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zpool/zfs: restore -V & --version options
[zfs.git] / module / zstd / lib / compress / zstd_compress_superblock.c
blob77d05d394c395408d3545ba644c01c21b2320655
1 /*
2 * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc.
3 * All rights reserved.
4 *
5 * This source code is licensed under both the BSD-style license (found in the
6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
7 * in the COPYING file in the root directory of this source tree).
8 * You may select, at your option, one of the above-listed licenses.
9 */
10
11 /*-*************************************
12 * Dependencies
13 ***************************************/
14 #include "zstd_compress_superblock.h"
15
16 #include "../common/zstd_internal.h" /* ZSTD_getSequenceLength */
17 #include "hist.h" /* HIST_countFast_wksp */
18 #include "zstd_compress_internal.h"
19 #include "zstd_compress_sequences.h"
20 #include "zstd_compress_literals.h"
21
22 /*-*************************************
23 * Superblock entropy buffer structs
24 ***************************************/
25 /** ZSTD_hufCTablesMetadata_t :
26 * Stores Literals Block Type for a super-block in hType, and
27 * huffman tree description in hufDesBuffer.
28 * hufDesSize refers to the size of huffman tree description in bytes.
29 * This metadata is populated in ZSTD_buildSuperBlockEntropy_literal() */
30 typedef struct {
31 symbolEncodingType_e hType;
32 BYTE hufDesBuffer[500]; /* TODO give name to this value */
33 size_t hufDesSize;
34 } ZSTD_hufCTablesMetadata_t;
35
36 /** ZSTD_fseCTablesMetadata_t :
37 * Stores symbol compression modes for a super-block in {ll, ol, ml}Type, and
38 * fse tables in fseTablesBuffer.
39 * fseTablesSize refers to the size of fse tables in bytes.
40 * This metadata is populated in ZSTD_buildSuperBlockEntropy_sequences() */
41 typedef struct {
42 symbolEncodingType_e llType;
43 symbolEncodingType_e ofType;
44 symbolEncodingType_e mlType;
45 BYTE fseTablesBuffer[500]; /* TODO give name to this value */
46 size_t fseTablesSize;
47 size_t lastCountSize; /* This is to account for bug in 1.3.4. More detail in ZSTD_compressSubBlock_sequences() */
48 } ZSTD_fseCTablesMetadata_t;
49
50 typedef struct {
51 ZSTD_hufCTablesMetadata_t hufMetadata;
52 ZSTD_fseCTablesMetadata_t fseMetadata;
53 } ZSTD_entropyCTablesMetadata_t;
54
55
56 /** ZSTD_buildSuperBlockEntropy_literal() :
57 * Builds entropy for the super-block literals.
58 * Stores literals block type (raw, rle, compressed, repeat) and
59 * huffman description table to hufMetadata.
60 * @return : size of huffman description table or error code */
61 static size_t ZSTD_buildSuperBlockEntropy_literal(void* const src, size_t srcSize,
62 const ZSTD_hufCTables_t* prevHuf,
63 ZSTD_hufCTables_t* nextHuf,
64 ZSTD_hufCTablesMetadata_t* hufMetadata,
65 const int disableLiteralsCompression,
66 void* workspace, size_t wkspSize)
67 {
68 BYTE* const wkspStart = (BYTE*)workspace;
69 BYTE* const wkspEnd = wkspStart + wkspSize;
70 BYTE* const countWkspStart = wkspStart;
71 unsigned* const countWksp = (unsigned*)workspace;
72 const size_t countWkspSize = (HUF_SYMBOLVALUE_MAX + 1) * sizeof(unsigned);
73 BYTE* const nodeWksp = countWkspStart + countWkspSize;
74 const size_t nodeWkspSize = wkspEnd-nodeWksp;
75 unsigned maxSymbolValue = 255;
76 unsigned huffLog = HUF_TABLELOG_DEFAULT;
77 HUF_repeat repeat = prevHuf->repeatMode;
78
79 DEBUGLOG(5, "ZSTD_buildSuperBlockEntropy_literal (srcSize=%zu)", srcSize);
80
81 /* Prepare nextEntropy assuming reusing the existing table */
82 memcpy(nextHuf, prevHuf, sizeof(*prevHuf));
83
84 if (disableLiteralsCompression) {
85 DEBUGLOG(5, "set_basic - disabled");
86 hufMetadata->hType = set_basic;
87 return 0;
88 }
89
90 /* small ? don't even attempt compression (speed opt) */
91 # define COMPRESS_LITERALS_SIZE_MIN 63
92 { size_t const minLitSize = (prevHuf->repeatMode == HUF_repeat_valid) ? 6 : COMPRESS_LITERALS_SIZE_MIN;
93 if (srcSize <= minLitSize) {
94 DEBUGLOG(5, "set_basic - too small");
95 hufMetadata->hType = set_basic;
96 return 0;
97 }
98 }
99
100 /* Scan input and build symbol stats */
101 { size_t const largest = HIST_count_wksp (countWksp, &maxSymbolValue, (const BYTE*)src, srcSize, workspace, wkspSize);
102 FORWARD_IF_ERROR(largest, "HIST_count_wksp failed");
103 if (largest == srcSize) {
104 DEBUGLOG(5, "set_rle");
105 hufMetadata->hType = set_rle;
106 return 0;
107 }
108 if (largest <= (srcSize >> 7)+4) {
109 DEBUGLOG(5, "set_basic - no gain");
110 hufMetadata->hType = set_basic;
111 return 0;
