lib/zstd/fse_decompress.c - third_party/kernel - Git at Google

 /*
  * FSE : Finite State Entropy decoder
  * Copyright (C) 2013-2015, 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
  */

 /* **************************************************************
 *  Compiler specifics
 ****************************************************************/
 #define FORCE_INLINE static __always_inline

 /* **************************************************************
 *  Includes
 ****************************************************************/
 #include "bitstream.h"
 #include "fse.h"
 #include "zstd_internal.h"
 #include <linux/compiler.h>
 #include <linux/kernel.h>
 #include <linux/string.h> /* memcpy, memset */

 /* **************************************************************
 *  Error Management
 ****************************************************************/
 #define FSE_isError ERR_isError
 #define FSE_STATIC_ASSERT(c)                                   \
 	{                                                      \
 		enum { FSE_static_assert = 1 / (int)(!!(c)) }; \
 	} /* use only *after* variable declarations */

 /* **************************************************************
 *  Templates
 ****************************************************************/
 /*
   designed to be included
   for type-specific functions (template emulation in C)
   Objective is to write these functions only once, for improved maintenance
 */

 /* safety checks */
 #ifndef FSE_FUNCTION_EXTENSION
 #error "FSE_FUNCTION_EXTENSION must be defined"
 #endif
 #ifndef FSE_FUNCTION_TYPE
 #error "FSE_FUNCTION_TYPE must be defined"
 #endif

 /* Function names */
 #define FSE_CAT(X, Y) X##Y
 #define FSE_FUNCTION_NAME(X, Y) FSE_CAT(X, Y)
 #define FSE_TYPE_NAME(X, Y) FSE_CAT(X, Y)

 /* Function templates */

 size_t FSE_buildDTable_wksp(FSE_DTable *dt, const short *normalizedCounter, unsigned maxSymbolValue, unsigned tableLog, void *workspace, size_t workspaceSize)
 {
 	void *const tdPtr = dt + 1; /* because *dt is unsigned, 32-bits aligned on 32-bits */
 	FSE_DECODE_TYPE *const tableDecode = (FSE_DECODE_TYPE *)(tdPtr);
 	U16 *symbolNext = (U16 *)workspace;

 	U32 const maxSV1 = maxSymbolValue + 1;
 	U32 const tableSize = 1 << tableLog;
 	U32 highThreshold = tableSize - 1;

 	/* Sanity Checks */
 	if (workspaceSize < sizeof(U16) * (FSE_MAX_SYMBOL_VALUE + 1))
 		return ERROR(tableLog_tooLarge);
 	if (maxSymbolValue > FSE_MAX_SYMBOL_VALUE)
 		return ERROR(maxSymbolValue_tooLarge);
 	if (tableLog > FSE_MAX_TABLELOG)
 		return ERROR(tableLog_tooLarge);

 	/* Init, lay down lowprob symbols */
 	{
 		FSE_DTableHeader DTableH;
 		DTableH.tableLog = (U16)tableLog;
 		DTableH.fastMode = 1;
 		{
 			S16 const largeLimit = (S16)(1 << (tableLog - 1));
 			U32 s;
 			for (s = 0; s < maxSV1; s++) {
 				if (normalizedCounter[s] == -1) {
 					tableDecode[highThreshold--].symbol = (FSE_FUNCTION_TYPE)s;
 					symbolNext[s] = 1;
 				} else {
 					if (normalizedCounter[s] >= largeLimit)
 						DTableH.fastMode = 0;
 					symbolNext[s] = normalizedCounter[s];
 				}
 			}
 		}
 		memcpy(dt, &DTableH, sizeof(DTableH));
 	}

 	/* Spread symbols */
 	{
 		U32 const tableMask = tableSize - 1;
 		U32 const step = FSE_TABLESTEP(tableSize);
 		U32 s, position = 0;
 		for (s = 0; s < maxSV1; s++) {
 			int i;
 			for (i = 0; i < normalizedCounter[s]; i++) {
 				tableDecode[position].symbol = (FSE_FUNCTION_TYPE)s;
 				position = (position + step) & tableMask;
 				while (position > highThreshold)
 					position = (position + step) & tableMask; /* lowprob area */
 			}
 		}
 		if (position != 0)
 			return ERROR(GENERIC); /* position must reach all cells once, otherwise normalizedCounter is incorrect */
 	}

