1 /*
2  * Copyright (c) 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"   /* ZSTD_[huf|fse|entropy]CTablesMetadata_t */
19 #include "zstd_compress_sequences.h"
20 #include "zstd_compress_literals.h"
21 
22 /* ZSTD_compressSubBlock_literal() :
23  *  Compresses literals section for a sub-block.
24  *  When we have to write the Huffman table we will sometimes choose a header
25  *  size larger than necessary. This is because we have to pick the header size
26  *  before we know the table size + compressed size, so we have a bound on the
27  *  table size. If we guessed incorrectly, we fall back to uncompressed literals.
28  *
29  *  We write the header when writeEntropy=1 and set entropyWritten=1 when we succeeded
30  *  in writing the header, otherwise it is set to 0.
31  *
32  *  hufMetadata->hType has literals block type info.
33  *      If it is set_basic, all sub-blocks literals section will be Raw_Literals_Block.
34  *      If it is set_rle, all sub-blocks literals section will be RLE_Literals_Block.
35  *      If it is set_compressed, first sub-block's literals section will be Compressed_Literals_Block
36  *      If it is set_compressed, first sub-block's literals section will be Treeless_Literals_Block
37  *      and the following sub-blocks' literals sections will be Treeless_Literals_Block.
38  *  @return : compressed size of literals section of a sub-block
39  *            Or 0 if it unable to compress.
40  *            Or error code */
ZSTD_compressSubBlock_literal(const HUF_CElt * hufTable,const ZSTD_hufCTablesMetadata_t * hufMetadata,const BYTE * literals,size_t litSize,void * dst,size_t dstSize,const int bmi2,int writeEntropy,int * entropyWritten)41 static size_t ZSTD_compressSubBlock_literal(const HUF_CElt* hufTable,
42                                     const ZSTD_hufCTablesMetadata_t* hufMetadata,
43                                     const BYTE* literals, size_t litSize,
44                                     void* dst, size_t dstSize,
45                                     const int bmi2, int writeEntropy, int* entropyWritten)
46 {
47     size_t const header = writeEntropy ? 200 : 0;
48     size_t const lhSize = 3 + (litSize >= (1 KB - header)) + (litSize >= (16 KB - header));
49     BYTE* const ostart = (BYTE*)dst;
50     BYTE* const oend = ostart + dstSize;
51     BYTE* op = ostart + lhSize;
52     U32 const singleStream = lhSize == 3;
53     symbolEncodingType_e hType = writeEntropy ? hufMetadata->hType : set_repeat;
54     size_t cLitSize = 0;
55 
56     (void)bmi2; /* TODO bmi2... */
57 
58     DEBUGLOG(5, "ZSTD_compressSubBlock_literal (litSize=%zu, lhSize=%zu, writeEntropy=%d)", litSize, lhSize, writeEntropy);
59 
60     *entropyWritten = 0;
61     if (litSize == 0 || hufMetadata->hType == set_basic) {
62       DEBUGLOG(5, "ZSTD_compressSubBlock_literal using raw literal");
63       return ZSTD_noCompressLiterals(dst, dstSize, literals, litSize);
64     } else if (hufMetadata->hType == set_rle) {
65       DEBUGLOG(5, "ZSTD_compressSubBlock_literal using rle literal");
66       return ZSTD_compressRleLiteralsBlock(dst, dstSize, literals, litSize);
67     }
68 
69     assert(litSize > 0);
70     assert(hufMetadata->hType == set_compressed || hufMetadata->hType == set_repeat);
71 
72     if (writeEntropy && hufMetadata->hType == set_compressed) {
73         ZSTD_memcpy(op, hufMetadata->hufDesBuffer, hufMetadata->hufDesSize);
74         op += hufMetadata->hufDesSize;
75         cLitSize += hufMetadata->hufDesSize;
76         DEBUGLOG(5, "ZSTD_compressSubBlock_literal (hSize=%zu)", hufMetadata->hufDesSize);
77     }
78 
79     /* TODO bmi2 */
