LXR linux/lib/zstd/fse

   1/*
   2 * FSE : Finite State Entropy decoder
   3 * Copyright (C) 2013-2015, Yann Collet.
   4 *
   5 * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
   6 *
   7 * Redistribution and use in source and binary forms, with or without
   8 * modification, are permitted provided that the following conditions are
   9 * met:
  10 *
  11 *   * Redistributions of source code must retain the above copyright
  12 * notice, this list of conditions and the following disclaimer.
  13 *   * Redistributions in binary form must reproduce the above
  14 * copyright notice, this list of conditions and the following disclaimer
  15 * in the documentation and/or other materials provided with the
  16 * distribution.
  17 *
  18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29 *
  30 * This program is free software; you can redistribute it and/or modify it under
  31 * the terms of the GNU General Public License version 2 as published by the
  32 * Free Software Foundation. This program is dual-licensed; you may select
  33 * either version 2 of the GNU General Public License ("GPL") or BSD license
  34 * ("BSD").
  35 *
  36 * You can contact the author at :
  37 * - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
  38 */
  39
  40/* **************************************************************
  41*  Compiler specifics
  42****************************************************************/
  43#define FORCE_INLINE static __always_inline
  44
  45/* **************************************************************
  46*  Includes
  47****************************************************************/
  48#include "bitstream.h"
  49#include "fse.h"
  50#include <linux/compiler.h>
  51#include <linux/kernel.h>
  52#include <linux/string.h> /* memcpy, memset */
  53
  54/* **************************************************************
  55*  Error Management
  56****************************************************************/
  57#define FSE_isError ERR_isError
  58#define FSE_STATIC_ASSERT(c)                                   \
  59        {                                                      \
  60                enum { FSE_static_assert = 1 / (int)(!!(c)) }; \
  61        } /* use only *after* variable declarations */
  62
  63/* check and forward error code */
  64#define CHECK_F(f)                  \
  65        {                           \
  66                size_t const e = f; \
  67                if (FSE_isError(e)) \
  68                        return e;   \
  69        }
  70
  71/* **************************************************************
  72*  Templates
  73****************************************************************/
  74/*
  75  designed to be included
  76  for type-specific functions (template emulation in C)
  77  Objective is to write these functions only once, for improved maintenance
  78*/
  79
  80/* safety checks */
  81#ifndef FSE_FUNCTION_EXTENSION
  82#error "FSE_FUNCTION_EXTENSION must be defined"
  83#endif
  84#ifndef FSE_FUNCTION_TYPE
  85#error "FSE_FUNCTION_TYPE must be defined"
  86#endif
  87
  88/* Function names */
  89#define FSE_CAT(X, Y) X##Y
  90#define FSE_FUNCTION_NAME(X, Y) FSE_CAT(X, Y)
  91#define FSE_TYPE_NAME(X, Y) FSE_CAT(X, Y)
  92
  93/* Function templates */
  94
  95size_t FSE_buildDTable_wksp(FSE_DTable *dt, const short *normalizedCounter, unsigned maxSymbolValue, unsigned tableLog, void *workspace, size_t workspaceSize)
  96{
  97        void *const tdPtr = dt + 1; /* because *dt is unsigned, 32-bits aligned on 32-bits */
  98        FSE_DECODE_TYPE *const tableDecode = (FSE_DECODE_TYPE *)(tdPtr);
  99        U16 *symbolNext = (U16 *)workspace;
 100
 101        U32 const maxSV1 = maxSymbolValue + 1;
 102        U32 const tableSize = 1 << tableLog;
 103        U32 highThreshold = tableSize - 1;
 104
 105        /* Sanity Checks */
 106        if (workspaceSize < sizeof(U16) * (FSE_MAX_SYMBOL_VALUE + 1))
 107                return ERROR(tableLog_tooLarge);
 108        if (maxSymbolValue > FSE_MAX_SYMBOL_VALUE)
 109                return ERROR(maxSymbolValue_tooLarge);
 110        if (tableLog > FSE_MAX_TABLELOG)
 111                return ERROR(tableLog_tooLarge);
 112
 113        /* Init, lay down lowprob symbols */
 114        {
 115                FSE_DTableHeader DTableH;
 116                DTableH.tableLog = (U16)tableLog;
 117                DTableH.fastMode = 1;
 118                {
 119                        S16 const largeLimit = (S16)(1 << (tableLog - 1));
 120                        U32 s;
