| /* |
| LZ4 HC - High Compression Mode of LZ4 |
| Copyright (C) 2011-2020, 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 stateless HC compression functions like `LZ4_compress_HC()` |
| * allocate memory for their workspace: |
| * in stack (0:fastest), or in heap (1:default, requires malloc()). |
| * Since workspace 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 definitions ===*/ |
| #if defined(__GNUC__) |
| # pragma GCC diagnostic ignored "-Wunused-function" |
| #endif |
| #if defined (__clang__) |
| # pragma clang diagnostic ignored "-Wunused-function" |
| #endif |
| |
| #define LZ4_COMMONDEFS_ONLY |
| #ifndef LZ4_SRC_INCLUDED |
| #include "lz4.c" /* LZ4_count, constants, mem */ |
| #endif |
| |
| |
| /*=== Enums ===*/ |
| typedef enum { noDictCtx, usingDictCtxHc } dictCtx_directive; |
| |
| |
| /*=== 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 |
| |
| #define LZ4HC_HASHSIZE 4 |
| 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(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) |
| { |
| size_t const bufferSize = (size_t)(hc4->end - hc4->prefixStart); |
| size_t newStartingOffset = bufferSize + hc4->dictLimit; |
| DEBUGLOG(5, "LZ4HC_init_internal"); |
| assert(newStartingOffset >= bufferSize); /* check overflow */ |
| if (newStartingOffset > 1 GB) { |
| LZ4HC_clearTables(hc4); |
| newStartingOffset = 0; |
| } |
| newStartingOffset += 64 KB; |
| hc4->nextToUpdate = (U32)newStartingOffset; |
| hc4->prefixStart = start; |
| hc4->end = start; |
| hc4->dictStart = start; |
| hc4->dictLimit = (U32)newStartingOffset; |
| hc4->lowLimit = (U32)newStartingOffset; |
| } |
| |
| |
| /* 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 prefixPtr = hc4->prefixStart; |
| U32 const prefixIdx = hc4->dictLimit; |
| U32 const target = (U32)(ip - prefixPtr) + prefixIdx; |
| U32 idx = hc4->nextToUpdate; |
| assert(ip >= prefixPtr); |
| assert(target >= prefixIdx); |
| |
| while (idx < target) { |
| U32 const h = LZ4HC_hashPtr(prefixPtr+idx-prefixIdx); |
| 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) << (sizeof(pattern)*4)) : 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 endianness */ |
| 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 endianness */ |
| 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* const 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 prefixPtr = hc4->prefixStart; |
| const U32 prefixIdx = hc4->dictLimit; |
| const U32 ipIndex = (U32)(ip - prefixPtr) + prefixIdx; |
| const int withinStartDistance = (hc4->lowLimit + (LZ4_DISTANCE_MAX + 1) > ipIndex); |
| const U32 lowestMatchIndex = (withinStartDistance) ? hc4->lowLimit : ipIndex - LZ4_DISTANCE_MAX; |
| const BYTE* const dictStart = hc4->dictStart; |
| const U32 dictIdx = hc4->lowLimit; |
| const BYTE* const dictEnd = dictStart + prefixIdx - dictIdx; |
| 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>0)) { |
| int matchLength=0; |
| nbAttempts--; |
| assert(matchIndex < ipIndex); |
| if (favorDecSpeed && (ipIndex - matchIndex < 8)) { |
| /* do nothing */ |
| } else if (matchIndex >= prefixIdx) { /* within current Prefix */ |
| const BYTE* const matchPtr = prefixPtr + matchIndex - prefixIdx; |
| 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, prefixPtr) : 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 = dictStart + (matchIndex - dictIdx); |
| assert(matchIndex >= dictIdx); |