112 }
113 }
114
115 /* Validate the previous Huffman table */
116 if (repeat == HUF_repeat_check && !HUF_validateCTable((HUF_CElt const*)prevHuf->CTable, countWksp, maxSymbolValue)) {
117 repeat = HUF_repeat_none;
118 }
119
120 /* Build Huffman Tree */
121 memset(nextHuf->CTable, 0, sizeof(nextHuf->CTable));
122 huffLog = HUF_optimalTableLog(huffLog, srcSize, maxSymbolValue);
123 { size_t const maxBits = HUF_buildCTable_wksp((HUF_CElt*)nextHuf->CTable, countWksp,
124 maxSymbolValue, huffLog,
125 nodeWksp, nodeWkspSize);
126 FORWARD_IF_ERROR(maxBits, "HUF_buildCTable_wksp");
127 huffLog = (U32)maxBits;
128 { /* Build and write the CTable */
129 size_t const newCSize = HUF_estimateCompressedSize(
130 (HUF_CElt*)nextHuf->CTable, countWksp, maxSymbolValue);
131 size_t const hSize = HUF_writeCTable(
132 hufMetadata->hufDesBuffer, sizeof(hufMetadata->hufDesBuffer),
133 (HUF_CElt*)nextHuf->CTable, maxSymbolValue, huffLog);
134 /* Check against repeating the previous CTable */
135 if (repeat != HUF_repeat_none) {
136 size_t const oldCSize = HUF_estimateCompressedSize(
137 (HUF_CElt const*)prevHuf->CTable, countWksp, maxSymbolValue);
138 if (oldCSize < srcSize && (oldCSize <= hSize + newCSize || hSize + 12 >= srcSize)) {
139 DEBUGLOG(5, "set_repeat - smaller");
140 memcpy(nextHuf, prevHuf, sizeof(*prevHuf));
141 hufMetadata->hType = set_repeat;
142 return 0;
143 }
144 }
145 if (newCSize + hSize >= srcSize) {
146 DEBUGLOG(5, "set_basic - no gains");
147 memcpy(nextHuf, prevHuf, sizeof(*prevHuf));
148 hufMetadata->hType = set_basic;
149 return 0;
150 }
151 DEBUGLOG(5, "set_compressed (hSize=%u)", (U32)hSize);
152 hufMetadata->hType = set_compressed;
153 nextHuf->repeatMode = HUF_repeat_check;
154 return hSize;
155 }
156 }
157 }
158
159 /** ZSTD_buildSuperBlockEntropy_sequences() :
160 * Builds entropy for the super-block sequences.
161 * Stores symbol compression modes and fse table to fseMetadata.
162 * @return : size of fse tables or error code */
163 static size_t ZSTD_buildSuperBlockEntropy_sequences(seqStore_t* seqStorePtr,
164 const ZSTD_fseCTables_t* prevEntropy,
165 ZSTD_fseCTables_t* nextEntropy,
166 const ZSTD_CCtx_params* cctxParams,
167 ZSTD_fseCTablesMetadata_t* fseMetadata,
168 void* workspace, size_t wkspSize)
169 {
170 BYTE* const wkspStart = (BYTE*)workspace;
171 BYTE* const wkspEnd = wkspStart + wkspSize;
172 BYTE* const countWkspStart = wkspStart;
173 unsigned* const countWksp = (unsigned*)workspace;
174 const size_t countWkspSize = (MaxSeq + 1) * sizeof(unsigned);
175 BYTE* const cTableWksp = countWkspStart + countWkspSize;
176 const size_t cTableWkspSize = wkspEnd-cTableWksp;
177 ZSTD_strategy const strategy = cctxParams->cParams.strategy;
178 FSE_CTable* CTable_LitLength = nextEntropy->litlengthCTable;
179 FSE_CTable* CTable_OffsetBits = nextEntropy->offcodeCTable;
180 FSE_CTable* CTable_MatchLength = nextEntropy->matchlengthCTable;
181 const BYTE* const ofCodeTable = seqStorePtr->ofCode;
182 const BYTE* const llCodeTable = seqStorePtr->llCode;
183 const BYTE* const mlCodeTable = seqStorePtr->mlCode;
184 size_t const nbSeq = seqStorePtr->sequences - seqStorePtr->sequencesStart;
185 BYTE* const ostart = fseMetadata->fseTablesBuffer;
186 BYTE* const oend = ostart + sizeof(fseMetadata->fseTablesBuffer);
187 BYTE* op = ostart;
188
189 assert(cTableWkspSize >= (1 << MaxFSELog) * sizeof(FSE_FUNCTION_TYPE));
190 DEBUGLOG(5, "ZSTD_buildSuperBlockEntropy_sequences (nbSeq=%zu)", nbSeq);
191 memset(workspace, 0, wkspSize);
192
193 fseMetadata->lastCountSize = 0;
194 /* convert length/distances into codes */
195 ZSTD_seqToCodes(seqStorePtr);
196 /* build CTable for Literal Lengths */
197 { U32 LLtype;
198 unsigned max = MaxLL;
199 size_t const mostFrequent = HIST_countFast_wksp(countWksp, &max, llCodeTable, nbSeq, workspace, wkspSize); /* can't fail */
200 DEBUGLOG(5, "Building LL table");
201 nextEntropy->litlength_repeatMode = prevEntropy->litlength_repeatMode;
202 LLtype = ZSTD_selectEncodingType(&nextEntropy->litlength_repeatMode,
203 countWksp, max, mostFrequent, nbSeq,
204 LLFSELog, prevEntropy->litlengthCTable,
205 LL_defaultNorm, LL_defaultNormLog,
206 ZSTD_defaultAllowed, strategy);
207 assert(set_basic < set_compressed && set_rle < set_compressed);
208 assert(!(LLtype < set_compressed && nextEntropy->litlength_repeatMode != FSE_repeat_none)); /* We don't copy tables */
209 { size_t const countSize = ZSTD_buildCTable(op, oend - op, CTable_LitLength, LLFSELog, (symbolEncodingType_e)LLtype,
210 countWksp, max, llCodeTable, nbSeq, LL_defaultNorm, LL_defaultNormLog, MaxLL,
