diff options
Diffstat (limited to 'thirdparty/zstd/compress/zstd_compress_internal.h')
| -rw-r--r-- | thirdparty/zstd/compress/zstd_compress_internal.h | 104 |
1 files changed, 74 insertions, 30 deletions
diff --git a/thirdparty/zstd/compress/zstd_compress_internal.h b/thirdparty/zstd/compress/zstd_compress_internal.h index cc3cbb9da9..5495899be3 100644 --- a/thirdparty/zstd/compress/zstd_compress_internal.h +++ b/thirdparty/zstd/compress/zstd_compress_internal.h @@ -33,13 +33,13 @@ extern "C" { ***************************************/ #define kSearchStrength 8 #define HASH_READ_SIZE 8 -#define ZSTD_DUBT_UNSORTED_MARK 1 /* For btlazy2 strategy, index 1 now means "unsorted". +#define ZSTD_DUBT_UNSORTED_MARK 1 /* For btlazy2 strategy, index ZSTD_DUBT_UNSORTED_MARK==1 means "unsorted". It could be confused for a real successor at index "1", if sorted as larger than its predecessor. It's not a big deal though : candidate will just be sorted again. Additionally, candidate position 1 will be lost. But candidate 1 cannot hide a large tree of candidates, so it's a minimal loss. - The benefit is that ZSTD_DUBT_UNSORTED_MARK cannot be mishandled after table re-use with a different strategy - Constant required by ZSTD_compressBlock_btlazy2() and ZSTD_reduceTable_internal() */ + The benefit is that ZSTD_DUBT_UNSORTED_MARK cannot be mishandled after table re-use with a different strategy. + This constant is required by ZSTD_compressBlock_btlazy2() and ZSTD_reduceTable_internal() */ /*-************************************* @@ -128,21 +128,20 @@ typedef struct { BYTE const* base; /* All regular indexes relative to this position */ BYTE const* dictBase; /* extDict indexes relative to this position */ U32 dictLimit; /* below that point, need extDict */ - U32 lowLimit; /* below that point, no more data */ + U32 lowLimit; /* below that point, no more valid data */ } ZSTD_window_t; typedef struct ZSTD_matchState_t ZSTD_matchState_t; struct ZSTD_matchState_t { ZSTD_window_t window; /* State for window round buffer management */ - U32 loadedDictEnd; /* index of end of dictionary */ + U32 loadedDictEnd; /* index of end of dictionary, within context's referential. When dict referential is copied into active context (i.e. not attached), effectively same value as dictSize, since referential starts from zero */ U32 nextToUpdate; /* index from which to continue table update */ - U32 nextToUpdate3; /* index from which to continue table update */ U32 hashLog3; /* dispatch table : larger == faster, more memory */ U32* hashTable; U32* hashTable3; U32* chainTable; optState_t opt; /* optimal parser state */ - const ZSTD_matchState_t * dictMatchState; + const ZSTD_matchState_t* dictMatchState; ZSTD_compressionParameters cParams; }; @@ -195,6 +194,9 @@ struct ZSTD_CCtx_params_s { int compressionLevel; int forceWindow; /* force back-references to respect limit of * 1<<wLog, even for dictionary */ + size_t targetCBlockSize; /* Tries to fit compressed block size to be around targetCBlockSize. + * No target when targetCBlockSize == 0. + * There is no guarantee on compressed block size */ ZSTD_dictAttachPref_e attachDictPref; ZSTD_literalCompressionMode_e literalCompressionMode; @@ -324,7 +326,7 @@ MEM_STATIC void ZSTD_storeSeq(seqStore_t* seqStorePtr, size_t litLength, const v /* copy Literals */ assert(seqStorePtr->maxNbLit <= 128 KB); assert(seqStorePtr->lit + litLength <= seqStorePtr->litStart + seqStorePtr->maxNbLit); - ZSTD_wildcopy(seqStorePtr->lit, literals, litLength); + ZSTD_wildcopy(seqStorePtr->lit, literals, litLength, ZSTD_no_overlap); seqStorePtr->lit += litLength; /* literal Length */ @@ -564,6 +566,9 @@ MEM_STATIC U64 ZSTD_rollingHash_rotate(U64 hash, BYTE toRemove, BYTE