ddidderr/zstd-rs
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lazydeep

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This commit is contained in:
Yann Collet
2015-11-02 16:14:46 +01:00
parent ee34cdf33d
commit 3564487614
8 changed files with 156 additions and 23 deletions
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lib/zstd.h
+1 -1
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@@ -48,7 +48,7 @@ extern "C" {
***************************************/
#define ZSTD_VERSION_MAJOR 0 /* for breaking interface changes */
#define ZSTD_VERSION_MINOR 3 /* for new (non-breaking) interface capabilities */
#define ZSTD_VERSION_RELEASE 2 /* for tweaks, bug-fixes, or development */
#define ZSTD_VERSION_RELEASE 3 /* for tweaks, bug-fixes, or development */
#define ZSTD_VERSION_NUMBER (ZSTD_VERSION_MAJOR *100*100 + ZSTD_VERSION_MINOR *100 + ZSTD_VERSION_RELEASE)
unsigned ZSTD_versionNumber (void);
lib/zstdhc.c
+140 -10
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@@ -289,6 +289,127 @@ FORCE_INLINE size_t ZSTD_HC_insertAndFindBestMatch_selectMLS (
}
size_t ZSTD_HC_compressBlock_lazydeep(ZSTD_HC_CCtx* ctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize)
{
seqStore_t* seqStorePtr = &(ctx->seqStore);
const BYTE* const istart = (const BYTE*)src;
const BYTE* ip = istart;
const BYTE* anchor = istart;
const BYTE* const iend = istart + srcSize;
const BYTE* const ilimit = iend - 8;
const BYTE* match = istart;
size_t offset_2=REPCODE_STARTVALUE, offset_1=REPCODE_STARTVALUE;
const U32 maxSearches = 1 << ctx->params.searchLog;
const U32 mls = ctx->params.searchLength;
/* init */
ZSTD_resetSeqStore(seqStorePtr);
if (((ip-ctx->base) - ctx->dictLimit) < REPCODE_STARTVALUE) ip += REPCODE_STARTVALUE;
/* Match Loop */
while (ip <= ilimit)
{
size_t matchLength;
size_t offset;
const BYTE* start;
/* try to find a first match */
if (MEM_read32(ip) == MEM_read32(ip - offset_2))
{
/* repcode : we take it*/
size_t offtmp = offset_2;
size_t litLength = ip - anchor;
matchLength = ZSTD_count(ip+MINMATCH, ip+MINMATCH-offset_2, iend);
offset_2 = offset_1;
offset_1 = offtmp;
ZSTD_storeSeq(seqStorePtr, litLength, anchor, 0, matchLength);
ip += matchLength+MINMATCH;
anchor = ip;
continue;
}
offset_2 = offset_1;
matchLength = ZSTD_HC_insertAndFindBestMatch_selectMLS(ctx, ip, iend, &match, maxSearches, mls);
if (!matchLength) { ip++; continue; }
/* let's try to find a better solution */
offset = ip - match;
start = ip;
while (ip<ilimit)
{
ip ++;
if (MEM_read32(ip) == MEM_read32(ip - offset_1))
{
size_t ml2 = ZSTD_count(ip+MINMATCH, ip+MINMATCH-offset_1, iend) + MINMATCH;
int gain2 = (int)(ml2 * 3);
int gain1 = (int)(matchLength*3 - ZSTD_highbit((U32)offset+1) + 1);
if (gain2 > gain1)
matchLength = ml2, offset = 0, start = ip;
}
{
size_t ml2 = ZSTD_HC_insertAndFindBestMatch_selectMLS(ctx, ip, iend, &match, maxSearches, mls);
size_t offset2 = ip - match;
int gain2 = (int)(ml2*4 - ZSTD_highbit((U32)offset2+1)); /* raw approx */
int gain1 = (int)(matchLength*4 - ZSTD_highbit((U32)offset+1) + 4);
if (gain2 > gain1)
{
matchLength = ml2, offset = offset2, start = ip;
continue; /* search a better one */
}
}
if (ip<ilimit)
{
ip ++;
if (MEM_read32(ip) == MEM_read32(ip - offset_1))
{
size_t ml2 = ZSTD_count(ip+MINMATCH, ip+MINMATCH-offset_1, iend) + MINMATCH;
