lib/zstd/fse_decompress.c

   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 "zstd_internal.h"
  51 #include <linux/compiler.h>
  52 #include <linux/kernel.h>
  53 #include <linux/string.h> /* memcpy, memset */
  54
  55 /* **************************************************************
  56 *  Error Management
  57 ****************************************************************/
  58 #define FSE_isError ERR_isError
  59 #define FSE_STATIC_ASSERT(c)                                   \
  60         {                                                      \
  61                 enum { FSE_static_assert = 1 / (int)(!!(c)) }; \
  62         } /* use only *after* variable declarations */
  63
  64 /* **************************************************************
  65 *  Templates
  66 ****************************************************************/
  67 /*
  68   designed to be included
  69   for type-specific functions (template emulation in C)
  70   Objective is to write these functions only once, for improved maintenance
  71 */
  72
  73 /* safety checks */
  74 #ifndef FSE_FUNCTION_EXTENSION
  75 #error "FSE_FUNCTION_EXTENSION must be defined"
  76 #endif
  77 #ifndef FSE_FUNCTION_TYPE
  78 #error "FSE_FUNCTION_TYPE must be defined"
  79 #endif
  80
  81 /* Function names */
  82 #define FSE_CAT(X, Y) X##Y
  83 #define FSE_FUNCTION_NAME(X, Y) FSE_CAT(X, Y)
  84 #define FSE_TYPE_NAME(X, Y) FSE_CAT(X, Y)
  85
  86 /* Function templates */
  87
  88 size_t FSE_buildDTable_wksp(FSE_DTable *dt, const short *normalizedCounter, unsigned maxSymbolValue, unsigned tableLog, void *workspace, size_t workspaceSize)
  89 {
  90         void *const tdPtr = dt + 1; /* because *dt is unsigned, 32-bits aligned on 32-bits */
  91         FSE_DECODE_TYPE *const tableDecode = (FSE_DECODE_TYPE *)(tdPtr);
  92         U16 *symbolNext = (U16 *)workspace;
  93
  94         U32 const maxSV1 = maxSymbolValue + 1;
  95         U32 const tableSize = 1 << tableLog;
  96         U32 highThreshold = tableSize - 1;
  97
  98         /* Sanity Checks */
  99         if (workspaceSize < sizeof(U16) * (FSE_MAX_SYMBOL_VALUE + 1))
 100                 return ERROR(tableLog_tooLarge);
 101         if (maxSymbolValue > FSE_MAX_SYMBOL_VALUE)
 102                 return ERROR(maxSymbolValue_tooLarge);
 103         if (tableLog > FSE_MAX_TABLELOG)
 104                 return ERROR(tableLog_tooLarge);
 105
 106         /* Init, lay down lowprob symbols */
 107         {
 108                 FSE_DTableHeader DTableH;
 109                 DTableH.tableLog = (U16)tableLog;
 110                 DTableH.fastMode = 1;
 111                 {
 112                         S16 const largeLimit = (S16)(1 << (tableLog - 1));
 113                         U32 s;
 114                         for (s = 0; s < maxSV1; s++) {
 115                                 if (normalizedCounter[s] == -1) {
 116                                         tableDecode[highThreshold--].symbol = (FSE_FUNCTION_TYPE)s;
 117                                         symbolNext[s] = 1;
 118                                 } else {
 119                                         if (normalizedCounter[s] >= largeLimit)
 120                                                 DTableH.fastMode = 0;
 121                                         symbolNext[s] = normalizedCounter[s];
 122                                 }
 123                         }
 124                 }
 125                 memcpy(dt, &DTableH, sizeof(DTableH));
 126         }
 127
 128         /* Spread symbols */
 129         {
 130                 U32 const tableMask = tableSize - 1;
 131                 U32 const step = FSE_TABLESTEP(tableSize);
 132                 U32 s, position = 0;
 133                 for (s = 0; s < maxSV1; s++) {
 134                         int i;
 135                         for (i = 0; i < normalizedCounter[s]; i++) {
 136                                 tableDecode[position].symbol = (FSE_FUNCTION_TYPE)s;
 137                                 position = (position + step) & tableMask;
