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mfbt/lz4.c

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1 /*
2 LZ4 - Fast LZ compression algorithm
3 Copyright (C) 2011-2014, Yann Collet.
4 BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
5
6 Redistribution and use in source and binary forms, with or without
7 modification, are permitted provided that the following conditions are
8 met:
9
10 * Redistributions of source code must retain the above copyright
11 notice, this list of conditions and the following disclaimer.
12 * Redistributions in binary form must reproduce the above
13 copyright notice, this list of conditions and the following disclaimer
14 in the documentation and/or other materials provided with the
15 distribution.
16
17 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21 OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28
29 You can contact the author at :
30 - LZ4 source repository : http://code.google.com/p/lz4/
31 - LZ4 public forum : https://groups.google.com/forum/#!forum/lz4c
32 */
33
34 /**************************************
35 Tuning parameters
36 **************************************/
37 /*
38 * HEAPMODE :
39 * Select how default compression functions will allocate memory for their hash table,
40 * in memory stack (0:default, fastest), or in memory heap (1:requires memory allocation (malloc)).
41 */
42 #define HEAPMODE 0
43
44
45 /**************************************
46 CPU Feature Detection
47 **************************************/
48 /* 32 or 64 bits ? */
49 #if (defined(__x86_64__) || defined(_M_X64) || defined(_WIN64) \
50 || defined(__powerpc64__) || defined(__powerpc64le__) \
51 || defined(__ppc64__) || defined(__ppc64le__) \
52 || defined(__PPC64__) || defined(__PPC64LE__) \
53 || defined(__ia64) || defined(__itanium__) || defined(_M_IA64) ) /* Detects 64 bits mode */
54 # define LZ4_ARCH64 1
55 #else
56 # define LZ4_ARCH64 0
57 #endif
58
59 /*
60 * Little Endian or Big Endian ?
61 * Overwrite the #define below if you know your architecture endianess
62 */
63 #include <stdlib.h> /* Apparently required to detect endianess */
64 #if defined (__GLIBC__)
65 # include <endian.h>
66 # if (__BYTE_ORDER == __BIG_ENDIAN)
67 # define LZ4_BIG_ENDIAN 1
68 # endif
69 #elif (defined(__BIG_ENDIAN__) || defined(__BIG_ENDIAN) || defined(_BIG_ENDIAN)) && !(defined(__LITTLE_ENDIAN__) || defined(__LITTLE_ENDIAN) || defined(_LITTLE_ENDIAN))
70 # define LZ4_BIG_ENDIAN 1
71 #elif defined(__sparc) || defined(__sparc__) \
72 || defined(__powerpc__) || defined(__ppc__) || defined(__PPC__) \
73 || defined(__hpux) || defined(__hppa) \
74 || defined(_MIPSEB) || defined(__s390__)
75 # define LZ4_BIG_ENDIAN 1
76 #else
77 /* Little Endian assumed. PDP Endian and other very rare endian format are unsupported. */
78 #endif
79
80 /*
81 * Unaligned memory access is automatically enabled for "common" CPU, such as x86.
82 * For others CPU, such as ARM, the compiler may be more cautious, inserting unnecessary extra code to ensure aligned access property
83 * If you know your target CPU supports unaligned memory access, you want to force this option manually to improve performance
84 */
85 #if defined(__ARM_FEATURE_UNALIGNED)
86 # define LZ4_FORCE_UNALIGNED_ACCESS 1
87 #endif
88
89 /* Define this parameter if your target system or compiler does not support hardware bit count */
90 #if defined(_MSC_VER) && defined(_WIN32_WCE) /* Visual Studio for Windows CE does not support Hardware bit count */
91 # define LZ4_FORCE_SW_BITCOUNT
92 #endif
93
94 /*
95 * BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE :
96 * This option may provide a small boost to performance for some big endian cpu, although probably modest.
97 * You may set this option to 1 if data will remain within closed environment.
98 * This option is useless on Little_Endian CPU (such as x86)
99 */
100
101 /* #define BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE 1 */
102
103
104 /**************************************
105 Compiler Options
106 **************************************/
107 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */
108 /* "restrict" is a known keyword */
109 #else
110 # define restrict /* Disable restrict */
111 #endif
112
113 #ifdef _MSC_VER /* Visual Studio */
114 # define FORCE_INLINE static __forceinline
115 # include <intrin.h> /* For Visual 2005 */
116 # if LZ4_ARCH64 /* 64-bits */
117 # pragma intrinsic(_BitScanForward64) /* For Visual 2005 */
118 # pragma intrinsic(_BitScanReverse64) /* For Visual 2005 */
119 # else /* 32-bits */
120 # pragma intrinsic(_BitScanForward) /* For Visual 2005 */
121 # pragma intrinsic(_BitScanReverse) /* For Visual 2005 */
122 # endif
123 # pragma warning(disable : 4127) /* disable: C4127: conditional expression is constant */
124 #else
125 # ifdef __GNUC__
126 # define FORCE_INLINE static inline __attribute__((always_inline))
127 # else
128 # define FORCE_INLINE static inline