| if ( likely(matchIndex <= prefixIdx - 4) |
| && (LZ4_read32(matchPtr) == pattern) ) { |
| int back = 0; |
| const BYTE* vLimit = ip + (prefixIdx - 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, prefixPtr, iHighLimit); |
| back = lookBackLength ? LZ4HC_countBack(ip, matchPtr, iLowLimit, dictStart) : 0; |
| matchLength -= back; |
| if (matchLength > longest) { |
| longest = matchLength; |
| *matchpos = prefixPtr + matchIndex - prefixIdx + 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(prefixIdx, matchCandidateIdx) ) { |
| const int extDict = matchCandidateIdx < prefixIdx; |
| const BYTE* const matchPtr = (extDict ? dictStart - dictIdx : prefixPtr - prefixIdx) + matchCandidateIdx; |
| if (LZ4_read32(matchPtr) == pattern) { /* good candidate */ |
| const BYTE* const iLimit = extDict ? dictEnd : 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(prefixPtr, iHighLimit, rotatedPattern); |
| } |
| { const BYTE* const lowestMatchPtr = extDict ? dictStart : prefixPtr; |
| size_t backLength = LZ4HC_reverseCountPattern(matchPtr, lowestMatchPtr, pattern); |
| size_t currentSegmentLength; |
| if (!extDict |
| && matchPtr - backLength == prefixPtr |
| && dictIdx < prefixIdx) { |
| U32 const rotatedPattern = LZ4HC_rotatePattern((U32)(-(int)backLength), pattern); |
| backLength += LZ4HC_reverseCountPattern(dictEnd, 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(prefixIdx, newMatchIndex)) |
| matchIndex = newMatchIndex; |
| else { |
| /* Can only happen if started in the prefix */ |
| assert(newMatchIndex >= prefixIdx - 3 && newMatchIndex < prefixIdx && !extDict); |
| matchIndex = prefixIdx; |
| } |
| } 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(prefixIdx, newMatchIndex)) { |
| assert(newMatchIndex >= prefixIdx - 3 && newMatchIndex < prefixIdx && !extDict); |
| matchIndex = prefixIdx; |
| } else { |
| matchIndex = newMatchIndex; |
| if (lookBackLength==0) { /* no back possible */ |
| size_t const maxML = MIN(currentSegmentLength, srcPatternLength); |
| if ((size_t)longest < maxML) { |
| assert(prefixPtr - prefixIdx + matchIndex != ip); |
| if ((size_t)(ip - prefixPtr) + prefixIdx - matchIndex > LZ4_DISTANCE_MAX) break; |
| assert(maxML < 2 GB); |
| longest = (int)maxML; |
| *matchpos = prefixPtr - prefixIdx + 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 > 0 |
| && ipIndex - lowestMatchIndex < LZ4_DISTANCE_MAX) { |
| size_t const dictEndOffset = (size_t)(dictCtx->end - dictCtx->prefixStart) + dictCtx->dictLimit; |
| U32 dictMatchIndex = dictCtx->hashTable[LZ4HC_hashPtr(ip)]; |
| assert(dictEndOffset <= 1 GB); |
| matchIndex = dictMatchIndex + lowestMatchIndex - (U32)dictEndOffset; |
| if (dictMatchIndex>0) DEBUGLOG(7, "dictEndOffset = %zu, dictMatchIndex = %u => relative matchIndex = %i", dictEndOffset, dictMatchIndex, (int)dictMatchIndex - (int)dictEndOffset); |
| while (ipIndex - matchIndex <= LZ4_DISTANCE_MAX && nbAttempts--) { |
| const BYTE* const matchPtr = dictCtx->prefixStart - dictCtx->dictLimit + 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->prefixStart) : 0; |
| mlt -= back; |
| if (mlt > longest) { |
| longest = mlt; |
| *matchpos = prefixPtr - (prefixIdx - matchIndex) + back; |
| *startpos = ip + back; |
| DEBUGLOG(8, "found match of length %i at vPos=%i", longest, (int)matchIndex - (int)prefixIdx + 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; |
| DEBUGLOG(7, "LZ4HC_InsertAndFindBestMatch"); |