toAdd, U64 /*-************************************* * Round buffer management ***************************************/ +#if (ZSTD_WINDOWLOG_MAX_64 > 31) +# error "ZSTD_WINDOWLOG_MAX is too large : would overflow ZSTD_CURRENT_MAX" +#endif /* Max current allowed */ #define ZSTD_CURRENT_MAX ((3U << 29) + (1U << ZSTD_WINDOWLOG_MAX)) /* Maximum chunk size before overflow correction needs to be called again */ @@ -675,31 +680,49 @@ MEM_STATIC U32 ZSTD_window_correctOverflow(ZSTD_window_t* window, U32 cycleLog, * 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. + * It ensures index is valid as long as index >= lowLimit. + * This must be called before a block compression call. + * + * loadedDictEnd is only defined if a dictionary is in use for current compression. + * As the name implies, loadedDictEnd represents the index at end of dictionary. + * The value lies within context's referential, it can be directly compared to blockEndIdx. * - * 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. + * If loadedDictEndPtr is NULL, no dictionary is in use, and we use loadedDictEnd == 0. + * If loadedDictEndPtr is not NULL, we set it to zero after updating lowLimit. + * This is because dictionaries are allowed to be referenced fully + * as long as the last byte of the dictionary is in the window. + * Once input has progressed beyond window size, dictionary cannot be referenced anymore. * - * 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. + * In normal dict mode, the dictionary lies 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, - U32* loadedDictEndPtr, + const void* blockEnd, + U32 maxDist, + U32* loadedDictEndPtr, const ZSTD_matchState_t** dictMatchStatePtr) { - U32 const blockEndIdx = (U32)((BYTE const*)srcEnd - window->base); - U32 loadedDictEnd = (loadedDictEndPtr != NULL) ? *loadedDictEndPtr : 0; - DEBUGLOG(5, "ZSTD_window_enforceMaxDist: blockEndIdx=%u, maxDist=%u", - (unsigned)blockEndIdx, (unsigned)maxDist); + U32 const blockEndIdx = (U32)((BYTE const*)blockEnd - window->base); + U32 const loadedDictEnd = (loadedDictEndPtr != NULL) ? *loadedDictEndPtr : 0; + DEBUGLOG(5, "ZSTD_window_enforceMaxDist: blockEndIdx=%u, maxDist=%u, loadedDictEnd=%u", + (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 (blockEndIdx > maxDist + loadedDictEnd) { U32 const newLowLimit = blockEndIdx - maxDist; if (window->lowLimit < newLowLimit) window->lowLimit = newLowLimit; @@ -708,10 +731,31 @@ ZSTD_window_enforceMaxDist(ZSTD_window_t* window, (unsigned)window->dictLimit, (unsigned)window->lowLimit); window->dictLimit = window->lowLimit; } - if (loadedDictEndPtr) - *loadedDictEndPtr = 0; - if (dictMatchStatePtr) - *dictMatchStatePtr = NULL; + /* On reaching window size, dictionaries are invalidated */ + if (loadedDictEndPtr) *loadedDictEndPtr = 0; + if (dictMatchStatePtr) *dictMatchStatePtr = NULL; + } +} + +/* Similar to ZSTD_window_enforceMaxDist(), + * but only invalidates dictionary + * when input progresses beyond window size. */ +MEM_STATIC void +ZSTD_checkDictValidity(ZSTD_window_t* window, + const void* blockEnd, + U32 maxDist, + U32* loadedDictEndPtr, + const ZSTD_matchState_t** dictMatchStatePtr) +{ + U32 const blockEndIdx = (U32)((BYTE const*)blockEnd - window->base); + U32 const loadedDictEnd = (loadedDictEndPtr != NULL) ? *loadedDictEndPtr : 0; + DEBUGLOG(5, "ZSTD_checkDictValidity: blockEndIdx=%u, maxDist=%u, loadedDictEnd=%u", + (unsigned)blockEndIdx, (unsigned)maxDist, (unsigned)loadedDictEnd); + + if (loadedDictEnd && (blockEndIdx > maxDist + loadedDictEnd)) { + /* On reaching window size, dictionaries are invalidated */ + if (loadedDictEndPtr) *loadedDictEndPtr = 0; + if (dictMatchStatePtr) *dictMatchStatePtr = NULL; } } |