diff --git a/src/fastlz.c b/src/fastlz.c index b52a799..8272cf2 100644 --- a/src/fastlz.c +++ b/src/fastlz.c @@ -1,9 +1,6 @@ /* - 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) + FastLZ - Byte-aligned LZ77 compression library + Copyright (C) 2005-2020 Ariya Hidayat Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal @@ -22,528 +19,493 @@ 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. - - SPDX-License-Identifier: MIT */ #include "fastlz.h" -#if !defined(FASTLZ__COMPRESSOR) && !defined(FASTLZ_DECOMPRESSOR) - -/* - * Always check for bound when decompressing. - * Generally it is best to leave it defined. - */ -#define FASTLZ_SAFE +#include +#pragma GCC diagnostic push +#pragma GCC diagnostic ignored "-Wimplicit-fallthrough" /* * 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)) +#if defined(__clang__) || (defined(__GNUC__) && (__GNUC__ > 2)) +#define FASTLZ_LIKELY(c) (__builtin_expect(!!(c), 1)) +#define FASTLZ_UNLIKELY(c) (__builtin_expect(!!(c), 0)) #else -#define FASTLZ_EXPECT_CONDITIONAL(c) (c) -#define FASTLZ_UNEXPECT_CONDITIONAL(c) (c) +#define FASTLZ_LIKELY(c) (c) +#define FASTLZ_UNLIKELY(c) (c) #endif /* - * Use inlined functions for supported systems. + * Specialize custom 64-bit implementation for speed improvements. */ -#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 +#if defined(__x86_64__) || defined(_M_X64) || defined(__aarch64__) +#define FLZ_ARCH64 #endif /* - * Prevent accessing more than 8-bit at once, except on x86 architectures. + * Workaround for DJGPP to find uint8_t, uint16_t, etc. */ -#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__) || defined(__amd64) /* 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 +#if defined(__MSDOS__) && defined(__GNUC__) +#include #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); +#if defined(FASTLZ_USE_MEMMOVE) && (FASTLZ_USE_MEMMOVE == 0) -#define MAX_COPY 32 -#define MAX_LEN 264 /* 256 + 8 */ -#define MAX_DISTANCE 8192 +static void fastlz_memmove(uint8_t* dest, const uint8_t* src, uint32_t count) { + do { + *dest++ = *src++; + } while (--count); +} + +static void fastlz_memcpy(uint8_t* dest, const uint8_t* src, uint32_t count) { + return fastlz_memmove(dest, src, count); +} -#if !defined(FASTLZ_STRICT_ALIGN) -#define FASTLZ_READU16(p) *((const flzuint16*)(p)) #else -#define FASTLZ_READU16(p) ((p)[0] | (p)[1]<<8) + +#include + +static void fastlz_memmove(uint8_t* dest, const uint8_t* src, uint32_t count) { + if ((count > 4) && (dest >= src + count)) { + memmove(dest, src, count); + } else { + switch (count) { + default: + do { + *dest++ = *src++; + } while (--count); + break; + case 3: + *dest++ = *src++; + case 2: + *dest++ = *src++; + case 1: + *dest++ = *src++; + case 0: + break; + } + } +} + +static void fastlz_memcpy(uint8_t* dest, const uint8_t* src, uint32_t count) { memcpy(dest, src, count); } + #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); +#if defined(FLZ_ARCH64) - /* else... */ - return fastlz2_compress(input, length, output); +static uint32_t flz_readu32(const void* ptr) { return *(const uint32_t*)ptr; } + +static uint32_t flz_cmp(const uint8_t* p, const uint8_t* q, const uint8_t* r) { + const uint8_t* start = p; + + if (flz_readu32(p) == flz_readu32(q)) { + p += 4; + q += 4; + } + while (q < r) + if (*p++ != *q++) break; + return p - start; } -int fastlz_decompress(const void* input, int length, void* output, int maxout) -{ - /* magic identifier for compression level */ - int level = ((*(const flzuint8*)input) >> 5) + 1; +#endif /* FLZ_ARCH64 */ - if(level == 1) - return fastlz1_decompress(input, length, output, maxout); - if(level == 2) - return fastlz2_decompress(input, length, output, maxout); +#if !defined(FLZ_ARCH64) - /* unknown level, trigger error */ - return 0; +static uint32_t flz_readu32(const void* ptr) { + const uint8_t* p = (const uint8_t*)ptr; + return (p[3] << 24) | (p[2] << 16) | (p[1] << 