| /* 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) |
| { |
| #define ip (*_ip) |
| #define op (*_op) |
| #define anchor (*_anchor) |
| |
| 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:%4u, match:%4i, offset:%5u, cost:%4u + %5u", |
| pos, |
| (U32)(ip - anchor), matchLength, (U32)(ip-match), |
| cost, totalCost); |
| totalCost += cost; |
| #endif |
| |
| /* Encode Literal length */ |
| length = (size_t)(ip - anchor); |
| LZ4_STATIC_ASSERT(notLimited == 0); |
| /* Check output limit */ |
| if (limit && ((op + (length / 255) + length + (2 + 1 + LASTLITERALS)) > oend)) { |
| DEBUGLOG(6, "Not enough room to write %i literals (%i bytes remaining)", |
| (int)length, (int)(oend - op)); |
| return 1; |
| } |
| 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)) { |
| DEBUGLOG(6, "Not enough room to write match length"); |
| 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; |
| } |
| #undef ip |
| #undef op |
| #undef anchor |
| |
| LZ4_FORCE_INLINE int LZ4HC_compress_hashChain ( |
| LZ4HC_CCtx_internal* const ctx, |
| const char* const source, |
| char* const dest, |
| int* srcSizePtr, |
| int const maxOutputSize, |
| int 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 */ |
| DEBUGLOG(5, "LZ4HC_compress_hashChain (dict?=>%i)", dict); |
| *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)) { |
| ml = ml2; |
| ref = ref2; |
| 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 llAdd = (lastRunSize + 255 - RUN_MASK) / 255; |
| size_t const totalSize = 1 + llAdd + lastRunSize; |
| if (limit == fillOutput) oend += LASTLITERALS; /* restore correct value */ |
| if (limit && (op + totalSize > oend)) { |
| if (limit == limitedOutput) return 0; |
| /* adapt lastRunSize to fill 'dest' */ |
| lastRunSize = (size_t)(oend - op) - 1 /*token*/; |
| llAdd = (lastRunSize + 256 - RUN_MASK) / 256; |
| lastRunSize -= llAdd; |
| } |
| DEBUGLOG(6, "Final literal run : %i literals", (int)lastRunSize); |
| ip = anchor + lastRunSize; /* can be != iend if limit==fillOutput */ |
| |
| 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); |
| } |
| LZ4_memcpy(op, anchor, lastRunSize); |
| op += lastRunSize; |
| } |
| |
| /* End */ |
| *srcSizePtr = (int) (((const char*)ip) - source); |
| return (int) (((char*)op)-dest); |
| |
| _dest_overflow: |
| if (limit == fillOutput) { |
| /* Assumption : ip, anchor, ml and ref must be set correctly */ |
| size_t const ll = (size_t)(ip - anchor); |
| size_t const ll_addbytes = (ll + 240) / 255; |
| size_t const ll_totalCost = 1 + ll_addbytes + ll; |
| BYTE* const maxLitPos = oend - 3; /* 2 for offset, 1 for token */ |
| DEBUGLOG(6, "Last sequence overflowing"); |
| op = optr; /* restore correct out pointer */ |
| if (op + ll_totalCost <= maxLitPos) { |
| /* ll validated; now adjust match length */ |
| size_t const bytesLeftForMl = (size_t)(maxLitPos - (op+ll_totalCost)); |
| size_t const maxMlSize = MINMATCH + (ML_MASK-1) + (bytesLeftForMl * 255); |
| assert(maxMlSize < INT_MAX); assert(ml >= 0); |
| if ((size_t)ml > maxMlSize) ml = (int)maxMlSize; |
| if ((oend + LASTLITERALS) - (op + ll_totalCost + 2) - 1 + ml >= MFLIMIT) { |
| LZ4HC_encodeSequence(UPDATABLE(ip, op, anchor), ml, ref, notLimited, oend); |
| } } |
| goto _last_literals; |
| } |
| /* compression failed */ |
| 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, |
| const 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; |
