xref: /freebsd/sys/contrib/zstd/lib/legacy/zstd_v04.c (revision 18054d0220cfc8df9c9568c437bd6fbb59d53c3c)
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  /******************************************
13  *  Includes
14  ******************************************/
15 #include <stddef.h>    /* size_t, ptrdiff_t */
16 #include <string.h>    /* memcpy */
17 
18 #include "zstd_v04.h"
19 #include "../common/error_private.h"
20 
21 
22 /* ******************************************************************
23  *   mem.h
24  *******************************************************************/
25 #ifndef MEM_H_MODULE
26 #define MEM_H_MODULE
27 
28 #if defined (__cplusplus)
29 extern "C" {
30 #endif
31 
32 
33 /******************************************
34 *  Compiler-specific
35 ******************************************/
36 #if defined(_MSC_VER)   /* Visual Studio */
37 #   include <stdlib.h>  /* _byteswap_ulong */
38 #   include <intrin.h>  /* _byteswap_* */
39 #endif
40 #if defined(__GNUC__)
41 #  define MEM_STATIC static __attribute__((unused))
42 #elif defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
43 #  define MEM_STATIC static inline
44 #elif defined(_MSC_VER)
45 #  define MEM_STATIC static __inline
46 #else
47 #  define MEM_STATIC static  /* this version may generate warnings for unused static functions; disable the relevant warning */
48 #endif
49 
50 
51 /****************************************************************
52 *  Basic Types
53 *****************************************************************/
54 #if defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
55 # if defined(_AIX)
56 #  include <inttypes.h>
57 # else
58 #  include <stdint.h> /* intptr_t */
59 # endif
60   typedef  uint8_t BYTE;
61   typedef uint16_t U16;
62   typedef  int16_t S16;
63   typedef uint32_t U32;
64   typedef  int32_t S32;
65   typedef uint64_t U64;
66   typedef  int64_t S64;
67 #else
68   typedef unsigned char       BYTE;
69   typedef unsigned short      U16;
70   typedef   signed short      S16;
71   typedef unsigned int        U32;
72   typedef   signed int        S32;
73   typedef unsigned long long  U64;
74   typedef   signed long long  S64;
75 #endif
76 
77 
78 /*-*************************************
79 *  Debug
80 ***************************************/
81 #include "../common/debug.h"
82 #ifndef assert
83 #  define assert(condition) ((void)0)
84 #endif
85 
86 
87 /****************************************************************
88 *  Memory I/O
89 *****************************************************************/
90 /* MEM_FORCE_MEMORY_ACCESS
91  * By default, access to unaligned memory is controlled by `memcpy()`, which is safe and portable.
92  * Unfortunately, on some target/compiler combinations, the generated assembly is sub-optimal.
93  * The below switch allow to select different access method for improved performance.
94  * Method 0 (default) : use `memcpy()`. Safe and portable.
95  * Method 1 : `__packed` statement. It depends on compiler extension (ie, not portable).
96  *            This method is safe if your compiler supports it, and *generally* as fast or faster than `memcpy`.
97  * Method 2 : direct access. This method is portable but violate C standard.
98  *            It can generate buggy code on targets generating assembly depending on alignment.
99  *            But in some circumstances, it's the only known way to get the most performance (ie GCC + ARMv6)
100  * See http://fastcompression.blogspot.fr/2015/08/accessing-unaligned-memory.html for details.
101  * Prefer these methods in priority order (0 > 1 > 2)
102  */
103 #ifndef MEM_FORCE_MEMORY_ACCESS   /* can be defined externally, on command line for example */
104 #  if defined(__GNUC__) && ( defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__) )
105 #    define MEM_FORCE_MEMORY_ACCESS 2
106 #  elif (defined(__INTEL_COMPILER) && !defined(WIN32)) || \
107   (defined(__GNUC__) && ( defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7S__) ))
108 #    define MEM_FORCE_MEMORY_ACCESS 1
109 #  endif
110 #endif
111 
112 MEM_STATIC unsigned MEM_32bits(void) { return sizeof(void*)==4; }
113 MEM_STATIC unsigned MEM_64bits(void) { return sizeof(void*)==8; }
114 
115 MEM_STATIC unsigned MEM_isLittleEndian(void)
116 {
117     const union { U32 u; BYTE c[4]; } one = { 1 };   /* don't use static : performance detrimental  */
118     return one.c[0];
119 }
120 
121 #if defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==2)
122 
123 /* violates C standard on structure alignment.
124 Only use if no other choice to achieve best performance on target platform */
125 MEM_STATIC U16 MEM_read16(const void* memPtr) { return *(const U16*) memPtr; }
126 MEM_STATIC U32 MEM_read32(const void* memPtr) { return *(const U32*) memPtr; }
127 MEM_STATIC U64 MEM_read64(const void* memPtr) { return *(const U64*) memPtr; }
128 
129 MEM_STATIC void MEM_write16(void* memPtr, U16 value) { *(U16*)memPtr = value; }
130 
131 #elif defined(MEM_FORCE_MEMORY_ACCESS) && (MEM_FORCE_MEMORY_ACCESS==1)
132 
133 /* __pack instructions are safer, but compiler specific, hence potentially problematic for some compilers */
134 /* currently only defined for gcc and icc */
135 typedef union { U16 u16; U32 u32; U64 u64; } __attribute__((packed)) unalign;
136 
137 MEM_STATIC U16 MEM_read16(const void* ptr) { return ((const unalign*)ptr)->u16; }
138 MEM_STATIC U32 MEM_read32(const void* ptr) { return ((const unalign*)ptr)->u32; }
139 MEM_STATIC U64 MEM_read64(const void* ptr) { return ((const unalign*)ptr)->u64; }
140 
141 MEM_STATIC void MEM_write16(void* memPtr, U16 value) { ((unalign*)memPtr)->u16 = value; }
142 
143 #else
144 
145 /* default method, safe and standard.
146    can sometimes prove slower */
147 
148 MEM_STATIC U16 MEM_read16(const void* memPtr)
149 {
150     U16 val; memcpy(&val, memPtr, sizeof(val)); return val;
151 }
152 
153 MEM_STATIC U32 MEM_read32(const void* memPtr)
154 {
155     U32 val; memcpy(&val, memPtr, sizeof(val)); return val;
156 }
157 
158 MEM_STATIC U64 MEM_read64(const void* memPtr)
159 {
160     U64 val; memcpy(&val, memPtr, sizeof(val)); return val;
161 }
162 
163 MEM_STATIC void MEM_write16(void* memPtr, U16 value)
164 {
165     memcpy(memPtr, &value, sizeof(value));
166 }
167 
168 #endif /* MEM_FORCE_MEMORY_ACCESS */
169 
170 
171 MEM_STATIC U16 MEM_readLE16(const void* memPtr)
172 {
173     if (MEM_isLittleEndian())
174         return MEM_read16(memPtr);
175     else
176     {
177         const BYTE* p = (const BYTE*)memPtr;
178         return (U16)(p[0] + (p[1]<<8));
179     }
180 }
181 
182 MEM_STATIC void MEM_writeLE16(void* memPtr, U16 val)
183 {
184     if (MEM_isLittleEndian())
185     {
186         MEM_write16(memPtr, val);
187     }
188     else
189     {
190         BYTE* p = (BYTE*)memPtr;
191         p[0] = (BYTE)val;
192         p[1] = (BYTE)(val>>8);
193     }
194 }
195 
196 MEM_STATIC U32 MEM_readLE24(const void* memPtr)
197 {
198     return MEM_readLE16(memPtr) + (((const BYTE*)memPtr)[2] << 16);
199 }
200 
201 MEM_STATIC U32 MEM_readLE32(const void* memPtr)
202 {
203     if (MEM_isLittleEndian())
204         return MEM_read32(memPtr);
205     else
206     {
207         const BYTE* p = (const BYTE*)memPtr;
208         return (U32)((U32)p[0] + ((U32)p[1]<<8) + ((U32)p[2]<<16) + ((U32)p[3]<<24));
209     }
210 }
211 
212 
213 MEM_STATIC U64 MEM_readLE64(const void* memPtr)
214 {
215     if (MEM_isLittleEndian())
216         return MEM_read64(memPtr);
217     else
218     {
219         const BYTE* p = (const BYTE*)memPtr;
220         return (U64)((U64)p[0] + ((U64)p[1]<<8) + ((U64)p[2]<<16) + ((U64)p[3]<<24)
221                      + ((U64)p[4]<<32) + ((U64)p[5]<<40) + ((U64)p[6]<<48) + ((U64)p[7]<<56));
222     }
223 }
224 
225 
226 MEM_STATIC size_t MEM_readLEST(const void* memPtr)
227 {
228     if (MEM_32bits())
229         return (size_t)MEM_readLE32(memPtr);
230     else
231         return (size_t)MEM_readLE64(memPtr);
232 }
233 
234 
235 #if defined (__cplusplus)
236 }
237 #endif
238 
239 #endif /* MEM_H_MODULE */
240 
241 /*
242     zstd - standard compression library
243     Header File for static linking only
244 */
245 #ifndef ZSTD_STATIC_H
246 #define ZSTD_STATIC_H
247 
248 
249 /* *************************************
250 *  Types
251 ***************************************/
252 #define ZSTD_WINDOWLOG_ABSOLUTEMIN 11
253 
254 /** from faster to stronger */
255 typedef enum { ZSTD_fast, ZSTD_greedy, ZSTD_lazy, ZSTD_lazy2, ZSTD_btlazy2 } ZSTD_strategy;
256 
257 typedef struct
258 {
259     U64 srcSize;       /* optional : tells how much bytes are present in the frame. Use 0 if not known. */
260     U32 windowLog;     /* largest match distance : larger == more compression, more memory needed during decompression */
261     U32 contentLog;    /* full search segment : larger == more compression, slower, more memory (useless for fast) */
262     U32 hashLog;       /* dispatch table : larger == more memory, faster */
263     U32 searchLog;     /* nb of searches : larger == more compression, slower */
264     U32 searchLength;  /* size of matches : larger == faster decompression, sometimes less compression */
265     ZSTD_strategy strategy;
266 } ZSTD_parameters;
267 
268 typedef ZSTDv04_Dctx ZSTD_DCtx;
269 
270 /* *************************************
271 *  Advanced functions
272 ***************************************/
273 /** ZSTD_decompress_usingDict
274 *   Same as ZSTD_decompressDCtx, using a Dictionary content as prefix
275 *   Note : dict can be NULL, in which case, it's equivalent to ZSTD_decompressDCtx() */
276 static size_t ZSTD_decompress_usingDict(ZSTD_DCtx* ctx,
277                                              void* dst, size_t maxDstSize,
278                                        const void* src, size_t srcSize,
279                                        const void* dict,size_t dictSize);
280 
281 
282 /* **************************************
283 *  Streaming functions (direct mode)
284 ****************************************/
285 static size_t ZSTD_resetDCtx(ZSTD_DCtx* dctx);
286 static size_t ZSTD_getFrameParams(ZSTD_parameters* params, const void* src, size_t srcSize);
287 static void   ZSTD_decompress_insertDictionary(ZSTD_DCtx* ctx, const void* src, size_t srcSize);
288 
289 static size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx* dctx);
290 static size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize);
291 
292 /**
293   Streaming decompression, bufferless mode
294 
295   A ZSTD_DCtx object is required to track streaming operations.
296   Use ZSTD_createDCtx() / ZSTD_freeDCtx() to manage it.
297   A ZSTD_DCtx object can be re-used multiple times. Use ZSTD_resetDCtx() to return to fresh status.
298 
299   First operation is to retrieve frame parameters, using ZSTD_getFrameParams().
300   This function doesn't consume its input. It needs enough input data to properly decode the frame header.
301   Objective is to retrieve *params.windowlog, to know minimum amount of memory required during decoding.
302   Result : 0 when successful, it means the ZSTD_parameters structure has been filled.
303            >0 : means there is not enough data into src. Provides the expected size to successfully decode header.
304            errorCode, which can be tested using ZSTD_isError() (For example, if it's not a ZSTD header)
305 
306   Then, you can optionally insert a dictionary.
307   This operation must mimic the compressor behavior, otherwise decompression will fail or be corrupted.
308 
309   Then it's possible to start decompression.
310   Use ZSTD_nextSrcSizeToDecompress() and ZSTD_decompressContinue() alternatively.
311   ZSTD_nextSrcSizeToDecompress() tells how much bytes to provide as 'srcSize' to ZSTD_decompressContinue().
312   ZSTD_decompressContinue() requires this exact amount of bytes, or it will fail.
313   ZSTD_decompressContinue() needs previous data blocks during decompression, up to (1 << windowlog).
314   They should preferably be located contiguously, prior to current block. Alternatively, a round buffer is also possible.
315 
316   @result of ZSTD_decompressContinue() is the number of bytes regenerated within 'dst'.
317   It can be zero, which is not an error; it just means ZSTD_decompressContinue() has decoded some header.
318 
319   A frame is fully decoded when ZSTD_nextSrcSizeToDecompress() returns zero.
320   Context can then be reset to start a new decompression.
321 */
322 
323 
324 
325 
326 #endif  /* ZSTD_STATIC_H */
327 
328 
329 /*
330     zstd_internal - common functions to include
331     Header File for include
332 */
333 #ifndef ZSTD_CCOMMON_H_MODULE
334 #define ZSTD_CCOMMON_H_MODULE
335 
336 /* *************************************
337 *  Common macros
338 ***************************************/
339 #define MIN(a,b) ((a)<(b) ? (a) : (b))
340 #define MAX(a,b) ((a)>(b) ? (a) : (b))
341 
342 
343 /* *************************************
344 *  Common constants
345 ***************************************/
346 #define ZSTD_MAGICNUMBER 0xFD2FB524   /* v0.4 */
347 
348 #define KB *(1 <<10)
349 #define MB *(1 <<20)
350 #define GB *(1U<<30)
351 
352 #define BLOCKSIZE (128 KB)                 /* define, for static allocation */
353 
354 static const size_t ZSTD_blockHeaderSize = 3;
355 static const size_t ZSTD_frameHeaderSize_min = 5;
356 #define ZSTD_frameHeaderSize_max 5         /* define, for static allocation */
357 
358 #define BIT7 128
359 #define BIT6  64
360 #define BIT5  32
361 #define BIT4  16
362 #define BIT1   2
363 #define BIT0   1
364 
365 #define IS_RAW BIT0
366 #define IS_RLE BIT1
367 
368 #define MINMATCH 4
369 #define REPCODE_STARTVALUE 4
370 
371 #define MLbits   7
372 #define LLbits   6
373 #define Offbits  5
374 #define MaxML  ((1<<MLbits) - 1)
375 #define MaxLL  ((1<<LLbits) - 1)
376 #define MaxOff ((1<<Offbits)- 1)
377 #define MLFSELog   10
378 #define LLFSELog   10
379 #define OffFSELog   9
380 #define MaxSeq MAX(MaxLL, MaxML)
381 
382 #define MIN_SEQUENCES_SIZE (2 /*seqNb*/ + 2 /*dumps*/ + 3 /*seqTables*/ + 1 /*bitStream*/)
383 #define MIN_CBLOCK_SIZE (3 /*litCSize*/ + MIN_SEQUENCES_SIZE)
384 
385 #define ZSTD_CONTENTSIZE_ERROR   (0ULL - 2)
386 
387 typedef enum { bt_compressed, bt_raw, bt_rle, bt_end } blockType_t;
388 
389 
390 /* ******************************************
391 *  Shared functions to include for inlining
392 ********************************************/
393 static void ZSTD_copy8(void* dst, const void* src) { memcpy(dst, src, 8); }
394 
395 #define COPY8(d,s) { ZSTD_copy8(d,s); d+=8; s+=8; }
396 
397 /*! ZSTD_wildcopy : custom version of memcpy(), can copy up to 7-8 bytes too many */
398 static void ZSTD_wildcopy(void* dst, const void* src, ptrdiff_t length)
399 {
400     const BYTE* ip = (const BYTE*)src;
401     BYTE* op = (BYTE*)dst;
402     BYTE* const oend = op + length;
403     do
404         COPY8(op, ip)
405     while (op < oend);
406 }
407 
408 
409 
410 /* ******************************************************************
411    FSE : Finite State Entropy coder
412    header file
413 ****************************************************************** */
414 #ifndef FSE_H
415 #define FSE_H
416 
417 #if defined (__cplusplus)
418 extern "C" {
419 #endif
420 
421 
422 /* *****************************************
423 *  Includes
424 ******************************************/
425 #include <stddef.h>    /* size_t, ptrdiff_t */
426 
427 
428 /* *****************************************
429 *  FSE simple functions
430 ******************************************/
431 static size_t FSE_decompress(void* dst,  size_t maxDstSize,
432                 const void* cSrc, size_t cSrcSize);
433 /*!
434 FSE_decompress():
435     Decompress FSE data from buffer 'cSrc', of size 'cSrcSize',
436     into already allocated destination buffer 'dst', of size 'maxDstSize'.
437     return : size of regenerated data (<= maxDstSize)
438              or an error code, which can be tested using FSE_isError()
439 
440     ** Important ** : FSE_decompress() doesn't decompress non-compressible nor RLE data !!!
441     Why ? : making this distinction requires a header.
442     Header management is intentionally delegated to the user layer, which can better manage special cases.
443 */
444 
445 
446 /* *****************************************
447 *  Tool functions
448 ******************************************/
449 /* Error Management */
450 static unsigned    FSE_isError(size_t code);        /* tells if a return value is an error code */
451 
452 
453 
454 /* *****************************************
455 *  FSE detailed API
456 ******************************************/
457 /*!
458 FSE_compress() does the following:
459 1. count symbol occurrence from source[] into table count[]
460 2. normalize counters so that sum(count[]) == Power_of_2 (2^tableLog)
461 3. save normalized counters to memory buffer using writeNCount()
462 4. build encoding table 'CTable' from normalized counters
463 5. encode the data stream using encoding table 'CTable'
464 
465 FSE_decompress() does the following:
466 1. read normalized counters with readNCount()
467 2. build decoding table 'DTable' from normalized counters
468 3. decode the data stream using decoding table 'DTable'
469 
470 The following API allows targeting specific sub-functions for advanced tasks.
471 For example, it's possible to compress several blocks using the same 'CTable',
472 or to save and provide normalized distribution using external method.
473 */
474 
475 
476 /* *** DECOMPRESSION *** */
477 
478 /*!
479 FSE_readNCount():
480    Read compactly saved 'normalizedCounter' from 'rBuffer'.
481    return : size read from 'rBuffer'
482             or an errorCode, which can be tested using FSE_isError()
483             maxSymbolValuePtr[0] and tableLogPtr[0] will also be updated with their respective values */
484 static  size_t FSE_readNCount (short* normalizedCounter, unsigned* maxSymbolValuePtr, unsigned* tableLogPtr, const void* rBuffer, size_t rBuffSize);
485 
486 /*!
487 Constructor and Destructor of type FSE_DTable
488     Note that its size depends on 'tableLog' */
489 typedef unsigned FSE_DTable;   /* don't allocate that. It's just a way to be more restrictive than void* */
490 
491 /*!
492 FSE_buildDTable():
493    Builds 'dt', which must be already allocated, using FSE_createDTable()
494    return : 0,
495             or an errorCode, which can be tested using FSE_isError() */
496 static size_t FSE_buildDTable ( FSE_DTable* dt, const short* normalizedCounter, unsigned maxSymbolValue, unsigned tableLog);
497 
498 /*!
499 FSE_decompress_usingDTable():
500    Decompress compressed source 'cSrc' of size 'cSrcSize' using 'dt'
501    into 'dst' which must be already allocated.
502    return : size of regenerated data (necessarily <= maxDstSize)
503             or an errorCode, which can be tested using FSE_isError() */
504 static  size_t FSE_decompress_usingDTable(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const FSE_DTable* dt);
505 
506 /*!