8) | p[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); +static uint32_t flz_cmp(const uint8_t* p, const uint8_t* q, const uint8_t* r) { + const uint8_t* start = p; + while (q < r) + if (*p++ != *q++) break; + return p - start; +} - return 0; +#endif /* !FLZ_ARCH64 */ + +#define MAX_COPY 32 +#define MAX_LEN 264 /* 256 + 8 */ +#define MAX_L1_DISTANCE 8192 +#define MAX_L2_DISTANCE 8191 +#define MAX_FARDISTANCE (65535 + MAX_L2_DISTANCE - 1) + +#define HASH_LOG 13 +#define HASH_SIZE (1 << HASH_LOG) +#define HASH_MASK (HASH_SIZE - 1) + +static uint16_t flz_hash(uint32_t v) { + uint32_t h = (v * 2654435769LL) >> (32 - HASH_LOG); + return h & HASH_MASK; } -#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; +/* special case of memcpy: at most MAX_COPY bytes */ +static void flz_smallcopy(uint8_t* dest, const uint8_t* src, uint32_t count) { +#if defined(FLZ_ARCH64) + if (count >= 4) { + const uint32_t* p = (const uint32_t*)src; + uint32_t* q = (uint32_t*)dest; + while (count > 4) { + *q++ = *p++; + count -= 4; + dest += 4; + src += 4; } - else - return 0; } +#endif + fastlz_memcpy(dest, src, count); +} - /* initializes hash table */ - for (hslot = htab; hslot < htab + HASH_SIZE; hslot++) - *hslot = ip; +/* special case of memcpy: exactly MAX_COPY bytes */ +static void flz_maxcopy(void* dest, const void* src) { +#if defined(FLZ_ARCH64) + const uint32_t* p = (const uint32_t*)src; + uint32_t* q = (uint32_t*)dest; + *q++ = *p++; + *q++ = *p++; + *q++ = *p++; + *q++ = *p++; + *q++ = *p++; + *q++ = *p++; + *q++ = *p++; + *q++ = *p++; +#else + fastlz_memcpy(dest, src, MAX_COPY); +#endif +} - /* we start with literal copy */ - copy = 2; - *op++ = MAX_COPY-1; - *op++ = *ip++; - *op++ = *ip++; +static uint8_t* flz_literals(uint32_t runs, const uint8_t* src, uint8_t* dest) { + while (runs >= MAX_COPY) { + *dest++ = MAX_COPY - 1; + flz_maxcopy(dest, src); + src += MAX_COPY; + dest += MAX_COPY; + runs -= MAX_COPY; + } + if (runs > 0) { + *dest++ = runs - 1; + flz_smallcopy(dest, src, runs); + dest += runs; + } + return dest; +} - /* 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; */ /* scan-build, never used */ - ref = anchor - 1 + 3; - goto match; +static uint8_t* flz1_match(uint32_t len, uint32_t distance, uint8_t* op) { + --distance; + if (FASTLZ_UNLIKELY(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; } -#endif + if (len < 7) { + *op++ = (len << 5) + (distance >> 8); + *op++ = (distance & 255); + } else { + *op++ = (7 << 5) + (distance >> 8); + *op++ = len - 7; + *op++ = (distance & 255); + } + return op; +} - /* find potential match */ - HASH_FUNCTION(hval,ip); - hslot = htab + hval; - ref = htab[hval]; +#define FASTLZ_BOUND_CHECK(cond) \ + if (FASTLZ_UNLIKELY(!(cond))) return 0; - /* calculate distance to the match */ - distance = anchor - ref; +static int fastlz1_compress(const void* input, int length, void* output) { + const uint8_t* ip = (const uint8_t*)input; + const uint8_t* ip_start = ip; + const uint8_t* ip_bound = ip + length - 4; /* because readU32 */ + const uint8_t* ip_limit = ip + length - 12 - 1; + uint8_t* op = (uint8_t*)output; - /* update hash table */ - *hslot = anchor; + uint32_t htab[HASH_SIZE]; + uint32_t seq, hash; - /* 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; + /* initializes hash table */ + for (hash = 0; hash < HASH_SIZE; ++hash) htab[hash] = 0; -#if FASTLZ_LEVEL==2 - /* far, needs at least 5-byte match */ - if(distance >= MAX_DISTANCE) - { - if(*ip++ != *ref++ || *ip++!