| int 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(5, "LZ4HC_compress_generic_internal(src=%p, srcSize=%d)", |
| 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, |
| 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->prefixStart) + (ctx->dictLimit - 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) { |
| LZ4_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); } |
| |
| static size_t LZ4_streamHC_t_alignment(void) |
| { |
| #if LZ4_ALIGN_TEST |
| typedef struct { char c; LZ4_streamHC_t t; } t_a; |
| return sizeof(t_a) - sizeof(LZ4_streamHC_t); |
| #else |
| return 1; /* effectively disabled */ |
| #endif |
| } |
| |
| /* state is presumed correctly initialized, |
| * in which case its size and alignment have already been validate */ |
| 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; |
| if (!LZ4_isAligned(state, LZ4_streamHC_t_alignment())) return 0; |
| 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) |
| { |
| int cSize; |
| #if defined(LZ4HC_HEAPMODE) && LZ4HC_HEAPMODE==1 |
| LZ4_streamHC_t* const statePtr = (LZ4_streamHC_t*)ALLOC(sizeof(LZ4_streamHC_t)); |
| if (statePtr==NULL) return 0; |
| #else |
| LZ4_streamHC_t state; |
| LZ4_streamHC_t* const statePtr = &state; |
| #endif |
| DEBUGLOG(5, "LZ4_compress_HC") |
| 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 |
| **************************************/ |
| /* allocation */ |
| #if !defined(LZ4_STATIC_LINKING_ONLY_DISABLE_MEMORY_ALLOCATION) |
| LZ4_streamHC_t* LZ4_createStreamHC(void) |
| { |
| LZ4_streamHC_t* const state = |
| (LZ4_streamHC_t*)ALLOC_AND_ZERO(sizeof(LZ4_streamHC_t)); |
| if (state == NULL) return NULL; |
| LZ4_setCompressionLevel(state, LZ4HC_CLEVEL_DEFAULT); |
| return state; |
| } |
| |
| int LZ4_freeStreamHC (LZ4_streamHC_t* LZ4_streamHCPtr) |
| { |
| DEBUGLOG(4, "LZ4_freeStreamHC(%p)", LZ4_streamHCPtr); |
| if (!LZ4_streamHCPtr) return 0; /* support free on NULL */ |
| FREEMEM(LZ4_streamHCPtr); |
| return 0; |
| } |
| #endif |
| |
| |
| LZ4_streamHC_t* LZ4_initStreamHC (void* buffer, size_t size) |
| { |
| LZ4_streamHC_t* const LZ4_streamHCPtr = (LZ4_streamHC_t*)buffer; |
| DEBUGLOG(4, "LZ4_initStreamHC(%p, %u)", buffer, (unsigned)size); |
| /* check conditions */ |
| if (buffer == NULL) return NULL; |
| if (size < sizeof(LZ4_streamHC_t)) return NULL; |
| if (!LZ4_isAligned(buffer, LZ4_streamHC_t_alignment())) return NULL; |
| /* init */ |
| { LZ4HC_CCtx_internal* const hcstate = &(LZ4_streamHCPtr->internal_donotuse); |
| MEM_INIT(hcstate, 0, sizeof(*hcstate)); } |
| LZ4_setCompressionLevel(LZ4_streamHCPtr, LZ4HC_CLEVEL_DEFAULT); |
| return LZ4_streamHCPtr; |
| } |
| |
| /* just a stub */ |
| void LZ4_resetStreamHC (LZ4_streamHC_t* LZ4_streamHCPtr, int compressionLevel) |
| { |
| LZ4_initStreamHC(LZ4_streamHCPtr, sizeof(*LZ4_streamHCPtr)); |
| LZ4_setCompressionLevel(LZ4_streamHCPtr, compressionLevel); |
| } |
| |
| void LZ4_resetStreamHC_fast (LZ4_streamHC_t* LZ4_streamHCPtr, int compressionLevel) |
| { |
| LZ4HC_CCtx_internal* const s = &LZ4_streamHCPtr->internal_donotuse; |
| DEBUGLOG(5, "LZ4_resetStreamHC_fast(%p, %d)", LZ4_streamHCPtr, compressionLevel); |
| if (s->dirty) { |
| LZ4_initStreamHC(LZ4_streamHCPtr, sizeof(*LZ4_streamHCPtr)); |
| } else { |
| assert(s->end >= s->prefixStart); |
| s->dictLimit += (U32)(s->end - s->prefixStart); |
| s->prefixStart = NULL; |
| s->end = NULL; |