129 # endif
130 #endif
131
132 #ifdef _MSC_VER /* Visual Studio */
133 # define lz4_bswap16(x) _byteswap_ushort(x)
134 #else
135 # define lz4_bswap16(x) ((unsigned short int) ((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8)))
136 #endif
137
138 #define GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
139
140 #if (GCC_VERSION >= 302) || (__INTEL_COMPILER >= 800) || defined(__clang__)
141 # define expect(expr,value) (__builtin_expect ((expr),(value)) )
142 #else
143 # define expect(expr,value) (expr)
144 #endif
145
146 #define likely(expr) expect((expr) != 0, 1)
147 #define unlikely(expr) expect((expr) != 0, 0)
148
149
150 /**************************************
151 Memory routines
152 **************************************/
153 #include <stdlib.h> /* malloc, calloc, free */
154 #define ALLOCATOR(n,s) calloc(n,s)
155 #define FREEMEM free
156 #include <string.h> /* memset, memcpy */
157 #define MEM_INIT memset
158
159
160 /**************************************
161 Includes
162 **************************************/
163 #include "lz4.h"
164
165
166 /**************************************
167 Basic Types
168 **************************************/
169 #if defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */
170 # include <stdint.h>
171 typedef uint8_t BYTE;
172 typedef uint16_t U16;
173 typedef uint32_t U32;
174 typedef int32_t S32;
175 typedef uint64_t U64;
176 #else
177 typedef unsigned char BYTE;
178 typedef unsigned short U16;
179 typedef unsigned int U32;
180 typedef signed int S32;
181 typedef unsigned long long U64;
182 #endif
183
184 #if defined(__GNUC__) && !defined(LZ4_FORCE_UNALIGNED_ACCESS)
185 # define _PACKED __attribute__ ((packed))
186 #else
187 # define _PACKED
188 #endif
189
190 #if !defined(LZ4_FORCE_UNALIGNED_ACCESS) && !defined(__GNUC__)
191 # if defined(__IBMC__) || defined(__SUNPRO_C) || defined(__SUNPRO_CC)
192 # pragma pack(1)
193 # else
194 # pragma pack(push, 1)
195 # endif
196 #endif
197
198 typedef struct { U16 v; } _PACKED U16_S;
199 typedef struct { U32 v; } _PACKED U32_S;
200 typedef struct { U64 v; } _PACKED U64_S;
201 typedef struct {size_t v;} _PACKED size_t_S;
202
203 #if !defined(LZ4_FORCE_UNALIGNED_ACCESS) && !defined(__GNUC__)
204 # if defined(__SUNPRO_C) || defined(__SUNPRO_CC)
205 # pragma pack(0)
206 # else
207 # pragma pack(pop)
208 # endif
209 #endif
210
211 #define A16(x) (((U16_S *)(x))->v)
212 #define A32(x) (((U32_S *)(x))->v)
213 #define A64(x) (((U64_S *)(x))->v)
214 #define AARCH(x) (((size_t_S *)(x))->v)
215
216
217 /**************************************
218 Constants
219 **************************************/
220 #define LZ4_HASHLOG (LZ4_MEMORY_USAGE-2)
221 #define HASHTABLESIZE (1 << LZ4_MEMORY_USAGE)
222 #define HASH_SIZE_U32 (1 << LZ4_HASHLOG)
223
224 #define MINMATCH 4
225
226 #define COPYLENGTH 8
227 #define LASTLITERALS 5
228 #define MFLIMIT (COPYLENGTH+MINMATCH)
229 static const int LZ4_minLength = (MFLIMIT+1);
230
231 #define KB *(1U<<10)
232 #define MB *(1U<<20)
233 #define GB *(1U<<30)
234
235 #define LZ4_64KLIMIT ((64 KB) + (MFLIMIT-1))
236 #define SKIPSTRENGTH 6 /* Increasing this value will make the compression run slower on incompressible data */
237
238 #define MAXD_LOG 16
239 #define MAX_DISTANCE ((1 << MAXD_LOG) - 1)
240
241 #define ML_BITS 4
242 #define ML_MASK ((1U<<ML_BITS)-1)
243 #define RUN_BITS (8-ML_BITS)
244 #define RUN_MASK ((1U<<RUN_BITS)-1)
245
246
247 /**************************************
248 Structures and local types
249 **************************************/
250 typedef struct {
251 U32 hashTable[HASH_SIZE_U32];
252 U32 currentOffset;
253 U32 initCheck;
254 const BYTE* dictionary;
255 const BYTE* bufferStart;
256 U32 dictSize;
257 } LZ4_stream_t_internal;
258
259 typedef enum { notLimited = 0, limitedOutput = 1 } limitedOutput_directive;
260 typedef enum { byPtr, byU32, byU16 } tableType_t;
261
262 typedef enum { noDict = 0, withPrefix64k, usingExtDict } dict_directive;
263 typedef enum { noDictIssue = 0, dictSmall } dictIssue_directive;
264
265 typedef enum { endOnOutputSize = 0, endOnInputSize = 1 } endCondition_directive;
266 typedef enum { full = 0, partial = 1 } earlyEnd_directive;
267
268
269 /**************************************
270 Architecture-specific macros
271 **************************************/
272 #define STEPSIZE sizeof(size_t)
273 #define LZ4_COPYSTEP(d,s) { AARCH(d) = AARCH(s); d+=STEPSIZE; s+=STEPSIZE; }
274 #define LZ4_COPY8(d,s) { LZ4_COPYSTEP(d,s); if (STEPSIZE<8) LZ4_COPYSTEP(d,s); }
275
276 #if (defined(LZ4_BIG_ENDIAN) && !defined(BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE))
277 # define LZ4_READ_LITTLEENDIAN_16(d,s,p) { U16 v = A16(p); v = lz4_bswap16(v); d = (s) - v; }
278 # define LZ4_WRITE_LITTLEENDIAN_16(p,i) { U16 v = (U16)(i); v = lz4_bswap16(v); A16(p) = v; p+=2; }
279 #else /* Little Endian */
280 # define LZ4_READ_LITTLEENDIAN_16(d,s,p) { d = (s) - A16(p); }
