1539 lines
65 KiB
C
1539 lines
65 KiB
C
/*
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LZ4 HC - High Compression Mode of LZ4
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Copyright (C) 2011-2017, Yann Collet.
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BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are
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met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above
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copyright notice, this list of conditions and the following disclaimer
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in the documentation and/or other materials provided with the
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distribution.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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You can contact the author at :
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- LZ4 source repository : https://github.com/lz4/lz4
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- LZ4 public forum : https://groups.google.com/forum/#!forum/lz4c
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*/
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/* note : lz4hc is not an independent module, it requires lz4.h/lz4.c for proper compilation */
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/* *************************************
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* Tuning Parameter
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***************************************/
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/*! HEAPMODE :
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* Select how default compression function will allocate workplace memory,
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* in stack (0:fastest), or in heap (1:requires malloc()).
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* Since workplace is rather large, heap mode is recommended.
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*/
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#ifndef LZ4HC_HEAPMODE
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# define LZ4HC_HEAPMODE 1
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#endif
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/*=== Dependency ===*/
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#define LZ4_HC_STATIC_LINKING_ONLY
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#include "lz4hc.h"
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/*=== Common LZ4 definitions ===*/
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#if defined(__GNUC__)
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# pragma GCC diagnostic ignored "-Wunused-function"
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#endif
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#if defined (__clang__)
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# pragma clang diagnostic ignored "-Wunused-function"
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#endif
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/*=== Enums ===*/
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typedef enum { noDictCtx, usingDictCtxHc } dictCtx_directive;
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#define LZ4_COMMONDEFS_ONLY
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#ifndef LZ4_SRC_INCLUDED
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#include "lz4.c" /* LZ4_count, constants, mem */
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#endif
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/*=== Constants ===*/
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#define OPTIMAL_ML (int)((ML_MASK-1)+MINMATCH)
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#define LZ4_OPT_NUM (1<<12)
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/*=== Macros ===*/
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#define MIN(a,b) ( (a) < (b) ? (a) : (b) )
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#define MAX(a,b) ( (a) > (b) ? (a) : (b) )
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#define HASH_FUNCTION(i) (((i) * 2654435761U) >> ((MINMATCH*8)-LZ4HC_HASH_LOG))
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#define DELTANEXTMAXD(p) chainTable[(p) & LZ4HC_MAXD_MASK] /* flexible, LZ4HC_MAXD dependent */
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#define DELTANEXTU16(table, pos) table[(U16)(pos)] /* faster */
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/* Make fields passed to, and updated by LZ4HC_encodeSequence explicit */
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#define UPDATABLE(ip, op, anchor) &ip, &op, &anchor
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static U32 LZ4HC_hashPtr(const void* ptr) { return HASH_FUNCTION(LZ4_read32(ptr)); }
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/**************************************
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* HC Compression
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**************************************/
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static void LZ4HC_clearTables (LZ4HC_CCtx_internal* hc4)
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{
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MEM_INIT((void*)hc4->hashTable, 0, sizeof(hc4->hashTable));
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MEM_INIT(hc4->chainTable, 0xFF, sizeof(hc4->chainTable));
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}
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static void LZ4HC_init_internal (LZ4HC_CCtx_internal* hc4, const BYTE* start)
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{
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uptrval startingOffset = (uptrval)(hc4->end - hc4->base);
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if (startingOffset > 1 GB) {
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LZ4HC_clearTables(hc4);
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startingOffset = 0;
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}
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startingOffset += 64 KB;
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hc4->nextToUpdate = (U32) startingOffset;
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hc4->base = start - startingOffset;
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hc4->end = start;
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hc4->dictBase = start - startingOffset;
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hc4->dictLimit = (U32) startingOffset;
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hc4->lowLimit = (U32) startingOffset;
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}
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/* Update chains up to ip (excluded) */
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LZ4_FORCE_INLINE void LZ4HC_Insert (LZ4HC_CCtx_internal* hc4, const BYTE* ip)
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{
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U16* const chainTable = hc4->chainTable;
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U32* const hashTable = hc4->hashTable;
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const BYTE* const base = hc4->base;
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U32 const target = (U32)(ip - base);