80     {   const size_t cSize = singleStream ? HUF_compress1X_usingCTable(op, oend-op, literals, litSize, hufTable)
81                                           : HUF_compress4X_usingCTable(op, oend-op, literals, litSize, hufTable);
82         op += cSize;
83         cLitSize += cSize;
84         if (cSize == 0 || ERR_isError(cSize)) {
85             DEBUGLOG(5, "Failed to write entropy tables %s", ZSTD_getErrorName(cSize));
86             return 0;
87         }
88         /* If we expand and we aren't writing a header then emit uncompressed */
89         if (!writeEntropy && cLitSize >= litSize) {
90             DEBUGLOG(5, "ZSTD_compressSubBlock_literal using raw literal because uncompressible");
91             return ZSTD_noCompressLiterals(dst, dstSize, literals, litSize);
92         }
93         /* If we are writing headers then allow expansion that doesn't change our header size. */
94         if (lhSize < (size_t)(3 + (cLitSize >= 1 KB) + (cLitSize >= 16 KB))) {
95             assert(cLitSize > litSize);
96             DEBUGLOG(5, "Literals expanded beyond allowed header size");
97             return ZSTD_noCompressLiterals(dst, dstSize, literals, litSize);
98         }
99         DEBUGLOG(5, "ZSTD_compressSubBlock_literal (cSize=%zu)", cSize);
100     }
101 
102     /* Build header */
103     switch(lhSize)
104     {
105     case 3: /* 2 - 2 - 10 - 10 */
106         {   U32 const lhc = hType + ((!singleStream) << 2) + ((U32)litSize<<4) + ((U32)cLitSize<<14);
107             MEM_writeLE24(ostart, lhc);
108             break;
109         }
110     case 4: /* 2 - 2 - 14 - 14 */
111         {   U32 const lhc = hType + (2 << 2) + ((U32)litSize<<4) + ((U32)cLitSize<<18);
112             MEM_writeLE32(ostart, lhc);
113             break;
114         }
115     case 5: /* 2 - 2 - 18 - 18 */
116         {   U32 const lhc = hType + (3 << 2) + ((U32)litSize<<4) + ((U32)cLitSize<<22);
117             MEM_writeLE32(ostart, lhc);
118             ostart[4] = (BYTE)(cLitSize >> 10);
119             break;
120         }
121     default:  /* not possible : lhSize is {3,4,5} */
122         assert(0);
123     }
124     *entropyWritten = 1;
125     DEBUGLOG(5, "Compressed literals: %u -> %u", (U32)litSize, (U32)(op-ostart));
126     return op-ostart;
127 }
128 
ZSTD_seqDecompressedSize(seqStore_t const * seqStore,const seqDef * sequences,size_t nbSeq,size_t litSize,int lastSequence)129 static size_t ZSTD_seqDecompressedSize(seqStore_t const* seqStore, const seqDef* sequences, size_t nbSeq, size_t litSize, int lastSequence) {
130     const seqDef* const sstart = sequences;
131     const seqDef* const send = sequences + nbSeq;
132     const seqDef* sp = sstart;
133     size_t matchLengthSum = 0;
134     size_t litLengthSum = 0;
135     (void)(litLengthSum); /* suppress unused variable warning on some environments */
136     while (send-sp > 0) {
137         ZSTD_sequenceLength const seqLen = ZSTD_getSequenceLength(seqStore, sp);
138         litLengthSum += seqLen.litLength;
139         matchLengthSum += seqLen.matchLength;
140         sp++;
141     }
142     assert(litLengthSum <= litSize);
143     if (!lastSequence) {
144         assert(litLengthSum == litSize);
145     }
146     return matchLengthSum + litSize;
147 }
148 
149 /* ZSTD_compressSubBlock_sequences() :
150  *  Compresses sequences section for a sub-block.
151  *  fseMetadata->llType, fseMetadata->ofType, and fseMetadata->mlType have
152  *  symbol compression modes for the super-block.
153  *  The first successfully compressed block will have these in its header.
154  *  We set entropyWritten=1 when we succeed in compressing the sequences.
155  *  The following sub-blocks will always have repeat mode.
