1 /* ******************************************************************
2 * FSE : Finite State Entropy encoder
3 * Copyright (c) 2013-2020, Yann Collet, Facebook, Inc.
4 *
5 * You can contact the author at :
6 * - FSE source repository : https://github.com/Cyan4973/FiniteStateEntropy
7 * - Public forum : https://groups.google.com/forum/#!forum/lz4c
8 *
9 * This source code is licensed under both the BSD-style license (found in the
10 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
11 * in the COPYING file in the root directory of this source tree).
12 * You may select, at your option, one of the above-listed licenses.
13 ****************************************************************** */
14
15 /* **************************************************************
16 * Includes
17 ****************************************************************/
18 #include <stdlib.h> /* malloc, free, qsort */
19 #include <string.h> /* memcpy, memset */
20 #include "compiler.h"
21 #include "mem.h" /* U32, U16, etc. */
22 #include "debug.h" /* assert, DEBUGLOG */
23 #include "hist.h" /* HIST_count_wksp */
24 #include "bitstream.h"
25 #define FSE_STATIC_LINKING_ONLY
26 #include "fse.h"
27 #include "error_private.h"
28 #include <ntifs.h>
29 #include <ntddk.h>
30
31
32 /* **************************************************************
33 * Error Management
34 ****************************************************************/
35 #define FSE_isError ERR_isError
36
37
38 /* **************************************************************
39 * Templates
40 ****************************************************************/
41 /*
42 designed to be included
43 for type-specific functions (template emulation in C)
44 Objective is to write these functions only once, for improved maintenance
45 */
46
47 /* safety checks */
48 #ifndef FSE_FUNCTION_EXTENSION
49 # error "FSE_FUNCTION_EXTENSION must be defined"
50 #endif
51 #ifndef FSE_FUNCTION_TYPE
52 # error "FSE_FUNCTION_TYPE must be defined"
53 #endif
54
55 /* Function names */
56 #define FSE_CAT(X,Y) X##Y
57 #define FSE_FUNCTION_NAME(X,Y) FSE_CAT(X,Y)
58 #define FSE_TYPE_NAME(X,Y) FSE_CAT(X,Y)
59
60 #define FSEC_ALLOC_TAG 0x64455346 // "FSEc"
61
62 /* Function templates */
63
64 /* FSE_buildCTable_wksp() :
65 * Same as FSE_buildCTable(), but using an externally allocated scratch buffer (`workSpace`).
66 * wkspSize should be sized to handle worst case situation, which is `1<<max_tableLog * sizeof(FSE_FUNCTION_TYPE)`
67 * workSpace must also be properly aligned with FSE_FUNCTION_TYPE requirements
68 */
FSE_buildCTable_wksp(FSE_CTable * ct,const short * normalizedCounter,unsigned maxSymbolValue,unsigned tableLog,void * workSpace,size_t wkspSize)69 size_t FSE_buildCTable_wksp(FSE_CTable* ct,
70 const short* normalizedCounter, unsigned maxSymbolValue, unsigned tableLog,
71 void* workSpace, size_t wkspSize)
72 {
73 U32 const tableSize = 1 << tableLog;
74 U32 const tableMask = tableSize - 1;
75 void* const ptr = ct;
76 U16* const tableU16 = ( (U16*) ptr) + 2;
77 void* const FSCT = ((U32*)ptr) + 1 /* header */ + (tableLog ? tableSize>>1 : 1) ;
78 FSE_symbolCompressionTransform* const symbolTT = (FSE_symbolCompressionTransform*) (FSCT);
79 U32 const step = FSE_TABLESTEP(tableSize);
80 U32 cumul[FSE_MAX_SYMBOL_VALUE+2];
81
82 FSE_FUNCTION_TYPE* const tableSymbol = (FSE_FUNCTION_TYPE*)workSpace;
83 U32 highThreshold = tableSize-1;
84
85 /* CTable header */