 121                        for (s = 0; s < maxSV1; s++) {
 122                                if (normalizedCounter[s] == -1) {
 123                                        tableDecode[highThreshold--].symbol = (FSE_FUNCTION_TYPE)s;
 124                                        symbolNext[s] = 1;
 125                                } else {
 126                                        if (normalizedCounter[s] >= largeLimit)
 127                                                DTableH.fastMode = 0;
 128                                        symbolNext[s] = normalizedCounter[s];
 129                                }
 130                        }
 131                }
 132                memcpy(dt, &DTableH, sizeof(DTableH));
 133        }
 134
 135        /* Spread symbols */
 136        {
 137                U32 const tableMask = tableSize - 1;
 138                U32 const step = FSE_TABLESTEP(tableSize);
 139                U32 s, position = 0;
 140                for (s = 0; s < maxSV1; s++) {
 141                        int i;
 142                        for (i = 0; i < normalizedCounter[s]; i++) {
 143                                tableDecode[position].symbol = (FSE_FUNCTION_TYPE)s;
 144                                position = (position + step) & tableMask;
 145                                while (position > highThreshold)
 146                                        position = (position + step) & tableMask; /* lowprob area */
 147                        }
 148                }
 149                if (position != 0)
 150                        return ERROR(GENERIC); /* position must reach all cells once, otherwise normalizedCounter is incorrect */
 151        }
 152
 153        /* Build Decoding table */
 154        {
 155                U32 u;
 156                for (u = 0; u < tableSize; u++) {
 157                        FSE_FUNCTION_TYPE const symbol = (FSE_FUNCTION_TYPE)(tableDecode[u].symbol);
 158                        U16 nextState = symbolNext[symbol]++;
 159                        tableDecode[u].nbBits = (BYTE)(tableLog - BIT_highbit32((U32)nextState));
 160                        tableDecode[u].newState = (U16)((nextState << tableDecode[u].nbBits) - tableSize);
 161                }
 162        }
 163
 164        return 0;
 165}
 166
 167/*-*******************************************************
 168*  Decompression (Byte symbols)
 169*********************************************************/
 170size_t FSE_buildDTable_rle(FSE_DTable *dt, BYTE symbolValue)
 171{
 172        void *ptr = dt;
 173        FSE_DTableHeader *const DTableH = (FSE_DTableHeader *)ptr;
 174        void *dPtr = dt + 1;
 175        FSE_decode_t *const cell = (FSE_decode_t *)dPtr;
 176
 177        DTableH->tableLog = 0;
 178        DTableH->fastMode = 0;
 179
 180        cell->newState = 0;
 181        cell->symbol = symbolValue;
 182        cell->nbBits = 0;
 183
 184        return 0;
 185}
 186
 187size_t FSE_buildDTable_raw(FSE_DTable *dt, unsigned nbBits)
 188{
 189        void *ptr = dt;
 190        FSE_DTableHeader *const DTableH = (FSE_DTableHeader *)ptr;
 191        void *dPtr = dt + 1;
 192        FSE_decode_t *const dinfo = (FSE_decode_t *)dPtr;
 193        const unsigned tableSize = 1 << nbBits;
 194        const unsigned tableMask = tableSize - 1;
 195        const unsigned maxSV1 = tableMask + 1;
 196        unsigned s;
 197
 198        /* Sanity checks */
 199        if (nbBits < 1)
 200                return ERROR(GENERIC); /* min size */
 201
 202        /* Build Decoding Table */
 203        DTableH->tableLog = (U16)nbBits;
 204        DTableH->fastMode = 1;
 205        for (s = 0; s < maxSV1; s++) {
 206                dinfo[s].newState = 0;
 207                dinfo[s].symbol = (BYTE)s;
 208                dinfo[s].nbBits = (BYTE)nbBits;
 209        }
 210
 211        return 0;
 212}
 213
 214FORCE_INLINE size_t FSE_decompress_usingDTable_generic(void *dst, size_t maxDstSize, const void *cSrc, size_t cSrcSize, const FSE_DTable *dt,
 215                                                       const unsigned fast)
 216{
 217        BYTE *const ostart = (BYTE *)dst;
 218        BYTE *op = ostart;
 219        BYTE *const omax = op + maxDstSize;
 220        BYTE *const olimit = omax - 3;
 221
 222        BIT_DStream_t bitD;
 223        FSE_DState_t state1;
 224        FSE_DState_t state2;
 225
 226        /* Init */
 227        CHECK_F(BIT_initDStream(&bitD, cSrc, cSrcSize));
 228
 229        FSE_initDState(&state1, &bitD, dt);
 230        FSE_initDState(&state2, &bitD, dt);
 231