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U32 idx = hc4->nextToUpdate;
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while (idx < target) {
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U32 const h = LZ4HC_hashPtr(base+idx);
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size_t delta = idx - hashTable[h];
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if (delta>LZ4_DISTANCE_MAX) delta = LZ4_DISTANCE_MAX;
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DELTANEXTU16(chainTable, idx) = (U16)delta;
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hashTable[h] = idx;
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idx++;
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}
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hc4->nextToUpdate = target;
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}
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/** LZ4HC_countBack() :
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* @return : negative value, nb of common bytes before ip/match */
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LZ4_FORCE_INLINE
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int LZ4HC_countBack(const BYTE* const ip, const BYTE* const match,
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const BYTE* const iMin, const BYTE* const mMin)
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{
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int back = 0;
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int const min = (int)MAX(iMin - ip, mMin - match);
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assert(min <= 0);
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assert(ip >= iMin); assert((size_t)(ip-iMin) < (1U<<31));
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assert(match >= mMin); assert((size_t)(match - mMin) < (1U<<31));
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while ( (back > min)
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&& (ip[back-1] == match[back-1]) )
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back--;
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return back;
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}
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#if defined(_MSC_VER)
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# define LZ4HC_rotl32(x,r) _rotl(x,r)
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#else
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# define LZ4HC_rotl32(x,r) ((x << r) | (x >> (32 - r)))
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#endif
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static U32 LZ4HC_rotatePattern(size_t const rotate, U32 const pattern)
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{
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size_t const bitsToRotate = (rotate & (sizeof(pattern) - 1)) << 3;
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if (bitsToRotate == 0)
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return pattern;
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return LZ4HC_rotl32(pattern, (int)bitsToRotate);
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}
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/* LZ4HC_countPattern() :
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* pattern32 must be a sample of repetitive pattern of length 1, 2 or 4 (but not 3!) */
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static unsigned
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LZ4HC_countPattern(const BYTE* ip, const BYTE* const iEnd, U32 const pattern32)
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{
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const BYTE* const iStart = ip;
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reg_t const pattern = (sizeof(pattern)==8) ? (reg_t)pattern32 + (((reg_t)pattern32) << 32) : pattern32;
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while (likely(ip < iEnd-(sizeof(pattern)-1))) {
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reg_t const diff = LZ4_read_ARCH(ip) ^ pattern;
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if (!diff) { ip+=sizeof(pattern); continue; }
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ip += LZ4_NbCommonBytes(diff);
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return (unsigned)(ip - iStart);
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}
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if (LZ4_isLittleEndian()) {
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reg_t patternByte = pattern;
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while ((ip<iEnd) && (*ip == (BYTE)patternByte)) {
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ip++; patternByte >>= 8;
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}
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} else { /* big endian */
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U32 bitOffset = (sizeof(pattern)*8) - 8;
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while (ip < iEnd) {
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BYTE const byte = (BYTE)(pattern >> bitOffset);
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if (*ip != byte) break;
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ip ++; bitOffset -= 8;
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}
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}
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return (unsigned)(ip - iStart);
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}
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/* LZ4HC_reverseCountPattern() :
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* pattern must be a sample of repetitive pattern of length 1, 2 or 4 (but not 3!)
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* read using natural platform endianess */
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static unsigned
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LZ4HC_reverseCountPattern(const BYTE* ip, const BYTE* const iLow, U32 pattern)
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{
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const BYTE* const iStart = ip;
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while (likely(ip >= iLow+4)) {
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if (LZ4_read32(ip-4) != pattern) break;
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ip -= 4;
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}
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{ const BYTE* bytePtr = (const BYTE*)(&pattern) + 3; /* works for any endianess */
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while (likely(ip>iLow)) {
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if (ip[-1] != *bytePtr) break;
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ip--; bytePtr--;
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} }
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return (unsigned)(iStart - ip);
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}
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/* LZ4HC_protectDictEnd() :
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* Checks if the match is in the last 3 bytes of the dictionary, so reading the
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* 4 byte MINMATCH would overflow.
