276 lines
9.5 KiB
C
276 lines
9.5 KiB
C
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/* ******************************************************************
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* FSE : Finite State Entropy decoder
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* Copyright (c) 2013-2020, Yann Collet, Facebook, Inc.
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*
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* You can contact the author at :
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* - FSE source repository : https://github.com/Cyan4973/FiniteStateEntropy
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* - Public forum : https://groups.google.com/forum/#!forum/lz4c
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*
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* This source code is licensed under both the BSD-style license (found in the
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* LICENSE file in the root directory of this source tree) and the GPLv2 (found
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* in the COPYING file in the root directory of this source tree).
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* You may select, at your option, one of the above-listed licenses.
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****************************************************************** */
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/* **************************************************************
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* Includes
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****************************************************************/
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#include <stdlib.h> /* malloc, free, qsort */
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#include <string.h> /* memcpy, memset */
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#include "bitstream.h"
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#include "compiler.h"
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#define FSE_STATIC_LINKING_ONLY
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#include "fse.h"
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#include "error_private.h"
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/* **************************************************************
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* Error Management
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****************************************************************/
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#define FSE_isError ERR_isError
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#define FSE_STATIC_ASSERT(c) DEBUG_STATIC_ASSERT(c) /* use only *after* variable declarations */
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/* **************************************************************
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* Templates
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****************************************************************/
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/*
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designed to be included
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for type-specific functions (template emulation in C)
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Objective is to write these functions only once, for improved maintenance
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*/
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/* safety checks */
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#ifndef FSE_FUNCTION_EXTENSION
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# error "FSE_FUNCTION_EXTENSION must be defined"
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#endif
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#ifndef FSE_FUNCTION_TYPE
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# error "FSE_FUNCTION_TYPE must be defined"
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#endif
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/* Function names */
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#define FSE_CAT(X,Y) X##Y
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#define FSE_FUNCTION_NAME(X,Y) FSE_CAT(X,Y)
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#define FSE_TYPE_NAME(X,Y) FSE_CAT(X,Y)
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/* Function templates */
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size_t FSE_buildDTable(FSE_DTable* dt, const short* normalizedCounter, unsigned maxSymbolValue, unsigned tableLog)
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{
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void* const tdPtr = dt+1; /* because *dt is unsigned, 32-bits aligned on 32-bits */
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FSE_DECODE_TYPE* const tableDecode = (FSE_DECODE_TYPE*) (tdPtr);
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U16 symbolNext[FSE_MAX_SYMBOL_VALUE+1];
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U32 const maxSV1 = maxSymbolValue + 1;
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U32 const tableSize = 1 << tableLog;
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U32 highThreshold = tableSize-1;
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/* Sanity Checks */
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if (maxSymbolValue > FSE_MAX_SYMBOL_VALUE) return ERROR(maxSymbolValue_tooLarge);
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if (tableLog > FSE_MAX_TABLELOG) return ERROR(tableLog_tooLarge);
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/* Init, lay down lowprob symbols */
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{ FSE_DTableHeader DTableH;
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DTableH.tableLog = (U16)tableLog;
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DTableH.fastMode = 1;
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{ S16 const largeLimit= (S16)(1 << (tableLog-1));
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U32 s;
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for (s=0; s<maxSV1; s++) {
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if (normalizedCounter[s]==-1) {
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tableDecode[highThreshold--].symbol = (FSE_FUNCTION_TYPE)s;
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symbolNext[s] = 1;
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} else {
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if (normalizedCounter[s] >= largeLimit) DTableH.fastMode=0;
