mirror of
https://github.com/facebook/zstd.git
synced 2025-10-31 00:04:03 -04:00
ee441d5d2b
to emphasize the fact that all definitions it contains must remain private, accross lib/compress modules.
310 lines
14 KiB
C
310 lines
14 KiB
C
/*
|
|
* Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
|
|
* All rights reserved.
|
|
*
|
|
* This source code is licensed under both the BSD-style license (found in the
|
|
* LICENSE file in the root directory of this source tree) and the GPLv2 (found
|
|
* in the COPYING file in the root directory of this source tree).
|
|
* You may select, at your option, one of the above-listed licenses.
|
|
*/
|
|
|
|
#include "zstd_compress_internal.h"
|
|
#include "zstd_double_fast.h"
|
|
|
|
|
|
void ZSTD_fillDoubleHashTable(ZSTD_CCtx* cctx, const void* end, const U32 mls)
|
|
{
|
|
U32* const hashLarge = cctx->hashTable;
|
|
U32 const hBitsL = cctx->appliedParams.cParams.hashLog;
|
|
U32* const hashSmall = cctx->chainTable;
|
|
U32 const hBitsS = cctx->appliedParams.cParams.chainLog;
|
|
const BYTE* const base = cctx->base;
|
|
const BYTE* ip = base + cctx->nextToUpdate;
|
|
const BYTE* const iend = ((const BYTE*)end) - HASH_READ_SIZE;
|
|
const size_t fastHashFillStep = 3;
|
|
|
|
while(ip <= iend) {
|
|
hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = (U32)(ip - base);
|
|
hashLarge[ZSTD_hashPtr(ip, hBitsL, 8)] = (U32)(ip - base);
|
|
ip += fastHashFillStep;
|
|
}
|
|
}
|
|
|
|
|
|
FORCE_INLINE_TEMPLATE
|
|
size_t ZSTD_compressBlock_doubleFast_generic(ZSTD_CCtx* cctx,
|
|
const void* src, size_t srcSize,
|
|
const U32 mls)
|
|
{
|
|
U32* const hashLong = cctx->hashTable;
|
|
const U32 hBitsL = cctx->appliedParams.cParams.hashLog;
|
|
U32* const hashSmall = cctx->chainTable;
|
|
const U32 hBitsS = cctx->appliedParams.cParams.chainLog;
|
|
seqStore_t* seqStorePtr = &(cctx->seqStore);
|
|
const BYTE* const base = cctx->base;
|
|
const BYTE* const istart = (const BYTE*)src;
|
|
const BYTE* ip = istart;
|
|
const BYTE* anchor = istart;
|
|
const U32 lowestIndex = cctx->dictLimit;
|
|
const BYTE* const lowest = base + lowestIndex;
|
|
const BYTE* const iend = istart + srcSize;
|
|
const BYTE* const ilimit = iend - HASH_READ_SIZE;
|
|
U32 offset_1=seqStorePtr->rep[0], offset_2=seqStorePtr->rep[1];
|
|
U32 offsetSaved = 0;
|
|
|
|
/* init */
|
|
ip += (ip==lowest);
|
|
{ U32 const maxRep = (U32)(ip-lowest);
|
|
if (offset_2 > maxRep) offsetSaved = offset_2, offset_2 = 0;
|
|
if (offset_1 > maxRep) offsetSaved = offset_1, offset_1 = 0;
|
|
}
|
|
|
|
/* Main Search Loop */
|
|
while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */
|
|
size_t mLength;
|
|
size_t const h2 = ZSTD_hashPtr(ip, hBitsL, 8);
|
|
size_t const h = ZSTD_hashPtr(ip, hBitsS, mls);
|
|
U32 const current = (U32)(ip-base);
|
|
U32 const matchIndexL = hashLong[h2];
|
|
U32 const matchIndexS = hashSmall[h];
|
|
const BYTE* matchLong = base + matchIndexL;
|
|
const BYTE* match = base + matchIndexS;
|
|
hashLong[h2] = hashSmall[h] = current; /* update hash tables */
|
|
|
|
assert(offset_1 <= current); /* supposed guaranteed by construction */
|
|
if ((offset_1 > 0) & (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1))) {
|
|
/* favor repcode */
|
|
mLength = ZSTD_count(ip+1+4, ip+1+4-offset_1, iend) + 4;
|
|
