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This commit is contained in:
Yann Collet 2015-11-23 14:23:47 +01:00
parent 5054ee0cc0
commit 06eade5102
1 changed files with 25 additions and 21 deletions
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46
lib/zstd_compress.c
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@ -765,7 +765,7 @@ size_t ZSTD_compressBlock_fast_generic(ZSTD_CCtx* ctx,
const BYTE* match = base + hashTable[h];
hashTable[h] = (U32)(ip-base);
if (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1))
if (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1)) /* note : by construction, offset_1 <= (ip-base) */
{
mlCode = ZSTD_count(ip+1+MINMATCH, ip+1+MINMATCH-offset_1, iend);
ip++;
@ -773,7 +773,7 @@ size_t ZSTD_compressBlock_fast_generic(ZSTD_CCtx* ctx,
}
else
{
if ( (match < lowest) ||
if ( (match <= lowest) ||
(MEM_read32(match) != MEM_read32(ip)) )
{
ip += ((ip-anchor) >> g_searchStrength) + 1;
@ -801,11 +801,11 @@ size_t ZSTD_compressBlock_fast_generic(ZSTD_CCtx* ctx,
&& (MEM_read32(ip) == MEM_read32(ip - offset_2)) )
{
/* store sequence */
size_t ml = ZSTD_count(ip+MINMATCH, ip+MINMATCH-offset_2, iend);
size_t rlCode = ZSTD_count(ip+MINMATCH, ip+MINMATCH-offset_2, iend);
size_t tmpOff = offset_2; offset_2 = offset_1; offset_1 = tmpOff; /* swap offset_2 <=> offset_1 */
hashTable[ZSTD_hashPtr(ip, hBits, mls)] = (U32)(ip-base);
ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, ml);
ip += ml+MINMATCH;
ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, rlCode);
ip += rlCode+MINMATCH;
anchor = ip;
continue; /* faster when present ... (?) */
}
@ -989,8 +989,9 @@ size_t ZSTD_compressBlock_fast_extDict(ZSTD_CCtx* ctx,
/* *************************************
* Binary Tree search
***************************************/
/** ZSTD_insertBt1 : add one ptr to tree
@ip : assumed <= iend-8 */
/** ZSTD_insertBt1 : add one or multiple positions to tree
* @ip : assumed <= iend-8
* @return : nb of positions added */
static U32 ZSTD_insertBt1(ZSTD_CCtx* zc, const BYTE* const ip, const U32 mls, const BYTE* const iend, U32 nbCompares)
{
U32* const hashTable = zc->hashTable;
@ -1011,10 +1012,10 @@ static U32 ZSTD_insertBt1(ZSTD_CCtx* zc, const BYTE* const ip, const U32 mls, co
const U32 windowSize = 1 << zc->params.windowLog;
const U32 windowLow = windowSize >= current ? 0 : current - windowSize;
if ((current-matchIndex == 1) /* RLE */
&& MEM_read64(match) == MEM_read64(ip))
if ( (current-matchIndex == 1) /* RLE */
&& (MEM_read64(match) == MEM_read64(ip)) )
{
size_t rleLength = ZSTD_count(ip+sizeof(size_t), match+sizeof(size_t), iend) + sizeof(size_t);
size_t rleLength = ZSTD_count(ip+8, match+8, iend) + 8;
return (U32)(rleLength - mls);
}
@ -1030,7 +1031,7 @@ static U32 ZSTD_insertBt1(ZSTD_CCtx* zc, const BYTE* const ip, const U32 mls, co
matchLength += ZSTD_count(ip+matchLength+1, match+matchLength+1, iend) +1;
if (ip+matchLength == iend) /* equal : no way to know if inf or sup */
break; /* just drop , to guarantee consistency (miss a bit of compression; if someone knows better, please tell) */
break; /* drop , to guarantee consistency ; miss a bit of compression, but other solutions can corrupt the tree */
if (match[matchLength] < ip[matchLength])
{
@ -1133,7 +1134,6 @@ static const BYTE* ZSTD_updateTree(ZSTD_CCtx* zc, const BYTE* const ip, const BY
const BYTE* const base = zc->base;
const U32 target = (U32)(ip - base);
U32 idx = zc->nextToUpdate;
//size_t dummy;
for( ; idx < target ; )
idx += ZSTD_insertBt1(zc, base+idx, mls, iend, nbCompares);
@ -1152,12 +1152,8 @@ size_t ZSTD_BtFindBestMatch (
const U32 maxNbAttempts, const U32 mls)
{
const BYTE* nextToUpdate = ZSTD_updateTree(zc, ip, iLimit, maxNbAttempts, mls);
if (nextToUpdate > ip)
{
/* RLE data */
*offsetPtr = 1;
return ZSTD_count(ip, ip-1, iLimit);
}
if (nextToUpdate > ip) /* RLE data */
{ *offsetPtr = 1; return ZSTD_count(ip, ip-1, iLimit); }
return ZSTD_insertBtAndFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls);
}
@ -1184,8 +1180,9 @@ FORCE_INLINE size_t ZSTD_BtFindBestMatch_selectMLS (
#define NEXT_IN_CHAIN(d, mask) chainTable[(d) & mask]
/* Update chains up to ip (excluded) */
static U32 ZSTD_insertAndFindFirstIndex (ZSTD_CCtx* zc, const BYTE* ip, U32 mls)
/* Update chains up to ip (excluded)
Assumption : always within prefix (ie. not within extDict) */
static U32 ZSTD_insertAndFindFirstIndex (ZSTD_CCtx* zc, const BYTE* ip, U32 mls)
{
U32* const hashTable = zc->hashTable;
const U32 hashLog = zc->params.hashLog;
@ -1221,7 +1218,7 @@ size_t ZSTD_HcFindBestMatch (
const U32 chainSize = (1 << zc->params.contentLog);
const U32 minChain = current > chainSize ? current - chainSize : 0;
const U32 chainMask = chainSize-1;
const U32 lowLimit = zc->dictLimit; /* should be equal to zc->lowLimit, but safer use this one if they are not since dictLimit >= lowLimit */
const U32 lowLimit = zc->dictLimit; /* should be == zc->lowLimit, but safer to use this one if they are not, since dictLimit >= lowLimit */
U32 matchIndex;
const BYTE* match;
int nbAttempts=maxNbAttempts;
@ -1252,6 +1249,13 @@ size_t ZSTD_HcFindBestMatch (
return ml;
}
FORCE_INLINE /* inlining is important to hardwire a hot branch (template emulation) */
size_t ZSTD_HcFindBestMatch_extDict (
ZSTD_CCtx* zc, /* Index table will be updated */
const BYTE* const ip, const BYTE* const iLimit,
size_t* offsetPtr,
const U32 maxNbAttempts, const U32 matchLengthSearch);
FORCE_INLINE size_t ZSTD_HcFindBestMatch_selectMLS (
ZSTD_CCtx* zc, /* Index table will be updated */
const BYTE* ip, const BYTE* const iLimit,