[ViewVC] Diff of: cvs/liblzf/lzf

Comparing liblzf/lzf_c.c (file contents):
Revision 1.10 by root, Thu Apr 14 20:38:50 2005 UTC vs.
Revision 1.45 by root, Sun Mar 27 23:53:23 2011 UTC

…		…
1	/*	1	/*
2	* Copyright (c) 2000-2005 Marc Alexander Lehmann <schmorp@schmorp.de>	2	* Copyright (c) 2000-2010 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))
42		40
43	/*	41	/*
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	* the data format is not dependent on the hash function.
46	* the hashing function might seem strange, just believe me	44	* the hash function might seem strange, just believe me,
47	* it works ;)	45	* it works ;)
48	*/	46	*/
49	#ifndef FRST	47	#ifndef FRST
50	# define FRST(p) (((p[0]) << 8) \| p[1])	48	# define FRST(p) (((p[0]) << 8) \| p[1])
51	# define NEXT(v,p) (((v) << 8) \| p[2])	49	# define NEXT(v,p) (((v) << 8) \| p[2])
		50	# if MULTIPLICATION_IS_SLOW
		51	# if ULTRA_FAST
		52	# define IDX(h) ((( h >> (3*8 - HLOG)) - h ) & (HSIZE - 1))
		53	# elif VERY_FAST
		54	# define IDX(h) ((( h >> (38 - HLOG)) - h5) & (HSIZE - 1))
		55	# else
52	# define IDX(h) ((((h ^ (h << 5)) >> (38 - HLOG)) - h5) & (HSIZE - 1))	56	# define IDX(h) ((((h ^ (h << 5)) >> (38 - HLOG)) - h5) & (HSIZE - 1))
		57	# endif
		58	# else
		59	/* this one was developed with sesse,
		60	* and is very similar to the one in snappy.
		61	* it does need a modern enough cpu with a fast multiplication.
		62	*/
		63	# define IDX(h) (((h * 0x1e35a7bdU) >> (32 - HLOG - 8)) & (HSIZE - 1))
53	#endif	64	# endif
54	/*	65	#endif
55	* IDX works because it is very similar to a multiplicative hash, e.g.
56	* ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1))
57	* the latter is also quite fast on newer CPUs, and sligthly better
58	*
59	* the next one is also quite good, albeit slow ;)
60	* (int)(cos(h & 0xffffff) * 1e6)
61	*/
62		66
63	#if 0	67	#if 0
64	/* original lzv-like hash function, much worse and thus slower */	68	/* original lzv-like hash function, much worse and thus slower */
65	# define FRST(p) (p[0] << 5) ^ p[1]	69	# define FRST(p) (p[0] << 5) ^ p[1]
66	# define NEXT(v,p) ((v) << 5) ^ p[2]	70	# define NEXT(v,p) ((v) << 5) ^ p[2]
67	# define IDX(h) ((h) & (HSIZE - 1))	71	# define IDX(h) ((h) & (HSIZE - 1))
68	#endif	72	#endif
69		73
70	#define MAX_LIT (1 << 5)	74	#define MAX_LIT (1 << 5)
71	#define MAX_OFF (1 << 13)	75	#define MAX_OFF (1 << 13)
72	#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)
73		88
74	/*	89	/*
75	* compressed format	90	* compressed format
76	*	91	*
77	* 000LLLLL <L+1> ; literal	92	* 000LLLLL <L+1> ; literal, L+1=1..33 octets
78	* LLLooooo oooooooo ; backref L	93	* LLLooooo oooooooo ; backref L+1=1..7 octets, o+1=1..4096 offset
79	* 111ooooo LLLLLLLL oooooooo ; backref L+7	94	* 111ooooo LLLLLLLL oooooooo ; backref L+8 octets, o+1=1..4096 offset
80	*	95	*
81	*/	96	*/
82		97
83	unsigned int	98	unsigned int
84	lzf_compress (const void *const in_data, unsigned int in_len,	99	lzf_compress (const void *const in_data, unsigned int in_len,
85	void *out_data, unsigned int out_len	100	void *out_data, unsigned int out_len
86	#if LZF_STATE_ARG	101	#if LZF_STATE_ARG
87	, LZF_STATE *htab	102	, LZF_STATE htab
88	#endif	103	#endif
89	)	104	)
90	{	105	{
91	#if !LZF_STATE_ARG	106	#if !LZF_STATE_ARG
92	LZF_STATE htab;	107	LZF_STATE htab;
93	#endif	108	#endif
94	const u8 **hslot;
95	const u8 ip = (const u8 )in_data;	109	const u8 ip = (const u8 )in_data;
96	u8 op = (u8 )out_data;	110	u8 op = (u8 )out_data;