507 Tutorial :
508 ----------
509 (Note : these functions only decompress FSE-compressed blocks.
510  If block is uncompressed, use memcpy() instead
511  If block is a single repeated byte, use memset() instead )
512 
513 The first step is to obtain the normalized frequencies of symbols.
514 This can be performed by FSE_readNCount() if it was saved using FSE_writeNCount().
515 'normalizedCounter' must be already allocated, and have at least 'maxSymbolValuePtr[0]+1' cells of signed short.
516 In practice, that means it's necessary to know 'maxSymbolValue' beforehand,
517 or size the table to handle worst case situations (typically 256).
518 FSE_readNCount() will provide 'tableLog' and 'maxSymbolValue'.
519 The result of FSE_readNCount() is the number of bytes read from 'rBuffer'.
520 Note that 'rBufferSize' must be at least 4 bytes, even if useful information is less than that.
521 If there is an error, the function will return an error code, which can be tested using FSE_isError().
522 
523 The next step is to build the decompression tables 'FSE_DTable' from 'normalizedCounter'.
524 This is performed by the function FSE_buildDTable().
525 The space required by 'FSE_DTable' must be already allocated using FSE_createDTable().
526 If there is an error, the function will return an error code, which can be tested using FSE_isError().
527 
528 'FSE_DTable' can then be used to decompress 'cSrc', with FSE_decompress_usingDTable().
529 'cSrcSize' must be strictly correct, otherwise decompression will fail.
530 FSE_decompress_usingDTable() result will tell how many bytes were regenerated (<=maxDstSize).
531 If there is an error, the function will return an error code, which can be tested using FSE_isError(). (ex: dst buffer too small)
532 */
533 
534 
535 #if defined (__cplusplus)
536 }
537 #endif
538 
539 #endif  /* FSE_H */
540 
541 
542 /* ******************************************************************
543    bitstream
544    Part of NewGen Entropy library
545    header file (to include)
546    Copyright (C) 2013-2015, Yann Collet.
547 
548    BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
549 
550    Redistribution and use in source and binary forms, with or without
551    modification, are permitted provided that the following conditions are
552    met:
553 
554        * Redistributions of source code must retain the above copyright
555    notice, this list of conditions and the following disclaimer.
556        * Redistributions in binary form must reproduce the above
557    copyright notice, this list of conditions and the following disclaimer
558    in the documentation and/or other materials provided with the
559    distribution.
560 
561    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
562    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
563    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
564    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
565    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
566    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
567    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
568    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
569    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
570    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
571    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
572 
573    You can contact the author at :
574    - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
575    - Public forum : https://groups.google.com/forum/#!forum/lz4c
576 ****************************************************************** */
577 #ifndef BITSTREAM_H_MODULE
578 #define BITSTREAM_H_MODULE
579 
580 #if defined (__cplusplus)
581 extern "C" {
582 #endif
583 
584 
585 /*
586 *  This API consists of small unitary functions, which highly benefit from being inlined.
587 *  Since link-time-optimization is not available for all compilers,
588 *  these functions are defined into a .h to be included.
589 */
590 
591 /**********************************************
592 *  bitStream decompression API (read backward)
593 **********************************************/
594 typedef struct
595 {
596     size_t   bitContainer;
597     unsigned bitsConsumed;
598     const char* ptr;
599     const char* start;
600 } BIT_DStream_t;
601 
602 typedef enum { BIT_DStream_unfinished = 0,
603                BIT_DStream_endOfBuffer = 1,
604                BIT_DStream_completed = 2,
605                BIT_DStream_overflow = 3 } BIT_DStream_status;  /* result of BIT_reloadDStream() */
606                /* 1,2,4,8 would be better for bitmap combinations, but slows down performance a bit ... :( */
607 
608 MEM_STATIC size_t   BIT_initDStream(BIT_DStream_t* bitD, const void* srcBuffer, size_t srcSize);
609 MEM_STATIC size_t   BIT_readBits(BIT_DStream_t* bitD, unsigned nbBits);
610 MEM_STATIC BIT_DStream_status BIT_reloadDStream(BIT_DStream_t* bitD);
611 MEM_STATIC unsigned BIT_endOfDStream(const BIT_DStream_t* bitD);
612 
613 
614 
615 
616 /******************************************
617 *  unsafe API
618 ******************************************/
619 MEM_STATIC size_t BIT_readBitsFast(BIT_DStream_t* bitD, unsigned nbBits);
620 /* faster, but works only if nbBits >= 1 */
621 
622 
623 
624 /****************************************************************
625 *  Helper functions
626 ****************************************************************/
627 MEM_STATIC unsigned BIT_highbit32 (U32 val)
628 {
629 #   if defined(_MSC_VER)   /* Visual */
630     unsigned long r=0;
631     _BitScanReverse ( &r, val );
632     return (unsigned) r;
633 #   elif defined(__GNUC__) && (__GNUC__ >= 3)   /* Use GCC Intrinsic */
634     return __builtin_clz (val) ^ 31;
635 #   else   /* Software version */
636     static const unsigned DeBruijnClz[32] = { 0, 9, 1, 10, 13, 21, 2, 29, 11, 14, 16, 18, 22, 25, 3, 30, 8, 12, 20, 28, 15, 17, 24, 7, 19, 27, 23, 6, 26, 5, 4, 31 };
637     U32 v = val;
638     unsigned r;
639     v |= v >> 1;
640     v |= v >> 2;
641     v |= v >> 4;
642     v |= v >> 8;
643     v |= v >> 16;
644     r = DeBruijnClz[ (U32) (v * 0x07C4ACDDU) >> 27];
645     return r;
646 #   endif
647 }
648 
649 
650 /**********************************************************
651 * bitStream decoding
652 **********************************************************/
653 
654 /*!BIT_initDStream
655 *  Initialize a BIT_DStream_t.
656 *  @bitD : a pointer to an already allocated BIT_DStream_t structure
657 *  @srcBuffer must point at the beginning of a bitStream
658 *  @srcSize must be the exact size of the bitStream
659 *  @result : size of stream (== srcSize) or an errorCode if a problem is detected
660 */
661 MEM_STATIC size_t BIT_initDStream(BIT_DStream_t* bitD, const void* srcBuffer, size_t srcSize)
662 {
663     if (srcSize < 1) { memset(bitD, 0, sizeof(*bitD)); return ERROR(srcSize_wrong); }
664 
665     if (srcSize >=  sizeof(size_t))   /* normal case */
666     {
667         U32 contain32;
668         bitD->start = (const char*)srcBuffer;
669         bitD->ptr   = (const char*)srcBuffer + srcSize - sizeof(size_t);
670         bitD->bitContainer = MEM_readLEST(bitD->ptr);
671         contain32 = ((const BYTE*)srcBuffer)[srcSize-1];
672         if (contain32 == 0) return ERROR(GENERIC);   /* endMark not present */
673         bitD->bitsConsumed = 8 - BIT_highbit32(contain32);
674     }
675     else
676     {
677         U32 contain32;
678         bitD->start = (const char*)srcBuffer;
679         bitD->ptr   = bitD->start;
680         bitD->bitContainer = *(const BYTE*)(bitD->start);
681         switch(srcSize)
682         {
683             case 7: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[6]) << (sizeof(size_t)*8 - 16);/* fall-through */
684             case 6: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[5]) << (sizeof(size_t)*8 - 24);/* fall-through */
685             case 5: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[4]) << (sizeof(size_t)*8 - 32);/* fall-through */
686             case 4: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[3]) << 24; /* fall-through */
687             case 3: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[2]) << 16; /* fall-through */
688             case 2: bitD->bitContainer += (size_t)(((const BYTE*)(bitD->start))[1]) <<  8; /* fall-through */
689             default: break;
690         }
691         contain32 = ((const BYTE*)srcBuffer)[srcSize-1];
692         if (contain32 == 0) return ERROR(GENERIC);   /* endMark not present */
693         bitD->bitsConsumed = 8 - BIT_highbit32(contain32);
694         bitD->bitsConsumed += (U32)(sizeof(size_t) - srcSize)*8;
695     }
696 
697     return srcSize;
698 }
699 
700 MEM_STATIC size_t BIT_lookBits(BIT_DStream_t* bitD, U32 nbBits)
701 {
702     const U32 bitMask = sizeof(bitD->bitContainer)*8 - 1;
703     return ((bitD->bitContainer << (bitD->bitsConsumed & bitMask)) >> 1) >> ((bitMask-nbBits) & bitMask);
704 }
705 
706 /*! BIT_lookBitsFast :
707 *   unsafe version; only works only if nbBits >= 1 */
708 MEM_STATIC size_t BIT_lookBitsFast(BIT_DStream_t* bitD, U32 nbBits)
709 {
710     const U32 bitMask = sizeof(bitD->bitContainer)*8 - 1;
711     return (bitD->bitContainer << (bitD->bitsConsumed & bitMask)) >> (((bitMask+1)-nbBits) & bitMask);
712 }
713 
714 MEM_STATIC void BIT_skipBits(BIT_DStream_t* bitD, U32 nbBits)
715 {
716     bitD->bitsConsumed += nbBits;
717 }
718 
719 MEM_STATIC size_t BIT_readBits(BIT_DStream_t* bitD, U32 nbBits)
720 {
721     size_t value = BIT_lookBits(bitD, nbBits);
722     BIT_skipBits(bitD, nbBits);
723     return value;
724 }
725 
726 /*!BIT_readBitsFast :
727 *  unsafe version; only works only if nbBits >= 1 */
728 MEM_STATIC size_t BIT_readBitsFast(BIT_DStream_t* bitD, U32 nbBits)
729 {
730     size_t value = BIT_lookBitsFast(bitD, nbBits);
731     BIT_skipBits(bitD, nbBits);
732     return value;
733 }
734 
735 MEM_STATIC BIT_DStream_status BIT_reloadDStream(BIT_DStream_t* bitD)
736 {
737     if (bitD->bitsConsumed > (sizeof(bitD->bitContainer)*8))  /* should never happen */
738         return BIT_DStream_overflow;
739 
740     if (bitD->ptr >= bitD->start + sizeof(bitD->bitContainer))
741     {
742         bitD->ptr -= bitD->bitsConsumed >> 3;
743         bitD->bitsConsumed &= 7;
744         bitD->bitContainer = MEM_readLEST(bitD->ptr);
745         return BIT_DStream_unfinished;
746     }
747     if (bitD->ptr == bitD->start)
748     {
749         if (bitD->bitsConsumed < sizeof(bitD->bitContainer)*8) return BIT_DStream_endOfBuffer;
750         return BIT_DStream_completed;
751     }
752     {
753         U32 nbBytes = bitD->bitsConsumed >> 3;
754         BIT_DStream_status result = BIT_DStream_unfinished;
755         if (bitD->ptr - nbBytes < bitD->start)
756         {
757             nbBytes = (U32)(bitD->ptr - bitD->start);  /* ptr > start */
758             result = BIT_DStream_endOfBuffer;
759         }
760         bitD->ptr -= nbBytes;
761         bitD->bitsConsumed -= nbBytes*8;
762         bitD->bitContainer = MEM_readLEST(bitD->ptr);   /* reminder : srcSize > sizeof(bitD) */
763         return result;
764     }
765 }
766 
767 /*! BIT_endOfDStream
768 *   @return Tells if DStream has reached its exact end
769 */
770 MEM_STATIC unsigned BIT_endOfDStream(const BIT_DStream_t* DStream)
771 {
772     return ((DStream->ptr == DStream->start) && (DStream->bitsConsumed == sizeof(DStream->bitContainer)*8));
773 }
774 
775 #if defined (__cplusplus)
776 }
777 #endif
778 
779 #endif /* BITSTREAM_H_MODULE */
780 
781 
782 
783 /* ******************************************************************
784    FSE : Finite State Entropy coder
785    header file for static linking (only)
786    Copyright (C) 2013-2015, Yann Collet
787 
788    BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
789 
790    Redistribution and use in source and binary forms, with or without
791    modification, are permitted provided that the following conditions are
792    met:
793 
794        * Redistributions of source code must retain the above copyright
795    notice, this list of conditions and the following disclaimer.
796        * Redistributions in binary form must reproduce the above
797    copyright notice, this list of conditions and the following disclaimer
798    in the documentation and/or other materials provided with the
799    distribution.
800 
801    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
802    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
803    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
804    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
805    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
806    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
807    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
808    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
809    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
810    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
811    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
812 
813    You can contact the author at :
814    - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
815    - Public forum : https://groups.google.com/forum/#!forum/lz4c
816 ****************************************************************** */
817 #ifndef FSE_STATIC_H
818 #define FSE_STATIC_H
819 
820 #if defined (__cplusplus)
821 extern "C" {
822 #endif
823 
824 
825 /* *****************************************
826 *  Static allocation
827 *******************************************/
828 /* FSE buffer bounds */
829 #define FSE_NCOUNTBOUND 512
830 #define FSE_BLOCKBOUND(size) (size + (size>>7))
831 #define FSE_COMPRESSBOUND(size) (FSE_NCOUNTBOUND + FSE_BLOCKBOUND(size))   /* Macro version, useful for static allocation */
832 
833 /* It is possible to statically allocate FSE CTable/DTable as a table of unsigned using below macros */
834 #define FSE_CTABLE_SIZE_U32(maxTableLog, maxSymbolValue)   (1 + (1<<(maxTableLog-1)) + ((maxSymbolValue+1)*2))
835 #define FSE_DTABLE_SIZE_U32(maxTableLog)                   (1 + (1<<maxTableLog))
836 
837 
838 /* *****************************************
839 *  FSE advanced API
840 *******************************************/
841 static size_t FSE_buildDTable_raw (FSE_DTable* dt, unsigned nbBits);
842 /* build a fake FSE_DTable, designed to read an uncompressed bitstream where each symbol uses nbBits */
843 
844 static size_t FSE_buildDTable_rle (FSE_DTable* dt, unsigned char symbolValue);
845 /* build a fake FSE_DTable, designed to always generate the same symbolValue */
846 
847 
848 
849 /* *****************************************
850 *  FSE symbol decompression API
851 *******************************************/
852 typedef struct
853 {
854     size_t      state;
855     const void* table;   /* precise table may vary, depending on U16 */
856 } FSE_DState_t;
857 
858 
859 static void     FSE_initDState(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD, const FSE_DTable* dt);
860 
861 static unsigned char FSE_decodeSymbol(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD);
862 
863 static unsigned FSE_endOfDState(const FSE_DState_t* DStatePtr);
864 
865 
866 /* *****************************************
867 *  FSE unsafe API
868 *******************************************/
869 static unsigned char FSE_decodeSymbolFast(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD);
870 /* faster, but works only if nbBits is always >= 1 (otherwise, result will be corrupted) */
871 
872 
873 /* *****************************************
874 *  Implementation of inlined functions
875 *******************************************/
876 /* decompression */
877 
878 typedef struct {
879     U16 tableLog;
880     U16 fastMode;
881 } FSE_DTableHeader;   /* sizeof U32 */
882 
883 typedef struct
884 {
885     unsigned short newState;
886     unsigned char  symbol;
887     unsigned char  nbBits;
888 } FSE_decode_t;   /* size == U32 */
889 
890 MEM_STATIC void FSE_initDState(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD, const FSE_DTable* dt)
891 {
892     FSE_DTableHeader DTableH;
893     memcpy(&DTableH, dt, sizeof(DTableH));
894     DStatePtr->state = BIT_readBits(bitD, DTableH.tableLog);
895     BIT_reloadDStream(bitD);
896     DStatePtr->table = dt + 1;
897 }
898 
899 MEM_STATIC BYTE FSE_decodeSymbol(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD)
900 {
901     const FSE_decode_t DInfo = ((const FSE_decode_t*)(DStatePtr->table))[DStatePtr->state];
902     const U32  nbBits = DInfo.nbBits;
903     BYTE symbol = DInfo.symbol;
904     size_t lowBits = BIT_readBits(bitD, nbBits);
905 
906     DStatePtr->state = DInfo.newState + lowBits;
907     return symbol;
908 }
909 
910 MEM_STATIC BYTE FSE_decodeSymbolFast(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD)
911 {
912     const FSE_decode_t DInfo = ((const FSE_decode_t*)(DStatePtr->table))[DStatePtr->state];
913     const U32 nbBits = DInfo.nbBits;
914     BYTE symbol = DInfo.symbol;
915     size_t lowBits = BIT_readBitsFast(bitD, nbBits);
916 
917     DStatePtr->state = DInfo.newState + lowBits;
918     return symbol;
919 }
920 
921 MEM_STATIC unsigned FSE_endOfDState(const FSE_DState_t* DStatePtr)
922 {
923     return DStatePtr->state == 0;
924 }
925 
926 
927 #if defined (__cplusplus)
928 }
929 #endif
930 
931 #endif  /* FSE_STATIC_H */
932 
933 /* ******************************************************************
934    FSE : Finite State Entropy coder
935    Copyright (C) 2013-2015, Yann Collet.
936 
937    BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
938 
939    Redistribution and use in source and binary forms, with or without
940    modification, are permitted provided that the following conditions are
941    met:
942 
943        * Redistributions of source code must retain the above copyright
944    notice, this list of conditions and the following disclaimer.
945        * Redistributions in binary form must reproduce the above
946    copyright notice, this list of conditions and the following disclaimer
947    in the documentation and/or other materials provided with the
948    distribution.
949 
950    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
951    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
952    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
953    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
954    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
955    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
956    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
957    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
958    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
959    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
960    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
961 
962     You can contact the author at :
963     - FSE source repository : https://github.com/Cyan4973/FiniteStateEntropy
964     - Public forum : https://groups.google.com/forum/#!forum/lz4c
965 ****************************************************************** */
966 
967 #ifndef FSE_COMMONDEFS_ONLY
968 
969 /* **************************************************************
970 *  Tuning parameters
971 ****************************************************************/
972 /*!MEMORY_USAGE :
973 *  Memory usage formula : N->2^N Bytes (examples : 10 -> 1KB; 12 -> 4KB ; 16 -> 64KB; 20 -> 1MB; etc.)
974 *  Increasing memory usage improves compression ratio
975 *  Reduced memory usage can improve speed, due to cache effect
976 *  Recommended max value is 14, for 16KB, which nicely fits into Intel x86 L1 cache */
977 #define FSE_MAX_MEMORY_USAGE 14
978 #define FSE_DEFAULT_MEMORY_USAGE 13
979 
980 /*!FSE_MAX_SYMBOL_VALUE :
981 *  Maximum symbol value authorized.