211 prevEntropy->litlengthCTable, sizeof(prevEntropy->litlengthCTable),
212 cTableWksp, cTableWkspSize);
213 FORWARD_IF_ERROR(countSize, "ZSTD_buildCTable for LitLens failed");
214 if (LLtype == set_compressed)
215 fseMetadata->lastCountSize = countSize;
216 op += countSize;
217 fseMetadata->llType = (symbolEncodingType_e) LLtype;
218 } }
219 /* build CTable for Offsets */
220 { U32 Offtype;
221 unsigned max = MaxOff;
222 size_t const mostFrequent = HIST_countFast_wksp(countWksp, &max, ofCodeTable, nbSeq, workspace, wkspSize); /* can't fail */
223 /* We can only use the basic table if max <= DefaultMaxOff, otherwise the offsets are too large */
224 ZSTD_defaultPolicy_e const defaultPolicy = (max <= DefaultMaxOff) ? ZSTD_defaultAllowed : ZSTD_defaultDisallowed;
225 DEBUGLOG(5, "Building OF table");
226 nextEntropy->offcode_repeatMode = prevEntropy->offcode_repeatMode;
227 Offtype = ZSTD_selectEncodingType(&nextEntropy->offcode_repeatMode,
228 countWksp, max, mostFrequent, nbSeq,
229 OffFSELog, prevEntropy->offcodeCTable,
230 OF_defaultNorm, OF_defaultNormLog,
231 defaultPolicy, strategy);
232 assert(!(Offtype < set_compressed && nextEntropy->offcode_repeatMode != FSE_repeat_none)); /* We don't copy tables */
233 { size_t const countSize = ZSTD_buildCTable(op, oend - op, CTable_OffsetBits, OffFSELog, (symbolEncodingType_e)Offtype,
234 countWksp, max, ofCodeTable, nbSeq, OF_defaultNorm, OF_defaultNormLog, DefaultMaxOff,
235 prevEntropy->offcodeCTable, sizeof(prevEntropy->offcodeCTable),
236 cTableWksp, cTableWkspSize);
237 FORWARD_IF_ERROR(countSize, "ZSTD_buildCTable for Offsets failed");
238 if (Offtype == set_compressed)
239 fseMetadata->lastCountSize = countSize;
240 op += countSize;
241 fseMetadata->ofType = (symbolEncodingType_e) Offtype;
242 } }
243 /* build CTable for MatchLengths */
244 { U32 MLtype;
245 unsigned max = MaxML;
246 size_t const mostFrequent = HIST_countFast_wksp(countWksp, &max, mlCodeTable, nbSeq, workspace, wkspSize); /* can't fail */
247 DEBUGLOG(5, "Building ML table (remaining space : %i)", (int)(oend-op));
248 nextEntropy->matchlength_repeatMode = prevEntropy->matchlength_repeatMode;
249 MLtype = ZSTD_selectEncodingType(&nextEntropy->matchlength_repeatMode,
250 countWksp, max, mostFrequent, nbSeq,
251 MLFSELog, prevEntropy->matchlengthCTable,
252 ML_defaultNorm, ML_defaultNormLog,
253 ZSTD_defaultAllowed, strategy);
254 assert(!(MLtype < set_compressed && nextEntropy->matchlength_repeatMode != FSE_repeat_none)); /* We don't copy tables */
255 { size_t const countSize = ZSTD_buildCTable(op, oend - op, CTable_MatchLength, MLFSELog, (symbolEncodingType_e)MLtype,
256 countWksp, max, mlCodeTable, nbSeq, ML_defaultNorm, ML_defaultNormLog, MaxML,
257 prevEntropy->matchlengthCTable, sizeof(prevEntropy->matchlengthCTable),
258 cTableWksp, cTableWkspSize);
259 FORWARD_IF_ERROR(countSize, "ZSTD_buildCTable for MatchLengths failed");
260 if (MLtype == set_compressed)
261 fseMetadata->lastCountSize = countSize;
262 op += countSize;
263 fseMetadata->mlType = (symbolEncodingType_e) MLtype;
264 } }
265 assert((size_t) (op-ostart) <= sizeof(fseMetadata->fseTablesBuffer));
266 return op-ostart;
267 }
268
269
270 /** ZSTD_buildSuperBlockEntropy() :
271 * Builds entropy for the super-block.
272 * @return : 0 on success or error code */
273 static size_t
274 ZSTD_buildSuperBlockEntropy(seqStore_t* seqStorePtr,
275 const ZSTD_entropyCTables_t* prevEntropy,
276 ZSTD_entropyCTables_t* nextEntropy,
277 const ZSTD_CCtx_params* cctxParams,
278 ZSTD_entropyCTablesMetadata_t* entropyMetadata,
279 void* workspace, size_t wkspSize)
280 {
281 size_t const litSize = seqStorePtr->lit - seqStorePtr->litStart;
282 DEBUGLOG(5, "ZSTD_buildSuperBlockEntropy");
283 entropyMetadata->hufMetadata.hufDesSize =
284 ZSTD_buildSuperBlockEntropy_literal(seqStorePtr->litStart, litSize,
285 &prevEntropy->huf, &nextEntropy->huf,
286 &entropyMetadata->hufMetadata,
287 ZSTD_disableLiteralsCompression(cctxParams),
288 workspace, wkspSize);
289 FORWARD_IF_ERROR(entropyMetadata->hufMetadata.hufDesSize, "ZSTD_buildSuperBlockEntropy_literal failed");
290 entropyMetadata->fseMetadata.fseTablesSize =
291 ZSTD_buildSuperBlockEntropy_sequences(seqStorePtr,
292 &prevEntropy->fse, &nextEntropy->fse,
293 cctxParams,
294 &entropyMetadata->fseMetadata,
295 workspace, wkspSize);
296 FORWARD_IF_ERROR(entropyMetadata->fseMetadata.fseTablesSize, "ZSTD_buildSuperBlockEntropy_sequences failed");
297 return 0;
298 }
299
300 /** ZSTD_compressSubBlock_literal() :
301 * Compresses literals section for a sub-block.
