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Diffstat (limited to 'lib/zstd/huf_compress.c')
| -rw-r--r-- | lib/zstd/huf_compress.c | 773 |
1 files changed, 0 insertions, 773 deletions
diff --git a/lib/zstd/huf_compress.c b/lib/zstd/huf_compress.c deleted file mode 100644 index fd32838c185f..000000000000 --- a/lib/zstd/huf_compress.c +++ /dev/null @@ -1,773 +0,0 @@ -/* - * Huffman encoder, part of New Generation Entropy library - * Copyright (C) 2013-2016, Yann Collet. - * - * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php) - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions are - * met: - * - * * Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * * Redistributions in binary form must reproduce the above - * copyright notice, this list of conditions and the following disclaimer - * in the documentation and/or other materials provided with the - * distribution. - * - * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS - * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT - * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR - * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT - * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, - * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT - * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, - * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY - * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT - * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE - * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. - * - * This program is free software; you can redistribute it and/or modify it under - * the terms of the GNU General Public License version 2 as published by the - * Free Software Foundation. This program is dual-licensed; you may select - * either version 2 of the GNU General Public License ("GPL") or BSD license - * ("BSD"). - * - * You can contact the author at : - * - Source repository : https://github.com/Cyan4973/FiniteStateEntropy - */ - -/* ************************************************************** -* Includes -****************************************************************/ -#include "bitstream.h" -#include "fse.h" /* header compression */ -#include "huf.h" -#include <linux/kernel.h> -#include <linux/string.h> /* memcpy, memset */ - -/* ************************************************************** -* Error Management -****************************************************************/ -#define HUF_STATIC_ASSERT(c) \ - { \ - enum { HUF_static_assert = 1 / (int)(!!(c)) }; \ - } /* use only *after* variable declarations */ -#define CHECK_V_F(e, f) \ - size_t const e = f; \ - if (ERR_isError(e)) \ - return f -#define CHECK_F(f) \ - { \ - CHECK_V_F(_var_err__, f); \ - } - -/* ************************************************************** -* Utils -****************************************************************/ -unsigned HUF_optimalTableLog(unsigned maxTableLog, size_t srcSize, unsigned maxSymbolValue) -{ - return FSE_optimalTableLog_internal(maxTableLog, srcSize, maxSymbolValue, 1); -} - -/* ******************************************************* -* HUF : Huffman block compression -*********************************************************/ -/* 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 -size_t HUF_compressWeights_wksp(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; - - U32 maxSymbolValue = HUF_TABLELOG_MAX; - U32 tableLog = MAX_FSE_TABLELOG_FOR_HUFF_HEADER; - - FSE_CTable *CTable; - U32 *count; - S16 *norm; - size_t spaceUsed32 = 0; - - HUF_STATIC_ASSERT(sizeof(FSE_CTable) == sizeof(U32)); - - CTable = (FSE_CTable *)((U32 *)workspace + spaceUsed32); - spaceUsed32 += FSE_CTABLE_SIZE_U32(MAX_FSE_TABLELOG_FOR_HUFF_HEADER, HUF_TABLELOG_MAX); - count = (U32 *)workspace + spaceUsed32; - spaceUsed32 += HUF_TABLELOG_MAX + 1; - norm = (S16 *)((U32 *)workspace + spaceUsed32); - spaceUsed32 += ALIGN(sizeof(S16) * (HUF_TABLELOG_MAX + 1), sizeof(U32)) >> 2; - - if ((spaceUsed32 << 2) > workspaceSize) - return ERROR(tableLog_tooLarge); - workspace = (U32 *)workspace + spaceUsed32; - workspaceSize -= (spaceUsed32 << 2); - - /* init conditions */ - if (wtSize <= 1) - return 0; /* Not compressible */ - - /* Scan input and build symbol stats */ - { - CHECK_V_F(maxCount, FSE_count_simple(count, &maxSymbolValue, weightTable, wtSize)); - 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(norm, tableLog, count, wtSize, maxSymbolValue)); - - /* Write table description header */ - { - CHECK_V_F(hSize, FSE_writeNCount(op, oend - op, norm, maxSymbolValue, tableLog)); - op += hSize; - } - - /* Compress */ - CHECK_F(FSE_buildCTable_wksp(CTable, norm, maxSymbolValue, tableLog, workspace, workspaceSize)); - { - CHECK_V_F(cSize, FSE_compress_usingCTable(op, oend - op, weightTable, wtSize, CTable)); - if (cSize == 0) - return 0; /* not enough space for compressed data */ - op += cSize; - } - - return op - ostart; -} - -struct HUF_CElt_s { - U16 val; - BYTE nbBits; -}; /* typedef'd to HUF_CElt within "huf.h" */ - -/*! HUF_writeCTable_wksp() : - `CTable` : Huffman tree to save, using huf representation. - @return : size of saved CTable */ -size_t HUF_writeCTable_wksp(void *dst, size_t maxDstSize, const HUF_CElt *CTable, U32 maxSymbolValue, U32 huffLog, void *workspace, size_t workspaceSize) -{ - BYTE *op = (BYTE *)dst; - U32 n; - - BYTE *bitsToWeight; - BYTE *huffWeight; - size_t spaceUsed32 = 0; - - bitsToWeight = (BYTE *)((U32 *)workspace + spaceUsed32); - spaceUsed32 += ALIGN(HUF_TABLELOG_MAX + 1, sizeof(U32)) >> 2; - huffWeight = (BYTE *)((U32 *)workspace + spaceUsed32); - spaceUsed32 += ALIGN(HUF_SYMBOLVALUE_MAX, sizeof(U32)) >> 2; - - if ((spaceUsed32 << 2) > workspaceSize) - return ERROR(tableLog_tooLarge); - workspace = (U32 *)workspace + spaceUsed32; - workspaceSize -= (spaceUsed32 << 2); - - /* check conditions */ - if (maxSymbolValue > HUF_SYMBOLVALUE_MAX) - return ERROR(maxSymbolValue_tooLarge); - - /* convert to weight */ - bitsToWeight[0] = 0; - for (n = 1; n < huffLog + 1; n++) - bitsToWeight[n] = (BYTE)(huffLog + 1 - n); - for (n = 0; n < maxSymbolValue; n++) - huffWeight[n] = bitsToWeight[CTable[n].nbBits]; - - /* attempt weights compression by FSE */ - { - CHECK_V_F(hSize, HUF_compressWeights_wksp(op + 1, maxDstSize - 1, huffWeight, maxSymbolValue, workspace, workspaceSize)); - 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)); - 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)((huffWeight[n] << 4) + huffWeight[n + 1]); - return ((maxSymbolValue + 1) / 2) + 1; -} - -size_t HUF_readCTable_wksp(HUF_CElt *CTable, U32 maxSymbolValue, const void *src, size_t srcSize, void *workspace, size_t workspaceSize) -{ - U32 *rankVal; - BYTE *huffWeight; - U32 tableLog = 0; - U32 nbSymbols = 0; - size_t readSize; - size_t spaceUsed32 = 0; - - rankVal = (U32 *)workspace + spaceUsed32; - spaceUsed32 += HUF_TABLELOG_ABSOLUTEMAX + 1; - huffWeight = (BYTE *)((U32 *)workspace + spaceUsed32); - spaceUsed32 += ALIGN(HUF_SYMBOLVALUE_MAX + 1, sizeof(U32)) >> 2; - - if ((spaceUsed32 << 2) > workspaceSize) - return ERROR(tableLog_tooLarge); - workspace = (U32 *)workspace + spaceUsed32; - workspaceSize -= (spaceUsed32 << 2); - - /* get symbol weights */ - readSize = HUF_readStats_wksp(huffWeight, HUF_SYMBOLVALUE_MAX + 1, rankVal, &nbSymbols, &tableLog, src, srcSize, workspace, workspaceSize); - if (ERR_isError(readSize)) - return readSize; - - /* check result */ - if (tableLog > HUF_TABLELOG_MAX) - return ERROR(tableLog_tooLarge); - if (nbSymbols > maxSymbolValue + 1) - return ERROR(maxSymbolValue_tooSmall); - - /* 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]; - CTable[n].nbBits = (BYTE)(tableLog + 1 - w); - } - } - - /* 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]++; - } - /* 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 <= maxSymbolValue; n++) - CTable[n].val = valPerRank[CTable[n].nbBits]++; - } - } - - return readSize; -} - -typedef struct nodeElt_s { - U32 count; - U16 parent; - BYTE byte; - BYTE nbBits; -} nodeElt; - -static U32 HUF_setMaxHeight(nodeElt *huffNode, U32 lastNonNull, U32 maxNbBits) -{ - const U32 largestBits = huffNode[lastNonNull].nbBits; - if (largestBits <= maxNbBits) - return largestBits; /* early exit : no elt > maxNbBits */ - - /* there are several too large elements (at least >= 2) */ - { - int totalCost = 0; - const U32 baseCost = 1 << (largestBits - maxNbBits); - U32 n = lastNonNull; - - while (huffNode[n].nbBits > maxNbBits) { - totalCost += baseCost - (1 << (largestBits - huffNode[n].nbBits)); - huffNode[n].nbBits = (BYTE)maxNbBits; - n--; - } /* n stops at huffNode[n].nbBits <= maxNbBits */ - while (huffNode[n].nbBits == maxNbBits) - n--; /* n end at index of smallest symbol using < maxNbBits */ - - /* renorm totalCost */ - totalCost >>= (largestBits - maxNbBits); /* note : totalCost is necessarily a multiple of baseCost */ - - /* repay normalized cost */ - { - U32 const noSymbol = 0xF0F0F0F0; - U32 rankLast[HUF_TABLELOG_MAX + 2]; - int pos; - - /* Get pos of last (smallest) symbol per rank */ - memset(rankLast, 0xF0, sizeof(rankLast)); - { - U32 currNbBits = maxNbBits; - for (pos = n; pos >= 0; pos--) { - if (huffNode[pos].nbBits >= currNbBits) - continue; - currNbBits = huffNode[pos].nbBits; /* < maxNbBits */ - rankLast[maxNbBits - currNbBits] = pos; - } - } - - while (totalCost > 0) { - U32 nBitsToDecrease = BIT_highbit32(totalCost) + 1; - for (; nBitsToDecrease > 1; nBitsToDecrease--) { - U32 highPos = rankLast[nBitsToDecrease]; - U32 lowPos = rankLast[nBitsToDecrease - 1]; - if (highPos == noSymbol) - continue; - 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 !) */ - /* HUF_MAX_TABLELOG test just to please gcc 5+; but it should not be necessary */ - while ((nBitsToDecrease <= HUF_TABLELOG_MAX) && (rankLast[nBitsToDecrease] == noSymbol)) - nBitsToDecrease++; - totalCost -= 1 << (nBitsToDecrease - 1); - if (rankLast[nBitsToDecrease - 1] == noSymbol) - rankLast[nBitsToDecrease - 1] = rankLast[nBitsToDecrease]; /* this rank is no longer empty */ - huffNode[rankLast[nBitsToDecrease]].nbBits++; - if (rankLast[nBitsToDecrease] == 0) /* special case, reached largest symbol */ - rankLast[nBitsToDecrease] = noSymbol; - else { - rankLast[nBitsToDecrease]--; - if (huffNode[rankLast[nBitsToDecrease]].nbBits != maxNbBits - nBitsToDecrease) - rankLast[nBitsToDecrease] = noSymbol; /* this rank is now empty */ - } - } /* while (totalCost > 0) */ - - while (totalCost < 0) { /* Sometimes, cost correction overshoot */ - if (rankLast[1] == noSymbol) { /* special case : no rank 1 symbol (using maxNbBits-1); let's create one from largest rank 0 - (using maxNbBits) */ - while (huffNode[n].nbBits == maxNbBits) - n--; - huffNode[n + 1].nbBits--; - rankLast[1] = n + 1; - totalCost++; - continue; - } - huffNode[rankLast[1] + 1].nbBits--; - rankLast[1]++; - totalCost++; - } - } - } /* there are several too large elements (at least >= 2) */ - - return maxNbBits; -} - -typedef struct { - U32 base; - U32 curr; -} rankPos; - -static void HUF_sort(nodeElt *huffNode, const