97	const u8 *in_end = ip + in_len;	111	const u8 *in_end = ip + in_len;
98	u8 *out_end = op + out_len;	112	u8 *out_end = op + out_len;
99	const u8 *ref;	113	const u8 *ref;
100		114
101	unsigned int hval = FRST (ip);	115	/* off requires a type wide enough to hold a general pointer difference.
		116	* ISO C doesn't have that (size_t might not be enough and ptrdiff_t only
		117	* works for differences within a single object). We also assume that no
		118	* no bit pattern traps. Since the only platform that is both non-POSIX
		119	* and fails to support both assumptions is windows 64 bit, we make a
		120	* special workaround for it.
		121	*/
		122	#if defined (WIN32) && defined (_M_X64)
		123	unsigned _int64 off; /* workaround for missing POSIX compliance */
		124	#else
102	unsigned long off;	125	unsigned long off;
103	int lit = 0;	126	#endif
		127	unsigned int hval;
		128	int lit;
		129
		130	if (!in_len \|\| !out_len)
		131	return 0;
104		132
105	#if INIT_HTAB	133	#if INIT_HTAB
106	# if USE_MEMCPY
107	memset (htab, 0, sizeof (htab));	134	memset (htab, 0, sizeof (htab));
108	# else
109	for (hslot = htab; hslot < htab + HSIZE; hslot++)
110	*hslot++ = ip;
111	# endif	135	#endif
112	#endif
113		136
114	for (;;)	137	lit = 0; op++; /* start run */
		138
		139	hval = FRST (ip);
		140	while (ip < in_end - 2)
115	{	141	{
116	if (ip < in_end - 2)	142	LZF_HSLOT *hslot;
		143
		144	hval = NEXT (hval, ip);
		145	hslot = htab + IDX (hval);
		146	ref = hslot + LZF_HSLOT_BIAS; hslot = ip - LZF_HSLOT_BIAS;
		147
		148	if (1
		149	#if INIT_HTAB
		150	&& ref < ip /* the next test will actually take care of this, but this is faster */
		151	#endif
		152	&& (off = ip - ref - 1) < MAX_OFF
		153	&& ref > (u8 *)in_data
		154	&& ref[2] == ip[2]
		155	#if STRICT_ALIGN
		156	&& ((ref[1] << 8) \| ref[0]) == ((ip[1] << 8) \| ip[0])
		157	#else
		158	&& (u16 )ref == (u16 )ip
		159	#endif
		160	)
117	{	161	{
118	hval = NEXT (hval, ip);
119	hslot = htab + IDX (hval);
120	ref = hslot; hslot = ip;
121
122	if (1
123	#if INIT_HTAB && !USE_MEMCPY
124	&& ref < ip /* the next test will actually take care of this, but this is faster */
125	#endif
126	&& (off = ip - ref - 1) < MAX_OFF
127	&& ip + 4 < in_end
128	&& ref > (u8 *)in_data
129	#if STRICT_ALIGN
130	&& ref[0] == ip[0]
131	&& ref[1] == ip[1]
132	&& ref[2] == ip[2]
133	#else
134	&& (u16 )ref == (u16 )ip
135	&& ref[2] == ip[2]
136	#endif
137	)
138	{
139	/* match found at ref++ /	162	/* match found at ref++ /
140	unsigned int len = 2;	163	unsigned int len = 2;
141	unsigned int maxlen = in_end - ip - len;	164	unsigned int maxlen = in_end - ip - len;
142	maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;	165	maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
143		166
144	if (op + lit + 1 + 3 >= out_end)	167	if (expect_false (op + 3 + 1 >= out_end)) /* first a faster conservative test */
		168	if (op - !lit + 3 + 1 >= out_end) /* second the exact but rare test */
145	return 0;	169	return 0;
		170
		171	op [- lit - 1] = lit - 1; /* stop run */
		172	op -= !lit; /* undo run if length is zero */
		173
		174	for (;;)
		175	{
		176	if (expect_true (maxlen > 16))
		177	{
		178	len++; if (ref [len] != ip [len]) break;
		179	len++; if (ref [len] != ip [len]) break;
		180	len++; if (ref [len] != ip [len]) break;
		181	len++; if (ref [len] != ip [len]) break;
		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	}
146		198
147	do	199	do
148	len++;	200	len++;
149	while (len < maxlen && ref[len] == ip[len]);	201	while (len < maxlen && ref[len] == ip[len]);