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* @returns true if the match index is okay.
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*/
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static int LZ4HC_protectDictEnd(U32 const dictLimit, U32 const matchIndex)
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{
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return ((U32)((dictLimit - 1) - matchIndex) >= 3);
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}
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typedef enum { rep_untested, rep_not, rep_confirmed } repeat_state_e;
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typedef enum { favorCompressionRatio=0, favorDecompressionSpeed } HCfavor_e;
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LZ4_FORCE_INLINE int
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LZ4HC_InsertAndGetWiderMatch (
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LZ4HC_CCtx_internal* hc4,
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const BYTE* const ip,
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const BYTE* const iLowLimit,
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const BYTE* const iHighLimit,
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int longest,
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const BYTE** matchpos,
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const BYTE** startpos,
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const int maxNbAttempts,
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const int patternAnalysis,
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const int chainSwap,
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const dictCtx_directive dict,
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const HCfavor_e favorDecSpeed)
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{
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U16* const chainTable = hc4->chainTable;
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U32* const HashTable = hc4->hashTable;
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const LZ4HC_CCtx_internal * const dictCtx = hc4->dictCtx;
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const BYTE* const base = hc4->base;
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const U32 dictLimit = hc4->dictLimit;
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const BYTE* const lowPrefixPtr = base + dictLimit;
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const U32 ipIndex = (U32)(ip - base);
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const U32 lowestMatchIndex = (hc4->lowLimit + (LZ4_DISTANCE_MAX + 1) > ipIndex) ? hc4->lowLimit : ipIndex - LZ4_DISTANCE_MAX;
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const BYTE* const dictBase = hc4->dictBase;
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int const lookBackLength = (int)(ip-iLowLimit);
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int nbAttempts = maxNbAttempts;
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U32 matchChainPos = 0;
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U32 const pattern = LZ4_read32(ip);
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U32 matchIndex;
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repeat_state_e repeat = rep_untested;
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size_t srcPatternLength = 0;
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DEBUGLOG(7, "LZ4HC_InsertAndGetWiderMatch");
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/* First Match */
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LZ4HC_Insert(hc4, ip);
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matchIndex = HashTable[LZ4HC_hashPtr(ip)];
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DEBUGLOG(7, "First match at index %u / %u (lowestMatchIndex)",
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matchIndex, lowestMatchIndex);
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while ((matchIndex>=lowestMatchIndex) && (nbAttempts)) {
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int matchLength=0;
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nbAttempts--;
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assert(matchIndex < ipIndex);
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if (favorDecSpeed && (ipIndex - matchIndex < 8)) {
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/* do nothing */
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} else if (matchIndex >= dictLimit) { /* within current Prefix */
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const BYTE* const matchPtr = base + matchIndex;
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assert(matchPtr >= lowPrefixPtr);
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assert(matchPtr < ip);
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assert(longest >= 1);
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if (LZ4_read16(iLowLimit + longest - 1) == LZ4_read16(matchPtr - lookBackLength + longest - 1)) {
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if (LZ4_read32(matchPtr) == pattern) {
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int const back = lookBackLength ? LZ4HC_countBack(ip, matchPtr, iLowLimit, lowPrefixPtr) : 0;
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matchLength = MINMATCH + (int)LZ4_count(ip+MINMATCH, matchPtr+MINMATCH, iHighLimit);
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matchLength -= back;
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if (matchLength > longest) {
