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minor code cleaning for new index invalidation strategy

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This commit is contained in:
Yann Collet 2019-05-31 16:52:37 -07:00
parent d605f482c7
commit a968099038
2 changed files with 4 additions and 14 deletions
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2
lib/compress/zstd_compress.c
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@ -2868,8 +2868,8 @@ static size_t ZSTD_compress_frameChunk (ZSTD_CCtx* cctx,
ms->dictMatchState = NULL; ms->dictMatchState = NULL;
} }
//ZSTD_window_enforceMaxDist(&ms->window, ip + blockSize, maxDist, &ms->loadedDictEnd, &ms->dictMatchState);
ZSTD_checkDictValidity(&ms->window, ip + blockSize, maxDist, &ms->loadedDictEnd, &ms->dictMatchState); ZSTD_checkDictValidity(&ms->window, ip + blockSize, maxDist, &ms->loadedDictEnd, &ms->dictMatchState);
/* Ensure hash/chain table insertion resumes no sooner than lowlimit */ /* Ensure hash/chain table insertion resumes no sooner than lowlimit */
if (ms->nextToUpdate < ms->window.lowLimit) ms->nextToUpdate = ms->window.lowLimit; if (ms->nextToUpdate < ms->window.lowLimit) ms->nextToUpdate = ms->window.lowLimit;

16
lib/compress/zstd_compress_internal.h
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@ -731,6 +731,9 @@ ZSTD_window_enforceMaxDist(ZSTD_window_t* window,
} }
} }
/* Similar to ZSTD_window_enforceMaxDist(),
* but only invalidates dictionary
* when input progresses beyond window size. */
MEM_STATIC void MEM_STATIC void
ZSTD_checkDictValidity(ZSTD_window_t* window, ZSTD_checkDictValidity(ZSTD_window_t* window,
const void* blockEnd, const void* blockEnd,
@ -743,19 +746,6 @@ ZSTD_checkDictValidity(ZSTD_window_t* window,
DEBUGLOG(5, "ZSTD_checkDictValidity: blockEndIdx=%u, maxDist=%u, loadedDictEnd=%u", DEBUGLOG(5, "ZSTD_checkDictValidity: blockEndIdx=%u, maxDist=%u, loadedDictEnd=%u",
(unsigned)blockEndIdx, (unsigned)maxDist, (unsigned)loadedDictEnd); (unsigned)blockEndIdx, (unsigned)maxDist, (unsigned)loadedDictEnd);
/* - When there is no dictionary : loadedDictEnd == 0.
In which case, the test (blockEndIdx > maxDist) is merely to avoid
overflowing next operation `newLowLimit = blockEndIdx - maxDist`.
- When there is a standard dictionary :
Index referential is copied from the dictionary,
which means it starts from 0.
In which case, loadedDictEnd == dictSize,
and it makes sense to compare `blockEndIdx > maxDist + dictSize`
since `blockEndIdx` also starts from zero.
- When there is an attached dictionary :
loadedDictEnd is expressed within the referential of the context,
so it can be directly compared against blockEndIdx.
*/
if (loadedDictEnd && (blockEndIdx > maxDist + loadedDictEnd)) { if (loadedDictEnd && (blockEndIdx > maxDist + loadedDictEnd)) {
/* On reaching window size, dictionaries are invalidated */ /* On reaching window size, dictionaries are invalidated */
if (loadedDictEndPtr) *loadedDictEndPtr = 0; if (loadedDictEndPtr) *loadedDictEndPtr = 0;