| s->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; |
| } |
| |
| void LZ4_favorDecompressionSpeed(LZ4_streamHC_t* LZ4_streamHCPtr, int favor) |
| { |
| LZ4_streamHCPtr->internal_donotuse.favorDecSpeed = (favor!=0); |
| } |
| |
| /* LZ4_loadDictHC() : |
| * LZ4_streamHCPtr is presumed properly initialized */ |
| int LZ4_loadDictHC (LZ4_streamHC_t* LZ4_streamHCPtr, |
| const char* dictionary, int dictSize) |
| { |
| LZ4HC_CCtx_internal* const ctxPtr = &LZ4_streamHCPtr->internal_donotuse; |
| DEBUGLOG(4, "LZ4_loadDictHC(ctx:%p, dict:%p, dictSize:%d)", LZ4_streamHCPtr, dictionary, dictSize); |
| assert(LZ4_streamHCPtr != NULL); |
| if (dictSize > 64 KB) { |
| dictionary += (size_t)dictSize - 64 KB; |
| dictSize = 64 KB; |
| } |
| /* need a full initialization, there are bad side-effects when using resetFast() */ |
| { int const cLevel = ctxPtr->compressionLevel; |
| LZ4_initStreamHC(LZ4_streamHCPtr, sizeof(*LZ4_streamHCPtr)); |
| LZ4_setCompressionLevel(LZ4_streamHCPtr, cLevel); |
| } |
| LZ4HC_init_internal (ctxPtr, (const BYTE*)dictionary); |
| ctxPtr->end = (const BYTE*)dictionary + dictSize; |
| if (dictSize >= LZ4HC_HASHSIZE) LZ4HC_Insert (ctxPtr, ctxPtr->end-3); |
| return dictSize; |
| } |
| |
| void LZ4_attach_HC_dictionary(LZ4_streamHC_t *working_stream, const LZ4_streamHC_t *dictionary_stream) { |
| working_stream->internal_donotuse.dictCtx = dictionary_stream != NULL ? &(dictionary_stream->internal_donotuse) : NULL; |
| } |
| |
| /* compression */ |
| |
| static void LZ4HC_setExternalDict(LZ4HC_CCtx_internal* ctxPtr, const BYTE* newBlock) |
| { |
| DEBUGLOG(4, "LZ4HC_setExternalDict(%p, %p)", ctxPtr, newBlock); |
| if (ctxPtr->end >= ctxPtr->prefixStart + 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->dictStart = ctxPtr->prefixStart; |
| ctxPtr->dictLimit += (U32)(ctxPtr->end - ctxPtr->prefixStart); |
| ctxPtr->prefixStart = newBlock; |
| 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; |
| } |
| |
| static int |
| LZ4_compressHC_continue_generic (LZ4_streamHC_t* LZ4_streamHCPtr, |
| const char* src, char* dst, |
| int* srcSizePtr, int dstCapacity, |
| limitedOutput_directive limit) |
| { |
| LZ4HC_CCtx_internal* const ctxPtr = &LZ4_streamHCPtr->internal_donotuse; |
| DEBUGLOG(5, "LZ4_compressHC_continue_generic(ctx=%p, src=%p, srcSize=%d, limit=%d)", |
| LZ4_streamHCPtr, src, *srcSizePtr, limit); |
| assert(ctxPtr != NULL); |
| /* auto-init if forgotten */ |
| if (ctxPtr->prefixStart == NULL) LZ4HC_init_internal (ctxPtr, (const BYTE*) src); |
| |
| /* Check overflow */ |
| if ((size_t)(ctxPtr->end - ctxPtr->prefixStart) + ctxPtr->dictLimit > 2 GB) { |
| size_t dictSize = (size_t)(ctxPtr->end - ctxPtr->prefixStart); |
| if (dictSize > 64 KB) dictSize = 64 KB; |
| LZ4_loadDictHC(LZ4_streamHCPtr, (const char*)(ctxPtr->end) - dictSize, (int)dictSize); |
| } |
| |
| /* Check if blocks follow each other */ |
| if ((const BYTE*)src != ctxPtr->end) |
| LZ4HC_setExternalDict(ctxPtr, (const BYTE*)src); |
| |
| /* Check overlapping input/dictionary space */ |
| { const BYTE* sourceEnd = (const BYTE*) src + *srcSizePtr; |
| const BYTE* const dictBegin = ctxPtr->dictStart; |
| const BYTE* const dictEnd = ctxPtr->dictStart + (ctxPtr->dictLimit - ctxPtr->lowLimit); |
| if ((sourceEnd > dictBegin) && ((const BYTE*)src < dictEnd)) { |
| if (sourceEnd > dictEnd) sourceEnd = dictEnd; |
| ctxPtr->lowLimit += (U32)(sourceEnd - ctxPtr->dictStart); |
