[ViewVC] Diff of: cvs/liblzf/lzf

Comparing liblzf/lzf_c.c (file contents):
Revision 1.1 by root, Sun Jun 9 22:41:34 2002 UTC vs.
Revision 1.44 by root, Tue Jun 1 09:11:33 2010 UTC

…		…
1	/*	1	/*
2	* Copyright (c) 2000 Marc Alexander Lehmann <pcg@goof.com>	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-
22	* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;	19	* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
23	* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,	20	* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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.
		24	*
		25	* Alternatively, the contents of this file may be used under the terms of
		26	* the GNU General Public License ("GPL") version 2 or any later version,
		27	* in which case the provisions of the GPL are applicable instead of
		28	* the above. If you wish to allow the use of your version of this file
		29	* only under the terms of the GPL and not to allow others to use your
		30	* version of this file under the BSD license, indicate your decision
		31	* by deleting the provisions above and replace them with the notice
		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
		34	* either the BSD or the GPL.
27	*/	35	*/
28		36
29	#include "lzfP.h"	37	#include "lzfP.h"
30		38
31	#define HSIZE (1 << (HLOG))	39	#define HSIZE (1 << (HLOG))
32		40
33	/*	41	/*
34	* don't play with this unless you benchmark!	42	* don't play with this unless you benchmark!
35	* decompression is not dependent on the hash function	43	* the data format is not dependent on the hash function.
36	* the hashing function might seem strange, just believe me	44	* the hash function might seem strange, just believe me,
37	* it works ;)	45	* it works ;)
38	*/	46	*/
		47	#ifndef FRST
39	#define FRST(p) (((p[0]) << 8) + p[1])	48	# define FRST(p) (((p[0]) << 8) \| p[1])
40	#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
41	#define IDX(h) ((((h ^ (h << 4)) >> (38 - HLOG)) + h3) & (HSIZE - 1))	55	# define IDX(h) ((((h ^ (h << 5)) >> (38 - HLOG)) - h5) & (HSIZE - 1))
		56	# endif
		57	#endif
42	/*	58	/*
43	* 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.
44	* (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	*
45	* the next one is also quite good, albeit slow ;)	63	* the next one is also quite good, albeit slow ;)
46	* (int)(cos(h & 0xffffff) * 1e6)	64	* (int)(cos(h & 0xffffff) * 1e6)
47	*/	65	*/
48		66
49	#if 0	67	#if 0
50	/* original lzv-like hash function */	68	/* original lzv-like hash function, much worse and thus slower */
51	# define FRST(p) (p[0] << 5) ^ p[1]	69	# define FRST(p) (p[0] << 5) ^ p[1]
52	# define NEXT(v,p) (v << 5) ^ p[2]	70	# define NEXT(v,p) ((v) << 5) ^ p[2]
53	# define IDX(h) (h) & (HSIZE - 1)	71	# define IDX(h) ((h) & (HSIZE - 1))
54	#endif	72	#endif
55		73
56	#define MAX_LIT (1 << 5)	74	#define MAX_LIT (1 << 5)
57	#define MAX_OFF (1 << 13)	75	#define MAX_OFF (1 << 13)
58	#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)
59		88
60	/*	89	/*
61	* compressed format	90	* compressed format
62	*	91	*
63	* 000LLLLL <L+1> ; literal	92	* 000LLLLL <L+1> ; literal, L+1=1..33 octets