156  *  @return : compressed size of sequences section of a sub-block
157  *            Or 0 if it is unable to compress
158  *            Or error code. */
ZSTD_compressSubBlock_sequences(const ZSTD_fseCTables_t * fseTables,const ZSTD_fseCTablesMetadata_t * fseMetadata,const seqDef * sequences,size_t nbSeq,const BYTE * llCode,const BYTE * mlCode,const BYTE * ofCode,const ZSTD_CCtx_params * cctxParams,void * dst,size_t dstCapacity,const int bmi2,int writeEntropy,int * entropyWritten)159 static size_t ZSTD_compressSubBlock_sequences(const ZSTD_fseCTables_t* fseTables,
160                                               const ZSTD_fseCTablesMetadata_t* fseMetadata,
161                                               const seqDef* sequences, size_t nbSeq,
162                                               const BYTE* llCode, const BYTE* mlCode, const BYTE* ofCode,
163                                               const ZSTD_CCtx_params* cctxParams,
164                                               void* dst, size_t dstCapacity,
165                                               const int bmi2, int writeEntropy, int* entropyWritten)
166 {
167     const int longOffsets = cctxParams->cParams.windowLog > STREAM_ACCUMULATOR_MIN;
168     BYTE* const ostart = (BYTE*)dst;
169     BYTE* const oend = ostart + dstCapacity;
170     BYTE* op = ostart;
171     BYTE* seqHead;
172 
173     DEBUGLOG(5, "ZSTD_compressSubBlock_sequences (nbSeq=%zu, writeEntropy=%d, longOffsets=%d)", nbSeq, writeEntropy, longOffsets);
174 
175     *entropyWritten = 0;
176     /* Sequences Header */
177     RETURN_ERROR_IF((oend-op) < 3 /*max nbSeq Size*/ + 1 /*seqHead*/,
178                     dstSize_tooSmall, "");
179     if (nbSeq < 0x7F)
180         *op++ = (BYTE)nbSeq;
181     else if (nbSeq < LONGNBSEQ)
182         op[0] = (BYTE)((nbSeq>>8) + 0x80), op[1] = (BYTE)nbSeq, op+=2;
183     else
184         op[0]=0xFF, MEM_writeLE16(op+1, (U16)(nbSeq - LONGNBSEQ)), op+=3;
185     if (nbSeq==0) {
186         return op - ostart;
187     }
188 
189     /* seqHead : flags for FSE encoding type */
190     seqHead = op++;
191 
192     DEBUGLOG(5, "ZSTD_compressSubBlock_sequences (seqHeadSize=%u)", (unsigned)(op-ostart));
193 
194     if (writeEntropy) {
195         const U32 LLtype = fseMetadata->llType;
196         const U32 Offtype = fseMetadata->ofType;
197         const U32 MLtype = fseMetadata->mlType;
198         DEBUGLOG(5, "ZSTD_compressSubBlock_sequences (fseTablesSize=%zu)", fseMetadata->fseTablesSize);
199         *seqHead = (BYTE)((LLtype<<6) + (Offtype<<4) + (MLtype<<2));
200         ZSTD_memcpy(op, fseMetadata->fseTablesBuffer, fseMetadata->fseTablesSize);
201         op += fseMetadata->fseTablesSize;
202     } else {
203         const U32 repeat = set_repeat;
204         *seqHead = (BYTE)((repeat<<6) + (repeat<<4) + (repeat<<2));
205     }
206 
207     {   size_t const bitstreamSize = ZSTD_encodeSequences(
208                                         op, oend - op,
209                                         fseTables->matchlengthCTable, mlCode,
210                                         fseTables->offcodeCTable, ofCode,
211                                         fseTables->litlengthCTable, llCode,
212                                         sequences, nbSeq,
213                                         longOffsets, bmi2);
214         FORWARD_IF_ERROR(bitstreamSize, "ZSTD_encodeSequences failed");
215         op += bitstreamSize;
216         /* zstd versions <= 1.3.4 mistakenly report corruption when
217          * FSE_readNCount() receives a buffer < 4 bytes.
218          * Fixed by https://github.com/facebook/zstd/pull/1146.
219          * This can happen when the last set_compressed table present is 2
220          * bytes and the bitstream is only one byte.
221          * In this exceedingly rare case, we will simply emit an uncompressed
222          * block, since it isn't worth optimizing.
223          */
224 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
225         if (writeEntropy && fseMetadata->lastCountSize && fseMetadata->lastCountSize + bitstreamSize < 4) {
226             /* NCountSize >= 2 && bitstreamSize > 0 ==> lastCountSize == 3 */
227             assert(fseMetadata->lastCountSize + bitstreamSize == 3);
228             DEBUGLOG(5, "Avoiding bug in zstd decoder in versions <= 1.3.4 by "
229                         "emitting an uncompressed block.");
230             return 0;
231         }
232 #endif
233         DEBUGLOG(5, "ZSTD_compressSubBlock_sequences (bitstreamSize=%zu)", bitstreamSize);
234     }
235 
236     /* zstd versions <= 1.4.0 mistakenly report error when
237      * sequences section body size is less than 3 bytes.
