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- /*
- FastLZ - lightning-fast lossless compression library
- Copyright (C) 2007 Ariya Hidayat (ariya@kde.org)
- Copyright (C) 2006 Ariya Hidayat (ariya@kde.org)
- Copyright (C) 2005 Ariya Hidayat (ariya@kde.org)
- Permission is hereby granted, free of charge, to any person obtaining a copy
- of this software and associated documentation files (the "Software"), to deal
- in the Software without restriction, including without limitation the rights
- to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- copies of the Software, and to permit persons to whom the Software is
- furnished to do so, subject to the following conditions:
- The above copyright notice and this permission notice shall be included in
- all copies or substantial portions of the Software.
- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- THE SOFTWARE.
- */
- #if !defined(FASTLZ__COMPRESSOR) && !defined(FASTLZ_DECOMPRESSOR)
- /*
- * Always check for bound when decompressing.
- * Generally it is best to leave it defined.
- */
- #define FASTLZ_SAFE
- /*
- * Give hints to the compiler for branch prediction optimization.
- */
- #if defined(__GNUC__) && (__GNUC__ > 2)
- #define FASTLZ_EXPECT_CONDITIONAL(c) (__builtin_expect((c), 1))
- #define FASTLZ_UNEXPECT_CONDITIONAL(c) (__builtin_expect((c), 0))
- #else
- #define FASTLZ_EXPECT_CONDITIONAL(c) (c)
- #define FASTLZ_UNEXPECT_CONDITIONAL(c) (c)
- #endif
- /*
- * Use inlined functions for supported systems.
- */
- #if defined(__GNUC__) || defined(__DMC__) || defined(__POCC__) || defined(__WATCOMC__) || defined(__SUNPRO_C)
- #define FASTLZ_INLINE inline
- #elif defined(__BORLANDC__) || defined(_MSC_VER) || defined(__LCC__)
- #define FASTLZ_INLINE __inline
- #else
- #define FASTLZ_INLINE
- #endif
- /*
- * Prevent accessing more than 8-bit at once, except on x86 architectures.
- */
- #if !defined(FASTLZ_STRICT_ALIGN)
- #define FASTLZ_STRICT_ALIGN
- #if defined(__i386__) || defined(__386) /* GNU C, Sun Studio */
- #undef FASTLZ_STRICT_ALIGN
- #elif defined(__i486__) || defined(__i586__) || defined(__i686__) /* GNU C */
- #undef FASTLZ_STRICT_ALIGN
- #elif defined(_M_IX86) /* Intel, MSVC */
- #undef FASTLZ_STRICT_ALIGN
- #elif defined(__386)
- #undef FASTLZ_STRICT_ALIGN
- #elif defined(_X86_) /* MinGW */
- #undef FASTLZ_STRICT_ALIGN
- #elif defined(__I86__) /* Digital Mars */
- #undef FASTLZ_STRICT_ALIGN
- #endif
- #endif
- /*
- * FIXME: use preprocessor magic to set this on different platforms!
- */
- typedef unsigned char flzuint8;
- typedef unsigned short flzuint16;
- typedef unsigned int flzuint32;
- /* Disable "conversion from A to B, possible loss of data" warning when using MSVC */
- #if defined(_MSC_VER)
- #pragma warning(disable: 4244)
- #endif
- /* prototypes */
- int fastlz_compress(const void* input, int length, void* output);
- int fastlz_compress_level(int level, const void* input, int length, void* output);
- int fastlz_decompress(const void* input, int length, void* output, int maxout);
- #define MAX_COPY 32
- #define MAX_LEN 264 /* 256 + 8 */
- #define MAX_DISTANCE 8192
- #if !defined(FASTLZ_STRICT_ALIGN)