int gain2 = (int)(ml2 * 4);
int gain1 = (int)(matchLength*4 - ZSTD_highbit((U32)offset+1) + 2);
if (gain2 > gain1)
matchLength = ml2, offset = 0, start = ip;
}
{
size_t ml2 = ZSTD_HC_insertAndFindBestMatch_selectMLS(ctx, ip, iend, &match, maxSearches, mls);
size_t offset2 = ip - match;
int gain2 = (int)(ml2*4 - ZSTD_highbit((U32)offset2+1)); /* raw approx */
int gain1 = (int)(matchLength*4 - ZSTD_highbit((U32)offset+1) + 8);
if (gain2 > gain1)
{
matchLength = ml2, offset = offset2, start = ip;
continue;
}
}
}
break; /* nothing found : store previous one */
}
/* store sequence */
{
size_t litLength = start - anchor;
if (offset) offset_1 = offset;
ZSTD_storeSeq(seqStorePtr, litLength, anchor, offset, matchLength-MINMATCH);
ip = start + matchLength;
anchor = ip;
}
}
/* Last Literals */
{
size_t lastLLSize = iend - anchor;
memcpy(seqStorePtr->lit, anchor, lastLLSize);
seqStorePtr->lit += lastLLSize;
}
/* Final compression stage */
return ZSTD_compressSequences((BYTE*)dst, maxDstSize,
seqStorePtr, srcSize);
}
size_t ZSTD_HC_compressBlock_lazy(ZSTD_HC_CCtx* ctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize)
{
seqStore_t* seqStorePtr = &(ctx->seqStore);
@@ -343,19 +464,19 @@ size_t ZSTD_HC_compressBlock_lazy(ZSTD_HC_CCtx* ctx, void* dst, size_t maxDstSiz
if (MEM_read32(ip) == MEM_read32(ip - offset_1))
{
size_t ml2 = ZSTD_count(ip+MINMATCH, ip+MINMATCH-offset_1, iend) + MINMATCH;
int gain2 = (int)(ml2 * 4);
int gain1 = (int)(matchLength*4 - ZSTD_highbit((U32)offset));
int gain2 = (int)(ml2 * 3);
int gain1 = (int)(matchLength*3 - ZSTD_highbit((U32)offset+1) + 1);
if (gain2 > gain1)
{
matchLength = ml2, offset = 0, start = ip;
break;
}
}
{
size_t ml2 = ZSTD_HC_insertAndFindBestMatch_selectMLS(ctx, ip, iend, &match, maxSearches, mls);
size_t offset2 = ip - match;
int gain2 = (int)(ml2*5 - ZSTD_highbit((U32)offset2)); /* raw approx */
int gain1 = (int)(matchLength*5 - ZSTD_highbit((U32)offset));
int gain2 = (int)(ml2*3 - ZSTD_highbit((U32)offset2+1)); /* raw approx */
int gain1 = (int)(matchLength*3 - ZSTD_highbit((U32)offset+1) + 3);
if (gain2 > gain1)
{
matchLength = ml2, offset = offset2, start = ip;
@@ -488,11 +609,20 @@ static size_t ZSTD_HC_compress_generic (ZSTD_HC_CCtx* ctxPtr,
BYTE* const oend = op + maxDstSize;
size_t (*blockCompressor) (ZSTD_HC_CCtx* ctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize);
if (ctxPtr->params.strategy == ZSTD_HC_greedy)
blockCompressor = ZSTD_HC_compressBlock_greedy;
else
blockCompressor = ZSTD_HC_compressBlock_lazy;
switch(ctxPtr->params.strategy)
{
case ZSTD_HC_greedy:
blockCompressor = ZSTD_HC_compressBlock_greedy;
break;
case ZSTD_HC_lazy:
blockCompressor = ZSTD_HC_compressBlock_lazy;
break;
case ZSTD_HC_lazydeep:
blockCompressor = ZSTD_HC_compressBlock_lazydeep;
break;
default :
return ERROR(GENERIC); /* unknown block compressor */
}
while (remaining > blockSize)
{
lib/zstdhc_static.h
+1 -1
View File
@@ -45,7 +45,7 @@ extern "C" {
/* *************************************
* Types
***************************************/
typedef enum { ZSTD_HC_greedy, ZSTD_HC_lazy } ZSTD_HC_strategy;
typedef enum { ZSTD_HC_greedy, ZSTD_HC_lazy, ZSTD_HC_lazydeep } ZSTD_HC_strategy;
typedef struct
{
U32 windowLog; /* largest match distance : impact decompression buffer size */