238      * Fixed by https://github.com/facebook/zstd/pull/1664.
239      * This can happen when the previous sequences section block is compressed
240      * with rle mode and the current block's sequences section is compressed
241      * with repeat mode where sequences section body size can be 1 byte.
242      */
243 #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
244     if (op-seqHead < 4) {
245         DEBUGLOG(5, "Avoiding bug in zstd decoder in versions <= 1.4.0 by emitting "
246                     "an uncompressed block when sequences are < 4 bytes");
247         return 0;
248     }
249 #endif
250 
251     *entropyWritten = 1;
252     return op - ostart;
253 }
254 
255 /* ZSTD_compressSubBlock() :
256  *  Compresses a single sub-block.
257  *  @return : compressed size of the sub-block
258  *            Or 0 if it failed to compress. */
ZSTD_compressSubBlock(const ZSTD_entropyCTables_t * entropy,const ZSTD_entropyCTablesMetadata_t * entropyMetadata,const seqDef * sequences,size_t nbSeq,const BYTE * literals,size_t litSize,const BYTE * llCode,const BYTE * mlCode,const BYTE * ofCode,const ZSTD_CCtx_params * cctxParams,void * dst,size_t dstCapacity,const int bmi2,int writeLitEntropy,int writeSeqEntropy,int * litEntropyWritten,int * seqEntropyWritten,U32 lastBlock)259 static size_t ZSTD_compressSubBlock(const ZSTD_entropyCTables_t* entropy,
260                                     const ZSTD_entropyCTablesMetadata_t* entropyMetadata,
261                                     const seqDef* sequences, size_t nbSeq,
262                                     const BYTE* literals, size_t litSize,
263                                     const BYTE* llCode, const BYTE* mlCode, const BYTE* ofCode,
264                                     const ZSTD_CCtx_params* cctxParams,
265                                     void* dst, size_t dstCapacity,
266                                     const int bmi2,
267                                     int writeLitEntropy, int writeSeqEntropy,
268                                     int* litEntropyWritten, int* seqEntropyWritten,
269                                     U32 lastBlock)
270 {
271     BYTE* const ostart = (BYTE*)dst;
272     BYTE* const oend = ostart + dstCapacity;
273     BYTE* op = ostart + ZSTD_blockHeaderSize;
274     DEBUGLOG(5, "ZSTD_compressSubBlock (litSize=%zu, nbSeq=%zu, writeLitEntropy=%d, writeSeqEntropy=%d, lastBlock=%d)",
275                 litSize, nbSeq, writeLitEntropy, writeSeqEntropy, lastBlock);
276     {   size_t cLitSize = ZSTD_compressSubBlock_literal((const HUF_CElt*)entropy->huf.CTable,
277                                                         &entropyMetadata->hufMetadata, literals, litSize,
278                                                         op, oend-op, bmi2, writeLitEntropy, litEntropyWritten);
279         FORWARD_IF_ERROR(cLitSize, "ZSTD_compressSubBlock_literal failed");
280         if (cLitSize == 0) return 0;
281         op += cLitSize;
282     }
283     {   size_t cSeqSize = ZSTD_compressSubBlock_sequences(&entropy->fse,
284                                                   &entropyMetadata->fseMetadata,
285                                                   sequences, nbSeq,
286                                                   llCode, mlCode, ofCode,
287                                                   cctxParams,
288                                                   op, oend-op,
289                                                   bmi2, writeSeqEntropy, seqEntropyWritten);
290         FORWARD_IF_ERROR(cSeqSize, "ZSTD_compressSubBlock_sequences failed");
291         if (cSeqSize == 0) return 0;
292         op += cSeqSize;
293     }
294     /* Write block header */
295     {   size_t cSize = (op-ostart)-ZSTD_blockHeaderSize;
296         U32 const cBlockHeader24 = lastBlock + (((U32)bt_compressed)<<1) + (U32)(cSize << 3);
297         MEM_writeLE24(ostart, cBlockHeader24);
298     }
299     return op-ostart;
300 }
301 