302 * When we have to write the Huffman table we will sometimes choose a header
303 * size larger than necessary. This is because we have to pick the header size
304 * before we know the table size + compressed size, so we have a bound on the
305 * table size. If we guessed incorrectly, we fall back to uncompressed literals.
306 *
307 * We write the header when writeEntropy=1 and set entropyWrriten=1 when we succeeded
308 * in writing the header, otherwise it is set to 0.
309 *
310 * hufMetadata->hType has literals block type info.
311 * If it is set_basic, all sub-blocks literals section will be Raw_Literals_Block.
312 * If it is set_rle, all sub-blocks literals section will be RLE_Literals_Block.
313 * If it is set_compressed, first sub-block's literals section will be Compressed_Literals_Block
314 * If it is set_compressed, first sub-block's literals section will be Treeless_Literals_Block
315 * and the following sub-blocks' literals sections will be Treeless_Literals_Block.
316 * @return : compressed size of literals section of a sub-block
317 * Or 0 if it unable to compress.
318 * Or error code */
319 static size_t ZSTD_compressSubBlock_literal(const HUF_CElt* hufTable,
320 const ZSTD_hufCTablesMetadata_t* hufMetadata,
321 const BYTE* literals, size_t litSize,
322 void* dst, size_t dstSize,
323 const int bmi2, int writeEntropy, int* entropyWritten)
324 {
325 size_t const header = writeEntropy ? 200 : 0;
326 size_t const lhSize = 3 + (litSize >= (1 KB - header)) + (litSize >= (16 KB - header));
327 BYTE* const ostart = (BYTE*)dst;
328 BYTE* const oend = ostart + dstSize;
329 BYTE* op = ostart + lhSize;
330 U32 const singleStream = lhSize == 3;
331 symbolEncodingType_e hType = writeEntropy ? hufMetadata->hType : set_repeat;
332 size_t cLitSize = 0;
333
334 (void)bmi2; /* TODO bmi2... */
335
336 DEBUGLOG(5, "ZSTD_compressSubBlock_literal (litSize=%zu, lhSize=%zu, writeEntropy=%d)", litSize, lhSize, writeEntropy);
337
338 *entropyWritten = 0;
339 if (litSize == 0 || hufMetadata->hType == set_basic) {
340 DEBUGLOG(5, "ZSTD_compressSubBlock_literal using raw literal");
341 return ZSTD_noCompressLiterals(dst, dstSize, literals, litSize);
342 } else if (hufMetadata->hType == set_rle) {
343 DEBUGLOG(5, "ZSTD_compressSubBlock_literal using rle literal");
344 return ZSTD_compressRleLiteralsBlock(dst, dstSize, literals, litSize);
345 }
346
347 assert(litSize > 0);
348 assert(hufMetadata->hType == set_compressed || hufMetadata->hType == set_repeat);
349
350 if (writeEntropy && hufMetadata->hType == set_compressed) {
351 memcpy(op, hufMetadata->hufDesBuffer, hufMetadata->hufDesSize);
352 op += hufMetadata->hufDesSize;
353 cLitSize += hufMetadata->hufDesSize;
354 DEBUGLOG(5, "ZSTD_compressSubBlock_literal (hSize=%zu)", hufMetadata->hufDesSize);
355 }
356
357 /* TODO bmi2 */
358 { const size_t cSize = singleStream ? HUF_compress1X_usingCTable(op, oend-op, literals, litSize, hufTable)
359 : HUF_compress4X_usingCTable(op, oend-op, literals, litSize, hufTable);
360 op += cSize;
361 cLitSize += cSize;
362 if (cSize == 0 || ERR_isError(cSize)) {
363 DEBUGLOG(5, "Failed to write entropy tables %s", ZSTD_getErrorName(cSize));
364 return 0;
365 }
366 /* If we expand and we aren't writing a header then emit uncompressed */
367 if (!writeEntropy && cLitSize >= litSize) {
368 DEBUGLOG(5, "ZSTD_compressSubBlock_literal using raw literal because uncompressible");
369 return ZSTD_noCompressLiterals(dst, dstSize, literals, litSize);
370 }
371 /* If we are writing headers then allow expansion that doesn't change our header size. */
372 if (lhSize < (size_t)(3 + (cLitSize >= 1 KB) + (cLitSize >= 16 KB))) {
373 assert(cLitSize > litSize);
374 DEBUGLOG(5, "Literals expanded beyond allowed header size");
375 return ZSTD_noCompressLiterals(dst, dstSize, literals, litSize);
376 }
377 DEBUGLOG(5, "ZSTD_compressSubBlock_literal (cSize=%zu)", cSize);
378 }
379
380 /* Build header */
381 switch(lhSize)
382 {
383 case 3: /* 2 - 2 - 10 - 10 */
384 { U32 const lhc = hType + ((!singleStream) << 2) + ((U32)litSize<<4) + ((U32)cLitSize<<14);
385 MEM_writeLE24(ostart, lhc);
386 break;
387 }
388 case 4: /* 2 - 2 - 14 - 14 */
389 { U32 const lhc = hType + (2 << 2) + ((U32)litSize<<4) + ((U32)cLitSize<<18);
390 MEM_writeLE32(ostart, lhc);
391 break;
392 }
393 case 5: /* 2 - 2 - 18 - 18 */
394 { U32 const lhc = hType + (3 << 2) + ((U32)litSize<<4) + ((U32)cLitSize<<22);
395 MEM_writeLE32(ostart, lhc);
396 ostart[4] = (BYTE)(cLitSize >> 10);
397 break;
398 }
399 default: /* not possible : lhSize is {3,4,5} */
400 assert(0);
401 }
402 *entropyWritten = 1;
403 DEBUGLOG(5, "Compressed literals: %u -> %u", (U32)litSize, (U32)(op-ostart));
404 return op-ostart;
405 }
406
407 static size_t ZSTD_seqDecompressedSize(seqStore_t const* seqStore, const seqDef* sequences, size_t nbSeq, size_t litSize, int lastSequence) {
408 const seqDef* const sstart = sequences;
409 const seqDef* const send = sequences + nbSeq;
410 const seqDef* sp = sstart;
411 size_t matchLengthSum = 0;
412 size_t litLengthSum __attribute__ ((unused)) = 0;
413 while (send-sp > 0) {
414 ZSTD_sequenceLength const seqLen = ZSTD_getSequenceLength(seqStore, sp);
415 litLengthSum += seqLen.litLength;
416 matchLengthSum += seqLen.matchLength;
417 sp++;
418 }
419 assert(litLengthSum <= litSize);
420 if (!lastSequence) {
421 assert(litLengthSum == litSize);
422 }
423 return matchLengthSum + litSize;
424 }
425
426 /** ZSTD_compressSubBlock_sequences() :
427 * Compresses sequences section for a sub-block.
