ddidderr/zstd-rs
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This commit is contained in:
Yann Collet
2015-10-26 17:44:04 +01:00
parent 786f5b554a
commit 342892c3ae
1 changed files with 19 additions and 9 deletions
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lib/zstdhc.c
+19 -9
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@@ -103,7 +103,7 @@ size_t ZSTD_HC_freeCCtx(ZSTD_HC_CCtx* cctx)
static void ZSTD_HC_resetCCtx_advanced (ZSTD_HC_CCtx* zc, static void ZSTD_HC_resetCCtx_advanced (ZSTD_HC_CCtx* zc,
const ZSTD_HC_parameters params, const void* start) const ZSTD_HC_parameters params, const void* start)
{ {
U32 maxDistance = ( 1 << params.searchLog) + 1; U32 outOfReach = ( 1 << params.searchLog) + 1;
if (zc->hashTableLog < params.hashLog) if (zc->hashTableLog < params.hashLog)
{ {
@@ -121,12 +121,12 @@ static void ZSTD_HC_resetCCtx_advanced (ZSTD_HC_CCtx* zc,
} }
memset(zc->chainTable, 0, (1 << params.chainLog) * sizeof(U32) ); memset(zc->chainTable, 0, (1 << params.chainLog) * sizeof(U32) );
zc->nextToUpdate = maxDistance; zc->nextToUpdate = outOfReach;
zc->end = (const BYTE*)start; zc->end = (const BYTE*)start;
zc->base = zc->end - maxDistance; zc->base = zc->end - outOfReach;
zc->dictBase = zc->base; zc->dictBase = zc->base;
zc->dictLimit = maxDistance; zc->dictLimit = outOfReach;
zc->lowLimit = maxDistance; zc->lowLimit = outOfReach;
zc->params = params; zc->params = params;
zc->seqStore.buffer = zc->buffer; zc->seqStore.buffer = zc->buffer;
zc->seqStore.offsetStart = (U32*) (zc->seqStore.buffer); zc->seqStore.offsetStart = (U32*) (zc->seqStore.buffer);
@@ -259,7 +259,7 @@ static size_t ZSTD_HC_compressBlock(ZSTD_HC_CCtx* ctx, void* dst, size_t maxDstS
if (MEM_read32(ip) == MEM_read32(ip - offset_2)) if (MEM_read32(ip) == MEM_read32(ip - offset_2))
/* store sequence */ /* store sequence */
{ {
size_t matchLength = ZSTD_count(ip+4, ip+4-offset_2, iend); size_t matchLength = ZSTD_count(ip+MINMATCH, ip+MINMATCH-offset_2, iend);
size_t litLength = ip-anchor; size_t litLength = ip-anchor;
size_t offset = offset_2; size_t offset = offset_2;
offset_2 = offset_1; offset_2 = offset_1;
@@ -270,6 +270,18 @@ static size_t ZSTD_HC_compressBlock(ZSTD_HC_CCtx* ctx, void* dst, size_t maxDstS
continue; continue;
} }
/* repcode at ip+1 */
if (MEM_read32(ip+1) == MEM_read32(ip+1 - offset_1))
{
size_t matchLength = ZSTD_count(ip+1+MINMATCH, ip+1+MINMATCH-offset_1, iend);
size_t litLength = ip+1-anchor;
offset_2 = offset_1;
ZSTD_storeSeq(seqStorePtr, litLength, anchor, 0, matchLength);
ip += 1+matchLength+MINMATCH;
anchor = ip;
continue;
}
/* search */ /* search */
{ {
const BYTE* match; const BYTE* match;
@@ -278,11 +290,9 @@ static size_t ZSTD_HC_compressBlock(ZSTD_HC_CCtx* ctx, void* dst, size_t maxDstS
/* store sequence */ /* store sequence */
{ {
size_t litLength = ip-anchor; size_t litLength = ip-anchor;
size_t offset = ip-match;
if (offset == offset_2) offset = 0;
offset_2 = offset_1; offset_2 = offset_1;
offset_1 = ip-match; offset_1 = ip-match;
ZSTD_storeSeq(seqStorePtr, litLength, anchor, offset, matchLength-MINMATCH); ZSTD_storeSeq(seqStorePtr, litLength, anchor, offset_1, matchLength-MINMATCH);
ip += matchLength; ip += matchLength;
anchor = ip; anchor = ip;
} }