U32 *count, U32 maxSymbolValue) -{ - rankPos rank[32]; - U32 n; - - memset(rank, 0, sizeof(rank)); - for (n = 0; n <= maxSymbolValue; n++) { - U32 r = BIT_highbit32(count[n] + 1); - rank[r].base++; - } - for (n = 30; n > 0; n--) - rank[n - 1].base += rank[n].base; - for (n = 0; n < 32; n++) - rank[n].curr = rank[n].base; - for (n = 0; n <= maxSymbolValue; n++) { - U32 const c = count[n]; - U32 const r = BIT_highbit32(c + 1) + 1; - U32 pos = rank[r].curr++; - while ((pos > rank[r].base) && (c > huffNode[pos - 1].count)) - huffNode[pos] = huffNode[pos - 1], pos--; - huffNode[pos].count = c; - huffNode[pos].byte = (BYTE)n; - } -} - -/** 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 a table of 1024 unsigned. - */ -#define STARTNODE (HUF_SYMBOLVALUE_MAX + 1) -typedef nodeElt huffNodeTable[2 * HUF_SYMBOLVALUE_MAX + 1 + 1]; -size_t HUF_buildCTable_wksp(HUF_CElt *tree, const U32 *count, U32 maxSymbolValue, U32 maxNbBits, void *workSpace, size_t wkspSize) -{ - nodeElt *const huffNode0 = (nodeElt *)workSpace; - nodeElt *const huffNode = huffNode0 + 1; - U32 n, nonNullRank; - int lowS, lowN; - U16 nodeNb = STARTNODE; - U32 nodeRoot; - - /* safety checks */ - if (wkspSize < sizeof(huffNodeTable)) - return ERROR(GENERIC); /* workSpace is not large enough */ - if (maxNbBits == 0) - maxNbBits = HUF_TABLELOG_DEFAULT; - if (maxSymbolValue > HUF_SYMBOLVALUE_MAX) - return ERROR(GENERIC); - memset(huffNode0, 0, sizeof(huffNodeTable)); - - /* sort, decreasing order */ - HUF_sort(huffNode, count, maxSymbolValue); - - /* init for parents */ - nonNullRank = 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 = 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) { - U32 n1 = (huffNode[lowS].count < huffNode[lowN].count) ? lowS-- : lowN++; - U32 n2 = (huffNode[lowS].count < huffNode[lowN].count) ? lowS-- : lowN++; - huffNode[nodeNb].count = huffNode[n1].count + huffNode[n2].count; - huffNode[n1].parent = huffNode[n2].parent = 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; - - /* enforce maxTableLog */ - maxNbBits = HUF_setMaxHeight(huffNode, nonNullRank, maxNbBits); - - /* fill result into tree (val, nbBits) */ - { - U16 nbPerRank[HUF_TABLELOG_MAX + 1] = {0}; - U16 valPerRank[HUF_TABLELOG_MAX + 1] = {0}; - if (maxNbBits > HUF_TABLELOG_MAX) - return ERROR(GENERIC); /* check fit into table */ - for (n = 0; n <= nonNullRank; n++) - nbPerRank[huffNode[n].nbBits]++; - /* determine stating value per rank */ - { - U16 min = 0; - for (n = maxNbBits; n > 0; n--) { - valPerRank[n] = min; /* get starting value within each rank */ - min += nbPerRank[n]; - min >>= 1; - } - } - for (n = 0; n <= maxSymbolValue; n++) - tree[huffNode[n].byte].nbBits = huffNode[n].nbBits; /* push nbBits per symbol, symbol order */ - for (n = 0; n <= maxSymbolValue; n++) - tree[n].val = valPerRank[tree[n].nbBits]++; /* assign value within rank, symbol order */ - } - - return maxNbBits; -} - -static size_t HUF_estimateCompressedSize(HUF_CElt *CTable, const unsigned *count, unsigned maxSymbolValue) -{ - size_t nbBits = 0; - int s; - for (s = 0; s <= (int)maxSymbolValue; ++s) { - nbBits += CTable[s].nbBits * count[s]; - } - return nbBits >> 3; -} - -static int HUF_validateCTable(const HUF_CElt *CTable, const unsigned *count, unsigned maxSymbolValue) -{ - int bad = 0; - int s; - for (s = 0; s <= (int)maxSymbolValue; ++s) { - bad |= (count[s] != 0) & (CTable[s].nbBits == 0); - } - return !bad; -} - -static void HUF_encodeSymbol(BIT_CStream_t *bitCPtr, U32 symbol, const HUF_CElt *CTable) -{ - BIT_addBitsFast(bitCPtr, CTable[symbol].val, CTable[symbol].nbBits); -} - -size_t HUF_compressBound(size_t size) { return HUF_COMPRESSBOUND(size); } - -#define