428 * fseMetadata->llType, fseMetadata->ofType, and fseMetadata->mlType have
429 * symbol compression modes for the super-block.
430 * The first successfully compressed block will have these in its header.
431 * We set entropyWritten=1 when we succeed in compressing the sequences.
432 * The following sub-blocks will always have repeat mode.
433 * @return : compressed size of sequences section of a sub-block
434 * Or 0 if it is unable to compress
435 * Or error code. */
436 static size_t ZSTD_compressSubBlock_sequences(const ZSTD_fseCTables_t* fseTables,
437 const ZSTD_fseCTablesMetadata_t* fseMetadata,
438 const seqDef* sequences, size_t nbSeq,
439 const BYTE* llCode, const BYTE* mlCode, const BYTE* ofCode,
440 const ZSTD_CCtx_params* cctxParams,
441 void* dst, size_t dstCapacity,
442 const int bmi2, int writeEntropy, int* entropyWritten)
443 {
444 const int longOffsets = cctxParams->cParams.windowLog > STREAM_ACCUMULATOR_MIN;
445 BYTE* const ostart = (BYTE*)dst;
446 BYTE* const oend = ostart + dstCapacity;
447 BYTE* op = ostart;
448 BYTE* seqHead;
449
450 DEBUGLOG(5, "ZSTD_compressSubBlock_sequences (nbSeq=%zu, writeEntropy=%d, longOffsets=%d)", nbSeq, writeEntropy, longOffsets);
451
452 *entropyWritten = 0;
453 /* Sequences Header */
454 RETURN_ERROR_IF((oend-op) < 3 /*max nbSeq Size*/ + 1 /*seqHead*/,
455 dstSize_tooSmall, "");
456 if (nbSeq < 0x7F)
457 *op++ = (BYTE)nbSeq;
458 else if (nbSeq < LONGNBSEQ)
459 op[0] = (BYTE)((nbSeq>>8) + 0x80), op[1] = (BYTE)nbSeq, op+=2;
460 else
461 op[0]=0xFF, MEM_writeLE16(op+1, (U16)(nbSeq - LONGNBSEQ)), op+=3;
462 if (nbSeq==0) {
463 return op - ostart;
464 }
465
466 /* seqHead : flags for FSE encoding type */
467 seqHead = op++;
468
469 DEBUGLOG(5, "ZSTD_compressSubBlock_sequences (seqHeadSize=%u)", (unsigned)(op-ostart));
470
471 if (writeEntropy) {
472 const U32 LLtype = fseMetadata->llType;
473 const U32 Offtype = fseMetadata->ofType;
474 const U32 MLtype = fseMetadata->mlType;
475 DEBUGLOG(5, "ZSTD_compressSubBlock_sequences (fseTablesSize=%zu)", fseMetadata->fseTablesSize);
476 *seqHead = (BYTE)((LLtype<<6) + (Offtype<<4) + (MLtype<<2));
477 memcpy(op, fseMetadata->fseTablesBuffer, fseMetadata->fseTablesSize);
478 op += fseMetadata->fseTablesSize;
479 } else {
480 const U32 repeat = set_repeat;
481 *seqHead = (BYTE)((repeat<<6) + (repeat<<4) + (repeat<<2));
482 }
483
484 { size_t const bitstreamSize = ZSTD_encodeSequences(
485 op, oend - op,
486 fseTables->matchlengthCTable, mlCode,
487 fseTables->offcodeCTable, ofCode,
488 fseTables->litlengthCTable, llCode,
489 sequences, nbSeq,
490 longOffsets, bmi2);
491 FORWARD_IF_ERROR(bitstreamSize, "ZSTD_encodeSequences failed");
492 op += bitstreamSize;
493 /* zstd versions <= 1.3.4 mistakenly report corruption when
494 * FSE_readNCount() receives a buffer < 4 bytes.
495 * Fixed by https://github.com/facebook/zstd/pull/1146.
496 * This can happen when the last set_compressed table present is 2
497 * bytes and the bitstream is only one byte.
498 * In this exceedingly rare case, we will simply emit an uncompressed
499 * block, since it isn't worth optimizing.
500 */
501 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
502 if (writeEntropy && fseMetadata->lastCountSize && fseMetadata->lastCountSize + bitstreamSize < 4) {
503 /* NCountSize >= 2 && bitstreamSize > 0 ==> lastCountSize == 3 */
504 assert(fseMetadata->lastCountSize + bitstreamSize == 3);
505 DEBUGLOG(5, "Avoiding bug in zstd decoder in versions <= 1.3.4 by "
506 "emitting an uncompressed block.");
507 return 0;
508 }
509 #endif
510 DEBUGLOG(5, "ZSTD_compressSubBlock_sequences (bitstreamSize=%zu)", bitstreamSize);
511 }
512
513 /* zstd versions <= 1.4.0 mistakenly report error when
514 * sequences section body size is less than 3 bytes.
515 * Fixed by https://github.com/facebook/zstd/pull/1664.
516 * This can happen when the previous sequences section block is compressed
517 * with rle mode and the current block's sequences section is compressed
518 * with repeat mode where sequences section body size can be 1 byte.