| ctxPtr->dictStart += (U32)(sourceEnd - ctxPtr->dictStart); |
| /* invalidate dictionary is it's too small */ |
| if (ctxPtr->dictLimit - ctxPtr->lowLimit < LZ4HC_HASHSIZE) { |
| ctxPtr->lowLimit = ctxPtr->dictLimit; |
| ctxPtr->dictStart = ctxPtr->prefixStart; |
| } } } |
| |
| return LZ4HC_compress_generic (ctxPtr, src, dst, srcSizePtr, dstCapacity, ctxPtr->compressionLevel, limit); |
| } |
| |
| int LZ4_compress_HC_continue (LZ4_streamHC_t* LZ4_streamHCPtr, const char* src, char* dst, int srcSize, int dstCapacity) |
| { |
| DEBUGLOG(5, "LZ4_compress_HC_continue"); |
| if (dstCapacity < LZ4_compressBound(srcSize)) |
| return LZ4_compressHC_continue_generic (LZ4_streamHCPtr, src, dst, &srcSize, dstCapacity, limitedOutput); |
| else |
| return LZ4_compressHC_continue_generic (LZ4_streamHCPtr, src, dst, &srcSize, dstCapacity, notLimited); |
| } |
| |
| int LZ4_compress_HC_continue_destSize (LZ4_streamHC_t* LZ4_streamHCPtr, const char* src, char* dst, int* srcSizePtr, int targetDestSize) |
| { |
| return LZ4_compressHC_continue_generic(LZ4_streamHCPtr, src, dst, srcSizePtr, targetDestSize, fillOutput); |
| } |
| |
| |
| |
| /* LZ4_saveDictHC : |
| * save history content |
| * into a user-provided buffer |
| * which is then used to continue compression |
| */ |
| int LZ4_saveDictHC (LZ4_streamHC_t* LZ4_streamHCPtr, char* safeBuffer, int dictSize) |
| { |
| LZ4HC_CCtx_internal* const streamPtr = &LZ4_streamHCPtr->internal_donotuse; |
| int const prefixSize = (int)(streamPtr->end - streamPtr->prefixStart); |
| DEBUGLOG(5, "LZ4_saveDictHC(%p, %p, %d)", LZ4_streamHCPtr, safeBuffer, dictSize); |
| assert(prefixSize >= 0); |
| if (dictSize > 64 KB) dictSize = 64 KB; |
| if (dictSize < 4) dictSize = 0; |
| if (dictSize > prefixSize) dictSize = prefixSize; |
| if (safeBuffer == NULL) assert(dictSize == 0); |
| if (dictSize > 0) |
| LZ4_memmove(safeBuffer, streamPtr->end - dictSize, (size_t)dictSize); |
| { U32 const endIndex = (U32)(streamPtr->end - streamPtr->prefixStart) + streamPtr->dictLimit; |
| streamPtr->end = (safeBuffer == NULL) ? NULL : (const BYTE*)safeBuffer + dictSize; |
| streamPtr->prefixStart = (const BYTE*)safeBuffer; |
| streamPtr->dictLimit = endIndex - (U32)dictSize; |
| streamPtr->lowLimit = endIndex - (U32)dictSize; |
| streamPtr->dictStart = streamPtr->prefixStart; |
| if (streamPtr->nextToUpdate < streamPtr->dictLimit) |
| streamPtr->nextToUpdate = streamPtr->dictLimit; |
| } |
| return dictSize; |
| } |
| |
| |
| /*************************************************** |
| * Deprecated Functions |
| ***************************************************/ |
| |
| /* These functions currently generate deprecation warnings */ |
| |
| /* Wrappers for deprecated compression functions */ |
| int LZ4_compressHC(const char* src, char* dst, int srcSize) { return LZ4_compress_HC (src, dst, srcSize, LZ4_compressBound(srcSize), 0); } |
| int LZ4_compressHC_limitedOutput(const char* src, char* dst, int srcSize, int maxDstSize) { return LZ4_compress_HC(src, dst, srcSize, maxDstSize, 0); } |
| int LZ4_compressHC2(const char* src, char* dst, int srcSize, int cLevel) { return LZ4_compress_HC (src, dst, srcSize, LZ4_compressBound(srcSize), cLevel); } |
| int LZ4_compressHC2_limitedOutput(const char* src, char* dst, int srcSize, int maxDstSize, int cLevel) { return LZ4_compress_HC(src, dst, srcSize, maxDstSize, cLevel); } |