86 if (((size_t)1 << tableLog) * sizeof(FSE_FUNCTION_TYPE) > wkspSize) return ERROR(tableLog_tooLarge);
87 tableU16[-2] = (U16) tableLog;
88 tableU16[-1] = (U16) maxSymbolValue;
89 assert(tableLog < 16); /* required for threshold strategy to work */
90
91 /* For explanations on how to distribute symbol values over the table :
92 * http://fastcompression.blogspot.fr/2014/02/fse-distributing-symbol-values.html */
93
94 #ifdef __clang_analyzer__
95 memset(tableSymbol, 0, sizeof(*tableSymbol) * tableSize); /* useless initialization, just to keep scan-build happy */
96 #endif
97
98 /* symbol start positions */
99 { U32 u;
100 cumul[0] = 0;
101 for (u=1; u <= maxSymbolValue+1; u++) {
102 if (normalizedCounter[u-1]==-1) { /* Low proba symbol */
103 cumul[u] = cumul[u-1] + 1;
104 tableSymbol[highThreshold--] = (FSE_FUNCTION_TYPE)(u-1);
105 } else {
106 cumul[u] = cumul[u-1] + normalizedCounter[u-1];
107 } }
108 cumul[maxSymbolValue+1] = tableSize+1;
109 }
110
111 /* Spread symbols */
112 { U32 position = 0;
113 U32 symbol;
114 for (symbol=0; symbol<=maxSymbolValue; symbol++) {
115 int nbOccurrences;
116 int const freq = normalizedCounter[symbol];
117 for (nbOccurrences=0; nbOccurrences<freq; nbOccurrences++) {
118 tableSymbol[position] = (FSE_FUNCTION_TYPE)symbol;
119 position = (position + step) & tableMask;
120 while (position > highThreshold)
121 position = (position + step) & tableMask; /* Low proba area */
122 } }
123
124 assert(position==0); /* Must have initialized all positions */
125 }
126
127 /* Build table */
128 { U32 u; for (u=0; u<tableSize; u++) {
129 FSE_FUNCTION_TYPE s = tableSymbol[u]; /* note : static analyzer may not understand tableSymbol is properly initialized */
130 tableU16[cumul[s]++] = (U16) (tableSize+u); /* TableU16 : sorted by symbol order; gives next state value */
131 } }
132
133 /* Build Symbol Transformation Table */
134 { unsigned total = 0;
135 unsigned s;
136 for (s=0; s<=maxSymbolValue; s++) {
137 switch (normalizedCounter[s])
138 {
139 case 0:
140 /* filling nonetheless, for compatibility with FSE_getMaxNbBits() */
141 symbolTT[s].deltaNbBits = ((tableLog+1) << 16) - (1<<tableLog);
142 break;
143
144 case -1:
145 case 1:
146 symbolTT[s].deltaNbBits = (tableLog << 16) - (1<<tableLog);
147 symbolTT[s].deltaFindState = total - 1;
148 total ++;
149 break;
150 default :
151 {
152 U32 const maxBitsOut = tableLog - BIT_highbit32 (normalizedCounter[s]-1);
153 U32 const minStatePlus = normalizedCounter[s] << maxBitsOut;
154 symbolTT[s].deltaNbBits = (maxBitsOut << 16) - minStatePlus;
155 symbolTT[s].deltaFindState = total - normalizedCounter[s];
156 total += normalizedCounter[s];
157 } } } }
158
159 #if 0 /* debug : symbol costs */
160 DEBUGLOG(5, "\n --- table statistics : ");
161 { U32 symbol;
162 for (symbol=0; symbol<=maxSymbolValue; symbol++) {
163 DEBUGLOG(5, "%3u: w=%3i, maxBits=%u, fracBits=%.2f",
164 symbol, normalizedCounter[symbol],
165 FSE_getMaxNbBits(symbolTT, symbol),
166 (double)FSE_bitCost(symbolTT, tableLog, symbol, 8) / 256);
167 }
168 }
169 #endif
170
171 return 0;
172 }
173
174
FSE_buildCTable(FSE_CTable * ct,const short * normalizedCounter,unsigned maxSymbolValue,unsigned tableLog)175 size_t FSE_buildCTable(FSE_CTable* ct, const short* normalizedCounter, unsigned maxSymbolValue, unsigned tableLog)
176 {
177 FSE_FUNCTION_TYPE tableSymbol[FSE_MAX_TABLESIZE]; /* memset() is not necessary, even if static analyzer complain about it */