519 */
520 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
521 if (op-seqHead < 4) {
522 DEBUGLOG(5, "Avoiding bug in zstd decoder in versions <= 1.4.0 by emitting "
523 "an uncompressed block when sequences are < 4 bytes");
524 return 0;
525 }
526 #endif
527
528 *entropyWritten = 1;
529 return op - ostart;
530 }
531
532 /** ZSTD_compressSubBlock() :
533 * Compresses a single sub-block.
534 * @return : compressed size of the sub-block
535 * Or 0 if it failed to compress. */
536 static size_t ZSTD_compressSubBlock(const ZSTD_entropyCTables_t* entropy,
537 const ZSTD_entropyCTablesMetadata_t* entropyMetadata,
538 const seqDef* sequences, size_t nbSeq,
539 const BYTE* literals, size_t litSize,
540 const BYTE* llCode, const BYTE* mlCode, const BYTE* ofCode,
541 const ZSTD_CCtx_params* cctxParams,
542 void* dst, size_t dstCapacity,
543 const int bmi2,
544 int writeLitEntropy, int writeSeqEntropy,
545 int* litEntropyWritten, int* seqEntropyWritten,
546 U32 lastBlock)
547 {
548 BYTE* const ostart = (BYTE*)dst;
549 BYTE* const oend = ostart + dstCapacity;
550 BYTE* op = ostart + ZSTD_blockHeaderSize;
551 DEBUGLOG(5, "ZSTD_compressSubBlock (litSize=%zu, nbSeq=%zu, writeLitEntropy=%d, writeSeqEntropy=%d, lastBlock=%d)",
552 litSize, nbSeq, writeLitEntropy, writeSeqEntropy, lastBlock);
553 { size_t cLitSize = ZSTD_compressSubBlock_literal((const HUF_CElt*)entropy->huf.CTable,
554 &entropyMetadata->hufMetadata, literals, litSize,
555 op, oend-op, bmi2, writeLitEntropy, litEntropyWritten);
556 FORWARD_IF_ERROR(cLitSize, "ZSTD_compressSubBlock_literal failed");
557 if (cLitSize == 0) return 0;
558 op += cLitSize;
559 }
560 { size_t cSeqSize = ZSTD_compressSubBlock_sequences(&entropy->fse,
561 &entropyMetadata->fseMetadata,
562 sequences, nbSeq,
563 llCode, mlCode, ofCode,
564 cctxParams,
565 op, oend-op,
566 bmi2, writeSeqEntropy, seqEntropyWritten);
567 FORWARD_IF_ERROR(cSeqSize, "ZSTD_compressSubBlock_sequences failed");
568 if (cSeqSize == 0) return 0;
569 op += cSeqSize;
570 }
571 /* Write block header */
572 { size_t cSize = (op-ostart)-ZSTD_blockHeaderSize;
573 U32 const cBlockHeader24 = lastBlock + (((U32)bt_compressed)<<1) + (U32)(cSize << 3);
574 MEM_writeLE24(ostart, cBlockHeader24);
575 }
576 return op-ostart;
577 }
578
579 static size_t ZSTD_estimateSubBlockSize_literal(const BYTE* literals, size_t litSize,
580 const ZSTD_hufCTables_t* huf,
581 const ZSTD_hufCTablesMetadata_t* hufMetadata,
582 void* workspace, size_t wkspSize,
583 int writeEntropy)
584 {
585 unsigned* const countWksp = (unsigned*)workspace;
586 unsigned maxSymbolValue = 255;
587 size_t literalSectionHeaderSize = 3; /* Use hard coded size of 3 bytes */
588
589 if (hufMetadata->hType == set_basic) return litSize;
590 else if (hufMetadata->hType == set_rle) return 1;
591 else if (hufMetadata->hType == set_compressed || hufMetadata->hType == set_repeat) {
592 size_t const largest = HIST_count_wksp (countWksp, &maxSymbolValue, (const BYTE*)literals, litSize, workspace, wkspSize);
593 if (ZSTD_isError(largest)) return litSize;
594 { size_t cLitSizeEstimate = HUF_estimateCompressedSize((const HUF_CElt*)huf->CTable, countWksp, maxSymbolValue);
595 if (writeEntropy) cLitSizeEstimate += hufMetadata->hufDesSize;
596 return cLitSizeEstimate + literalSectionHeaderSize;
597 } }
598 assert(0); /* impossible */
599 return 0;
600 }
601
602 static size_t ZSTD_estimateSubBlockSize_symbolType(symbolEncodingType_e type,
603 const BYTE* codeTable, unsigned maxCode,
604 size_t nbSeq, const FSE_CTable* fseCTable,
605 const U32* additionalBits,
606 short const* defaultNorm, U32 defaultNormLog, U32 defaultMax,
607 void* workspace, size_t wkspSize)
608 {
609 unsigned* const countWksp = (unsigned*)workspace;
610 const BYTE* ctp = codeTable;
611 const BYTE* const ctStart = ctp;
612 const BYTE* const ctEnd = ctStart + nbSeq;
613 size_t cSymbolTypeSizeEstimateInBits = 0;
614 unsigned max = maxCode;
615
616 HIST_countFast_wksp(countWksp, &max, codeTable, nbSeq, workspace, wkspSize); /* can't fail */
617 if (type == set_basic) {
618 /* We selected this encoding type, so it must be valid. */
619 assert(max <= defaultMax);
620 cSymbolTypeSizeEstimateInBits = max <= defaultMax
621 ? ZSTD_crossEntropyCost(defaultNorm, defaultNormLog, countWksp, max)
622 : ERROR(GENERIC);
623 } else if (type == set_rle) {
624 cSymbolTypeSizeEstimateInBits = 0;
625 } else if (type == set_compressed || type == set_repeat) {
626 cSymbolTypeSizeEstimateInBits = ZSTD_fseBitCost(fseCTable, countWksp, max);
627 }
628 if (ZSTD_isError(cSymbolTypeSizeEstimateInBits)) return nbSeq * 10;
629 while (ctp < ctEnd) {
630 if (additionalBits) cSymbolTypeSizeEstimateInBits += additionalBits[*ctp];
631 else cSymbolTypeSizeEstimateInBits += *ctp; /* for offset, offset code is also the number of additional bits */
632 ctp++;
633 }
