[ViewVC] Diff of: cvs/liblzf/lzf

Comparing liblzf/lzf_c.c (file contents):
Revision 1.6 by pcg, Tue Apr 20 18:11:58 2004 UTC vs.
Revision 1.35 by root, Sat Aug 30 06:43:38 2008 UTC

…		…
1	/*	1	/*
2	* Copyright (c) 2000-2003 Marc Alexander Lehmann <pcg@goof.com>	2	* Copyright (c) 2000-2008 Marc Alexander Lehmann <schmorp@schmorp.de>
3	*	3	*
4	* Redistribution and use in source and binary forms, with or without modifica-	4	* Redistribution and use in source and binary forms, with or without modifica-
5	* tion, are permitted provided that the following conditions are met:	5	* tion, are permitted provided that the following conditions are met:
6	*	6	*
7	* 1. Redistributions of source code must retain the above copyright notice,	7	* 1. Redistributions of source code must retain the above copyright notice,
8	* this list of conditions and the following disclaimer.	8	* this list of conditions and the following disclaimer.
9	*	9	*
10	* 2. Redistributions in binary form must reproduce the above copyright	10	* 2. Redistributions in binary form must reproduce the above copyright
11	* notice, this list of conditions and the following disclaimer in the	11	* notice, this list of conditions and the following disclaimer in the
12	* documentation and/or other materials provided with the distribution.	12	* documentation and/or other materials provided with the distribution.
13	*
14	* 3. The name of the author may not be used to endorse or promote products
15	* derived from this software without specific prior written permission.
16	*	13	*
17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED	14	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
18	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-	15	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
19	* CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO	16	* CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
20	* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-	17	* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
24	* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-	21	* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
25	* ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED	22	* ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
26	* OF THE POSSIBILITY OF SUCH DAMAGE.	23	* OF THE POSSIBILITY OF SUCH DAMAGE.
27	*	24	*
28	* Alternatively, the contents of this file may be used under the terms of	25	* Alternatively, the contents of this file may be used under the terms of
29	* the GNU General Public License version 2 (the "GPL"), in which case the	26	* the GNU General Public License ("GPL") version 2 or any later version,
30	* provisions of the GPL are applicable instead of the above. If you wish to	27	* in which case the provisions of the GPL are applicable instead of
31	* allow the use of your version of this file only under the terms of the	28	* the above. If you wish to allow the use of your version of this file
32	* GPL and not to allow others to use your version of this file under the	29	* only under the terms of the GPL and not to allow others to use your
33	* BSD license, indicate your decision by deleting the provisions above and	30	* version of this file under the BSD license, indicate your decision
34	* replace them with the notice and other provisions required by the GPL. If	31	* by deleting the provisions above and replace them with the notice
35	* you do not delete the provisions above, a recipient may use your version	32	* and other provisions required by the GPL. If you do not delete the
		33	* provisions above, a recipient may use your version of this file under
36	* of this file under either the BSD or the GPL.	34	* either the BSD or the GPL.
37	*/	35	*/
38		36
39	#include "lzfP.h"	37	#include "lzfP.h"
40		38
41	#define HSIZE (1 << (HLOG))	39	#define HSIZE (1 << (HLOG))
…		…
44	* don't play with this unless you benchmark!	42	* don't play with this unless you benchmark!
45	* decompression is not dependent on the hash function	43	* decompression is not dependent on the hash function
46	* the hashing function might seem strange, just believe me	44	* the hashing function might seem strange, just believe me
47	* it works ;)	45	* it works ;)
48	*/	46	*/
		47	#ifndef FRST
49	#define FRST(p) (((p[0]) << 8) + p[1])	48	# define FRST(p) (((p[0]) << 8) \| p[1])
50	#define NEXT(v,p) (((v) << 8) + p[2])	49	# define NEXT(v,p) (((v) << 8) \| p[2])
		50	# if ULTRA_FAST
		51	# define IDX(h) ((( h >> (3*8 - HLOG)) - h ) & (HSIZE - 1))
		52	# elif VERY_FAST
		53	# define IDX(h) ((( h >> (38 - HLOG)) - h5) & (HSIZE - 1))
		54	# else
51	#define IDX(h) ((((h ^ (h << 5)) >> (38 - HLOG)) + h3) & (HSIZE - 1))	55	# define IDX(h) ((((h ^ (h << 5)) >> (38 - HLOG)) - h5) & (HSIZE - 1))
		56	# endif
		57	#endif
52	/*	58	/*
53	* IDX works because it is very similar to a multiplicative hash, e.g.	59	* IDX works because it is very similar to a multiplicative hash, e.g.