178 return FSE_buildCTable_wksp(ct, normalizedCounter, maxSymbolValue, tableLog, tableSymbol, sizeof(tableSymbol));
179 }
180
181
182
183 #ifndef FSE_COMMONDEFS_ONLY
184
185
186 /*-**************************************************************
187 * FSE NCount encoding
188 ****************************************************************/
FSE_NCountWriteBound(unsigned maxSymbolValue,unsigned tableLog)189 size_t FSE_NCountWriteBound(unsigned maxSymbolValue, unsigned tableLog)
190 {
191 size_t const maxHeaderSize = (((maxSymbolValue+1) * tableLog) >> 3) + 3;
192 return maxSymbolValue ? maxHeaderSize : FSE_NCOUNTBOUND; /* maxSymbolValue==0 ? use default */
193 }
194
195 static size_t
FSE_writeNCount_generic(void * header,size_t headerBufferSize,const short * normalizedCounter,unsigned maxSymbolValue,unsigned tableLog,unsigned writeIsSafe)196 FSE_writeNCount_generic (void* header, size_t headerBufferSize,
197 const short* normalizedCounter, unsigned maxSymbolValue, unsigned tableLog,
198 unsigned writeIsSafe)
199 {
200 BYTE* const ostart = (BYTE*) header;
201 BYTE* out = ostart;
202 BYTE* const oend = ostart + headerBufferSize;
203 int nbBits;
204 const int tableSize = 1 << tableLog;
205 int remaining;
206 int threshold;
207 U32 bitStream = 0;
208 int bitCount = 0;
209 unsigned symbol = 0;
210 unsigned const alphabetSize = maxSymbolValue + 1;
211 int previousIs0 = 0;
212
213 /* Table Size */
214 bitStream += (tableLog-FSE_MIN_TABLELOG) << bitCount;
215 bitCount += 4;
216
217 /* Init */
218 remaining = tableSize+1; /* +1 for extra accuracy */
219 threshold = tableSize;
220 nbBits = tableLog+1;
221
222 while ((symbol < alphabetSize) && (remaining>1)) { /* stops at 1 */
223 if (previousIs0) {
224 unsigned start = symbol;
225 while ((symbol < alphabetSize) && !normalizedCounter[symbol]) symbol++;
226 if (symbol == alphabetSize) break; /* incorrect distribution */
227 while (symbol >= start+24) {
228 start+=24;
229 bitStream += 0xFFFFU << bitCount;
230 if ((!writeIsSafe) && (out > oend-2))
231 return ERROR(dstSize_tooSmall); /* Buffer overflow */
232 out[0] = (BYTE) bitStream;
233 out[1] = (BYTE)(bitStream>>8);
234 out+=2;
235 bitStream>>=16;
236 }
237 while (symbol >= start+3) {
238 start+=3;
239 bitStream += 3 << bitCount;
240 bitCount += 2;
241 }
242 bitStream += (symbol-start) << bitCount;
243 bitCount += 2;
244 if (bitCount>16) {
245 if ((!writeIsSafe) && (out > oend - 2))
246 return ERROR(dstSize_tooSmall); /* Buffer overflow */
247 out[0] = (BYTE)bitStream;
248 out[1] = (BYTE)(bitStream>>8);
249 out += 2;
250 bitStream >>= 16;
251 bitCount -= 16;
252 } }
253 { int count = normalizedCounter[symbol++];
254 int const max = (2*threshold-1) - remaining;
255 remaining -= count < 0 ? -count : count;
256 count++; /* +1 for extra accuracy */
257 if (count>=threshold)
258 count += max; /* [0..max[ [max..threshold[ (...) [threshold+max 2*threshold[ */
259 bitStream += count << bitCount;
260 bitCount += nbBits;
261 bitCount -= (count<max);
262 previousIs0 = (count==1);
263 if (remaining<1) return ERROR(GENERIC);
264 while (remaining<threshold) { nbBits--; threshold>>=1; }
265 }
266 if (bitCount>16) {
267 if ((!writeIsSafe) && (out > oend - 2))
268 return ERROR(dstSize_tooSmall); /* Buffer overflow */
269 out[0] = (BYTE)bitStream;
270 out[1] = (BYTE)(bitStream>>8);
271 out += 2;
272 bitStream >>= 16;
273 bitCount -= 16;
274 } }
275
276 if (remaining != 1)
277 return ERROR(GENERIC); /* incorrect normalized distribution */
