--- Compress-LZF/lzf_c.c 2007/11/02 12:36:14 1.7 +++ Compress-LZF/lzf_c.c 2007/11/13 21:50:54 1.8 @@ -1,5 +1,5 @@ /* - * Copyright (c) 2000-2005 Marc Alexander Lehmann + * Copyright (c) 2000-2007 Marc Alexander Lehmann * * 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" @@ -49,8 +47,13 @@ #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)) -/*# define IDX(h) ((ip[0] * 121 ^ ip[1] * 33 ^ ip[2] * 1) & (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. @@ -72,13 +75,17 @@ #define MAX_OFF (1 << 13) #define MAX_REF ((1 << 8) + (1 << 3)) -#if (__i386 || __amd64) && __GNUC__ >= 3 -# define lzf_movsb(dst, src, len) \ - asm ("rep movsb" \ - : "=D" (dst), "=S" (src), "=c" (len) \ - : "0" (dst), "1" (src), "2" (len)); +#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 * @@ -106,9 +113,12 @@ u8 *out_end = op + out_len; const u8 *ref; - unsigned int hval = FRST (ip); + unsigned int hval; unsigned long off; - int lit = 0; + int lit; + + if (!in_len || !out_len) + return 0; #if INIT_HTAB memset (htab, 0, sizeof (htab)); @@ -118,138 +128,145 @@ # 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 (1 #if INIT_HTAB && !USE_MEMCPY - && ref < ip /* the next test will actually take care of this, but this is faster */ + && 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; + ) + { + /* match found at *ref++ */ + unsigned int len = 2; + unsigned int maxlen = in_end - ip - len; + maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; - if (op + lit + 1 + 3 >= out_end) - return 0; + op [- lit - 1] = lit - 1; /* stop run */ + op -= !lit; /* undo run if length is zero */ + + if (expect_false (op + 3 + 1 >= out_end)) + return 0; + + for (;;) + { + 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; + + 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; + 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; #if ULTRA_FAST || VERY_FAST - ip += len; + ip += len; #if VERY_FAST && !ULTRA_FAST - --ip; + --ip; #endif - hval = FRST (ip); + 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 + 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; } - } - else if (ip == in_end) - break; - - /* one more literal byte we must copy */ - lit++; - ip++; + while (len--); +#endif - if (lit == MAX_LIT) + lit = 0; op++; /* start run */ + } + 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; + lit++; *op++ = *ip++; -#ifdef lzf_movsb - ip -= lit; - lzf_movsb (op, ip, lit); -#else - lit = -lit; - do - *op++ = ip[lit]; - while (++lit); -#endif + if (expect_false (lit == MAX_LIT)) + { + op [- lit - 1] = lit - 1; /* stop run */ + lit = 0; op++; /* start run */ + } } } - if (lit) - { - if (op + lit + 1 >= out_end) - return 0; + if (op + 2 > out_end) /* at most 2 bytes can be missing here */ + return 0; - *op++ = lit - 1; -#ifdef lzf_movsb - ip -= lit; - lzf_movsb (op, ip, lit); -#else - lit = -lit; - do - *op++ = ip[lit]; - while (++lit); -#endif + while (ip < in_end) + { + lit++; *op++ = *ip++; } - 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; }