| /* ****************************************************************** |
| * Huffman encoder, part of New Generation Entropy library |
| * Copyright (c) Meta Platforms, Inc. and affiliates. |
| * |
| * You can contact the author at : |
| * - FSE+HUF source repository : https://github.com/Cyan4973/FiniteStateEntropy |
| * - Public forum : https://groups.google.com/forum/#!forum/lz4c |
| * |
| * This source code is licensed under both the BSD-style license (found in the |
| * LICENSE file in the root directory of this source tree) and the GPLv2 (found |
| * in the COPYING file in the root directory of this source tree). |
| * You may select, at your option, one of the above-listed licenses. |
| ****************************************************************** */ |
| |
| /* ************************************************************** |
| * Compiler specifics |
| ****************************************************************/ |
| #ifdef _MSC_VER /* Visual Studio */ |
| # pragma warning(disable : 4127) /* disable: C4127: conditional expression is constant */ |
| #endif |
| |
| |
| /* ************************************************************** |
| * Includes |
| ****************************************************************/ |
| #include "../common/zstd_deps.h" /* ZSTD_memcpy, ZSTD_memset */ |
| #include "../common/compiler.h" |
| #include "../common/bitstream.h" |
| #include "hist.h" |
| #define FSE_STATIC_LINKING_ONLY /* FSE_optimalTableLog_internal */ |
| #include "../common/fse.h" /* header compression */ |
| #include "../common/huf.h" |
| #include "../common/error_private.h" |
| #include "../common/bits.h" /* ZSTD_highbit32 */ |
| |
| |
| /* ************************************************************** |
| * Error Management |
| ****************************************************************/ |
| #define HUF_isError ERR_isError |
| #define HUF_STATIC_ASSERT(c) DEBUG_STATIC_ASSERT(c) /* use only *after* variable declarations */ |
| |
| |
| /* ************************************************************** |
| * Required declarations |
| ****************************************************************/ |
| typedef struct nodeElt_s { |
| U32 count; |
| U16 parent; |
| BYTE byte; |
| BYTE nbBits; |
| } nodeElt; |
| |
| |
| /* ************************************************************** |
| * Debug Traces |
| ****************************************************************/ |
| |
| #if DEBUGLEVEL >= 2 |
| |
| static size_t showU32(const U32* arr, size_t size) |
| { |
| size_t u; |
| for (u=0; u<size; u++) { |
| RAWLOG(6, " %u", arr[u]); (void)arr; |
| } |
| RAWLOG(6, " \n"); |
| return size; |
| } |
| |
| static size_t HUF_getNbBits(HUF_CElt elt); |
| |
| static size_t showCTableBits(const HUF_CElt* ctable, size_t size) |
| { |
| size_t u; |
| for (u=0; u<size; u++) { |
| RAWLOG(6, " %zu", HUF_getNbBits(ctable[u])); (void)ctable; |
| } |
| RAWLOG(6, " \n"); |
| return size; |
| |
| } |
| |
| static size_t showHNodeSymbols(const nodeElt* hnode, size_t size) |
| { |
| size_t u; |
| for (u=0; u<size; u++) { |
| RAWLOG(6, " %u", hnode[u].byte); (void)hnode; |
| } |
| RAWLOG(6, " \n"); |
| return size; |
| } |
| |
| static size_t showHNodeBits(const nodeElt* hnode, size_t size) |
| { |
| size_t u; |
| for (u=0; u<size; u++) { |
| RAWLOG(6, " %u", hnode[u].nbBits); (void)hnode; |
| } |
| RAWLOG(6, " \n"); |
| return size; |
| } |
| |
| #endif |
| |
| |
| /* ******************************************************* |
| * 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. |
| * Note : all elements within weightTable are supposed to be <= HUF_TABLELOG_MAX. |
| */ |
| #define MAX_FSE_TABLELOG_FOR_HUFF_HEADER 6 |
| |
| typedef struct { |
| FSE_CTable CTable[FSE_CTABLE_SIZE_U32(MAX_FSE_TABLELOG_FOR_HUFF_HEADER, HUF_TABLELOG_MAX)]; |
| U32 scratchBuffer[FSE_BUILD_CTABLE_WORKSPACE_SIZE_U32(HUF_TABLELOG_MAX, MAX_FSE_TABLELOG_FOR_HUFF_HEADER)]; |
| unsigned count[HUF_TABLELOG_MAX+1]; |
| S16 norm[HUF_TABLELOG_MAX+1]; |
| } HUF_CompressWeightsWksp; |
| |
| static size_t |