ZSTD_estimateSubBlockSize_literal(const BYTE * literals,size_t litSize,const ZSTD_hufCTables_t * huf,const ZSTD_hufCTablesMetadata_t * hufMetadata,void * workspace,size_t wkspSize,int writeEntropy)302 static size_t ZSTD_estimateSubBlockSize_literal(const BYTE* literals, size_t litSize,
303                                                 const ZSTD_hufCTables_t* huf,
304                                                 const ZSTD_hufCTablesMetadata_t* hufMetadata,
305                                                 void* workspace, size_t wkspSize,
306                                                 int writeEntropy)
307 {
308     unsigned* const countWksp = (unsigned*)workspace;
309     unsigned maxSymbolValue = 255;
310     size_t literalSectionHeaderSize = 3; /* Use hard coded size of 3 bytes */
311 
312     if (hufMetadata->hType == set_basic) return litSize;
313     else if (hufMetadata->hType == set_rle) return 1;
314     else if (hufMetadata->hType == set_compressed || hufMetadata->hType == set_repeat) {
315         size_t const largest = HIST_count_wksp (countWksp, &maxSymbolValue, (const BYTE*)literals, litSize, workspace, wkspSize);
316         if (ZSTD_isError(largest)) return litSize;
317         {   size_t cLitSizeEstimate = HUF_estimateCompressedSize((const HUF_CElt*)huf->CTable, countWksp, maxSymbolValue);
318             if (writeEntropy) cLitSizeEstimate += hufMetadata->hufDesSize;
319             return cLitSizeEstimate + literalSectionHeaderSize;
320     }   }
321     assert(0); /* impossible */
322     return 0;
323 }
324 
ZSTD_estimateSubBlockSize_symbolType(symbolEncodingType_e type,const BYTE * codeTable,unsigned maxCode,size_t nbSeq,const FSE_CTable * fseCTable,const U8 * additionalBits,short const * defaultNorm,U32 defaultNormLog,U32 defaultMax,void * workspace,size_t wkspSize)325 static size_t ZSTD_estimateSubBlockSize_symbolType(symbolEncodingType_e type,
326                         const BYTE* codeTable, unsigned maxCode,
327                         size_t nbSeq, const FSE_CTable* fseCTable,
328                         const U8* additionalBits,
329                         short const* defaultNorm, U32 defaultNormLog, U32 defaultMax,
330                         void* workspace, size_t wkspSize)
331 {
332     unsigned* const countWksp = (unsigned*)workspace;
333     const BYTE* ctp = codeTable;
334     const BYTE* const ctStart = ctp;
335     const BYTE* const ctEnd = ctStart + nbSeq;
336     size_t cSymbolTypeSizeEstimateInBits = 0;
337     unsigned max = maxCode;
338 
339     HIST_countFast_wksp(countWksp, &max, codeTable, nbSeq, workspace, wkspSize);  /* can't fail */
340     if (type == set_basic) {
341         /* We selected this encoding type, so it must be valid. */
342         assert(max <= defaultMax);
343         cSymbolTypeSizeEstimateInBits = max <= defaultMax
344                 ? ZSTD_crossEntropyCost(defaultNorm, defaultNormLog, countWksp, max)
345                 : ERROR(GENERIC);
346     } else if (type == set_rle) {
347         cSymbolTypeSizeEstimateInBits = 0;
348     } else if (type == set_compressed || type == set_repeat) {
349         cSymbolTypeSizeEstimateInBits = ZSTD_fseBitCost(fseCTable, countWksp, max);
350     }
351     if (ZSTD_isError(cSymbolTypeSizeEstimateInBits)) return nbSeq * 10;
352     while (ctp < ctEnd) {
353         if (additionalBits) cSymbolTypeSizeEstimateInBits += additionalBits[*ctp];
354         else cSymbolTypeSizeEstimateInBits += *ctp; /* for offset, offset code is also the number of additional bits */
355         ctp++;
356     }
357     return cSymbolTypeSizeEstimateInBits / 8;
358 }
359 
ZSTD_estimateSubBlockSize_sequences(const BYTE * ofCodeTable,const BYTE * llCodeTable,const BYTE * mlCodeTable,size_t nbSeq,const ZSTD_fseCTables_t * fseTables,const ZSTD_fseCTablesMetadata_t * fseMetadata,void * workspace,size_t wkspSize,int writeEntropy)360 static size_t ZSTD_estimateSubBlockSize_sequences(const BYTE* ofCodeTable,
361                                                   const BYTE* llCodeTable,
362                                                   const BYTE* mlCodeTable,
363                                                   size_t nbSeq,