ip++;
|
|
ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, 0, mLength-MINMATCH);
|
|
} else {
|
|
U32 offset;
|
|
if ( (matchIndexL > lowestIndex) && (MEM_read64(matchLong) == MEM_read64(ip)) ) {
|
|
mLength = ZSTD_count(ip+8, matchLong+8, iend) + 8;
|
|
offset = (U32)(ip-matchLong);
|
|
while (((ip>anchor) & (matchLong>lowest)) && (ip[-1] == matchLong[-1])) { ip--; matchLong--; mLength++; } /* catch up */
|
|
} else if ( (matchIndexS > lowestIndex) && (MEM_read32(match) == MEM_read32(ip)) ) {
|
|
size_t const hl3 = ZSTD_hashPtr(ip+1, hBitsL, 8);
|
|
U32 const matchIndexL3 = hashLong[hl3];
|
|
const BYTE* matchL3 = base + matchIndexL3;
|
|
hashLong[hl3] = current + 1;
|
|
if ( (matchIndexL3 > lowestIndex) && (MEM_read64(matchL3) == MEM_read64(ip+1)) ) {
|
|
mLength = ZSTD_count(ip+9, matchL3+8, iend) + 8;
|
|
ip++;
|
|
offset = (U32)(ip-matchL3);
|
|
while (((ip>anchor) & (matchL3>lowest)) && (ip[-1] == matchL3[-1])) { ip--; matchL3--; mLength++; } /* catch up */
|
|
} else {
|
|
mLength = ZSTD_count(ip+4, match+4, iend) + 4;
|
|
offset = (U32)(ip-match);
|
|
while (((ip>anchor) & (match>lowest)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
|
|
}
|
|
} else {
|
|
ip += ((ip-anchor) >> g_searchStrength) + 1;
|
|
continue;
|
|
}
|
|
|
|
offset_2 = offset_1;
|
|
offset_1 = offset;
|
|
|
|
ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
|
|
}
|
|
|
|
/* match found */
|
|
ip += mLength;
|
|
anchor = ip;
|
|
|
|
if (ip <= ilimit) {
|
|
/* Fill Table */
|
|
hashLong[ZSTD_hashPtr(base+current+2, hBitsL, 8)] =
|
|
hashSmall[ZSTD_hashPtr(base+current+2, hBitsS, mls)] = current+2; /* here because current+2 could be > iend-8 */
|
|
hashLong[ZSTD_hashPtr(ip-2, hBitsL, 8)] =
|
|
hashSmall[ZSTD_hashPtr(ip-2, hBitsS, mls)] = (U32)(ip-2-base);
|
|
|
|
/* check immediate repcode */
|
|
while ( (ip <= ilimit)
|
|
&& ( (offset_2>0)
|
|
& (MEM_read32(ip) == MEM_read32(ip - offset_2)) )) {
|
|
/* store sequence */
|
|
size_t const rLength = ZSTD_count(ip+4, ip+4-offset_2, iend) + 4;
|
|
{ U32 const tmpOff = offset_2; offset_2 = offset_1; offset_1 = tmpOff; } /* swap offset_2 <=> offset_1 */
|
|
hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = (U32)(ip-base);
|
|
hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = (U32)(ip-base);
|
|
ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, rLength-MINMATCH);
|
|
ip += rLength;
|
|
anchor = ip;
|
|
continue; /* faster when present ... (?) */
|
|
} } }
|
|
|
|
/* save reps for next block */
|
|
seqStorePtr->repToConfirm[0] = offset_1 ? offset_1 : offsetSaved;
|
|
seqStorePtr->repToConfirm[1] = offset_2 ? offset_2 : offsetSaved;
|
|
|
|
/* Return the last literals size */
|
|
return iend - anchor;
|
|
}
|
|
|
|
|
|
size_t ZSTD_compressBlock_doubleFast(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
|
|
{
|
|
const U32 mls = ctx->appliedParams.cParams.searchLength;
|
|
switch(mls)
|
|
{
|
|
default: /* includes case 3 */
|
|
case 4 :
|
|
return ZSTD_compressBlock_doubleFast_generic(ctx, src, srcSize, 4);
|
|
case 5 :
|
|
return ZSTD_compressBlock_doubleFast_generic(ctx, src, srcSize, 5);
|
|
case 6 :
|
|
return ZSTD_compressBlock_doubleFast_generic(ctx, src, srcSize, 6);
|
|
case 7 :
|
|
return ZSTD_compressBlock_doubleFast_generic(ctx, src, srcSize, 7);
|
|
}
|