| HUF_compressWeights(void* dst, size_t dstSize, |
| const void* weightTable, size_t wtSize, |
| void* workspace, size_t workspaceSize) |
| { |
| BYTE* const ostart = (BYTE*) dst; |
| BYTE* op = ostart; |
| BYTE* const oend = ostart + dstSize; |
| |
| unsigned maxSymbolValue = HUF_TABLELOG_MAX; |
| U32 tableLog = MAX_FSE_TABLELOG_FOR_HUFF_HEADER; |
| HUF_CompressWeightsWksp* wksp = (HUF_CompressWeightsWksp*)HUF_alignUpWorkspace(workspace, &workspaceSize, ZSTD_ALIGNOF(U32)); |
| |
| if (workspaceSize < sizeof(HUF_CompressWeightsWksp)) return ERROR(GENERIC); |
| |
| /* init conditions */ |
| if (wtSize <= 1) return 0; /* Not compressible */ |
| |
| /* Scan input and build symbol stats */ |
| { unsigned const maxCount = HIST_count_simple(wksp->count, &maxSymbolValue, weightTable, wtSize); /* never fails */ |
| if (maxCount == wtSize) return 1; /* only a single symbol in src : rle */ |
| if (maxCount == 1) return 0; /* each symbol present maximum once => not compressible */ |
| } |
| |
| tableLog = FSE_optimalTableLog(tableLog, wtSize, maxSymbolValue); |
| CHECK_F( FSE_normalizeCount(wksp->norm, tableLog, wksp->count, wtSize, maxSymbolValue, /* useLowProbCount */ 0) ); |
| |
| /* Write table description header */ |
| { CHECK_V_F(hSize, FSE_writeNCount(op, (size_t)(oend-op), wksp->norm, maxSymbolValue, tableLog) ); |
| op += hSize; |
| } |
| |
| /* Compress */ |
| CHECK_F( FSE_buildCTable_wksp(wksp->CTable, wksp->norm, maxSymbolValue, tableLog, wksp->scratchBuffer, sizeof(wksp->scratchBuffer)) ); |
| { CHECK_V_F(cSize, FSE_compress_usingCTable(op, (size_t)(oend - op), weightTable, wtSize, wksp->CTable) ); |
| if (cSize == 0) return 0; /* not enough space for compressed data */ |
| op += cSize; |
| } |
| |
| 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 & ~(size_t)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; |
| BYTE bitsToWeight[HUF_TABLELOG_MAX + 1]; /* precomputed conversion table */ |
| BYTE huffWeight[HUF_SYMBOLVALUE_MAX]; |
| } HUF_WriteCTableWksp; |
| |
| 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*)HUF_alignUpWorkspace(workspace, &workspaceSize, ZSTD_ALIGNOF(U32)); |
| |
| HUF_STATIC_ASSERT(HUF_CTABLE_WORKSPACE_SIZE >= sizeof(HUF_WriteCTableWksp)); |
| |
| /* check conditions */ |
| if (workspaceSize < sizeof(HUF_WriteCTableWksp)) return ERROR(GENERIC); |
| if (maxSymbolValue > HUF_SYMBOLVALUE_MAX) return ERROR(maxSymbolValue_tooLarge); |
| |
| /* convert to weight */ |
| wksp->bitsToWeight[0] = 0; |
| 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[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; |
| return hSize+1; |
| } } |
| |
| /* write raw values as 4-bits (max : 15) */ |
| if (maxSymbolValue > (256-128)) return ERROR(GENERIC); /* should not happen : likely means source cannot be compressed */ |
| if (((maxSymbolValue+1)/2) + 1 > maxDstSize) return ERROR(dstSize_tooSmall); /* not enough space within dst buffer */ |
| op[0] = (BYTE)(128 /*special case*/ + (maxSymbolValue-1)); |
| wksp->huffWeight[maxSymbolValue] = 0; /* to be sure it doesn't cause msan issue in final combination */ |
| for (n=0; n<maxSymbolValue; n+=2) |
| op[(n/2)+1] = (BYTE)((wksp->huffWeight[n] << 4) + wksp->huffWeight[n+1]); |
| return ((maxSymbolValue+1)/2) + 1; |
| } |
| |
| |
| size_t HUF_readCTable (HUF_CElt* CTable, unsigned* maxSymbolValuePtr, const void* src, size_t srcSize, unsigned* hasZeroWeights) |
| { |
| BYTE huffWeight[HUF_SYMBOLVALUE_MAX + 1]; /* init not required, even though some static analyzer may complain */ |
| 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)); |
| *hasZeroWeights = (rankVal[0] > 0); |
| |
| /* check result */ |
| 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++) { |
| U32 curr = nextRankStart; |
| nextRankStart += (rankVal[n] << (n-1)); |
| rankVal[n] = curr; |
| } } |
| |
| /* fill nbBits */ |
| { U32 n; for (n=0; n<nbSymbols; n++) { |
| const U32 w = huffWeight[n]; |
| 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[HUF_getNbBits(ct[n])]++; } |
| /* determine stating value per rank */ |