| int LZ4_compressHC_withStateHC (void* state, const char* src, char* dst, int srcSize) { return LZ4_compress_HC_extStateHC (state, src, dst, srcSize, LZ4_compressBound(srcSize), 0); } |
| int LZ4_compressHC_limitedOutput_withStateHC (void* state, const char* src, char* dst, int srcSize, int maxDstSize) { return LZ4_compress_HC_extStateHC (state, src, dst, srcSize, maxDstSize, 0); } |
| int LZ4_compressHC2_withStateHC (void* state, const char* src, char* dst, int srcSize, int cLevel) { return LZ4_compress_HC_extStateHC(state, src, dst, srcSize, LZ4_compressBound(srcSize), cLevel); } |
| int LZ4_compressHC2_limitedOutput_withStateHC (void* state, const char* src, char* dst, int srcSize, int maxDstSize, int cLevel) { return LZ4_compress_HC_extStateHC(state, src, dst, srcSize, maxDstSize, cLevel); } |
| int LZ4_compressHC_continue (LZ4_streamHC_t* ctx, const char* src, char* dst, int srcSize) { return LZ4_compress_HC_continue (ctx, src, dst, srcSize, LZ4_compressBound(srcSize)); } |
| int LZ4_compressHC_limitedOutput_continue (LZ4_streamHC_t* ctx, const char* src, char* dst, int srcSize, int maxDstSize) { return LZ4_compress_HC_continue (ctx, src, dst, srcSize, maxDstSize); } |
| |
| |
| /* Deprecated streaming functions */ |
| int LZ4_sizeofStreamStateHC(void) { return sizeof(LZ4_streamHC_t); } |
| |
| /* state is presumed correctly sized, aka >= sizeof(LZ4_streamHC_t) |
| * @return : 0 on success, !=0 if error */ |
| int LZ4_resetStreamStateHC(void* state, char* inputBuffer) |
| { |
| LZ4_streamHC_t* const hc4 = LZ4_initStreamHC(state, sizeof(*hc4)); |
| if (hc4 == NULL) return 1; /* init failed */ |
| LZ4HC_init_internal (&hc4->internal_donotuse, (const BYTE*)inputBuffer); |
| return 0; |
| } |
| |
| #if !defined(LZ4_STATIC_LINKING_ONLY_DISABLE_MEMORY_ALLOCATION) |
| void* LZ4_createHC (const char* inputBuffer) |
| { |
| LZ4_streamHC_t* const hc4 = LZ4_createStreamHC(); |
| if (hc4 == NULL) return NULL; /* not enough memory */ |
| LZ4HC_init_internal (&hc4->internal_donotuse, (const BYTE*)inputBuffer); |
| return hc4; |
| } |
| |
| int LZ4_freeHC (void* LZ4HC_Data) |
| { |
| if (!LZ4HC_Data) return 0; /* support free on NULL */ |
| FREEMEM(LZ4HC_Data); |
| return 0; |
| } |
| #endif |
| |
| int LZ4_compressHC2_continue (void* LZ4HC_Data, const char* src, char* dst, int srcSize, int cLevel) |
| { |
| return LZ4HC_compress_generic (&((LZ4_streamHC_t*)LZ4HC_Data)->internal_donotuse, src, dst, &srcSize, 0, cLevel, notLimited); |
| } |
| |
| int LZ4_compressHC2_limitedOutput_continue (void* LZ4HC_Data, const char* src, char* dst, int srcSize, int dstCapacity, int cLevel) |
| { |
| return LZ4HC_compress_generic (&((LZ4_streamHC_t*)LZ4HC_Data)->internal_donotuse, src, dst, &srcSize, dstCapacity, cLevel, limitedOutput); |
| } |
| |
| char* LZ4_slideInputBufferHC(void* LZ4HC_Data) |
| { |
| LZ4HC_CCtx_internal* const s = &((LZ4_streamHC_t*)LZ4HC_Data)->internal_donotuse; |
| const BYTE* const bufferStart = s->prefixStart - s->dictLimit + s->lowLimit; |
| LZ4_resetStreamHC_fast((LZ4_streamHC_t*)LZ4HC_Data, s->compressionLevel); |
| /* ugly conversion trick, required to evade (const char*) -> (char*) cast-qual warning :( */ |
| return (char*)(uptrval)bufferStart; |
| } |
| |
| |
| /* ================================================ |
| * 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) |
| { |
| int retval = 0; |