54	* (h * 57321 >> (3*8 - HLOG))	60	* ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1))
		61	* the latter is also quite fast on newer CPUs, and compresses similarly.
		62	*
55	* the next one is also quite good, albeit slow ;)	63	* the next one is also quite good, albeit slow ;)
56	* (int)(cos(h & 0xffffff) * 1e6)	64	* (int)(cos(h & 0xffffff) * 1e6)
57	*/	65	*/
58		66
59	#if 0	67	#if 0
60	/* original lzv-like hash function */	68	/* original lzv-like hash function, much worse and thus slower */
61	# define FRST(p) (p[0] << 5) ^ p[1]	69	# define FRST(p) (p[0] << 5) ^ p[1]
62	# define NEXT(v,p) ((v) << 5) ^ p[2]	70	# define NEXT(v,p) ((v) << 5) ^ p[2]
63	# define IDX(h) ((h) & (HSIZE - 1))	71	# define IDX(h) ((h) & (HSIZE - 1))
64	#endif	72	#endif
65		73
66	#define MAX_LIT (1 << 5)	74	#define MAX_LIT (1 << 5)
67	#define MAX_OFF (1 << 13)	75	#define MAX_OFF (1 << 13)
68	#define MAX_REF ((1 << 8) + (1 << 3))	76	#define MAX_REF ((1 << 8) + (1 << 3))
		77
		78	#if __GNUC__ >= 3
		79	# define expect(expr,value) __builtin_expect ((expr),(value))
		80	# define inline inline
		81	#else
		82	# define expect(expr,value) (expr)
		83	# define inline static
		84	#endif
		85
		86	#define expect_false(expr) expect ((expr) != 0, 0)
		87	#define expect_true(expr) expect ((expr) != 0, 1)
69		88
70	/*	89	/*
71	* compressed format	90	* compressed format
72	*	91	*
73	* 000LLLLL <L+1> ; literal	92	* 000LLLLL <L+1> ; literal
74	* LLLOOOOO oooooooo ; backref L	93	* LLLooooo oooooooo ; backref L
75	* 111OOOOO LLLLLLLL oooooooo ; backref L+7	94	* 111ooooo LLLLLLLL oooooooo ; backref L+7
76	*	95	*
77	*/	96	*/
78		97
79	unsigned int	98	unsigned int
80	lzf_compress (const void *const in_data, unsigned int in_len,	99	lzf_compress (const void *const in_data, unsigned int in_len,
81	void *out_data, unsigned int out_len	100	void *out_data, unsigned int out_len
82	#if LZF_STATE_ARG	101	#if LZF_STATE_ARG
83	, LZF_STATE *htab	102	, LZF_STATE htab
84	#endif	103	#endif
85	)	104	)
86	{	105	{
87	#if !LZF_STATE_ARG	106	#if !LZF_STATE_ARG
88	LZF_STATE htab;	107	LZF_STATE htab;
…		…
92	u8 op = (u8 )out_data;	111	u8 op = (u8 )out_data;
93	const u8 *in_end = ip + in_len;	112	const u8 *in_end = ip + in_len;
94	u8 *out_end = op + out_len;	113	u8 *out_end = op + out_len;
95	const u8 *ref;	114	const u8 *ref;
96		115
97	unsigned int hval = FRST (ip);	116	/* off requires a type wide enough to hold a general pointer difference.
		117	* ISO C doesn't have that (size_t might not be enough and ptrdiff_t only
		118	* works for differences within a single object). We also assume that no
		119	* no bit pattern traps. Since the only platform that is both non-POSIX
		120	* and fails to support both assumptions is windows 64 bit, we make a
		121	* special workaround for it.