| valPerRank[tableLog+1] = 0; /* for w==0 */ |
| { U16 min = 0; |
| U32 n; for (n=tableLog; n>0; n--) { /* start at n=tablelog <-> w=1 */ |
| valPerRank[n] = min; /* get starting value within each rank */ |
| min += nbPerRank[n]; |
| min >>= 1; |
| } } |
| /* assign value within rank, symbol order */ |
| { U32 n; for (n=0; n<nbSymbols; n++) HUF_setValue(ct + n, valPerRank[HUF_getNbBits(ct[n])]++); } |
| } |
| |
| *maxSymbolValuePtr = nbSymbols - 1; |
| return readSize; |
| } |
| |
| U32 HUF_getNbBitsFromCTable(HUF_CElt const* CTable, U32 symbolValue) |
| { |
| const HUF_CElt* const ct = CTable + 1; |
| assert(symbolValue <= HUF_SYMBOLVALUE_MAX); |
| return (U32)HUF_getNbBits(ct[symbolValue]); |
| } |
| |
| |
| /** |
| * HUF_setMaxHeight(): |
| * Try to enforce @targetNbBits on the Huffman tree described in @huffNode. |
| * |
| * It attempts to convert all nodes with nbBits > @targetNbBits |
| * to employ @targetNbBits instead. Then it adjusts the tree |
| * so that it remains a valid canonical Huffman tree. |
| * |
| * @pre The sum of the ranks of each symbol == 2^largestBits, |
| * where largestBits == huffNode[lastNonNull].nbBits. |
| * @post The sum of the ranks of each symbol == 2^largestBits, |
| * where largestBits is the return value (expected <= targetNbBits). |
| * |
| * @param huffNode The Huffman tree modified in place to enforce targetNbBits. |
| * It's presumed sorted, from most frequent to rarest symbol. |
| * @param lastNonNull The symbol with the lowest count in the Huffman tree. |
| * @param targetNbBits The allowed number of bits, which the Huffman tree |
| * may not respect. After this function the Huffman tree will |
| * respect targetNbBits. |
| * @return The maximum number of bits of the Huffman tree after adjustment. |
| */ |
| static U32 HUF_setMaxHeight(nodeElt* huffNode, U32 lastNonNull, U32 targetNbBits) |
| { |
| const U32 largestBits = huffNode[lastNonNull].nbBits; |
| /* early exit : no elt > targetNbBits, so the tree is already valid. */ |
| if (largestBits <= targetNbBits) return largestBits; |
| |
| DEBUGLOG(5, "HUF_setMaxHeight (targetNbBits = %u)", targetNbBits); |
| |
| /* there are several too large elements (at least >= 2) */ |
| { int totalCost = 0; |
| const U32 baseCost = 1 << (largestBits - targetNbBits); |
| int n = (int)lastNonNull; |
| |
| /* Adjust any ranks > targetNbBits to targetNbBits. |
| * Compute totalCost, which is how far the sum of the ranks is |
| * we are over 2^largestBits after adjust the offending ranks. |
| */ |
| while (huffNode[n].nbBits > targetNbBits) { |
| totalCost += baseCost - (1 << (largestBits - huffNode[n].nbBits)); |
| huffNode[n].nbBits = (BYTE)targetNbBits; |
| n--; |
| } |
| /* n stops at huffNode[n].nbBits <= targetNbBits */ |
| assert(huffNode[n].nbBits <= targetNbBits); |
| /* n end at index of smallest symbol using < targetNbBits */ |
| while (huffNode[n].nbBits == targetNbBits) --n; |
| |
| /* renorm totalCost from 2^largestBits to 2^targetNbBits |
| * note : totalCost is necessarily a multiple of baseCost */ |
| assert(((U32)totalCost & (baseCost - 1)) == 0); |
| totalCost >>= (largestBits - targetNbBits); |
| assert(totalCost > 0); |
| |
| /* repay normalized cost */ |
| { U32 const noSymbol = 0xF0F0F0F0; |
| U32 rankLast[HUF_TABLELOG_MAX+2]; |
| |
| /* Get pos of last (smallest = lowest cum. count) symbol per rank */ |
| ZSTD_memset(rankLast, 0xF0, sizeof(rankLast)); |
| { U32 currentNbBits = targetNbBits; |
| int pos; |
| for (pos=n ; pos >= 0; pos--) { |
| if (huffNode[pos].nbBits >= currentNbBits) continue; |
| currentNbBits = huffNode[pos].nbBits; /* < targetNbBits */ |
| rankLast[targetNbBits-currentNbBits] = (U32)pos; |
| } } |
| |
| while (totalCost > 0) { |
| /* Try to reduce the next power of 2 above totalCost because we |
| * gain back half the rank. |
| */ |
| U32 nBitsToDecrease = ZSTD_highbit32((U32)totalCost) + 1; |
| for ( ; nBitsToDecrease > 1; nBitsToDecrease--) { |
| U32 const highPos = rankLast[nBitsToDecrease]; |
| U32 const lowPos = rankLast[nBitsToDecrease-1]; |