281 # define LZ4_WRITE_LITTLEENDIAN_16(p,v) { A16(p) = v; p+=2; }
282 #endif
283
284
285 /**************************************
286 Macros
287 **************************************/
288 #define LZ4_STATIC_ASSERT(c) { enum { LZ4_static_assert = 1/(!!(c)) }; } /* use only *after* variable declarations */
289 #if LZ4_ARCH64 || !defined(__GNUC__)
290 # define LZ4_WILDCOPY(d,s,e) { do { LZ4_COPY8(d,s) } while (d<e); } /* at the end, d>=e; */
291 #else
292 # define LZ4_WILDCOPY(d,s,e) { if (likely(e-d <= 8)) LZ4_COPY8(d,s) else do { LZ4_COPY8(d,s) } while (d<e); }
293 #endif
294
295
296 /****************************
297 Private local functions
298 ****************************/
299 #if LZ4_ARCH64
300
301 int LZ4_NbCommonBytes (register U64 val)
302 {
303 # if defined(LZ4_BIG_ENDIAN)
304 # if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
305 unsigned long r = 0;
306 _BitScanReverse64( &r, val );
307 return (int)(r>>3);
308 # elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
309 return (__builtin_clzll(val) >> 3);
310 # else
311 int r;
312 if (!(val>>32)) { r=4; } else { r=0; val>>=32; }
313 if (!(val>>16)) { r+=2; val>>=8; } else { val>>=24; }
314 r += (!val);
315 return r;
316 # endif
317 # else
318 # if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
319 unsigned long r = 0;
320 _BitScanForward64( &r, val );
321 return (int)(r>>3);
322 # elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
323 return (__builtin_ctzll(val) >> 3);
324 # else
325 static const int DeBruijnBytePos[64] = { 0, 0, 0, 0, 0, 1, 1, 2, 0, 3, 1, 3, 1, 4, 2, 7, 0, 2, 3, 6, 1, 5, 3, 5, 1, 3, 4, 4, 2, 5, 6, 7, 7, 0, 1, 2, 3, 3, 4, 6, 2, 6, 5, 5, 3, 4, 5, 6, 7, 1, 2, 4, 6, 4, 4, 5, 7, 2, 6, 5, 7, 6, 7, 7 };
326 return DeBruijnBytePos[((U64)((val & -(long long)val) * 0x0218A392CDABBD3FULL)) >> 58];
327 # endif
328 # endif
329 }
330
331 #else
332
333 int LZ4_NbCommonBytes (register U32 val)
334 {
335 # if defined(LZ4_BIG_ENDIAN)
336 # if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
337 unsigned long r = 0;
338 _BitScanReverse( &r, val );
339 return (int)(r>>3);
340 # elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
341 return (__builtin_clz(val) >> 3);
342 # else
343 int r;
344 if (!(val>>16)) { r=2; val>>=8; } else { r=0; val>>=24; }
345 r += (!val);
346 return r;
347 # endif
348 # else
349 # if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
350 unsigned long r;
351 _BitScanForward( &r, val );
352 return (int)(r>>3);
353 # elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
354 return (__builtin_ctz(val) >> 3);
355 # else
356 static const int DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0, 3, 2, 2, 1, 3, 2, 0, 1, 3, 3, 1, 2, 2, 2, 2, 0, 3, 1, 2, 0, 1, 0, 1, 1 };
357 return DeBruijnBytePos[((U32)((val & -(S32)val) * 0x077CB531U)) >> 27];
358 # endif
359 # endif
360 }
361
362 #endif
363
364
365 /********************************
366 Compression functions
367 ********************************/
368 int LZ4_compressBound(int isize) { return LZ4_COMPRESSBOUND(isize); }
369
370 static int LZ4_hashSequence(U32 sequence, tableType_t tableType)
371 {
372 if (tableType == byU16)
373 return (((sequence) * 2654435761U) >> ((MINMATCH*8)-(LZ4_HASHLOG+1)));
374 else
375 return (((sequence) * 2654435761U) >> ((MINMATCH*8)-LZ4_HASHLOG));
376 }
377
378 static int LZ4_hashPosition(const BYTE* p, tableType_t tableType) { return LZ4_hashSequence(A32(p), tableType); }
379
380 static void LZ4_putPositionOnHash(const BYTE* p, U32 h, void* tableBase, tableType_t tableType, const BYTE* srcBase)
381 {
382 switch (tableType)
383 {
384 case byPtr: { const BYTE** hashTable = (const BYTE**) tableBase; hashTable[h] = p; break; }
385 case byU32: { U32* hashTable = (U32*) tableBase; hashTable[h] = (U32)(p-srcBase); break; }
386 case byU16: { U16* hashTable = (U16*) tableBase; hashTable[h] = (U16)(p-srcBase); break; }
387 }
388 }
389
390 static void LZ4_putPosition(const BYTE* p, void* tableBase, tableType_t tableType, const BYTE* srcBase)
391 {
392 U32 h = LZ4_hashPosition(p, tableType);
393 LZ4_putPositionOnHash(p, h, tableBase, tableType, srcBase);
394 }
395
396 static const BYTE* LZ4_getPositionOnHash(U32 h, void* tableBase, tableType_t tableType, const BYTE* srcBase)
397 {
398 if (tableType == byPtr) { const BYTE** hashTable = (const BYTE**) tableBase; return hashTable[h]; }
399 if (tableType == byU32) { U32* hashTable = (U32*) tableBase; return hashTable[h] + srcBase; }
400 { U16* hashTable = (U16*) tableBase; return hashTable[h] + srcBase; } /* default, to ensure a return */
401 }
402
403 static const BYTE* LZ4_getPosition(const BYTE* p, void* tableBase, tableType_t tableType, const BYTE* srcBase)
404 {
405 U32 h = LZ4_hashPosition(p, tableType);
406 return LZ4_getPositionOnHash(h, tableBase, tableType, srcBase);
407 }
408
409 static unsigned LZ4_count(const BYTE* pIn, const BYTE* pRef, const BYTE* pInLimit)
410 {
411 const BYTE* const pStart = pIn;
