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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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