| if (highPos == noSymbol) continue; |
| /* Decrease highPos if no symbols of lowPos or if it is |
| * not cheaper to remove 2 lowPos than highPos. |
| */ |
| if (lowPos == noSymbol) break; |
| { U32 const highTotal = huffNode[highPos].count; |
| U32 const lowTotal = 2 * huffNode[lowPos].count; |
| if (highTotal <= lowTotal) break; |
| } } |
| /* only triggered when no more rank 1 symbol left => find closest one (note : there is necessarily at least one !) */ |
| assert(rankLast[nBitsToDecrease] != noSymbol || nBitsToDecrease == 1); |
| /* HUF_MAX_TABLELOG test just to please gcc 5+; but it should not be necessary */ |
| while ((nBitsToDecrease<=HUF_TABLELOG_MAX) && (rankLast[nBitsToDecrease] == noSymbol)) |
| nBitsToDecrease++; |
| assert(rankLast[nBitsToDecrease] != noSymbol); |
| /* Increase the number of bits to gain back half the rank cost. */ |
| totalCost -= 1 << (nBitsToDecrease-1); |
| huffNode[rankLast[nBitsToDecrease]].nbBits++; |
| |
| /* Fix up the new rank. |
| * If the new rank was empty, this symbol is now its smallest. |
| * Otherwise, this symbol will be the largest in the new rank so no adjustment. |
| */ |
| if (rankLast[nBitsToDecrease-1] == noSymbol) |
| rankLast[nBitsToDecrease-1] = rankLast[nBitsToDecrease]; |
| /* Fix up the old rank. |
| * If the symbol was at position 0, meaning it was the highest weight symbol in the tree, |
| * it must be the only symbol in its rank, so the old rank now has no symbols. |
| * Otherwise, since the Huffman nodes are sorted by count, the previous position is now |
| * the smallest node in the rank. If the previous position belongs to a different rank, |
| * then the rank is now empty. |
| */ |
| if (rankLast[nBitsToDecrease] == 0) /* special case, reached largest symbol */ |
| rankLast[nBitsToDecrease] = noSymbol; |
| else { |
| rankLast[nBitsToDecrease]--; |
| if (huffNode[rankLast[nBitsToDecrease]].nbBits != targetNbBits-nBitsToDecrease) |
| rankLast[nBitsToDecrease] = noSymbol; /* this rank is now empty */ |
| } |
| } /* while (totalCost > 0) */ |
| |
| /* If we've removed too much weight, then we have to add it back. |
| * To avoid overshooting again, we only adjust the smallest rank. |
| * We take the largest nodes from the lowest rank 0 and move them |
| * to rank 1. There's guaranteed to be enough rank 0 symbols because |
| * TODO. |
| */ |
| while (totalCost < 0) { /* Sometimes, cost correction overshoot */ |
| /* special case : no rank 1 symbol (using targetNbBits-1); |
| * let's create one from largest rank 0 (using targetNbBits). |
| */ |
| if (rankLast[1] == noSymbol) { |
| while (huffNode[n].nbBits == targetNbBits) n--; |
| huffNode[n+1].nbBits--; |
| assert(n >= 0); |
| rankLast[1] = (U32)(n+1); |
| totalCost++; |
| continue; |
| } |
| huffNode[ rankLast[1] + 1 ].nbBits--; |
| rankLast[1]++; |
| totalCost ++; |
| } |
| } /* repay normalized cost */ |
| } /* there are several too large elements (at least >= 2) */ |
| |
| return targetNbBits; |
| } |
| |
| typedef struct { |
| U16 base; |
| U16 curr; |
| } rankPos; |
| |
| typedef nodeElt huffNodeTable[2 * (HUF_SYMBOLVALUE_MAX + 1)]; |
| |
| /* 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 + ZSTD_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 |
| : ZSTD_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. |
| * @param[in] count Histogram of the symbols. |
| * @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 const maxSymbolValue, rankPos rankPosition[]) { |
| U32 n; |
| U32 const maxSymbolValue1 = maxSymbolValue+1; |
| |
| /* Compute base and set curr to base. |
| * 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 = 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; |
| } |
| |
| /* 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 = 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) { |
| int 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. |
| * `workSpace` must be aligned on 4-bytes boundaries, and be at least as large as sizeof(HUF_buildCTable_wksp_tables). |
| */ |
| #define STARTNODE (HUF_SYMBOLVALUE_MAX+1) |
| |