412
413 while (likely(pIn<pInLimit-(STEPSIZE-1)))
414 {
415 size_t diff = AARCH(pRef) ^ AARCH(pIn);
416 if (!diff) { pIn+=STEPSIZE; pRef+=STEPSIZE; continue; }
417 pIn += LZ4_NbCommonBytes(diff);
418 return (unsigned)(pIn - pStart);
419 }
420 if (sizeof(void*)==8) if ((pIn<(pInLimit-3)) && (A32(pRef) == A32(pIn))) { pIn+=4; pRef+=4; }
421 if ((pIn<(pInLimit-1)) && (A16(pRef) == A16(pIn))) { pIn+=2; pRef+=2; }
422 if ((pIn<pInLimit) && (*pRef == *pIn)) pIn++;
423
424 return (unsigned)(pIn - pStart);
425 }
426
427
428 static int LZ4_compress_generic(
429 void* ctx,
430 const char* source,
431 char* dest,
432 int inputSize,
433 int maxOutputSize,
434
435 limitedOutput_directive outputLimited,
436 tableType_t tableType,
437 dict_directive dict,
438 dictIssue_directive dictIssue)
439 {
440 LZ4_stream_t_internal* const dictPtr = (LZ4_stream_t_internal*)ctx;
441
442 const BYTE* ip = (const BYTE*) source;
443 const BYTE* base;
444 const BYTE* lowLimit;
445 const BYTE* const lowRefLimit = ip - dictPtr->dictSize;
446 const BYTE* const dictionary = dictPtr->dictionary;
447 const BYTE* const dictEnd = dictionary + dictPtr->dictSize;
448 const size_t dictDelta = dictEnd - (const BYTE*)source;
449 const BYTE* anchor = (const BYTE*) source;
450 const BYTE* const iend = ip + inputSize;
451 const BYTE* const mflimit = iend - MFLIMIT;
452 const BYTE* const matchlimit = iend - LASTLITERALS;
453
454 BYTE* op = (BYTE*) dest;
455 BYTE* const olimit = op + maxOutputSize;
456
457 const int skipStrength = SKIPSTRENGTH;
458 U32 forwardH;
459 size_t refDelta=0;
460
461 /* Init conditions */
462 if ((U32)inputSize > (U32)LZ4_MAX_INPUT_SIZE) return 0; /* Unsupported input size, too large (or negative) */
463 switch(dict)
464 {
465 case noDict:
466 default:
467 base = (const BYTE*)source;
468 lowLimit = (const BYTE*)source;
469 break;
470 case withPrefix64k:
471 base = (const BYTE*)source - dictPtr->currentOffset;
472 lowLimit = (const BYTE*)source - dictPtr->dictSize;
473 break;
474 case usingExtDict:
475 base = (const BYTE*)source - dictPtr->currentOffset;
476 lowLimit = (const BYTE*)source;
477 break;
478 }
479 if ((tableType == byU16) && (inputSize>=(int)LZ4_64KLIMIT)) return 0; /* Size too large (not within 64K limit) */
480 if (inputSize<LZ4_minLength) goto _last_literals; /* Input too small, no compression (all literals) */
481
482 /* First Byte */
483 LZ4_putPosition(ip, ctx, tableType, base);
484 ip++; forwardH = LZ4_hashPosition(ip, tableType);
485
486 /* Main Loop */
487 for ( ; ; )
488 {
489 const BYTE* ref;
490 BYTE* token;
491 {
492 const BYTE* forwardIp = ip;
493 unsigned step=1;
494 unsigned searchMatchNb = (1U << skipStrength);
495
496 /* Find a match */
497 do {
498 U32 h = forwardH;
499 ip = forwardIp;
500 forwardIp += step;
501 step = searchMatchNb++ >> skipStrength;
502 //if (step>8) step=8; // required for valid forwardIp ; slows down uncompressible data a bit
503
504 if (unlikely(forwardIp > mflimit)) goto _last_literals;
505
506 ref = LZ4_getPositionOnHash(h, ctx, tableType, base);
507 if (dict==usingExtDict)
508 {
509 if (ref<(const BYTE*)source)
510 {
511 refDelta = dictDelta;
512 lowLimit = dictionary;
513 }
514 else
515 {
516 refDelta = 0;
517 lowLimit = (const BYTE*)source;
518 }
519 }
520 forwardH = LZ4_hashPosition(forwardIp, tableType);
521 LZ4_putPositionOnHash(ip, h, ctx, tableType, base);
522
523 } while ( ((dictIssue==dictSmall) ? (ref < lowRefLimit) : 0)
524 || ((tableType==byU16) ? 0 : (ref + MAX_DISTANCE < ip))
525 || (A32(ref+refDelta) != A32(ip)) );
526 }
527
528 /* Catch up */
529 while ((ip>anchor) && (ref+refDelta > lowLimit) && (unlikely(ip[-1]==ref[refDelta-1]))) { ip--; ref--; }
530
531 {
532 /* Encode Literal length */
533 unsigned litLength = (unsigned)(ip - anchor);
534 token = op++;
535 if ((outputLimited) && (unlikely(op + litLength + (2 + 1 + LASTLITERALS) + (litLength/255) > olimit)))
536 return 0; /* Check output limit */
537 if (litLength>=RUN_MASK)
538 {
539 int len = (int)litLength-RUN_MASK;
540 *token=(RUN_MASK<<ML_BITS);
541 for(; len >= 255 ; len-=255) *op++ = 255;
542 *op++ = (BYTE)len;
543 }
544 else *token = (BYTE)(litLength<<ML_BITS);
545
546 /* Copy Literals */
547 { BYTE* end = op+litLength; LZ4_WILDCOPY(op,anchor,end); op=end; }
548 }
549
550 _next_match:
551 /* Encode Offset */
552 LZ4_WRITE_LITTLEENDIAN_16(op, (U16)(ip-ref));
553
554 /* Encode MatchLength */
555 {
556 unsigned matchLength;
557
558 if ((dict==usingExtDict) && (lowLimit==dictionary))
559 {
560 const BYTE* limit;
561 ref += refDelta;
562 limit = ip + (dictEnd-ref);
563 if (limit > matchlimit) limit = matchlimit;
564 matchLength = LZ4_count(ip+MINMATCH, ref+MINMATCH, limit);
565 ip += MINMATCH + matchLength;
566 if (ip==limit)
567 {
568 unsigned more = LZ4_count(ip, (const BYTE*)source, matchlimit);
569 matchLength += more;
570 ip += more;
571 }
572 }
573 else
574 {
575 matchLength = LZ4_count(ip+MINMATCH, ref+MINMATCH, matchlimit);