150		202
151	if (lit)
152	{	203	break;
153	*op++ = lit - 1;
154	lit = -lit;
155	do
156	*op++ = ip[lit];
157	while (++lit);
158	}	204	}
159		205
		206	len -= 2; /* len is now #octets - 1 */
		207	ip++;
		208
		209	if (len < 7)
		210	{
		211	*op++ = (off >> 8) + (len << 5);
		212	}
		213	else
		214	{
		215	*op++ = (off >> 8) + ( 7 << 5);
160	len -= 2;	216	*op++ = len - 7;
		217	}
		218
		219	*op++ = off;
		220
		221	lit = 0; op++; /* start run */
		222
		223	ip += len + 1;
		224
		225	if (expect_false (ip >= in_end - 2))
		226	break;
		227
		228	#if ULTRA_FAST \|\| VERY_FAST
		229	--ip;
		230	# if VERY_FAST && !ULTRA_FAST
		231	--ip;
		232	# endif
		233	hval = FRST (ip);
		234
		235	hval = NEXT (hval, ip);
		236	htab[IDX (hval)] = ip - LZF_HSLOT_BIAS;
		237	ip++;
		238
		239	# if VERY_FAST && !ULTRA_FAST
		240	hval = NEXT (hval, ip);
		241	htab[IDX (hval)] = ip - LZF_HSLOT_BIAS;
		242	ip++;
		243	# endif
		244	#else
		245	ip -= len + 1;
		246
		247	do
		248	{
		249	hval = NEXT (hval, ip);
		250	htab[IDX (hval)] = ip - LZF_HSLOT_BIAS;
161	ip++;	251	ip++;
162
163	if (len < 7)
164	{
165	*op++ = (off >> 8) + (len << 5);
166	}	252	}
167	else
168	{
169	*op++ = (off >> 8) + ( 7 << 5);
170	*op++ = len - 7;
171	}
172
173	*op++ = off;
174
175	#if ULTRA_FAST \|\| VERY_FAST
176	ip += len;
177	#if VERY_FAST && !ULTRA_FAST
178	--ip;
179	#endif
180	hval = FRST (ip);
181
182	hval = NEXT (hval, ip);
183	htab[IDX (hval)] = ip;
184	ip++;
185
186	#if VERY_FAST && !ULTRA_FAST
187	hval = NEXT (hval, ip);
188	htab[IDX (hval)] = ip;
189	ip++;
190	#endif
191	#else
192	do
193	{
194	hval = NEXT (hval, ip);
195	htab[IDX (hval)] = ip;
196	ip++;
197	}
198	while (len--);	253	while (len--);
199	#endif	254	#endif
200	continue;
201	}
202	}	255	}
203	else if (ip == in_end)	256	else
204	break;
205
206	/* one more literal byte we must copy */
207	lit++;
208	ip++;
209
210	if (lit == MAX_LIT)
211	{	257	{
212	if (op + 1 + MAX_LIT >= out_end)	258	/* one more literal byte we must copy */
		259	if (expect_false (op >= out_end))
213	return 0;	260	return 0;
214		261
215	*op++ = MAX_LIT - 1;	262	lit++; op++ = ip++;
216	#if USE_MEMCPY	263
217	memcpy (op, ip - MAX_LIT, MAX_LIT);	264	if (expect_false (lit == MAX_LIT))
218	op += MAX_LIT;
219	lit = 0;
220	#else
221	lit = -lit;
222	do	265	{
223	*op++ = ip[lit];	266	op [- lit - 1] = lit - 1; /* stop run */
224	while (++lit);	267	lit = 0; op++; /* start run */
225	#endif	268	}
226	}	269	}
227	}	270	}
228		271
229	if (lit)	272	if (op + 3 > out_end) /* at most 3 bytes can be missing here */
		273	return 0;
		274
		275	while (ip < in_end)
230	{	276	{
231	if (op + lit + 1 >= out_end)	277	lit++; op++ = ip++;
232	return 0;
233		278
234	*op++ = lit - 1;	279	if (expect_false (lit == MAX_LIT))
235	lit = -lit;	280	{
236	do	281	op [- lit - 1] = lit - 1; /* stop run */
237	*op++ = ip[lit];	282	lit = 0; op++; /* start run */
238	while (++lit);	283	}
239	}	284	}
240		285
		286	op [- lit - 1] = lit - 1; /* end run */
		287	op -= !lit; /* undo run if length is zero */
		288
241	return op - (u8 *) out_data;	289	return op - (u8 *)out_data;
242	}	290	}
		291

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Comparing liblzf/lzf_c.c (file contents): Revision 1.10 by root, Thu Apr 14 20:38:50 2005 UTC vs. Revision 1.45 by root, Sun Mar 27 23:53:23 2011 UTC

Diff Legend

Comparing liblzf/lzf_c.c (file contents):
Revision 1.10 by root, Thu Apr 14 20:38:50 2005 UTC vs.
Revision 1.45 by root, Sun Mar 27 23:53:23 2011 UTC