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-rw-r--r--lib/lz4/lz4hc.c1343
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diff --git a/lib/lz4/lz4hc.c b/lib/lz4/lz4hc.c
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--- a/lib/lz4/lz4hc.c
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-/*
- 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;
- }
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-02 11:35:59 +0000