 	/* Build Decoding table */
 	{
 		U32 u;
 		for (u = 0; u < tableSize; u++) {
 			FSE_FUNCTION_TYPE const symbol = (FSE_FUNCTION_TYPE)(tableDecode[u].symbol);
 			U16 nextState = symbolNext[symbol]++;
 			tableDecode[u].nbBits = (BYTE)(tableLog - BIT_highbit32((U32)nextState));
 			tableDecode[u].newState = (U16)((nextState << tableDecode[u].nbBits) - tableSize);
 		}
 	}

 	return 0;
 }

 /*-*******************************************************
 *  Decompression (Byte symbols)
 *********************************************************/
 size_t FSE_buildDTable_rle(FSE_DTable *dt, BYTE symbolValue)
 {
 	void *ptr = dt;
 	FSE_DTableHeader *const DTableH = (FSE_DTableHeader *)ptr;
 	void *dPtr = dt + 1;
 	FSE_decode_t *const cell = (FSE_decode_t *)dPtr;

 	DTableH->tableLog = 0;
 	DTableH->fastMode = 0;

 	cell->newState = 0;
 	cell->symbol = symbolValue;
 	cell->nbBits = 0;

 	return 0;
 }

 size_t FSE_buildDTable_raw(FSE_DTable *dt, unsigned nbBits)
 {
 	void *ptr = dt;
 	FSE_DTableHeader *const DTableH = (FSE_DTableHeader *)ptr;
 	void *dPtr = dt + 1;
 	FSE_decode_t *const dinfo = (FSE_decode_t *)dPtr;
 	const unsigned tableSize = 1 << nbBits;
 	const unsigned tableMask = tableSize - 1;
 	const unsigned maxSV1 = tableMask + 1;
 	unsigned s;

 	/* Sanity checks */
 	if (nbBits < 1)
 		return ERROR(GENERIC); /* min size */

 	/* Build Decoding Table */
 	DTableH->tableLog = (U16)nbBits;
 	DTableH->fastMode = 1;
 	for (s = 0; s < maxSV1; s++) {
 		dinfo[s].newState = 0;
 		dinfo[s].symbol = (BYTE)s;
 		dinfo[s].nbBits = (BYTE)nbBits;
 	}

 	return 0;
 }

 FORCE_INLINE size_t FSE_decompress_usingDTable_generic(void *dst, size_t maxDstSize, const void *cSrc, size_t cSrcSize, const FSE_DTable *dt,
 						       const unsigned fast)
 {
 	BYTE *const ostart = (BYTE *)dst;
 	BYTE *op = ostart;
 	BYTE *const omax = op + maxDstSize;
 	BYTE *const olimit = omax - 3;

 	BIT_DStream_t bitD;
 	FSE_DState_t state1;
 	FSE_DState_t state2;

 	/* Init */
 	CHECK_F(BIT_initDStream(&bitD, cSrc, cSrcSize));

 	FSE_initDState(&state1, &bitD, dt);
 	FSE_initDState(&state2, &bitD, dt);

 #define FSE_GETSYMBOL(statePtr) fast ? FSE_decodeSymbolFast(statePtr, &bitD) : FSE_decodeSymbol(statePtr, &bitD)