- #define FASTLZ_READU16(p) *((const flzuint16*)(p))
- #else
- #define FASTLZ_READU16(p) ((p)[0] | (p)[1]<<8)
- #endif
- #define HASH_LOG 13
- #define HASH_SIZE (1<< HASH_LOG)
- #define HASH_MASK (HASH_SIZE-1)
- #define HASH_FUNCTION(v,p) { v = FASTLZ_READU16(p); v ^= FASTLZ_READU16(p+1)^(v>>(16-HASH_LOG));v &= HASH_MASK; }
- #undef FASTLZ_LEVEL
- #define FASTLZ_LEVEL 1
- #undef FASTLZ_COMPRESSOR
- #undef FASTLZ_DECOMPRESSOR
- #define FASTLZ_COMPRESSOR fastlz1_compress
- #define FASTLZ_DECOMPRESSOR fastlz1_decompress
- static FASTLZ_INLINE int FASTLZ_COMPRESSOR(const void* input, int length, void* output);
- static FASTLZ_INLINE int FASTLZ_DECOMPRESSOR(const void* input, int length, void* output, int maxout);
- #include "fastlz.c"
- #undef FASTLZ_LEVEL
- #define FASTLZ_LEVEL 2
- #undef MAX_DISTANCE
- #define MAX_DISTANCE 8191
- #define MAX_FARDISTANCE (65535+MAX_DISTANCE-1)
- #undef FASTLZ_COMPRESSOR
- #undef FASTLZ_DECOMPRESSOR
- #define FASTLZ_COMPRESSOR fastlz2_compress
- #define FASTLZ_DECOMPRESSOR fastlz2_decompress
- static FASTLZ_INLINE int FASTLZ_COMPRESSOR(const void* input, int length, void* output);
- static FASTLZ_INLINE int FASTLZ_DECOMPRESSOR(const void* input, int length, void* output, int maxout);
- #include "fastlz.c"
- int fastlz_compress(const void* input, int length, void* output)
- {
- /* for short block, choose fastlz1 */
- if(length < 65536)
- return fastlz1_compress(input, length, output);
- /* else... */
- return fastlz2_compress(input, length, output);
- }
- int fastlz_decompress(const void* input, int length, void* output, int maxout)
- {
- /* magic identifier for compression level */
- int level = ((*(const flzuint8*)input) >> 5) + 1;
- if(level == 1)
- return fastlz1_decompress(input, length, output, maxout);
- if(level == 2)
- return fastlz2_decompress(input, length, output, maxout);
- /* unknown level, trigger error */
- return 0;
- }
- int fastlz_compress_level(int level, const void* input, int length, void* output)
- {
- if(level == 1)
- return fastlz1_compress(input, length, output);
- if(level == 2)
- return fastlz2_compress(input, length, output);
- return 0;
- }
- #else /* !defined(FASTLZ_COMPRESSOR) && !defined(FASTLZ_DECOMPRESSOR) */
- static FASTLZ_INLINE int FASTLZ_COMPRESSOR(const void* input, int length, void* output)
- {
- const flzuint8* ip = (const flzuint8*) input;
- const flzuint8* ip_bound = ip + length - 2;
- const flzuint8* ip_limit = ip + length - 12;
- flzuint8* op = (flzuint8*) output;
- const flzuint8* htab[HASH_SIZE];
- const flzuint8** hslot;
- flzuint32 hval;
- flzuint32 copy;
- /* sanity check */
- if(FASTLZ_UNEXPECT_CONDITIONAL(length < 4))
- {
- if(length)
- {
- /* create literal copy only */
- *op++ = length-1;
- ip_bound++;
- while(ip <= ip_bound)
- *op++ = *ip++;
- return length+1;
- }
- else
- return 0;
- }
- /* initializes hash table */
- for (hslot = htab; hslot < htab + HASH_SIZE; hslot++)
- *hslot = ip;
- /* we start with literal copy */
- copy = 2;
- *op++ = MAX_COPY-1;
- *op++ = *ip++;
- *op++ = *ip++;
- /* main loop */
- while(FASTLZ_EXPECT_CONDITIONAL(ip < ip_limit))
- {
- const flzuint8* ref;
- flzuint32 distance;
