnd) && (*ip == (BYTE)patternByte)) { - ip++; patternByte >>= 8; - } - } else { /* big endian */ - U32 bitOffset = (sizeof(pattern)*8) - 8; - while (ip < iEnd) { - BYTE const byte = (BYTE)(pattern >> bitOffset); - if (*ip != byte) break; - ip ++; bitOffset -= 8; - } - } - - return (unsigned)(ip - iStart); -} - -/* LZ4HC_reverseCountPattern() : - * pattern must be a sample of repetitive pattern of length 1, 2 or 4 (but not 3!) - * read using natural platform endianess */ -static unsigned -LZ4HC_reverseCountPattern(const BYTE* ip, const BYTE* const iLow, U32 pattern) -{ - const BYTE* const iStart = ip; - - while (likely(ip >= iLow+4)) { - if (LZ4_read32(ip-4) != pattern) break; - ip -= 4; - } - { const BYTE* bytePtr = (const BYTE*)(&pattern) + 3; /* works for any endianess */ - while (likely(ip>iLow)) { - if (ip[-1] != *bytePtr) break; - ip--; bytePtr--; - } } - return (unsigned)(iStart - ip); -} - -/* LZ4HC_protectDictEnd() : - * Checks if the match is in the last 3 bytes of the dictionary, so reading the - * 4 byte MINMATCH would overflow. - * @returns true if the match index is okay. - */ -static int LZ4HC_protectDictEnd(U32 const dictLimit, U32 const matchIndex) -{ - return ((U32)((dictLimit - 1) - matchIndex) >= 3); -} - -typedef enum { rep_untested, rep_not, rep_confirmed } repeat_state_e; -typedef enum { favorCompressionRatio=0, favorDecompressionSpeed } HCfavor_e; - -LZ4_FORCE_INLINE int -LZ4HC_InsertAndGetWiderMatch ( - LZ4HC_CCtx_internal* hc4, - const BYTE* const ip, - const BYTE* const iLowLimit, - const BYTE* const iHighLimit, - int longest, - const BYTE** matchpos, - const BYTE** startpos, - const int maxNbAttempts, - const int patternAnalysis, - const int chainSwap, - const dictCtx_directive dict, - const HCfavor_e favorDecSpeed) -{ - U16* const chainTable = hc4->chainTable; - U32* const HashTable = hc4->hashTable; - const LZ4HC_CCtx_internal * const dictCtx = hc4->dictCtx; - const BYTE* const base = hc4->base; - const U32 dictLimit = hc4->dictLimit; - const BYTE* const lowPrefixPtr = base + dictLimit; - const U32 ipIndex = (U32)(ip - base); - const U32 lowestMatchIndex = (hc4->lowLimit + (LZ4_DISTANCE_MAX + 1) > ipIndex) ? hc4->lowLimit : ipIndex - LZ4_DISTANCE_MAX; - const BYTE* const dictBase = hc4->dictBase; - int const lookBackLength = (int)(ip-iLowLimit); - int nbAttempts = maxNbAttempts; - U32 matchChainPos = 0; - U32 const pattern = LZ4_read32(ip); - U32 matchIndex; - repeat_state_e repeat = rep_untested; - size_t srcPatternLength = 0; - - DEBUGLOG(7, "LZ4HC_InsertAndGetWiderMatch"); - /* First Match */ - LZ4HC_Insert(hc4, ip); - matchIndex = HashTable[LZ4HC_hashPtr(ip)]; - DEBUGLOG(7, "First match at index %u / %u (lowestMatchIndex)", - matchIndex, lowestMatchIndex); - - while ((matchIndex>=lowestMatchIndex) && (nbAttempts)) { - int matchLength=0; - nbAttempts--; - assert(matchIndex < ipIndex); - if (favorDecSpeed && (ipIndex - matchIndex < 8)) { - /* do nothing */ - } else if (matchIndex >= dictLimit) { /* within current Prefix */ - const BYTE* const matchPtr = base + matchIndex; - assert(matchPtr >= lowPrefixPtr); - assert(matchPtr < ip); - assert(longest >= 1); - if (LZ4_read16(iLowLimit + longest - 1) == LZ4_read16(matchPtr - lookBackLength + longest - 1)) { - if (LZ4_read32(matchPtr) == pattern) { - int const back = lookBackLength ? LZ4HC_countBack(ip, matchPtr, iLowLimit, lowPrefixPtr) : 0; - matchLength = MINMATCH + (int)LZ4_count(ip+MINMATCH, matchPtr+MINMATCH, iHighLimit); - matchLength -= back; - if (matchLength > longest) { - longest = matchLength; - *matchpos = matchPtr + back; - *startpos = ip + back; - } } } - } else { /* lowestMatchIndex <= matchIndex < dictLimit */ - const BYTE* const matchPtr = dictBase + matchIndex; - if (LZ4_read32(matchPtr) == pattern) { - const BYTE* const dictStart = dictBase + hc4->lowLimit; - int back = 0; - const BYTE* vLimit = ip + (dictLimit - matchIndex); - if (vLimit > iHighLimit) vLimit = iHighLimit; - matchLength = (int)LZ4_count(ip+MINMATCH, matchPtr+MINMATCH, vLimit) + MINMATCH; - if ((ip+matchLength == vLimit) && (vLimit < iHighLimit)) - matchLength += LZ4_count(ip+matchLength, lowPrefixPtr, iHighLimit); - back = lookBackLength ? LZ4HC_countBack(ip, matchPtr, iLowLimit, dictStart) : 0; - matchLength -= back; - if (matchLength > longest) { - longest = matchLength; - *matchpos = base + matchIndex + back; /* virtual pos, relative to ip, to retrieve offset */ - *startpos = ip + back; - } } } - - if (chainSwap && matchLength==longest) { /* better match => select a better chain */ - assert(lookBackLength==0); /* search forward only */ - if (matchIndex + (U32)longest <= ipIndex) { - int const kTrigger = 4; - U32 distanceToNextMatch = 1; - int const end = longest - MINMATCH + 1; - int step = 1; - int accel = 1 << kTrigger; - int pos; - for (pos = 0; pos < end; pos += step) { - U32 const candidateDist = DELTANEXTU16(chainTable, matchIndex + (U32)pos); - step = (accel++ >> kTrigger); - if (candidateDist > distanceToNextMatch) { - distanceToNextMatch = candidateDist; - matchChainPos = (U32)pos; - accel = 1 << kTrigger; - } - } - if (distanceToNextMatch > 1) { - if (distanceToNextMatch > matchIndex) break; /* avoid overflow */ - matchIndex -= distanceToNextMatch; - continue; - } } } - - { U32 const distNextMatch = DELTANEXTU16(chainTable, matchIndex); - if (patternAnalysis && distNextMatch==1 && matchChainPos==0) { - U32 const matchCandidateIdx = matchIndex-1; - /* may be a repeated pattern */ - if (repeat == rep_untested) { - if ( ((pattern & 0xFFFF) == (pattern >> 16)) - & ((pattern & 0xFF) == (pattern >> 24)) ) { - repeat = rep_confirmed; - srcPatternLength = LZ4HC_countPattern(ip+sizeof(pattern), iHighLimit, pattern) + sizeof(pattern); - } else { - repeat = rep_not; - } } - if ( (repeat == rep_confirmed) && (matchCandidateIdx >= lowestMatchIndex) - && LZ4HC_protectDictEnd(dictLimit, matchCandidateIdx) ) { - const int extDict = matchCandidateIdx < dictLimit; - const BYTE* const matchPtr = (extDict ? dictBase : base) + matchCandidateIdx; - if (LZ4_read32(matchPtr) == pattern) { /* good candidate */ - const BYTE* const dictStart = dictBase + hc4->lowLimit; - const BYTE* const iLimit = extDict ? dictBase + dictLimit : iHighLimit; - size_t forwardPatternLength = LZ4HC_countPattern(matchPtr+sizeof(pattern), iLimit, pattern) + sizeof(pattern); - if (extDict && matchPtr + forwardPatternLength == iLimit) { - U32 const rotatedPattern = LZ4HC_rotatePattern(forwardPatternLength, pattern); - forwardPatternLength += LZ4HC_countPattern(lowPrefixPtr, iHighLimit, rotatedPattern); - } - { const BYTE* const lowestMatchPtr = extDict ? dictStart : lowPrefixPtr; - size_t backLength = LZ4HC_reverseCountPattern(matchPtr, lowestMatchPtr, pattern); - size_t currentSegmentLength; - if (!extDict && matchPtr - backLength == lowPrefixPtr && hc4->lowLimit < dictLimit) { - U32 const rotatedPattern = LZ4HC_rotatePattern((U32)(-(int)backLength), pattern); - backLength += LZ4HC_reverseCountPattern(dictBase + dictLimit, dictStart, rotatedPattern); - } - /* Limit backLength not go further than lowestMatchIndex */ - backLength = matchCandidateIdx - MAX(matchCandidateIdx - (U32)backLength, lowestMatchIndex); - assert(matchCandidateIdx - backLength >= lowestMatchIndex); - currentSegmentLength = backLength + forwardPatternLength; - /* Adjust to end of pattern if the source pattern fits, otherwise the beginning of the pattern */ - if ( (currentSegmentLength >= srcPatternLength) /* current pattern segment large enough to contain full srcPatternLength */ - && (forwardPatternLength <= srcPatternLength) ) { /* haven't reached this position yet */ - U32 const newMatchIndex = matchCandidateIdx + (U32)forwardPatternLength - (U32)srcPatternLength; /* best position, full pattern, might be followed by more match */ - if (LZ4HC_protectDictEnd(dictLimit, newMatchIndex)) - matchIndex = newMatchIndex; - else { - /* Can only happen if started in the prefix */ - assert(newMatchIndex >= dictLimit - 3 && newMatchIndex < dictLimit && !extDict); - matchIndex = dictLimit; - } - } else { - U32 const newMatchIndex = matchCandidateIdx - (U32)backLength; /* farthest position in current segment, will find a match of length currentSegmentLength + maybe some back */ - if (!LZ4HC_protectDictEnd(dictLimit, newMatchIndex)) { - assert(newMatchIndex >= dictLimit - 3 && newMatchIndex < dictLimit && !extDict); - matchIndex = dictLimit; - } else { - matchIndex = newMatchIndex; - if (lookBackLength==0) { /* no back possible */ - size_t const maxML = MIN(currentSegmentLength, srcPatternLength); - if ((size_t)longest < maxML) { - assert(base + matchIndex < ip); - if (ip - (base+matchIndex) > LZ4_DISTANCE_MAX) break; - assert(maxML < 2 GB); - longest = (int)maxML; - *matchpos = base + matchIndex; /* virtual pos, relative to ip, to retrieve offset */ - *startpos = ip; - } - { U32 const distToNextPattern = DELTANEXTU16(chainTable, matchIndex); - if (distToNextPattern > matchIndex) break; /* avoid overflow */ - matchIndex -= distToNextPattern; - } } } } } - continue; - } } - } } /* PA optimization */ - - /* follow current chain */ - matchIndex -= DELTANEXTU16(chainTable, matchIndex + matchChainPos); - - } /* while ((matchIndex>=lowestMatchIndex) && (nbAttempts)) */ - - if ( dict == usingDictCtxHc - && nbAttempts - && ipIndex - lowestMatchIndex < LZ4_DISTANCE_MAX) { - size_t const dictEndOffset = (size_t)(dictCtx->end - dictCtx->base); - U32 dictMatchIndex = dictCtx->hashTable[LZ4HC_hashPtr(ip)]; - assert(dictEndOffset <= 1 GB); - matchIndex = dictMatchIndex + lowestMatchIndex - (U32)dictEndOffset; - while (ipIndex - matchIndex <= LZ4_DISTANCE_MAX && nbAttempts--) { - const BYTE* const matchPtr = dictCtx->base + dictMatchIndex; - - if (LZ4_read32(matchPtr) == pattern) { - int mlt; - int back = 0; - const BYTE* vLimit = ip + (dictEndOffset - dictMatchIndex); - if (vLimit > iHighLimit) vLimit = iHighLimit; - mlt = (int)LZ4_count(ip+MINMATCH, matchPtr+MINMATCH, vLimit) + MINMATCH; - back = lookBackLength ? LZ4HC_countBack(ip, matchPtr, iLowLimit, dictCtx->base + dictCtx->dictLimit) : 0; - mlt -= back; - if (mlt > longest) { - longest = mlt; - *matchpos = base + matchIndex + back; - *startpos = ip + back; - } } - - { U32 const nextOffset = DELTANEXTU16(dictCtx->chainTable, dictMatchIndex); - dictMatchIndex -= nextOffset; - matchIndex -= nextOffset; - } } } - - return longest; -} - -LZ4_FORCE_INLINE -int LZ4HC_InsertAndFindBestMatch(LZ4HC_CCtx_internal* const hc4, /* Index table will be updated */ - const BYTE* const ip, const BYTE* const iLimit, - const BYTE** matchpos, - const int maxNbAttempts, - const int patternAnalysis, - const dictCtx_directive dict) -{ - const BYTE* uselessPtr = ip; - /* note : LZ4HC_InsertAndGetWiderMatch() is able to modify the starting position of a match (*startpos), - * but this won't be the case here, as we define iLowLimit==ip, - * so LZ4HC_InsertAndGetWiderMatch() won't be allowed to search past ip */ - return LZ4HC_InsertAndGetWiderMatch(hc4, ip, ip, iLimit, MINMATCH-1, matchpos, &uselessPtr, maxNbAttempts, patternAnalysis, 0 /*chainSwap*/, dict, favorCompressionRatio); -} - -/* LZ4HC_encodeSequence() : - * @return : 0 if ok, - * 1 if buffer issue detected */ -LZ4_FORCE_INLINE int LZ4HC_encodeSequence ( - const BYTE** ip, - BYTE** op, - const BYTE** anchor, - int matchLength, - const BYTE* const match, - limitedOutput_directive limit, - BYTE* oend) -{ - size_t length; - BYTE* const token = (*op)++; - -#if defined(LZ4_DEBUG) && (LZ4_DEBUG >= 6) - static const BYTE* start = NULL; - static U32 totalCost = 0; - U32 const pos = (start==NULL) ? 0 : (U32)(*anchor - start); - U32 const ll = (U32)(*ip - *anchor); - U32 const llAdd = (ll>=15) ? ((ll-15) / 255) + 1 : 0; - U32 const mlAdd = (matchLength>=19) ? ((matchLength-19) / 255) + 1 : 0; - U32 const cost = 1 + llAdd + ll + 2 + mlAdd; - if (start==NULL) start = *anchor; /* only works for single segment */ - /* g_debuglog_enable = (pos >= 2228) & (pos <= 2262); */ - DEBUGLOG(6, "pos:%7u -- literals:%3u, match:%4i, offset:%5u, cost:%3u + %u", - pos, - (U32)(*ip - *anchor), matchLength, (U32)(*ip-match), - cost, totalCost); - totalCost += cost; -#endif - - /* Encode Literal length */ - length = (size_t)(*ip - *anchor); - if ((limit) && ((*op + (length / 255) + length + (2 + 1 + LASTLITERALS)) > oend)) return 1; /* Check output limit */ - if (length >= RUN_MASK) { - size_t len = length - RUN_MASK; - *token = (RUN_MASK << ML_BITS); - for(; len >= 255 ; len -= 255) *(*op)++ = 255; - *(*op)++ = (BYTE)len; - } else { - *token = (BYTE)(length << ML_BITS); - } - - /* Copy Literals */ - LZ4_wildCopy8(*op, *anchor, (*op) + length); - *op += length; - - /* Encode Offset */ - assert( (*ip - match) <= LZ4_DISTANCE_MAX ); /* note : consider providing offset as a value, rather than as a pointer difference */ - LZ4_writeLE16(*op, (U16)(*ip-match)); *op += 2; - - /* Encode MatchLength */ - assert(matchLength >= MINMATCH); - length = (size_t)matchLength - MINMATCH; - if ((limit) && (*op + (length / 255) + (1 + LASTLITERALS) > oend)) return 1; /* Check output limit */ - if (length >= ML_MASK) { - *token += ML_MASK; - length -= ML_MASK; - for(; length >= 510 ; length -= 510) { *(*op)++ = 255; *(*op)++ = 255; } - if (length >= 255) { length -= 255; *(*op)++ = 255; } - *(*op)++ = (BYTE)length; - } else { - *token += (BYTE)(length); - } - - /* Prepare next loop */ - *ip += matchLength; - *anchor = *ip; - - return 0; -} - -LZ4_FORCE_INLINE int LZ4HC_compress_hashChain ( - LZ4HC_CCtx_internal* const ctx, - const char* const source, - char* const dest, - int* srcSizePtr, - int const maxOutputSize, - unsigned maxNbAttempts, - const limitedOutput_directive limit, - const dictCtx_directive dict - ) -{ - const int inputSize = *srcSizePtr; - const int patternAnalysis = (maxNbAttempts > 128); /* levels 9+ */ - - const BYTE* ip = (const BYTE*) source; - const BYTE* anchor = ip; - const BYTE* const iend = ip + inputSize; - const BYTE* const mflimit = iend - MFLIMIT; - const BYTE* const matchlimit = (iend - LASTLITERALS); - - BYTE* optr = (BYTE*) dest; - BYTE* op = (BYTE*) dest; - BYTE* oend = op + maxOutputSize; - - int ml0, ml, ml2, ml3; - const BYTE* start0; - const BYTE* ref0; - const BYTE* ref = NULL; - const BYTE* start2 = NULL; - const BYTE* ref2 = NULL; - const BYTE* start3 = NULL; - const BYTE* ref3 = NULL; - - /* init */ - *srcSizePtr = 0; - if (limit == fillOutput) oend -= LASTLITERALS; /* Hack for support LZ4 format restriction */ - if (inputSize < LZ4_minLength) goto _last_literals; /* Input too small, no compression (all literals) */ - - /* Main Loop */ - while (ip <= mflimit) { - ml = LZ4HC_InsertAndFindBestMatch(ctx, ip, matchlimit, &ref, maxNbAttempts, patternAnalysis, dict); - if (ml<MINMATCH) { ip++; continue; } - - /* saved, in case we would skip too much */ - start0 = ip; ref0 = ref; ml0 = ml; - -_Search2: - if (ip+ml <= mflimit) { - ml2 = LZ4HC_InsertAndGetWiderMatch(ctx, - ip + ml - 2, ip + 0, matchlimit, ml, &ref2, &start2, - maxNbAttempts, patternAnalysis, 0, dict, favorCompressionRatio); - } else { - ml2 = ml; - } - - if (ml2 == ml) { /* No better match => encode ML1 */ - optr = op; - if (LZ4HC_encodeSequence(UPDATABLE(ip, op, anchor), ml, ref, limit, oend)) goto _dest_overflow; - continue; - } - - if (start0 < ip) { /* first match was skipped at least once */ - if (start2 < ip + ml0) { /* squeezing ML1 between ML0(original ML1) and ML2 */ - ip = start0; ref = ref0; ml = ml0; /* restore initial ML1 */ - } } - - /* Here, start0==ip */ - if ((start2 - ip) < 3) { /* First Match too small : removed */ - ml = ml2; - ip = start2; - ref =ref2; - goto _Search2; - } - -_Search3: - /* At this stage, we have : - * ml2 > ml1, and - * ip1+3 <= ip2 (usually < ip1+ml1) */ - if ((start2 - ip) < OPTIMAL_ML) { - int correction; - int new_ml = ml; - if (new_ml > OPTIMAL_ML) new_ml = OPTIMAL_ML; - if (ip+new_ml > start2 + ml2 - MINMATCH) new_ml = (int)(start2 - ip) + ml2 - MINMATCH; - correction = new_ml - (int)(start2 - ip); - if (correction > 0) { - start2 += correction; - ref2 += correction; - ml2 -= correction; - } - } - /* Now, we have start2 = ip+new_ml, with new_ml = min(ml, OPTIMAL_ML=18) */ - - if (start2 + ml2 <= mflimit) { - ml3 = LZ4HC_InsertAndGetWiderMatch(ctx, - start2 + ml2 - 3, start2, matchlimit, ml2, &ref3, &start3, - maxNbAttempts, patternAnalysis, 0, dict, favorCompressionRatio); - } else { - ml3 = ml2; - } - - if (ml3 == ml2) { /* No better match => encode ML1 and ML2 */ - /* ip & ref are known; Now for ml */ - if (start2 < ip+ml) ml = (int)(start2 - ip); - /* Now, encode 2 sequences */ - optr = op; - if (LZ4HC_encodeSequence(UPDATABLE(ip, op, anchor), ml, ref, limit, oend)) goto _dest_overflow; - ip = start2; - optr = op; - if (LZ4HC_encodeSequence(UPDATABLE(ip, op, anchor), ml2, ref2, limit, oend)) goto _dest_overflow; - continue; - } - - if (start3 < ip+ml+3) { /* Not enough space for match 2 : remove it */ - if (start3 >= (ip+ml)) { /* can write Seq1 immediately ==> Seq2 is removed, so Seq3 becomes Seq1 */ - if (start2 < ip+ml) { - int correction = (int)(ip+ml - start2); - start2 += correction; - ref2 += correction; - ml2 -= correction; - if (ml2 < MINMATCH) { - start2 = start3; - ref2 = ref3; - ml2 = ml3; - } - } - - optr = op; - if (LZ4HC_encodeSequence(UPDATABLE(ip, op, anchor), ml, ref, limit, oend)) goto _dest_overflow; - ip = start3; - ref = ref3; - ml = ml3; - - start0 = start2; - ref0 = ref2; - ml0 = ml2; - goto _Search2; - } - - start2 = start3; - ref2 = ref3; - ml2 = ml3; - goto _Search3; - } - - /* - * OK, now we have 3 ascending matches; - * let's write the first one ML1. - * ip & ref are known; Now decide ml. - */ - if (start2 < ip+ml) { - if ((start2 - ip) < OPTIMAL_ML) { - int correction; - if (ml > OPTIMAL_ML) ml = OPTIMAL_ML; - if (ip + ml > start2 + ml2 - MINMATCH) ml = (int)(start2 - ip) + ml2 - MINMATCH; - correction = ml - (int)(start2 - ip); - if (correction > 0) { - start2 += correction; - ref2 += correction; - ml2 -= correction; - } - } else { - ml = (int)(start2 - ip); - } - } - optr = op; - if (LZ4HC_encodeSequence(UPDATABLE(ip, op, anchor), ml, ref, limit, oend)) goto _dest_overflow; - - /* ML2 becomes ML1 */ - ip = start2; ref = ref2; ml = ml2; - - /* ML3 becomes ML2 */ - start2 = start3; ref2 = ref3; ml2 = ml3; - - /* let's find a new ML3 */ - goto _Search3; - } - -_last_literals: - /* Encode Last Literals */ - { size_t lastRunSize = (size_t)(iend - anchor); /* literals */ - size_t litLength = (lastRunSize + 255 - RUN_MASK) / 255; - size_t const totalSize = 1 + litLength + lastRunSize; - if (limit == fillOutput) oend += LASTLITERALS; /* restore correct value */ - if (limit && (op + totalSize > oend)) { - if (limit == limitedOutput) return 0; /* Check output limit */ - /* adapt lastRunSize to fill 'dest' */ - lastRunSize = (size_t)(oend - op) - 1; - litLength = (lastRunSize + 255 - RUN_MASK) / 255; - lastRunSize -= litLength; - } - ip = anchor + lastRunSize; - - if (lastRunSize >= RUN_MASK) { - size_t accumulator = lastRunSize - RUN_MASK; - *op++ = (RUN_MASK << ML_BITS); - for(; accumulator >= 255 ; accumulator -= 255) *op++ = 255; - *op++ = (BYTE) accumulator; - } else { - *op++ = (BYTE)(lastRunSize << ML_BITS); - } - memcpy(op, anchor, lastRunSize); - op += lastRunSize; - } - - /* End */ - *srcSizePtr = (int) (((const char*)ip) - source); - return (int) (((char*)op)-dest); - -_dest_overflow: - if (limit == fillOutput) { - op = optr; /* restore correct out pointer */ - goto _last_literals; - } - return 0; -} - - -static int LZ4HC_compress_optimal( LZ4HC_CCtx_internal* ctx, - const char* const source, char* dst, - int* srcSizePtr, int dstCapacity, - int const nbSearches, size_t sufficient_len, - const limitedOutput_directive limit, int const fullUpdate, - const dictCtx_directive dict, - HCfavor_e favorDecSpeed); - - -LZ4_FORCE_INLINE int LZ4HC_compress_generic_internal ( - LZ4HC_CCtx_internal* const ctx, - const char* const src, - char* const dst, - int* const srcSizePtr, - int const dstCapacity, - int cLevel, - const limitedOutput_directive limit, - const dictCtx_directive dict - ) -{ - typedef enum { lz4hc, lz4opt } lz4hc_strat_e; - typedef struct { - lz4hc_strat_e strat; - U32 nbSearches; - U32 targetLength; - } cParams_t; - static const cParams_t clTable[LZ4HC_CLEVEL_MAX+1] = { - { lz4hc, 2, 16 }, /* 0, unused */ - { lz4hc, 2, 16 }, /* 1, unused */ - { lz4hc, 2, 16 }, /* 2, unused */ - { lz4hc, 4, 16 }, /* 3 */ - { lz4hc, 8, 16 }, /* 4 */ - { lz4hc, 16, 16 }, /* 5 */ - { lz4hc, 32, 16 }, /* 6 */ - { lz4hc, 64, 16 }, /* 7 */ - { lz4hc, 128, 16 }, /* 8 */ - { lz4hc, 256, 16 }, /* 9 */ - { lz4opt, 96, 64 }, /*10==LZ4HC_CLEVEL_OPT_MIN*/ - { lz4opt, 512,128 }, /*11 */ - { lz4opt,16384,LZ4_OPT_NUM }, /* 12==LZ4HC_CLEVEL_MAX */ - }; - - DEBUGLOG(4, "LZ4HC_compress_generic(ctx=%p, src=%p, srcSize=%d)", ctx, src, *srcSizePtr); - - if (limit == fillOutput && dstCapacity < 1) return 0; /* Impossible to store anything */ - if ((U32)*srcSizePtr > (U32)LZ4_MAX_INPUT_SIZE) return 0; /* Unsupported input size (too large or negative) */ - - ctx->end += *srcSizePtr; - if (cLevel < 1) cLevel = LZ4HC_CLEVEL_DEFAULT; /* note : convention is different from lz4frame, maybe something to review */ - cLevel = MIN(LZ4HC_CLEVEL_MAX, cLevel); - { cParams_t const cParam = clTable[cLevel]; - HCfavor_e const favor = ctx->favorDecSpeed ? favorDecompressionSpeed : favorCompressionRatio; - int result; - - if (cParam.strat == lz4hc) { - result = LZ4HC_compress_hashChain(ctx, - src, dst, srcSizePtr, dstCapacity, - cParam.nbSearches, limit, dict); - } else { - assert(cParam.strat == lz4opt); - result = LZ4HC_compress_optimal(ctx, - src, dst, srcSizePtr, dstCapacity, - (int)cParam.nbSearches, cParam.targetLength, limit, - cLevel == LZ4HC_CLEVEL_MAX, /* ultra mode */ - dict, favor); - } - if (result <= 0) ctx->dirty = 1; - return result; - } -} - -static void LZ4HC_setExternalDict(LZ4HC_CCtx_internal* ctxPtr, const BYTE* newBlock); - -static int -LZ4HC_compress_generic_noDictCtx ( - LZ4HC_CCtx_internal* const ctx, - const char* const src, - char* const dst, - int* const srcSizePtr, - int const dstCapacity, - int cLevel, - limitedOutput_directive limit - ) -{ - assert(ctx->dictCtx == NULL); - return LZ4HC_compress_generic_internal(ctx, src, dst, srcSizePtr, dstCapacity, cLevel, limit, noDictCtx); -} - -static int -LZ4HC_compress_generic_dictCtx ( - LZ4HC_CCtx_internal* const ctx, - const char* const src, - char* const dst, - int* const srcSizePtr, - int const dstCapacity, - int cLevel, - limitedOutput_directive limit - ) -{ - const size_t position = (size_t)(ctx->end - ctx->base) - ctx->lowLimit; - assert(ctx->dictCtx != NULL); - if (position >= 64 KB) { - ctx->dictCtx = NULL; - return LZ4HC_compress_generic_noDictCtx(ctx, src, dst, srcSizePtr, dstCapacity, cLevel, limit); - } else if (position == 0 && *srcSizePtr > 4 KB) { - memcpy(ctx, ctx->dictCtx, sizeof(LZ4HC_CCtx_internal)); - LZ4HC_setExternalDict(ctx, (const BYTE *)src); - ctx->compressionLevel = (short)cLevel; - return LZ4HC_compress_generic_noDictCtx(ctx, src, dst, srcSizePtr, dstCapacity, cLevel, limit); - } else { - return LZ4HC_compress_generic_internal(ctx, src, dst, srcSizePtr, dstCapacity, cLevel, limit, usingDictCtxHc); - } -} - -static int -LZ4HC_compress_generic ( - LZ4HC_CCtx_internal* const ctx, - const char* const src, - char* const dst, - int* const srcSizePtr, - int const dstCapacity, - int cLevel, - limitedOutput_directive limit - ) -{ - if (ctx->dictCtx == NULL) { - return LZ4HC_compress_generic_noDictCtx(ctx, src, dst, srcSizePtr, dstCapacity, cLevel, limit); - } else { - return LZ4HC_compress_generic_dictCtx(ctx, src, dst, srcSizePtr, dstCapacity, cLevel, limit); - } -} - - -int LZ4_sizeofStateHC(void) { return (int)sizeof(LZ4_streamHC_t); } - -#ifndef _MSC_VER /* for some reason, Visual fails the aligment test on 32-bit x86 : - * it reports an aligment of 8-bytes, - * while actually aligning LZ4_streamHC_t on 4 bytes. */ -static size_t LZ4_streamHC_t_alignment(void) -{ - struct { char c; LZ4_streamHC_t t; } t_a; - return sizeof(t_a) - sizeof(t_a.t); -} -#endif - -/* state is presumed correctly initialized, - * in which case its size and alignment have already been validate */ -static int LZ4_compress_HC_extStateHC_fastReset (void* state, const char* src, char* dst, int srcSize, - int dstCapacity, int compressionLevel) -{ - LZ4HC_CCtx_internal* const ctx = &((LZ4_streamHC_t*)state)->internal_donotuse; -#ifndef _MSC_VER /* for some reason, Visual fails the aligment test on 32-bit x86 : - * it reports an aligment of 8-bytes, - * while actually aligning LZ4_streamHC_t on 4 bytes. */ - assert(((size_t)state & (LZ4_streamHC_t_alignment() - 1)) == 0); /* check alignment */ -#endif - if (((size_t)(state)&(sizeof(void*)-1)) != 0) return 0; /* Error : state is not aligned for pointers (32 or 64 bits) */ - LZ4_resetStreamHC_fast((LZ4_streamHC_t*)state, compressionLevel); - LZ4HC_init_internal (ctx, (const BYTE*)src); - if (dstCapacity < LZ4_compressBound(srcSize)) - return LZ4HC_compress_generic (ctx, src, dst, &srcSize, dstCapacity, compressionLevel, limitedOutput); - else - return LZ4HC_compress_generic (ctx, src, dst, &srcSize, dstCapacity, compressionLevel, notLimited); -} - -int LZ4_compress_HC_extStateHC (void* state, const char* src, char* dst, int srcSize, int dstCapacity, int compressionLevel) -{ - LZ4_streamHC_t* const ctx = LZ4_initStreamHC(state, sizeof(*ctx)); - if (ctx==NULL) return 0; /* init failure */ - return LZ4_compress_HC_extStateHC_fastReset(state, src, dst, srcSize, dstCapacity, compressionLevel); -} - -int LZ4_compress_HC(const char* src, char* dst, int srcSize, int dstCapacity, int compressionLevel) -{ -#if defined(LZ4HC_HEAPMODE) && LZ4HC_HEAPMODE==1 - LZ4_streamHC_t* const statePtr = (LZ4_streamHC_t*)ALLOC(sizeof(LZ4_streamHC_t)); -#else - LZ4_streamHC_t state; - LZ4_streamHC_t* const statePtr = &state; -#endif - int const cSize = LZ4_compress_HC_extStateHC(statePtr, src, dst, srcSize, dstCapacity, compressionLevel); -#if defined(LZ4HC_HEAPMODE) && LZ4HC_HEAPMODE==1 - FREEMEM(statePtr); -#endif - return cSize; -} - -/* state is presumed sized correctly (>= sizeof(LZ4_streamHC_t)) */ -int LZ4_compress_HC_destSize(void* state, const char* source, char* dest, int* sourceSizePtr, int targetDestSize, int cLevel) -{ - LZ4_streamHC_t* const ctx = LZ4_initStreamHC(state, sizeof(*ctx)); - if (ctx==NULL) return 0; /* init failure */ - LZ4HC_init_internal(&ctx->internal_donotuse, (const BYTE*) source); - LZ4_setCompressionLevel(ctx, cLevel); - return LZ4HC_compress_generic(&ctx->internal_donotuse, source, dest, sourceSizePtr, targetDestSize, cLevel, fillOutput); -} - - - -/************************************** -* Streaming Functions -**************************************/ - -LZ4_streamHC_t* LZ4_initStreamHC (void* buffer, size_t size) -{ - LZ4_streamHC_t* const LZ4_streamHCPtr = (LZ4_streamHC_t*)buffer; - if (buffer == NULL) return NULL; - if (size < sizeof(LZ4_streamHC_t)) return NULL; -#ifndef _MSC_VER /* for some reason, Visual fails the aligment test on 32-bit x86 : - * it reports an aligment of 8-bytes, - * while actually aligning LZ4_streamHC_t on 4 bytes. */ - if (((size_t)buffer) & (LZ4_streamHC_t_alignment() - 1)) return NULL; /* alignment check */ -#endif - /* if compilation fails here, LZ4_STREAMHCSIZE must be increased */ - LZ4_STATIC_ASSERT(sizeof(LZ4HC_CCtx_internal) <= LZ4_STREAMHCSIZE); - DEBUGLOG(4, "LZ4_initStreamHC(%p, %u)", LZ4_streamHCPtr, (unsigned)size); - /* end-base will trigger a clearTable on starting compression */ - LZ4_streamHCPtr->internal_donotuse.end = (const BYTE *)(ptrdiff_t)-1; - LZ4_streamHCPtr->internal_donotuse.base = NULL; - LZ4_streamHCPtr->internal_donotuse.dictCtx = NULL; - LZ4_streamHCPtr->internal_donotuse.favorDecSpeed = 0; - LZ4_streamHCPtr->internal_donotuse.dirty = 0; - LZ4_setCompressionLevel(LZ4_streamHCPtr, LZ4HC_CLEVEL_DEFAULT); - return LZ4_streamHCPtr; -} - -/* just a stub */ -void LZ4_resetStreamHC_fast (LZ4_streamHC_t* LZ4_streamHCPtr, int compressionLevel) -{ - DEBUGLOG(4, "LZ4_resetStreamHC_fast(%p, %d)", LZ4_streamHCPtr, compressionLevel); - if (LZ4_streamHCPtr->internal_donotuse.dirty) { - LZ4_initStreamHC(LZ4_streamHCPtr, sizeof(*LZ4_streamHCPtr)); - } else { - /* preserve end - base : can trigger clearTable's threshold */ - LZ4_streamHCPtr->internal_donotuse.end -= (uptrval)LZ4_streamHCPtr->internal_donotuse.base; - LZ4_streamHCPtr->internal_donotuse.base = NULL; - LZ4_streamHCPtr->internal_donotuse.dictCtx = NULL; - } - LZ4_setCompressionLevel(LZ4_streamHCPtr, compressionLevel); -} - -void LZ4_setCompressionLevel(LZ4_streamHC_t* LZ4_streamHCPtr, int compressionLevel) -{ - DEBUGLOG(5, "LZ4_setCompressionLevel(%p, %d)", LZ4_streamHCPtr, compressionLevel); - if (compressionLevel < 1) compressionLevel = LZ4HC_CLEVEL_DEFAULT; - if (compressionLevel > LZ4HC_CLEVEL_MAX) compressionLevel = LZ4HC_CLEVEL_MAX; - LZ4_streamHCPtr->internal_donotuse.compressionLevel = (short)compressionLevel; -} - -/* compression */ - -static void LZ4HC_setExternalDict(LZ4HC_CCtx_internal* ctxPtr, const BYTE* newBlock) -{ - DEBUGLOG(4, "LZ4HC_setExternalDict(%p, %p)", ctxPtr, newBlock); - if (ctxPtr->end >= ctxPtr->base + ctxPtr->dictLimit + 4) - LZ4HC_Insert (ctxPtr, ctxPtr->end-3); /* Referencing remaining dictionary content */ - - /* Only one memory segment for extDict, so any previous extDict is lost at this stage */ - ctxPtr->lowLimit = ctxPtr->dictLimit; - ctxPtr->dictLimit = (U32)(ctxPtr->end - ctxPtr->base); - ctxPtr->dictBase = ctxPtr->base; - ctxPtr->base = newBlock - ctxPtr->dictLimit; - ctxPtr->end = newBlock; - ctxPtr->nextToUpdate = ctxPtr->dictLimit; /* match referencing will resume from there */ - - /* cannot reference an extDict and a dictCtx at the same time */ - ctxPtr->dictCtx = NULL; -} - -/* ================================================ - * LZ4 Optimal parser (levels [LZ4HC_CLEVEL_OPT_MIN - LZ4HC_CLEVEL_MAX]) - * ===============================================*/ -typedef struct { - int price; - int off; - int mlen; - int litlen; -} LZ4HC_optimal_t; - -/* price in bytes */ -LZ4_FORCE_INLINE int LZ4HC_literalsPrice(int const litlen) -{ - int price = litlen; - assert(litlen >= 0); - if (litlen >= (int)RUN_MASK) - price += 1 + ((litlen-(int)RUN_MASK) / 255); - return price; -} - - -/* requires mlen >= MINMATCH */ -LZ4_FORCE_INLINE int LZ4HC_sequencePrice(int litlen, int mlen) -{ - int price = 1 + 2 ; /* token + 16-bit offset */ - assert(litlen >= 0); - assert(mlen >= MINMATCH); - - price += LZ4HC_literalsPrice(litlen); - - if (mlen >= (int)(ML_MASK+MINMATCH)) - price += 1 + ((mlen-(int)(ML_MASK+MINMATCH)) / 255); - - return price; -} - - -typedef struct { - int off; - int len; -} LZ4HC_match_t; - -LZ4_FORCE_INLINE LZ4HC_match_t -LZ4HC_FindLongerMatch(LZ4HC_CCtx_internal* const ctx, - const BYTE* ip, const BYTE* const iHighLimit, - int minLen, int nbSearches, - const dictCtx_directive dict, - const HCfavor_e favorDecSpeed) -{ - LZ4HC_match_t match = { 0 , 0 }; - const BYTE* matchPtr = NULL; - /* note : LZ4HC_InsertAndGetWiderMatch() is able to modify the starting position of a match (*startpos), - * but this won't be the case here, as we define iLowLimit==ip, - * so LZ4HC_InsertAndGetWiderMatch() won't be allowed to search past ip */ - int matchLength = LZ4HC_InsertAndGetWiderMatch(ctx, ip, ip, iHighLimit, minLen, &matchPtr, &ip, nbSearches, 1 /*patternAnalysis*/, 1 /*chainSwap*/, dict, favorDecSpeed); - if (matchLength <= minLen) return match; - if (favorDecSpeed) { - if ((matchLength>18) & (matchLength<=36)) matchLength=18; /* favor shortcut */ - } - match.len = matchLength; - match.off = (int)(ip-matchPtr); - return match; -} - - -static int LZ4HC_compress_optimal ( LZ4HC_CCtx_internal* ctx, - const char* const source, - char* dst, - int* srcSizePtr, - int dstCapacity, - int const nbSearches, - size_t sufficient_len, - const limitedOutput_directive limit, - int const fullUpdate, - const dictCtx_directive dict, - const HCfavor_e favorDecSpeed) -{ -#define TRAILING_LITERALS 3 - LZ4HC_optimal_t opt[LZ4_OPT_NUM + TRAILING_LITERALS]; /* ~64 KB, which is a bit large for stack... */ - - const BYTE* ip = (const BYTE*) source; - const BYTE* anchor = ip; - const BYTE* const iend = ip + *srcSizePtr; - const BYTE* const mflimit = iend - MFLIMIT; - const BYTE* const matchlimit = iend - LASTLITERALS; - BYTE* op = (BYTE*) dst; - BYTE* opSaved = (BYTE*) dst; - BYTE* oend = op + dstCapacity; - - /* init */ - DEBUGLOG(5, "LZ4HC_compress_optimal(dst=%p, dstCapa=%u)", dst, (unsigned)dstCapacity); - *srcSizePtr = 0; - if (limit == fillOutput) oend -= LASTLITERALS; /* Hack for support LZ4 format restriction */ - if (sufficient_len >= LZ4_OPT_NUM) sufficient_len = LZ4_OPT_NUM-1; - - /* Main Loop */ - assert(ip - anchor < LZ4_MAX_INPUT_SIZE); - while (ip <= mflimit) { - int const llen = (int)(ip - anchor); - int best_mlen, best_off; - int cur, last_match_pos = 0; - - LZ4HC_match_t const firstMatch = LZ4HC_FindLongerMatch(ctx, ip, matchlimit, MINMATCH-1, nbSearches, dict, favorDecSpeed); - if (firstMatch.len==0) { ip++; continue; } - - if ((size_t)firstMatch.len > sufficient_len) { - /* good enough solution : immediate encoding */ - int const firstML = firstMatch.len; - const BYTE* const matchPos = ip - firstMatch.off; - opSaved = op; - if ( LZ4HC_encodeSequence(UPDATABLE(ip, op, anchor), firstML, matchPos, limit, oend) ) /* updates ip, op and anchor */ - goto _dest_overflow; - continue; - } - - /* set prices for first positions (literals) */ - { int rPos; - for (rPos = 0 ; rPos < MINMATCH ; rPos++) { - int const cost = LZ4HC_literalsPrice(llen + rPos); - opt[rPos].mlen = 1; - opt[rPos].off = 0; - opt[rPos].litlen = llen + rPos; - opt[rPos].price = cost; - DEBUGLOG(7, "rPos:%3i => price:%3i (litlen=%i) -- initial setup", - rPos, cost, opt[rPos].litlen); - } } - /* set prices using initial match */ - { int mlen = MINMATCH; - int const matchML = firstMatch.len; /* necessarily < sufficient_len < LZ4_OPT_NUM */ - int const offset = firstMatch.off; - assert(matchML < LZ4_OPT_NUM); - for ( ; mlen <= matchML ; mlen++) { - int const cost = LZ4HC_sequencePrice(llen, mlen); - opt[mlen].mlen = mlen; - opt[mlen].off = offset; - opt[mlen].litlen = llen; - opt[mlen].price = cost; - DEBUGLOG(7, "rPos:%3i => price:%3i (matchlen=%i) -- initial setup", - mlen, cost, mlen); - } } - last_match_pos = firstMatch.len; - { int addLit; - for (addLit = 1; addLit <= TRAILING_LITERALS; addLit ++) { - opt[last_match_pos+addLit].mlen = 1; /* literal */ - opt[last_match_pos+addLit].off = 0; - opt[last_match_pos+addLit].litlen = addLit; - opt[last_match_pos+addLit].price = opt[last_match_pos].price + LZ4HC_literalsPrice(addLit); - DEBUGLOG(7, "rPos:%3i => price:%3i (litlen=%i) -- initial setup", - last_match_pos+addLit, opt[last_match_pos+addLit].price, addLit); - } } - - /* check further positions */ - for (cur = 1; cur < last_match_pos; cur++) { - const BYTE* const curPtr = ip + cur; - LZ4HC_match_t newMatch; - - if (curPtr > mflimit) break; - DEBUGLOG(7, "rPos:%u[%u] vs [%u]%u", - cur, opt[cur].price, opt[cur+1].price, cur+1); - if (fullUpdate) { - /* not useful to search here if next position has same (or lower) cost */ - if ( (opt[cur+1].price <= opt[cur].price) - /* in some cases, next position has same cost, but cost rises sharply after, so a small match would still be beneficial */ - && (opt[cur+MINMATCH].price < opt[cur].price + 3/*min seq price*/) ) - continue; - } else { - /* not useful to search here if next position has same (or lower) cost */ - if (opt[cur+1].price <= opt[cur].price) continue; - } - - DEBUGLOG(7, "search at rPos:%u", cur); - if (fullUpdate) - newMatch = LZ4HC_FindLongerMatch(ctx, curPtr, matchlimit, MINMATCH-1, nbSearches, dict, favorDecSpeed); - else - /* only test matches of minimum length; slightly faster, but misses a few bytes */ - newMatch = LZ4HC_FindLongerMatch(ctx, curPtr, matchlimit, last_match_pos - cur, nbSearches, dict, favorDecSpeed); - if (!newMatch.len) continue; - - if ( ((size_t)newMatch.len > sufficient_len) - || (newMatch.len + cur >= LZ4_OPT_NUM) ) { - /* immediate encoding */ - best_mlen = newMatch.len; - best_off = newMatch.off; - last_match_pos = cur + 1; - goto encode; - } - - /* before match : set price with literals at beginning */ - { int const baseLitlen = opt[cur].litlen; - int litlen; - for (litlen = 1; litlen < MINMATCH; litlen++) { - int const price = opt[cur].price - LZ4HC_literalsPrice(baseLitlen) + LZ4HC_literalsPrice(baseLitlen+litlen); - int const pos = cur + litlen; - if (price < opt[pos].price) { - opt[pos].mlen = 1; /* literal */ - opt[pos].off = 0; - opt[pos].litlen = baseLitlen+litlen; - opt[pos].price = price; - DEBUGLOG(7, "rPos:%3i => price:%3i (litlen=%i)", - pos, price, opt[pos].litlen); - } } } - - /* set prices using match at position = cur */ - { int const matchML = newMatch.len; - int ml = MINMATCH; - - assert(cur + newMatch.len < LZ4_OPT_NUM); - for ( ; ml <= matchML ; ml++) { - int const pos = cur + ml; - int const offset = newMatch.off; - int price; - int ll; - DEBUGLOG(7, "testing price rPos %i (last_match_pos=%i)", - pos, last_match_pos); - if (opt[cur].mlen == 1) { - ll = opt[cur].litlen; - price = ((cur > ll) ? opt[cur - ll].price : 0) - + LZ4HC_sequencePrice(ll, ml); - } else { - ll = 0; - price = opt[cur].price + LZ4HC_sequencePrice(0, ml); - } - - assert((U32)favorDecSpeed <= 1); - if (pos > last_match_pos+TRAILING_LITERALS - || price <= opt[pos].price - (int)favorDecSpeed) { - DEBUGLOG(7, "rPos:%3i => price:%3i (matchlen=%i)", - pos, price, ml); - assert(pos < LZ4_OPT_NUM); - if ( (ml == matchML) /* last pos of last match */ - && (last_match_pos < pos) ) - last_match_pos = pos; - opt[pos].mlen = ml; - opt[pos].off = offset; - opt[pos].litlen = ll; - opt[pos].price = price; - } } } - /* complete following positions with literals */ - { int addLit; - for (addLit = 1; addLit <= TRAILING_LITERALS; addLit ++) { - opt[last_match_pos+addLit].mlen = 1; /* literal */ - opt[last_match_pos+addLit].off = 0; - opt[last_match_pos+addLit].litlen = addLit; - opt[last_match_pos+addLit].price = opt[last_match_pos].price + LZ4HC_literalsPrice(addLit); - DEBUGLOG(7, "rPos:%3i => price:%3i (litlen=%i)", last_match_pos+addLit, opt[last_match_pos+addLit].price, addLit); - } } - } /* for (cur = 1; cur <= last_match_pos; cur++) */ - - assert(last_match_pos < LZ4_OPT_NUM + TRAILING_LITERALS); - best_mlen = opt[last_match_pos].mlen; - best_off = opt[last_match_pos].off; - cur = last_match_pos - best_mlen; - - encode: /* cur, last_match_pos, best_mlen, best_off must be set */ - assert(cur < LZ4_OPT_NUM); - assert(last_match_pos >= 1); /* == 1 when only one candidate */ - DEBUGLOG(6, "reverse traversal, looking for shortest path (last_match_pos=%i)", last_match_pos); - { int candidate_pos = cur; - int selected_matchLength = best_mlen; - int selected_offset = best_off; - while (1) { /* from end to beginning */ - int const next_matchLength = opt[candidate_pos].mlen; /* can be 1, means literal */ - int const next_offset = opt[candidate_pos].off; - DEBUGLOG(7, "pos %i: sequence length %i", candidate_pos, selected_matchLength); - opt[candidate_pos].mlen = selected_matchLength; - opt[candidate_pos].off = selected_offset; - selected_matchLength = next_matchLength; - selected_offset = next_offset; - if (next_matchLength > candidate_pos) break; /* last match elected, first match to encode */ - assert(next_matchLength > 0); /* can be 1, means literal */ - candidate_pos -= next_matchLength; - } } - - /* encode all recorded sequences in order */ - { int rPos = 0; /* relative position (to ip) */ - while (rPos < last_match_pos) { - int const ml = opt[rPos].mlen; - int const offset = opt[rPos].off; - if (ml == 1) { ip++; rPos++; continue; } /* literal; note: can end up with several literals, in which case, skip them */ - rPos += ml; - assert(ml >= MINMATCH); - assert((offset >= 1) && (offset <= LZ4_DISTANCE_MAX)); - opSaved = op; - if ( LZ4HC_encodeSequence(UPDATABLE(ip, op, anchor), ml, ip - offset, limit, oend) ) /* updates ip, op and anchor */ - goto _dest_overflow; - } } - } /* while (ip <= mflimit) */ - - _last_literals: - /* Encode Last Literals */ - { size_t lastRunSize = (size_t)(iend - anchor); /* literals */ - size_t litLength = (lastRunSize + 255 - RUN_MASK) / 255; - size_t const totalSize = 1 + litLength + lastRunSize; - if (limit == fillOutput) oend += LASTLITERALS; /* restore correct value */ - if (limit && (op + totalSize > oend)) { - if (limit == limitedOutput) return 0; /* Check output limit */ - /* adapt lastRunSize to fill 'dst' */ - lastRunSize = (size_t)(oend - op) - 1; - litLength = (lastRunSize + 255 - RUN_MASK) / 255; - lastRunSize -= litLength; - } - ip = anchor + lastRunSize; - - if (lastRunSize >= RUN_MASK) { - size_t accumulator = lastRunSize - RUN_MASK; - *op++ = (RUN_MASK << ML_BITS); - for(; accumulator >= 255 ; accumulator -= 255) *op++ = 255; - *op++ = (BYTE) accumulator; - } else { - *op++ = (BYTE)(lastRunSize << ML_BITS); - } - memcpy(op, anchor, lastRunSize); - op += lastRunSize; - } - - /* End */ - *srcSizePtr = (int) (((const char*)ip) - source); - return (int) ((char*)op-dst); - - _dest_overflow: - if (limit == fillOutput) { - op = opSaved; /* restore correct out pointer */ - goto _last_literals; - } - return 0; - } |