364                                                   const ZSTD_fseCTables_t* fseTables,
365                                                   const ZSTD_fseCTablesMetadata_t* fseMetadata,
366                                                   void* workspace, size_t wkspSize,
367                                                   int writeEntropy)
368 {
369     size_t const sequencesSectionHeaderSize = 3; /* Use hard coded size of 3 bytes */
370     size_t cSeqSizeEstimate = 0;
371     if (nbSeq == 0) return sequencesSectionHeaderSize;
372     cSeqSizeEstimate += ZSTD_estimateSubBlockSize_symbolType(fseMetadata->ofType, ofCodeTable, MaxOff,
373                                          nbSeq, fseTables->offcodeCTable, NULL,
374                                          OF_defaultNorm, OF_defaultNormLog, DefaultMaxOff,
375                                          workspace, wkspSize);
376     cSeqSizeEstimate += ZSTD_estimateSubBlockSize_symbolType(fseMetadata->llType, llCodeTable, MaxLL,
377                                          nbSeq, fseTables->litlengthCTable, LL_bits,
378                                          LL_defaultNorm, LL_defaultNormLog, MaxLL,
379                                          workspace, wkspSize);
380     cSeqSizeEstimate += ZSTD_estimateSubBlockSize_symbolType(fseMetadata->mlType, mlCodeTable, MaxML,
381                                          nbSeq, fseTables->matchlengthCTable, ML_bits,
382                                          ML_defaultNorm, ML_defaultNormLog, MaxML,
383                                          workspace, wkspSize);
384     if (writeEntropy) cSeqSizeEstimate += fseMetadata->fseTablesSize;
385     return cSeqSizeEstimate + sequencesSectionHeaderSize;
386 }
387 
ZSTD_estimateSubBlockSize(const BYTE * literals,size_t litSize,const BYTE * ofCodeTable,const BYTE * llCodeTable,const BYTE * mlCodeTable,size_t nbSeq,const ZSTD_entropyCTables_t * entropy,const ZSTD_entropyCTablesMetadata_t * entropyMetadata,void * workspace,size_t wkspSize,int writeLitEntropy,int writeSeqEntropy)388 static size_t ZSTD_estimateSubBlockSize(const BYTE* literals, size_t litSize,
389                                         const BYTE* ofCodeTable,
390                                         const BYTE* llCodeTable,
391                                         const BYTE* mlCodeTable,
392                                         size_t nbSeq,
393                                         const ZSTD_entropyCTables_t* entropy,
394                                         const ZSTD_entropyCTablesMetadata_t* entropyMetadata,
395                                         void* workspace, size_t wkspSize,
396                                         int writeLitEntropy, int writeSeqEntropy) {
397     size_t cSizeEstimate = 0;
398     cSizeEstimate += ZSTD_estimateSubBlockSize_literal(literals, litSize,
399                                                          &entropy->huf, &entropyMetadata->hufMetadata,
400                                                          workspace, wkspSize, writeLitEntropy);
401     cSizeEstimate += ZSTD_estimateSubBlockSize_sequences(ofCodeTable, llCodeTable, mlCodeTable,
402                                                          nbSeq, &entropy->fse, &entropyMetadata->fseMetadata,
403                                                          workspace, wkspSize, writeSeqEntropy);
404     return cSizeEstimate + ZSTD_blockHeaderSize;
405 }
406 
ZSTD_needSequenceEntropyTables(ZSTD_fseCTablesMetadata_t const * fseMetadata)407 static int ZSTD_needSequenceEntropyTables(ZSTD_fseCTablesMetadata_t const* fseMetadata)
408 {
409     if (fseMetadata->llType == set_compressed || fseMetadata->llType == set_rle)
410         return 1;
411     if (fseMetadata->mlType == set_compressed || fseMetadata->mlType == set_rle)
412         return 1;
413     if (fseMetadata->ofType == set_compressed || fseMetadata->ofType == set_rle)
414         return 1;
415     return 0;
416 }
417 
418 /* ZSTD_compressSubBlock_multi() :
419  *  Breaks super-block into multiple sub-blocks and compresses them.
420  *  Entropy will be written to the first block.