278 assert(symbol <= alphabetSize);
279
280 /* flush remaining bitStream */
281 if ((!writeIsSafe) && (out > oend - 2))
282 return ERROR(dstSize_tooSmall); /* Buffer overflow */
283 out[0] = (BYTE)bitStream;
284 out[1] = (BYTE)(bitStream>>8);
285 out+= (bitCount+7) /8;
286
287 return (out-ostart);
288 }
289
290
FSE_writeNCount(void * buffer,size_t bufferSize,const short * normalizedCounter,unsigned maxSymbolValue,unsigned tableLog)291 size_t FSE_writeNCount (void* buffer, size_t bufferSize,
292 const short* normalizedCounter, unsigned maxSymbolValue, unsigned tableLog)
293 {
294 if (tableLog > FSE_MAX_TABLELOG) return ERROR(tableLog_tooLarge); /* Unsupported */
295 if (tableLog < FSE_MIN_TABLELOG) return ERROR(GENERIC); /* Unsupported */
296
297 if (bufferSize < FSE_NCountWriteBound(maxSymbolValue, tableLog))
298 return FSE_writeNCount_generic(buffer, bufferSize, normalizedCounter, maxSymbolValue, tableLog, 0);
299
300 return FSE_writeNCount_generic(buffer, bufferSize, normalizedCounter, maxSymbolValue, tableLog, 1 /* write in buffer is safe */);
301 }
302
303
304 /*-**************************************************************
305 * FSE Compression Code
306 ****************************************************************/
307
FSE_createCTable(unsigned maxSymbolValue,unsigned tableLog)308 FSE_CTable* FSE_createCTable (unsigned maxSymbolValue, unsigned tableLog)
309 {
310 size_t size;
311 if (tableLog > FSE_TABLELOG_ABSOLUTE_MAX) tableLog = FSE_TABLELOG_ABSOLUTE_MAX;
312 size = FSE_CTABLE_SIZE_U32 (tableLog, maxSymbolValue) * sizeof(U32);
313 return (FSE_CTable*)ExAllocatePoolWithTag(PagedPool, size, FSEC_ALLOC_TAG);
314 }
315
FSE_freeCTable(FSE_CTable * ct)316 void FSE_freeCTable (FSE_CTable* ct) { ExFreePool(ct); }
317
318 /* provides the minimum logSize to safely represent a distribution */
FSE_minTableLog(size_t srcSize,unsigned maxSymbolValue)319 static unsigned FSE_minTableLog(size_t srcSize, unsigned maxSymbolValue)
320 {
321 U32 minBitsSrc = BIT_highbit32((U32)(srcSize)) + 1;
322 U32 minBitsSymbols = BIT_highbit32(maxSymbolValue) + 2;
323 U32 minBits = minBitsSrc < minBitsSymbols ? minBitsSrc : minBitsSymbols;
324 assert(srcSize > 1); /* Not supported, RLE should be used instead */
325 return minBits;
326 }
327
FSE_optimalTableLog_internal(unsigned maxTableLog,size_t srcSize,unsigned maxSymbolValue,unsigned minus)328 unsigned FSE_optimalTableLog_internal(unsigned maxTableLog, size_t srcSize, unsigned maxSymbolValue, unsigned minus)
329 {
330 U32 maxBitsSrc = BIT_highbit32((U32)(srcSize - 1)) - minus;
331 U32 tableLog = maxTableLog;
332 U32 minBits = FSE_minTableLog(srcSize, maxSymbolValue);
333 assert(srcSize > 1); /* Not supported, RLE should be used instead */
334 if (tableLog==0) tableLog = FSE_DEFAULT_TABLELOG;
335 if (maxBitsSrc < tableLog) tableLog = maxBitsSrc; /* Accuracy can be reduced */
336 if (minBits > tableLog) tableLog = minBits; /* Need a minimum to safely represent all symbol values */
337 if (tableLog < FSE_MIN_TABLELOG) tableLog = FSE_MIN_TABLELOG;
338 if (tableLog > FSE_MAX_TABLELOG) tableLog = FSE_MAX_TABLELOG;
339 return tableLog;
340 }
341
FSE_optimalTableLog(unsigned maxTableLog,size_t srcSize,unsigned maxSymbolValue)342 unsigned FSE_optimalTableLog(unsigned maxTableLog, size_t srcSize, unsigned maxSymbolValue)
343 {
344 return FSE_optimalTableLog_internal(maxTableLog, srcSize, maxSymbolValue, 2);
345 }
346
347
348 /* Secondary normalization method.
