From: Yann Collet Date: Fri, 1 Jan 2016 06:47:58 +0000 (+0100) Subject: minor refactoring X-Git-Tag: v0.4.6~2^2~14 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2cc12cb3cbe84e73741c95ac6e9c69a816e6533f;p=thirdparty%2Fzstd.git minor refactoring --- diff --git a/lib/zstd_compress.c b/lib/zstd_compress.c index 51157306b..0bb04ea02 100644 --- a/lib/zstd_compress.c +++ b/lib/zstd_compress.c @@ -1093,12 +1093,23 @@ static U32 ZSTD_insertBt1(ZSTD_CCtx* zc, const BYTE* const ip, const U32 mls, co } +static void ZSTD_updateTree(ZSTD_CCtx* zc, const BYTE* const ip, const BYTE* const iend, const U32 nbCompares, const U32 mls) +{ + const BYTE* const base = zc->base; + const U32 target = (U32)(ip - base); + U32 idx = zc->nextToUpdate; + + for( ; idx < target ; ) + idx += ZSTD_insertBt1(zc, base+idx, mls, iend, nbCompares, 0); +} + FORCE_INLINE /* inlining is important to hardwire a hot branch (template emulation) */ size_t ZSTD_insertBtAndFindBestMatch ( ZSTD_CCtx* zc, const BYTE* const ip, const BYTE* const iend, size_t* offsetPtr, - U32 nbCompares, const U32 mls) + U32 nbCompares, const U32 mls, + U32 extDict) { U32* const hashTable = zc->hashTable; const U32 hashLog = zc->params.hashLog; @@ -1109,6 +1120,10 @@ size_t ZSTD_insertBtAndFindBestMatch ( U32 matchIndex = hashTable[h]; size_t commonLengthSmaller=0, commonLengthLarger=0; const BYTE* const base = zc->base; + const BYTE* const dictBase = zc->dictBase; + const U32 dictLimit = zc->dictLimit; + const BYTE* const dictEnd = dictBase + dictLimit; + const BYTE* const prefixStart = base + dictLimit; const U32 current = (U32)(ip-base); const U32 btLow = btMask >= current ? 0 : current - btMask; const U32 windowLow = zc->lowLimit; @@ -1123,11 +1138,22 @@ size_t ZSTD_insertBtAndFindBestMatch ( while (nbCompares-- && (matchIndex > windowLow)) { U32* nextPtr = bt + 2*(matchIndex & btMask); - const BYTE* match = base + matchIndex; size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */ + const BYTE* match; - if (match[matchLength] == ip[matchLength]) - matchLength += ZSTD_count(ip+matchLength+1, match+matchLength+1, iend) +1; + if ((!extDict) || (matchIndex+matchLength >= dictLimit)) + { + match = base + matchIndex; + if (match[matchLength] == ip[matchLength]) + matchLength += ZSTD_count(ip+matchLength+1, match+matchLength+1, iend) +1; + } + else + { + match = dictBase + matchIndex; + matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart); + if (matchIndex+matchLength >= dictLimit) + match = base + matchIndex; /* to prepare for next usage of match[matchLength] */ + } if (matchLength > bestLength) { @@ -1166,17 +1192,6 @@ size_t ZSTD_insertBtAndFindBestMatch ( } -static void ZSTD_updateTree(ZSTD_CCtx* zc, const BYTE* const ip, const BYTE* const iend, const U32 nbCompares, const U32 mls) -{ - const BYTE* const base = zc->base; - const U32 target = (U32)(ip - base); - U32 idx = zc->nextToUpdate; - - for( ; idx < target ; ) - idx += ZSTD_insertBt1(zc, base+idx, mls, iend, nbCompares, 0); -} - - /** Tree updater, providing best match */ FORCE_INLINE /* inlining is important to hardwire a hot branch (template emulation) */ size_t ZSTD_BtFindBestMatch ( @@ -1187,7 +1202,7 @@ size_t ZSTD_BtFindBestMatch ( { if (ip < zc->base + zc->nextToUpdate) return 0; /* skipped area */ ZSTD_updateTree(zc, ip, iLimit, maxNbAttempts, mls); - return ZSTD_insertBtAndFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls); + return ZSTD_insertBtAndFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls, 0); } @@ -1218,93 +1233,6 @@ static void ZSTD_updateTree_extDict(ZSTD_CCtx* zc, const BYTE* const ip, const B } -FORCE_INLINE /* inlining is important to hardwire a hot branch (template emulation) */ -size_t ZSTD_insertBtAndFindBestMatch_extDict ( - ZSTD_CCtx* zc, - const BYTE* const ip, const BYTE* const iend, - size_t* offsetPtr, - U32 nbCompares, const U32 mls) -{ - U32* const hashTable = zc->hashTable; - const U32 hashLog = zc->params.hashLog; - const size_t h = ZSTD_hashPtr(ip, hashLog, mls); - U32* const bt = zc->contentTable; - const U32 btLog = zc->params.contentLog - 1; - const U32 btMask= (1 << btLog) - 1; - U32 matchIndex = hashTable[h]; - size_t commonLengthSmaller=0, commonLengthLarger=0; - const BYTE* const base = zc->base; - const BYTE* const dictBase = zc->dictBase; - const U32 dictLimit = zc->dictLimit; - const BYTE* const dictEnd = dictBase + dictLimit; - const BYTE* const prefixStart = base + dictLimit; - const U32 current = (U32)(ip-base); - const U32 btLow = btMask >= current ? 0 : current - btMask; - const U32 windowLow = zc->lowLimit; - U32* smallerPtr = bt + 2*(current&btMask); - U32* largerPtr = bt + 2*(current&btMask) + 1; - size_t bestLength = 0; - U32 matchEndIdx = current+8; - U32 dummy32; /* to be nullified at the end */ - - hashTable[h] = current; /* Update Hash Table */ - - while (nbCompares-- && (matchIndex > windowLow)) - { - U32* nextPtr = bt + 2*(matchIndex & btMask); - size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */ - const BYTE* match; - - if (matchIndex+matchLength >= dictLimit) - { - match = base + matchIndex; - if (match[matchLength] == ip[matchLength]) - matchLength += ZSTD_count(ip+matchLength+1, match+matchLength+1, iend) +1; - } - else - { - match = dictBase + matchIndex; - matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart); - if (matchIndex+matchLength >= dictLimit) - match = base + matchIndex; /* to prepare for next usage of match[matchLength] */ - } - - if (matchLength > bestLength) - { - if (matchLength > matchEndIdx - matchIndex) - matchEndIdx = matchIndex + (U32)matchLength; - if ( (4*(int)(matchLength-bestLength)) > (int)(ZSTD_highbit(current-matchIndex+1) - ZSTD_highbit((U32)offsetPtr[0]+1)) ) - bestLength = matchLength, *offsetPtr = current - matchIndex; - if (ip+matchLength == iend) /* equal : no way to know if inf or sup */ - break; /* drop, to guarantee consistency (miss a little bit of compression) */ - } - - if (match[matchLength] < ip[matchLength]) - { - /* match is smaller than current */ - *smallerPtr = matchIndex; /* update smaller idx */ - commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */ - if (matchIndex <= btLow) { smallerPtr=&dummy32; break; } /* beyond tree size, stop the search */ - smallerPtr = nextPtr+1; /* new "smaller" => larger of match */ - matchIndex = nextPtr[1]; /* new matchIndex larger than previous (closer to current) */ - } - else - { - /* match is larger than current */ - *largerPtr = matchIndex; - commonLengthLarger = matchLength; - if (matchIndex <= btLow) { largerPtr=&dummy32; break; } /* beyond tree size, stop the search */ - largerPtr = nextPtr; - matchIndex = nextPtr[0]; - } - } - - *smallerPtr = *largerPtr = 0; - - zc->nextToUpdate = (matchEndIdx > current + 8) ? matchEndIdx - 8 : current+1; - return bestLength; -} - /** Tree updater, providing best match */ FORCE_INLINE /* inlining is important to hardwire a hot branch (template emulation) */ size_t ZSTD_BtFindBestMatch_extDict ( @@ -1315,7 +1243,7 @@ size_t ZSTD_BtFindBestMatch_extDict ( { if (ip < zc->base + zc->nextToUpdate) return 0; /* skipped area */ ZSTD_updateTree_extDict(zc, ip, iLimit, maxNbAttempts, mls); - return ZSTD_insertBtAndFindBestMatch_extDict(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls); + return ZSTD_insertBtAndFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls, 1); }