|
}
|
|
|
|
|
|
static size_t ZSTD_compressBlock_doubleFast_extDict_generic(ZSTD_CCtx* ctx,
|
|
const void* src, size_t srcSize,
|
|
const U32 mls)
|
|
{
|
|
U32* const hashLong = ctx->hashTable;
|
|
U32 const hBitsL = ctx->appliedParams.cParams.hashLog;
|
|
U32* const hashSmall = ctx->chainTable;
|
|
U32 const hBitsS = ctx->appliedParams.cParams.chainLog;
|
|
seqStore_t* seqStorePtr = &(ctx->seqStore);
|
|
const BYTE* const base = ctx->base;
|
|
const BYTE* const dictBase = ctx->dictBase;
|
|
const BYTE* const istart = (const BYTE*)src;
|
|
const BYTE* ip = istart;
|
|
const BYTE* anchor = istart;
|
|
const U32 lowestIndex = ctx->lowLimit;
|
|
const BYTE* const dictStart = dictBase + lowestIndex;
|
|
const U32 dictLimit = ctx->dictLimit;
|
|
const BYTE* const lowPrefixPtr = base + dictLimit;
|
|
const BYTE* const dictEnd = dictBase + dictLimit;
|
|
const BYTE* const iend = istart + srcSize;
|
|
const BYTE* const ilimit = iend - 8;
|
|
U32 offset_1=seqStorePtr->rep[0], offset_2=seqStorePtr->rep[1];
|
|
|
|
/* Search Loop */
|
|
while (ip < ilimit) { /* < instead of <=, because (ip+1) */
|
|
const size_t hSmall = ZSTD_hashPtr(ip, hBitsS, mls);
|
|
const U32 matchIndex = hashSmall[hSmall];
|
|
const BYTE* matchBase = matchIndex < dictLimit ? dictBase : base;
|
|
const BYTE* match = matchBase + matchIndex;
|
|
|
|
const size_t hLong = ZSTD_hashPtr(ip, hBitsL, 8);
|
|
const U32 matchLongIndex = hashLong[hLong];
|
|
const BYTE* matchLongBase = matchLongIndex < dictLimit ? dictBase : base;
|
|
const BYTE* matchLong = matchLongBase + matchLongIndex;
|
|
|
|
const U32 current = (U32)(ip-base);
|
|
const U32 repIndex = current + 1 - offset_1; /* offset_1 expected <= current +1 */
|
|
const BYTE* repBase = repIndex < dictLimit ? dictBase : base;
|
|
const BYTE* repMatch = repBase + repIndex;
|
|
size_t mLength;
|
|
hashSmall[hSmall] = hashLong[hLong] = current; /* update hash table */
|
|
|
|
if ( (((U32)((dictLimit-1) - repIndex) >= 3) /* intentional underflow */ & (repIndex > lowestIndex))
|
|
&& (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
|
|
const BYTE* repMatchEnd = repIndex < dictLimit ? dictEnd : iend;
|
|
mLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, lowPrefixPtr) + 4;
|
|
ip++;
|
|
ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, 0, mLength-MINMATCH);
|
|
} else {
|
|
if ((matchLongIndex > lowestIndex) && (MEM_read64(matchLong) == MEM_read64(ip))) {
|
|
const BYTE* matchEnd = matchLongIndex < dictLimit ? dictEnd : iend;
|
|
const BYTE* lowMatchPtr = matchLongIndex < dictLimit ? dictStart : lowPrefixPtr;
|
|
U32 offset;
|
|
mLength = ZSTD_count_2segments(ip+8, matchLong+8, iend, matchEnd, lowPrefixPtr) + 8;
|
|
offset = current - matchLongIndex;
|
|
while (((ip>anchor) & (matchLong>lowMatchPtr)) && (ip[-1] == matchLong[-1])) { ip--; matchLong--; mLength++; } /* catch up */
|
|
offset_2 = offset_1;
|
|
offset_1 = offset;
|
|
ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
|
|
|
|
} else if ((matchIndex > lowestIndex) && (MEM_read32(match) == MEM_read32(ip))) {
|
|
size_t const h3 = ZSTD_hashPtr(ip+1, hBitsL, 8);
|
|
U32 const matchIndex3 = hashLong[h3];
|
|
const BYTE* const match3Base = matchIndex3 < dictLimit ? dictBase : base;
|
|
const BYTE* match3 = match3Base + matchIndex3;
|
|