- /* minimum match length */
- flzuint32 len = 3;
- /* comparison starting-point */
- const flzuint8* anchor = ip;
- /* check for a run */
- #if FASTLZ_LEVEL==2
- if(ip[0] == ip[-1] && FASTLZ_READU16(ip-1)==FASTLZ_READU16(ip+1))
- {
- distance = 1;
- ip += 3;
- ref = anchor - 1 + 3;
- goto match;
- }
- #endif
- /* find potential match */
- HASH_FUNCTION(hval,ip);
- hslot = htab + hval;
- ref = htab[hval];
- /* calculate distance to the match */
- distance = anchor - ref;
- /* update hash table */
- *hslot = anchor;
- /* is this a match? check the first 3 bytes */
- if(distance==0 ||
- #if FASTLZ_LEVEL==1
- (distance >= MAX_DISTANCE) ||
- #else
- (distance >= MAX_FARDISTANCE) ||
- #endif
- *ref++ != *ip++ || *ref++!=*ip++ || *ref++!=*ip++)
- goto literal;
- #if FASTLZ_LEVEL==2
- /* far, needs at least 5-byte match */
- if(distance >= MAX_DISTANCE)
- {
- if(*ip++ != *ref++ || *ip++!= *ref++)
- goto literal;
- len += 2;
- }
-
- match:
- #endif
- /* last matched byte */
- ip = anchor + len;
- /* distance is biased */
- distance--;
- if(!distance)
- {
- /* zero distance means a run */
- flzuint8 x = ip[-1];
- while(ip < ip_bound)
- if(*ref++ != x) break; else ip++;
- }
- else
- for(;;)
- {
- /* safe because the outer check against ip limit */
- if(*ref++ != *ip++) break;
- if(*ref++ != *ip++) break;
- if(*ref++ != *ip++) break;
- if(*ref++ != *ip++) break;
- if(*ref++ != *ip++) break;
- if(*ref++ != *ip++) break;
- if(*ref++ != *ip++) break;
- if(*ref++ != *ip++) break;
- while(ip < ip_bound)
- if(*ref++ != *ip++) break;
- break;
- }
- /* if we have copied something, adjust the copy count */
- if(copy)
- /* copy is biased, '0' means 1 byte copy */
- *(op-copy-1) = copy-1;
- else
- /* back, to overwrite the copy count */
- op--;
- /* reset literal counter */
- copy = 0;
- /* length is biased, '1' means a match of 3 bytes */
- ip -= 3;
- len = ip - anchor;
- /* encode the match */
- #if FASTLZ_LEVEL==2
- if(distance < MAX_DISTANCE)
- {
- if(len < 7)
- {
- *op++ = (len << 5) + (distance >> 8);
- *op++ = (distance & 255);
- }
- else
- {
- *op++ = (7 << 5) + (distance >> 8);
- for(len-=7; len >= 255; len-= 255)
- *op++ = 255;
- *op++ = len;
- *op++ = (distance & 255);
- }
- }
- else
- {
- /* far away, but not yet in the another galaxy... */
- if(len < 7)
- {
- distance -= MAX_DISTANCE;
- *op++ = (len << 5) + 31;
- *op++ = 255;
- *op++ = distance >> 8;
- *op++ = distance & 255;
- }
- else
- {
- distance -= MAX_DISTANCE;
- *op++ = (7 << 5) + 31;
- for(len-=7; len >= 255; len-= 255)
- *op++ = 255;
- *op++ = len;
- *op++ = 255;
- *op++ = distance >> 8;
- *op++ = distance & 255;
- }
- }
- #else
- if(FASTLZ_UNEXPECT_CONDITIONAL(len > MAX_LEN-2))
- while(len > MAX_LEN-2)
- {
- *op++ = (7 << 5) + (distance >> 8);
- *op++ = MAX_LEN - 2 - 7 -2;
- *op++ = (distance & 255);
- len -= MAX_LEN-2;
- }
- if(len < 7)
- {
- *op++ = (len << 5) + (distance >> 8);
- *op++ = (distance & 255);
- }
- else
- {
- *op++ = (7 << 5) + (distance >> 8);
- *op++ = len - 7;
- *op++ = (distance & 255);
- }
- #endif
- /* update the hash at match boundary */
- HASH_FUNCTION(hval,ip);
- htab[hval] = ip++;
- HASH_FUNCTION(hval,ip);
