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
FSE_buildDTable_wksp(FSE_DTable * dt,const short * normalizedCounter,unsigned maxSymbolValue,unsigned tableLog,void * workspace,size_t workspaceSize)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 *********************************************************/
FSE_buildDTable_rle(FSE_DTable * dt,BYTE symbolValue)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
FSE_buildDTable_raw(FSE_DTable * dt,unsigned nbBits)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
FSE_decompress_usingDTable_generic(void * dst,size_t maxDstSize,const void * cSrc,size_t cSrcSize,const FSE_DTable * dt,const unsigned fast)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
FSE_decompress_usingDTable(void * dst,size_t originalSize,const void * cSrc,size_t cSrcSize,const FSE_DTable * dt)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
FSE_decompress_wksp(void * dst,size_t dstCapacity,const void * cSrc,size_t cSrcSize,unsigned maxLog,void * workspace,size_t workspaceSize)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 }
326