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symbolNext[s] = normalizedCounter[s];
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} } }
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memcpy(dt, &DTableH, sizeof(DTableH));
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}
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/* Spread symbols */
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{ U32 const tableMask = tableSize-1;
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U32 const step = FSE_TABLESTEP(tableSize);
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U32 s, position = 0;
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for (s=0; s<maxSV1; s++) {
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int i;
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for (i=0; i<normalizedCounter[s]; i++) {
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tableDecode[position].symbol = (FSE_FUNCTION_TYPE)s;
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position = (position + step) & tableMask;
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while (position > highThreshold) position = (position + step) & tableMask; /* lowprob area */
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} }
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if (position!=0) return ERROR(GENERIC); /* position must reach all cells once, otherwise normalizedCounter is incorrect */
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}
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/* Build Decoding table */
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{ U32 u;
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for (u=0; u<tableSize; u++) {
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FSE_FUNCTION_TYPE const symbol = (FSE_FUNCTION_TYPE)(tableDecode[u].symbol);
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U32 const nextState = symbolNext[symbol]++;
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tableDecode[u].nbBits = (BYTE) (tableLog - BIT_highbit32(nextState) );
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tableDecode[u].newState = (U16) ( (nextState << tableDecode[u].nbBits) - tableSize);
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} }
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return 0;
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}
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#ifndef FSE_COMMONDEFS_ONLY
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/*-*******************************************************
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* Decompression (Byte symbols)
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*********************************************************/
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size_t FSE_buildDTable_rle (FSE_DTable* dt, BYTE symbolValue)
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{
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void* ptr = dt;
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FSE_DTableHeader* const DTableH = (FSE_DTableHeader*)ptr;
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void* dPtr = dt + 1;
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FSE_decode_t* const cell = (FSE_decode_t*)dPtr;
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DTableH->tableLog = 0;
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DTableH->fastMode = 0;
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cell->newState = 0;
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cell->symbol = symbolValue;
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cell->nbBits = 0;
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return 0;
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}
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size_t FSE_buildDTable_raw (FSE_DTable* dt, unsigned nbBits)
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{
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void* ptr = dt;
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FSE_DTableHeader* const DTableH = (FSE_DTableHeader*)ptr;
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void* dPtr = dt + 1;
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FSE_decode_t* const dinfo = (FSE_decode_t*)dPtr;
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const unsigned tableSize = 1 << nbBits;
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const unsigned tableMask = tableSize - 1;
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const unsigned maxSV1 = tableMask+1;
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unsigned s;
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/* Sanity checks */
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if (nbBits < 1) return ERROR(GENERIC); /* min size */
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/* Build Decoding Table */
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DTableH->tableLog = (U16)nbBits;
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DTableH->fastMode = 1;
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for (s=0; s<maxSV1; s++) {
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dinfo[s].newState = 0;
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dinfo[s].symbol = (BYTE)s;
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dinfo[s].nbBits = (BYTE)nbBits;
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}
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return 0;
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}
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FORCE_INLINE_TEMPLATE size_t FSE_decompress_usingDTable_generic(
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void* dst, size_t maxDstSize,
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const void* cSrc, size_t cSrcSize,
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const FSE_DTable* dt, const unsigned fast)
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{
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BYTE* const ostart = (BYTE*) dst;
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BYTE* op = ostart;
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BYTE* const omax = op + maxDstSize;
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BYTE* const olimit = omax-3;
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BIT_DStream_t bitD;
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FSE_DState_t state1;
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FSE_DState_t state2;
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/* Init */
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CHECK_F(BIT_initDStream(&bitD, cSrc, cSrcSize));
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FSE_initDState(&state1, &bitD, dt);