982 *  Required for proper stack allocation */
983 #define FSE_MAX_SYMBOL_VALUE 255
984 
985 
986 /* **************************************************************
987 *  template functions type & suffix
988 ****************************************************************/
989 #define FSE_FUNCTION_TYPE BYTE
990 #define FSE_FUNCTION_EXTENSION
991 #define FSE_DECODE_TYPE FSE_decode_t
992 
993 
994 #endif   /* !FSE_COMMONDEFS_ONLY */
995 
996 /* **************************************************************
997 *  Compiler specifics
998 ****************************************************************/
999 #ifdef _MSC_VER    /* Visual Studio */
1000 #  define FORCE_INLINE static __forceinline
1001 #  include <intrin.h>                    /* For Visual 2005 */
1002 #  pragma warning(disable : 4127)        /* disable: C4127: conditional expression is constant */
1003 #  pragma warning(disable : 4214)        /* disable: C4214: non-int bitfields */
1004 #else
1005 #  if defined (__cplusplus) || defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   /* C99 */
1006 #    ifdef __GNUC__
1007 #      define FORCE_INLINE static inline __attribute__((always_inline))
1008 #    else
1009 #      define FORCE_INLINE static inline
1010 #    endif
1011 #  else
1012 #    define FORCE_INLINE static
1013 #  endif /* __STDC_VERSION__ */
1014 #endif
1015 
1016 
1017 /* **************************************************************
1018 *  Dependencies
1019 ****************************************************************/
1020 #include <stdlib.h>     /* malloc, free, qsort */
1021 #include <string.h>     /* memcpy, memset */
1022 #include <stdio.h>      /* printf (debug) */
1023 
1024 
1025 /* ***************************************************************
1026 *  Constants
1027 *****************************************************************/
1028 #define FSE_MAX_TABLELOG  (FSE_MAX_MEMORY_USAGE-2)
1029 #define FSE_MAX_TABLESIZE (1U<<FSE_MAX_TABLELOG)
1030 #define FSE_MAXTABLESIZE_MASK (FSE_MAX_TABLESIZE-1)
1031 #define FSE_DEFAULT_TABLELOG (FSE_DEFAULT_MEMORY_USAGE-2)
1032 #define FSE_MIN_TABLELOG 5
1033 
1034 #define FSE_TABLELOG_ABSOLUTE_MAX 15
1035 #if FSE_MAX_TABLELOG > FSE_TABLELOG_ABSOLUTE_MAX
1036 #error "FSE_MAX_TABLELOG > FSE_TABLELOG_ABSOLUTE_MAX is not supported"
1037 #endif
1038 
1039 
1040 /* **************************************************************
1041 *  Error Management
1042 ****************************************************************/
1043 #define FSE_STATIC_ASSERT(c) { enum { FSE_static_assert = 1/(int)(!!(c)) }; }   /* use only *after* variable declarations */
1044 
1045 
1046 /* **************************************************************
1047 *  Complex types
1048 ****************************************************************/
1049 typedef U32 DTable_max_t[FSE_DTABLE_SIZE_U32(FSE_MAX_TABLELOG)];
1050 
1051 
1052 /*-**************************************************************
1053 *  Templates
1054 ****************************************************************/
1055 /*
1056   designed to be included
1057   for type-specific functions (template emulation in C)
1058   Objective is to write these functions only once, for improved maintenance
1059 */
1060 
1061 /* safety checks */
1062 #ifndef FSE_FUNCTION_EXTENSION
1063 #  error "FSE_FUNCTION_EXTENSION must be defined"
1064 #endif
1065 #ifndef FSE_FUNCTION_TYPE
1066 #  error "FSE_FUNCTION_TYPE must be defined"
1067 #endif
1068 
1069 /* Function names */
1070 #define FSE_CAT(X,Y) X##Y
1071 #define FSE_FUNCTION_NAME(X,Y) FSE_CAT(X,Y)
1072 #define FSE_TYPE_NAME(X,Y) FSE_CAT(X,Y)
1073 
1074 static U32 FSE_tableStep(U32 tableSize) { return (tableSize>>1) + (tableSize>>3) + 3; }
1075 
1076 
1077 static size_t FSE_buildDTable(FSE_DTable* dt, const short* normalizedCounter, unsigned maxSymbolValue, unsigned tableLog)
1078 {
1079     FSE_DTableHeader DTableH;
1080     void* const tdPtr = dt+1;   /* because dt is unsigned, 32-bits aligned on 32-bits */
1081     FSE_DECODE_TYPE* const tableDecode = (FSE_DECODE_TYPE*) (tdPtr);
1082     const U32 tableSize = 1 << tableLog;
1083     const U32 tableMask = tableSize-1;
1084     const U32 step = FSE_tableStep(tableSize);
1085     U16 symbolNext[FSE_MAX_SYMBOL_VALUE+1];
1086     U32 position = 0;
1087     U32 highThreshold = tableSize-1;
1088     const S16 largeLimit= (S16)(1 << (tableLog-1));
1089     U32 noLarge = 1;
1090     U32 s;
1091 
1092     /* Sanity Checks */
1093     if (maxSymbolValue > FSE_MAX_SYMBOL_VALUE) return ERROR(maxSymbolValue_tooLarge);
1094     if (tableLog > FSE_MAX_TABLELOG) return ERROR(tableLog_tooLarge);
1095 
1096     /* Init, lay down lowprob symbols */
1097     memset(tableDecode, 0, sizeof(FSE_DECODE_TYPE) * (maxSymbolValue+1) );   /* useless init, but keep static analyzer happy, and we don't need to performance optimize legacy decoders */
1098     DTableH.tableLog = (U16)tableLog;
1099     for (s=0; s<=maxSymbolValue; s++)
1100     {
1101         if (normalizedCounter[s]==-1)
1102         {
1103             tableDecode[highThreshold--].symbol = (FSE_FUNCTION_TYPE)s;
1104             symbolNext[s] = 1;
1105         }
1106         else
1107         {
1108             if (normalizedCounter[s] >= largeLimit) noLarge=0;
1109             symbolNext[s] = normalizedCounter[s];
1110         }
1111     }
1112 
1113     /* Spread symbols */
1114     for (s=0; s<=maxSymbolValue; s++)
1115     {
1116         int i;
1117         for (i=0; i<normalizedCounter[s]; i++)
1118         {
1119             tableDecode[position].symbol = (FSE_FUNCTION_TYPE)s;
1120             position = (position + step) & tableMask;
1121             while (position > highThreshold) position = (position + step) & tableMask;   /* lowprob area */
1122         }
1123     }
1124 
1125     if (position!=0) return ERROR(GENERIC);   /* position must reach all cells once, otherwise normalizedCounter is incorrect */
1126 
1127     /* Build Decoding table */
1128     {
1129         U32 i;
1130         for (i=0; i<tableSize; i++)
1131         {
1132             FSE_FUNCTION_TYPE symbol = (FSE_FUNCTION_TYPE)(tableDecode[i].symbol);
1133             U16 nextState = symbolNext[symbol]++;
1134             tableDecode[i].nbBits = (BYTE) (tableLog - BIT_highbit32 ((U32)nextState) );
1135             tableDecode[i].newState = (U16) ( (nextState << tableDecode[i].nbBits) - tableSize);
1136         }
1137     }
1138 
1139     DTableH.fastMode = (U16)noLarge;
1140     memcpy(dt, &DTableH, sizeof(DTableH));
1141     return 0;
1142 }
1143 
1144 
1145 #ifndef FSE_COMMONDEFS_ONLY
1146 /******************************************
1147 *  FSE helper functions
1148 ******************************************/
1149 static unsigned FSE_isError(size_t code) { return ERR_isError(code); }
1150 
1151 
1152 /****************************************************************
1153 *  FSE NCount encoding-decoding
1154 ****************************************************************/
1155 static short FSE_abs(short a)
1156 {
1157     return a<0 ? -a : a;
1158 }
1159 
1160 static size_t FSE_readNCount (short* normalizedCounter, unsigned* maxSVPtr, unsigned* tableLogPtr,
1161                  const void* headerBuffer, size_t hbSize)
1162 {
1163     const BYTE* const istart = (const BYTE*) headerBuffer;
1164     const BYTE* const iend = istart + hbSize;
1165     const BYTE* ip = istart;
1166     int nbBits;
1167     int remaining;
1168     int threshold;
1169     U32 bitStream;
1170     int bitCount;
1171     unsigned charnum = 0;
1172     int previous0 = 0;
1173 
1174     if (hbSize < 4) return ERROR(srcSize_wrong);
1175     bitStream = MEM_readLE32(ip);
1176     nbBits = (bitStream & 0xF) + FSE_MIN_TABLELOG;   /* extract tableLog */
1177     if (nbBits > FSE_TABLELOG_ABSOLUTE_MAX) return ERROR(tableLog_tooLarge);
1178     bitStream >>= 4;
1179     bitCount = 4;
1180     *tableLogPtr = nbBits;
1181     remaining = (1<<nbBits)+1;
1182     threshold = 1<<nbBits;
1183     nbBits++;
1184 
1185     while ((remaining>1) && (charnum<=*maxSVPtr))
1186     {
1187         if (previous0)
1188         {
1189             unsigned n0 = charnum;
1190             while ((bitStream & 0xFFFF) == 0xFFFF)
1191             {
1192                 n0+=24;
1193                 if (ip < iend-5)
1194                 {
1195                     ip+=2;
1196                     bitStream = MEM_readLE32(ip) >> bitCount;
1197                 }
1198                 else
1199                 {
1200                     bitStream >>= 16;
1201                     bitCount+=16;
1202                 }
1203             }
1204             while ((bitStream & 3) == 3)
1205             {
1206                 n0+=3;
1207                 bitStream>>=2;
1208                 bitCount+=2;
1209             }
1210             n0 += bitStream & 3;
1211             bitCount += 2;
1212             if (n0 > *maxSVPtr) return ERROR(maxSymbolValue_tooSmall);
1213             while (charnum < n0) normalizedCounter[charnum++] = 0;
1214             if ((ip <= iend-7) || (ip + (bitCount>>3) <= iend-4))
1215             {
1216                 ip += bitCount>>3;
1217                 bitCount &= 7;
1218                 bitStream = MEM_readLE32(ip) >> bitCount;
1219             }
1220             else
1221                 bitStream >>= 2;
1222         }
1223         {
1224             const short max = (short)((2*threshold-1)-remaining);
1225             short count;
1226 
1227             if ((bitStream & (threshold-1)) < (U32)max)
1228             {
1229                 count = (short)(bitStream & (threshold-1));
1230                 bitCount   += nbBits-1;
1231             }
1232             else
1233             {
1234                 count = (short)(bitStream & (2*threshold-1));
1235                 if (count >= threshold) count -= max;
1236                 bitCount   += nbBits;
1237             }
1238 
1239             count--;   /* extra accuracy */
1240             remaining -= FSE_abs(count);
1241             normalizedCounter[charnum++] = count;
1242             previous0 = !count;
1243             while (remaining < threshold)
1244             {
1245                 nbBits--;
1246                 threshold >>= 1;
1247             }
1248 
1249             {
1250                 if ((ip <= iend-7) || (ip + (bitCount>>3) <= iend-4))
1251                 {
1252                     ip += bitCount>>3;
1253                     bitCount &= 7;
1254                 }
1255                 else
1256                 {
1257                     bitCount -= (int)(8 * (iend - 4 - ip));
1258                     ip = iend - 4;
1259                 }
1260                 bitStream = MEM_readLE32(ip) >> (bitCount & 31);
1261             }
1262         }
1263     }
1264     if (remaining != 1) return ERROR(GENERIC);
1265     *maxSVPtr = charnum-1;
1266 
1267     ip += (bitCount+7)>>3;
1268     if ((size_t)(ip-istart) > hbSize) return ERROR(srcSize_wrong);
1269     return ip-istart;
1270 }
1271 
1272 
1273 /*********************************************************
1274 *  Decompression (Byte symbols)
1275 *********************************************************/
1276 static size_t FSE_buildDTable_rle (FSE_DTable* dt, BYTE symbolValue)
1277 {
1278     void* ptr = dt;
1279     FSE_DTableHeader* const DTableH = (FSE_DTableHeader*)ptr;
1280     void* dPtr = dt + 1;
1281     FSE_decode_t* const cell = (FSE_decode_t*)dPtr;
1282 
1283     DTableH->tableLog = 0;
1284     DTableH->fastMode = 0;
1285 
1286     cell->newState = 0;
1287     cell->symbol = symbolValue;
1288     cell->nbBits = 0;
1289 
1290     return 0;
1291 }
1292 
1293 
1294 static size_t FSE_buildDTable_raw (FSE_DTable* dt, unsigned nbBits)
1295 {
1296     void* ptr = dt;
1297     FSE_DTableHeader* const DTableH = (FSE_DTableHeader*)ptr;
1298     void* dPtr = dt + 1;
1299     FSE_decode_t* const dinfo = (FSE_decode_t*)dPtr;
1300     const unsigned tableSize = 1 << nbBits;
1301     const unsigned tableMask = tableSize - 1;
1302     const unsigned maxSymbolValue = tableMask;
1303     unsigned s;
1304 
1305     /* Sanity checks */
1306     if (nbBits < 1) return ERROR(GENERIC);         /* min size */
1307 
1308     /* Build Decoding Table */
1309     DTableH->tableLog = (U16)nbBits;
1310     DTableH->fastMode = 1;
1311     for (s=0; s<=maxSymbolValue; s++)
1312     {
1313         dinfo[s].newState = 0;
1314         dinfo[s].symbol = (BYTE)s;
1315         dinfo[s].nbBits = (BYTE)nbBits;
1316     }
1317 
1318     return 0;
1319 }
1320 
1321 FORCE_INLINE size_t FSE_decompress_usingDTable_generic(
1322           void* dst, size_t maxDstSize,
1323     const void* cSrc, size_t cSrcSize,
1324     const FSE_DTable* dt, const unsigned fast)
1325 {
1326     BYTE* const ostart = (BYTE*) dst;
1327     BYTE* op = ostart;
1328     BYTE* const omax = op + maxDstSize;
1329     BYTE* const olimit = omax-3;
1330 
1331     BIT_DStream_t bitD;
1332     FSE_DState_t state1;
1333     FSE_DState_t state2;
1334     size_t errorCode;
1335 
1336     /* Init */
1337     errorCode = BIT_initDStream(&bitD, cSrc, cSrcSize);   /* replaced last arg by maxCompressed Size */
1338     if (FSE_isError(errorCode)) return errorCode;
1339 
1340     FSE_initDState(&state1, &bitD, dt);
1341     FSE_initDState(&state2, &bitD, dt);
1342 
1343 #define FSE_GETSYMBOL(statePtr) fast ? FSE_decodeSymbolFast(statePtr, &bitD) : FSE_decodeSymbol(statePtr, &bitD)
1344 
1345     /* 4 symbols per loop */
1346     for ( ; (BIT_reloadDStream(&bitD)==BIT_DStream_unfinished) && (op<olimit) ; op+=4)
1347     {
1348         op[0] = FSE_GETSYMBOL(&state1);
1349 
1350         if (FSE_MAX_TABLELOG*2+7 > sizeof(bitD.bitContainer)*8)    /* This test must be static */
1351             BIT_reloadDStream(&bitD);
1352 
1353         op[1] = FSE_GETSYMBOL(&state2);
1354 
1355         if (FSE_MAX_TABLELOG*4+7 > sizeof(bitD.bitContainer)*8)    /* This test must be static */
1356             { if (BIT_reloadDStream(&bitD) > BIT_DStream_unfinished) { op+=2; break; } }
1357 
1358         op[2] = FSE_GETSYMBOL(&state1);
1359 
1360         if (FSE_MAX_TABLELOG*2+7 > sizeof(bitD.bitContainer)*8)    /* This test must be static */
1361             BIT_reloadDStream(&bitD);
1362 
1363         op[3] = FSE_GETSYMBOL(&state2);
1364     }
1365 
1366     /* tail */
1367     /* note : BIT_reloadDStream(&bitD) >= FSE_DStream_partiallyFilled; Ends at exactly BIT_DStream_completed */
1368     while (1)
1369     {
1370         if ( (BIT_reloadDStream(&bitD)>BIT_DStream_completed) || (op==omax) || (BIT_endOfDStream(&bitD) && (fast || FSE_endOfDState(&state1))) )
1371             break;
1372 
1373         *op++ = FSE_GETSYMBOL(&state1);
1374 
1375         if ( (BIT_reloadDStream(&bitD)>BIT_DStream_completed) || (op==omax) || (BIT_endOfDStream(&bitD) && (fast || FSE_endOfDState(&state2))) )
1376             break;
1377 
1378         *op++ = FSE_GETSYMBOL(&state2);
1379     }
1380 
1381     /* end ? */
1382     if (BIT_endOfDStream(&bitD) && FSE_endOfDState(&state1) && FSE_endOfDState(&state2))
1383         return op-ostart;
1384 
1385     if (op==omax) return ERROR(dstSize_tooSmall);   /* dst buffer is full, but cSrc unfinished */
1386 
1387     return ERROR(corruption_detected);
1388 }
1389 
1390 
1391 static size_t FSE_decompress_usingDTable(void* dst, size_t originalSize,
1392                             const void* cSrc, size_t cSrcSize,
1393                             const FSE_DTable* dt)
1394 {
1395     FSE_DTableHeader DTableH;
1396     U32 fastMode;
1397 
1398     memcpy(&DTableH, dt, sizeof(DTableH));
1399     fastMode = DTableH.fastMode;
1400 
1401     /* select fast mode (static) */
1402     if (fastMode) return FSE_decompress_usingDTable_generic(dst, originalSize, cSrc, cSrcSize, dt, 1);
1403     return FSE_decompress_usingDTable_generic(dst, originalSize, cSrc, cSrcSize, dt, 0);
1404 }
1405 
1406 
1407 static size_t FSE_decompress(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize)
1408 {
1409     const BYTE* const istart = (const BYTE*)cSrc;
1410     const BYTE* ip = istart;
1411     short counting[FSE_MAX_SYMBOL_VALUE+1];
1412     DTable_max_t dt;   /* Static analyzer seems unable to understand this table will be properly initialized later */
1413     unsigned tableLog;
1414     unsigned maxSymbolValue = FSE_MAX_SYMBOL_VALUE;
1415     size_t errorCode;
1416 
1417     if (cSrcSize<2) return ERROR(srcSize_wrong);   /* too small input size */
1418 
1419     /* normal FSE decoding mode */
1420     errorCode = FSE_readNCount (counting, &maxSymbolValue, &tableLog, istart, cSrcSize);
1421     if (FSE_isError(errorCode)) return errorCode;
1422     if (errorCode >= cSrcSize) return ERROR(srcSize_wrong);   /* too small input size */
1423     ip += errorCode;
1424     cSrcSize -= errorCode;
1425 
1426     errorCode = FSE_buildDTable (dt, counting, maxSymbolValue, tableLog);
1427     if (FSE_isError(errorCode)) return errorCode;
1428 
1429     /* always return, even if it is an error code */
1430     return FSE_decompress_usingDTable (dst, maxDstSize, ip, cSrcSize, dt);
1431 }
1432 
1433 
1434 
1435 #endif   /* FSE_COMMONDEFS_ONLY */
1436 
1437 
1438 /* ******************************************************************
1439    Huff0 : Huffman coder, part of New Generation Entropy library
1440    header file
1441    Copyright (C) 2013-2015, Yann Collet.
1442 
1443    BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
1444 
1445    Redistribution and use in source and binary forms, with or without
1446    modification, are permitted provided that the following conditions are
1447    met:
1448 
1449        * Redistributions of source code must retain the above copyright
1450    notice, this list of conditions and the following disclaimer.
1451        * Redistributions in binary form must reproduce the above
1452    copyright notice, this list of conditions and the following disclaimer
1453    in the documentation and/or other materials provided with the
1454    distribution.
1455 
1456    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
1457    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
1458    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
1459    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
1460    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
1461    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
1462    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
1463    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
1464    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
1465    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
1466    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1467 
1468    You can contact the author at :
1469    - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
1470    - Public forum : https://groups.google.com/forum/#!forum/lz4c
1471 ****************************************************************** */
1472 #ifndef HUFF0_H
1473 #define HUFF0_H
1474 
1475 #if defined (__cplusplus)
1476 extern "C" {
1477 #endif
1478 
1479 
1480 /* ****************************************
1481 *  Dependency
1482 ******************************************/
1483 #include <stddef.h>    /* size_t */
1484 
1485 
1486 /* ****************************************
1487 *  Huff0 simple functions
1488 ******************************************/
1489 static size_t HUF_decompress(void* dst,  size_t dstSize,
1490                 const void* cSrc, size_t cSrcSize);
1491 /*!
1492 HUF_decompress():
1493     Decompress Huff0 data from buffer 'cSrc', of size 'cSrcSize',
1494     into already allocated destination buffer 'dst', of size 'dstSize'.
1495     'dstSize' must be the exact size of original (uncompressed) data.
1496     Note : in contrast with FSE, HUF_decompress can regenerate RLE (cSrcSize==1) and uncompressed (cSrcSize==dstSize) data, because it knows size to regenerate.