| /* HUF_buildTree(): |
| * Takes the huffNode array sorted by HUF_sort() and builds an unlimited-depth Huffman tree. |
| * |
| * @param huffNode The array sorted by HUF_sort(). Builds the Huffman tree in this array. |
| * @param maxSymbolValue The maximum symbol value. |
| * @return The smallest node in the Huffman tree (by count). |
| */ |
| static int HUF_buildTree(nodeElt* huffNode, U32 maxSymbolValue) |
| { |
| nodeElt* const huffNode0 = huffNode - 1; |
| int nonNullRank; |
| int lowS, lowN; |
| int nodeNb = STARTNODE; |
| int n, nodeRoot; |
| DEBUGLOG(5, "HUF_buildTree (alphabet size = %u)", maxSymbolValue + 1); |
| /* init for parents */ |
| nonNullRank = (int)maxSymbolValue; |
| while(huffNode[nonNullRank].count == 0) nonNullRank--; |
| lowS = nonNullRank; nodeRoot = nodeNb + lowS - 1; lowN = nodeNb; |
| huffNode[nodeNb].count = huffNode[lowS].count + huffNode[lowS-1].count; |
| huffNode[lowS].parent = huffNode[lowS-1].parent = (U16)nodeNb; |
| nodeNb++; lowS-=2; |
| for (n=nodeNb; n<=nodeRoot; n++) huffNode[n].count = (U32)(1U<<30); |
| huffNode0[0].count = (U32)(1U<<31); /* fake entry, strong barrier */ |
| |
| /* create parents */ |
| while (nodeNb <= nodeRoot) { |
| int const n1 = (huffNode[lowS].count < huffNode[lowN].count) ? lowS-- : lowN++; |
| int const n2 = (huffNode[lowS].count < huffNode[lowN].count) ? lowS-- : lowN++; |
| huffNode[nodeNb].count = huffNode[n1].count + huffNode[n2].count; |
| huffNode[n1].parent = huffNode[n2].parent = (U16)nodeNb; |
| nodeNb++; |
| } |
| |
| /* distribute weights (unlimited tree height) */ |
| huffNode[nodeRoot].nbBits = 0; |
| for (n=nodeRoot-1; n>=STARTNODE; n--) |
| huffNode[n].nbBits = huffNode[ huffNode[n].parent ].nbBits + 1; |
| for (n=0; n<=nonNullRank; n++) |
| huffNode[n].nbBits = huffNode[ huffNode[n].parent ].nbBits + 1; |
| |
| DEBUGLOG(6, "Initial distribution of bits completed (%zu sorted symbols)", showHNodeBits(huffNode, maxSymbolValue+1)); |
| |
| return nonNullRank; |
| } |
| |
| /** |
| * HUF_buildCTableFromTree(): |
| * Build the CTable given the Huffman tree in huffNode. |
| * |
| * @param[out] CTable The output Huffman CTable. |
| * @param huffNode The Huffman tree. |
| * @param nonNullRank The last and smallest node in the Huffman tree. |
| * @param maxSymbolValue The maximum symbol value. |
| * @param maxNbBits The exact maximum number of bits used in the Huffman tree. |
| */ |
| 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}; |
| U16 valPerRank[HUF_TABLELOG_MAX+1] = {0}; |
| int const alphabetSize = (int)(maxSymbolValue + 1); |
| for (n=0; n<=nonNullRank; n++) |
| nbPerRank[huffNode[n].nbBits]++; |
| /* determine starting value per rank */ |
| { U16 min = 0; |
| for (n=(int)maxNbBits; n>0; n--) { |
| valPerRank[n] = min; /* get starting value within each rank */ |
| min += nbPerRank[n]; |
| min >>= 1; |
| } } |
| for (n=0; n<alphabetSize; n++) |
| HUF_setNbBits(ct + huffNode[n].byte, huffNode[n].nbBits); /* push nbBits per symbol, symbol order */ |
| for (n=0; n<alphabetSize; n++) |
| 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* CTable, const unsigned* count, U32 maxSymbolValue, U32 maxNbBits, |
| void* workSpace, size_t wkspSize) |
| { |
| 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; |
| |
| HUF_STATIC_ASSERT(HUF_CTABLE_WORKSPACE_SIZE == sizeof(HUF_buildCTable_wksp_tables)); |
| |
| DEBUGLOG(5, "HUF_buildCTable_wksp (alphabet size = %u)", maxSymbolValue+1); |
| |
| /* safety checks */ |
| if (wkspSize < sizeof(HUF_buildCTable_wksp_tables)) |
| return ERROR(workSpace_tooSmall); |
| if (maxNbBits == 0) maxNbBits = HUF_TABLELOG_DEFAULT; |
| if (maxSymbolValue > HUF_SYMBOLVALUE_MAX) |
| return ERROR(maxSymbolValue_tooLarge); |
| ZSTD_memset(huffNode0, 0, sizeof(huffNodeTable)); |
| |
| /* sort, decreasing order */ |
| HUF_sort(huffNode, count, maxSymbolValue, wksp_tables->rankPosition); |
| DEBUGLOG(6, "sorted symbols completed (%zu symbols)", showHNodeSymbols(huffNode, maxSymbolValue+1)); |
| |
| /* build tree */ |
| nonNullRank = HUF_buildTree(huffNode, maxSymbolValue); |
