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Make loadedDictEnd an Index, not the Dict Len

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This commit is contained in:
W. Felix Handte 2018-05-21 20:12:11 -04:00
parent 7ef85e0618
commit 298d24fa57
3 changed files with 10 additions and 2 deletions
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4
lib/compress/zstd_compress.c
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@ -1209,6 +1209,8 @@ static size_t ZSTD_resetCCtx_usingCDict(ZSTD_CCtx* cctx,
* in-place. We decide here which strategy to use. */
const int attachDict = ( pledgedSrcSize <= 8 KB
|| pledgedSrcSize == ZSTD_CONTENTSIZE_UNKNOWN )
&& !params.forceWindow /* dictMatchState isn't correctly
* handled in _enforceMaxDist */
&& cdict->cParams.strategy == ZSTD_fast
&& ZSTD_equivalentCParams(cctx->appliedParams.cParams,
cdict->cParams);
@ -1244,7 +1246,7 @@ static size_t ZSTD_resetCCtx_usingCDict(ZSTD_CCtx* cctx,
cctx->blockState.matchState.window.base + cdictLen;
ZSTD_window_clear(&cctx->blockState.matchState.window);
}
cctx->blockState.matchState.loadedDictEnd = params.forceWindow ? 0 : cdictLen;
cctx->blockState.matchState.loadedDictEnd = cctx->blockState.matchState.window.dictLimit;
}
} else {
DEBUGLOG(4, "copying dictionary into context");

6
lib/compress/zstd_compress_internal.h
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@ -594,14 +594,20 @@ MEM_STATIC U32 ZSTD_window_correctOverflow(ZSTD_window_t* window, U32 cycleLog,
* ZSTD_window_enforceMaxDist():
* Updates lowLimit so that:
* (srcEnd - base) - lowLimit == maxDist + loadedDictEnd
*
* This allows a simple check that index >= lowLimit to see if index is valid.
* This must be called before a block compression call, with srcEnd as the block
* source end.
*
* If loadedDictEndPtr is not NULL, we set it to zero once we update lowLimit.
* This is because dictionaries are allowed to be referenced as long as the last
* byte of the dictionary is in the window, but once they are out of range,
* they cannot be referenced. If loadedDictEndPtr is NULL, we use
* loadedDictEnd == 0.
*
* In normal dict mode, the dict is between lowLimit and dictLimit. In
* dictMatchState mode, lowLimit and dictLimit are the same, and the dictionary
* is below them. forceWindow and dictMatchState are therefore incompatible.
*/
MEM_STATIC void ZSTD_window_enforceMaxDist(ZSTD_window_t* window,
void const* srcEnd, U32 maxDist,

2
lib/compress/zstd_fast.c
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@ -72,7 +72,7 @@ size_t ZSTD_compressBlock_fast_generic(
const BYTE* const dictEnd = dictMode == ZSTD_dictMatchState ?
dms->window.nextSrc : NULL;
const U32 dictIndexDelta = dictMode == ZSTD_dictMatchState ?
prefixLowestIndex - (U32)(dictEnd - dictBase) :
ms->loadedDictEnd - (U32)(dictEnd - dictBase) :
0;
const U32 dictAndPrefixLength = (U32)(ip - prefixLowest + dictEnd - dictLowest);