1497     @return : size of regenerated data (== dstSize)
1498               or an error code, which can be tested using HUF_isError()
1499 */
1500 
1501 
1502 /* ****************************************
1503 *  Tool functions
1504 ******************************************/
1505 /* Error Management */
1506 static unsigned    HUF_isError(size_t code);        /* tells if a return value is an error code */
1507 
1508 
1509 #if defined (__cplusplus)
1510 }
1511 #endif
1512 
1513 #endif   /* HUFF0_H */
1514 
1515 
1516 /* ******************************************************************
1517    Huff0 : Huffman coder, part of New Generation Entropy library
1518    header file for static linking (only)
1519    Copyright (C) 2013-2015, Yann Collet
1520 
1521    BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
1522 
1523    Redistribution and use in source and binary forms, with or without
1524    modification, are permitted provided that the following conditions are
1525    met:
1526 
1527        * Redistributions of source code must retain the above copyright
1528    notice, this list of conditions and the following disclaimer.
1529        * Redistributions in binary form must reproduce the above
1530    copyright notice, this list of conditions and the following disclaimer
1531    in the documentation and/or other materials provided with the
1532    distribution.
1533 
1534    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
1535    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
1536    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
1537    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
1538    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
1539    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
1540    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
1541    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
1542    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
1543    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
1544    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1545 
1546    You can contact the author at :
1547    - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
1548    - Public forum : https://groups.google.com/forum/#!forum/lz4c
1549 ****************************************************************** */
1550 #ifndef HUFF0_STATIC_H
1551 #define HUFF0_STATIC_H
1552 
1553 #if defined (__cplusplus)
1554 extern "C" {
1555 #endif
1556 
1557 
1558 
1559 /* ****************************************
1560 *  Static allocation macros
1561 ******************************************/
1562 /* static allocation of Huff0's DTable */
1563 #define HUF_DTABLE_SIZE(maxTableLog)   (1 + (1<<maxTableLog))  /* nb Cells; use unsigned short for X2, unsigned int for X4 */
1564 #define HUF_CREATE_STATIC_DTABLEX2(DTable, maxTableLog) \
1565         unsigned short DTable[HUF_DTABLE_SIZE(maxTableLog)] = { maxTableLog }
1566 #define HUF_CREATE_STATIC_DTABLEX4(DTable, maxTableLog) \
1567         unsigned int DTable[HUF_DTABLE_SIZE(maxTableLog)] = { maxTableLog }
1568 #define HUF_CREATE_STATIC_DTABLEX6(DTable, maxTableLog) \
1569         unsigned int DTable[HUF_DTABLE_SIZE(maxTableLog) * 3 / 2] = { maxTableLog }
1570 
1571 
1572 /* ****************************************
1573 *  Advanced decompression functions
1574 ******************************************/
1575 static size_t HUF_decompress4X2 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize);   /* single-symbol decoder */
1576 static size_t HUF_decompress4X4 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize);   /* double-symbols decoder */
1577 
1578 
1579 /* ****************************************
1580 *  Huff0 detailed API
1581 ******************************************/
1582 /*!
1583 HUF_decompress() does the following:
1584 1. select the decompression algorithm (X2, X4, X6) based on pre-computed heuristics
1585 2. build Huffman table from save, using HUF_readDTableXn()
1586 3. decode 1 or 4 segments in parallel using HUF_decompressSXn_usingDTable
1587 
1588 */
1589 static size_t HUF_readDTableX2 (unsigned short* DTable, const void* src, size_t srcSize);
1590 static size_t HUF_readDTableX4 (unsigned* DTable, const void* src, size_t srcSize);
1591 
1592 static size_t HUF_decompress4X2_usingDTable(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const unsigned short* DTable);
1593 static size_t HUF_decompress4X4_usingDTable(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const unsigned* DTable);
1594 
1595 
1596 #if defined (__cplusplus)
1597 }
1598 #endif
1599 
1600 #endif /* HUFF0_STATIC_H */
1601 
1602 
1603 
1604 /* ******************************************************************
1605    Huff0 : Huffman coder, part of New Generation Entropy library
1606    Copyright (C) 2013-2015, Yann Collet.
1607 
1608    BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
1609 
1610    Redistribution and use in source and binary forms, with or without
1611    modification, are permitted provided that the following conditions are
1612    met:
1613 
1614        * Redistributions of source code must retain the above copyright
1615    notice, this list of conditions and the following disclaimer.
1616        * Redistributions in binary form must reproduce the above
1617    copyright notice, this list of conditions and the following disclaimer
1618    in the documentation and/or other materials provided with the
1619    distribution.
1620 
1621    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
1622    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
1623    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
1624    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
1625    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
1626    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
1627    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
1628    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
1629    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
1630    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
1631    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1632 
1633     You can contact the author at :
1634     - FSE+Huff0 source repository : https://github.com/Cyan4973/FiniteStateEntropy
1635 ****************************************************************** */
1636 
1637 /* **************************************************************
1638 *  Compiler specifics
1639 ****************************************************************/
1640 #if defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
1641 /* inline is defined */
1642 #elif defined(_MSC_VER)
1643 #  define inline __inline
1644 #else
1645 #  define inline /* disable inline */
1646 #endif
1647 
1648 
1649 #ifdef _MSC_VER    /* Visual Studio */
1650 #  pragma warning(disable : 4127)        /* disable: C4127: conditional expression is constant */
1651 #endif
1652 
1653 
1654 /* **************************************************************
1655 *  Includes
1656 ****************************************************************/
1657 #include <stdlib.h>     /* malloc, free, qsort */
1658 #include <string.h>     /* memcpy, memset */
1659 #include <stdio.h>      /* printf (debug) */
1660 
1661 
1662 /* **************************************************************
1663 *  Constants
1664 ****************************************************************/
1665 #define HUF_ABSOLUTEMAX_TABLELOG  16   /* absolute limit of HUF_MAX_TABLELOG. Beyond that value, code does not work */
1666 #define HUF_MAX_TABLELOG  12           /* max configured tableLog (for static allocation); can be modified up to HUF_ABSOLUTEMAX_TABLELOG */
1667 #define HUF_DEFAULT_TABLELOG  HUF_MAX_TABLELOG   /* tableLog by default, when not specified */
1668 #define HUF_MAX_SYMBOL_VALUE 255
1669 #if (HUF_MAX_TABLELOG > HUF_ABSOLUTEMAX_TABLELOG)
1670 #  error "HUF_MAX_TABLELOG is too large !"
1671 #endif
1672 
1673 
1674 /* **************************************************************
1675 *  Error Management
1676 ****************************************************************/
1677 static unsigned HUF_isError(size_t code) { return ERR_isError(code); }
1678 #define HUF_STATIC_ASSERT(c) { enum { HUF_static_assert = 1/(int)(!!(c)) }; }   /* use only *after* variable declarations */
1679 
1680 
1681 
1682 /*-*******************************************************
1683 *  Huff0 : Huffman block decompression
1684 *********************************************************/
1685 typedef struct { BYTE byte; BYTE nbBits; } HUF_DEltX2;   /* single-symbol decoding */
1686 
1687 typedef struct { U16 sequence; BYTE nbBits; BYTE length; } HUF_DEltX4;  /* double-symbols decoding */
1688 
1689 typedef struct { BYTE symbol; BYTE weight; } sortedSymbol_t;
1690 
1691 /*! HUF_readStats
1692     Read compact Huffman tree, saved by HUF_writeCTable
1693     @huffWeight : destination buffer
1694     @return : size read from `src`
1695 */
1696 static size_t HUF_readStats(BYTE* huffWeight, size_t hwSize, U32* rankStats,
1697                             U32* nbSymbolsPtr, U32* tableLogPtr,
1698                             const void* src, size_t srcSize)
1699 {
1700     U32 weightTotal;
1701     U32 tableLog;
1702     const BYTE* ip = (const BYTE*) src;
1703     size_t iSize;
1704     size_t oSize;
1705     U32 n;
1706 
1707     if (!srcSize) return ERROR(srcSize_wrong);
1708     iSize = ip[0];
1709     //memset(huffWeight, 0, hwSize);   /* is not necessary, even though some analyzer complain ... */
1710 
1711     if (iSize >= 128)  /* special header */
1712     {
1713         if (iSize >= (242))   /* RLE */
1714         {
1715             static int l[14] = { 1, 2, 3, 4, 7, 8, 15, 16, 31, 32, 63, 64, 127, 128 };
1716             oSize = l[iSize-242];
1717             memset(huffWeight, 1, hwSize);
1718             iSize = 0;
1719         }
1720         else   /* Incompressible */
1721         {
1722             oSize = iSize - 127;
1723             iSize = ((oSize+1)/2);
1724             if (iSize+1 > srcSize) return ERROR(srcSize_wrong);
1725             if (oSize >= hwSize) return ERROR(corruption_detected);
1726             ip += 1;
1727             for (n=0; n<oSize; n+=2)
1728             {
1729                 huffWeight[n]   = ip[n/2] >> 4;
1730                 huffWeight[n+1] = ip[n/2] & 15;
1731             }
1732         }
1733     }
1734     else  /* header compressed with FSE (normal case) */
1735     {
1736         if (iSize+1 > srcSize) return ERROR(srcSize_wrong);
1737         oSize = FSE_decompress(huffWeight, hwSize-1, ip+1, iSize);   /* max (hwSize-1) values decoded, as last one is implied */
1738         if (FSE_isError(oSize)) return oSize;
1739     }
1740 
1741     /* collect weight stats */
1742     memset(rankStats, 0, (HUF_ABSOLUTEMAX_TABLELOG + 1) * sizeof(U32));
1743     weightTotal = 0;
1744     for (n=0; n<oSize; n++)
1745     {
1746         if (huffWeight[n] >= HUF_ABSOLUTEMAX_TABLELOG) return ERROR(corruption_detected);
1747         rankStats[huffWeight[n]]++;
1748         weightTotal += (1 << huffWeight[n]) >> 1;
1749     }
1750     if (weightTotal == 0) return ERROR(corruption_detected);
1751 
1752     /* get last non-null symbol weight (implied, total must be 2^n) */
1753     tableLog = BIT_highbit32(weightTotal) + 1;
1754     if (tableLog > HUF_ABSOLUTEMAX_TABLELOG) return ERROR(corruption_detected);
1755     {
1756         U32 total = 1 << tableLog;
1757         U32 rest = total - weightTotal;
1758         U32 verif = 1 << BIT_highbit32(rest);
1759         U32 lastWeight = BIT_highbit32(rest) + 1;
1760         if (verif != rest) return ERROR(corruption_detected);    /* last value must be a clean power of 2 */
1761         huffWeight[oSize] = (BYTE)lastWeight;
1762         rankStats[lastWeight]++;
1763     }
1764 
1765     /* check tree construction validity */
1766     if ((rankStats[1] < 2) || (rankStats[1] & 1)) return ERROR(corruption_detected);   /* by construction : at least 2 elts of rank 1, must be even */
1767 
1768     /* results */
1769     *nbSymbolsPtr = (U32)(oSize+1);
1770     *tableLogPtr = tableLog;
1771     return iSize+1;
1772 }
1773 
1774 
1775 /**************************/
1776 /* single-symbol decoding */
1777 /**************************/
1778 
1779 static size_t HUF_readDTableX2 (U16* DTable, const void* src, size_t srcSize)
1780 {
1781     BYTE huffWeight[HUF_MAX_SYMBOL_VALUE + 1];
1782     U32 rankVal[HUF_ABSOLUTEMAX_TABLELOG + 1];   /* large enough for values from 0 to 16 */
1783     U32 tableLog = 0;
1784     size_t iSize;
1785     U32 nbSymbols = 0;
1786     U32 n;
1787     U32 nextRankStart;
1788     void* const dtPtr = DTable + 1;
1789     HUF_DEltX2* const dt = (HUF_DEltX2*)dtPtr;
1790 
1791     HUF_STATIC_ASSERT(sizeof(HUF_DEltX2) == sizeof(U16));   /* if compilation fails here, assertion is false */
1792     //memset(huffWeight, 0, sizeof(huffWeight));   /* is not necessary, even though some analyzer complain ... */
1793 
1794     iSize = HUF_readStats(huffWeight, HUF_MAX_SYMBOL_VALUE + 1, rankVal, &nbSymbols, &tableLog, src, srcSize);
1795     if (HUF_isError(iSize)) return iSize;
1796 
1797     /* check result */
1798     if (tableLog > DTable[0]) return ERROR(tableLog_tooLarge);   /* DTable is too small */
1799     DTable[0] = (U16)tableLog;   /* maybe should separate sizeof DTable, as allocated, from used size of DTable, in case of DTable re-use */
1800 
1801     /* Prepare ranks */
1802     nextRankStart = 0;
1803     for (n=1; n<=tableLog; n++)
1804     {
1805         U32 current = nextRankStart;
1806         nextRankStart += (rankVal[n] << (n-1));
1807         rankVal[n] = current;
1808     }
1809 
1810     /* fill DTable */
1811     for (n=0; n<nbSymbols; n++)
1812     {
1813         const U32 w = huffWeight[n];
1814         const U32 length = (1 << w) >> 1;
1815         U32 i;
1816         HUF_DEltX2 D;
1817         D.byte = (BYTE)n; D.nbBits = (BYTE)(tableLog + 1 - w);
1818         for (i = rankVal[w]; i < rankVal[w] + length; i++)
1819             dt[i] = D;
1820         rankVal[w] += length;
1821     }
1822 
1823     return iSize;
1824 }
1825 
1826 static BYTE HUF_decodeSymbolX2(BIT_DStream_t* Dstream, const HUF_DEltX2* dt, const U32 dtLog)
1827 {
1828         const size_t val = BIT_lookBitsFast(Dstream, dtLog); /* note : dtLog >= 1 */
1829         const BYTE c = dt[val].byte;
1830         BIT_skipBits(Dstream, dt[val].nbBits);
1831         return c;
1832 }
1833 
1834 #define HUF_DECODE_SYMBOLX2_0(ptr, DStreamPtr) \
1835     *ptr++ = HUF_decodeSymbolX2(DStreamPtr, dt, dtLog)
1836 
1837 #define HUF_DECODE_SYMBOLX2_1(ptr, DStreamPtr) \
1838     if (MEM_64bits() || (HUF_MAX_TABLELOG<=12)) \
1839         HUF_DECODE_SYMBOLX2_0(ptr, DStreamPtr)
1840 
1841 #define HUF_DECODE_SYMBOLX2_2(ptr, DStreamPtr) \
1842     if (MEM_64bits()) \
1843         HUF_DECODE_SYMBOLX2_0(ptr, DStreamPtr)
1844 
1845 static inline size_t HUF_decodeStreamX2(BYTE* p, BIT_DStream_t* const bitDPtr, BYTE* const pEnd, const HUF_DEltX2* const dt, const U32 dtLog)
1846 {
1847     BYTE* const pStart = p;
1848 
1849     /* up to 4 symbols at a time */
1850     while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) && (p <= pEnd-4))
1851     {
1852         HUF_DECODE_SYMBOLX2_2(p, bitDPtr);
1853         HUF_DECODE_SYMBOLX2_1(p, bitDPtr);
1854         HUF_DECODE_SYMBOLX2_2(p, bitDPtr);
1855         HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
1856     }
1857 
1858     /* closer to the end */
1859     while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) && (p < pEnd))
1860         HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
1861 
1862     /* no more data to retrieve from bitstream, hence no need to reload */
1863     while (p < pEnd)
1864         HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
1865 
1866     return pEnd-pStart;
1867 }
1868 
1869 
1870 static size_t HUF_decompress4X2_usingDTable(
1871           void* dst,  size_t dstSize,
1872     const void* cSrc, size_t cSrcSize,
1873     const U16* DTable)
1874 {
1875     if (cSrcSize < 10) return ERROR(corruption_detected);   /* strict minimum : jump table + 1 byte per stream */
1876 
1877     {
1878         const BYTE* const istart = (const BYTE*) cSrc;
1879         BYTE* const ostart = (BYTE*) dst;
1880         BYTE* const oend = ostart + dstSize;
1881         const void* const dtPtr = DTable;
1882         const HUF_DEltX2* const dt = ((const HUF_DEltX2*)dtPtr) +1;
1883         const U32 dtLog = DTable[0];
1884         size_t errorCode;
1885 
1886         /* Init */
1887         BIT_DStream_t bitD1;
1888         BIT_DStream_t bitD2;
1889         BIT_DStream_t bitD3;
1890         BIT_DStream_t bitD4;
1891         const size_t length1 = MEM_readLE16(istart);
1892         const size_t length2 = MEM_readLE16(istart+2);
1893         const size_t length3 = MEM_readLE16(istart+4);
1894         size_t length4;
1895         const BYTE* const istart1 = istart + 6;  /* jumpTable */
1896         const BYTE* const istart2 = istart1 + length1;
1897         const BYTE* const istart3 = istart2 + length2;
1898         const BYTE* const istart4 = istart3 + length3;
1899         const size_t segmentSize = (dstSize+3) / 4;
1900         BYTE* const opStart2 = ostart + segmentSize;
1901         BYTE* const opStart3 = opStart2 + segmentSize;
1902         BYTE* const opStart4 = opStart3 + segmentSize;
1903         BYTE* op1 = ostart;
1904         BYTE* op2 = opStart2;
1905         BYTE* op3 = opStart3;
1906         BYTE* op4 = opStart4;
1907         U32 endSignal;
1908 
1909         length4 = cSrcSize - (length1 + length2 + length3 + 6);
1910         if (length4 > cSrcSize) return ERROR(corruption_detected);   /* overflow */
1911         errorCode = BIT_initDStream(&bitD1, istart1, length1);
1912         if (HUF_isError(errorCode)) return errorCode;
1913         errorCode = BIT_initDStream(&bitD2, istart2, length2);
1914         if (HUF_isError(errorCode)) return errorCode;
1915         errorCode = BIT_initDStream(&bitD3, istart3, length3);
1916         if (HUF_isError(errorCode)) return errorCode;
1917         errorCode = BIT_initDStream(&bitD4, istart4, length4);
1918         if (HUF_isError(errorCode)) return errorCode;
1919 
1920         /* 16-32 symbols per loop (4-8 symbols per stream) */
1921         endSignal = BIT_reloadDStream(&bitD1) | BIT_reloadDStream(&bitD2) | BIT_reloadDStream(&bitD3) | BIT_reloadDStream(&bitD4);
1922         for ( ; (endSignal==BIT_DStream_unfinished) && (op4<(oend-7)) ; )
1923         {
1924             HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
1925             HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
1926             HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
1927             HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
1928             HUF_DECODE_SYMBOLX2_1(op1, &bitD1);
1929             HUF_DECODE_SYMBOLX2_1(op2, &bitD2);
1930             HUF_DECODE_SYMBOLX2_1(op3, &bitD3);
1931             HUF_DECODE_SYMBOLX2_1(op4, &bitD4);
1932             HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
1933             HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
1934             HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
1935             HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
1936             HUF_DECODE_SYMBOLX2_0(op1, &bitD1);
1937             HUF_DECODE_SYMBOLX2_0(op2, &bitD2);
1938             HUF_DECODE_SYMBOLX2_0(op3, &bitD3);
1939             HUF_DECODE_SYMBOLX2_0(op4, &bitD4);
1940 
1941             endSignal = BIT_reloadDStream(&bitD1) | BIT_reloadDStream(&bitD2) | BIT_reloadDStream(&bitD3) | BIT_reloadDStream(&bitD4);
1942         }