HUF_FLUSHBITS(s) BIT_flushBits(s) - -#define HUF_FLUSHBITS_1(stream) \ - if (sizeof((stream)->bitContainer) * 8 < HUF_TABLELOG_MAX * 2 + 7) \ - HUF_FLUSHBITS(stream) - -#define HUF_FLUSHBITS_2(stream) \ - if (sizeof((stream)->bitContainer) * 8 < HUF_TABLELOG_MAX * 4 + 7) \ - HUF_FLUSHBITS(stream) - -size_t HUF_compress1X_usingCTable(void *dst, size_t dstSize, const void *src, size_t srcSize, const HUF_CElt *CTable) -{ - 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; - - /* init */ - if (dstSize < 8) - return 0; /* not enough space to compress */ - { - size_t const initErr = BIT_initCStream(&bitC, op, 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); - fallthrough; - case 2: HUF_encodeSymbol(&bitC, ip[n + 1], CTable); HUF_FLUSHBITS_1(&bitC); - fallthrough; - case 1: HUF_encodeSymbol(&bitC, ip[n + 0], CTable); HUF_FLUSHBITS(&bitC); - fallthrough; - case 0: - default:; - } - - 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); - } - - return BIT_closeCStream(&bitC); -} - -size_t HUF_compress4X_usingCTable(void *dst, size_t dstSize, const void *src, size_t srcSize, const HUF_CElt *CTable) -{ - 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 */ - - { - CHECK_V_F(cSize, HUF_compress1X_usingCTable(op, oend - op, ip, segmentSize, CTable)); - if (cSize == 0) - return 0; - ZSTD_writeLE16(ostart, (U16)cSize); - op += cSize; - } - - ip += segmentSize; - { - CHECK_V_F(cSize, HUF_compress1X_usingCTable(op, oend - op, ip, segmentSize, CTable)); - if (cSize == 0) - return 0; - ZSTD_writeLE16(ostart + 2, (U16)cSize); - op += cSize; - } - - ip += segmentSize; - { - CHECK_V_F(cSize, HUF_compress1X_usingCTable(op, oend - op, ip, segmentSize, CTable)); - if (cSize == 0) - return 0; - ZSTD_writeLE16(ostart + 4, (U16)cSize); - op += cSize; - } - - ip += segmentSize; - { - CHECK_V_F(cSize, HUF_compress1X_usingCTable(op, oend - op, ip, iend - ip, CTable)); - if (cSize == 0) - return 0; - op += cSize; - } - - return op - ostart; -} - -static size_t HUF_compressCTable_internal(BYTE *const ostart, BYTE *op, BYTE *const oend, const void *src, size_t srcSize, unsigned singleStream, - const HUF_CElt *CTable) -{ - size_t const cSize = - singleStream ? HUF_compress1X_usingCTable(op, oend - op, src, srcSize, CTable) : HUF_compress4X_usingCTable(op, oend - op, src, srcSize, CTable); - if (HUF_isError(cSize)) { - return cSize; - } - if (cSize == 0) { - return 0; - } /* uncompressible */ - op += cSize; - /* check compressibility */ - if ((size_t)(op - ostart) >= srcSize - 1) { - return 0; - } - return op - ostart; -} - -/* `workSpace` must a table of at least 1024 unsigned */ -static size_t HUF_compress_internal(void *dst, size_t dstSize, const void *src, size_t srcSize, unsigned maxSymbolValue, unsigned huffLog, - unsigned singleStream, void *workSpace, size_t wkspSize, HUF_CElt *oldHufTable, HUF_repeat *repeat, int preferRepeat) -{ - BYTE *const ostart = (BYTE *)dst; - BYTE *const oend = ostart + dstSize; - BYTE *op = ostart; - - U32 *count; - size_t const countSize = sizeof(U32) * (HUF_SYMBOLVALUE_MAX + 1); - HUF_CElt *CTable; - size_t const CTableSize = sizeof(HUF_CElt) * (HUF_SYMBOLVALUE_MAX + 1); - - /* checks & inits */ - if (wkspSize < sizeof(huffNodeTable) + countSize + CTableSize) - return ERROR(GENERIC); - if (!srcSize) - return 0; /* Uncompressed (note : 1 means rle, so first byte must be correct) */ - if (!dstSize) - return 0; /* cannot fit within dst budget */ - if (srcSize > HUF_BLOCKSIZE_MAX) - return ERROR(srcSize_wrong); /* curr block size limit */ - if (huffLog > HUF_TABLELOG_MAX) - return ERROR(tableLog_tooLarge); - if (!maxSymbolValue) - maxSymbolValue = HUF_SYMBOLVALUE_MAX; - if (!huffLog) - huffLog = HUF_TABLELOG_DEFAULT; - - count = (U32 *)workSpace; - workSpace = (BYTE *)workSpace + countSize; - wkspSize -= countSize; - CTable = (HUF_CElt *)workSpace; - workSpace = (BYTE *)workSpace + CTableSize; - wkspSize -= CTableSize; - - /* Heuristic : If we don't need to check the validity of the old table use the old table for small inputs */ - if (preferRepeat && repeat && *repeat == HUF_repeat_valid) { - return HUF_compressCTable_internal(ostart, op, oend, src, srcSize, singleStream, oldHufTable); - } - - /* Scan input and build symbol stats */ - { - CHECK_V_F(largest, FSE_count_wksp(count, &maxSymbolValue, (const BYTE *)src, srcSize, (U32 *)workSpace)); - if (largest == srcSize) { - *ostart = ((const BYTE *)src)[0]; - return 1; - } /* single symbol, rle */ - if (largest <= (srcSize >> 7) + 1) - return 0; /* Fast heuristic : not compressible enough */ - } - - /* Check validity of previous table */ - if (repeat && *repeat == HUF_repeat_check && !HUF_validateCTable(oldHufTable, count, maxSymbolValue)) { - *repeat = HUF_repeat_none; - } - /* Heuristic : use existing table for small inputs */ - if (preferRepeat && repeat && *repeat != HUF_repeat_none) { - return HUF_compressCTable_internal(ostart, op, oend, src, srcSize, singleStream, oldHufTable); - } - - /* Build Huffman Tree */ - huffLog = HUF_optimalTableLog(huffLog, srcSize, maxSymbolValue); - { - CHECK_V_F(maxBits, HUF_buildCTable_wksp(CTable, count, maxSymbolValue, huffLog, workSpace, wkspSize)); - huffLog = (U32)maxBits; - /* Zero the unused symbols so we can check it for validity */ - memset(CTable + maxSymbolValue + 1, 0, CTableSize - (maxSymbolValue + 1) * sizeof(HUF_CElt)); - } - - /* Write table description header */ - { - CHECK_V_F(hSize, HUF_writeCTable_wksp(op, dstSize, CTable, maxSymbolValue, huffLog, workSpace, wkspSize)); - /* Check if using the previous table will be beneficial */ - if (repeat && *repeat != HUF_repeat_none) { - size_t const oldSize = HUF_estimateCompressedSize(oldHufTable, count, maxSymbolValue); - size_t const newSize = HUF_estimateCompressedSize(CTable, count, maxSymbolValue); - if (oldSize <= hSize + newSize || hSize + 12 >= srcSize) { - return HUF_compressCTable_internal(ostart, op, oend, src, srcSize, singleStream, oldHufTable); - } - } - /* Use the new table */ - if (hSize + 12ul >= srcSize) { - return 0; - } - op += hSize; - if (repeat) { - *repeat = HUF_repeat_none; - } - if (oldHufTable) { - memcpy(oldHufTable, CTable, CTableSize); - } /* Save the new table */ - } - return HUF_compressCTable_internal(ostart, op, oend, src, srcSize, singleStream, CTable); -} - -size_t HUF_compress1X_wksp(void *dst, size_t dstSize, const void *src, size_t srcSize, unsigned maxSymbolValue, unsigned huffLog, void *workSpace, - size_t wkspSize) -{ - return HUF_compress_internal(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, 1 /* single stream */, workSpace, wkspSize, NULL, NULL, 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) -{ - return HUF_compress_internal(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, 1 /* single stream */, workSpace, wkspSize, hufTable, repeat, - preferRepeat); -} - -size_t HUF_compress4X_wksp(void *dst, size_t dstSize, const void *src, size_t srcSize, unsigned maxSymbolValue, unsigned huffLog, void *workSpace, - size_t wkspSize) -{ - return HUF_compress_internal(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, 0 /* 4 streams */, workSpace, wkspSize, NULL, NULL, 0); -} - -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) -{ - return HUF_compress_internal(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, 0 /* 4 streams */, workSpace, wkspSize, hufTable, repeat, - preferRepeat); -} |