576 ip += MINMATCH + matchLength;
577 }
578
579 if (matchLength>=ML_MASK)
580 {
581 if ((outputLimited) && (unlikely(op + (1 + LASTLITERALS) + (matchLength>>8) > olimit)))
582 return 0; /* Check output limit */
583 *token += ML_MASK;
584 matchLength -= ML_MASK;
585 for (; matchLength >= 510 ; matchLength-=510) { *op++ = 255; *op++ = 255; }
586 if (matchLength >= 255) { matchLength-=255; *op++ = 255; }
587 *op++ = (BYTE)matchLength;
588 }
589 else *token += (BYTE)(matchLength);
590 }
591
592 anchor = ip;
593
594 /* Test end of chunk */
595 if (ip > mflimit) break;
596
597 /* Fill table */
598 LZ4_putPosition(ip-2, ctx, tableType, base);
599
600 /* Test next position */
601 ref = LZ4_getPosition(ip, ctx, tableType, base);
602 if (dict==usingExtDict)
603 {
604 if (ref<(const BYTE*)source)
605 {
606 refDelta = dictDelta;
607 lowLimit = dictionary;
608 }
609 else
610 {
611 refDelta = 0;
612 lowLimit = (const BYTE*)source;
613 }
614 }
615 LZ4_putPosition(ip, ctx, tableType, base);
616 if ( ((dictIssue==dictSmall) ? (ref>=lowRefLimit) : 1)
617 && (ref+MAX_DISTANCE>=ip)
618 && (A32(ref+refDelta)==A32(ip)) )
619 { token=op++; *token=0; goto _next_match; }
620
621 /* Prepare next loop */
622 forwardH = LZ4_hashPosition(++ip, tableType);
623 }
624
625 _last_literals:
626 /* Encode Last Literals */
627 {
628 int lastRun = (int)(iend - anchor);
629 if ((outputLimited) && (((char*)op - dest) + lastRun + 1 + ((lastRun+255-RUN_MASK)/255) > (U32)maxOutputSize))
630 return 0; /* Check output limit */
631 if (lastRun>=(int)RUN_MASK) { *op++=(RUN_MASK<<ML_BITS); lastRun-=RUN_MASK; for(; lastRun >= 255 ; lastRun-=255) *op++ = 255; *op++ = (BYTE) lastRun; }
632 else *op++ = (BYTE)(lastRun<<ML_BITS);
633 memcpy(op, anchor, iend - anchor);
634 op += iend-anchor;
635 }
636
637 /* End */
638 return (int) (((char*)op)-dest);
639 }
640
641
642 int LZ4_compress(const char* source, char* dest, int inputSize)
643 {
644 #if (HEAPMODE)
645 void* ctx = ALLOCATOR(LZ4_STREAMSIZE_U32, 4); /* Aligned on 4-bytes boundaries */
646 #else
647 U32 ctx[LZ4_STREAMSIZE_U32] = {0}; /* Ensure data is aligned on 4-bytes boundaries */
648 #endif
649 int result;
650
651 if (inputSize < (int)LZ4_64KLIMIT)
652 result = LZ4_compress_generic((void*)ctx, source, dest, inputSize, 0, notLimited, byU16, noDict, noDictIssue);
653 else
654 result = LZ4_compress_generic((void*)ctx, source, dest, inputSize, 0, notLimited, (sizeof(void*)==8) ? byU32 : byPtr, noDict, noDictIssue);
655
656 #if (HEAPMODE)
657 FREEMEM(ctx);
658 #endif
659 return result;
660 }
661
662 int LZ4_compress_limitedOutput(const char* source, char* dest, int inputSize, int maxOutputSize)
663 {
664 #if (HEAPMODE)
665 void* ctx = ALLOCATOR(LZ4_STREAMSIZE_U32, 4); /* Aligned on 4-bytes boundaries */
666 #else
667 U32 ctx[LZ4_STREAMSIZE_U32] = {0}; /* Ensure data is aligned on 4-bytes boundaries */
668 #endif
669 int result;
670
671 if (inputSize < (int)LZ4_64KLIMIT)
672 result = LZ4_compress_generic((void*)ctx, source, dest, inputSize, maxOutputSize, limitedOutput, byU16, noDict, noDictIssue);
673 else
674 result = LZ4_compress_generic((void*)ctx, source, dest, inputSize, maxOutputSize, limitedOutput, (sizeof(void*)==8) ? byU32 : byPtr, noDict, noDictIssue);
675
676 #if (HEAPMODE)
677 FREEMEM(ctx);
678 #endif
679 return result;
680 }
681
682
683 /*****************************************
684 Experimental : Streaming functions
685 *****************************************/
686
687 void* LZ4_createStream()
688 {
689 void* lz4s = ALLOCATOR(4, LZ4_STREAMSIZE_U32);
690 MEM_INIT(lz4s, 0, LZ4_STREAMSIZE);
691 return lz4s;
692 }
693
694 int LZ4_free (void* LZ4_stream)
695 {
696 FREEMEM(LZ4_stream);
697 return (0);
698 }
699
700
701 int LZ4_loadDict (void* LZ4_dict, const char* dictionary, int dictSize)
702 {
703 LZ4_stream_t_internal* dict = (LZ4_stream_t_internal*) LZ4_dict;
704 const BYTE* p = (const BYTE*)dictionary;
705 const BYTE* const dictEnd = p + dictSize;
706 const BYTE* base;
707
708 LZ4_STATIC_ASSERT(LZ4_STREAMSIZE >= sizeof(LZ4_stream_t_internal)); /* A compilation error here means LZ4_STREAMSIZE is not large enough */
709 if (dict->initCheck) MEM_INIT(dict, 0, sizeof(LZ4_stream_t_internal)); /* Uninitialized structure detected */
710
711 if (dictSize < MINMATCH)
712 {
713 dict->dictionary = NULL;
714 dict->dictSize = 0;
715 return 1;
716 }
717
718 if (p <= dictEnd - 64 KB) p = dictEnd - 64 KB;
719 base = p - dict->currentOffset;
720 dict->dictionary = p;
721 dict->dictSize = (U32)(dictEnd - p);
722 dict->currentOffset += dict->dictSize;
723
724 while (p <= dictEnd-MINMATCH)
725 {
726 LZ4_putPosition(p, dict, byU32, base);
727 p+=3;
728 }
729
730 return 1;
731 }
732
733
734 void LZ4_renormDictT(LZ4_stream_t_internal* LZ4_dict, const BYTE* src)
735 {
736 if ((LZ4_dict->currentOffset > 0x80000000) ||
737 ((size_t)LZ4_dict->currentOffset > (size_t)src)) /* address space overflow */
738 {
739 /* rescale hash table */