1943 
1944         /* check corruption */
1945         if (op1 > opStart2) return ERROR(corruption_detected);
1946         if (op2 > opStart3) return ERROR(corruption_detected);
1947         if (op3 > opStart4) return ERROR(corruption_detected);
1948         /* note : op4 supposed already verified within main loop */
1949 
1950         /* finish bitStreams one by one */
1951         HUF_decodeStreamX2(op1, &bitD1, opStart2, dt, dtLog);
1952         HUF_decodeStreamX2(op2, &bitD2, opStart3, dt, dtLog);
1953         HUF_decodeStreamX2(op3, &bitD3, opStart4, dt, dtLog);
1954         HUF_decodeStreamX2(op4, &bitD4, oend,     dt, dtLog);
1955 
1956         /* check */
1957         endSignal = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
1958         if (!endSignal) return ERROR(corruption_detected);
1959 
1960         /* decoded size */
1961         return dstSize;
1962     }
1963 }
1964 
1965 
1966 static size_t HUF_decompress4X2 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
1967 {
1968     HUF_CREATE_STATIC_DTABLEX2(DTable, HUF_MAX_TABLELOG);
1969     const BYTE* ip = (const BYTE*) cSrc;
1970     size_t errorCode;
1971 
1972     errorCode = HUF_readDTableX2 (DTable, cSrc, cSrcSize);
1973     if (HUF_isError(errorCode)) return errorCode;
1974     if (errorCode >= cSrcSize) return ERROR(srcSize_wrong);
1975     ip += errorCode;
1976     cSrcSize -= errorCode;
1977 
1978     return HUF_decompress4X2_usingDTable (dst, dstSize, ip, cSrcSize, DTable);
1979 }
1980 
1981 
1982 /***************************/
1983 /* double-symbols decoding */
1984 /***************************/
1985 
1986 static void HUF_fillDTableX4Level2(HUF_DEltX4* DTable, U32 sizeLog, const U32 consumed,
1987                            const U32* rankValOrigin, const int minWeight,
1988                            const sortedSymbol_t* sortedSymbols, const U32 sortedListSize,
1989                            U32 nbBitsBaseline, U16 baseSeq)
1990 {
1991     HUF_DEltX4 DElt;
1992     U32 rankVal[HUF_ABSOLUTEMAX_TABLELOG + 1];
1993     U32 s;
1994 
1995     /* get pre-calculated rankVal */
1996     memcpy(rankVal, rankValOrigin, sizeof(rankVal));
1997 
1998     /* fill skipped values */
1999     if (minWeight>1)
2000     {
2001         U32 i, skipSize = rankVal[minWeight];
2002         MEM_writeLE16(&(DElt.sequence), baseSeq);
2003         DElt.nbBits   = (BYTE)(consumed);
2004         DElt.length   = 1;
2005         for (i = 0; i < skipSize; i++)
2006             DTable[i] = DElt;
2007     }
2008 
2009     /* fill DTable */
2010     for (s=0; s<sortedListSize; s++)   /* note : sortedSymbols already skipped */
2011     {
2012         const U32 symbol = sortedSymbols[s].symbol;
2013         const U32 weight = sortedSymbols[s].weight;
2014         const U32 nbBits = nbBitsBaseline - weight;
2015         const U32 length = 1 << (sizeLog-nbBits);
2016         const U32 start = rankVal[weight];
2017         U32 i = start;
2018         const U32 end = start + length;
2019 
2020         MEM_writeLE16(&(DElt.sequence), (U16)(baseSeq + (symbol << 8)));
2021         DElt.nbBits = (BYTE)(nbBits + consumed);
2022         DElt.length = 2;
2023         do { DTable[i++] = DElt; } while (i<end);   /* since length >= 1 */
2024 
2025         rankVal[weight] += length;
2026     }
2027 }
2028 
2029 typedef U32 rankVal_t[HUF_ABSOLUTEMAX_TABLELOG][HUF_ABSOLUTEMAX_TABLELOG + 1];
2030 
2031 static void HUF_fillDTableX4(HUF_DEltX4* DTable, const U32 targetLog,
2032                            const sortedSymbol_t* sortedList, const U32 sortedListSize,
2033                            const U32* rankStart, rankVal_t rankValOrigin, const U32 maxWeight,
2034                            const U32 nbBitsBaseline)
2035 {
2036     U32 rankVal[HUF_ABSOLUTEMAX_TABLELOG + 1];
2037     const int scaleLog = nbBitsBaseline - targetLog;   /* note : targetLog >= srcLog, hence scaleLog <= 1 */
2038     const U32 minBits  = nbBitsBaseline - maxWeight;
2039     U32 s;
2040 
2041     memcpy(rankVal, rankValOrigin, sizeof(rankVal));
2042 
2043     /* fill DTable */
2044     for (s=0; s<sortedListSize; s++)
2045     {
2046         const U16 symbol = sortedList[s].symbol;
2047         const U32 weight = sortedList[s].weight;
2048         const U32 nbBits = nbBitsBaseline - weight;
2049         const U32 start = rankVal[weight];
2050         const U32 length = 1 << (targetLog-nbBits);
2051 
2052         if (targetLog-nbBits >= minBits)   /* enough room for a second symbol */
2053         {
2054             U32 sortedRank;
2055             int minWeight = nbBits + scaleLog;
2056             if (minWeight < 1) minWeight = 1;
2057             sortedRank = rankStart[minWeight];
2058             HUF_fillDTableX4Level2(DTable+start, targetLog-nbBits, nbBits,
2059                            rankValOrigin[nbBits], minWeight,
2060                            sortedList+sortedRank, sortedListSize-sortedRank,
2061                            nbBitsBaseline, symbol);
2062         }
2063         else
2064         {
2065             U32 i;
2066             const U32 end = start + length;
2067             HUF_DEltX4 DElt;
2068 
2069             MEM_writeLE16(&(DElt.sequence), symbol);
2070             DElt.nbBits   = (BYTE)(nbBits);
2071             DElt.length   = 1;
2072             for (i = start; i < end; i++)
2073                 DTable[i] = DElt;
2074         }
2075         rankVal[weight] += length;
2076     }
2077 }
2078 
2079 static size_t HUF_readDTableX4 (U32* DTable, const void* src, size_t srcSize)
2080 {
2081     BYTE weightList[HUF_MAX_SYMBOL_VALUE + 1];
2082     sortedSymbol_t sortedSymbol[HUF_MAX_SYMBOL_VALUE + 1];
2083     U32 rankStats[HUF_ABSOLUTEMAX_TABLELOG + 1] = { 0 };
2084     U32 rankStart0[HUF_ABSOLUTEMAX_TABLELOG + 2] = { 0 };
2085     U32* const rankStart = rankStart0+1;
2086     rankVal_t rankVal;
2087     U32 tableLog, maxW, sizeOfSort, nbSymbols;
2088     const U32 memLog = DTable[0];
2089     size_t iSize;
2090     void* dtPtr = DTable;
2091     HUF_DEltX4* const dt = ((HUF_DEltX4*)dtPtr) + 1;
2092 
2093     HUF_STATIC_ASSERT(sizeof(HUF_DEltX4) == sizeof(U32));   /* if compilation fails here, assertion is false */
2094     if (memLog > HUF_ABSOLUTEMAX_TABLELOG) return ERROR(tableLog_tooLarge);
2095     //memset(weightList, 0, sizeof(weightList));   /* is not necessary, even though some analyzer complain ... */
2096 
2097     iSize = HUF_readStats(weightList, HUF_MAX_SYMBOL_VALUE + 1, rankStats, &nbSymbols, &tableLog, src, srcSize);
2098     if (HUF_isError(iSize)) return iSize;
2099 
2100     /* check result */
2101     if (tableLog > memLog) return ERROR(tableLog_tooLarge);   /* DTable can't fit code depth */
2102 
2103     /* find maxWeight */
2104     for (maxW = tableLog; rankStats[maxW]==0; maxW--)
2105         { if (!maxW) return ERROR(GENERIC); }  /* necessarily finds a solution before maxW==0 */
2106 
2107     /* Get start index of each weight */
2108     {
2109         U32 w, nextRankStart = 0;
2110         for (w=1; w<=maxW; w++)
2111         {
2112             U32 current = nextRankStart;
2113             nextRankStart += rankStats[w];
2114             rankStart[w] = current;
2115         }
2116         rankStart[0] = nextRankStart;   /* put all 0w symbols at the end of sorted list*/
2117         sizeOfSort = nextRankStart;
2118     }
2119 
2120     /* sort symbols by weight */
2121     {
2122         U32 s;
2123         for (s=0; s<nbSymbols; s++)
2124         {
2125             U32 w = weightList[s];
2126             U32 r = rankStart[w]++;
2127             sortedSymbol[r].symbol = (BYTE)s;
2128             sortedSymbol[r].weight = (BYTE)w;
2129         }
2130         rankStart[0] = 0;   /* forget 0w symbols; this is beginning of weight(1) */
2131     }
2132 
2133     /* Build rankVal */
2134     {
2135         const U32 minBits = tableLog+1 - maxW;
2136         U32 nextRankVal = 0;
2137         U32 w, consumed;
2138         const int rescale = (memLog-tableLog) - 1;   /* tableLog <= memLog */
2139         U32* rankVal0 = rankVal[0];
2140         for (w=1; w<=maxW; w++)
2141         {
2142             U32 current = nextRankVal;
2143             nextRankVal += rankStats[w] << (w+rescale);
2144             rankVal0[w] = current;
2145         }
2146         for (consumed = minBits; consumed <= memLog - minBits; consumed++)
2147         {
2148             U32* rankValPtr = rankVal[consumed];
2149             for (w = 1; w <= maxW; w++)
2150             {
2151                 rankValPtr[w] = rankVal0[w] >> consumed;
2152             }
2153         }
2154     }
2155 
2156     HUF_fillDTableX4(dt, memLog,
2157                    sortedSymbol, sizeOfSort,
2158                    rankStart0, rankVal, maxW,
2159                    tableLog+1);
2160 
2161     return iSize;
2162 }
2163 
2164 
2165 static U32 HUF_decodeSymbolX4(void* op, BIT_DStream_t* DStream, const HUF_DEltX4* dt, const U32 dtLog)
2166 {
2167     const size_t val = BIT_lookBitsFast(DStream, dtLog);   /* note : dtLog >= 1 */
2168     memcpy(op, dt+val, 2);
2169     BIT_skipBits(DStream, dt[val].nbBits);
2170     return dt[val].length;
2171 }
2172 
2173 static U32 HUF_decodeLastSymbolX4(void* op, BIT_DStream_t* DStream, const HUF_DEltX4* dt, const U32 dtLog)
2174 {
2175     const size_t val = BIT_lookBitsFast(DStream, dtLog);   /* note : dtLog >= 1 */
2176     memcpy(op, dt+val, 1);
2177     if (dt[val].length==1) BIT_skipBits(DStream, dt[val].nbBits);
2178     else
2179     {
2180         if (DStream->bitsConsumed < (sizeof(DStream->bitContainer)*8))
2181         {
2182             BIT_skipBits(DStream, dt[val].nbBits);
2183             if (DStream->bitsConsumed > (sizeof(DStream->bitContainer)*8))
2184                 DStream->bitsConsumed = (sizeof(DStream->bitContainer)*8);   /* ugly hack; works only because it's the last symbol. Note : can't easily extract nbBits from just this symbol */
2185         }
2186     }
2187     return 1;
2188 }
2189 
2190 
2191 #define HUF_DECODE_SYMBOLX4_0(ptr, DStreamPtr) \
2192     ptr += HUF_decodeSymbolX4(ptr, DStreamPtr, dt, dtLog)
2193 
2194 #define HUF_DECODE_SYMBOLX4_1(ptr, DStreamPtr) \
2195     if (MEM_64bits() || (HUF_MAX_TABLELOG<=12)) \
2196         ptr += HUF_decodeSymbolX4(ptr, DStreamPtr, dt, dtLog)
2197 
2198 #define HUF_DECODE_SYMBOLX4_2(ptr, DStreamPtr) \
2199     if (MEM_64bits()) \
2200         ptr += HUF_decodeSymbolX4(ptr, DStreamPtr, dt, dtLog)
2201 
2202 static inline size_t HUF_decodeStreamX4(BYTE* p, BIT_DStream_t* bitDPtr, BYTE* const pEnd, const HUF_DEltX4* const dt, const U32 dtLog)
2203 {
2204     BYTE* const pStart = p;
2205 
2206     /* up to 8 symbols at a time */
2207     while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) && (p < pEnd-7))
2208     {
2209         HUF_DECODE_SYMBOLX4_2(p, bitDPtr);
2210         HUF_DECODE_SYMBOLX4_1(p, bitDPtr);
2211         HUF_DECODE_SYMBOLX4_2(p, bitDPtr);
2212         HUF_DECODE_SYMBOLX4_0(p, bitDPtr);
2213     }
2214 
2215     /* closer to the end */
2216     while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) && (p <= pEnd-2))
2217         HUF_DECODE_SYMBOLX4_0(p, bitDPtr);
2218 
2219     while (p <= pEnd-2)
2220         HUF_DECODE_SYMBOLX4_0(p, bitDPtr);   /* no need to reload : reached the end of DStream */
2221 
2222     if (p < pEnd)
2223         p += HUF_decodeLastSymbolX4(p, bitDPtr, dt, dtLog);
2224 
2225     return p-pStart;
2226 }
2227 
2228 static size_t HUF_decompress4X4_usingDTable(
2229           void* dst,  size_t dstSize,
2230     const void* cSrc, size_t cSrcSize,
2231     const U32* DTable)
2232 {
2233     if (cSrcSize < 10) return ERROR(corruption_detected);   /* strict minimum : jump table + 1 byte per stream */
2234 
2235     {
2236         const BYTE* const istart = (const BYTE*) cSrc;
2237         BYTE* const ostart = (BYTE*) dst;
2238         BYTE* const oend = ostart + dstSize;
2239         const void* const dtPtr = DTable;
2240         const HUF_DEltX4* const dt = ((const HUF_DEltX4*)dtPtr) +1;
2241         const U32 dtLog = DTable[0];
2242         size_t errorCode;
2243 
2244         /* Init */
2245         BIT_DStream_t bitD1;
2246         BIT_DStream_t bitD2;
2247         BIT_DStream_t bitD3;
2248         BIT_DStream_t bitD4;
2249         const size_t length1 = MEM_readLE16(istart);
2250         const size_t length2 = MEM_readLE16(istart+2);
2251         const size_t length3 = MEM_readLE16(istart+4);
2252         size_t length4;
2253         const BYTE* const istart1 = istart + 6;  /* jumpTable */
2254         const BYTE* const istart2 = istart1 + length1;
2255         const BYTE* const istart3 = istart2 + length2;
2256         const BYTE* const istart4 = istart3 + length3;
2257         const size_t segmentSize = (dstSize+3) / 4;
2258         BYTE* const opStart2 = ostart + segmentSize;
2259         BYTE* const opStart3 = opStart2 + segmentSize;
2260         BYTE* const opStart4 = opStart3 + segmentSize;
2261         BYTE* op1 = ostart;
2262         BYTE* op2 = opStart2;
2263         BYTE* op3 = opStart3;
2264         BYTE* op4 = opStart4;
2265         U32 endSignal;
2266 
2267         length4 = cSrcSize - (length1 + length2 + length3 + 6);
2268         if (length4 > cSrcSize) return ERROR(corruption_detected);   /* overflow */
2269         errorCode = BIT_initDStream(&bitD1, istart1, length1);
2270         if (HUF_isError(errorCode)) return errorCode;
2271         errorCode = BIT_initDStream(&bitD2, istart2, length2);
2272         if (HUF_isError(errorCode)) return errorCode;
2273         errorCode = BIT_initDStream(&bitD3, istart3, length3);
2274         if (HUF_isError(errorCode)) return errorCode;
2275         errorCode = BIT_initDStream(&bitD4, istart4, length4);
2276         if (HUF_isError(errorCode)) return errorCode;
2277 
2278         /* 16-32 symbols per loop (4-8 symbols per stream) */
2279         endSignal = BIT_reloadDStream(&bitD1) | BIT_reloadDStream(&bitD2) | BIT_reloadDStream(&bitD3) | BIT_reloadDStream(&bitD4);
2280         for ( ; (endSignal==BIT_DStream_unfinished) && (op4<(oend-7)) ; )
2281         {
2282             HUF_DECODE_SYMBOLX4_2(op1, &bitD1);
2283             HUF_DECODE_SYMBOLX4_2(op2, &bitD2);
2284             HUF_DECODE_SYMBOLX4_2(op3, &bitD3);
2285             HUF_DECODE_SYMBOLX4_2(op4, &bitD4);
2286             HUF_DECODE_SYMBOLX4_1(op1, &bitD1);
2287             HUF_DECODE_SYMBOLX4_1(op2, &bitD2);
2288             HUF_DECODE_SYMBOLX4_1(op3, &bitD3);
2289             HUF_DECODE_SYMBOLX4_1(op4, &bitD4);
2290             HUF_DECODE_SYMBOLX4_2(op1, &bitD1);
2291             HUF_DECODE_SYMBOLX4_2(op2, &bitD2);
2292             HUF_DECODE_SYMBOLX4_2(op3, &bitD3);
2293             HUF_DECODE_SYMBOLX4_2(op4, &bitD4);
2294             HUF_DECODE_SYMBOLX4_0(op1, &bitD1);
2295             HUF_DECODE_SYMBOLX4_0(op2, &bitD2);
2296             HUF_DECODE_SYMBOLX4_0(op3, &bitD3);
2297             HUF_DECODE_SYMBOLX4_0(op4, &bitD4);
2298 
2299             endSignal = BIT_reloadDStream(&bitD1) | BIT_reloadDStream(&bitD2) | BIT_reloadDStream(&bitD3) | BIT_reloadDStream(&bitD4);
2300         }
2301 
2302         /* check corruption */
2303         if (op1 > opStart2) return ERROR(corruption_detected);
2304         if (op2 > opStart3) return ERROR(corruption_detected);
2305         if (op3 > opStart4) return ERROR(corruption_detected);
2306         /* note : op4 supposed already verified within main loop */
2307 
2308         /* finish bitStreams one by one */
2309         HUF_decodeStreamX4(op1, &bitD1, opStart2, dt, dtLog);
2310         HUF_decodeStreamX4(op2, &bitD2, opStart3, dt, dtLog);
2311         HUF_decodeStreamX4(op3, &bitD3, opStart4, dt, dtLog);
2312         HUF_decodeStreamX4(op4, &bitD4, oend,     dt, dtLog);
2313 
2314         /* check */
2315         endSignal = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
2316         if (!endSignal) return ERROR(corruption_detected);
2317 
2318         /* decoded size */
2319         return dstSize;
2320     }
2321 }
2322 
2323 
2324 static size_t HUF_decompress4X4 (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
2325 {
2326     HUF_CREATE_STATIC_DTABLEX4(DTable, HUF_MAX_TABLELOG);
2327     const BYTE* ip = (const BYTE*) cSrc;
2328 
2329     size_t hSize = HUF_readDTableX4 (DTable, cSrc, cSrcSize);
2330     if (HUF_isError(hSize)) return hSize;
2331     if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
2332     ip += hSize;
2333     cSrcSize -= hSize;
2334 
2335     return HUF_decompress4X4_usingDTable (dst, dstSize, ip, cSrcSize, DTable);
2336 }
2337 
2338 
2339 /**********************************/
2340 /* Generic decompression selector */
2341 /**********************************/
2342 
2343 typedef struct { U32 tableTime; U32 decode256Time; } algo_time_t;
2344 static const algo_time_t algoTime[16 /* Quantization */][3 /* single, double, quad */] =
2345 {
2346     /* single, double, quad */
2347     {{0,0}, {1,1}, {2,2}},  /* Q==0 : impossible */
2348     {{0,0}, {1,1}, {2,2}},  /* Q==1 : impossible */
2349     {{  38,130}, {1313, 74}, {2151, 38}},   /* Q == 2 : 12-18% */
2350     {{ 448,128}, {1353, 74}, {2238, 41}},   /* Q == 3 : 18-25% */
2351     {{ 556,128}, {1353, 74}, {2238, 47}},   /* Q == 4 : 25-32% */
2352     {{ 714,128}, {1418, 74}, {2436, 53}},   /* Q == 5 : 32-38% */
2353     {{ 883,128}, {1437, 74}, {2464, 61}},   /* Q == 6 : 38-44% */
2354     {{ 897,128}, {1515, 75}, {2622, 68}},   /* Q == 7 : 44-50% */
2355     {{ 926,128}, {1613, 75}, {2730, 75}},   /* Q == 8 : 50-56% */
2356     {{ 947,128}, {1729, 77}, {3359, 77}},   /* Q == 9 : 56-62% */
2357     {{1107,128}, {2083, 81}, {4006, 84}},   /* Q ==10 : 62-69% */
2358     {{1177,128}, {2379, 87}, {4785, 88}},   /* Q ==11 : 69-75% */
2359     {{1242,128}, {2415, 93}, {5155, 84}},   /* Q ==12 : 75-81% */
2360     {{1349,128}, {2644,106}, {5260,106}},   /* Q ==13 : 81-87% */
2361     {{1455,128}, {2422,124}, {4174,124}},   /* Q ==14 : 87-93% */
2362     {{ 722,128}, {1891,145}, {1936,146}},   /* Q ==15 : 93-99% */
2363 };
2364 
2365 typedef size_t (*decompressionAlgo)(void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize);
2366 
2367 static size_t HUF_decompress (void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
2368 {
2369     static const decompressionAlgo decompress[3] = { HUF_decompress4X2, HUF_decompress4X4, NULL };
2370     /* estimate decompression time */
2371     U32 Q;
2372     const U32 D256 = (U32)(dstSize >> 8);
2373     U32 Dtime[3];
2374     U32 algoNb = 0;
2375     int n;
2376 
2377     /* validation checks */
2378     if (dstSize == 0) return ERROR(dstSize_tooSmall);
2379     if (cSrcSize > dstSize) return ERROR(corruption_detected);   /* invalid */
2380     if (cSrcSize == dstSize) { memcpy(dst, cSrc, dstSize); return dstSize; }   /* not compressed */
2381     if (cSrcSize == 1) { memset(dst, *(const BYTE*)cSrc, dstSize); return dstSize; }   /* RLE */
2382 
2383     /* decoder timing evaluation */
2384     Q = (U32)(cSrcSize * 16 / dstSize);   /* Q < 16 since dstSize > cSrcSize */
2385     for (n=0; n<3; n++)
2386         Dtime[n] = algoTime[Q][n].tableTime + (algoTime[Q][n].decode256Time * D256);
2387 
2388     Dtime[1] += Dtime[1] >> 4; Dtime[2] += Dtime[2] >> 3; /* advantage to algorithms using less memory, for cache eviction */
2389 
2390     if (Dtime[1] < Dtime[0]) algoNb = 1;
2391 
2392     return decompress[algoNb](dst, dstSize, cSrc, cSrcSize);
2393 
2394     //return HUF_decompress4X2(dst, dstSize, cSrc, cSrcSize);   /* multi-streams single-symbol decoding */
2395     //return HUF_decompress4X4(dst, dstSize, cSrc, cSrcSize);   /* multi-streams double-symbols decoding */
2396     //return HUF_decompress4X6(dst, dstSize, cSrc, cSrcSize);   /* multi-streams quad-symbols decoding */