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longest = matchLength;
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*matchpos = matchPtr + back;
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*startpos = ip + back;
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} } }
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} else { /* lowestMatchIndex <= matchIndex < dictLimit */
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const BYTE* const matchPtr = dictBase + matchIndex;
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if (LZ4_read32(matchPtr) == pattern) {
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const BYTE* const dictStart = dictBase + hc4->lowLimit;
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int back = 0;
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const BYTE* vLimit = ip + (dictLimit - matchIndex);
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if (vLimit > iHighLimit) vLimit = iHighLimit;
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matchLength = (int)LZ4_count(ip+MINMATCH, matchPtr+MINMATCH, vLimit) + MINMATCH;
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if ((ip+matchLength == vLimit) && (vLimit < iHighLimit))
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matchLength += LZ4_count(ip+matchLength, lowPrefixPtr, iHighLimit);
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back = lookBackLength ? LZ4HC_countBack(ip, matchPtr, iLowLimit, dictStart) : 0;
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matchLength -= back;
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if (matchLength > longest) {
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longest = matchLength;
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*matchpos = base + matchIndex + back; /* virtual pos, relative to ip, to retrieve offset */
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*startpos = ip + back;
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} } }
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if (chainSwap && matchLength==longest) { /* better match => select a better chain */
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assert(lookBackLength==0); /* search forward only */
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if (matchIndex + (U32)longest <= ipIndex) {
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int const kTrigger = 4;
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U32 distanceToNextMatch = 1;
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int const end = longest - MINMATCH + 1;
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int step = 1;
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int accel = 1 << kTrigger;
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int pos;
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for (pos = 0; pos < end; pos += step) {
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U32 const candidateDist = DELTANEXTU16(chainTable, matchIndex + (U32)pos);
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step = (accel++ >> kTrigger);
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if (candidateDist > distanceToNextMatch) {
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distanceToNextMatch = candidateDist;
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matchChainPos = (U32)pos;
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accel = 1 << kTrigger;
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}
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}
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if (distanceToNextMatch > 1) {
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if (distanceToNextMatch > matchIndex) break; /* avoid overflow */
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matchIndex -= distanceToNextMatch;
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continue;
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} } }
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{ U32 const distNextMatch = DELTANEXTU16(chainTable, matchIndex);
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if (patternAnalysis && distNextMatch==1 && matchChainPos==0) {
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U32 const matchCandidateIdx = matchIndex-1;
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/* may be a repeated pattern */
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if (repeat == rep_untested) {
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if ( ((pattern & 0xFFFF) == (pattern >> 16))
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& ((pattern & 0xFF) == (pattern >> 24)) ) {
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repeat = rep_confirmed;
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srcPatternLength = LZ4HC_countPattern(ip+sizeof(pattern), iHighLimit, pattern) + sizeof(pattern);
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} else {
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repeat = rep_not;
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} }
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if ( (repeat == rep_confirmed) && (matchCandidateIdx >= lowestMatchIndex)
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&& LZ4HC_protectDictEnd(dictLimit, matchCandidateIdx) ) {
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const int extDict = matchCandidateIdx < dictLimit;
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const BYTE* const matchPtr = (extDict ? dictBase : base) + matchCandidateIdx;
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if (LZ4_read32(matchPtr) == pattern) { /* good candidate */