 	/* 4 symbols per loop */
 	for (; (BIT_reloadDStream(&bitD) == BIT_DStream_unfinished) & (op < olimit); op += 4) {
 		op[0] = FSE_GETSYMBOL(&state1);

 		if (FSE_MAX_TABLELOG * 2 + 7 > sizeof(bitD.bitContainer) * 8) /* This test must be static */
 			BIT_reloadDStream(&bitD);

 		op[1] = FSE_GETSYMBOL(&state2);

 		if (FSE_MAX_TABLELOG * 4 + 7 > sizeof(bitD.bitContainer) * 8) /* This test must be static */
 		{
 			if (BIT_reloadDStream(&bitD) > BIT_DStream_unfinished) {
 				op += 2;
 				break;
 			}
 		}

 		op[2] = FSE_GETSYMBOL(&state1);

 		if (FSE_MAX_TABLELOG * 2 + 7 > sizeof(bitD.bitContainer) * 8) /* This test must be static */
 			BIT_reloadDStream(&bitD);

 		op[3] = FSE_GETSYMBOL(&state2);
 	}

 	/* tail */
 	/* note : BIT_reloadDStream(&bitD) >= FSE_DStream_partiallyFilled; Ends at exactly BIT_DStream_completed */
 	while (1) {
 		if (op > (omax - 2))
 			return ERROR(dstSize_tooSmall);
 		*op++ = FSE_GETSYMBOL(&state1);
 		if (BIT_reloadDStream(&bitD) == BIT_DStream_overflow) {
 			*op++ = FSE_GETSYMBOL(&state2);
 			break;
 		}

 		if (op > (omax - 2))
 			return ERROR(dstSize_tooSmall);
 		*op++ = FSE_GETSYMBOL(&state2);
 		if (BIT_reloadDStream(&bitD) == BIT_DStream_overflow) {
 			*op++ = FSE_GETSYMBOL(&state1);
 			break;
 		}
 	}

 	return op - ostart;
 }

 size_t FSE_decompress_usingDTable(void *dst, size_t originalSize, const void *cSrc, size_t cSrcSize, const FSE_DTable *dt)
 {
 	const void *ptr = dt;
 	const FSE_DTableHeader *DTableH = (const FSE_DTableHeader *)ptr;
 	const U32 fastMode = DTableH->fastMode;

 	/* select fast mode (static) */
 	if (fastMode)
 		return FSE_decompress_usingDTable_generic(dst, originalSize, cSrc, cSrcSize, dt, 1);
 	return FSE_decompress_usingDTable_generic(dst, originalSize, cSrc, cSrcSize, dt, 0);
 }

 size_t FSE_decompress_wksp(void *dst, size_t dstCapacity, const void *cSrc, size_t cSrcSize, unsigned maxLog, void *workspace, size_t workspaceSize)
 {
 	const BYTE *const istart = (const BYTE *)cSrc;
 	const BYTE *ip = istart;
 	unsigned tableLog;
 	unsigned maxSymbolValue = FSE_MAX_SYMBOL_VALUE;
 	size_t NCountLength;

 	FSE_DTable *dt;
 	short *counting;
 	size_t spaceUsed32 = 0;

 	FSE_STATIC_ASSERT(sizeof(FSE_DTable) == sizeof(U32));

 	dt = (FSE_DTable *)((U32 *)workspace + spaceUsed32);
 	spaceUsed32 += FSE_DTABLE_SIZE_U32(maxLog);
 	counting = (short *)((U32 *)workspace + spaceUsed32);
 	spaceUsed32 += ALIGN(sizeof(short) * (FSE_MAX_SYMBOL_VALUE + 1), sizeof(U32)) >> 2;

 	if ((spaceUsed32 << 2) > workspaceSize)
 		return ERROR(tableLog_tooLarge);
 	workspace = (U32 *)workspace + spaceUsed32;
 	workspaceSize -= (spaceUsed32 << 2);

 	/* normal FSE decoding mode */
 	NCountLength = FSE_readNCount(counting, &maxSymbolValue, &tableLog, istart, cSrcSize);
 	if (FSE_isError(NCountLength))
 		return NCountLength;
 	// if (NCountLength >= cSrcSize) return ERROR(srcSize_wrong);   /* too small input size; supposed to be already checked in NCountLength, only remaining
 	// case : NCountLength==cSrcSize */
 	if (tableLog > maxLog)
 		return ERROR(tableLog_tooLarge);
 	ip += NCountLength;
 	cSrcSize -= NCountLength;