		122	*/
		123	#if defined (WIN32) && defined (_M_X64)
		124	unsigned _int64 off; /* workaround for missing POSIX compliance */
		125	#else
98	unsigned long off;	126	unsigned long off;
99	int lit = 0;	127	#endif
		128	unsigned int hval;
		129	int lit;
		130
		131	if (!in_len \|\| !out_len)
		132	return 0;
100		133
101	#if INIT_HTAB	134	#if INIT_HTAB
102	# if USE_MEMCPY
103	memset (htab, 0, sizeof (htab));	135	memset (htab, 0, sizeof (htab));
104	# else	136	# if 0
105	for (hslot = htab; hslot < htab + HSIZE; hslot++)	137	for (hslot = htab; hslot < htab + HSIZE; hslot++)
106	*hslot++ = ip;	138	*hslot++ = ip;
107	# endif
108	#endif	139	# endif
		140	#endif
109		141
110	for (;;)	142	lit = 0; op++; /* start run */
		143
		144	hval = FRST (ip);
		145	while (ip < in_end - 2)
111	{	146	{
112	if (ip < in_end - 2)	147	hval = NEXT (hval, ip);
		148	hslot = htab + IDX (hval);
		149	ref = hslot; hslot = ip;
		150
		151	if (1
		152	#if INIT_HTAB
		153	&& ref < ip /* the next test will actually take care of this, but this is faster */
		154	#endif
		155	&& (off = ip - ref - 1) < MAX_OFF
		156	&& ip + 4 < in_end
		157	&& ref > (u8 *)in_data
		158	#if STRICT_ALIGN
		159	&& ref[0] == ip[0]
		160	&& ref[1] == ip[1]
		161	&& ref[2] == ip[2]
		162	#else
		163	&& (u16 )ref == (u16 )ip
		164	&& ref[2] == ip[2]
		165	#endif
		166	)
113	{	167	{
114	hval = NEXT (hval, ip);
115	hslot = htab + IDX (hval);
116	ref = hslot; hslot = ip;
117
118	if (1
119	#if INIT_HTAB && !USE_MEMCPY
120	&& ref < ip /* the next test will actually take care of this, but this is faster */
121	#endif
122	&& (off = ip - ref - 1) < MAX_OFF
123	&& ip + 4 < in_end
124	&& ref > (u8 *)in_data
125	#if STRICT_ALIGN
126	&& ref[0] == ip[0]
127	&& ref[1] == ip[1]
128	&& ref[2] == ip[2]
129	#else
130	&& (u16 )ref == (u16 )ip
131	&& ref[2] == ip[2]
132	#endif
133	)
134	{
135	/* match found at ref++ /	168	/* match found at ref++ /
136	unsigned int len = 2;	169	unsigned int len = 2;
137	unsigned int maxlen = in_end - ip - len;	170	unsigned int maxlen = in_end - ip - len;
138	maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;	171	maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
		172
		173	op [- lit - 1] = lit - 1; /* stop run */
		174	op -= !lit; /* undo run if length is zero */
		175
		176	if (expect_false (op + 3 + 1 >= out_end))
		177	return 0;
		178
		179	for (;;)
		180	{
		181	if (expect_true (maxlen > 16))
		182	{
		183	len++; if (ref [len] != ip [len]) break;
		184	len++; if (ref [len] != ip [len]) break;
		185	len++; if (ref [len] != ip [len]) break;
		186	len++; if (ref [len] != ip [len]) break;
		187
		188	len++; if (ref [len] != ip [len]) break;
		189	len++; if (ref [len] != ip [len]) break;
		190	len++; if (ref [len] != ip [len]) break;
		191	len++; if (ref [len] != ip [len]) break;
		192
		193	len++; if (ref [len] != ip [len]) break;
		194	len++; if (ref [len] != ip [len]) break;
		195	len++; if (ref [len] != ip [len]) break;
		196	len++; if (ref [len] != ip [len]) break;
		197
		198	len++; if (ref [len] != ip [len]) break;
		199	len++; if (ref [len] != ip [len]) break;
		200	len++; if (ref [len] != ip [len]) break;
		201	len++; if (ref [len] != ip [len]) break;
		202	}
139		203
140	do	204	do
141	len++;	205	len++;
