diff options
Diffstat (limited to 'src/liblzf/lzf_c.c')
| -rw-r--r-- | src/liblzf/lzf_c.c | 288 |
1 files changed, 171 insertions, 117 deletions
diff --git a/src/liblzf/lzf_c.c b/src/liblzf/lzf_c.c index b9b9ef9..0b5d816 100644 --- a/src/liblzf/lzf_c.c +++ b/src/liblzf/lzf_c.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 2000-2005 Marc Alexander Lehmann <schmorp@schmorp.de> + * Copyright (c) 2000-2008 Marc Alexander Lehmann <schmorp@schmorp.de> * * Redistribution and use in source and binary forms, with or without modifica- * tion, are permitted provided that the following conditions are met: @@ -11,9 +11,6 @@ * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * - * 3. The name of the author may not be used to endorse or promote products - * derived from this software without specific prior written permission. - * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER- * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO @@ -26,14 +23,15 @@ * OF THE POSSIBILITY OF SUCH DAMAGE. * * Alternatively, the contents of this file may be used under the terms of - * the GNU General Public License version 2 (the "GPL"), in which case the - * provisions of the GPL are applicable instead of the above. If you wish to - * allow the use of your version of this file only under the terms of the - * GPL and not to allow others to use your version of this file under the - * BSD license, indicate your decision by deleting the provisions above and - * replace them with the notice and other provisions required by the GPL. If - * you do not delete the provisions above, a recipient may use your version - * of this file under either the BSD or the GPL. + * the GNU General Public License ("GPL") version 2 or any later version, + * in which case the provisions of the GPL are applicable instead of + * the above. If you wish to allow the use of your version of this file + * only under the terms of the GPL and not to allow others to use your + * version of this file under the BSD license, indicate your decision + * by deleting the provisions above and replace them with the notice + * and other provisions required by the GPL. If you do not delete the + * provisions above, a recipient may use your version of this file under + * either the BSD or the GPL. */ #include "lzfP.h" @@ -49,12 +47,18 @@ #ifndef FRST # define FRST(p) (((p[0]) << 8) | p[1]) # define NEXT(v,p) (((v) << 8) | p[2]) -# define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) +# if ULTRA_FAST +# define IDX(h) ((( h >> (3*8 - HLOG)) - h ) & (HSIZE - 1)) +# elif VERY_FAST +# define IDX(h) ((( h >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) +# else +# define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) +# endif #endif /* * IDX works because it is very similar to a multiplicative hash, e.g. * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1)) - * the latter is also quite fast on newer CPUs, and sligthly better + * the latter is also quite fast on newer CPUs, and compresses similarly. * * the next one is also quite good, albeit slow ;) * (int)(cos(h & 0xffffff) * 1e6) @@ -69,7 +73,18 @@ #define MAX_LIT (1 << 5) #define MAX_OFF (1 << 13) -#define MAX_REF ((1 << 8) + (1 << 3)) +#define MAX_REF ((1 << 8) + (1 << 3)) + +#if __GNUC__ >= 3 +# define expect(expr,value) __builtin_expect ((expr),(value)) +# define inline inline +#else +# define expect(expr,value) (expr) +# define inline static +#endif + +#define expect_false(expr) expect ((expr) != 0, 0) +#define expect_true(expr) expect ((expr) != 0, 1) /* * compressed format @@ -84,7 +99,7 @@ unsigned int lzf_compress (const void *const in_data, unsigned int in_len, void *out_data, unsigned int out_len #if LZF_STATE_ARG - , LZF_STATE *htab + , LZF_STATE htab #endif ) { @@ -98,145 +113,184 @@ lzf_compress (const void *const in_data, unsigned int in_len, u8 *out_end = op + out_len; const u8 *ref; - unsigned int hval = FRST (ip); + /* off requires a type wide enough to hold a general pointer difference. + * ISO C doesn't have that (size_t might not be enough and ptrdiff_t only + * works for differences within a single object). We also assume that no + * no bit pattern traps. Since the only platform that is both non-POSIX + * and fails to support both assumptions is windows 64 bit, we make a + * special workaround for it. + */ +#if defined (WIN32) && defined (_M_X64) + unsigned _int64 off; /* workaround for missing POSIX compliance */ +#else unsigned long off; - int lit = 0; +#endif + unsigned int hval; + int lit; + + if (!in_len || !out_len) + return 0; #if INIT_HTAB -# if USE_MEMCPY - memset (htab, 0, sizeof (htab)); -# else - for (hslot = htab; hslot < htab + HSIZE; hslot++) - *hslot++ = ip; + memset (htab, 0, sizeof (htab)); +# if 0 + for (hslot = htab; hslot < htab + HSIZE; hslot++) + *hslot++ = ip; # endif #endif - for (;;) + lit = 0; op++; /* start run */ + + hval = FRST (ip); + while (ip < in_end - 2) { - if (ip < in_end - 2) - { - hval = NEXT (hval, ip); - hslot = htab + IDX (hval); - ref = *hslot; *hslot = ip; + hval = NEXT (hval, ip); + hslot = htab + IDX (hval); + ref = *hslot; *hslot = ip; - if (1 -#if INIT_HTAB && !USE_MEMCPY - && ref < ip /* the next test will actually take care of this, but this is faster */ + if (1 +#if INIT_HTAB + && ref < ip /* the next test will actually take care of this, but this is faster */ #endif - && (off = ip - ref - 1) < MAX_OFF - && ip + 4 < in_end - && ref > (u8 *)in_data + && (off = ip - ref - 1) < MAX_OFF + && ip + 4 < in_end + && ref > (u8 *)in_data #if STRICT_ALIGN - && ref[0] == ip[0] - && ref[1] == ip[1] - && ref[2] == ip[2] + && ref[0] == ip[0] + && ref[1] == ip[1] + && ref[2] == ip[2] #else - && *(u16 *)ref == *(u16 *)ip - && ref[2] == ip[2] + && *(u16 *)ref == *(u16 *)ip + && ref[2] == ip[2] #endif - ) + ) + { + /* match found at *ref++ */ + unsigned int len = 2; + unsigned int maxlen = in_end - ip - len; + maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; + + if (expect_false (op + 3 + 1 >= out_end)) /* first a faster conservative test */ + if (op - !lit + 3 + 1 >= out_end) /* second the exact but rare test */ + return 0; + + op [- lit - 1] = lit - 1; /* stop run */ + op -= !lit; /* undo run if length is zero */ + + for (;;) { - /* match found at *ref++ */ - unsigned int len = 2; - unsigned int maxlen = in_end - ip - len; - maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; + if (expect_true (maxlen > 16)) + { + len++; if (ref [len] != ip [len]) break; + len++; if (ref [len] != ip [len]) break; + len++; if (ref [len] != ip [len]) break; + len++; if (ref [len] != ip [len]) break; + + len++; if (ref [len] != ip [len]) break; + len++; if (ref [len] != ip [len]) break; + len++; if (ref [len] != ip [len]) break; + len++; if (ref [len] != ip [len]) break; - if (op + lit + 1 + 3 >= out_end) - return 0; + len++; if (ref [len] != ip [len]) break; + len++; if (ref [len] != ip [len]) break; + len++; if (ref [len] != ip [len]) break; + len++; if (ref [len] != ip [len]) break; + + len++; if (ref [len] != ip [len]) break; + len++; if (ref [len] != ip [len]) break; + len++; if (ref [len] != ip [len]) break; + len++; if (ref [len] != ip [len]) break; + } do len++; while (len < maxlen && ref[len] == ip[len]); - if (lit) - { - *op++ = lit - 1; - lit = -lit; - do - *op++ = ip[lit]; - while (++lit); - } + break; + } - len -= 2; - ip++; + len -= 2; /* len is now #octets - 1 */ + ip++; - if (len < 7) - { - *op++ = (off >> 8) + (len << 5); - } - else - { - *op++ = (off >> 8) + ( 7 << 5); - *op++ = len - 7; - } + if (len < 7) + { + *op++ = (off >> 8) + (len << 5); + } + else + { + *op++ = (off >> 8) + ( 7 << 5); + *op++ = len - 7; + } - *op++ = off; + *op++ = off; + lit = 0; op++; /* start run */ + + ip += len + 1; + + if (expect_false (ip >= in_end - 2)) + break; #if ULTRA_FAST || VERY_FAST - ip += len; -#if VERY_FAST && !ULTRA_FAST - --ip; -#endif - hval = FRST (ip); + --ip; +# if VERY_FAST && !ULTRA_FAST + --ip; +# endif + hval = FRST (ip); - hval = NEXT (hval, ip); - htab[IDX (hval)] = ip; - ip++; + hval = NEXT (hval, ip); + htab[IDX (hval)] = ip; + ip++; + +# if VERY_FAST && !ULTRA_FAST + hval = NEXT (hval, ip); + htab[IDX (hval)] = ip; + ip++; +# endif +#else + ip -= len + 1; -#if VERY_FAST && !ULTRA_FAST + do + { hval = NEXT (hval, ip); htab[IDX (hval)] = ip; ip++; -#endif -#else - do - { - hval = NEXT (hval, ip); - htab[IDX (hval)] = ip; - ip++; - } - while (len--); -#endif - continue; } + while (len--); +#endif } - else if (ip == in_end) - break; - - /* one more literal byte we must copy */ - lit++; - ip++; - - if (lit == MAX_LIT) + else { - if (op + 1 + MAX_LIT >= out_end) + /* one more literal byte we must copy */ + if (expect_false (op >= out_end)) return 0; - *op++ = MAX_LIT - 1; -#if USE_MEMCPY - memcpy (op, ip - MAX_LIT, MAX_LIT); - op += MAX_LIT; - lit = 0; -#else - lit = -lit; - do - *op++ = ip[lit]; - while (++lit); -#endif + lit++; *op++ = *ip++; + + if (expect_false (lit == MAX_LIT)) + { + op [- lit - 1] = lit - 1; /* stop run */ + lit = 0; op++; /* start run */ + } } } - if (lit) + if (op + 3 > out_end) /* at most 3 bytes can be missing here */ + return 0; + + while (ip < in_end) { - if (op + lit + 1 >= out_end) - return 0; - - *op++ = lit - 1; - lit = -lit; - do - *op++ = ip[lit]; - while (++lit); + lit++; *op++ = *ip++; + + if (expect_false (lit == MAX_LIT)) + { + op [- lit - 1] = lit - 1; /* stop run */ + lit = 0; op++; /* start run */ + } } - return op - (u8 *) out_data; + op [- lit - 1] = lit - 1; /* end run */ + op -= !lit; /* undo run if length is zero */ + + return op - (u8 *)out_data; } + |