349 To be used when primary method fails. */
350
FSE_normalizeM2(short * norm,U32 tableLog,const unsigned * count,size_t total,U32 maxSymbolValue)351 static size_t FSE_normalizeM2(short* norm, U32 tableLog, const unsigned* count, size_t total, U32 maxSymbolValue)
352 {
353 short const NOT_YET_ASSIGNED = -2;
354 U32 s;
355 U32 distributed = 0;
356 U32 ToDistribute;
357
358 /* Init */
359 U32 const lowThreshold = (U32)(total >> tableLog);
360 U32 lowOne = (U32)((total * 3) >> (tableLog + 1));
361
362 for (s=0; s<=maxSymbolValue; s++) {
363 if (count[s] == 0) {
364 norm[s]=0;
365 continue;
366 }
367 if (count[s] <= lowThreshold) {
368 norm[s] = -1;
369 distributed++;
370 total -= count[s];
371 continue;
372 }
373 if (count[s] <= lowOne) {
374 norm[s] = 1;
375 distributed++;
376 total -= count[s];
377 continue;
378 }
379
380 norm[s]=NOT_YET_ASSIGNED;
381 }
382 ToDistribute = (1 << tableLog) - distributed;
383
384 if (ToDistribute == 0)
385 return 0;
386
387 if ((total / ToDistribute) > lowOne) {
388 /* risk of rounding to zero */
389 lowOne = (U32)((total * 3) / (ToDistribute * 2));
390 for (s=0; s<=maxSymbolValue; s++) {
391 if ((norm[s] == NOT_YET_ASSIGNED) && (count[s] <= lowOne)) {
392 norm[s] = 1;
393 distributed++;
394 total -= count[s];
395 continue;
396 } }
397 ToDistribute = (1 << tableLog) - distributed;
398 }
399
400 if (distributed == maxSymbolValue+1) {
401 /* all values are pretty poor;
402 probably incompressible data (should have already been detected);
403 find max, then give all remaining points to max */
404 U32 maxV = 0, maxC = 0;
405 for (s=0; s<=maxSymbolValue; s++)
406 if (count[s] > maxC) { maxV=s; maxC=count[s]; }
407 norm[maxV] += (short)ToDistribute;
408 return 0;
409 }
410
411 if (total == 0) {
412 /* all of the symbols were low enough for the lowOne or lowThreshold */
413 for (s=0; ToDistribute > 0; s = (s+1)%(maxSymbolValue+1))
414 if (norm[s] > 0) { ToDistribute--; norm[s]++; }
415 return 0;
416 }
417
418 { U64 const vStepLog = 62 - tableLog;
419 U64 const mid = (1ULL << (vStepLog-1)) - 1;
420 U64 const rStep = ((((U64)1<<vStepLog) * ToDistribute) + mid) / total; /* scale on remaining */
421 U64 tmpTotal = mid;
422 for (s=0; s<=maxSymbolValue; s++) {
423 if (norm[s]==NOT_YET_ASSIGNED) {
424 U64 const end = tmpTotal + (count[s] * rStep);
425 U32 const sStart = (U32)(tmpTotal >> vStepLog);
426 U32 const sEnd = (U32)(end >> vStepLog);
427 U32 const weight = sEnd - sStart;
428 if (weight < 1)
429 return ERROR(GENERIC);
430 norm[s] = (short)weight;
431 tmpTotal = end;
432 } } }
433
434 return 0;
435 }
436
437
FSE_normalizeCount(short * normalizedCounter,unsigned tableLog,const unsigned * count,size_t total,unsigned maxSymbolValue)438 size_t FSE_normalizeCount (short* normalizedCounter, unsigned tableLog,
439 const unsigned* count, size_t total,
440 unsigned maxSymbolValue)
441 {
442 /* Sanity checks */
443 if (tableLog==0) tableLog = FSE_DEFAULT_TABLELOG;
444 if (tableLog < FSE_MIN_TABLELOG) return ERROR(GENERIC); /* Unsupported size */
445 if (tableLog > FSE_MAX_TABLELOG) return ERROR(tableLog_tooLarge); /* Unsupported size */
446 if (tableLog < FSE_minTableLog(total, maxSymbolValue)) return ERROR(GENERIC); /* Too small tableLog, compression potentially impossible */