142	while (len < maxlen && ref[len] == ip[len]);	206	while (len < maxlen && ref[len] == ip[len]);
143		207
144	if (op + lit + 1 + 3 >= out_end)
145	return 0;
146
147	if (lit)
148	{	208	break;
149	*op++ = lit - 1;
150	lit = -lit;
151	do
152	*op++ = ip[lit];
153	while (++lit);
154	}	209	}
155		210
156	len -= 2;	211	len -= 2; /* len is now #octets - 1 */
157	ip++;	212	ip++;
158		213
159	if (len < 7)	214	if (len < 7)
160	{	215	{
161	*op++ = (off >> 8) + (len << 5);	216	*op++ = (off >> 8) + (len << 5);
162	}	217	}
163	else	218	else
164	{	219	{
165	*op++ = (off >> 8) + ( 7 << 5);	220	*op++ = (off >> 8) + ( 7 << 5);
166	*op++ = len - 7;	221	*op++ = len - 7;
167	}	222	}
168		223
169	*op++ = off;	224	*op++ = off;
		225	lit = 0; op++; /* start run */
170		226
171	#if ULTRA_FAST
172	ip += len;	227	ip += len + 1;
		228
		229	if (expect_false (ip >= in_end - 2))
		230	break;
		231
		232	#if ULTRA_FAST \|\| VERY_FAST
		233	--ip;
		234	# if VERY_FAST && !ULTRA_FAST
		235	--ip;
		236	# endif
173	hval = FRST (ip);	237	hval = FRST (ip);
		238
		239	hval = NEXT (hval, ip);
		240	htab[IDX (hval)] = ip;
		241	ip++;
		242
		243	# if VERY_FAST && !ULTRA_FAST
		244	hval = NEXT (hval, ip);
		245	htab[IDX (hval)] = ip;
		246	ip++;
		247	# endif
		248	#else
		249	ip -= len + 1;
		250
		251	do
		252	{
174	hval = NEXT (hval, ip);	253	hval = NEXT (hval, ip);
175	htab[IDX (hval)] = ip;	254	htab[IDX (hval)] = ip;
176	ip++;	255	ip++;
177	#else
178	do
179	{
180	hval = NEXT (hval, ip);
181	htab[IDX (hval)] = ip;
182	ip++;
183	}	256	}
184	while (len--);	257	while (len--);
185	#endif	258	#endif
186	continue;
187	}
188	}	259	}
189	else if (ip == in_end)	260	else
190	break;
191
192	/* one more literal byte we must copy */
193	lit++;
194	ip++;
195
196	if (lit == MAX_LIT)
197	{	261	{
198	if (op + 1 + MAX_LIT >= out_end)	262	/* one more literal byte we must copy */
		263	if (expect_false (op >= out_end))
199	return 0;	264	return 0;
200		265
201	*op++ = MAX_LIT - 1;	266	lit++; op++ = ip++;
202	#if USE_MEMCPY	267
203	memcpy (op, ip - MAX_LIT, MAX_LIT);	268	if (expect_false (lit == MAX_LIT))
204	op += MAX_LIT;
205	lit = 0;
206	#else
207	lit = -lit;
208	do	269	{
209	*op++ = ip[lit];	270	op [- lit - 1] = lit - 1; /* stop run */
210	while (++lit);	271	lit = 0; op++; /* start run */
211	#endif	272	}
212	}	273	}
213	}	274	}
214		275
215	if (lit)	276	if (op + 3 > out_end) /* at most 3 bytes can be missing here */
		277	return 0;
		278
		279	while (ip < in_end)
216	{	280	{
217	if (op + lit + 1 >= out_end)	281	lit++; op++ = ip++;
218	return 0;
219		282
220	*op++ = lit - 1;	283	if (expect_false (lit == MAX_LIT))
221	lit = -lit;	284	{
222	do	285	op [- lit - 1] = lit - 1; /* stop run */
223	*op++ = ip[lit];	286	lit = 0; op++; /* start run */
224	while (++lit);	287	}
225	}	288	}
226		289
		290	op [- lit - 1] = lit - 1; /* end run */
		291	op -= !lit; /* undo run if length is zero */
		292
227	return op - (u8 *) out_data;	293	return op - (u8 *)out_data;
228	}	294	}
		295

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Comparing liblzf/lzf_c.c (file contents): Revision 1.6 by pcg, Tue Apr 20 18:11:58 2004 UTC vs. Revision 1.35 by root, Sat Aug 30 06:43:38 2008 UTC

Diff Legend

Comparing liblzf/lzf_c.c (file contents):
Revision 1.6 by pcg, Tue Apr 20 18:11:58 2004 UTC vs.
Revision 1.35 by root, Sat Aug 30 06:43:38 2008 UTC