- htab[hval] = ip++;
- /* assuming literal copy */
- *op++ = MAX_COPY-1;
- continue;
- literal:
- *op++ = *anchor++;
- ip = anchor;
- copy++;
- if(FASTLZ_UNEXPECT_CONDITIONAL(copy == MAX_COPY))
- {
- copy = 0;
- *op++ = MAX_COPY-1;
- }
- }
- /* left-over as literal copy */
- ip_bound++;
- while(ip <= ip_bound)
- {
- *op++ = *ip++;
- copy++;
- if(copy == MAX_COPY)
- {
- copy = 0;
- *op++ = MAX_COPY-1;
- }
- }
- /* if we have copied something, adjust the copy length */
- if(copy)
- *(op-copy-1) = copy-1;
- else
- op--;
- #if FASTLZ_LEVEL==2
- /* marker for fastlz2 */
- *(flzuint8*)output |= (1 << 5);
- #endif
- return op - (flzuint8*)output;
- }
- static FASTLZ_INLINE int FASTLZ_DECOMPRESSOR(const void* input, int length, void* output, int maxout)
- {
- const flzuint8* ip = (const flzuint8*) input;
- const flzuint8* ip_limit = ip + length;
- flzuint8* op = (flzuint8*) output;
- flzuint8* op_limit = op + maxout;
- flzuint32 ctrl = (*ip++) & 31;
- int loop = 1;
- do
- {
- const flzuint8* ref = op;
- flzuint32 len = ctrl >> 5;
- flzuint32 ofs = (ctrl & 31) << 8;
- if(ctrl >= 32)
- {
- #if FASTLZ_LEVEL==2
- flzuint8 code;
- #endif
- len--;
- ref -= ofs;
- if (len == 7-1)
- #if FASTLZ_LEVEL==1
- len += *ip++;
- ref -= *ip++;
- #else
- do
- {
- code = *ip++;
- len += code;
- } while (code==255);
- code = *ip++;
- ref -= code;
- /* match from 16-bit distance */
- if(FASTLZ_UNEXPECT_CONDITIONAL(code==255))
- if(FASTLZ_EXPECT_CONDITIONAL(ofs==(31 << 8)))
- {
- ofs = (*ip++) << 8;
- ofs += *ip++;
- ref = op - ofs - MAX_DISTANCE;
- }
- #endif
-
- #ifdef FASTLZ_SAFE
- if (FASTLZ_UNEXPECT_CONDITIONAL(op + len + 3 > op_limit))
- return 0;
- if (FASTLZ_UNEXPECT_CONDITIONAL(ref-1 < (flzuint8 *)output))
- return 0;
- #endif
- if(FASTLZ_EXPECT_CONDITIONAL(ip < ip_limit))
- ctrl = *ip++;
- else
- loop = 0;
- if(ref == op)
- {
- /* optimize copy for a run */
- flzuint8 b = ref[-1];
- *op++ = b;
- *op++ = b;
- *op++ = b;
- for(; len; --len)
- *op++ = b;
- }
- else
- {
- #if !defined(FASTLZ_STRICT_ALIGN)
- const flzuint16* p;
- flzuint16* q;
- #endif
- /* copy from reference */
- ref--;
- *op++ = *ref++;
- *op++ = *ref++;
- *op++ = *ref++;
- #if !defined(FASTLZ_STRICT_ALIGN)
- /* copy a byte, so that now it's word aligned */
- if(len & 1)
- {
- *op++ = *ref++;
- len--;
- }
- /* copy 16-bit at once */
- q = (flzuint16*) op;
- op += len;
- p = (const flzuint16*) ref;
- for(len>>=1; len > 4; len-=4)
- {
- *q++ = *p++;
- *q++ = *p++;
- *q++ = *p++;
- *q++ = *p++;
- }
- for(; len; --len)
- *q++ = *p++;
- #else
- for(; len; --len)
- *op++ = *ref++;
- #endif
- }
- }
- else
- {
- ctrl++;
- #ifdef FASTLZ_SAFE
- if (FASTLZ_UNEXPECT_CONDITIONAL(op + ctrl > op_limit))
- return 0;
- if (FASTLZ_UNEXPECT_CONDITIONAL(ip + ctrl > ip_limit))
- return 0;
- #endif
- *op++ = *ip++;
- for(--ctrl; ctrl; ctrl--)
- *op++ = *ip++;
- loop = FASTLZ_EXPECT_CONDITIONAL(ip < ip_limit);
- if(loop)
- ctrl = *ip++;
- }
- }
- while(FASTLZ_EXPECT_CONDITIONAL(loop));
- return op - (flzuint8*)output;
- }
- #endif /* !defined(FASTLZ_COMPRESSOR) && !defined(FASTLZ_DECOMPRESSOR) */
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