| |
| /* determine and enforce maxTableLog */ |
| maxNbBits = HUF_setMaxHeight(huffNode, (U32)nonNullRank, maxNbBits); |
| if (maxNbBits > HUF_TABLELOG_MAX) return ERROR(GENERIC); /* check fit into table */ |
| |
| 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 += 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) & (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 : ZSTD_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 (size_t)(bitC->ptr - bitC->startPtr) + (nbBits > 0); |
| } |
| } |
| |
| FORCE_INLINE_TEMPLATE void |
| HUF_encodeSymbol(HUF_CStream_t* bitCPtr, U32 symbol, const HUF_CElt* CTable, int idx, int fast) |
| { |
| HUF_addBits(bitCPtr, CTable[symbol], idx, fast); |
| } |
| |
| 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); |
| |
| } |
| |
| /** |
| * 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; |
| } |
| |
| |
| 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; |
| HUF_CStream_t bitC; |
| |
| /* init */ |
| if (dstSize < 8) return 0; /* not enough space to compress */ |
| { size_t const initErr = HUF_initCStream(&bitC, op, (size_t)(oend-op)); |
| if (HUF_isError(initErr)) return 0; } |
| |
| 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 HUF_closeCStream(&bitC); |
| } |
| |
| #if DYNAMIC_BMI2 |
| |
| 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) |
| { |
| return HUF_compress1X_usingCTable_internal_body(dst, dstSize, src, srcSize, CTable); |
| } |
| |
| static size_t |
| HUF_compress1X_usingCTable_internal_default(void* dst, size_t dstSize, |
| const void* src, size_t srcSize, |
| const HUF_CElt* CTable) |
| { |
| return HUF_compress1X_usingCTable_internal_body(dst, dstSize, src, srcSize, CTable); |
| } |
| |
| static size_t |
| HUF_compress1X_usingCTable_internal(void* dst, size_t dstSize, |
| const void* src, size_t srcSize, |
| const HUF_CElt* CTable, const int flags) |
| { |
| if (flags & HUF_flags_bmi2) { |
| return HUF_compress1X_usingCTable_internal_bmi2(dst, dstSize, src, srcSize, CTable); |
| } |
| return HUF_compress1X_usingCTable_internal_default(dst, dstSize, src, srcSize, CTable); |
| } |
| |
| #else |
| |
| static size_t |
| HUF_compress1X_usingCTable_internal(void* dst, size_t dstSize, |
| const void* src, size_t srcSize, |
| const HUF_CElt* CTable, const int flags) |
| { |
| (void)flags; |
| return HUF_compress1X_usingCTable_internal_body(dst, dstSize, src, srcSize, CTable); |
| } |
| |
| #endif |
| |
| size_t HUF_compress1X_usingCTable(void* dst, size_t dstSize, const void* src, size_t srcSize, const HUF_CElt* CTable, int flags) |
| { |
| return HUF_compress1X_usingCTable_internal(dst, dstSize, src, srcSize, CTable, flags); |
| } |
| |
| static size_t |
| HUF_compress4X_usingCTable_internal(void* dst, size_t dstSize, |
| const void* src, size_t srcSize, |
| const HUF_CElt* CTable, int flags) |
| { |
| size_t const segmentSize = (srcSize+3)/4; /* first 3 segments */ |
| const BYTE* ip = (const BYTE*) src; |
| const BYTE* const iend = ip + srcSize; |
| BYTE* const ostart = (BYTE*) dst; |
| BYTE* const oend = ostart + dstSize; |
| BYTE* op = ostart; |
| |
| if (dstSize < 6 + 1 + 1 + 1 + 8) return 0; /* minimum space to compress successfully */ |
| if (srcSize < 12) return 0; /* no saving possible : too small input */ |
| op += 6; /* jumpTable */ |
| |
| assert(op <= oend); |
| { CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, segmentSize, CTable, flags) ); |
| if (cSize == 0 || cSize > 65535) return 0; |
| MEM_writeLE16(ostart, (U16)cSize); |
| op += cSize; |
| } |
| |
| ip += segmentSize; |
| assert(op <= oend); |
| { CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, segmentSize, CTable, flags) ); |
| if (cSize == 0 || cSize > 65535) return 0; |
| MEM_writeLE16(ostart+2, (U16)cSize); |
| op += cSize; |
| } |
| |
| ip += segmentSize; |
| assert(op <= oend); |
| { CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, segmentSize, CTable, flags) ); |
| if (cSize == 0 || cSize > 65535) return 0; |
| MEM_writeLE16(ostart+4, (U16)cSize); |
| op += cSize; |
| } |
| |