421  *  The following blocks will use repeat mode to compress.
422  *  All sub-blocks are compressed blocks (no raw or rle blocks).
423  *  @return : compressed size of the super block (which is multiple ZSTD blocks)
424  *            Or 0 if it failed to compress. */
ZSTD_compressSubBlock_multi(const seqStore_t * seqStorePtr,const ZSTD_compressedBlockState_t * prevCBlock,ZSTD_compressedBlockState_t * nextCBlock,const ZSTD_entropyCTablesMetadata_t * entropyMetadata,const ZSTD_CCtx_params * cctxParams,void * dst,size_t dstCapacity,const void * src,size_t srcSize,const int bmi2,U32 lastBlock,void * workspace,size_t wkspSize)425 static size_t ZSTD_compressSubBlock_multi(const seqStore_t* seqStorePtr,
426                             const ZSTD_compressedBlockState_t* prevCBlock,
427                             ZSTD_compressedBlockState_t* nextCBlock,
428                             const ZSTD_entropyCTablesMetadata_t* entropyMetadata,
429                             const ZSTD_CCtx_params* cctxParams,
430                                   void* dst, size_t dstCapacity,
431                             const void* src, size_t srcSize,
432                             const int bmi2, U32 lastBlock,
433                             void* workspace, size_t wkspSize)
434 {
435     const seqDef* const sstart = seqStorePtr->sequencesStart;
436     const seqDef* const send = seqStorePtr->sequences;
437     const seqDef* sp = sstart;
438     const BYTE* const lstart = seqStorePtr->litStart;
439     const BYTE* const lend = seqStorePtr->lit;
440     const BYTE* lp = lstart;
441     BYTE const* ip = (BYTE const*)src;
442     BYTE const* const iend = ip + srcSize;
443     BYTE* const ostart = (BYTE*)dst;
444     BYTE* const oend = ostart + dstCapacity;
445     BYTE* op = ostart;
446     const BYTE* llCodePtr = seqStorePtr->llCode;
447     const BYTE* mlCodePtr = seqStorePtr->mlCode;
448     const BYTE* ofCodePtr = seqStorePtr->ofCode;
449     size_t targetCBlockSize = cctxParams->targetCBlockSize;
450     size_t litSize, seqCount;
451     int writeLitEntropy = entropyMetadata->hufMetadata.hType == set_compressed;
452     int writeSeqEntropy = 1;
453     int lastSequence = 0;
454 
455     DEBUGLOG(5, "ZSTD_compressSubBlock_multi (litSize=%u, nbSeq=%u)",
456                 (unsigned)(lend-lp), (unsigned)(send-sstart));
457 
458     litSize = 0;
459     seqCount = 0;
460     do {
461         size_t cBlockSizeEstimate = 0;
462         if (sstart == send) {
463             lastSequence = 1;
464         } else {
465             const seqDef* const sequence = sp + seqCount;
466             lastSequence = sequence == send - 1;
467             litSize += ZSTD_getSequenceLength(seqStorePtr, sequence).litLength;
468             seqCount++;
469         }
470         if (lastSequence) {
471             assert(lp <= lend);
472             assert(litSize <= (size_t)(lend - lp));
473             litSize = (size_t)(lend - lp);
474         }
475         /* I think there is an optimization opportunity here.
476          * Calling ZSTD_estimateSubBlockSize for every sequence can be wasteful
477          * since it recalculates estimate from scratch.
478          * For example, it would recount literal distribution and symbol codes every time.