64	* LLLOOOOO oooooooo ; backref L	93	* LLLooooo oooooooo ; backref L+1=1..7 octets, o+1=1..4096 offset
65	* 111OOOOO LLLLLLLL oooooooo ; backref L+7	94	* 111ooooo LLLLLLLL oooooooo ; backref L+8 octets, o+1=1..4096 offset
66	*	95	*
67	*/	96	*/
68		97
69	unsigned int	98	unsigned int
70	lzf_compress (const void *const in_data, unsigned int in_len,	99	lzf_compress (const void *const in_data, unsigned int in_len,
71	void *out_data, unsigned int out_len)	100	void *out_data, unsigned int out_len
		101	#if LZF_STATE_ARG
		102	, LZF_STATE htab
		103	#endif
		104	)
72	{	105	{
73	const u8 *htab[HSIZE];	106	#if !LZF_STATE_ARG
74	const u8 **hslot;	107	LZF_STATE htab;
		108	#endif
75	const u8 *ip = in_data;	109	const u8 ip = (const u8 )in_data;
76	u8 *op = out_data;	110	u8 op = (u8 )out_data;
77	const u8 *in_end = ip + in_len;	111	const u8 *in_end = ip + in_len;
78	u8 *out_end = op + out_len;	112	u8 *out_end = op + out_len;
79	const u8 *ref;	113	const u8 *ref;
80		114
81	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
82	unsigned long off;	125	unsigned long off;
83	int lit = 0;	126	#endif
		127	unsigned int hval;
		128	int lit;
		129
		130	if (!in_len \|\| !out_len)
		131	return 0;
84		132
85	#if INIT_HTAB	133	#if INIT_HTAB
86	# if USE_MEMCPY
87	memset (htab, 0, sizeof (htab));	134	memset (htab, 0, sizeof (htab));
88	# else
89	for (hslot = htab; hslot < htab + HSIZE; hslot++)
90	*hslot++ = ip;
91	# endif	135	#endif
92	#endif
93		136
94	do	137	lit = 0; op++; /* start run */
		138
		139	hval = FRST (ip);
		140	while (ip < in_end - 2)
95	{	141	{
		142	LZF_HSLOT *hslot;
		143
96	hval = NEXT (hval, ip);	144	hval = NEXT (hval, ip);
97	hslot = htab + IDX (hval);	145	hslot = htab + IDX (hval);
98	ref = hslot; hslot = ip;	146	ref = hslot + LZF_HSLOT_BIAS; hslot = ip - LZF_HSLOT_BIAS;
99		147
100	if (1	148	if (1
101	#if INIT_HTAB && !USE_MEMCPY	149	#if INIT_HTAB
102	&& ref < ip /* the next test will actually take care of this, but it is faster */	150	&& ref < ip /* the next test will actually take care of this, but this is faster */
103	#endif	151	#endif
104	&& (off = ip - ref - 1) < MAX_OFF	152	&& (off = ip - ref - 1) < MAX_OFF
105	&& ip + 4 < in_end
106	&& ref > (u8 *)in_data	153	&& ref > (u8 *)in_data
		154	&& ref[2] == ip[2]
107	#if STRICT_ALIGN	155	#if STRICT_ALIGN
108	&& ref[0] == ip[0]	156	&& ((ref[1] << 8) \| ref[0]) == ((ip[1] << 8) \| ip[0])
109	&& ref[1] == ip[1]
110	&& ref[2] == ip[2]
111	#else	157	#else
112	&& (u16 )ref == (u16 )ip	158	&& (u16 )ref == (u16 )ip
113	&& ref[2] == ip[2]
114	#endif	159	#endif
115	)	160	)
116	{	161	{
117	/* match found at ref++ /	162	/* match found at ref++ /
118	unsigned int len = 2;	163	unsigned int len = 2;
119	unsigned int maxlen = in_end - ip - len;	164	unsigned int maxlen = in_end - ip - len;
120	maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;	165	maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
121		166
122	do	167	if (expect_false (op + 3 + 1 >= out_end)) /* first a faster conservative test */
123	len++;	168	if (op - !lit + 3 + 1 >= out_end) /* second the exact but rare test */
		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	}
		198
		199	do
		200	len++;