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const BYTE* const dictStart = dictBase + hc4->lowLimit;
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const BYTE* const iLimit = extDict ? dictBase + dictLimit : iHighLimit;
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size_t forwardPatternLength = LZ4HC_countPattern(matchPtr+sizeof(pattern), iLimit, pattern) + sizeof(pattern);
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if (extDict && matchPtr + forwardPatternLength == iLimit) {
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U32 const rotatedPattern = LZ4HC_rotatePattern(forwardPatternLength, pattern);
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forwardPatternLength += LZ4HC_countPattern(lowPrefixPtr, iHighLimit, rotatedPattern);
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}
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{ const BYTE* const lowestMatchPtr = extDict ? dictStart : lowPrefixPtr;
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size_t backLength = LZ4HC_reverseCountPattern(matchPtr, lowestMatchPtr, pattern);
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size_t currentSegmentLength;
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if (!extDict && matchPtr - backLength == lowPrefixPtr && hc4->lowLimit < dictLimit) {
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U32 const rotatedPattern = LZ4HC_rotatePattern((U32)(-(int)backLength), pattern);
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backLength += LZ4HC_reverseCountPattern(dictBase + dictLimit, dictStart, rotatedPattern);
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}
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/* Limit backLength not go further than lowestMatchIndex */
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backLength = matchCandidateIdx - MAX(matchCandidateIdx - (U32)backLength, lowestMatchIndex);
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assert(matchCandidateIdx - backLength >= lowestMatchIndex);
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currentSegmentLength = backLength + forwardPatternLength;
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/* Adjust to end of pattern if the source pattern fits, otherwise the beginning of the pattern */
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if ( (currentSegmentLength >= srcPatternLength) /* current pattern segment large enough to contain full srcPatternLength */
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&& (forwardPatternLength <= srcPatternLength) ) { /* haven't reached this position yet */
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U32 const newMatchIndex = matchCandidateIdx + (U32)forwardPatternLength - (U32)srcPatternLength; /* best position, full pattern, might be followed by more match */
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if (LZ4HC_protectDictEnd(dictLimit, newMatchIndex))
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matchIndex = newMatchIndex;
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else {
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/* Can only happen if started in the prefix */
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assert(newMatchIndex >= dictLimit - 3 && newMatchIndex < dictLimit && !extDict);
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matchIndex = dictLimit;
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}
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} else {
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U32 const newMatchIndex = matchCandidateIdx - (U32)backLength; /* farthest position in current segment, will find a match of length currentSegmentLength + maybe some back */
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if (!LZ4HC_protectDictEnd(dictLimit, newMatchIndex)) {
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assert(newMatchIndex >= dictLimit - 3 && newMatchIndex < dictLimit && !extDict);
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matchIndex = dictLimit;
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} else {
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matchIndex = newMatchIndex;
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if (lookBackLength==0) { /* no back possible */
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size_t const maxML = MIN(currentSegmentLength, srcPatternLength);
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if ((size_t)longest < maxML) {
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assert(base + matchIndex < ip);
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if (ip - (base+matchIndex) > LZ4_DISTANCE_MAX) break;
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assert(maxML < 2 GB);
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longest = (int)maxML;
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*matchpos = base + matchIndex; /* virtual pos, relative to ip, to retrieve offset */
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*startpos = ip;
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}
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{ U32 const distToNextPattern = DELTANEXTU16(chainTable, matchIndex);
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if (distToNextPattern > matchIndex) break; /* avoid overflow */
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matchIndex -= distToNextPattern;
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} } } } }
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continue;
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} }
