diff options
Diffstat (limited to 'thirdparty/zstd/compress/huf_compress.c')
-rw-r--r-- | thirdparty/zstd/compress/huf_compress.c | 641 |
1 files changed, 537 insertions, 104 deletions
diff --git a/thirdparty/zstd/compress/huf_compress.c b/thirdparty/zstd/compress/huf_compress.c index 485906e678..2b3d6adc2a 100644 --- a/thirdparty/zstd/compress/huf_compress.c +++ b/thirdparty/zstd/compress/huf_compress.c @@ -53,6 +53,28 @@ unsigned HUF_optimalTableLog(unsigned maxTableLog, size_t srcSize, unsigned maxS /* ******************************************************* * HUF : Huffman block compression *********************************************************/ +#define HUF_WORKSPACE_MAX_ALIGNMENT 8 + +static void* HUF_alignUpWorkspace(void* workspace, size_t* workspaceSizePtr, size_t align) +{ + size_t const mask = align - 1; + size_t const rem = (size_t)workspace & mask; + size_t const add = (align - rem) & mask; + BYTE* const aligned = (BYTE*)workspace + add; + assert((align & (align - 1)) == 0); /* pow 2 */ + assert(align <= HUF_WORKSPACE_MAX_ALIGNMENT); + if (*workspaceSizePtr >= add) { + assert(add < align); + assert(((size_t)aligned & mask) == 0); + *workspaceSizePtr -= add; + return aligned; + } else { + *workspaceSizePtr = 0; + return NULL; + } +} + + /* HUF_compressWeights() : * Same as FSE_compress(), but dedicated to huff0's weights compression. * The use case needs much less stack memory. @@ -75,7 +97,7 @@ static size_t HUF_compressWeights(void* dst, size_t dstSize, const void* weightT unsigned maxSymbolValue = HUF_TABLELOG_MAX; U32 tableLog = MAX_FSE_TABLELOG_FOR_HUFF_HEADER; - HUF_CompressWeightsWksp* wksp = (HUF_CompressWeightsWksp*)workspace; + HUF_CompressWeightsWksp* wksp = (HUF_CompressWeightsWksp*)HUF_alignUpWorkspace(workspace, &workspaceSize, ZSTD_ALIGNOF(U32)); if (workspaceSize < sizeof(HUF_CompressWeightsWksp)) return ERROR(GENERIC); @@ -106,6 +128,40 @@ static size_t HUF_compressWeights(void* dst, size_t dstSize, const void* weightT return (size_t)(op-ostart); } +static size_t HUF_getNbBits(HUF_CElt elt) +{ + return elt & 0xFF; +} + +static size_t HUF_getNbBitsFast(HUF_CElt elt) +{ + return elt; +} + +static size_t HUF_getValue(HUF_CElt elt) +{ + return elt & ~0xFF; +} + +static size_t HUF_getValueFast(HUF_CElt elt) +{ + return elt; +} + +static void HUF_setNbBits(HUF_CElt* elt, size_t nbBits) +{ + assert(nbBits <= HUF_TABLELOG_ABSOLUTEMAX); + *elt = nbBits; +} + +static void HUF_setValue(HUF_CElt* elt, size_t value) +{ + size_t const nbBits = HUF_getNbBits(*elt); + if (nbBits > 0) { + assert((value >> nbBits) == 0); + *elt |= value << (sizeof(HUF_CElt) * 8 - nbBits); + } +} typedef struct { HUF_CompressWeightsWksp wksp; @@ -117,9 +173,10 @@ size_t HUF_writeCTable_wksp(void* dst, size_t maxDstSize, const HUF_CElt* CTable, unsigned maxSymbolValue, unsigned huffLog, void* workspace, size_t workspaceSize) { + HUF_CElt const* const ct = CTable + 1; BYTE* op = (BYTE*)dst; U32 n; - HUF_WriteCTableWksp* wksp = (HUF_WriteCTableWksp*)workspace; + HUF_WriteCTableWksp* wksp = (HUF_WriteCTableWksp*)HUF_alignUpWorkspace(workspace, &workspaceSize, ZSTD_ALIGNOF(U32)); /* check conditions */ if (workspaceSize < sizeof(HUF_WriteCTableWksp)) return ERROR(GENERIC); @@ -130,9 +187,10 @@ size_t HUF_writeCTable_wksp(void* dst, size_t maxDstSize, for (n=1; n<huffLog+1; n++) wksp->bitsToWeight[n] = (BYTE)(huffLog + 1 - n); for (n=0; n<maxSymbolValue; n++) - wksp->huffWeight[n] = wksp->bitsToWeight[CTable[n].nbBits]; + wksp->huffWeight[n] = wksp->bitsToWeight[HUF_getNbBits(ct[n])]; /* attempt weights compression by FSE */ + if (maxDstSize < 1) return ERROR(dstSize_tooSmall); { CHECK_V_F(hSize, HUF_compressWeights(op+1, maxDstSize-1, wksp->huffWeight, maxSymbolValue, &wksp->wksp, sizeof(wksp->wksp)) ); if ((hSize>1) & (hSize < maxSymbolValue/2)) { /* FSE compressed */ op[0] = (BYTE)hSize; @@ -166,6 +224,7 @@ size_t HUF_readCTable (HUF_CElt* CTable, unsigned* maxSymbolValuePtr, const void U32 rankVal[HUF_TABLELOG_ABSOLUTEMAX + 1]; /* large enough for values from 0 to 16 */ U32 tableLog = 0; U32 nbSymbols = 0; + HUF_CElt* const ct = CTable + 1; /* get symbol weights */ CHECK_V_F(readSize, HUF_readStats(huffWeight, HUF_SYMBOLVALUE_MAX+1, rankVal, &nbSymbols, &tableLog, src, srcSize)); @@ -175,6 +234,8 @@ size_t HUF_readCTable (HUF_CElt* CTable, unsigned* maxSymbolValuePtr, const void if (tableLog > HUF_TABLELOG_MAX) return ERROR(tableLog_tooLarge); if (nbSymbols > *maxSymbolValuePtr+1) return ERROR(maxSymbolValue_tooSmall); + CTable[0] = tableLog; + /* Prepare base value per rank */ { U32 n, nextRankStart = 0; for (n=1; n<=tableLog; n++) { @@ -186,13 +247,13 @@ size_t HUF_readCTable (HUF_CElt* CTable, unsigned* maxSymbolValuePtr, const void /* fill nbBits */ { U32 n; for (n=0; n<nbSymbols; n++) { const U32 w = huffWeight[n]; - CTable[n].nbBits = (BYTE)(tableLog + 1 - w) & -(w != 0); + HUF_setNbBits(ct + n, (BYTE)(tableLog + 1 - w) & -(w != 0)); } } /* fill val */ { U16 nbPerRank[HUF_TABLELOG_MAX+2] = {0}; /* support w=0=>n=tableLog+1 */ U16 valPerRank[HUF_TABLELOG_MAX+2] = {0}; - { U32 n; for (n=0; n<nbSymbols; n++) nbPerRank[CTable[n].nbBits]++; } + { U32 n; for (n=0; n<nbSymbols; n++) nbPerRank[HUF_getNbBits(ct[n])]++; } /* determine stating value per rank */ valPerRank[tableLog+1] = 0; /* for w==0 */ { U16 min = 0; @@ -202,18 +263,18 @@ size_t HUF_readCTable (HUF_CElt* CTable, unsigned* maxSymbolValuePtr, const void min >>= 1; } } /* assign value within rank, symbol order */ - { U32 n; for (n=0; n<nbSymbols; n++) CTable[n].val = valPerRank[CTable[n].nbBits]++; } + { U32 n; for (n=0; n<nbSymbols; n++) HUF_setValue(ct + n, valPerRank[HUF_getNbBits(ct[n])]++); } } *maxSymbolValuePtr = nbSymbols - 1; return readSize; } -U32 HUF_getNbBits(const void* symbolTable, U32 symbolValue) +U32 HUF_getNbBitsFromCTable(HUF_CElt const* CTable, U32 symbolValue) { - const HUF_CElt* table = (const HUF_CElt*)symbolTable; + const HUF_CElt* ct = CTable + 1; assert(symbolValue <= HUF_SYMBOLVALUE_MAX); - return table[symbolValue].nbBits; + return (U32)HUF_getNbBits(ct[symbolValue]); } @@ -367,22 +428,118 @@ static U32 HUF_setMaxHeight(nodeElt* huffNode, U32 lastNonNull, U32 maxNbBits) } typedef struct { - U32 base; - U32 curr; + U16 base; + U16 curr; } rankPos; typedef nodeElt huffNodeTable[HUF_CTABLE_WORKSPACE_SIZE_U32]; -#define RANK_POSITION_TABLE_SIZE 32 +/* Number of buckets available for HUF_sort() */ +#define RANK_POSITION_TABLE_SIZE 192 typedef struct { huffNodeTable huffNodeTbl; rankPos rankPosition[RANK_POSITION_TABLE_SIZE]; } HUF_buildCTable_wksp_tables; +/* RANK_POSITION_DISTINCT_COUNT_CUTOFF == Cutoff point in HUF_sort() buckets for which we use log2 bucketing. + * Strategy is to use as many buckets as possible for representing distinct + * counts while using the remainder to represent all "large" counts. + * + * To satisfy this requirement for 192 buckets, we can do the following: + * Let buckets 0-166 represent distinct counts of [0, 166] + * Let buckets 166 to 192 represent all remaining counts up to RANK_POSITION_MAX_COUNT_LOG using log2 bucketing. + */ +#define RANK_POSITION_MAX_COUNT_LOG 32 +#define RANK_POSITION_LOG_BUCKETS_BEGIN (RANK_POSITION_TABLE_SIZE - 1) - RANK_POSITION_MAX_COUNT_LOG - 1 /* == 158 */ +#define RANK_POSITION_DISTINCT_COUNT_CUTOFF RANK_POSITION_LOG_BUCKETS_BEGIN + BIT_highbit32(RANK_POSITION_LOG_BUCKETS_BEGIN) /* == 166 */ + +/* Return the appropriate bucket index for a given count. See definition of + * RANK_POSITION_DISTINCT_COUNT_CUTOFF for explanation of bucketing strategy. + */ +static U32 HUF_getIndex(U32 const count) { + return (count < RANK_POSITION_DISTINCT_COUNT_CUTOFF) + ? count + : BIT_highbit32(count) + RANK_POSITION_LOG_BUCKETS_BEGIN; +} + +/* Helper swap function for HUF_quickSortPartition() */ +static void HUF_swapNodes(nodeElt* a, nodeElt* b) { + nodeElt tmp = *a; + *a = *b; + *b = tmp; +} + +/* Returns 0 if the huffNode array is not sorted by descending count */ +MEM_STATIC int HUF_isSorted(nodeElt huffNode[], U32 const maxSymbolValue1) { + U32 i; + for (i = 1; i < maxSymbolValue1; ++i) { + if (huffNode[i].count > huffNode[i-1].count) { + return 0; + } + } + return 1; +} + +/* Insertion sort by descending order */ +HINT_INLINE void HUF_insertionSort(nodeElt huffNode[], int const low, int const high) { + int i; + int const size = high-low+1; + huffNode += low; + for (i = 1; i < size; ++i) { + nodeElt const key = huffNode[i]; + int j = i - 1; + while (j >= 0 && huffNode[j].count < key.count) { + huffNode[j + 1] = huffNode[j]; + j--; + } + huffNode[j + 1] = key; + } +} + +/* Pivot helper function for quicksort. */ +static int HUF_quickSortPartition(nodeElt arr[], int const low, int const high) { + /* Simply select rightmost element as pivot. "Better" selectors like + * median-of-three don't experimentally appear to have any benefit. + */ + U32 const pivot = arr[high].count; + int i = low - 1; + int j = low; + for ( ; j < high; j++) { + if (arr[j].count > pivot) { + i++; + HUF_swapNodes(&arr[i], &arr[j]); + } + } + HUF_swapNodes(&arr[i + 1], &arr[high]); + return i + 1; +} + +/* Classic quicksort by descending with partially iterative calls + * to reduce worst case callstack size. + */ +static void HUF_simpleQuickSort(nodeElt arr[], int low, int high) { + int const