2397 }
2398 
2399 
2400 
2401 #endif   /* ZSTD_CCOMMON_H_MODULE */
2402 
2403 
2404 /*
2405     zstd - decompression module fo v0.4 legacy format
2406     Copyright (C) 2015-2016, Yann Collet.
2407 
2408     BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
2409 
2410     Redistribution and use in source and binary forms, with or without
2411     modification, are permitted provided that the following conditions are
2412     met:
2413     * Redistributions of source code must retain the above copyright
2414     notice, this list of conditions and the following disclaimer.
2415     * Redistributions in binary form must reproduce the above
2416     copyright notice, this list of conditions and the following disclaimer
2417     in the documentation and/or other materials provided with the
2418     distribution.
2419     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
2420     "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
2421     LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
2422     A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
2423     OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
2424     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
2425     LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
2426     DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
2427     THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
2428     (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
2429     OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
2430 
2431     You can contact the author at :
2432     - zstd source repository : https://github.com/Cyan4973/zstd
2433     - ztsd public forum : https://groups.google.com/forum/#!forum/lz4c
2434 */
2435 
2436 /* ***************************************************************
2437 *  Tuning parameters
2438 *****************************************************************/
2439 /*!
2440  * HEAPMODE :
2441  * Select how default decompression function ZSTD_decompress() will allocate memory,
2442  * in memory stack (0), or in memory heap (1, requires malloc())
2443  */
2444 #ifndef ZSTD_HEAPMODE
2445 #  define ZSTD_HEAPMODE 1
2446 #endif
2447 
2448 
2449 /* *******************************************************
2450 *  Includes
2451 *********************************************************/
2452 #include <stdlib.h>      /* calloc */
2453 #include <string.h>      /* memcpy, memmove */
2454 #include <stdio.h>       /* debug : printf */
2455 
2456 
2457 /* *******************************************************
2458 *  Compiler specifics
2459 *********************************************************/
2460 #ifdef _MSC_VER    /* Visual Studio */
2461 #  include <intrin.h>                    /* For Visual 2005 */
2462 #  pragma warning(disable : 4127)        /* disable: C4127: conditional expression is constant */
2463 #  pragma warning(disable : 4324)        /* disable: C4324: padded structure */
2464 #endif
2465 
2466 
2467 /* *************************************
2468 *  Local types
2469 ***************************************/
2470 typedef struct
2471 {
2472     blockType_t blockType;
2473     U32 origSize;
2474 } blockProperties_t;
2475 
2476 
2477 /* *******************************************************
2478 *  Memory operations
2479 **********************************************************/
2480 static void ZSTD_copy4(void* dst, const void* src) { memcpy(dst, src, 4); }
2481 
2482 
2483 /* *************************************
2484 *  Error Management
2485 ***************************************/
2486 
2487 /*! ZSTD_isError
2488 *   tells if a return value is an error code */
2489 static unsigned ZSTD_isError(size_t code) { return ERR_isError(code); }
2490 
2491 
2492 /* *************************************************************
2493 *   Context management
2494 ***************************************************************/
2495 typedef enum { ZSTDds_getFrameHeaderSize, ZSTDds_decodeFrameHeader,
2496                ZSTDds_decodeBlockHeader, ZSTDds_decompressBlock } ZSTD_dStage;
2497 
2498 struct ZSTDv04_Dctx_s
2499 {
2500     U32 LLTable[FSE_DTABLE_SIZE_U32(LLFSELog)];
2501     U32 OffTable[FSE_DTABLE_SIZE_U32(OffFSELog)];
2502     U32 MLTable[FSE_DTABLE_SIZE_U32(MLFSELog)];
2503     const void* previousDstEnd;
2504     const void* base;
2505     const void* vBase;
2506     const void* dictEnd;
2507     size_t expected;
2508     size_t headerSize;
2509     ZSTD_parameters params;
2510     blockType_t bType;
2511     ZSTD_dStage stage;
2512     const BYTE* litPtr;
2513     size_t litSize;
2514     BYTE litBuffer[BLOCKSIZE + 8 /* margin for wildcopy */];
2515     BYTE headerBuffer[ZSTD_frameHeaderSize_max];
2516 };  /* typedef'd to ZSTD_DCtx within "zstd_static.h" */
2517 
2518 static size_t ZSTD_resetDCtx(ZSTD_DCtx* dctx)
2519 {
2520     dctx->expected = ZSTD_frameHeaderSize_min;
2521     dctx->stage = ZSTDds_getFrameHeaderSize;
2522     dctx->previousDstEnd = NULL;
2523     dctx->base = NULL;
2524     dctx->vBase = NULL;
2525     dctx->dictEnd = NULL;
2526     return 0;
2527 }
2528 
2529 static ZSTD_DCtx* ZSTD_createDCtx(void)
2530 {
2531     ZSTD_DCtx* dctx = (ZSTD_DCtx*)malloc(sizeof(ZSTD_DCtx));
2532     if (dctx==NULL) return NULL;
2533     ZSTD_resetDCtx(dctx);
2534     return dctx;
2535 }
2536 
2537 static size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx)
2538 {
2539     free(dctx);
2540     return 0;
2541 }
2542 
2543 
2544 /* *************************************************************
2545 *   Decompression section
2546 ***************************************************************/
2547 /** ZSTD_decodeFrameHeader_Part1
2548 *   decode the 1st part of the Frame Header, which tells Frame Header size.
2549 *   srcSize must be == ZSTD_frameHeaderSize_min
2550 *   @return : the full size of the Frame Header */
2551 static size_t ZSTD_decodeFrameHeader_Part1(ZSTD_DCtx* zc, const void* src, size_t srcSize)
2552 {
2553     U32 magicNumber;
2554     if (srcSize != ZSTD_frameHeaderSize_min) return ERROR(srcSize_wrong);
2555     magicNumber = MEM_readLE32(src);
2556     if (magicNumber != ZSTD_MAGICNUMBER) return ERROR(prefix_unknown);
2557     zc->headerSize = ZSTD_frameHeaderSize_min;
2558     return zc->headerSize;
2559 }
2560 
2561 
2562 static size_t ZSTD_getFrameParams(ZSTD_parameters* params, const void* src, size_t srcSize)
2563 {
2564     U32 magicNumber;
2565     if (srcSize < ZSTD_frameHeaderSize_min) return ZSTD_frameHeaderSize_max;
2566     magicNumber = MEM_readLE32(src);
2567     if (magicNumber != ZSTD_MAGICNUMBER) return ERROR(prefix_unknown);
2568     memset(params, 0, sizeof(*params));
2569     params->windowLog = (((const BYTE*)src)[4] & 15) + ZSTD_WINDOWLOG_ABSOLUTEMIN;
2570     if ((((const BYTE*)src)[4] >> 4) != 0) return ERROR(frameParameter_unsupported);   /* reserved bits */
2571     return 0;
2572 }
2573 
2574 /** ZSTD_decodeFrameHeader_Part2
2575 *   decode the full Frame Header
2576 *   srcSize must be the size provided by ZSTD_decodeFrameHeader_Part1
2577 *   @return : 0, or an error code, which can be tested using ZSTD_isError() */
2578 static size_t ZSTD_decodeFrameHeader_Part2(ZSTD_DCtx* zc, const void* src, size_t srcSize)
2579 {
2580     size_t result;
2581     if (srcSize != zc->headerSize) return ERROR(srcSize_wrong);
2582     result = ZSTD_getFrameParams(&(zc->params), src, srcSize);
2583     if ((MEM_32bits()) && (zc->params.windowLog > 25)) return ERROR(frameParameter_unsupported);
2584     return result;
2585 }
2586 
2587 
2588 static size_t ZSTD_getcBlockSize(const void* src, size_t srcSize, blockProperties_t* bpPtr)
2589 {
2590     const BYTE* const in = (const BYTE* const)src;
2591     BYTE headerFlags;
2592     U32 cSize;
2593 
2594     if (srcSize < 3) return ERROR(srcSize_wrong);
2595 
2596     headerFlags = *in;
2597     cSize = in[2] + (in[1]<<8) + ((in[0] & 7)<<16);
2598 
2599     bpPtr->blockType = (blockType_t)(headerFlags >> 6);
2600     bpPtr->origSize = (bpPtr->blockType == bt_rle) ? cSize : 0;
2601 
2602     if (bpPtr->blockType == bt_end) return 0;
2603     if (bpPtr->blockType == bt_rle) return 1;
2604     return cSize;
2605 }
2606 
2607 static size_t ZSTD_copyRawBlock(void* dst, size_t maxDstSize, const void* src, size_t srcSize)
2608 {
2609     if (srcSize > maxDstSize) return ERROR(dstSize_tooSmall);
2610     if (srcSize > 0) {
2611         memcpy(dst, src, srcSize);
2612     }
2613     return srcSize;
2614 }
2615 
2616 
2617 /** ZSTD_decompressLiterals
2618     @return : nb of bytes read from src, or an error code*/
2619 static size_t ZSTD_decompressLiterals(void* dst, size_t* maxDstSizePtr,
2620                                 const void* src, size_t srcSize)
2621 {
2622     const BYTE* ip = (const BYTE*)src;
2623 
2624     const size_t litSize = (MEM_readLE32(src) & 0x1FFFFF) >> 2;   /* no buffer issue : srcSize >= MIN_CBLOCK_SIZE */
2625     const size_t litCSize = (MEM_readLE32(ip+2) & 0xFFFFFF) >> 5;   /* no buffer issue : srcSize >= MIN_CBLOCK_SIZE */
2626 
2627     if (litSize > *maxDstSizePtr) return ERROR(corruption_detected);
2628     if (litCSize + 5 > srcSize) return ERROR(corruption_detected);
2629 
2630     if (HUF_isError(HUF_decompress(dst, litSize, ip+5, litCSize))) return ERROR(corruption_detected);
2631 
2632     *maxDstSizePtr = litSize;
2633     return litCSize + 5;
2634 }
2635 
2636 
2637 /** ZSTD_decodeLiteralsBlock
2638     @return : nb of bytes read from src (< srcSize ) */
2639 static size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx,
2640                           const void* src, size_t srcSize)   /* note : srcSize < BLOCKSIZE */
2641 {
2642     const BYTE* const istart = (const BYTE*) src;
2643 
2644     /* any compressed block with literals segment must be at least this size */
2645     if (srcSize < MIN_CBLOCK_SIZE) return ERROR(corruption_detected);
2646 
2647     switch(*istart & 3)
2648     {
2649     /* compressed */
2650     case 0:
2651         {
2652             size_t litSize = BLOCKSIZE;
2653             const size_t readSize = ZSTD_decompressLiterals(dctx->litBuffer, &litSize, src, srcSize);
2654             dctx->litPtr = dctx->litBuffer;
2655             dctx->litSize = litSize;
2656             memset(dctx->litBuffer + dctx->litSize, 0, 8);
2657             return readSize;   /* works if it's an error too */
2658         }
2659     case IS_RAW:
2660         {
2661             const size_t litSize = (MEM_readLE32(istart) & 0xFFFFFF) >> 2;   /* no buffer issue : srcSize >= MIN_CBLOCK_SIZE */
2662             if (litSize > srcSize-11)   /* risk of reading too far with wildcopy */
2663             {
2664                 if (litSize > BLOCKSIZE) return ERROR(corruption_detected);
2665                 if (litSize > srcSize-3) return ERROR(corruption_detected);
2666                 memcpy(dctx->litBuffer, istart, litSize);
2667                 dctx->litPtr = dctx->litBuffer;
2668                 dctx->litSize = litSize;
2669                 memset(dctx->litBuffer + dctx->litSize, 0, 8);
2670                 return litSize+3;
2671             }
2672             /* direct reference into compressed stream */
2673             dctx->litPtr = istart+3;
2674             dctx->litSize = litSize;
2675             return litSize+3;        }
2676     case IS_RLE:
2677         {
2678             const size_t litSize = (MEM_readLE32(istart) & 0xFFFFFF) >> 2;   /* no buffer issue : srcSize >= MIN_CBLOCK_SIZE */
2679             if (litSize > BLOCKSIZE) return ERROR(corruption_detected);
2680             memset(dctx->litBuffer, istart[3], litSize + 8);
2681             dctx->litPtr = dctx->litBuffer;
2682             dctx->litSize = litSize;
2683             return 4;
2684         }
2685     default:
2686         return ERROR(corruption_detected);   /* forbidden nominal case */
2687     }
2688 }
2689 
2690 
2691 static size_t ZSTD_decodeSeqHeaders(int* nbSeq, const BYTE** dumpsPtr, size_t* dumpsLengthPtr,
2692                          FSE_DTable* DTableLL, FSE_DTable* DTableML, FSE_DTable* DTableOffb,
2693                          const void* src, size_t srcSize)
2694 {
2695     const BYTE* const istart = (const BYTE* const)src;
2696     const BYTE* ip = istart;
2697     const BYTE* const iend = istart + srcSize;
2698     U32 LLtype, Offtype, MLtype;
2699     U32 LLlog, Offlog, MLlog;
2700     size_t dumpsLength;
2701 
2702     /* check */
2703     if (srcSize < 5) return ERROR(srcSize_wrong);
2704 
2705     /* SeqHead */
2706     *nbSeq = MEM_readLE16(ip); ip+=2;
2707     LLtype  = *ip >> 6;
2708     Offtype = (*ip >> 4) & 3;
2709     MLtype  = (*ip >> 2) & 3;
2710     if (*ip & 2)
2711     {
2712         dumpsLength  = ip[2];
2713         dumpsLength += ip[1] << 8;
2714         ip += 3;
2715     }
2716     else
2717     {
2718         dumpsLength  = ip[1];
2719         dumpsLength += (ip[0] & 1) << 8;
2720         ip += 2;
2721     }
2722     *dumpsPtr = ip;
2723     ip += dumpsLength;
2724     *dumpsLengthPtr = dumpsLength;
2725 
2726     /* check */
2727     if (ip > iend-3) return ERROR(srcSize_wrong); /* min : all 3 are "raw", hence no header, but at least xxLog bits per type */
2728 
2729     /* sequences */
2730     {
2731         S16 norm[MaxML+1];    /* assumption : MaxML >= MaxLL >= MaxOff */
2732         size_t headerSize;
2733 
2734         /* Build DTables */
2735         switch(LLtype)
2736         {
2737         case bt_rle :
2738             LLlog = 0;
2739             FSE_buildDTable_rle(DTableLL, *ip++); break;
2740         case bt_raw :
2741             LLlog = LLbits;
2742             FSE_buildDTable_raw(DTableLL, LLbits); break;
2743         default :
2744             {   U32 max = MaxLL;
2745                 headerSize = FSE_readNCount(norm, &max, &LLlog, ip, iend-ip);
2746                 if (FSE_isError(headerSize)) return ERROR(GENERIC);
2747                 if (LLlog > LLFSELog) return ERROR(corruption_detected);
2748                 ip += headerSize;
2749                 FSE_buildDTable(DTableLL, norm, max, LLlog);
2750         }   }
2751 
2752         switch(Offtype)
2753         {
2754         case bt_rle :
2755             Offlog = 0;
2756             if (ip > iend-2) return ERROR(srcSize_wrong);   /* min : "raw", hence no header, but at least xxLog bits */
2757             FSE_buildDTable_rle(DTableOffb, *ip++ & MaxOff); /* if *ip > MaxOff, data is corrupted */
2758             break;
2759         case bt_raw :
2760             Offlog = Offbits;
2761             FSE_buildDTable_raw(DTableOffb, Offbits); break;
2762         default :
2763             {   U32 max = MaxOff;
2764                 headerSize = FSE_readNCount(norm, &max, &Offlog, ip, iend-ip);
2765                 if (FSE_isError(headerSize)) return ERROR(GENERIC);
2766                 if (Offlog > OffFSELog) return ERROR(corruption_detected);
2767                 ip += headerSize;
2768                 FSE_buildDTable(DTableOffb, norm, max, Offlog);
2769         }   }
2770 
2771         switch(MLtype)
2772         {
2773         case bt_rle :
2774             MLlog = 0;
2775             if (ip > iend-2) return ERROR(srcSize_wrong); /* min : "raw", hence no header, but at least xxLog bits */
2776             FSE_buildDTable_rle(DTableML, *ip++); break;
2777         case bt_raw :
2778             MLlog = MLbits;
2779             FSE_buildDTable_raw(DTableML, MLbits); break;
2780         default :
2781             {   U32 max = MaxML;
2782                 headerSize = FSE_readNCount(norm, &max, &MLlog, ip, iend-ip);
2783                 if (FSE_isError(headerSize)) return ERROR(GENERIC);
2784                 if (MLlog > MLFSELog) return ERROR(corruption_detected);
2785                 ip += headerSize;
2786                 FSE_buildDTable(DTableML, norm, max, MLlog);
2787     }   }   }
2788 
2789     return ip-istart;
2790 }
2791 
2792 
2793 typedef struct {
2794     size_t litLength;
2795     size_t offset;
2796     size_t matchLength;
2797 } seq_t;
2798 
2799 typedef struct {
2800     BIT_DStream_t DStream;
2801     FSE_DState_t stateLL;
2802     FSE_DState_t stateOffb;
2803     FSE_DState_t stateML;
2804     size_t prevOffset;
2805     const BYTE* dumps;
2806     const BYTE* dumpsEnd;
2807 } seqState_t;
2808 
2809 
2810 static void ZSTD_decodeSequence(seq_t* seq, seqState_t* seqState)
2811 {
2812     size_t litLength;
2813     size_t prevOffset;
2814     size_t offset;
2815     size_t matchLength;
2816     const BYTE* dumps = seqState->dumps;
2817     const BYTE* const de = seqState->dumpsEnd;
2818 
2819     /* Literal length */
2820     litLength = FSE_decodeSymbol(&(seqState->stateLL), &(seqState->DStream));
2821     prevOffset = litLength ? seq->offset : seqState->prevOffset;
2822     if (litLength == MaxLL) {
2823         const U32 add = dumps<de ? *dumps++ : 0;
2824         if (add < 255) litLength += add;
2825         else if (dumps + 3 <= de) {
2826             litLength = MEM_readLE24(dumps);
2827             dumps += 3;
2828         }
2829         if (dumps >= de) { dumps = de-1; }  /* late correction, to avoid read overflow (data is now corrupted anyway) */
2830     }
2831 
2832     /* Offset */
2833     {   static const U32 offsetPrefix[MaxOff+1] = {
2834                 1 /*fake*/, 1, 2, 4, 8, 16, 32, 64, 128, 256,
2835                 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 131072, 262144,
2836                 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, /*fake*/ 1, 1, 1, 1, 1 };
2837         U32 offsetCode, nbBits;
2838         offsetCode = FSE_decodeSymbol(&(seqState->stateOffb), &(seqState->DStream));   /* <= maxOff, by table construction */
2839         if (MEM_32bits()) BIT_reloadDStream(&(seqState->DStream));
2840         nbBits = offsetCode - 1;
2841         if (offsetCode==0) nbBits = 0;   /* cmove */
2842         offset = offsetPrefix[offsetCode] + BIT_readBits(&(seqState->DStream), nbBits);
2843         if (MEM_32bits()) BIT_reloadDStream(&(seqState->DStream));
2844         if (offsetCode==0) offset = prevOffset;   /* cmove */
2845         if (offsetCode | !litLength) seqState->prevOffset = seq->offset;   /* cmove */
2846     }
