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 "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
  88size_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*********************************************************/
 163size_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
 180size_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
 207FORCE_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
 275size_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
 287size_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}
 326