447
448 { static U32 const rtbTable[] = { 0, 473195, 504333, 520860, 550000, 700000, 750000, 830000 };
449 U64 const scale = 62 - tableLog;
450 U64 const step = ((U64)1<<62) / total; /* <== here, one division ! */
451 U64 const vStep = 1ULL<<(scale-20);
452 int stillToDistribute = 1<<tableLog;
453 unsigned s;
454 unsigned largest=0;
455 short largestP=0;
456 U32 lowThreshold = (U32)(total >> tableLog);
457
458 for (s=0; s<=maxSymbolValue; s++) {
459 if (count[s] == total) return 0; /* rle special case */
460 if (count[s] == 0) { normalizedCounter[s]=0; continue; }
461 if (count[s] <= lowThreshold) {
462 normalizedCounter[s] = -1;
463 stillToDistribute--;
464 } else {
465 short proba = (short)((count[s]*step) >> scale);
466 if (proba<8) {
467 U64 restToBeat = vStep * rtbTable[proba];
468 proba += (count[s]*step) - ((U64)proba<<scale) > restToBeat;
469 }
470 if (proba > largestP) { largestP=proba; largest=s; }
471 normalizedCounter[s] = proba;
472 stillToDistribute -= proba;
473 } }
474 if (-stillToDistribute >= (normalizedCounter[largest] >> 1)) {
475 /* corner case, need another normalization method */
476 size_t const errorCode = FSE_normalizeM2(normalizedCounter, tableLog, count, total, maxSymbolValue);
477 if (FSE_isError(errorCode)) return errorCode;
478 }
479 else normalizedCounter[largest] += (short)stillToDistribute;
480 }
481
482 #if 0
483 { /* Print Table (debug) */
484 U32 s;
485 U32 nTotal = 0;
486 for (s=0; s<=maxSymbolValue; s++)
487 RAWLOG(2, "%3i: %4i \n", s, normalizedCounter[s]);
488 for (s=0; s<=maxSymbolValue; s++)
489 nTotal += abs(normalizedCounter[s]);
490 if (nTotal != (1U<<tableLog))
491 RAWLOG(2, "Warning !!! Total == %u != %u !!!", nTotal, 1U<<tableLog);
492 getchar();
493 }
494 #endif
495
496 return tableLog;
497 }
498
499
500 /* fake FSE_CTable, for raw (uncompressed) input */
FSE_buildCTable_raw(FSE_CTable * ct,unsigned nbBits)501 size_t FSE_buildCTable_raw (FSE_CTable* ct, unsigned nbBits)
502 {
503 const unsigned tableSize = 1 << nbBits;
504 const unsigned tableMask = tableSize - 1;
505 const unsigned maxSymbolValue = tableMask;
506 void* const ptr = ct;
507 U16* const tableU16 = ( (U16*) ptr) + 2;
508 void* const FSCT = ((U32*)ptr) + 1 /* header */ + (tableSize>>1); /* assumption : tableLog >= 1 */
509 FSE_symbolCompressionTransform* const symbolTT = (FSE_symbolCompressionTransform*) (FSCT);
510 unsigned s;
511
512 /* Sanity checks */
513 if (nbBits < 1) return ERROR(GENERIC); /* min size */
514
515 /* header */
516 tableU16[-2] = (U16) nbBits;
517 tableU16[-1] = (U16) maxSymbolValue;
518
519 /* Build table */
520 for (s=0; s<tableSize; s++)
521 tableU16[s] = (U16)(tableSize + s);
522
523 /* Build Symbol Transformation Table */
524 { const U32 deltaNbBits = (nbBits << 16) - (1 << nbBits);
525 for (s=0; s<=maxSymbolValue; s++) {
526 symbolTT[s].deltaNbBits = deltaNbBits;
527 symbolTT[s].deltaFindState = s-1;
528 } }
529
530 return 0;
531 }
532
533 /* fake FSE_CTable, for rle input (always same symbol) */
FSE_buildCTable_rle(FSE_CTable * ct,BYTE symbolValue)534 size_t FSE_buildCTable_rle (FSE_CTable* ct, BYTE symbolValue)
535 {
536 void* ptr = ct;
537 U16* tableU16 = ( (U16*) ptr) + 2;
538 void* FSCTptr = (U32*)ptr + 2;