124	while (len < maxlen && ref[len] == ip[len]);	201	while (len < maxlen && ref[len] == ip[len]);
125		202
126	if (op + lit + 1 + 3 >= out_end)	203	break;
127	return 0;	204	}
128		205
129	if (lit)	206	len -= 2; /* len is now #octets - 1 */
130	{	207	ip++;
131	*op++ = lit - 1;
132	lit = -lit;
133	do
134	*op++ = ip[lit];
135	while (++lit);
136	}
137		208
138	len -= 2;
139	ip++;
140
141	if (len < 7)	209	if (len < 7)
142	{	210	{
143	*op++ = (off >> 8) + (len << 5);	211	*op++ = (off >> 8) + (len << 5);
144	}	212	}
145	else	213	else
146	{	214	{
147	*op++ = (off >> 8) + ( 7 << 5);	215	*op++ = (off >> 8) + ( 7 << 5);
148	*op++ = len - 7;	216	*op++ = len - 7;
149	}	217	}
150		218
151	*op++ = off;	219	*op++ = off;
152		220
153	#if ULTRA_FAST	221	lit = 0; op++; /* start run */
		222
154	ip += len;	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
155	hval = FRST (ip);	233	hval = FRST (ip);
		234
156	hval = NEXT (hval, ip);	235	hval = NEXT (hval, ip);
157	htab[IDX (hval)] = ip;	236	htab[IDX (hval)] = ip - LZF_HSLOT_BIAS;
158	ip++;	237	ip++;
159	#else	238
160	do	239	# if VERY_FAST && !ULTRA_FAST
161	{
162	hval = NEXT (hval, ip);	240	hval = NEXT (hval, ip);
163	htab[IDX (hval)] = ip;	241	htab[IDX (hval)] = ip - LZF_HSLOT_BIAS;
164	ip++;	242	ip++;
165	}
166	while (len--);
167	#endif	243	# endif
168	}	244	#else
		245	ip -= len + 1;
		246
		247	do
		248	{
		249	hval = NEXT (hval, ip);
		250	htab[IDX (hval)] = ip - LZF_HSLOT_BIAS;
		251	ip++;
		252	}
		253	while (len--);
		254	#endif
		255	}
169	else	256	else
170	{	257	{
171	/* one more literal byte we must copy */	258	/* one more literal byte we must copy */
172	lit++;	259	if (expect_false (op >= out_end))
173	ip++;	260	return 0;
174		261
175	if (lit == MAX_LIT)	262	lit++; op++ = ip++;
176	{
177	if (op + 1 + MAX_LIT >= out_end)
178	return 0;
179		263
180	*op++ = MAX_LIT - 1;	264	if (expect_false (lit == MAX_LIT))
181	#if USE_MEMCPY	265	{
182	memcpy (op, ip - MAX_LIT, MAX_LIT);	266	op [- lit - 1] = lit - 1; /* stop run */
183	op += MAX_LIT;	267	lit = 0; op++; /* start run */
184	lit = 0;	268	}
185	#else	269	}
186	lit = -lit;
187	do
188	*op++ = ip[lit];
189	while (++lit);
190	#endif
191	}
192	}
193	}	270	}
		271
		272	if (op + 3 > out_end) /* at most 3 bytes can be missing here */
		273	return 0;
		274
194	while (ip < in_end);	275	while (ip < in_end)
195
196	if (lit)
197	{	276	{
198	if (op + lit + 1 >= out_end)	277	lit++; op++ = ip++;
199	return 0;
200		278
201	*op++ = lit - 1;	279	if (expect_false (lit == MAX_LIT))
202	lit = -lit;	280	{
203	do	281	op [- lit - 1] = lit - 1; /* stop run */
204	*op++ = ip[lit];	282	lit = 0; op++; /* start run */
205	while (++lit);	283	}
206	}	284	}
207		285
		286	op [- lit - 1] = lit - 1; /* end run */
		287	op -= !lit; /* undo run if length is zero */
		288
208	return op - (u8 *) out_data;	289	return op - (u8 *)out_data;
209	}	290	}
		291

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Comparing liblzf/lzf_c.c (file contents): Revision 1.1 by root, Sun Jun 9 22:41:34 2002 UTC vs. Revision 1.44 by root, Tue Jun 1 09:11:33 2010 UTC

Diff Legend

Comparing liblzf/lzf_c.c (file contents):
Revision 1.1 by root, Sun Jun 9 22:41:34 2002 UTC vs.
Revision 1.44 by root, Tue Jun 1 09:11:33 2010 UTC