= *ref++) - goto literal; - len += 2; + /* we start with literal copy */ + const uint8_t* anchor = ip; + ip += 2; + + /* main loop */ + while (FASTLZ_LIKELY(ip < ip_limit)) { + const uint8_t* ref; + uint32_t distance, cmp; + + /* find potential match */ + do { + seq = flz_readu32(ip) & 0xffffff; + hash = flz_hash(seq); + ref = ip_start + htab[hash]; + htab[hash] = ip - ip_start; + distance = ip - ref; + cmp = FASTLZ_LIKELY(distance < MAX_L1_DISTANCE) ? flz_readu32(ref) & 0xffffff : 0x1000000; + if (FASTLZ_UNLIKELY(ip >= ip_limit)) break; + ++ip; + } while (seq != cmp); + + if (FASTLZ_UNLIKELY(ip >= ip_limit)) break; + --ip; + + if (FASTLZ_LIKELY(ip > anchor)) { + op = flz_literals(ip - anchor, anchor, op); } - match: -#endif + uint32_t len = flz_cmp(ref + 3, ip + 3, ip_bound); + op = flz1_match(len, distance, op); - /* last matched byte */ - ip = anchor + len; + /* update the hash at match boundary */ + ip += len; + seq = flz_readu32(ip); + hash = flz_hash(seq & 0xffffff); + htab[hash] = ip++ - ip_start; + seq >>= 8; + hash = flz_hash(seq); + htab[hash] = ip++ - ip_start; + + anchor = ip; + } - /* distance is biased */ - distance--; + uint32_t copy = (uint8_t*)input + length - anchor; + op = flz_literals(copy, anchor, op); - 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; - } + return op - (uint8_t*)output; +} - /* 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; +static int fastlz1_decompress(const void* input, int length, void* output, int maxout) { + const uint8_t* ip = (const uint8_t*)input; + const uint8_t* ip_limit = ip + length; + const uint8_t* ip_bound = ip_limit - 2; + uint8_t* op = (uint8_t*)output; + uint8_t* op_limit = op + maxout; + uint32_t ctrl = (*ip++) & 31; + + while (1) { + if (ctrl >= 32) { + uint32_t len = (ctrl >> 5) - 1; + uint32_t ofs = (ctrl & 31) << 8; + const uint8_t* ref = op - ofs - 1; + if (len == 7 - 1) { + FASTLZ_BOUND_CHECK(ip <= ip_bound); + len += *ip++; } + FASTLZ_BOUND_CHECK(ip <= ip_bound); + ref -= *ip++; + len += 3; + FASTLZ_BOUND_CHECK(op + len <= op_limit); + FASTLZ_BOUND_CHECK(ref >= (uint8_t*)output); + fastlz_memmove(op, ref, len); + op += len; + } else { + ctrl++; + FASTLZ_BOUND_CHECK(op + ctrl <= op_limit); + FASTLZ_BOUND_CHECK(ip + ctrl <= ip_limit); + fastlz_memcpy(op, ip, ctrl); + ip += ctrl; + op += ctrl; } -#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 (FASTLZ_UNLIKELY(ip > ip_bound)) break; + ctrl = *ip++; + } - if(len < 7) - { + return op - (uint8_t*)output; +} + +static uint8_t* flz2_match(uint32_t len, uint32_t distance, uint8_t* op) { + --distance; + if (distance < MAX_L2_DISTANCE) { + if (len < 7) { *op++ = (len << 5) + (distance >> 8); *op++ = (distance & 255); - } - else - { + } else { *op++ = (7 << 5) + (distance >> 8); - *op++ = len - 7; + for (len -= 7; len >= 255; len -= 255) *op++ = 255; + *op++ = len; *op++ = (distance & 255); } -#endif + } else { + /* far away, but not yet in the another galaxy... */ + if (len < 7) { + distance -= MAX_L2_DISTANCE; + *op++ = (len << 5) + 31; + *op++ = 255; + *op++ = distance >> 8; + *op++ = distance & 255; + } else { + distance -= MAX_L2_DISTANCE; + *op++ = (7 << 5) + 31; + for (len -= 7; len >= 255; len -= 255) *op++ = 255; + *op++ = len; + *op++ = 255; + *op++ = distance >> 8; + *op++ = distance & 255; + } + } + return op; +} - /* 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; +static int fastlz2_compress(const void* input, int length, void* output) { + const uint8_t* ip = (const uint8_t*)input; + const uint8_t* ip_start = ip; + const uint8_t* ip_bound = ip + length - 4; /* because readU32 */ + const uint8_t* ip_limit = ip + length - 12 - 1; + uint8_t* op = (uint8_t*)output; + + uint32_t htab[HASH_SIZE]; + uint32_t seq, hash; + + /* initializes hash table */ + for (hash = 0; hash < HASH_SIZE; ++hash) htab[hash] = 0; + + /* we start with literal copy */ + const uint8_t* anchor = ip; + ip += 2; + + /* main loop */ + while (FASTLZ_LIKELY(ip < ip_limit)) { + const uint8_t* ref; + uint32_t distance, cmp; + + /* find potential match */ + do { + seq = flz_readu32(ip) & 0xffffff; + hash = flz_hash(seq); + ref = ip_start + htab[hash]; + htab[hash] = ip - ip_start; + distance = ip - ref; + cmp = FASTLZ_LIKELY(distance < MAX_FARDISTANCE) ? flz_readu32(ref) & 0xffffff : 0x1000000; + if (FASTLZ_UNLIKELY(ip >= ip_limit)) break; + ++ip; + } while (seq != cmp); + + if (FASTLZ_UNLIKELY(ip >= ip_limit)) break; + + --ip; + + /* far, needs at least 5-byte match */ + if (distance >= MAX_L2_DISTANCE) { + if (ref[3] != ip[3] || ref[4] != ip[4]) { + ++ip; + continue; } - } + } - /* 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 (FASTLZ_LIKELY(ip > anchor)) { + op = flz_literals(ip - anchor, anchor, op); } + + uint32_t len = flz_cmp(ref + 3, ip + 3, ip_bound); + op = flz2_match(len, distance, op); + + /* update the hash at match boundary */ + ip += len; + seq = flz_readu32(ip); + hash = flz_hash(seq & 0xffffff); + htab[hash] = ip++ - ip_start; + seq >>= 8; + hash = flz_hash(seq); + htab[hash] = ip++ - ip_start; + + anchor = ip; } - /* if we have copied something, adjust the copy length */ - if(copy) - *(op-copy-1) = copy-1; - else - op--; + uint32_t copy = (uint8_t*)input + length - anchor; + op = flz_literals(copy, anchor, op); -#if FASTLZ_LEVEL==2 /* marker for fastlz2 */ - *(flzuint8*)output |= (1 << 5); -#endif + *(uint8_t*)output |= (1 << 5); - return op - (flzuint8*)output; + return op - (uint8_t*)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 - { +static int fastlz2_decompress(const void* input, int length, void* output, int maxout) { + const uint8_t* ip = (const uint8_t*)input; + const uint8_t* ip_limit = ip + length; + const uint8_t* ip_bound = ip_limit - 2; + uint8_t* op = (uint8_t*)output; + uint8_t* op_limit = op + maxout; + uint32_t ctrl = (*ip++) & 31; + + while (1) { + if (ctrl >= 32) { + uint32_t len = (ctrl >> 5) - 1; + uint32_t ofs = (ctrl & 31) << 8; + const uint8_t* ref = op - ofs - 1; + + uint8_t code; + if (len == 7 - 1) do { + FASTLZ_BOUND_CHECK(ip <= ip_bound); code = *ip++; len += code; - } while (code==255); + } while (code == 255); + FASTLZ_BOUND_CHECK(ip <= ip_bound); code = *ip++; ref -= code; + len += 3; /* 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 + if (FASTLZ_UNLIKELY(code == 255)) + if (FASTLZ_LIKELY(ofs == (31 << 8))) { + FASTLZ_BOUND_CHECK(ip < ip_bound); + ofs = (*ip++) << 8; + ofs += *ip++; + ref = op - ofs - MAX_L2_DISTANCE - 1; + } -#ifdef FASTLZ_SAFE - if (FASTLZ_UNEXPECT_CONDITIONAL(op + len + 3 > op_limit)) - return 0; + FASTLZ_BOUND_CHECK(op + len <= op_limit); + FASTLZ_BOUND_CHECK(ref >= (uint8_t*)output); + fastlz_memmove(op, ref, len); + op += len; + } else { + ctrl++; + FASTLZ_BOUND_CHECK(op + ctrl <= op_limit); + FASTLZ_BOUND_CHECK(ip + ctrl <= ip_limit); + fastlz_memcpy(op, ip, ctrl); + ip += ctrl; + op += ctrl; + } - if (FASTLZ_UNEXPECT_CONDITIONAL(ref-1 < (flzuint8 *)output)) - return 0; -#endif + if (FASTLZ_UNLIKELY(ip >= ip_limit)) break; + ctrl = *ip++; + } - 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--; - } + return op - (uint8_t*)output; +} - /* 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 +int fastlz_compress(const void* input, int length, void* output) { + /* for short block, choose fastlz1 */ + if (length < 65536) return fastlz1_compress(input, length, output); - *op++ = *ip++; - for(--ctrl; ctrl; ctrl--) - *op++ = *ip++; + /* else... */ + return fastlz2_compress(input, length, output); +} - loop = FASTLZ_EXPECT_CONDITIONAL(ip < ip_limit); - if(loop) - ctrl = *ip++; - } - } - while(FASTLZ_EXPECT_CONDITIONAL(loop)); +int fastlz_decompress(const void* input, int length, void* output, int maxout) { + if (length < 1) return 0; + /* magic identifier for compression level */ + int level = ((*(const uint8_t*)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; +} - return op - (flzuint8*)output; +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; } -#endif /* !defined(FASTLZ_COMPRESSOR) && !defined(FASTLZ_DECOMPRESSOR) */ +#pragma GCC diagnostic pop diff --git a/src/fastlz.h b/src/fastlz.h index 1ce44a3..9172d74 100644 --- a/src/fastlz.h +++ b/src/fastlz.h @@ -1,9 +1,6 @@ /* - 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) + FastLZ - Byte-aligned LZ77 compression library + Copyright (C) 2005-2020 Ariya Hidayat Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal @@ -22,29 +19,20 @@ 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. - - SPDX-License-Identifier: MIT */ #ifndef FASTLZ_H #define FASTLZ_H -#include - -#define flzuint8 uint8_t -#define flzuint16 uint16_t -#define flzuint32 uint32_t - - -#define FASTLZ_VERSION 0x000100 +#define FASTLZ_VERSION 0x000500 -#define FASTLZ_VERSION_MAJOR 0 -#define FASTLZ_VERSION_MINOR 0 -#define FASTLZ_VERSION_REVISION 0 +#define FASTLZ_VERSION_MAJOR 0 +#define FASTLZ_VERSION_MINOR 5 +#define FASTLZ_VERSION_REVISION 0 -#define FASTLZ_VERSION_STRING "0.1.0" +#define FASTLZ_VERSION_STRING "0.5.0" -#if defined (__cplusplus) +#if defined(__cplusplus) extern "C" { #endif @@ -60,9 +48,17 @@ extern "C" { length (input buffer size). The input buffer and the output buffer can not overlap. + + Compression level can be specified in parameter level. At the moment, + only level 1 and level 2 are supported. + Level 1 is the fastest compression and generally useful for short data. + Level 2 is slightly slower but it gives better compression ratio. + + Note that the compressed data, regardless of the level, can always be + decompressed using the function fastlz_decompress below. */ -int fastlz_compress(const void* input, int length, void* output); +int fastlz_compress_level(int level, const void* input, int length, void* output); /** Decompress a block of compressed data and returns the size of the @@ -74,35 +70,27 @@ int fastlz_compress(const void* input, int length, void* output); Decompression is memory safe and guaranteed not to write the output buffer more than what is specified in maxout. + + Note that the decompression will always work, regardless of the + compression level specified in fastlz_compress_level above (when + producing the compressed block). */ int fastlz_decompress(const void* input, int length, void* output, int maxout); /** - Compress a block of data in the input buffer and returns the size of - compressed block. The size of input buffer is specified by length. The - minimum input buffer size is 16. - - The output buffer must be at least 5% larger than the input buffer - and can not be smaller than 66 bytes. - - If the input is not compressible, the return value might be larger than - length (input buffer size). - - The input buffer and the output buffer can not overlap. + DEPRECATED. - Compression level can be specified in parameter level. At the moment, - only level 1 and level 2 are supported. - Level 1 is the fastest compression and generally useful for short data. - Level 2 is slightly slower but it gives better compression ratio. + This is similar to fastlz_compress_level above, but with the level + automatically chosen. - Note that the compressed data, regardless of the level, can always be - decompressed using the function fastlz_decompress above. + This function is deprecated and it will be completely removed in some future + version. */ -int fastlz_compress_level(int level, const void* input, int length, void* output); +int fastlz_compress(const void* input, int length, void* output); -#if defined (__cplusplus) +#if defined(__cplusplus) } #endif diff --git a/src/meson.build b/src/meson.build index 1987fa5..97db785 100644 --- a/src/meson.build +++ b/src/meson.build @@ -1,5 +1,4 @@ libfst_sources = [ - 'fastlz.c', 'fstapi.c', 'lz4.c', ] @@ -14,10 +13,19 @@ libfst_dependencies = [ thread_dep, ] +# fastlz.c intentionally do unaligned writes, which trigger sanitizers +libfastlz = static_library( + 'fastlz', + 'fastlz.c', + c_args: cc.get_supported_arguments('-fno-sanitize=alignment'), + pic: true, +) + libfst = library( 'fst', sources: libfst_sources, dependencies: libfst_dependencies, + link_whole: libfastlz, version: meson.project_version(), install: true, include_directories: config_inc, @@ -37,4 +45,4 @@ pkg.generate( libraries: libfst, description: 'FST reader and writer library', subdirs: 'libfst', -) \ No newline at end of file +)