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FSE_initDState(&state2, &bitD, dt);
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#define FSE_GETSYMBOL(statePtr) fast ? FSE_decodeSymbolFast(statePtr, &bitD) : FSE_decodeSymbol(statePtr, &bitD)
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/* 4 symbols per loop */
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for ( ; (BIT_reloadDStream(&bitD)==BIT_DStream_unfinished) & (op<olimit) ; op+=4) {
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op[0] = FSE_GETSYMBOL(&state1);
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if (FSE_MAX_TABLELOG*2+7 > sizeof(bitD.bitContainer)*8) /* This test must be static */
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BIT_reloadDStream(&bitD);
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op[1] = FSE_GETSYMBOL(&state2);
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if (FSE_MAX_TABLELOG*4+7 > sizeof(bitD.bitContainer)*8) /* This test must be static */
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{ if (BIT_reloadDStream(&bitD) > BIT_DStream_unfinished) { op+=2; break; } }
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op[2] = FSE_GETSYMBOL(&state1);
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if (FSE_MAX_TABLELOG*2+7 > sizeof(bitD.bitContainer)*8) /* This test must be static */
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BIT_reloadDStream(&bitD);
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op[3] = FSE_GETSYMBOL(&state2);
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}
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/* tail */
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/* note : BIT_reloadDStream(&bitD) >= FSE_DStream_partiallyFilled; Ends at exactly BIT_DStream_completed */
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while (1) {
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if (op>(omax-2)) return ERROR(dstSize_tooSmall);
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*op++ = FSE_GETSYMBOL(&state1);
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if (BIT_reloadDStream(&bitD)==BIT_DStream_overflow) {
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*op++ = FSE_GETSYMBOL(&state2);
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break;
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}
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if (op>(omax-2)) return ERROR(dstSize_tooSmall);
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*op++ = FSE_GETSYMBOL(&state2);
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if (BIT_reloadDStream(&bitD)==BIT_DStream_overflow) {
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*op++ = FSE_GETSYMBOL(&state1);
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break;
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} }
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return op-ostart;
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}
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size_t FSE_decompress_usingDTable(void* dst, size_t originalSize,
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const void* cSrc, size_t cSrcSize,
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const FSE_DTable* dt)
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{
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const void* ptr = dt;
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const FSE_DTableHeader* DTableH = (const FSE_DTableHeader*)ptr;
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const U32 fastMode = DTableH->fastMode;
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/* select fast mode (static) */
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if (fastMode) return FSE_decompress_usingDTable_generic(dst, originalSize, cSrc, cSrcSize, dt, 1);
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return FSE_decompress_usingDTable_generic(dst, originalSize, cSrc, cSrcSize, dt, 0);
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}
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size_t FSE_decompress_wksp(void* dst, size_t dstCapacity, const void* cSrc, size_t cSrcSize, FSE_DTable* workSpace, unsigned maxLog)
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{
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const BYTE* const istart = (const BYTE*)cSrc;
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const BYTE* ip = istart;
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short counting[FSE_MAX_SYMBOL_VALUE+1];
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unsigned tableLog;
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unsigned maxSymbolValue = FSE_MAX_SYMBOL_VALUE;
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/* normal FSE decoding mode */
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size_t const NCountLength = FSE_readNCount (counting, &maxSymbolValue, &tableLog, istart, cSrcSize);
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if (FSE_isError(NCountLength)) return NCountLength;
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/* if (NCountLength >= cSrcSize) return ERROR(srcSize_wrong); */ /* too small input size; supposed to be already checked in NCountLength, only remaining case : NCountLength==cSrcSize */
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if (tableLog > maxLog) return ERROR(tableLog_tooLarge);
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ip += NCountLength;
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cSrcSize -= NCountLength;
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CHECK_F( FSE_buildDTable (workSpace, counting, maxSymbolValue, tableLog) );
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return FSE_decompress_usingDTable (dst, dstCapacity, ip, cSrcSize, workSpace); /* always return, even if it is an error code */
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}
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typedef FSE_DTable DTable_max_t[FSE_DTABLE_SIZE_U32(FSE_MAX_TABLELOG)];
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size_t FSE_decompress(void* dst, size_t dstCapacity, const void* cSrc, size_t cSrcSize)
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{
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DTable_max_t dt; /* Static analyzer seems unable to understand this table will be properly initialized later */
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return FSE_decompress_wksp(dst, dstCapacity, cSrc, cSrcSize, dt, FSE_MAX_TABLELOG);
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}
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#endif /* FSE_COMMONDEFS_ONLY */
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