U32 offset;
|
|
hashLong[h3] = current + 1;
|
|
if ( (matchIndex3 > lowestIndex) && (MEM_read64(match3) == MEM_read64(ip+1)) ) {
|
|
const BYTE* matchEnd = matchIndex3 < dictLimit ? dictEnd : iend;
|
|
const BYTE* lowMatchPtr = matchIndex3 < dictLimit ? dictStart : lowPrefixPtr;
|
|
mLength = ZSTD_count_2segments(ip+9, match3+8, iend, matchEnd, lowPrefixPtr) + 8;
|
|
ip++;
|
|
offset = current+1 - matchIndex3;
|
|
while (((ip>anchor) & (match3>lowMatchPtr)) && (ip[-1] == match3[-1])) { ip--; match3--; mLength++; } /* catch up */
|
|
} else {
|
|
const BYTE* matchEnd = matchIndex < dictLimit ? dictEnd : iend;
|
|
const BYTE* lowMatchPtr = matchIndex < dictLimit ? dictStart : lowPrefixPtr;
|
|
mLength = ZSTD_count_2segments(ip+4, match+4, iend, matchEnd, lowPrefixPtr) + 4;
|
|
offset = current - matchIndex;
|
|
while (((ip>anchor) & (match>lowMatchPtr)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */
|
|
}
|
|
offset_2 = offset_1;
|
|
offset_1 = offset;
|
|
ZSTD_storeSeq(seqStorePtr, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH);
|
|
|
|
} else {
|
|
ip += ((ip-anchor) >> g_searchStrength) + 1;
|
|
continue;
|
|
} }
|
|
|
|
/* found a match : store it */
|
|
ip += mLength;
|
|
anchor = ip;
|
|
|
|
if (ip <= ilimit) {
|
|
/* Fill Table */
|
|
hashSmall[ZSTD_hashPtr(base+current+2, hBitsS, mls)] = current+2;
|
|
hashLong[ZSTD_hashPtr(base+current+2, hBitsL, 8)] = current+2;
|
|
hashSmall[ZSTD_hashPtr(ip-2, hBitsS, mls)] = (U32)(ip-2-base);
|
|
hashLong[ZSTD_hashPtr(ip-2, hBitsL, 8)] = (U32)(ip-2-base);
|
|
/* check immediate repcode */
|
|
while (ip <= ilimit) {
|
|
U32 const current2 = (U32)(ip-base);
|
|
U32 const repIndex2 = current2 - offset_2;
|
|
const BYTE* repMatch2 = repIndex2 < dictLimit ? dictBase + repIndex2 : base + repIndex2;
|
|
if ( (((U32)((dictLimit-1) - repIndex2) >= 3) & (repIndex2 > lowestIndex)) /* intentional overflow */
|
|
&& (MEM_read32(repMatch2) == MEM_read32(ip)) ) {
|
|
const BYTE* const repEnd2 = repIndex2 < dictLimit ? dictEnd : iend;
|
|
size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, lowPrefixPtr) + 4;
|
|
U32 tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */
|
|
ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, repLength2-MINMATCH);
|
|
hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = current2;
|
|
hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = current2;
|
|
ip += repLength2;
|
|
anchor = ip;
|
|
continue;
|
|
}
|
|
break;
|
|
} } }
|
|
|
|
/* save reps for next block */
|
|
seqStorePtr->repToConfirm[0] = offset_1; seqStorePtr->repToConfirm[1] = offset_2;
|
|
|
|
/* Return the last literals size */
|
|
return iend - anchor;
|
|
}
|
|
|
|
|
|
size_t ZSTD_compressBlock_doubleFast_extDict(ZSTD_CCtx* ctx,
|
|
const void* src, size_t srcSize)
|
|
{
|
|
U32 const mls = ctx->appliedParams.cParams.searchLength;
|
|
switch(mls)
|
|
{
|
|
default: /* includes case 3 */
|
|
case 4 :
|
|
return ZSTD_compressBlock_doubleFast_extDict_generic(ctx, src, srcSize, 4);
|
|
case 5 :
|
|
return ZSTD_compressBlock_doubleFast_extDict_generic(ctx, src, srcSize, 5);
|
|
case 6 :
|
|
return ZSTD_compressBlock_doubleFast_extDict_generic(ctx, src, srcSize, 6);
|
|
case 7 :
|
|
return ZSTD_compressBlock_doubleFast_extDict_generic(ctx, src, srcSize, 7);
|
|
}
|
|
}
|