kInsertionSortThreshold = 8; + if (high - low < kInsertionSortThreshold) { + HUF_insertionSort(arr, low, high); + return; + } + while (low < high) { + int const idx = HUF_quickSortPartition(arr, low, high); + if (idx - low < high - idx) { + HUF_simpleQuickSort(arr, low, idx - 1); + low = idx + 1; + } else { + HUF_simpleQuickSort(arr, idx + 1, high); + high = idx - 1; + } + } +} + /** * HUF_sort(): * Sorts the symbols [0, maxSymbolValue] by count[symbol] in decreasing order. + * This is a typical bucket sorting strategy that uses either quicksort or insertion sort to sort each bucket. * * @param[out] huffNode Sorted symbols by decreasing count. Only members `.count` and `.byte` are filled. * Must have (maxSymbolValue + 1) entries. @@ -390,44 +547,52 @@ typedef struct { * @param[in] maxSymbolValue Maximum symbol value. * @param rankPosition This is a scratch workspace. Must have RANK_POSITION_TABLE_SIZE entries. */ -static void HUF_sort(nodeElt* huffNode, const unsigned* count, U32 maxSymbolValue, rankPos* rankPosition) -{ - int n; - int const maxSymbolValue1 = (int)maxSymbolValue + 1; +static void HUF_sort(nodeElt huffNode[], const unsigned count[], U32 const maxSymbolValue, rankPos rankPosition[]) { + U32 n; + U32 const maxSymbolValue1 = maxSymbolValue+1; /* Compute base and set curr to base. - * For symbol s let lowerRank = BIT_highbit32(count[n]+1) and rank = lowerRank + 1. - * Then 2^lowerRank <= count[n]+1 <= 2^rank. + * For symbol s let lowerRank = HUF_getIndex(count[n]) and rank = lowerRank + 1. + * See HUF_getIndex to see bucketing strategy. * We attribute each symbol to lowerRank's base value, because we want to know where * each rank begins in the output, so for rank R we want to count ranks R+1 and above. */ ZSTD_memset(rankPosition, 0, sizeof(*rankPosition) * RANK_POSITION_TABLE_SIZE); for (n = 0; n < maxSymbolValue1; ++n) { - U32 lowerRank = BIT_highbit32(count[n] + 1); + U32 lowerRank = HUF_getIndex(count[n]); + assert(lowerRank < RANK_POSITION_TABLE_SIZE - 1); rankPosition[lowerRank].base++; } + assert(rankPosition[RANK_POSITION_TABLE_SIZE - 1].base == 0); + /* Set up the rankPosition table */ for (n = RANK_POSITION_TABLE_SIZE - 1; n > 0; --n) { rankPosition[n-1].base += rankPosition[n].base; rankPosition[n-1].curr = rankPosition[n-1].base; } - /* Sort */ + + /* Insert each symbol into their appropriate bucket, setting up rankPosition table. */ for (n = 0; n < maxSymbolValue1; ++n) { U32 const c = count[n]; - U32 const r = BIT_highbit32(c+1) + 1; - U32 pos = rankPosition[r].curr++; - /* Insert into the correct position in the rank. - * We have at most 256 symbols, so this insertion should be fine. - */ - while ((pos > rankPosition[r].base) && (c > huffNode[pos-1].count)) { - huffNode[pos] = huffNode[pos-1]; - pos--; - } + U32 const r = HUF_getIndex(c) + 1; + U32 const pos = rankPosition[r].curr++; + assert(pos < maxSymbolValue1); huffNode[pos].count = c; huffNode[pos].byte = (BYTE)n; } -} + /* Sort each bucket. */ + for (n = RANK_POSITION_DISTINCT_COUNT_CUTOFF; n < RANK_POSITION_TABLE_SIZE - 1; ++n) { + U32 const bucketSize = rankPosition[n].curr-rankPosition[n].base; + U32 const bucketStartIdx = rankPosition[n].base; + if (bucketSize > 1) { + assert(bucketStartIdx < maxSymbolValue1); + HUF_simpleQuickSort(huffNode + bucketStartIdx, 0, bucketSize-1); + } + } + + assert(HUF_isSorted(huffNode, maxSymbolValue1)); +} /** HUF_buildCTable_wksp() : * Same as HUF_buildCTable(), but using externally allocated scratch buffer. @@ -490,6 +655,7 @@ static int HUF_buildTree(nodeElt* huffNode, U32 maxSymbolValue) */ static void HUF_buildCTableFromTree(HUF_CElt* CTable, nodeElt const* huffNode, int nonNullRank, U32 maxSymbolValue, U32 maxNbBits) { + HUF_CElt* const ct = CTable + 1; /* fill result into ctable (val, nbBits) */ int n; U16 nbPerRank[HUF_TABLELOG_MAX+1] = {0}; @@ -505,20 +671,20 @@ static void HUF_buildCTableFromTree(HUF_CElt* CTable, nodeElt const* huffNode, i min >>= 1; } } for (n=0; n<alphabetSize; n++) - CTable[huffNode[n].byte].nbBits = huffNode[n].nbBits; /* push nbBits per symbol, symbol order */ + HUF_setNbBits(ct + huffNode[n].byte, huffNode[n].nbBits); /* push nbBits per symbol, symbol order */ for (n=0; n<alphabetSize; n++) - CTable[n].val = valPerRank[CTable[n].nbBits]++; /* assign value within rank, symbol order */ + HUF_setValue(ct + n, valPerRank[HUF_getNbBits(ct[n])]++); /* assign value within rank, symbol order */ + CTable[0] = maxNbBits; } -size_t HUF_buildCTable_wksp (HUF_CElt* tree, const unsigned* count, U32 maxSymbolValue, U32 maxNbBits, void* workSpace, size_t wkspSize) +size_t HUF_buildCTable_wksp (HUF_CElt* CTable, const