539 FSE_symbolCompressionTransform* symbolTT = (FSE_symbolCompressionTransform*) FSCTptr;
540
541 /* header */
542 tableU16[-2] = (U16) 0;
543 tableU16[-1] = (U16) symbolValue;
544
545 /* Build table */
546 tableU16[0] = 0;
547 tableU16[1] = 0; /* just in case */
548
549 /* Build Symbol Transformation Table */
550 symbolTT[symbolValue].deltaNbBits = 0;
551 symbolTT[symbolValue].deltaFindState = 0;
552
553 return 0;
554 }
555
556
FSE_compress_usingCTable_generic(void * dst,size_t dstSize,const void * src,size_t srcSize,const FSE_CTable * ct,const unsigned fast)557 static size_t FSE_compress_usingCTable_generic (void* dst, size_t dstSize,
558 const void* src, size_t srcSize,
559 const FSE_CTable* ct, const unsigned fast)
560 {
561 const BYTE* const istart = (const BYTE*) src;
562 const BYTE* const iend = istart + srcSize;
563 const BYTE* ip=iend;
564
565 BIT_CStream_t bitC;
566 FSE_CState_t CState1, CState2;
567
568 /* init */
569 if (srcSize <= 2) return 0;
570 { size_t const initError = BIT_initCStream(&bitC, dst, dstSize);
571 if (FSE_isError(initError)) return 0; /* not enough space available to write a bitstream */ }
572
573 #define FSE_FLUSHBITS(s) (fast ? BIT_flushBitsFast(s) : BIT_flushBits(s))
574
575 if (srcSize & 1) {
576 FSE_initCState2(&CState1, ct, *--ip);
577 FSE_initCState2(&CState2, ct, *--ip);
578 FSE_encodeSymbol(&bitC, &CState1, *--ip);
579 FSE_FLUSHBITS(&bitC);
580 } else {
581 FSE_initCState2(&CState2, ct, *--ip);
582 FSE_initCState2(&CState1, ct, *--ip);
583 }
584
585 /* join to mod 4 */
586 srcSize -= 2;
587 if ((sizeof(bitC.bitContainer)*8 > FSE_MAX_TABLELOG*4+7 ) && (srcSize & 2)) { /* test bit 2 */
588 FSE_encodeSymbol(&bitC, &CState2, *--ip);
589 FSE_encodeSymbol(&bitC, &CState1, *--ip);
590 FSE_FLUSHBITS(&bitC);
591 }
592
593 /* 2 or 4 encoding per loop */
594 while ( ip>istart ) {
595
596 FSE_encodeSymbol(&bitC, &CState2, *--ip);
597
598 if (sizeof(bitC.bitContainer)*8 < FSE_MAX_TABLELOG*2+7 ) /* this test must be static */
599 FSE_FLUSHBITS(&bitC);
600
601 FSE_encodeSymbol(&bitC, &CState1, *--ip);
602
603 if (sizeof(bitC.bitContainer)*8 > FSE_MAX_TABLELOG*4+7 ) { /* this test must be static */
604 FSE_encodeSymbol(&bitC, &CState2, *--ip);
605 FSE_encodeSymbol(&bitC, &CState1, *--ip);
606 }
607
608 FSE_FLUSHBITS(&bitC);
609 }
610
611 FSE_flushCState(&bitC, &CState2);
612 FSE_flushCState(&bitC, &CState1);
613 return BIT_closeCStream(&bitC);
614 }
615
FSE_compress_usingCTable(void * dst,size_t dstSize,const void * src,size_t srcSize,const FSE_CTable * ct)616 size_t FSE_compress_usingCTable (void* dst, size_t dstSize,
617 const void* src, size_t srcSize,
618 const FSE_CTable* ct)
619 {
620 unsigned const fast = (dstSize >= FSE_BLOCKBOUND(srcSize));
621
622 if (fast)
623 return FSE_compress_usingCTable_generic(dst, dstSize, src, srcSize, ct, 1);
624 else
625 return FSE_compress_usingCTable_generic(dst, dstSize, src, srcSize, ct, 0);
626 }
627
628
FSE_compressBound(size_t size)629 size_t FSE_compressBound(size_t size) { return FSE_COMPRESSBOUND(size); }
630
631 /* FSE_compress_wksp() :
632 * Same as FSE_compress2(), but using an externally allocated scratch buffer (`workSpace`).
633 * `wkspSize` size must be `(1<<tableLog)`.