 232#define FSE_GETSYMBOL(statePtr) fast ? FSE_decodeSymbolFast(statePtr, &bitD) : FSE_decodeSymbol(statePtr, &bitD)
 233
 234        /* 4 symbols per loop */
 235        for (; (BIT_reloadDStream(&bitD) == BIT_DStream_unfinished) & (op < olimit); op += 4) {
 236                op[0] = FSE_GETSYMBOL(&state1);
 237
 238                if (FSE_MAX_TABLELOG * 2 + 7 > sizeof(bitD.bitContainer) * 8) /* This test must be static */
 239                        BIT_reloadDStream(&bitD);
 240
 241                op[1] = FSE_GETSYMBOL(&state2);
 242
 243                if (FSE_MAX_TABLELOG * 4 + 7 > sizeof(bitD.bitContainer) * 8) /* This test must be static */
 244                {
 245                        if (BIT_reloadDStream(&bitD) > BIT_DStream_unfinished) {
 246                                op += 2;
 247                                break;
 248                        }
 249                }
 250
 251                op[2] = FSE_GETSYMBOL(&state1);
 252
 253                if (FSE_MAX_TABLELOG * 2 + 7 > sizeof(bitD.bitContainer) * 8) /* This test must be static */
 254                        BIT_reloadDStream(&bitD);
 255
 256                op[3] = FSE_GETSYMBOL(&state2);
 257        }
 258
 259        /* tail */
 260        /* note : BIT_reloadDStream(&bitD) >= FSE_DStream_partiallyFilled; Ends at exactly BIT_DStream_completed */
 261        while (1) {
 262                if (op > (omax - 2))
 263                        return ERROR(dstSize_tooSmall);
 264                *op++ = FSE_GETSYMBOL(&state1);
 265                if (BIT_reloadDStream(&bitD) == BIT_DStream_overflow) {
 266                        *op++ = FSE_GETSYMBOL(&state2);
 267                        break;
 268                }
 269
 270                if (op > (omax - 2))
 271                        return ERROR(dstSize_tooSmall);
 272                *op++ = FSE_GETSYMBOL(&state2);
 273                if (BIT_reloadDStream(&bitD) == BIT_DStream_overflow) {
 274                        *op++ = FSE_GETSYMBOL(&state1);
 275                        break;
 276                }
 277        }
 278
 279        return op - ostart;
 280}
 281
 282size_t FSE_decompress_usingDTable(void *dst, size_t originalSize, const void *cSrc, size_t cSrcSize, const FSE_DTable *dt)
 283{
 284        const void *ptr = dt;
 285        const FSE_DTableHeader *DTableH = (const FSE_DTableHeader *)ptr;
 286        const U32 fastMode = DTableH->fastMode;
 287
 288        /* select fast mode (static) */
 289        if (fastMode)
 290                return FSE_decompress_usingDTable_generic(dst, originalSize, cSrc, cSrcSize, dt, 1);
 291        return FSE_decompress_usingDTable_generic(dst, originalSize, cSrc, cSrcSize, dt, 0);
 292}
 293
 294size_t FSE_decompress_wksp(void *dst, size_t dstCapacity, const void *cSrc, size_t cSrcSize, unsigned maxLog, void *workspace, size_t workspaceSize)
 295{
 296        const BYTE *const istart = (const BYTE *)cSrc;
 297        const BYTE *ip = istart;
 298        unsigned tableLog;
 299        unsigned maxSymbolValue = FSE_MAX_SYMBOL_VALUE;
 300        size_t NCountLength;
 301
 302        FSE_DTable *dt;
 303        short *counting;
 304        size_t spaceUsed32 = 0;
 305
 306        FSE_STATIC_ASSERT(sizeof(FSE_DTable) == sizeof(U32));
 307
 308        dt = (FSE_DTable *)((U32 *)workspace + spaceUsed32);
 309        spaceUsed32 += FSE_DTABLE_SIZE_U32(maxLog);
 310        counting = (short *)((U32 *)workspace + spaceUsed32);
 311        spaceUsed32 += ALIGN(sizeof(short) * (FSE_MAX_SYMBOL_VALUE + 1), sizeof(U32)) >> 2;
 312
 313        if ((spaceUsed32 << 2) > workspaceSize)
 314                return ERROR(tableLog_tooLarge);
 315        workspace = (U32 *)workspace + spaceUsed32;
 316        workspaceSize -= (spaceUsed32 << 2);
 317
 318        /* normal FSE decoding mode */
 319        NCountLength = FSE_readNCount(counting, &maxSymbolValue, &tableLog, istart, cSrcSize);
 320        if (FSE_isError(NCountLength))
 321                return NCountLength;
 322        // if (NCountLength >= cSrcSize) return ERROR(srcSize_wrong);   /* too small input size; supposed to be already checked in NCountLength, only remaining
 323        // case : NCountLength==cSrcSize */
 324        if (tableLog > maxLog)
 325                return ERROR(tableLog_tooLarge);
 326        ip += NCountLength;
 327        cSrcSize -= NCountLength;
 328
 329        CHECK_F(FSE_buildDTable_wksp(dt, counting, maxSymbolValue, tableLog, workspace, workspaceSize));
 330
 331        return FSE_decompress_usingDTable(dst, dstCapacity, ip, cSrcSize, dt); /* always return, even if it is an error code */
 332}
 333