2847 
2848     /* MatchLength */
2849     matchLength = FSE_decodeSymbol(&(seqState->stateML), &(seqState->DStream));
2850     if (matchLength == MaxML) {
2851         const U32 add = dumps<de ? *dumps++ : 0;
2852         if (add < 255) matchLength += add;
2853         else if (dumps + 3 <= de){
2854             matchLength = MEM_readLE24(dumps);
2855             dumps += 3;
2856         }
2857         if (dumps >= de) { dumps = de-1; }  /* late correction, to avoid read overflow (data is now corrupted anyway) */
2858     }
2859     matchLength += MINMATCH;
2860 
2861     /* save result */
2862     seq->litLength = litLength;
2863     seq->offset = offset;
2864     seq->matchLength = matchLength;
2865     seqState->dumps = dumps;
2866 }
2867 
2868 
2869 static size_t ZSTD_execSequence(BYTE* op,
2870                                 BYTE* const oend, seq_t sequence,
2871                                 const BYTE** litPtr, const BYTE* const litLimit,
2872                                 const BYTE* const base, const BYTE* const vBase, const BYTE* const dictEnd)
2873 {
2874     static const int dec32table[] = { 0, 1, 2, 1, 4, 4, 4, 4 };   /* added */
2875     static const int dec64table[] = { 8, 8, 8, 7, 8, 9,10,11 };   /* subtracted */
2876     BYTE* const oLitEnd = op + sequence.litLength;
2877     const size_t sequenceLength = sequence.litLength + sequence.matchLength;
2878     BYTE* const oMatchEnd = op + sequenceLength;   /* risk : address space overflow (32-bits) */
2879     BYTE* const oend_8 = oend-8;
2880     const BYTE* const litEnd = *litPtr + sequence.litLength;
2881     const BYTE* match = oLitEnd - sequence.offset;
2882 
2883     /* check */
2884     if (oLitEnd > oend_8) return ERROR(dstSize_tooSmall);   /* last match must start at a minimum distance of 8 from oend */
2885     if (oMatchEnd > oend) return ERROR(dstSize_tooSmall);   /* overwrite beyond dst buffer */
2886     if (litEnd > litLimit) return ERROR(corruption_detected);   /* risk read beyond lit buffer */
2887 
2888     /* copy Literals */
2889     ZSTD_wildcopy(op, *litPtr, sequence.litLength);   /* note : oLitEnd <= oend-8 : no risk of overwrite beyond oend */
2890     op = oLitEnd;
2891     *litPtr = litEnd;   /* update for next sequence */
2892 
2893     /* copy Match */
2894     if (sequence.offset > (size_t)(oLitEnd - base))
2895     {
2896         /* offset beyond prefix */
2897         if (sequence.offset > (size_t)(oLitEnd - vBase))
2898             return ERROR(corruption_detected);
2899         match = dictEnd - (base-match);
2900         if (match + sequence.matchLength <= dictEnd)
2901         {
2902             memmove(oLitEnd, match, sequence.matchLength);
2903             return sequenceLength;
2904         }
2905         /* span extDict & currentPrefixSegment */
2906         {
2907             size_t length1 = dictEnd - match;
2908             memmove(oLitEnd, match, length1);
2909             op = oLitEnd + length1;
2910             sequence.matchLength -= length1;
2911             match = base;
2912             if (op > oend_8 || sequence.matchLength < MINMATCH) {
2913               while (op < oMatchEnd) *op++ = *match++;
2914               return sequenceLength;
2915             }
2916         }
2917     }
2918     /* Requirement: op <= oend_8 */
2919 
2920     /* match within prefix */
2921     if (sequence.offset < 8) {
2922         /* close range match, overlap */
2923         const int sub2 = dec64table[sequence.offset];
2924         op[0] = match[0];
2925         op[1] = match[1];
2926         op[2] = match[2];
2927         op[3] = match[3];
2928         match += dec32table[sequence.offset];
2929         ZSTD_copy4(op+4, match);
2930         match -= sub2;
2931     } else {
2932         ZSTD_copy8(op, match);
2933     }
2934     op += 8; match += 8;
2935 
2936     if (oMatchEnd > oend-(16-MINMATCH))
2937     {
2938         if (op < oend_8)
2939         {
2940             ZSTD_wildcopy(op, match, oend_8 - op);
2941             match += oend_8 - op;
2942             op = oend_8;
2943         }
2944         while (op < oMatchEnd) *op++ = *match++;
2945     }
2946     else
2947     {
2948         ZSTD_wildcopy(op, match, (ptrdiff_t)sequence.matchLength-8);   /* works even if matchLength < 8, but must be signed */
2949     }
2950     return sequenceLength;
2951 }
2952 
2953 
2954 static size_t ZSTD_decompressSequences(
2955                                ZSTD_DCtx* dctx,
2956                                void* dst, size_t maxDstSize,
2957                          const void* seqStart, size_t seqSize)
2958 {
2959     const BYTE* ip = (const BYTE*)seqStart;
2960     const BYTE* const iend = ip + seqSize;
2961     BYTE* const ostart = (BYTE* const)dst;
2962     BYTE* op = ostart;
2963     BYTE* const oend = ostart + maxDstSize;
2964     size_t errorCode, dumpsLength;
2965     const BYTE* litPtr = dctx->litPtr;
2966     const BYTE* const litEnd = litPtr + dctx->litSize;
2967     int nbSeq;
2968     const BYTE* dumps;
2969     U32* DTableLL = dctx->LLTable;
2970     U32* DTableML = dctx->MLTable;
2971     U32* DTableOffb = dctx->OffTable;
2972     const BYTE* const base = (const BYTE*) (dctx->base);
2973     const BYTE* const vBase = (const BYTE*) (dctx->vBase);
2974     const BYTE* const dictEnd = (const BYTE*) (dctx->dictEnd);
2975 
2976     /* Build Decoding Tables */
2977     errorCode = ZSTD_decodeSeqHeaders(&nbSeq, &dumps, &dumpsLength,
2978                                       DTableLL, DTableML, DTableOffb,
2979                                       ip, iend-ip);
2980     if (ZSTD_isError(errorCode)) return errorCode;
2981     ip += errorCode;
2982 
2983     /* Regen sequences */
2984     {
2985         seq_t sequence;
2986         seqState_t seqState;
2987 
2988         memset(&sequence, 0, sizeof(sequence));
2989         sequence.offset = 4;
2990         seqState.dumps = dumps;
2991         seqState.dumpsEnd = dumps + dumpsLength;
2992         seqState.prevOffset = 4;
2993         errorCode = BIT_initDStream(&(seqState.DStream), ip, iend-ip);
2994         if (ERR_isError(errorCode)) return ERROR(corruption_detected);
2995         FSE_initDState(&(seqState.stateLL), &(seqState.DStream), DTableLL);
2996         FSE_initDState(&(seqState.stateOffb), &(seqState.DStream), DTableOffb);
2997         FSE_initDState(&(seqState.stateML), &(seqState.DStream), DTableML);
2998 
2999         for ( ; (BIT_reloadDStream(&(seqState.DStream)) <= BIT_DStream_completed) && nbSeq ; )
3000         {
3001             size_t oneSeqSize;
3002             nbSeq--;
3003             ZSTD_decodeSequence(&sequence, &seqState);
3004             oneSeqSize = ZSTD_execSequence(op, oend, sequence, &litPtr, litEnd, base, vBase, dictEnd);
3005             if (ZSTD_isError(oneSeqSize)) return oneSeqSize;
3006             op += oneSeqSize;
3007         }
3008 
3009         /* check if reached exact end */
3010         if ( !BIT_endOfDStream(&(seqState.DStream)) ) return ERROR(corruption_detected);   /* DStream should be entirely and exactly consumed; otherwise data is corrupted */
3011 
3012         /* last literal segment */
3013         {
3014             size_t lastLLSize = litEnd - litPtr;
3015             if (litPtr > litEnd) return ERROR(corruption_detected);
3016             if (op+lastLLSize > oend) return ERROR(dstSize_tooSmall);
3017             if (lastLLSize > 0) {
3018                 if (op != litPtr) memcpy(op, litPtr, lastLLSize);
3019                 op += lastLLSize;
3020             }
3021         }
3022     }
3023 
3024     return op-ostart;
3025 }
3026 
3027 
3028 static void ZSTD_checkContinuity(ZSTD_DCtx* dctx, const void* dst)
3029 {
3030     if (dst != dctx->previousDstEnd)   /* not contiguous */
3031     {
3032         dctx->dictEnd = dctx->previousDstEnd;
3033         dctx->vBase = (const char*)dst - ((const char*)(dctx->previousDstEnd) - (const char*)(dctx->base));
3034         dctx->base = dst;
3035         dctx->previousDstEnd = dst;
3036     }
3037 }
3038 
3039 
3040 static size_t ZSTD_decompressBlock_internal(ZSTD_DCtx* dctx,
3041                             void* dst, size_t maxDstSize,
3042                       const void* src, size_t srcSize)
3043 {
3044     /* blockType == blockCompressed */
3045     const BYTE* ip = (const BYTE*)src;
3046     size_t litCSize;
3047 
3048     if (srcSize > BLOCKSIZE) return ERROR(corruption_detected);
3049 
3050     /* Decode literals sub-block */
3051     litCSize = ZSTD_decodeLiteralsBlock(dctx, src, srcSize);
3052     if (ZSTD_isError(litCSize)) return litCSize;
3053     ip += litCSize;
3054     srcSize -= litCSize;
3055 
3056     return ZSTD_decompressSequences(dctx, dst, maxDstSize, ip, srcSize);
3057 }
3058 
3059 
3060 static size_t ZSTD_decompress_usingDict(ZSTD_DCtx* ctx,
3061                                  void* dst, size_t maxDstSize,
3062                                  const void* src, size_t srcSize,
3063                                  const void* dict, size_t dictSize)
3064 {
3065     const BYTE* ip = (const BYTE*)src;
3066     const BYTE* iend = ip + srcSize;
3067     BYTE* const ostart = (BYTE* const)dst;
3068     BYTE* op = ostart;
3069     BYTE* const oend = ostart + maxDstSize;
3070     size_t remainingSize = srcSize;
3071     blockProperties_t blockProperties;
3072 
3073     /* init */
3074     ZSTD_resetDCtx(ctx);
3075     if (dict)
3076     {
3077         ZSTD_decompress_insertDictionary(ctx, dict, dictSize);
3078         ctx->dictEnd = ctx->previousDstEnd;
3079         ctx->vBase = (const char*)dst - ((const char*)(ctx->previousDstEnd) - (const char*)(ctx->base));
3080         ctx->base = dst;
3081     }
3082     else
3083     {
3084         ctx->vBase = ctx->base = ctx->dictEnd = dst;
3085     }
3086 
3087     /* Frame Header */
3088     {
3089         size_t frameHeaderSize;
3090         if (srcSize < ZSTD_frameHeaderSize_min+ZSTD_blockHeaderSize) return ERROR(srcSize_wrong);
3091         frameHeaderSize = ZSTD_decodeFrameHeader_Part1(ctx, src, ZSTD_frameHeaderSize_min);
3092         if (ZSTD_isError(frameHeaderSize)) return frameHeaderSize;
3093         if (srcSize < frameHeaderSize+ZSTD_blockHeaderSize) return ERROR(srcSize_wrong);
3094         ip += frameHeaderSize; remainingSize -= frameHeaderSize;
3095         frameHeaderSize = ZSTD_decodeFrameHeader_Part2(ctx, src, frameHeaderSize);
3096         if (ZSTD_isError(frameHeaderSize)) return frameHeaderSize;
3097     }
3098 
3099     /* Loop on each block */
3100     while (1)
3101     {
3102         size_t decodedSize=0;
3103         size_t cBlockSize = ZSTD_getcBlockSize(ip, iend-ip, &blockProperties);
3104         if (ZSTD_isError(cBlockSize)) return cBlockSize;
3105 
3106         ip += ZSTD_blockHeaderSize;
3107         remainingSize -= ZSTD_blockHeaderSize;
3108         if (cBlockSize > remainingSize) return ERROR(srcSize_wrong);
3109 
3110         switch(blockProperties.blockType)
3111         {
3112         case bt_compressed:
3113             decodedSize = ZSTD_decompressBlock_internal(ctx, op, oend-op, ip, cBlockSize);
3114             break;
3115         case bt_raw :
3116             decodedSize = ZSTD_copyRawBlock(op, oend-op, ip, cBlockSize);
3117             break;
3118         case bt_rle :
3119             return ERROR(GENERIC);   /* not yet supported */
3120             break;
3121         case bt_end :
3122             /* end of frame */
3123             if (remainingSize) return ERROR(srcSize_wrong);
3124             break;
3125         default:
3126             return ERROR(GENERIC);   /* impossible */
3127         }
3128         if (cBlockSize == 0) break;   /* bt_end */
3129 
3130         if (ZSTD_isError(decodedSize)) return decodedSize;
3131         op += decodedSize;
3132         ip += cBlockSize;
3133         remainingSize -= cBlockSize;
3134     }
3135 
3136     return op-ostart;
3137 }
3138 
3139 /* ZSTD_errorFrameSizeInfoLegacy() :
3140    assumes `cSize` and `dBound` are _not_ NULL */
3141 static void ZSTD_errorFrameSizeInfoLegacy(size_t* cSize, unsigned long long* dBound, size_t ret)
3142 {
3143     *cSize = ret;
3144     *dBound = ZSTD_CONTENTSIZE_ERROR;
3145 }
3146 
3147 void ZSTDv04_findFrameSizeInfoLegacy(const void *src, size_t srcSize, size_t* cSize, unsigned long long* dBound)
3148 {
3149     const BYTE* ip = (const BYTE*)src;
3150     size_t remainingSize = srcSize;
3151     size_t nbBlocks = 0;
3152     blockProperties_t blockProperties;
3153 
3154     /* Frame Header */
3155     if (srcSize < ZSTD_frameHeaderSize_min) {
3156         ZSTD_errorFrameSizeInfoLegacy(cSize, dBound, ERROR(srcSize_wrong));
3157         return;
3158     }
3159     if (MEM_readLE32(src) != ZSTD_MAGICNUMBER) {
3160         ZSTD_errorFrameSizeInfoLegacy(cSize, dBound, ERROR(prefix_unknown));
3161         return;
3162     }
3163     ip += ZSTD_frameHeaderSize_min; remainingSize -= ZSTD_frameHeaderSize_min;
3164 
3165     /* Loop on each block */
3166     while (1)
3167     {
3168         size_t cBlockSize = ZSTD_getcBlockSize(ip, remainingSize, &blockProperties);
3169         if (ZSTD_isError(cBlockSize)) {
3170             ZSTD_errorFrameSizeInfoLegacy(cSize, dBound, cBlockSize);
3171             return;
3172         }
3173 
3174         ip += ZSTD_blockHeaderSize;
3175         remainingSize -= ZSTD_blockHeaderSize;
3176         if (cBlockSize > remainingSize) {
3177             ZSTD_errorFrameSizeInfoLegacy(cSize, dBound, ERROR(srcSize_wrong));
3178             return;
3179         }
3180 
3181         if (cBlockSize == 0) break;   /* bt_end */
3182 
3183         ip += cBlockSize;
3184         remainingSize -= cBlockSize;
3185         nbBlocks++;
3186     }
3187 
3188     *cSize = ip - (const BYTE*)src;
3189     *dBound = nbBlocks * BLOCKSIZE;
3190 }
3191 
3192 /* ******************************
3193 *  Streaming Decompression API
3194 ********************************/
3195 static size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx* dctx)
3196 {
3197     return dctx->expected;
3198 }
3199 
3200 static size_t ZSTD_decompressContinue(ZSTD_DCtx* ctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize)
3201 {
3202     /* Sanity check */
3203     if (srcSize != ctx->expected) return ERROR(srcSize_wrong);
3204     ZSTD_checkContinuity(ctx, dst);
3205 
3206     /* Decompress : frame header; part 1 */
3207     switch (ctx->stage)
3208     {
3209     case ZSTDds_getFrameHeaderSize :
3210         /* get frame header size */
3211         if (srcSize != ZSTD_frameHeaderSize_min) return ERROR(srcSize_wrong);   /* impossible */
3212         ctx->headerSize = ZSTD_decodeFrameHeader_Part1(ctx, src, ZSTD_frameHeaderSize_min);
3213         if (ZSTD_isError(ctx->headerSize)) return ctx->headerSize;
3214         memcpy(ctx->headerBuffer, src, ZSTD_frameHeaderSize_min);
3215         if (ctx->headerSize > ZSTD_frameHeaderSize_min) return ERROR(GENERIC);   /* impossible */
3216         ctx->expected = 0;   /* not necessary to copy more */
3217         /* fallthrough */
3218     case ZSTDds_decodeFrameHeader:
3219         /* get frame header */
3220         {   size_t const result = ZSTD_decodeFrameHeader_Part2(ctx, ctx->headerBuffer, ctx->headerSize);
3221             if (ZSTD_isError(result)) return result;
3222             ctx->expected = ZSTD_blockHeaderSize;
3223             ctx->stage = ZSTDds_decodeBlockHeader;
3224             return 0;
3225         }
3226     case ZSTDds_decodeBlockHeader:
3227         /* Decode block header */
3228         {   blockProperties_t bp;
3229             size_t const blockSize = ZSTD_getcBlockSize(src, ZSTD_blockHeaderSize, &bp);
3230             if (ZSTD_isError(blockSize)) return blockSize;
3231             if (bp.blockType == bt_end)
3232             {
3233                 ctx->expected = 0;
3234                 ctx->stage = ZSTDds_getFrameHeaderSize;
3235             }
3236             else
3237             {
3238                 ctx->expected = blockSize;
3239                 ctx->bType = bp.blockType;
3240                 ctx->stage = ZSTDds_decompressBlock;
3241             }
3242             return 0;
3243         }
3244     case ZSTDds_decompressBlock:
3245         {
3246             /* Decompress : block content */
3247             size_t rSize;
3248             switch(ctx->bType)
3249             {
3250             case bt_compressed:
3251                 rSize = ZSTD_decompressBlock_internal(ctx, dst, maxDstSize, src, srcSize);
3252                 break;
3253             case bt_raw :
3254                 rSize = ZSTD_copyRawBlock(dst, maxDstSize, src, srcSize);
3255                 break;
3256             case bt_rle :
3257                 return ERROR(GENERIC);   /* not yet handled */
3258                 break;
3259             case bt_end :   /* should never happen (filtered at phase 1) */
3260                 rSize = 0;
3261                 break;
3262             default:
3263                 return ERROR(GENERIC);
3264             }
3265             ctx->stage = ZSTDds_decodeBlockHeader;
3266             ctx->expected = ZSTD_blockHeaderSize;
3267             ctx->previousDstEnd = (char*)dst + rSize;
3268             return rSize;
3269         }
3270     default:
3271         return ERROR(GENERIC);   /* impossible */
3272     }
3273 }
3274 
3275 
3276 static void ZSTD_decompress_insertDictionary(ZSTD_DCtx* ctx, const void* dict, size_t dictSize)
3277 {
3278     ctx->dictEnd = ctx->previousDstEnd;
3279     ctx->vBase = (const char*)dict - ((const char*)(ctx->previousDstEnd) - (const char*)(ctx->base));
3280     ctx->base = dict;
3281     ctx->previousDstEnd = (const char*)dict + dictSize;
3282 }
3283 
3284 
3285 
3286 /*
3287     Buffered version of Zstd compression library
3288     Copyright (C) 2015, Yann Collet.
3289 
3290     BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
3291 
3292     Redistribution and use in source and binary forms, with or without
3293     modification, are permitted provided that the following conditions are
3294     met:
3295     * Redistributions of source code must retain the above copyright
3296     notice, this list of conditions and the following disclaimer.