 	CHECK_F(FSE_buildDTable_wksp(dt, counting, maxSymbolValue, tableLog, workspace, workspaceSize));

 	return FSE_decompress_usingDTable(dst, dstCapacity, ip, cSrcSize, dt); /* always return, even if it is an error code */
 }
	/*
	* FSE : Finite State Entropy decoder
	* Copyright (C) 2013-2015, 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
	*/

	/* **************************************************************
	* Compiler specifics
	****************************************************************/
	#define FORCE_INLINE static __always_inline

	/* **************************************************************
	* Includes
	****************************************************************/
	#include "bitstream.h"
	#include "fse.h"
	#include "zstd_internal.h"
	#include <linux/compiler.h>
	#include <linux/kernel.h>
	#include <linux/string.h> /* memcpy, memset */

	/* **************************************************************
	* Error Management
	****************************************************************/
	#define FSE_isError ERR_isError
	#define FSE_STATIC_ASSERT(c) \
	{ \
	enum { FSE_static_assert = 1 / (int)(!!(c)) }; \
	} /* use only after variable declarations */

	/* **************************************************************
	* Templates
	****************************************************************/
	/*
	designed to be included
	for type-specific functions (template emulation in C)
	Objective is to write these functions only once, for improved maintenance
	*/

	/* safety checks */
	#ifndef FSE_FUNCTION_EXTENSION
	#error "FSE_FUNCTION_EXTENSION must be defined"
	#endif
	#ifndef FSE_FUNCTION_TYPE
	#error "FSE_FUNCTION_TYPE must be defined"
	#endif

	/* Function names */
	#define FSE_CAT(X, Y) X##Y
	#define FSE_FUNCTION_NAME(X, Y) FSE_CAT(X, Y)
	#define FSE_TYPE_NAME(X, Y) FSE_CAT(X, Y)

	/* Function templates */

	size_t FSE_buildDTable_wksp(FSE_DTable dt, const short normalizedCounter, unsigned maxSymbolValue, unsigned tableLog, void *workspace, size_t workspaceSize)
	{
	void const tdPtr = dt + 1; / because dt is unsigned, 32-bits aligned on 32-bits /
	FSE_DECODE_TYPE const tableDecode = (FSE_DECODE_TYPE )(tdPtr);
	U16 symbolNext = (U16 )workspace;

	U32 const maxSV1 = maxSymbolValue + 1;
	U32 const tableSize = 1 << tableLog;
	U32 highThreshold = tableSize - 1;

	/* Sanity Checks */
	if (workspaceSize < sizeof(U16) * (FSE_MAX_SYMBOL_VALUE + 1))
	return ERROR(tableLog_tooLarge);
	if (maxSymbolValue > FSE_MAX_SYMBOL_VALUE)
	return ERROR(maxSymbolValue_tooLarge);
	if (tableLog > FSE_MAX_TABLELOG)
	return ERROR(tableLog_tooLarge);

	/* Init, lay down lowprob symbols */
	{
	FSE_DTableHeader DTableH;
	DTableH.tableLog = (U16)tableLog;
	DTableH.fastMode = 1;
	{
	S16 const largeLimit = (S16)(1 << (tableLog - 1));
	U32 s;
	for (s = 0; s < maxSV1; s++) {
	if (normalizedCounter[s] == -1) {
	tableDecode[highThreshold--].symbol = (FSE_FUNCTION_TYPE)s;
	symbolNext[s] = 1;
	} else {
	if (normalizedCounter[s] >= largeLimit)
	DTableH.fastMode = 0;
	symbolNext[s] = normalizedCounter[s];
	}
	}
	}
	memcpy(dt, &DTableH, sizeof(DTableH));
	}