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} } /* PA optimization */
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/* follow current chain */
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matchIndex -= DELTANEXTU16(chainTable, matchIndex + matchChainPos);
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} /* while ((matchIndex>=lowestMatchIndex) && (nbAttempts)) */
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if ( dict == usingDictCtxHc
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&& nbAttempts
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&& ipIndex - lowestMatchIndex < LZ4_DISTANCE_MAX) {
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size_t const dictEndOffset = (size_t)(dictCtx->end - dictCtx->base);
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U32 dictMatchIndex = dictCtx->hashTable[LZ4HC_hashPtr(ip)];
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assert(dictEndOffset <= 1 GB);
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matchIndex = dictMatchIndex + lowestMatchIndex - (U32)dictEndOffset;
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while (ipIndex - matchIndex <= LZ4_DISTANCE_MAX && nbAttempts--) {
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const BYTE* const matchPtr = dictCtx->base + dictMatchIndex;
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if (LZ4_read32(matchPtr) == pattern) {
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int mlt;
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int back = 0;
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const BYTE* vLimit = ip + (dictEndOffset - dictMatchIndex);
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if (vLimit > iHighLimit) vLimit = iHighLimit;
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mlt = (int)LZ4_count(ip+MINMATCH, matchPtr+MINMATCH, vLimit) + MINMATCH;
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back = lookBackLength ? LZ4HC_countBack(ip, matchPtr, iLowLimit, dictCtx->base + dictCtx->dictLimit) : 0;
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mlt -= back;
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if (mlt > longest) {
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|
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 */
|
|
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
|
|
**************************************/
|
|
/* allocation */
|
|
LZ4_streamHC_t* LZ4_createStreamHC(void)
|
|
{
|
|
LZ4_streamHC_t* const LZ4_streamHCPtr = (LZ4_streamHC_t*)ALLOC(sizeof(LZ4_streamHC_t));
|
|
if (LZ4_streamHCPtr==NULL) return NULL;
|
|
LZ4_initStreamHC(LZ4_streamHCPtr, sizeof(*LZ4_streamHCPtr)); /* full initialization, malloc'ed buffer can be full of garbage */
|
|
return LZ4_streamHCPtr;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
|
|
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 (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)
|
|
{
|
|
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;
|
|
}
|
|
|
|
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(%p, %p, %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 >= 4) 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->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;
|
|
}
|
|
|
|
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(4, "LZ4_compressHC_continue_generic(ctx=%p, src=%p, srcSize=%d)",
|
|
LZ4_streamHCPtr, src, *srcSizePtr);
|
|
assert(ctxPtr != NULL);
|
|
/* auto-init if forgotten */
|
|
if (ctxPtr->base == NULL) LZ4HC_init_internal (ctxPtr, (const BYTE*) src);
|
|
|
|
/* Check overflow */
|
|
if ((size_t)(ctxPtr->end - ctxPtr->base) > 2 GB) {
|
|
size_t dictSize = (size_t)(ctxPtr->end - ctxPtr->base) - ctxPtr->dictLimit;
|
|
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->dictBase + ctxPtr->lowLimit;
|
|
const BYTE* const dictEnd = ctxPtr->dictBase + ctxPtr->dictLimit;
|
|
if ((sourceEnd > dictBegin) && ((const BYTE*)src < dictEnd)) {
|
|
if (sourceEnd > dictEnd) sourceEnd = dictEnd;
|
|
ctxPtr->lowLimit = (U32)(sourceEnd - ctxPtr->dictBase);
|
|
if (ctxPtr->dictLimit - ctxPtr->lowLimit < 4) ctxPtr->lowLimit = ctxPtr->dictLimit;
|
|
}
|
|
}
|
|
|
|
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)
|
|
{
|
|
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);
|
|
}
|
|
|
|
|
|
|
|
/* dictionary saving */
|
|
|
|
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->base + streamPtr->dictLimit));
|
|
DEBUGLOG(4, "LZ4_saveDictHC(%p, %p, %d)", LZ4_streamHCPtr, safeBuffer, dictSize);
|
|
if (dictSize > 64 KB) dictSize = 64 KB;
|
|
if (dictSize < 4) dictSize = 0;
|
|
if (dictSize > prefixSize) dictSize = prefixSize;
|
|
memmove(safeBuffer, streamPtr->end - dictSize, dictSize);
|
|
{ U32 const endIndex = (U32)(streamPtr->end - streamPtr->base);
|
|
streamPtr->end = (const BYTE*)safeBuffer + dictSize;
|
|
streamPtr->base = streamPtr->end - endIndex;
|
|
streamPtr->dictLimit = endIndex - (U32)dictSize;
|
|
streamPtr->lowLimit = endIndex - (U32)dictSize;
|
|
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 LZ4_STREAMHCSIZE; }
|
|
|
|
/* 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;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
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)
|
|
{
|
|
LZ4_streamHC_t *ctx = (LZ4_streamHC_t*)LZ4HC_Data;
|
|
const BYTE *bufferStart = ctx->internal_donotuse.base + ctx->internal_donotuse.lowLimit;
|
|
LZ4_resetStreamHC_fast(ctx, ctx->internal_donotuse.compressionLevel);
|
|
/* avoid const char * -> char * conversion 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)
|
|
{
|
|
#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;
|
|
}
|