unsigned* count, U32 maxSymbolValue, U32 maxNbBits, void* workSpace, size_t wkspSize) { - HUF_buildCTable_wksp_tables* const wksp_tables = (HUF_buildCTable_wksp_tables*)workSpace; + HUF_buildCTable_wksp_tables* const wksp_tables = (HUF_buildCTable_wksp_tables*)HUF_alignUpWorkspace(workSpace, &wkspSize, ZSTD_ALIGNOF(U32)); nodeElt* const huffNode0 = wksp_tables->huffNodeTbl; nodeElt* const huffNode = huffNode0+1; int nonNullRank; /* safety checks */ - if (((size_t)workSpace & 3) != 0) return ERROR(GENERIC); /* must be aligned on 4-bytes boundaries */ if (wkspSize < sizeof(HUF_buildCTable_wksp_tables)) return ERROR(workSpace_tooSmall); if (maxNbBits == 0) maxNbBits = HUF_TABLELOG_DEFAULT; @@ -536,96 +702,334 @@ size_t HUF_buildCTable_wksp (HUF_CElt* tree, const unsigned* count, U32 maxSymbo maxNbBits = HUF_setMaxHeight(huffNode, (U32)nonNullRank, maxNbBits); if (maxNbBits > HUF_TABLELOG_MAX) return ERROR(GENERIC); /* check fit into table */ - HUF_buildCTableFromTree(tree, huffNode, nonNullRank, maxSymbolValue, maxNbBits); + HUF_buildCTableFromTree(CTable, huffNode, nonNullRank, maxSymbolValue, maxNbBits); return maxNbBits; } size_t HUF_estimateCompressedSize(const HUF_CElt* CTable, const unsigned* count, unsigned maxSymbolValue) { + HUF_CElt const* ct = CTable + 1; size_t nbBits = 0; int s; for (s = 0; s <= (int)maxSymbolValue; ++s) { - nbBits += CTable[s].nbBits * count[s]; + nbBits += HUF_getNbBits(ct[s]) * count[s]; } return nbBits >> 3; } int HUF_validateCTable(const HUF_CElt* CTable, const unsigned* count, unsigned maxSymbolValue) { + HUF_CElt const* ct = CTable + 1; int bad = 0; int s; for (s = 0; s <= (int)maxSymbolValue; ++s) { - bad |= (count[s] != 0) & (CTable[s].nbBits == 0); + bad |= (count[s] != 0) & (HUF_getNbBits(ct[s]) == 0); } return !bad; } size_t HUF_compressBound(size_t size) { return HUF_COMPRESSBOUND(size); } +/** HUF_CStream_t: + * Huffman uses its own BIT_CStream_t implementation. + * There are three major differences from BIT_CStream_t: + * 1. HUF_addBits() takes a HUF_CElt (size_t) which is + * the pair (nbBits, value) in the format: + * format: + * - Bits [0, 4) = nbBits + * - Bits [4, 64 - nbBits) = 0 + * - Bits [64 - nbBits, 64) = value + * 2. The bitContainer is built from the upper bits and + * right shifted. E.g. to add a new value of N bits + * you right shift the bitContainer by N, then or in + * the new value into the N upper bits. + * 3. The bitstream has two bit containers. You can add + * bits to the second container and merge them into + * the first container. + */ + +#define HUF_BITS_IN_CONTAINER (sizeof(size_t) * 8) + +typedef struct { + size_t bitContainer[2]; + size_t bitPos[2]; + + BYTE* startPtr; + BYTE* ptr; + BYTE* endPtr; +} HUF_CStream_t; + +/**! HUF_initCStream(): + * Initializes the bitstream. + * @returns 0 or an error code. + */ +static size_t HUF_initCStream(HUF_CStream_t* bitC, + void* startPtr, size_t dstCapacity) +{ + ZSTD_memset(bitC, 0, sizeof(*bitC)); + bitC->startPtr = (BYTE*)startPtr; + bitC->ptr = bitC->startPtr; + bitC->endPtr = bitC->startPtr + dstCapacity - sizeof(bitC->bitContainer[0]); + if (dstCapacity <= sizeof(bitC->bitContainer[0])) return ERROR(dstSize_tooSmall); + return 0; +} + +/*! HUF_addBits(): + * Adds the symbol stored in HUF_CElt elt to the bitstream. + * + * @param elt The element we're adding. This is a (nbBits, value) pair. + * See the HUF_CStream_t docs for the format. + * @param idx Insert into the bitstream at this idx. + * @param kFast This is a template parameter. If the bitstream is guaranteed + * to have at least 4 unused bits after this call it may be 1, + * otherwise it must be 0. HUF_addBits() is faster when fast is set. + */ +FORCE_INLINE_TEMPLATE void HUF_addBits(HUF_CStream_t* bitC, HUF_CElt elt, int idx, int kFast) +{ + assert(idx <= 1); + assert(HUF_getNbBits(elt) <= HUF_TABLELOG_ABSOLUTEMAX); + /* This is efficient on x86-64 with BMI2 because shrx + * only reads the low 6 bits of the register. The compiler + * knows this and elides the mask. When fast is set, + * every operation can use the same value loaded from elt. + */ + bitC->bitContainer[idx] >>= HUF_getNbBits(elt); + bitC->bitContainer[idx] |= kFast ? HUF_getValueFast(elt) : HUF_getValue(elt); + /* We only read the low 8 bits of bitC->bitPos[idx] so it + * doesn't matter that the high bits have noise from the value. + */ + bitC->bitPos[idx] += HUF_getNbBitsFast(elt); + assert((bitC->bitPos[idx] & 0xFF) <= HUF_BITS_IN_CONTAINER); + /* The last 4-bits of elt are dirty if fast is set, + * so we must not be overwriting bits that have already been + * inserted into the bit container. + */ +#if DEBUGLEVEL >= 1 + { + size_t const nbBits = HUF_getNbBits(elt); + size_t const dirtyBits = nbBits == 0 ? 