3297     * Redistributions in binary form must reproduce the above
3298     copyright notice, this list of conditions and the following disclaimer
3299     in the documentation and/or other materials provided with the
3300     distribution.
3301     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
3302     "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
3303     LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
3304     A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
3305     OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
3306     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
3307     LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
3308     DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
3309     THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
3310     (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
3311     OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
3312 
3313     You can contact the author at :
3314     - zstd source repository : https://github.com/Cyan4973/zstd
3315     - ztsd public forum : https://groups.google.com/forum/#!forum/lz4c
3316 */
3317 
3318 /* The objects defined into this file should be considered experimental.
3319  * They are not labelled stable, as their prototype may change in the future.
3320  * You can use them for tests, provide feedback, or if you can endure risk of future changes.
3321  */
3322 
3323 /* *************************************
3324 *  Includes
3325 ***************************************/
3326 #include <stdlib.h>
3327 
3328 
3329 /** ************************************************
3330 *  Streaming decompression
3331 *
3332 *  A ZBUFF_DCtx object is required to track streaming operation.
3333 *  Use ZBUFF_createDCtx() and ZBUFF_freeDCtx() to create/release resources.
3334 *  Use ZBUFF_decompressInit() to start a new decompression operation.
3335 *  ZBUFF_DCtx objects can be reused multiple times.
3336 *
3337 *  Use ZBUFF_decompressContinue() repetitively to consume your input.
3338 *  *srcSizePtr and *maxDstSizePtr can be any size.
3339 *  The function will report how many bytes were read or written by modifying *srcSizePtr and *maxDstSizePtr.
3340 *  Note that it may not consume the entire input, in which case it's up to the caller to call again the function with remaining input.
3341 *  The content of dst will be overwritten (up to *maxDstSizePtr) at each function call, so save its content if it matters or change dst .
3342 *  return : a hint to preferred nb of bytes to use as input for next function call (it's only a hint, to improve latency)
3343 *            or 0 when a frame is completely decoded
3344 *            or an error code, which can be tested using ZBUFF_isError().
3345 *
3346 *  Hint : recommended buffer sizes (not compulsory)
3347 *  output : 128 KB block size is the internal unit, it ensures it's always possible to write a full block when it's decoded.
3348 *  input : just follow indications from ZBUFF_decompressContinue() to minimize latency. It should always be <= 128 KB + 3 .
3349 * **************************************************/
3350 
3351 typedef enum { ZBUFFds_init, ZBUFFds_readHeader, ZBUFFds_loadHeader, ZBUFFds_decodeHeader,
3352                ZBUFFds_read, ZBUFFds_load, ZBUFFds_flush } ZBUFF_dStage;
3353 
3354 /* *** Resource management *** */
3355 
3356 #define ZSTD_frameHeaderSize_max 5   /* too magical, should come from reference */
3357 struct ZBUFFv04_DCtx_s {
3358     ZSTD_DCtx* zc;
3359     ZSTD_parameters params;
3360     char* inBuff;
3361     size_t inBuffSize;
3362     size_t inPos;
3363     char* outBuff;
3364     size_t outBuffSize;
3365     size_t outStart;
3366     size_t outEnd;
3367     size_t hPos;
3368     const char* dict;
3369     size_t dictSize;
3370     ZBUFF_dStage stage;
3371     unsigned char headerBuffer[ZSTD_frameHeaderSize_max];
3372 };   /* typedef'd to ZBUFF_DCtx within "zstd_buffered.h" */
3373 
3374 typedef ZBUFFv04_DCtx ZBUFF_DCtx;
3375 
3376 
3377 static ZBUFF_DCtx* ZBUFF_createDCtx(void)
3378 {
3379     ZBUFF_DCtx* zbc = (ZBUFF_DCtx*)malloc(sizeof(ZBUFF_DCtx));
3380     if (zbc==NULL) return NULL;
3381     memset(zbc, 0, sizeof(*zbc));
3382     zbc->zc = ZSTD_createDCtx();
3383     zbc->stage = ZBUFFds_init;
3384     return zbc;
3385 }
3386 
3387 static size_t ZBUFF_freeDCtx(ZBUFF_DCtx* zbc)
3388 {
3389     if (zbc==NULL) return 0;   /* support free on null */
3390     ZSTD_freeDCtx(zbc->zc);
3391     free(zbc->inBuff);
3392     free(zbc->outBuff);
3393     free(zbc);
3394     return 0;
3395 }
3396 
3397 
3398 /* *** Initialization *** */
3399 
3400 static size_t ZBUFF_decompressInit(ZBUFF_DCtx* zbc)
3401 {
3402     zbc->stage = ZBUFFds_readHeader;
3403     zbc->hPos = zbc->inPos = zbc->outStart = zbc->outEnd = zbc->dictSize = 0;
3404     return ZSTD_resetDCtx(zbc->zc);
3405 }
3406 
3407 
3408 static size_t ZBUFF_decompressWithDictionary(ZBUFF_DCtx* zbc, const void* src, size_t srcSize)
3409 {
3410     zbc->dict = (const char*)src;
3411     zbc->dictSize = srcSize;
3412     return 0;
3413 }
3414 
3415 static size_t ZBUFF_limitCopy(void* dst, size_t maxDstSize, const void* src, size_t srcSize)
3416 {
3417     size_t length = MIN(maxDstSize, srcSize);
3418     if (length > 0) {
3419         memcpy(dst, src, length);
3420     }
3421     return length;
3422 }
3423 
3424 /* *** Decompression *** */
3425 
3426 static size_t ZBUFF_decompressContinue(ZBUFF_DCtx* zbc, void* dst, size_t* maxDstSizePtr, const void* src, size_t* srcSizePtr)
3427 {
3428     const char* const istart = (const char*)src;
3429     const char* ip = istart;
3430     const char* const iend = istart + *srcSizePtr;
3431     char* const ostart = (char*)dst;
3432     char* op = ostart;
3433     char* const oend = ostart + *maxDstSizePtr;
3434     U32 notDone = 1;
3435 
3436     DEBUGLOG(5, "ZBUFF_decompressContinue");
3437     while (notDone)
3438     {
3439         switch(zbc->stage)
3440         {
3441 
3442         case ZBUFFds_init :
3443             DEBUGLOG(5, "ZBUFF_decompressContinue: stage==ZBUFFds_init => ERROR(init_missing)");
3444             return ERROR(init_missing);
3445 
3446         case ZBUFFds_readHeader :
3447             /* read header from src */
3448             {   size_t const headerSize = ZSTD_getFrameParams(&(zbc->params), src, *srcSizePtr);
3449                 if (ZSTD_isError(headerSize)) return headerSize;
3450                 if (headerSize) {
3451                     /* not enough input to decode header : tell how many bytes would be necessary */
3452                     memcpy(zbc->headerBuffer+zbc->hPos, src, *srcSizePtr);
3453                     zbc->hPos += *srcSizePtr;
3454                     *maxDstSizePtr = 0;
3455                     zbc->stage = ZBUFFds_loadHeader;
3456                     return headerSize - zbc->hPos;
3457                 }
3458                 zbc->stage = ZBUFFds_decodeHeader;
3459                 break;
3460             }
3461 
3462         case ZBUFFds_loadHeader:
3463             /* complete header from src */
3464             {   size_t headerSize = ZBUFF_limitCopy(
3465                     zbc->headerBuffer + zbc->hPos, ZSTD_frameHeaderSize_max - zbc->hPos,
3466                     src, *srcSizePtr);
3467                 zbc->hPos += headerSize;
3468                 ip += headerSize;
3469                 headerSize = ZSTD_getFrameParams(&(zbc->params), zbc->headerBuffer, zbc->hPos);
3470                 if (ZSTD_isError(headerSize)) return headerSize;
3471                 if (headerSize) {
3472                     /* not enough input to decode header : tell how many bytes would be necessary */
3473                     *maxDstSizePtr = 0;
3474                     return headerSize - zbc->hPos;
3475             }   }
3476             /* intentional fallthrough */
3477 
3478         case ZBUFFds_decodeHeader:
3479                 /* apply header to create / resize buffers */
3480                 {   size_t const neededOutSize = (size_t)1 << zbc->params.windowLog;
3481                     size_t const neededInSize = BLOCKSIZE;   /* a block is never > BLOCKSIZE */
3482                     if (zbc->inBuffSize < neededInSize) {
3483                         free(zbc->inBuff);
3484                         zbc->inBuffSize = neededInSize;
3485                         zbc->inBuff = (char*)malloc(neededInSize);
3486                         if (zbc->inBuff == NULL) return ERROR(memory_allocation);
3487                     }
3488                     if (zbc->outBuffSize < neededOutSize) {
3489                         free(zbc->outBuff);
3490                         zbc->outBuffSize = neededOutSize;
3491                         zbc->outBuff = (char*)malloc(neededOutSize);
3492                         if (zbc->outBuff == NULL) return ERROR(memory_allocation);
3493                 }   }
3494                 if (zbc->dictSize)
3495                     ZSTD_decompress_insertDictionary(zbc->zc, zbc->dict, zbc->dictSize);
3496                 if (zbc->hPos) {
3497                     /* some data already loaded into headerBuffer : transfer into inBuff */
3498                     memcpy(zbc->inBuff, zbc->headerBuffer, zbc->hPos);
3499                     zbc->inPos = zbc->hPos;
3500                     zbc->hPos = 0;
3501                     zbc->stage = ZBUFFds_load;
3502                     break;
3503                 }
3504                 zbc->stage = ZBUFFds_read;
3505 		/* fall-through */
3506         case ZBUFFds_read:
3507             {
3508                 size_t neededInSize = ZSTD_nextSrcSizeToDecompress(zbc->zc);
3509                 if (neededInSize==0)   /* end of frame */
3510                 {
3511                     zbc->stage = ZBUFFds_init;
3512                     notDone = 0;
3513                     break;
3514                 }
3515                 if ((size_t)(iend-ip) >= neededInSize)
3516                 {
3517                     /* directly decode from src */
3518                     size_t decodedSize = ZSTD_decompressContinue(zbc->zc,
3519                         zbc->outBuff + zbc->outStart, zbc->outBuffSize - zbc->outStart,
3520                         ip, neededInSize);
3521                     if (ZSTD_isError(decodedSize)) return decodedSize;
3522                     ip += neededInSize;
3523                     if (!decodedSize) break;   /* this was just a header */
3524                     zbc->outEnd = zbc->outStart +  decodedSize;
3525                     zbc->stage = ZBUFFds_flush;
3526                     break;
3527                 }
3528                 if (ip==iend) { notDone = 0; break; }   /* no more input */
3529                 zbc->stage = ZBUFFds_load;
3530             }
3531 	    /* fall-through */
3532         case ZBUFFds_load:
3533             {
3534                 size_t neededInSize = ZSTD_nextSrcSizeToDecompress(zbc->zc);
3535                 size_t toLoad = neededInSize - zbc->inPos;   /* should always be <= remaining space within inBuff */
3536                 size_t loadedSize;
3537                 if (toLoad > zbc->inBuffSize - zbc->inPos) return ERROR(corruption_detected);   /* should never happen */
3538                 loadedSize = ZBUFF_limitCopy(zbc->inBuff + zbc->inPos, toLoad, ip, iend-ip);
3539                 ip += loadedSize;
3540                 zbc->inPos += loadedSize;
3541                 if (loadedSize < toLoad) { notDone = 0; break; }   /* not enough input, wait for more */
3542                 {
3543                     size_t decodedSize = ZSTD_decompressContinue(zbc->zc,
3544                         zbc->outBuff + zbc->outStart, zbc->outBuffSize - zbc->outStart,
3545                         zbc->inBuff, neededInSize);
3546                     if (ZSTD_isError(decodedSize)) return decodedSize;
3547                     zbc->inPos = 0;   /* input is consumed */
3548                     if (!decodedSize) { zbc->stage = ZBUFFds_read; break; }   /* this was just a header */
3549                     zbc->outEnd = zbc->outStart +  decodedSize;
3550                     zbc->stage = ZBUFFds_flush;
3551                     /* ZBUFFds_flush follows */
3552                 }
3553             }
3554 	    /* fall-through */
3555         case ZBUFFds_flush:
3556             {
3557                 size_t toFlushSize = zbc->outEnd - zbc->outStart;
3558                 size_t flushedSize = ZBUFF_limitCopy(op, oend-op, zbc->outBuff + zbc->outStart, toFlushSize);
3559                 op += flushedSize;
3560                 zbc->outStart += flushedSize;
3561                 if (flushedSize == toFlushSize)
3562                 {
3563                     zbc->stage = ZBUFFds_read;
3564                     if (zbc->outStart + BLOCKSIZE > zbc->outBuffSize)
3565                         zbc->outStart = zbc->outEnd = 0;
3566                     break;
3567                 }
3568                 /* cannot flush everything */
3569                 notDone = 0;
3570                 break;
3571             }
3572         default: return ERROR(GENERIC);   /* impossible */
3573         }
3574     }
3575 
3576     *srcSizePtr = ip-istart;
3577     *maxDstSizePtr = op-ostart;
3578 
3579     {
3580         size_t nextSrcSizeHint = ZSTD_nextSrcSizeToDecompress(zbc->zc);
3581         if (nextSrcSizeHint > 3) nextSrcSizeHint+= 3;   /* get the next block header while at it */
3582         nextSrcSizeHint -= zbc->inPos;   /* already loaded*/
3583         return nextSrcSizeHint;
3584     }
3585 }
3586 
3587 
3588 /* *************************************
3589 *  Tool functions
3590 ***************************************/
3591 unsigned ZBUFFv04_isError(size_t errorCode) { return ERR_isError(errorCode); }
3592 const char* ZBUFFv04_getErrorName(size_t errorCode) { return ERR_getErrorName(errorCode); }
3593 
3594 size_t ZBUFFv04_recommendedDInSize()  { return BLOCKSIZE + 3; }
3595 size_t ZBUFFv04_recommendedDOutSize() { return BLOCKSIZE; }
3596 
3597 
3598 
3599 /*- ========================================================================= -*/
3600 
3601 /* final wrapping stage */
3602 
3603 size_t ZSTDv04_decompressDCtx(ZSTD_DCtx* dctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize)
3604 {
3605     return ZSTD_decompress_usingDict(dctx, dst, maxDstSize, src, srcSize, NULL, 0);
3606 }
3607 
3608 size_t ZSTDv04_decompress(void* dst, size_t maxDstSize, const void* src, size_t srcSize)
3609 {
3610 #if defined(ZSTD_HEAPMODE) && (ZSTD_HEAPMODE==1)
3611     size_t regenSize;
3612     ZSTD_DCtx* dctx = ZSTD_createDCtx();
3613     if (dctx==NULL) return ERROR(memory_allocation);
3614     regenSize = ZSTDv04_decompressDCtx(dctx, dst, maxDstSize, src, srcSize);
3615     ZSTD_freeDCtx(dctx);
3616     return regenSize;
3617 #else
3618     ZSTD_DCtx dctx;
3619     return ZSTDv04_decompressDCtx(&dctx, dst, maxDstSize, src, srcSize);
3620 #endif
3621 }
3622 
3623 size_t ZSTDv04_resetDCtx(ZSTDv04_Dctx* dctx) { return ZSTD_resetDCtx(dctx); }
3624 
3625 size_t ZSTDv04_nextSrcSizeToDecompress(ZSTDv04_Dctx* dctx)
3626 {
3627     return ZSTD_nextSrcSizeToDecompress(dctx);
3628 }
3629 
3630 size_t ZSTDv04_decompressContinue(ZSTDv04_Dctx* dctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize)
3631 {
3632     return ZSTD_decompressContinue(dctx, dst, maxDstSize, src, srcSize);
3633 }
3634 
3635 
3636 
3637 ZBUFFv04_DCtx* ZBUFFv04_createDCtx(void) { return ZBUFF_createDCtx(); }
3638 size_t ZBUFFv04_freeDCtx(ZBUFFv04_DCtx* dctx) { return ZBUFF_freeDCtx(dctx); }
3639 
3640 size_t ZBUFFv04_decompressInit(ZBUFFv04_DCtx* dctx) { return ZBUFF_decompressInit(dctx); }
3641 size_t ZBUFFv04_decompressWithDictionary(ZBUFFv04_DCtx* dctx, const void* src, size_t srcSize)
3642 { return ZBUFF_decompressWithDictionary(dctx, src, srcSize); }
3643 
3644 size_t ZBUFFv04_decompressContinue(ZBUFFv04_DCtx* dctx, void* dst, size_t* maxDstSizePtr, const void* src, size_t* srcSizePtr)
3645 {
3646     DEBUGLOG(5, "ZBUFFv04_decompressContinue");
3647     return ZBUFF_decompressContinue(dctx, dst, maxDstSizePtr, src, srcSizePtr);
3648 }
3649 
3650 ZSTD_DCtx* ZSTDv04_createDCtx(void) { return ZSTD_createDCtx(); }
3651 size_t ZSTDv04_freeDCtx(ZSTD_DCtx* dctx) { return ZSTD_freeDCtx(dctx); }
3652