740 U32 delta = LZ4_dict->currentOffset - 64 KB;
741 const BYTE* dictEnd = LZ4_dict->dictionary + LZ4_dict->dictSize;
742 int i;
743 for (i=0; i<HASH_SIZE_U32; i++)
744 {
745 if (LZ4_dict->hashTable[i] < delta) LZ4_dict->hashTable[i]=0;
746 else LZ4_dict->hashTable[i] -= delta;
747 }
748 LZ4_dict->currentOffset = 64 KB;
749 if (LZ4_dict->dictSize > 64 KB) LZ4_dict->dictSize = 64 KB;
750 LZ4_dict->dictionary = dictEnd - LZ4_dict->dictSize;
751 }
752 }
753
754
755 FORCE_INLINE int LZ4_compress_continue_generic (void* LZ4_stream, const char* source, char* dest, int inputSize,
756 int maxOutputSize, limitedOutput_directive limit)
757 {
758 LZ4_stream_t_internal* streamPtr = (LZ4_stream_t_internal*)LZ4_stream;
759 const BYTE* const dictEnd = streamPtr->dictionary + streamPtr->dictSize;
760
761 const BYTE* smallest = (const BYTE*) source;
762 if (streamPtr->initCheck) return 0; /* Uninitialized structure detected */
763 if ((streamPtr->dictSize>0) && (smallest>dictEnd)) smallest = dictEnd;
764 LZ4_renormDictT(streamPtr, smallest);
765
766 /* Check overlapping input/dictionary space */
767 {
768 const BYTE* sourceEnd = (const BYTE*) source + inputSize;
769 if ((sourceEnd > streamPtr->dictionary) && (sourceEnd < dictEnd))
770 {
771 streamPtr->dictSize = (U32)(dictEnd - sourceEnd);
772 if (streamPtr->dictSize > 64 KB) streamPtr->dictSize = 64 KB;
773 if (streamPtr->dictSize < 4) streamPtr->dictSize = 0;
774 streamPtr->dictionary = dictEnd - streamPtr->dictSize;
775 }
776 }
777
778 /* prefix mode : source data follows dictionary */
779 if (dictEnd == (const BYTE*)source)
780 {
781 int result;
782 if ((streamPtr->dictSize < 64 KB) && (streamPtr->dictSize < streamPtr->currentOffset))
783 result = LZ4_compress_generic(LZ4_stream, source, dest, inputSize, maxOutputSize, limit, byU32, withPrefix64k, dictSmall);
784 else
785 result = LZ4_compress_generic(LZ4_stream, source, dest, inputSize, maxOutputSize, limit, byU32, withPrefix64k, noDictIssue);
786 streamPtr->dictSize += (U32)inputSize;
787 streamPtr->currentOffset += (U32)inputSize;
788 return result;
789 }
790
791 /* external dictionary mode */
792 {
793 int result;
794 if ((streamPtr->dictSize < 64 KB) && (streamPtr->dictSize < streamPtr->currentOffset))
795 result = LZ4_compress_generic(LZ4_stream, source, dest, inputSize, maxOutputSize, limit, byU32, usingExtDict, dictSmall);
796 else
797 result = LZ4_compress_generic(LZ4_stream, source, dest, inputSize, maxOutputSize, limit, byU32, usingExtDict, noDictIssue);
798 streamPtr->dictionary = (const BYTE*)source;
799 streamPtr->dictSize = (U32)inputSize;
800 streamPtr->currentOffset += (U32)inputSize;
801 return result;
802 }
803 }
804
805
806 int LZ4_compress_continue (void* LZ4_stream, const char* source, char* dest, int inputSize)
807 {
808 return LZ4_compress_continue_generic(LZ4_stream, source, dest, inputSize, 0, notLimited);
809 }
810
811 int LZ4_compress_limitedOutput_continue (void* LZ4_stream, const char* source, char* dest, int inputSize, int maxOutputSize)
812 {
813 return LZ4_compress_continue_generic(LZ4_stream, source, dest, inputSize, maxOutputSize, limitedOutput);
814 }
815
816
817 // Hidden debug function, to force separate dictionary mode
818 int LZ4_compress_forceExtDict (LZ4_stream_t* LZ4_dict, const char* source, char* dest, int inputSize)
819 {
820 LZ4_stream_t_internal* streamPtr = (LZ4_stream_t_internal*)LZ4_dict;
821 int result;
822 const BYTE* const dictEnd = streamPtr->dictionary + streamPtr->dictSize;
823
824 const BYTE* smallest = dictEnd;
825 if (smallest > (const BYTE*) source) smallest = (const BYTE*) source;
826 LZ4_renormDictT((LZ4_stream_t_internal*)LZ4_dict, smallest);
827
828 result = LZ4_compress_generic(LZ4_dict, source, dest, inputSize, 0, notLimited, byU32, usingExtDict, noDictIssue);
829
830 streamPtr->dictionary = (const BYTE*)source;
831 streamPtr->dictSize = (U32)inputSize;
832 streamPtr->currentOffset += (U32)inputSize;
833
834 return result;
835 }
836
837
838 int LZ4_saveDict (void* LZ4_dict, char* safeBuffer, int dictSize)
839 {
840 LZ4_stream_t_internal* dict = (LZ4_stream_t_internal*) LZ4_dict;
841 const BYTE* previousDictEnd = dict->dictionary + dict->dictSize;
842
843 if ((U32)dictSize > 64 KB) dictSize = 64 KB; /* useless to define a dictionary > 64 KB */
844 if ((U32)dictSize > dict->dictSize) dictSize = dict->dictSize;
845
846 memcpy(safeBuffer, previousDictEnd - dictSize, dictSize);
847
848 dict->dictionary = (const BYTE*)safeBuffer;
849 dict->dictSize = (U32)dictSize;
850
851 return 1;
852 }
853
854
855
856 /****************************
857 Decompression functions
858 ****************************/
859 /*
860 * This generic decompression function cover all use cases.
861 * It shall be instanciated several times, using different sets of directives
862 * Note that it is essential this generic function is really inlined,
863 * in order to remove useless branches during compilation optimisation.