 138                                 while (position > highThreshold)
 139                                         position = (position + step) & tableMask; /* lowprob area */
 140                         }
 141                 }
 142                 if (position != 0)
 143                         return ERROR(GENERIC); /* position must reach all cells once, otherwise normalizedCounter is incorrect */
 144         }
 145
 146         /* Build Decoding table */
 147         {
 148                 U32 u;
 149                 for (u = 0; u < tableSize; u++) {
 150                         FSE_FUNCTION_TYPE const symbol = (FSE_FUNCTION_TYPE)(tableDecode[u].symbol);
 151                         U16 nextState = symbolNext[symbol]++;
 152                         tableDecode[u].nbBits = (BYTE)(tableLog - BIT_highbit32((U32)nextState));
 153                         tableDecode[u].newState = (U16)((nextState << tableDecode[u].nbBits) - tableSize);
 154                 }
 155         }
 156
 157         return 0;
 158 }
 159
 160 /*-*******************************************************
 161 *  Decompression (Byte symbols)
 162 *********************************************************/
 163 size_t FSE_buildDTable_rle(FSE_DTable *dt, BYTE symbolValue)
 164 {
 165         void *ptr = dt;
 166         FSE_DTableHeader *const DTableH = (FSE_DTableHeader *)ptr;
 167         void *dPtr = dt + 1;
 168         FSE_decode_t *const cell = (FSE_decode_t *)dPtr;
 169
 170         DTableH->tableLog = 0;
 171         DTableH->fastMode = 0;
 172
 173         cell->newState = 0;
 174         cell->symbol = symbolValue;
 175         cell->nbBits = 0;
 176
 177         return 0;
 178 }
 179
 180 size_t FSE_buildDTable_raw(FSE_DTable *dt, unsigned nbBits)
 181 {
 182         void *ptr = dt;
 183         FSE_DTableHeader *const DTableH = (FSE_DTableHeader *)ptr;
 184         void *dPtr = dt + 1;
 185         FSE_decode_t *const dinfo = (FSE_decode_t *)dPtr;
 186         const unsigned tableSize = 1 << nbBits;
 187         const unsigned tableMask = tableSize - 1;
 188         const unsigned maxSV1 = tableMask + 1;
 189         unsigned s;
 190
 191         /* Sanity checks */
 192         if (nbBits < 1)
 193                 return ERROR(GENERIC); /* min size */
 194
 195         /* Build Decoding Table */
 196         DTableH->tableLog = (U16)nbBits;
 197         DTableH->fastMode = 1;
 198         for (s = 0; s < maxSV1; s++) {
 199                 dinfo[s].newState = 0;
 200                 dinfo[s].symbol = (BYTE)s;
 201                 dinfo[s].nbBits = (BYTE)nbBits;
 202         }
 203
 204         return 0;
 205 }
 206
 207 FORCE_INLINE size_t FSE_decompress_usingDTable_generic(void *dst, size_t maxDstSize, const void *cSrc, size_t cSrcSize, const FSE_DTable *dt,
 208                                                        const unsigned fast)
 209 {
 210         BYTE *const ostart = (BYTE *)dst;
 211         BYTE *op = ostart;
 212         BYTE *const omax = op + maxDstSize;
 213         BYTE *const olimit = omax - 3;
 214
 215         BIT_DStream_t bitD;
 216         FSE_DState_t state1;
 217         FSE_DState_t state2;
 218
 219         /* Init */
 220         CHECK_F(BIT_initDStream(&bitD, cSrc, cSrcSize));
 221
 222         FSE_initDState(&state1, &bitD, dt);
 223         FSE_initDState(&state2, &bitD, dt);
 224
 225 #define FSE_GETSYMBOL(statePtr) fast ? FSE_decodeSymbolFast(statePtr, &bitD) : FSE_decodeSymbol(statePtr, &bitD)
 226
 227         /* 4 symbols per loop */
 228         for (; (BIT_reloadDStream(&bitD) == BIT_DStream_unfinished) & (op < olimit); op += 4) {
 229                 op[0] = FSE_GETSYMBOL(&state1);
 230
 231                 if (FSE_MAX_TABLELOG * 2 + 7 > sizeof(bitD.bitContainer) * 8) /* This test must be static */
 232                         BIT_reloadDStream(&bitD);
 233
 234                 op[1] = FSE_GETSYMBOL(&state2);
 235
 236                 if (FSE_MAX_TABLELOG * 4 + 7 > sizeof(bitD.bitContainer) * 8) /* This test must be static */