| #define TRAILING_LITERALS 3 |
| #if defined(LZ4HC_HEAPMODE) && LZ4HC_HEAPMODE==1 |
| LZ4HC_optimal_t* const opt = (LZ4HC_optimal_t*)ALLOC(sizeof(LZ4HC_optimal_t) * (LZ4_OPT_NUM + TRAILING_LITERALS)); |
| #else |
| LZ4HC_optimal_t opt[LZ4_OPT_NUM + TRAILING_LITERALS]; /* ~64 KB, which is a bit large for stack... */ |
| #endif |
| |
| 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; |
| int ovml = MINMATCH; /* overflow - last sequence */ |
| const BYTE* ovref = NULL; |
| |
| /* init */ |
| #if defined(LZ4HC_HEAPMODE) && LZ4HC_HEAPMODE==1 |
| if (opt == NULL) goto _return_label; |
| #endif |
| 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 */ |
| 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 */ |
| ovml = firstML; |
| ovref = matchPos; |
| 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 */ |
| ovml = ml; |
| ovref = ip - offset; |
| goto _dest_overflow; |
| } } } |
| } /* while (ip <= mflimit) */ |
| |
| _last_literals: |
| /* Encode Last Literals */ |
| { size_t lastRunSize = (size_t)(iend - anchor); /* literals */ |
| size_t llAdd = (lastRunSize + 255 - RUN_MASK) / 255; |
| size_t const totalSize = 1 + llAdd + lastRunSize; |
| if (limit == fillOutput) oend += LASTLITERALS; /* restore correct value */ |
| if (limit && (op + totalSize > oend)) { |
| if (limit == limitedOutput) { /* Check output limit */ |
| retval = 0; |
| goto _return_label; |
| } |
| /* adapt lastRunSize to fill 'dst' */ |
| lastRunSize = (size_t)(oend - op) - 1 /*token*/; |
| llAdd = (lastRunSize + 256 - RUN_MASK) / 256; |
| lastRunSize -= llAdd; |
| } |
| DEBUGLOG(6, "Final literal run : %i literals", (int)lastRunSize); |
| ip = anchor + lastRunSize; /* can be != iend if limit==fillOutput */ |
| |
| 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); |
| } |
| LZ4_memcpy(op, anchor, lastRunSize); |
| op += lastRunSize; |
| } |
| |
| /* End */ |
| *srcSizePtr = (int) (((const char*)ip) - source); |
| retval = (int) ((char*)op-dst); |
| goto _return_label; |
| |
| _dest_overflow: |
| if (limit == fillOutput) { |
| /* Assumption : ip, anchor, ovml and ovref must be set correctly */ |
| size_t const ll = (size_t)(ip - anchor); |
| size_t const ll_addbytes = (ll + 240) / 255; |
| size_t const ll_totalCost = 1 + ll_addbytes + ll; |
| BYTE* const maxLitPos = oend - 3; /* 2 for offset, 1 for token */ |
| DEBUGLOG(6, "Last sequence overflowing (only %i bytes remaining)", (int)(oend-1-opSaved)); |
| op = opSaved; /* restore correct out pointer */ |
| if (op + ll_totalCost <= maxLitPos) { |
| /* ll validated; now adjust match length */ |
| size_t const bytesLeftForMl = (size_t)(maxLitPos - (op+ll_totalCost)); |
| size_t const maxMlSize = MINMATCH + (ML_MASK-1) + (bytesLeftForMl * 255); |
| assert(maxMlSize < INT_MAX); assert(ovml >= 0); |
| if ((size_t)ovml > maxMlSize) ovml = (int)maxMlSize; |
| if ((oend + LASTLITERALS) - (op + ll_totalCost + 2) - 1 + ovml >= MFLIMIT) { |
| DEBUGLOG(6, "Space to end : %i + ml (%i)", (int)((oend + LASTLITERALS) - (op + ll_totalCost + 2) - 1), ovml); |
| DEBUGLOG(6, "Before : ip = %p, anchor = %p", ip, anchor); |
| LZ4HC_encodeSequence(UPDATABLE(ip, op, anchor), ovml, ovref, notLimited, oend); |
| DEBUGLOG(6, "After : ip = %p, anchor = %p", ip, anchor); |
| } } |
| goto _last_literals; |
| } |
| _return_label: |
| #if defined(LZ4HC_HEAPMODE) && LZ4HC_HEAPMODE==1 |
| FREEMEM(opt); |
| #endif |
| return retval; |
| } |