	/* Spread symbols */
	{
	U32 const tableMask = tableSize - 1;
	U32 const step = FSE_TABLESTEP(tableSize);
	U32 s, position = 0;
	for (s = 0; s < maxSV1; s++) {
	int i;
	for (i = 0; i < normalizedCounter[s]; i++) {
	tableDecode[position].symbol = (FSE_FUNCTION_TYPE)s;
	position = (position + step) & tableMask;
	while (position > highThreshold)
	position = (position + step) & tableMask; /* lowprob area */
	}
	}
	if (position != 0)
	return ERROR(GENERIC); /* position must reach all cells once, otherwise normalizedCounter is incorrect */
	}

	/* Build Decoding table */
	{
	U32 u;
	for (u = 0; u < tableSize; u++) {
	FSE_FUNCTION_TYPE const symbol = (FSE_FUNCTION_TYPE)(tableDecode[u].symbol);
	U16 nextState = symbolNext[symbol]++;
	tableDecode[u].nbBits = (BYTE)(tableLog - BIT_highbit32((U32)nextState));
	tableDecode[u].newState = (U16)((nextState << tableDecode[u].nbBits) - tableSize);
	}
	}

	return 0;
	}

	/-******************************************************
	* Decompression (Byte symbols)
	*********************************************************/
	size_t FSE_buildDTable_rle(FSE_DTable *dt, BYTE symbolValue)
	{
	void *ptr = dt;
	FSE_DTableHeader const DTableH = (FSE_DTableHeader )ptr;
	void *dPtr = dt + 1;
	FSE_decode_t const cell = (FSE_decode_t )dPtr;

	DTableH->tableLog = 0;
	DTableH->fastMode = 0;

	cell->newState = 0;
	cell->symbol = symbolValue;
	cell->nbBits = 0;

	return 0;
	}

	size_t FSE_buildDTable_raw(FSE_DTable *dt, unsigned nbBits)
	{
	void *ptr = dt;
	FSE_DTableHeader const DTableH = (FSE_DTableHeader )ptr;
	void *dPtr = dt + 1;
	FSE_decode_t const dinfo = (FSE_decode_t )dPtr;
	const unsigned tableSize = 1 << nbBits;
	const unsigned tableMask = tableSize - 1;
	const unsigned maxSV1 = tableMask + 1;
	unsigned s;

	/* Sanity checks */
	if (nbBits < 1)
	return ERROR(GENERIC); /* min size */

	/* Build Decoding Table */
	DTableH->tableLog = (U16)nbBits;
	DTableH->fastMode = 1;
	for (s = 0; s < maxSV1; s++) {
	dinfo[s].newState = 0;
	dinfo[s].symbol = (BYTE)s;
	dinfo[s].nbBits = (BYTE)nbBits;
	}

	return 0;
	}

	FORCE_INLINE size_t FSE_decompress_usingDTable_generic(void dst, size_t maxDstSize, const void cSrc, size_t cSrcSize, const FSE_DTable *dt,
	const unsigned fast)
	{
	BYTE const ostart = (BYTE )dst;
	BYTE *op = ostart;
	BYTE *const omax = op + maxDstSize;
	BYTE *const olimit = omax - 3;

	BIT_DStream_t bitD;
	FSE_DState_t state1;
	FSE_DState_t state2;

	/* Init */
	CHECK_F(BIT_initDStream(&bitD, cSrc, cSrcSize));

	FSE_initDState(&state1, &bitD, dt);
	FSE_initDState(&state2, &bitD, dt);

	#define FSE_GETSYMBOL(statePtr) fast ? FSE_decodeSymbolFast(statePtr, &bitD) : FSE_decodeSymbol(statePtr, &bitD)