0 : BIT_highbit32((U32)nbBits) + 1; + (void)dirtyBits; + /* Middle bits are 0. */ + assert(((elt >> dirtyBits) << (dirtyBits + nbBits)) == 0); + /* We didn't overwrite any bits in the bit container. */ + assert(!kFast || (bitC->bitPos[idx] & 0xFF) <= HUF_BITS_IN_CONTAINER); + (void)dirtyBits; + } +#endif +} + +FORCE_INLINE_TEMPLATE void HUF_zeroIndex1(HUF_CStream_t* bitC) +{ + bitC->bitContainer[1] = 0; + bitC->bitPos[1] = 0; +} + +/*! HUF_mergeIndex1() : + * Merges the bit container @ index 1 into the bit container @ index 0 + * and zeros the bit container @ index 1. + */ +FORCE_INLINE_TEMPLATE void HUF_mergeIndex1(HUF_CStream_t* bitC) +{ + assert((bitC->bitPos[1] & 0xFF) < HUF_BITS_IN_CONTAINER); + bitC->bitContainer[0] >>= (bitC->bitPos[1] & 0xFF); + bitC->bitContainer[0] |= bitC->bitContainer[1]; + bitC->bitPos[0] += bitC->bitPos[1]; + assert((bitC->bitPos[0] & 0xFF) <= HUF_BITS_IN_CONTAINER); +} + +/*! HUF_flushBits() : +* Flushes the bits in the bit container @ index 0. +* +* @post bitPos will be < 8. +* @param kFast If kFast is set then we must know a-priori that +* the bit container will not overflow. +*/ +FORCE_INLINE_TEMPLATE void HUF_flushBits(HUF_CStream_t* bitC, int kFast) +{ + /* The upper bits of bitPos are noisy, so we must mask by 0xFF. */ + size_t const nbBits = bitC->bitPos[0] & 0xFF; + size_t const nbBytes = nbBits >> 3; + /* The top nbBits bits of bitContainer are the ones we need. */ + size_t const bitContainer = bitC->bitContainer[0] >> (HUF_BITS_IN_CONTAINER - nbBits); + /* Mask bitPos to account for the bytes we consumed. */ + bitC->bitPos[0] &= 7; + assert(nbBits > 0); + assert(nbBits <= sizeof(bitC->bitContainer[0]) * 8); + assert(bitC->ptr <= bitC->endPtr); + MEM_writeLEST(bitC->ptr, bitContainer); + bitC->ptr += nbBytes; + assert(!kFast || bitC->ptr <= bitC->endPtr); + if (!kFast && bitC->ptr > bitC->endPtr) bitC->ptr = bitC->endPtr; + /* bitContainer doesn't need to be modified because the leftover + * bits are already the top bitPos bits. And we don't care about + * noise in the lower values. + */ +} + +/*! HUF_endMark() + * @returns The Huffman stream end mark: A 1-bit value = 1. + */ +static HUF_CElt HUF_endMark(void) +{ + HUF_CElt endMark; + HUF_setNbBits(&endMark, 1); + HUF_setValue(&endMark, 1); + return endMark; +} + +/*! HUF_closeCStream() : + * @return Size of CStream, in bytes, + * or 0 if it could not fit into dstBuffer */ +static size_t HUF_closeCStream(HUF_CStream_t* bitC) +{ + HUF_addBits(bitC, HUF_endMark(), /* idx */ 0, /* kFast */ 0); + HUF_flushBits(bitC, /* kFast */ 0); + { + size_t const nbBits = bitC->bitPos[0] & 0xFF; + if (bitC->ptr >= bitC->endPtr) return 0; /* overflow detected */ + return (bitC->ptr - bitC->startPtr) + (nbBits > 0); + } +} + FORCE_INLINE_TEMPLATE void -HUF_encodeSymbol(BIT_CStream_t* bitCPtr, U32 symbol, const HUF_CElt* CTable) +HUF_encodeSymbol(HUF_CStream_t* bitCPtr, U32 symbol, const HUF_CElt* CTable, int idx, int fast) { - BIT_addBitsFast(bitCPtr, CTable[symbol].val, CTable[symbol].nbBits); + HUF_addBits(bitCPtr, CTable[symbol], idx, fast); } -#define HUF_FLUSHBITS(s) BIT_flushBits(s) +FORCE_INLINE_TEMPLATE void +HUF_compress1X_usingCTable_internal_body_loop(HUF_CStream_t* bitC, + const BYTE* ip, size_t srcSize, + const HUF_CElt* ct, + int kUnroll, int kFastFlush, int kLastFast) +{ + /* Join to kUnroll */ + int n = (int)srcSize; + int rem = n % kUnroll; + if (rem > 0) { + for (; rem > 0; --rem) { + HUF_encodeSymbol(bitC, ip[--n], ct, 0, /* fast */ 0); + } + HUF_flushBits(bitC, kFastFlush); + } + assert(n % kUnroll == 0); + + /* Join to 2 * kUnroll */ + if (n % (2 * kUnroll)) { + int u; + for (u = 1; u < kUnroll; ++u) { + HUF_encodeSymbol(bitC, ip[n - u], ct, 0, 1); + } + HUF_encodeSymbol(bitC, ip[n - kUnroll], ct, 0, kLastFast); + HUF_flushBits(bitC, kFastFlush); + n -= kUnroll; + } + assert(n % (2 * kUnroll) == 0); + + for (; n>0; n-= 2 * kUnroll) { + /* Encode kUnroll symbols into the bitstream @ index 0. */ + int u; + for (u = 1; u < kUnroll; ++u) { + HUF_encodeSymbol(bitC, ip[n - u], ct, /* idx */ 0, /* fast */ 1); + } + HUF_encodeSymbol(bitC, ip[n - kUnroll], ct, /* idx */ 0, /* fast */ kLastFast); + HUF_flushBits(bitC, kFastFlush); + /* Encode kUnroll symbols into the bitstream @ index 1. + * This allows us to start filling the bit container + * without any data dependencies. + */ + HUF_zeroIndex1(bitC); + for (u = 1; u < kUnroll; ++u) { + HUF_encodeSymbol(bitC, ip[n - kUnroll - u], ct, /* idx */ 1, /* fast */ 1); + } + HUF_encodeSymbol(bitC, ip[n - kUnroll - kUnroll], ct, /* idx */ 1, /* fast */ kLastFast); + /* Merge bitstream @ index 1 into the bitstream @ index 0 */ + HUF_mergeIndex1(bitC); + HUF_flushBits(bitC, kFastFlush); + } + assert(n == 0); + +} -#define HUF_FLUSHBITS_1(stream) \ - if (sizeof((stream)->bitContainer)*8 < HUF_TABLELOG_MAX*2+7) HUF_FLUSHBITS(stream) +/** + * Returns a tight upper bound on the output space needed by Huffman + * with 8 bytes buffer to handle over-writes. If the output is at least + * this large we don't need to do bounds checks during Huffman encoding. + */ +static size_t HUF_tightCompressBound(size_t srcSize, size_t tableLog) +{ + return ((srcSize * tableLog) >> 3) + 8; +} -#define HUF_FLUSHBITS_2(stream) \ - if (sizeof((stream)->bitContainer)*8 < HUF_TABLELOG_MAX*4+7) HUF_FLUSHBITS(stream) FORCE_INLINE_TEMPLATE size_t HUF_compress1X_usingCTable_internal_body(void* dst, size_t dstSize, const void* src, size_t srcSize, const HUF_CElt* CTable) { + U32 const tableLog = (U32)CTable[0]; + HUF_CElt const* ct = CTable + 1; const BYTE* ip = (const BYTE*) src; BYTE* const ostart = (BYTE*)dst; BYTE* const oend = ostart + dstSize; BYTE* op = ostart; - size_t n; - BIT_CStream_t bitC; + HUF_CStream_t bitC; /* init */ if (dstSize < 8) return 0; /* not enough space to compress */ - { size_t const initErr = BIT_initCStream(&bitC, op, (size_t)(oend-op)); + { size_t const initErr = HUF_initCStream(&bitC, op, (size_t)(oend-op)); if (HUF_isError(initErr)) return 0; } - n = srcSize & ~3; /* join to mod 4 */ - switch (srcSize & 3) - { - case 3 : HUF_encodeSymbol(&bitC, ip[n+ 2], CTable); - HUF_FLUSHBITS_2(&bitC); - /* fall-through */ - case 2 : HUF_encodeSymbol(&bitC, ip[n+ 1], CTable); - HUF_FLUSHBITS_1(&bitC); - /* fall-through */ - case 1 : HUF_encodeSymbol(&bitC, ip[n+ 0], CTable); - HUF_FLUSHBITS(&bitC); - /* fall-through */ - case 0 : /* fall-through */ - default: break; - } - - for (; n>0; n-=4) { /* note : n&3==0 at this stage */ - HUF_encodeSymbol(&bitC, ip[n- 1], CTable); - HUF_FLUSHBITS_1(&bitC); - HUF_encodeSymbol(&bitC, ip[n- 2], CTable); - HUF_FLUSHBITS_2(&bitC); - HUF_encodeSymbol(&bitC, ip[n- 3], CTable); - HUF_FLUSHBITS_1(&bitC); - HUF_encodeSymbol(&bitC, ip[n- 4], CTable); - HUF_FLUSHBITS(&bitC); + if (dstSize < HUF_tightCompressBound(srcSize, (size_t)tableLog) || tableLog > 11) + HUF_compress1X_usingCTable_internal_body_loop(&bitC, ip, srcSize, ct, /* kUnroll */ MEM_32bits() ? 2 : 4, /* kFast */ 0, /* kLastFast */ 0); + else { + if (MEM_32bits()) { + switch (tableLog) { + case 11: + HUF_compress1X_usingCTable_internal_body_loop(&bitC, ip, srcSize, ct, /* kUnroll */ 2, /* kFastFlush */ 1, /* kLastFast */ 0); + break; + case 10: ZSTD_FALLTHROUGH; + case 9: ZSTD_FALLTHROUGH; + case 8: + HUF_compress1X_usingCTable_internal_body_loop(&bitC, ip, srcSize, ct, /* kUnroll */ 2, /* kFastFlush */ 1, /* kLastFast */ 1); + break; + case 7: ZSTD_FALLTHROUGH; + default: + HUF_compress1X_usingCTable_internal_body_loop(&bitC, ip, srcSize, ct, /* kUnroll */ 3, /* kFastFlush */ 1, /* kLastFast */ 1); + break; + } + } else { + switch (tableLog) { + case 11: + HUF_compress1X_usingCTable_internal_body_loop(&bitC, ip, srcSize, ct, /* kUnroll */ 5, /* kFastFlush */ 1, /* kLastFast */ 0); + break; + case 10: + HUF_compress1X_usingCTable_internal_body_loop(&bitC, ip, srcSize, ct, /* kUnroll */ 5, /* kFastFlush */ 1, /* kLastFast */ 1); + break; + case 9: + HUF_compress1X_usingCTable_internal_body_loop(&bitC, ip, srcSize, ct, /* kUnroll */ 6, /* kFastFlush */ 1, /* kLastFast */ 0); + break; + case 8: + HUF_compress1X_usingCTable_internal_body_loop(&bitC, ip, srcSize, ct, /* kUnroll */ 7, /* kFastFlush */ 1, /* kLastFast */ 0); + break; + case 7: + HUF_compress1X_usingCTable_internal_body_loop(&bitC, ip, srcSize, ct, /* kUnroll */ 8, /* kFastFlush */ 1, /* kLastFast */ 0); + break; + case 6: ZSTD_FALLTHROUGH; + default: + HUF_compress1X_usingCTable_internal_body_loop(&bitC, ip, srcSize, ct, /* kUnroll */ 9, /* kFastFlush */ 1, /* kLastFast */ 1); + break; + } + } } + assert(bitC.ptr <= bitC.endPtr); - return BIT_closeCStream(&bitC); + return HUF_closeCStream(&bitC); } #if DYNAMIC_BMI2 -static TARGET_ATTRIBUTE("bmi2") size_t +static BMI2_TARGET_ATTRIBUTE size_t HUF_compress1X_usingCTable_internal_bmi2(void* dst, size_t dstSize, const void* src, size_t srcSize, const HUF_CElt* CTable) @@ -667,9 +1071,13 @@ HUF_compress1X_usingCTable_internal(void* dst, size_t dstSize, size_t HUF_compress1X_usingCTable(void* dst, size_t dstSize, const void* src, size_t srcSize, const HUF_CElt* CTable) { - return HUF_compress1X_usingCTable_internal(dst, dstSize, src, srcSize, CTable, /* bmi2 */ 0); + return