| ip += segmentSize; |
| 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, flags) ); |
| if (cSize == 0 || cSize > 65535) return 0; |
| op += cSize; |
| } |
| |
| return (size_t)(op-ostart); |
| } |
| |
| size_t HUF_compress4X_usingCTable(void* dst, size_t dstSize, const void* src, size_t srcSize, const HUF_CElt* CTable, int flags) |
| { |
| return HUF_compress4X_usingCTable_internal(dst, dstSize, src, srcSize, CTable, flags); |
| } |
| |
| typedef enum { HUF_singleStream, HUF_fourStreams } HUF_nbStreams_e; |
| |
| static size_t HUF_compressCTable_internal( |
| BYTE* const ostart, BYTE* op, BYTE* const oend, |
| const void* src, size_t srcSize, |
| HUF_nbStreams_e nbStreams, const HUF_CElt* CTable, const int flags) |
| { |
| size_t const cSize = (nbStreams==HUF_singleStream) ? |
| HUF_compress1X_usingCTable_internal(op, (size_t)(oend - op), src, srcSize, CTable, flags) : |
| HUF_compress4X_usingCTable_internal(op, (size_t)(oend - op), src, srcSize, CTable, flags); |
| if (HUF_isError(cSize)) { return cSize; } |
| if (cSize==0) { return 0; } /* uncompressible */ |
| op += cSize; |
| /* check compressibility */ |
| assert(op >= ostart); |
| if ((size_t)(op-ostart) >= srcSize-1) { return 0; } |
| return (size_t)(op-ostart); |
| } |
| |
| typedef struct { |
| unsigned count[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 */ |
| |
| unsigned HUF_cardinality(const unsigned* count, unsigned maxSymbolValue) |
| { |
| unsigned cardinality = 0; |
| unsigned i; |
| |
| for (i = 0; i < maxSymbolValue + 1; i++) { |
| if (count[i] != 0) cardinality += 1; |
| } |
| |
| return cardinality; |
| } |
| |
| unsigned HUF_minTableLog(unsigned symbolCardinality) |
| { |
| U32 minBitsSymbols = ZSTD_highbit32(symbolCardinality) + 1; |
| return minBitsSymbols; |
| } |
| |
| unsigned HUF_optimalTableLog( |
| unsigned maxTableLog, |
| size_t srcSize, |
| unsigned maxSymbolValue, |
| void* workSpace, size_t wkspSize, |
| HUF_CElt* table, |
| const unsigned* count, |
| int flags) |
| { |
| assert(srcSize > 1); /* Not supported, RLE should be used instead */ |
| assert(wkspSize >= sizeof(HUF_buildCTable_wksp_tables)); |
| |
| if (!(flags & HUF_flags_optimalDepth)) { |
| /* cheap evaluation, based on FSE */ |
| return FSE_optimalTableLog_internal(maxTableLog, srcSize, maxSymbolValue, 1); |
| } |
| |
| { BYTE* dst = (BYTE*)workSpace + sizeof(HUF_WriteCTableWksp); |
| size_t dstSize = wkspSize - sizeof(HUF_WriteCTableWksp); |
| size_t maxBits, hSize, newSize; |
| const unsigned symbolCardinality = HUF_cardinality(count, maxSymbolValue); |
| const unsigned minTableLog = HUF_minTableLog(symbolCardinality); |
| size_t optSize = ((size_t) ~0) - 1; |
| unsigned optLog = maxTableLog, optLogGuess; |
| |
| DEBUGLOG(6, "HUF_optimalTableLog: probing huf depth (srcSize=%zu)", srcSize); |
| |
| /* Search until size increases */ |
| for (optLogGuess = minTableLog; optLogGuess <= maxTableLog; optLogGuess++) { |
| DEBUGLOG(7, "checking for huffLog=%u", optLogGuess); |
| maxBits = HUF_buildCTable_wksp(table, count, maxSymbolValue, optLogGuess, workSpace, wkspSize); |
| if (ERR_isError(maxBits)) continue; |
| |
| if (maxBits < optLogGuess && optLogGuess > minTableLog) break; |
| |
| hSize = HUF_writeCTable_wksp(dst, dstSize, table, maxSymbolValue, (U32)maxBits, workSpace, wkspSize); |
| |
| if (ERR_isError(hSize)) continue; |
| |
| newSize = HUF_estimateCompressedSize(table, count, maxSymbolValue) + hSize; |
| |
| if (newSize > optSize + 1) { |
| break; |
| } |
| |
| if (newSize < optSize) { |
| optSize = newSize; |
| optLog = optLogGuess; |
| } |
| } |
| assert(optLog <= HUF_TABLELOG_MAX); |
| return optLog; |
| } |
| } |
| |
| /* HUF_compress_internal() : |
| * `workSpace_align4` must be aligned on 4-bytes boundaries, |
| * 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, size_t wkspSize, |
| HUF_CElt* oldHufTable, HUF_repeat* repeat, int flags) |
| { |
| 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; |
| |
| DEBUGLOG(5, "HUF_compress_internal (srcSize=%zu)", srcSize); |