	/* 4 symbols per loop */
	for (; (BIT_reloadDStream(&bitD) == BIT_DStream_unfinished) & (op < olimit); op += 4) {
	op[0] = FSE_GETSYMBOL(&state1);

	if (FSE_MAX_TABLELOG * 2 + 7 > sizeof(bitD.bitContainer) * 8) /* This test must be static */
	BIT_reloadDStream(&bitD);

	op[1] = FSE_GETSYMBOL(&state2);

	if (FSE_MAX_TABLELOG * 4 + 7 > sizeof(bitD.bitContainer) * 8) /* This test must be static */
	{
	if (BIT_reloadDStream(&bitD) > BIT_DStream_unfinished) {
	op += 2;
	break;
	}
	}

	op[2] = FSE_GETSYMBOL(&state1);

	if (FSE_MAX_TABLELOG * 2 + 7 > sizeof(bitD.bitContainer) * 8) /* This test must be static */
	BIT_reloadDStream(&bitD);

	op[3] = FSE_GETSYMBOL(&state2);
	}

	/* tail */
	/* note : BIT_reloadDStream(&bitD) >= FSE_DStream_partiallyFilled; Ends at exactly BIT_DStream_completed */
	while (1) {
	if (op > (omax - 2))
	return ERROR(dstSize_tooSmall);
	*op++ = FSE_GETSYMBOL(&state1);
	if (BIT_reloadDStream(&bitD) == BIT_DStream_overflow) {
	*op++ = FSE_GETSYMBOL(&state2);
	break;
	}

	if (op > (omax - 2))
	return ERROR(dstSize_tooSmall);
	*op++ = FSE_GETSYMBOL(&state2);
	if (BIT_reloadDStream(&bitD) == BIT_DStream_overflow) {
	*op++ = FSE_GETSYMBOL(&state1);
	break;
	}
	}

	return op - ostart;
	}

	size_t FSE_decompress_usingDTable(void dst, size_t originalSize, const void cSrc, size_t cSrcSize, const FSE_DTable *dt)
	{
	const void *ptr = dt;
	const FSE_DTableHeader DTableH = (const FSE_DTableHeader )ptr;
	const U32 fastMode = DTableH->fastMode;

	/* select fast mode (static) */
	if (fastMode)
	return FSE_decompress_usingDTable_generic(dst, originalSize, cSrc, cSrcSize, dt, 1);
	return FSE_decompress_usingDTable_generic(dst, originalSize, cSrc, cSrcSize, dt, 0);
	}

	size_t FSE_decompress_wksp(void dst, size_t dstCapacity, const void cSrc, size_t cSrcSize, unsigned maxLog, void *workspace, size_t workspaceSize)
	{
	const BYTE const istart = (const BYTE )cSrc;
	const BYTE *ip = istart;
	unsigned tableLog;
	unsigned maxSymbolValue = FSE_MAX_SYMBOL_VALUE;
	size_t NCountLength;

	FSE_DTable *dt;
	short *counting;
	size_t spaceUsed32 = 0;

	FSE_STATIC_ASSERT(sizeof(FSE_DTable) == sizeof(U32));

	dt = (FSE_DTable )((U32 )workspace + spaceUsed32);
	spaceUsed32 += FSE_DTABLE_SIZE_U32(maxLog);
	counting = (short )((U32 )workspace + spaceUsed32);
	spaceUsed32 += ALIGN(sizeof(short) * (FSE_MAX_SYMBOL_VALUE + 1), sizeof(U32)) >> 2;

	if ((spaceUsed32 << 2) > workspaceSize)
	return ERROR(tableLog_tooLarge);
	workspace = (U32 *)workspace + spaceUsed32;
	workspaceSize -= (spaceUsed32 << 2);

	/* normal FSE decoding mode */
	NCountLength = FSE_readNCount(counting, &maxSymbolValue, &tableLog, istart, cSrcSize);
	if (FSE_isError(NCountLength))
	return NCountLength;
	// if (NCountLength >= cSrcSize) return ERROR(srcSize_wrong); /* too small input size; supposed to be already checked in NCountLength, only remaining
	// case : NCountLength==cSrcSize */
	if (tableLog > maxLog)
	return ERROR(tableLog_tooLarge);
	ip += NCountLength;
	cSrcSize -= NCountLength;

	CHECK_F(FSE_buildDTable_wksp(dt, counting, maxSymbolValue, tableLog, workspace, workspaceSize));

	return FSE_decompress_usingDTable(dst, dstCapacity, ip, cSrcSize, dt); /* always return, even if it is an error code */
	}