634 */
FSE_compress_wksp(void * dst,size_t dstSize,const void * src,size_t srcSize,unsigned maxSymbolValue,unsigned tableLog,void * workSpace,size_t wkspSize)635 size_t FSE_compress_wksp (void* dst, size_t dstSize, const void* src, size_t srcSize, unsigned maxSymbolValue, unsigned tableLog, void* workSpace, size_t wkspSize)
636 {
637 BYTE* const ostart = (BYTE*) dst;
638 BYTE* op = ostart;
639 BYTE* const oend = ostart + dstSize;
640
641 unsigned count[FSE_MAX_SYMBOL_VALUE+1];
642 S16 norm[FSE_MAX_SYMBOL_VALUE+1];
643 FSE_CTable* CTable = (FSE_CTable*)workSpace;
644 size_t const CTableSize = FSE_CTABLE_SIZE_U32(tableLog, maxSymbolValue);
645 void* scratchBuffer = (void*)(CTable + CTableSize);
646 size_t const scratchBufferSize = wkspSize - (CTableSize * sizeof(FSE_CTable));
647
648 /* init conditions */
649 if (wkspSize < FSE_WKSP_SIZE_U32(tableLog, maxSymbolValue)) return ERROR(tableLog_tooLarge);
650 if (srcSize <= 1) return 0; /* Not compressible */
651 if (!maxSymbolValue) maxSymbolValue = FSE_MAX_SYMBOL_VALUE;
652 if (!tableLog) tableLog = FSE_DEFAULT_TABLELOG;
653
654 /* Scan input and build symbol stats */
655 { CHECK_V_F(maxCount, HIST_count_wksp(count, &maxSymbolValue, src, srcSize, scratchBuffer, scratchBufferSize) );
656 if (maxCount == srcSize) return 1; /* only a single symbol in src : rle */
657 if (maxCount == 1) return 0; /* each symbol present maximum once => not compressible */
658 if (maxCount < (srcSize >> 7)) return 0; /* Heuristic : not compressible enough */
659 }
660
661 tableLog = FSE_optimalTableLog(tableLog, srcSize, maxSymbolValue);
662 CHECK_F( FSE_normalizeCount(norm, tableLog, count, srcSize, maxSymbolValue) );
663
664 /* Write table description header */
665 { CHECK_V_F(nc_err, FSE_writeNCount(op, oend-op, norm, maxSymbolValue, tableLog) );
666 op += nc_err;
667 }
668
669 /* Compress */
670 CHECK_F( FSE_buildCTable_wksp(CTable, norm, maxSymbolValue, tableLog, scratchBuffer, scratchBufferSize) );
671 { CHECK_V_F(cSize, FSE_compress_usingCTable(op, oend - op, src, srcSize, CTable) );
672 if (cSize == 0) return 0; /* not enough space for compressed data */
673 op += cSize;
674 }
675
676 /* check compressibility */
677 if ( (size_t)(op-ostart) >= srcSize-1 ) return 0;
678
679 return op-ostart;
680 }
681
682 typedef struct {
683 FSE_CTable CTable_max[FSE_CTABLE_SIZE_U32(FSE_MAX_TABLELOG, FSE_MAX_SYMBOL_VALUE)];
684 BYTE scratchBuffer[1 << FSE_MAX_TABLELOG];
685 } fseWkspMax_t;
686
FSE_compress2(void * dst,size_t dstCapacity,const void * src,size_t srcSize,unsigned maxSymbolValue,unsigned tableLog)687 size_t FSE_compress2 (void* dst, size_t dstCapacity, const void* src, size_t srcSize, unsigned maxSymbolValue, unsigned tableLog)
688 {
689 fseWkspMax_t scratchBuffer;
690 DEBUG_STATIC_ASSERT(sizeof(scratchBuffer) >= FSE_WKSP_SIZE_U32(FSE_MAX_TABLELOG, FSE_MAX_SYMBOL_VALUE)); /* compilation failures here means scratchBuffer is not large enough */
691 if (tableLog > FSE_MAX_TABLELOG) return ERROR(tableLog_tooLarge);
692 return FSE_compress_wksp(dst, dstCapacity, src, srcSize, maxSymbolValue, tableLog, &scratchBuffer, sizeof(scratchBuffer));
693 }
694
FSE_compress(void * dst,size_t dstCapacity,const void * src,size_t srcSize)695 size_t FSE_compress (void* dst, size_t dstCapacity, const void* src, size_t srcSize)
696 {
697 return FSE_compress2(dst, dstCapacity, src, srcSize, FSE_MAX_SYMBOL_VALUE, FSE_DEFAULT_TABLELOG);
698 }
699
700
701 #endif /* FSE_COMMONDEFS_ONLY */
702