864 */
865 FORCE_INLINE int LZ4_decompress_generic(
866 const char* source,
867 char* dest,
868 int inputSize,
869 int outputSize, /* If endOnInput==endOnInputSize, this value is the max size of Output Buffer. */
870
871 int endOnInput, /* endOnOutputSize, endOnInputSize */
872 int partialDecoding, /* full, partial */
873 int targetOutputSize, /* only used if partialDecoding==partial */
874 int dict, /* noDict, withPrefix64k, usingExtDict */
875 const char* dictStart, /* only if dict==usingExtDict */
876 int dictSize /* note : = 0 if noDict */
877 )
878 {
879 /* Local Variables */
880 const BYTE* restrict ip = (const BYTE*) source;
881 const BYTE* ref;
882 const BYTE* const iend = ip + inputSize;
883
884 BYTE* op = (BYTE*) dest;
885 BYTE* const oend = op + outputSize;
886 BYTE* cpy;
887 BYTE* oexit = op + targetOutputSize;
888 const BYTE* const lowLimit = (const BYTE*)dest - dictSize;
889
890 const BYTE* const dictEnd = (const BYTE*)dictStart + dictSize;
891 //#define OLD
892 #ifdef OLD
893 const size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0}; /* static reduces speed for LZ4_decompress_safe() on GCC64 */
894 #else
895 const size_t dec32table[] = {4-0, 4-3, 4-2, 4-3, 4-0, 4-0, 4-0, 4-0}; /* static reduces speed for LZ4_decompress_safe() on GCC64 */
896 #endif
897 static const size_t dec64table[] = {0, 0, 0, (size_t)-1, 0, 1, 2, 3};
898
899 const int checkOffset = (endOnInput) && (dictSize < (int)(64 KB));
900
901
902 /* Special cases */
903 if ((partialDecoding) && (oexit> oend-MFLIMIT)) oexit = oend-MFLIMIT; /* targetOutputSize too high => decode everything */
904 if ((endOnInput) && (unlikely(outputSize==0))) return ((inputSize==1) && (*ip==0)) ? 0 : -1; /* Empty output buffer */
905 if ((!endOnInput) && (unlikely(outputSize==0))) return (*ip==0?1:-1);
906
907
908 /* Main Loop */
909 while (1)
910 {
911 unsigned token;
912 size_t length;
913
914 /* get runlength */
915 token = *ip++;
916 if ((length=(token>>ML_BITS)) == RUN_MASK)
917 {
918 unsigned s;
919 do
920 {
921 s = *ip++;
922 length += s;
923 }
924 while (likely((endOnInput)?ip<iend-RUN_MASK:1) && (s==255));
925 //if ((sizeof(void*)==4) && unlikely(length>LZ4_MAX_INPUT_SIZE)) goto _output_error; /* overflow detection */
926 if ((sizeof(void*)==4) && unlikely((size_t)(op+length)<(size_t)(op))) goto _output_error; /* quickfix issue 134 */
927 if ((endOnInput) && (sizeof(void*)==4) && unlikely((size_t)(ip+length)<(size_t)(ip))) goto _output_error; /* quickfix issue 134 */
928 }
929
930 /* copy literals */
931 cpy = op+length;
932 if (((endOnInput) && ((cpy>(partialDecoding?oexit:oend-MFLIMIT)) || (ip+length>iend-(2+1+LASTLITERALS))) )
933 || ((!endOnInput) && (cpy>oend-COPYLENGTH)))
934 {
935 if (partialDecoding)
936 {
937 if (cpy > oend) goto _output_error; /* Error : write attempt beyond end of output buffer */
938 if ((endOnInput) && (ip+length > iend)) goto _output_error; /* Error : read attempt beyond end of input buffer */
939 }
940 else
941 {
942 if ((!endOnInput) && (cpy != oend)) goto _output_error; /* Error : block decoding must stop exactly there */
943 if ((endOnInput) && ((ip+length != iend) || (cpy > oend))) goto _output_error; /* Error : input must be consumed */
944 }
945 memcpy(op, ip, length);
946 ip += length;
947 op += length;
948 break; /* Necessarily EOF, due to parsing restrictions */
949 }
950 LZ4_WILDCOPY(op, ip, cpy); ip -= (op-cpy); op = cpy;
951
952 /* get offset */
953 LZ4_READ_LITTLEENDIAN_16(ref,cpy,ip); ip+=2;
954 if ((checkOffset) && (unlikely(ref < lowLimit))) goto _output_error; /* Error : offset outside destination buffer */
955
956 /* get matchlength */
957 if ((length=(token&ML_MASK)) == ML_MASK)
958 {
959 unsigned s;
960 do
961 {
962 if ((endOnInput) && (ip > iend-LASTLITERALS)) goto _output_error;
963 s = *ip++;
964 length += s;
965 } while (s==255);
966 //if ((sizeof(void*)==4) && unlikely(length>LZ4_MAX_INPUT_SIZE)) goto _output_error; /* overflow detection */
967 if ((sizeof(void*)==4) && unlikely((size_t)(op+length)<(size_t)op)) goto _output_error; /* quickfix issue 134 */
968 }
969
970 /* check external dictionary */
971 if ((dict==usingExtDict) && (ref < (BYTE* const)dest))
972 {
973 if (unlikely(op+length+MINMATCH > oend-LASTLITERALS)) goto _output_error;
974
975 if (length+MINMATCH <= (size_t)(dest-(char*)ref))
976 {
977 ref = dictEnd - (dest-(char*)ref);
978 memcpy(op, ref, length+MINMATCH);
979 op += length+MINMATCH;
980 }
981 else
982 {
983 size_t copySize = (size_t)(dest-(char*)ref);
984 memcpy(op, dictEnd - copySize, copySize);
985 op += copySize;
986 copySize = length+MINMATCH - copySize;
987 if (copySize > (size_t)((char*)op-dest)) /* overlap */
988 {
989 BYTE* const cpy = op + copySize;
990 const BYTE* ref = (BYTE*)dest;
991 while (op < cpy) *op++ = *ref++;
992 }
993 else
994 {
995 memcpy(op, dest, copySize);
996 op += copySize;
997 }
998 }
999 continue;
1000 }
1001
1002 /* copy repeated sequence */
1003 if (unlikely((op-ref)<(int)STEPSIZE))
1004 {
1005 const size_t dec64 = dec64table[(sizeof(void*)==4) ? 0 : op-ref];
1006 op[0] = ref[0];
1007 op[1] = ref[1];
1008 op[2] = ref[2];
1009 op[3] = ref[3];
1010 #ifdef OLD
1011 op += 4, ref += 4; ref -= dec32table[op-ref];
1012 A32(op) = A32(ref);
1013 op += STEPSIZE-4; ref -= dec64;
1014 #else
1015 ref += dec32table[op-ref];
1016 A32(op+4) = A32(ref);
1017 op += STEPSIZE; ref -= dec64;
1018 #endif