 237                 {
 238                         if (BIT_reloadDStream(&bitD) > BIT_DStream_unfinished) {
 239                                 op += 2;
 240                                 break;
 241                         }
 242                 }
 243
 244                 op[2] = FSE_GETSYMBOL(&state1);
 245
 246                 if (FSE_MAX_TABLELOG * 2 + 7 > sizeof(bitD.bitContainer) * 8) /* This test must be static */
 247                         BIT_reloadDStream(&bitD);
 248
 249                 op[3] = FSE_GETSYMBOL(&state2);
 250         }
 251
 252         /* tail */
 253         /* note : BIT_reloadDStream(&bitD) >= FSE_DStream_partiallyFilled; Ends at exactly BIT_DStream_completed */
 254         while (1) {
 255                 if (op > (omax - 2))
 256                         return ERROR(dstSize_tooSmall);
 257                 *op++ = FSE_GETSYMBOL(&state1);
 258                 if (BIT_reloadDStream(&bitD) == BIT_DStream_overflow) {
 259                         *op++ = FSE_GETSYMBOL(&state2);
 260                         break;
 261                 }
 262
 263                 if (op > (omax - 2))
 264                         return ERROR(dstSize_tooSmall);
 265                 *op++ = FSE_GETSYMBOL(&state2);
 266                 if (BIT_reloadDStream(&bitD) == BIT_DStream_overflow) {
 267                         *op++ = FSE_GETSYMBOL(&state1);
 268                         break;
 269                 }
 270         }
 271
 272         return op - ostart;
 273 }
 274
 275 size_t FSE_decompress_usingDTable(void *dst, size_t originalSize, const void *cSrc, size_t cSrcSize, const FSE_DTable *dt)
 276 {
 277         const void *ptr = dt;
 278         const FSE_DTableHeader *DTableH = (const FSE_DTableHeader *)ptr;
 279         const U32 fastMode = DTableH->fastMode;
 280
 281         /* select fast mode (static) */
 282         if (fastMode)
 283                 return FSE_decompress_usingDTable_generic(dst, originalSize, cSrc, cSrcSize, dt, 1);
 284         return FSE_decompress_usingDTable_generic(dst, originalSize, cSrc, cSrcSize, dt, 0);
 285 }
 286
 287 size_t FSE_decompress_wksp(void *dst, size_t dstCapacity, const void *cSrc, size_t cSrcSize, unsigned maxLog, void *workspace, size_t workspaceSize)
 288 {
 289         const BYTE *const istart = (const BYTE *)cSrc;
 290         const BYTE *ip = istart;
 291         unsigned tableLog;
 292         unsigned maxSymbolValue = FSE_MAX_SYMBOL_VALUE;
 293         size_t NCountLength;
 294
 295         FSE_DTable *dt;
 296         short *counting;
 297         size_t spaceUsed32 = 0;
 298
 299         FSE_STATIC_ASSERT(sizeof(FSE_DTable) == sizeof(U32));
 300
 301         dt = (FSE_DTable *)((U32 *)workspace + spaceUsed32);
 302         spaceUsed32 += FSE_DTABLE_SIZE_U32(maxLog);
 303         counting = (short *)((U32 *)workspace + spaceUsed32);
 304         spaceUsed32 += ALIGN(sizeof(short) * (FSE_MAX_SYMBOL_VALUE + 1), sizeof(U32)) >> 2;
 305
 306         if ((spaceUsed32 << 2) > workspaceSize)
 307                 return ERROR(tableLog_tooLarge);
 308         workspace = (U32 *)workspace + spaceUsed32;
 309         workspaceSize -= (spaceUsed32 << 2);
 310
 311         /* normal FSE decoding mode */
 312         NCountLength = FSE_readNCount(counting, &maxSymbolValue, &tableLog, istart, cSrcSize);
 313         if (FSE_isError(NCountLength))
 314                 return NCountLength;
 315         // if (NCountLength >= cSrcSize) return ERROR(srcSize_wrong);   /* too small input size; supposed to be already checked in NCountLength, only remaining
 316         // case : NCountLength==cSrcSize */
 317         if (tableLog > maxLog)
 318                 return ERROR(tableLog_tooLarge);
 319         ip += NCountLength;
 320         cSrcSize -= NCountLength;
 321
 322         CHECK_F(FSE_buildDTable_wksp(dt, counting, maxSymbolValue, tableLog, workspace, workspaceSize));
 323
 324         return FSE_decompress_usingDTable(dst, dstCapacity, ip, cSrcSize, dt); /* always return, even if it is an error code */
 325 }