634 return cSymbolTypeSizeEstimateInBits / 8;
635 }
636
637 static size_t ZSTD_estimateSubBlockSize_sequences(const BYTE* ofCodeTable,
638 const BYTE* llCodeTable,
639 const BYTE* mlCodeTable,
640 size_t nbSeq,
641 const ZSTD_fseCTables_t* fseTables,
642 const ZSTD_fseCTablesMetadata_t* fseMetadata,
643 void* workspace, size_t wkspSize,
644 int writeEntropy)
645 {
646 size_t sequencesSectionHeaderSize = 3; /* Use hard coded size of 3 bytes */
647 size_t cSeqSizeEstimate = 0;
648 cSeqSizeEstimate += ZSTD_estimateSubBlockSize_symbolType(fseMetadata->ofType, ofCodeTable, MaxOff,
649 nbSeq, fseTables->offcodeCTable, NULL,
650 OF_defaultNorm, OF_defaultNormLog, DefaultMaxOff,
651 workspace, wkspSize);
652 cSeqSizeEstimate += ZSTD_estimateSubBlockSize_symbolType(fseMetadata->llType, llCodeTable, MaxLL,
653 nbSeq, fseTables->litlengthCTable, LL_bits,
654 LL_defaultNorm, LL_defaultNormLog, MaxLL,
655 workspace, wkspSize);
656 cSeqSizeEstimate += ZSTD_estimateSubBlockSize_symbolType(fseMetadata->mlType, mlCodeTable, MaxML,
657 nbSeq, fseTables->matchlengthCTable, ML_bits,
658 ML_defaultNorm, ML_defaultNormLog, MaxML,
659 workspace, wkspSize);
660 if (writeEntropy) cSeqSizeEstimate += fseMetadata->fseTablesSize;
661 return cSeqSizeEstimate + sequencesSectionHeaderSize;
662 }
663
664 static size_t ZSTD_estimateSubBlockSize(const BYTE* literals, size_t litSize,
665 const BYTE* ofCodeTable,
666 const BYTE* llCodeTable,
667 const BYTE* mlCodeTable,
668 size_t nbSeq,
669 const ZSTD_entropyCTables_t* entropy,
670 const ZSTD_entropyCTablesMetadata_t* entropyMetadata,
671 void* workspace, size_t wkspSize,
672 int writeLitEntropy, int writeSeqEntropy) {
673 size_t cSizeEstimate = 0;
674 cSizeEstimate += ZSTD_estimateSubBlockSize_literal(literals, litSize,
675 &entropy->huf, &entropyMetadata->hufMetadata,
676 workspace, wkspSize, writeLitEntropy);
677 cSizeEstimate += ZSTD_estimateSubBlockSize_sequences(ofCodeTable, llCodeTable, mlCodeTable,
678 nbSeq, &entropy->fse, &entropyMetadata->fseMetadata,
679 workspace, wkspSize, writeSeqEntropy);
680 return cSizeEstimate + ZSTD_blockHeaderSize;
681 }
682
683 static int ZSTD_needSequenceEntropyTables(ZSTD_fseCTablesMetadata_t const* fseMetadata)
684 {
685 if (fseMetadata->llType == set_compressed || fseMetadata->llType == set_rle)
686 return 1;
687 if (fseMetadata->mlType == set_compressed || fseMetadata->mlType == set_rle)
688 return 1;
689 if (fseMetadata->ofType == set_compressed || fseMetadata->ofType == set_rle)
690 return 1;
691 return 0;
692 }
693
694 /** ZSTD_compressSubBlock_multi() :
695 * Breaks super-block into multiple sub-blocks and compresses them.
696 * Entropy will be written to the first block.
697 * The following blocks will use repeat mode to compress.
698 * All sub-blocks are compressed blocks (no raw or rle blocks).
699 * @return : compressed size of the super block (which is multiple ZSTD blocks)
700 * Or 0 if it failed to compress. */
701 static size_t ZSTD_compressSubBlock_multi(const seqStore_t* seqStorePtr,
702 const ZSTD_compressedBlockState_t* prevCBlock,
703 ZSTD_compressedBlockState_t* nextCBlock,
704 const ZSTD_entropyCTablesMetadata_t* entropyMetadata,
705 const ZSTD_CCtx_params* cctxParams,
706 void* dst, size_t dstCapacity,
707 const void* src, size_t srcSize,
708 const int bmi2, U32 lastBlock,
709 void* workspace, size_t wkspSize)
710 {
711 const seqDef* const sstart = seqStorePtr->sequencesStart;
712 const seqDef* const send = seqStorePtr->sequences;
713 const seqDef* sp = sstart;
714 const BYTE* const lstart = seqStorePtr->litStart;
715 const BYTE* const lend = seqStorePtr->lit;
716 const BYTE* lp = lstart;
717 BYTE const* ip = (BYTE const*)src;
718 BYTE const* const iend = ip + srcSize;
719 BYTE* const ostart = (BYTE*)dst;
720 BYTE* const oend = ostart + dstCapacity;
721 BYTE* op = ostart;
722 const BYTE* llCodePtr = seqStorePtr->llCode;
723 const BYTE* mlCodePtr = seqStorePtr->mlCode;
724 const BYTE* ofCodePtr = seqStorePtr->ofCode;
725 size_t targetCBlockSize = cctxParams->targetCBlockSize;
726 size_t litSize, seqCount;
727 int writeLitEntropy = entropyMetadata->hufMetadata.hType == set_compressed;
728 int writeSeqEntropy = 1;
729 int lastSequence = 0;
730
731 DEBUGLOG(5, "ZSTD_compressSubBlock_multi (litSize=%u, nbSeq=%u)",
732 (unsigned)(lend-lp), (unsigned)(send-sstart));
733
734 litSize = 0;
735 seqCount = 0;
736 do {
737 size_t cBlockSizeEstimate = 0;
738 if (sstart == send) {
739 lastSequence = 1;
740 } else {
741 const seqDef* const sequence = sp + seqCount;
742 lastSequence = sequence == send - 1;
743 litSize += ZSTD_getSequenceLength(seqStorePtr, sequence).litLength;
744 seqCount++;
745 }
746 if (lastSequence) {
747 assert(lp <= lend);
748 assert(litSize <= (size_t)(lend - lp));
749 litSize = (size_t)(lend - lp);
750 }
751 /* I think there is an optimization opportunity here.
