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 <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
  95 size_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 *********************************************************/
 170 size_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
 187 size_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
 214 FORCE_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
 282 size_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
 294 size_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 }