| HUF_STATIC_ASSERT(sizeof(*table) + HUF_WORKSPACE_MAX_ALIGNMENT <= HUF_WORKSPACE_SIZE); |
| |
| /* checks & inits */ |
| 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 */ |
| if (huffLog > HUF_TABLELOG_MAX) return ERROR(tableLog_tooLarge); |
| if (maxSymbolValue > HUF_SYMBOLVALUE_MAX) return ERROR(maxSymbolValue_tooLarge); |
| if (!maxSymbolValue) maxSymbolValue = HUF_SYMBOLVALUE_MAX; |
| if (!huffLog) huffLog = HUF_TABLELOG_DEFAULT; |
| |
| /* Heuristic : If old table is valid, use it for small inputs */ |
| if ((flags & HUF_flags_preferRepeat) && repeat && *repeat == HUF_repeat_valid) { |
| return HUF_compressCTable_internal(ostart, op, oend, |
| src, srcSize, |
| nbStreams, oldHufTable, flags); |
| } |
| |
| /* If uncompressible data is suspected, do a smaller sampling first */ |
| DEBUG_STATIC_ASSERT(SUSPECT_INCOMPRESSIBLE_SAMPLE_RATIO >= 2); |
| if ((flags & HUF_flags_suspectUncompressible) && srcSize >= (SUSPECT_INCOMPRESSIBLE_SAMPLE_SIZE * SUSPECT_INCOMPRESSIBLE_SAMPLE_RATIO)) { |
| size_t largestTotal = 0; |
| DEBUGLOG(5, "input suspected incompressible : sampling to check"); |
| { 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, 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 */ |
| } |
| DEBUGLOG(6, "histogram detail completed (%zu symbols)", showU32(table->count, maxSymbolValue+1)); |
| |
| /* Check validity of previous table */ |
| if ( repeat |
| && *repeat == HUF_repeat_check |
| && !HUF_validateCTable(oldHufTable, table->count, maxSymbolValue)) { |
| *repeat = HUF_repeat_none; |
| } |
| /* Heuristic : use existing table for small inputs */ |
| if ((flags & HUF_flags_preferRepeat) && repeat && *repeat != HUF_repeat_none) { |
| return HUF_compressCTable_internal(ostart, op, oend, |
| src, srcSize, |
| nbStreams, oldHufTable, flags); |
| } |
| |
| /* Build Huffman Tree */ |
| huffLog = HUF_optimalTableLog(huffLog, srcSize, maxSymbolValue, &table->wksps, sizeof(table->wksps), table->CTable, table->count, flags); |
| { size_t const maxBits = HUF_buildCTable_wksp(table->CTable, table->count, |
| maxSymbolValue, huffLog, |
| &table->wksps.buildCTable_wksp, sizeof(table->wksps.buildCTable_wksp)); |
| CHECK_F(maxBits); |
| huffLog = (U32)maxBits; |
| DEBUGLOG(6, "bit distribution completed (%zu symbols)", showCTableBits(table->CTable + 1, maxSymbolValue+1)); |
| } |
| /* 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 */ |
| { CHECK_V_F(hSize, HUF_writeCTable_wksp(op, dstSize, table->CTable, maxSymbolValue, huffLog, |
| &table->wksps.writeCTable_wksp, sizeof(table->wksps.writeCTable_wksp)) ); |
| /* Check if using previous huffman table is beneficial */ |
| if (repeat && *repeat != HUF_repeat_none) { |
| size_t const oldSize = HUF_estimateCompressedSize(oldHufTable, table->count, maxSymbolValue); |
| size_t const newSize = HUF_estimateCompressedSize(table->CTable, table->count, maxSymbolValue); |
| if (oldSize <= hSize + newSize || hSize + 12 >= srcSize) { |
| return HUF_compressCTable_internal(ostart, op, oend, |
| src, srcSize, |
| nbStreams, oldHufTable, flags); |
| } } |
| |
| /* Use the new huffman table */ |
| if (hSize + 12ul >= srcSize) { return 0; } |
| op += hSize; |
| if (repeat) { *repeat = HUF_repeat_none; } |
| if (oldHufTable) |
| ZSTD_memcpy(oldHufTable, table->CTable, sizeof(table->CTable)); /* Save new table */ |
| } |
| return HUF_compressCTable_internal(ostart, op, oend, |
| src, srcSize, |
| nbStreams, table->CTable, flags); |
| } |
| |
| 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 flags) |
| { |
| DEBUGLOG(5, "HUF_compress1X_repeat (srcSize = %zu)", srcSize); |
| return HUF_compress_internal(dst, dstSize, src, srcSize, |
| maxSymbolValue, huffLog, HUF_singleStream, |
| workSpace, wkspSize, hufTable, |
| repeat, flags); |
| } |
| |
| /* 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 flags) |
| { |
| DEBUGLOG(5, "HUF_compress4X_repeat (srcSize = %zu)", srcSize); |
| return HUF_compress_internal(dst, dstSize, src, srcSize, |
| maxSymbolValue, huffLog, HUF_fourStreams, |
| workSpace, wkspSize, |
| hufTable, repeat, flags); |
| } |