752 * Calling ZSTD_estimateSubBlockSize for every sequence can be wasteful
753 * since it recalculates estimate from scratch.
754 * For example, it would recount literal distribution and symbol codes everytime.
755 */
756 cBlockSizeEstimate = ZSTD_estimateSubBlockSize(lp, litSize, ofCodePtr, llCodePtr, mlCodePtr, seqCount,
757 &nextCBlock->entropy, entropyMetadata,
758 workspace, wkspSize, writeLitEntropy, writeSeqEntropy);
759 if (cBlockSizeEstimate > targetCBlockSize || lastSequence) {
760 int litEntropyWritten = 0;
761 int seqEntropyWritten = 0;
762 const size_t decompressedSize = ZSTD_seqDecompressedSize(seqStorePtr, sp, seqCount, litSize, lastSequence);
763 const size_t cSize = ZSTD_compressSubBlock(&nextCBlock->entropy, entropyMetadata,
764 sp, seqCount,
765 lp, litSize,
766 llCodePtr, mlCodePtr, ofCodePtr,
767 cctxParams,
768 op, oend-op,
769 bmi2, writeLitEntropy, writeSeqEntropy,
770 &litEntropyWritten, &seqEntropyWritten,
771 lastBlock && lastSequence);
772 FORWARD_IF_ERROR(cSize, "ZSTD_compressSubBlock failed");
773 if (cSize > 0 && cSize < decompressedSize) {
774 DEBUGLOG(5, "Committed the sub-block");
775 assert(ip + decompressedSize <= iend);
776 ip += decompressedSize;
777 sp += seqCount;
778 lp += litSize;
779 op += cSize;
780 llCodePtr += seqCount;
781 mlCodePtr += seqCount;
782 ofCodePtr += seqCount;
783 litSize = 0;
784 seqCount = 0;
785 /* Entropy only needs to be written once */
786 if (litEntropyWritten) {
787 writeLitEntropy = 0;
788 }
789 if (seqEntropyWritten) {
790 writeSeqEntropy = 0;
791 }
792 }
793 }
794 } while (!lastSequence);
795 if (writeLitEntropy) {
796 DEBUGLOG(5, "ZSTD_compressSubBlock_multi has literal entropy tables unwritten");
797 memcpy(&nextCBlock->entropy.huf, &prevCBlock->entropy.huf, sizeof(prevCBlock->entropy.huf));
798 }
799 if (writeSeqEntropy && ZSTD_needSequenceEntropyTables(&entropyMetadata->fseMetadata)) {
800 /* If we haven't written our entropy tables, then we've violated our contract and
801 * must emit an uncompressed block.
802 */
803 DEBUGLOG(5, "ZSTD_compressSubBlock_multi has sequence entropy tables unwritten");
804 return 0;
805 }
806 if (ip < iend) {
807 size_t const cSize = ZSTD_noCompressBlock(op, oend - op, ip, iend - ip, lastBlock);
808 DEBUGLOG(5, "ZSTD_compressSubBlock_multi last sub-block uncompressed, %zu bytes", (size_t)(iend - ip));
809 FORWARD_IF_ERROR(cSize, "ZSTD_noCompressBlock failed");
810 assert(cSize != 0);
811 op += cSize;
812 /* We have to regenerate the repcodes because we've skipped some sequences */
813 if (sp < send) {
814 seqDef const* seq;
815 repcodes_t rep;
816 memcpy(&rep, prevCBlock->rep, sizeof(rep));
817 for (seq = sstart; seq < sp; ++seq) {
818 rep = ZSTD_updateRep(rep.rep, seq->offset - 1, ZSTD_getSequenceLength(seqStorePtr, seq).litLength == 0);
819 }
820 memcpy(nextCBlock->rep, &rep, sizeof(rep));
821 }
822 }
823 DEBUGLOG(5, "ZSTD_compressSubBlock_multi compressed");
824 return op-ostart;
825 }
826
827 size_t ZSTD_compressSuperBlock(ZSTD_CCtx* zc,
828 void* dst, size_t dstCapacity,
829 void const* src, size_t srcSize,
830 unsigned lastBlock) {
831 ZSTD_entropyCTablesMetadata_t entropyMetadata;
832
833 FORWARD_IF_ERROR(ZSTD_buildSuperBlockEntropy(&zc->seqStore,
834 &zc->blockState.prevCBlock->entropy,
835 &zc->blockState.nextCBlock->entropy,
836 &zc->appliedParams,
837 &entropyMetadata,
838 zc->entropyWorkspace, HUF_WORKSPACE_SIZE /* statically allocated in resetCCtx */), "");
839
840 return ZSTD_compressSubBlock_multi(&zc->seqStore,
841 zc->blockState.prevCBlock,
842 zc->blockState.nextCBlock,
843 &entropyMetadata,
844 &zc->appliedParams,
845 dst, dstCapacity,
846 src, srcSize,
847 zc->bmi2, lastBlock,
848 zc->entropyWorkspace, HUF_WORKSPACE_SIZE /* statically allocated in resetCCtx */);
849 }
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