479          */
480         cBlockSizeEstimate = ZSTD_estimateSubBlockSize(lp, litSize, ofCodePtr, llCodePtr, mlCodePtr, seqCount,
481                                                        &nextCBlock->entropy, entropyMetadata,
482                                                        workspace, wkspSize, writeLitEntropy, writeSeqEntropy);
483         if (cBlockSizeEstimate > targetCBlockSize || lastSequence) {
484             int litEntropyWritten = 0;
485             int seqEntropyWritten = 0;
486             const size_t decompressedSize = ZSTD_seqDecompressedSize(seqStorePtr, sp, seqCount, litSize, lastSequence);
487             const size_t cSize = ZSTD_compressSubBlock(&nextCBlock->entropy, entropyMetadata,
488                                                        sp, seqCount,
489                                                        lp, litSize,
490                                                        llCodePtr, mlCodePtr, ofCodePtr,
491                                                        cctxParams,
492                                                        op, oend-op,
493                                                        bmi2, writeLitEntropy, writeSeqEntropy,
494                                                        &litEntropyWritten, &seqEntropyWritten,
495                                                        lastBlock && lastSequence);
496             FORWARD_IF_ERROR(cSize, "ZSTD_compressSubBlock failed");
497             if (cSize > 0 && cSize < decompressedSize) {
498                 DEBUGLOG(5, "Committed the sub-block");
499                 assert(ip + decompressedSize <= iend);
500                 ip += decompressedSize;
501                 sp += seqCount;
502                 lp += litSize;
503                 op += cSize;
504                 llCodePtr += seqCount;
505                 mlCodePtr += seqCount;
506                 ofCodePtr += seqCount;
507                 litSize = 0;
508                 seqCount = 0;
509                 /* Entropy only needs to be written once */
510                 if (litEntropyWritten) {
511                     writeLitEntropy = 0;
512                 }
513                 if (seqEntropyWritten) {
514                     writeSeqEntropy = 0;
515                 }
516             }
517         }
518     } while (!lastSequence);
519     if (writeLitEntropy) {
520         DEBUGLOG(5, "ZSTD_compressSubBlock_multi has literal entropy tables unwritten");
521         ZSTD_memcpy(&nextCBlock->entropy.huf, &prevCBlock->entropy.huf, sizeof(prevCBlock->entropy.huf));
522     }
523     if (writeSeqEntropy && ZSTD_needSequenceEntropyTables(&entropyMetadata->fseMetadata)) {
524         /* If we haven't written our entropy tables, then we've violated our contract and
525          * must emit an uncompressed block.
526          */
527         DEBUGLOG(5, "ZSTD_compressSubBlock_multi has sequence entropy tables unwritten");
528         return 0;
529     }
530     if (ip < iend) {
531         size_t const cSize = ZSTD_noCompressBlock(op, oend - op, ip, iend - ip, lastBlock);
532         DEBUGLOG(5, "ZSTD_compressSubBlock_multi last sub-block uncompressed, %zu bytes", (size_t)(iend - ip));
533         FORWARD_IF_ERROR(cSize, "ZSTD_noCompressBlock failed");
534         assert(cSize != 0);
535         op += cSize;
536         /* We have to regenerate the repcodes because we've skipped some sequences */
537         if (sp < send) {
538             seqDef const* seq;
539             repcodes_t rep;
540             ZSTD_memcpy(&rep, prevCBlock->rep, sizeof(rep));
541             for (seq = sstart; seq < sp; ++seq) {
542                 ZSTD_updateRep(rep.rep, seq->offBase - 1, ZSTD_getSequenceLength(seqStorePtr, seq).litLength == 0);
543             }
544             ZSTD_memcpy(nextCBlock->rep, &rep, sizeof(rep));
545         }
546     }
547     DEBUGLOG(5, "ZSTD_compressSubBlock_multi compressed");
548     return op-ostart;
549 }
550 
ZSTD_compressSuperBlock(ZSTD_CCtx * zc,void * dst,size_t dstCapacity,void const * src,size_t srcSize,unsigned lastBlock)551 size_t ZSTD_compressSuperBlock(ZSTD_CCtx* zc,
552                                void* dst, size_t dstCapacity,
553                                void const* src, size_t srcSize,
554                                unsigned lastBlock) {
555     ZSTD_entropyCTablesMetadata_t entropyMetadata;
556 
557     FORWARD_IF_ERROR(ZSTD_buildBlockEntropyStats(&zc->seqStore,
558           &zc->blockState.prevCBlock->entropy,
559           &zc->blockState.nextCBlock->entropy,
560           &zc->appliedParams,
561           &entropyMetadata,
562           zc->entropyWorkspace, ENTROPY_WORKSPACE_SIZE /* statically allocated in resetCCtx */), "");
563 
564     return ZSTD_compressSubBlock_multi(&zc->seqStore,
565             zc->blockState.prevCBlock,
566             zc->blockState.nextCBlock,
567             &entropyMetadata,
568             &zc->appliedParams,
569             dst, dstCapacity,
570             src, srcSize,
571             zc->bmi2, lastBlock,
572             zc->entropyWorkspace, ENTROPY_WORKSPACE_SIZE /* statically allocated in resetCCtx */);
573 }
574