HUF_compress1X_usingCTable_bmi2(dst, dstSize, src, srcSize, CTable, /* bmi2 */ 0); } +size_t HUF_compress1X_usingCTable_bmi2(void* dst, size_t dstSize, const void* src, size_t srcSize, const HUF_CElt* CTable, int bmi2) +{ + return HUF_compress1X_usingCTable_internal(dst, dstSize, src, srcSize, CTable, bmi2); +} static size_t HUF_compress4X_usingCTable_internal(void* dst, size_t dstSize, @@ -689,8 +1097,7 @@ HUF_compress4X_usingCTable_internal(void* dst, size_t dstSize, assert(op <= oend); { CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, segmentSize, CTable, bmi2) ); - if (cSize==0) return 0; - assert(cSize <= 65535); + if (cSize == 0 || cSize > 65535) return 0; MEM_writeLE16(ostart, (U16)cSize); op += cSize; } @@ -698,8 +1105,7 @@ HUF_compress4X_usingCTable_internal(void* dst, size_t dstSize, ip += segmentSize; assert(op <= oend); { CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, segmentSize, CTable, bmi2) ); - if (cSize==0) return 0; - assert(cSize <= 65535); + if (cSize == 0 || cSize > 65535) return 0; MEM_writeLE16(ostart+2, (U16)cSize); op += cSize; } @@ -707,8 +1113,7 @@ HUF_compress4X_usingCTable_internal(void* dst, size_t dstSize, ip += segmentSize; assert(op <= oend); { CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, segmentSize, CTable, bmi2) ); - if (cSize==0) return 0; - assert(cSize <= 65535); + if (cSize == 0 || cSize > 65535) return 0; MEM_writeLE16(ostart+4, (U16)cSize); op += cSize; } @@ -717,7 +1122,7 @@ HUF_compress4X_usingCTable_internal(void* dst, size_t dstSize, assert(op <= oend); assert(ip <= iend); { CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, (size_t)(iend-ip), CTable, bmi2) ); - if (cSize==0) return 0; + if (cSize == 0 || cSize > 65535) return 0; op += cSize; } @@ -726,7 +1131,12 @@ HUF_compress4X_usingCTable_internal(void* dst, size_t dstSize, size_t HUF_compress4X_usingCTable(void* dst, size_t dstSize, const void* src, size_t srcSize, const HUF_CElt* CTable) { - return HUF_compress4X_usingCTable_internal(dst, dstSize, src, srcSize, CTable, /* bmi2 */ 0); + return HUF_compress4X_usingCTable_bmi2(dst, dstSize, src, srcSize, CTable, /* bmi2 */ 0); +} + +size_t HUF_compress4X_usingCTable_bmi2(void* dst, size_t dstSize, const void* src, size_t srcSize, const HUF_CElt* CTable, int bmi2) +{ + return HUF_compress4X_usingCTable_internal(dst, dstSize, src, srcSize, CTable, bmi2); } typedef enum { HUF_singleStream, HUF_fourStreams } HUF_nbStreams_e; @@ -750,35 +1160,38 @@ static size_t HUF_compressCTable_internal( typedef struct { unsigned count[HUF_SYMBOLVALUE_MAX + 1]; - HUF_CElt CTable[HUF_SYMBOLVALUE_MAX + 1]; + HUF_CElt CTable[HUF_CTABLE_SIZE_ST(HUF_SYMBOLVALUE_MAX)]; union { HUF_buildCTable_wksp_tables buildCTable_wksp; HUF_WriteCTableWksp writeCTable_wksp; + U32 hist_wksp[HIST_WKSP_SIZE_U32]; } wksps; } HUF_compress_tables_t; +#define SUSPECT_INCOMPRESSIBLE_SAMPLE_SIZE 4096 +#define SUSPECT_INCOMPRESSIBLE_SAMPLE_RATIO 10 /* Must be >= 2 */ + /* HUF_compress_internal() : * `workSpace_align4` must be aligned on 4-bytes boundaries, - * and occupies the same space as a table of HUF_WORKSPACE_SIZE_U32 unsigned */ + * and occupies the same space as a table of HUF_WORKSPACE_SIZE_U64 unsigned */ static size_t HUF_compress_internal (void* dst, size_t dstSize, const void* src, size_t srcSize, unsigned maxSymbolValue, unsigned huffLog, HUF_nbStreams_e nbStreams, - void* workSpace_align4, size_t wkspSize, + void* workSpace, size_t wkspSize, HUF_CElt* oldHufTable, HUF_repeat* repeat, int preferRepeat, - const int bmi2) + const int bmi2, unsigned suspectUncompressible) { - HUF_compress_tables_t* const table = (HUF_compress_tables_t*)workSpace_align4; + HUF_compress_tables_t* const table = (HUF_compress_tables_t*)HUF_alignUpWorkspace(workSpace, &wkspSize, ZSTD_ALIGNOF(size_t)); BYTE* const ostart = (BYTE*)dst; BYTE* const oend = ostart + dstSize; BYTE* op = ostart; - HUF_STATIC_ASSERT(sizeof(*table) <= HUF_WORKSPACE_SIZE); - assert(((size_t)workSpace_align4 & 3) == 0); /* must be aligned on 4-bytes boundaries */ + HUF_STATIC_ASSERT(sizeof(*table) + HUF_WORKSPACE_MAX_ALIGNMENT <= HUF_WORKSPACE_SIZE); /* checks & inits */ - if (wkspSize < HUF_WORKSPACE_SIZE) return ERROR(workSpace_tooSmall); + if (wkspSize < sizeof(*table)) return ERROR(workSpace_tooSmall); if (!srcSize) return 0; /* Uncompressed */ if (!dstSize) return 0; /* cannot fit anything within dst budget */ if (srcSize > HUF_BLOCKSIZE_MAX) return ERROR(srcSize_wrong); /* current block size limit */ @@ -794,8 +1207,23 @@ HUF_compress_internal (void* dst, size_t dstSize, nbStreams, oldHufTable, bmi2); } + /* If uncompressible data is suspected, do a smaller sampling first */ + DEBUG_STATIC_ASSERT(SUSPECT_INCOMPRESSIBLE_SAMPLE_RATIO >= 2); + if (suspectUncompressible && srcSize >= (SUSPECT_INCOMPRESSIBLE_SAMPLE_SIZE * SUSPECT_INCOMPRESSIBLE_SAMPLE_RATIO)) { + size_t largestTotal = 0; + { unsigned maxSymbolValueBegin = maxSymbolValue; + CHECK_V_F(largestBegin, HIST_count_simple (table->count, &maxSymbolValueBegin, (const BYTE*)src, SUSPECT_INCOMPRESSIBLE_SAMPLE_SIZE) ); + largestTotal += largestBegin; + } + { unsigned maxSymbolValueEnd = maxSymbolValue; + CHECK_V_F(largestEnd, HIST_count_simple (table->count, &maxSymbolValueEnd, (const BYTE*)src + srcSize - SUSPECT_INCOMPRESSIBLE_SAMPLE_SIZE, SUSPECT_INCOMPRESSIBLE_SAMPLE_SIZE) ); + largestTotal += largestEnd; + } + if (largestTotal <= ((2 * SUSPECT_INCOMPRESSIBLE_SAMPLE_SIZE) >> 7)+4) return 0; /* heuristic : probably not compressible enough */ + } + /* Scan input and build symbol stats */ - { CHECK_V_F(largest, HIST_count_wksp (table->count, &maxSymbolValue, (const BYTE*)src, srcSize, workSpace_align4, wkspSize) ); + { CHECK_V_F(largest, HIST_count_wksp (table->count, &maxSymbolValue, (const BYTE*)src, srcSize, table->wksps.hist_wksp, sizeof(table->wksps.hist_wksp)) ); if (largest == srcSize) { *ostart = ((const BYTE*)src)[0]; return 1; } /* single symbol, rle */ if (largest <= (srcSize >> 7)+4) return 0; /* heuristic : probably not compressible enough */ } @@ -820,9 +1248,12 @@ HUF_compress_internal (void* dst, size_t dstSize, &table->wksps.buildCTable_wksp, sizeof(table->wksps.buildCTable_wksp)); CHECK_F(maxBits); huffLog = (U32)maxBits; - /* Zero unused symbols in CTable, so we can check it for validity */ - ZSTD_memset(table->CTable + (maxSymbolValue + 1), 0, - sizeof(table->CTable) - ((maxSymbolValue + 1) * sizeof(HUF_CElt))); + } + /* Zero unused symbols in CTable, so we can check it for validity */ + { + size_t const ctableSize = HUF_CTABLE_SIZE_ST(maxSymbolValue); + size_t const unusedSize = sizeof(table->CTable) - ctableSize * sizeof(HUF_CElt); + ZSTD_memset(table->CTable + ctableSize, 0, unusedSize); } /* Write table description header */ @@ -859,19 +1290,20 @@ size_t HUF_compress1X_wksp (void* dst, size_t dstSize, return HUF_compress_internal(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, HUF_singleStream, workSpace, wkspSize, - NULL, NULL, 0, 0 /*bmi2*/); + NULL, NULL, 0, 0 /*bmi2*/, 0); } size_t HUF_compress1X_repeat (void* dst, size_t dstSize, const void* src, size_t srcSize, unsigned maxSymbolValue, unsigned huffLog, void* workSpace, size_t wkspSize, - HUF_CElt* hufTable, HUF_repeat* repeat, int preferRepeat, int bmi2) + HUF_CElt* hufTable, HUF_repeat* repeat, int preferRepeat, + int bmi2, unsigned suspectUncompressible) { return HUF_compress_internal(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, HUF_singleStream, workSpace, wkspSize, hufTable, - repeat, preferRepeat, bmi2); + repeat, preferRepeat, bmi2, suspectUncompressible); } /* HUF_compress4X_repeat(): @@ -885,22 +1317,23 @@ size_t HUF_compress4X_wksp (void* dst, size_t dstSize, return HUF_compress_internal(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, HUF_fourStreams, workSpace, wkspSize, - NULL, NULL, 0, 0 /*bmi2*/); + NULL, NULL, 0, 0 /*bmi2*/, 0); } /* HUF_compress4X_repeat(): * compress input using 4 streams. + * consider skipping quickly * re-use an existing huffman compression table */ size_t HUF_compress4X_repeat (void* dst, size_t dstSize, const void* src, size_t srcSize, unsigned maxSymbolValue, unsigned huffLog, void* workSpace, size_t wkspSize, - HUF_CElt* hufTable, HUF_repeat* repeat, int preferRepeat, int bmi2) + HUF_CElt* hufTable, HUF_repeat* repeat, int preferRepeat, int bmi2, unsigned suspectUncompressible) { return HUF_compress_internal(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, HUF_fourStreams, workSpace, wkspSize, - hufTable, repeat, preferRepeat, bmi2); + hufTable, repeat, preferRepeat, bmi2, suspectUncompressible); } #ifndef ZSTD_NO_UNUSED_FUNCTIONS @@ -918,7 +1351,7 @@ size_t HUF_compress1X (void* dst, size_t dstSize, const void* src, size_t srcSize, unsigned maxSymbolValue, unsigned huffLog) { - unsigned workSpace[HUF_WORKSPACE_SIZE_U32]; + U64 workSpace[HUF_WORKSPACE_SIZE_U64]; return HUF_compress1X_wksp(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, workSpace, sizeof(workSpace)); } @@ -926,7 +1359,7 @@ size_t HUF_compress2 (void* dst, size_t dstSize, const void* src, size_t srcSize, unsigned maxSymbolValue, unsigned huffLog) { - unsigned workSpace[HUF_WORKSPACE_SIZE_U32]; + U64 workSpace[HUF_WORKSPACE_SIZE_U64]; return HUF_compress4X_wksp(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, workSpace, sizeof(workSpace)); } |