1019 } else { LZ4_COPYSTEP(op,ref); }
1020 cpy = op + length - (STEPSIZE-4);
1021
1022 if (unlikely(cpy>oend-COPYLENGTH-(STEPSIZE-4)))
1023 {
1024 if (cpy > oend-LASTLITERALS) goto _output_error; /* Error : last 5 bytes must be literals */
1025 if (op<oend-COPYLENGTH) LZ4_WILDCOPY(op, ref, (oend-COPYLENGTH));
1026 while(op<cpy) *op++=*ref++;
1027 op=cpy;
1028 continue;
1029 }
1030 LZ4_WILDCOPY(op, ref, cpy);
1031 op=cpy; /* correction */
1032 }
1033
1034 /* end of decoding */
1035 if (endOnInput)
1036 return (int) (((char*)op)-dest); /* Nb of output bytes decoded */
1037 else
1038 return (int) (((char*)ip)-source); /* Nb of input bytes read */
1039
1040 /* Overflow error detected */
1041 _output_error:
1042 return (int) (-(((char*)ip)-source))-1;
1043 }
1044
1045
1046 int LZ4_decompress_safe(const char* source, char* dest, int compressedSize, int maxOutputSize)
1047 {
1048 return LZ4_decompress_generic(source, dest, compressedSize, maxOutputSize, endOnInputSize, full, 0, noDict, NULL, 0);
1049 }
1050
1051 int LZ4_decompress_safe_partial(const char* source, char* dest, int compressedSize, int targetOutputSize, int maxOutputSize)
1052 {
1053 return LZ4_decompress_generic(source, dest, compressedSize, maxOutputSize, endOnInputSize, partial, targetOutputSize, noDict, NULL, 0);
1054 }
1055
1056 int LZ4_decompress_fast(const char* source, char* dest, int originalSize)
1057 {
1058 return LZ4_decompress_generic(source, dest, 0, originalSize, endOnOutputSize, full, 0, withPrefix64k, NULL, 0);
1059 }
1060
1061 /* streaming decompression functions */
1062
1063 //#define LZ4_STREAMDECODESIZE_U32 4
1064 //#define LZ4_STREAMDECODESIZE (LZ4_STREAMDECODESIZE_U32 * sizeof(unsigned int))
1065 //typedef struct { unsigned int table[LZ4_STREAMDECODESIZE_U32]; } LZ4_streamDecode_t;
1066 typedef struct
1067 {
1068 const char* dictionary;
1069 int dictSize;
1070 } LZ4_streamDecode_t_internal;
1071
1072 /*
1073 * If you prefer dynamic allocation methods,
1074 * LZ4_createStreamDecode()
1075 * provides a pointer (void*) towards an initialized LZ4_streamDecode_t structure.
1076 */
1077 void* LZ4_createStreamDecode()
1078 {
1079 void* lz4s = ALLOCATOR(sizeof(U32), LZ4_STREAMDECODESIZE_U32);
1080 MEM_INIT(lz4s, 0, LZ4_STREAMDECODESIZE);
1081 return lz4s;
1082 }
1083
1084 /*
1085 * LZ4_setDictDecode
1086 * Use this function to instruct where to find the dictionary
1087 * This function is not necessary if previous data is still available where it was decoded.
1088 * Loading a size of 0 is allowed (same effect as no dictionary).
1089 * Return : 1 if OK, 0 if error
1090 */
1091 int LZ4_setDictDecode (void* LZ4_streamDecode, const char* dictionary, int dictSize)
1092 {
1093 LZ4_streamDecode_t_internal* lz4sd = (LZ4_streamDecode_t_internal*) LZ4_streamDecode;
1094 lz4sd->dictionary = dictionary;
1095 lz4sd->dictSize = dictSize;
1096 return 1;
1097 }
1098
1099 /*
1100 *_continue() :
1101 These decoding functions allow decompression of multiple blocks in "streaming" mode.
1102 Previously decoded blocks must still be available at the memory position where they were decoded.
1103 If it's not possible, save the relevant part of decoded data into a safe buffer,
1104 and indicate where it stands using LZ4_setDictDecode()
1105 */
1106 int LZ4_decompress_safe_continue (void* LZ4_streamDecode, const char* source, char* dest, int compressedSize, int maxOutputSize)
1107 {
1108 LZ4_streamDecode_t_internal* lz4sd = (LZ4_streamDecode_t_internal*) LZ4_streamDecode;
1109 int result;
1110
1111 result = LZ4_decompress_generic(source, dest, compressedSize, maxOutputSize, endOnInputSize, full, 0, usingExtDict, lz4sd->dictionary, lz4sd->dictSize);
1112 if (result <= 0) return result;
1113 if (lz4sd->dictionary + lz4sd->dictSize == dest)
1114 {
1115 lz4sd->dictSize += result;
1116 }
1117 else
1118 {
1119 lz4sd->dictionary = dest;
1120 lz4sd->dictSize = result;
1121 }
1122
1123 return result;
1124 }
1125
1126 int LZ4_decompress_fast_continue (void* LZ4_streamDecode, const char* source, char* dest, int originalSize)
1127 {
1128 LZ4_streamDecode_t_internal* lz4sd = (LZ4_streamDecode_t_internal*) LZ4_streamDecode;
1129 int result;
1130
1131 result = LZ4_decompress_generic(source, dest, 0, originalSize, endOnOutputSize, full, 0, usingExtDict, lz4sd->dictionary, lz4sd->dictSize);
1132 if (result <= 0) return result;
1133 if (lz4sd->dictionary + lz4sd->dictSize == dest)
1134 {
1135 lz4sd->dictSize += result;
1136 }
1137 else
1138 {
1139 lz4sd->dictionary = dest;
1140 lz4sd->dictSize = result;
1141 }
1142
1143 return result;
1144 }
1145
1146
1147 /*
1148 Advanced decoding functions :
1149 *_usingDict() :
1150 These decoding functions work the same as "_continue" ones,
1151 the dictionary must be explicitly provided within parameters
1152 */
1153
1154 int LZ4_decompress_safe_usingDict(const char* source, char* dest, int compressedSize, int maxOutputSize, const char* dictStart, int dictSize)
1155 {
1156 return LZ4_decompress_generic(source, dest, compressedSize, maxOutputSize, endOnInputSize, full, 0, usingExtDict, dictStart, dictSize);
1157 }
1158
1159 int LZ4_decompress_fast_usingDict(const char* source, char* dest, int originalSize, const char* dictStart, int dictSize)
1160 {
1161 return LZ4_decompress_generic(source, dest, 0, originalSize, endOnOutputSize, full, 0, usingExtDict, dictStart, dictSize);
1162 }

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