[ViewVC] Diff of: cvs/liblzf/lzf

Comparing liblzf/lzf_c.c (file contents):
Revision 1.5 by pcg, Mon Dec 29 12:48:16 2003 UTC vs.
Revision 1.45 by root, Sun Mar 27 23:53:23 2011 UTC

…		…
1	/*	1	/*
2	* Copyright (c) 2000-2003 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 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
41	#define IDX(h) ((((h ^ (h << 5)) >> (38 - HLOG)) + h3) & (HSIZE - 1))	56	# define IDX(h) ((((h ^ (h << 5)) >> (38 - HLOG)) - h5) & (HSIZE - 1))
42	/*	57	# endif
43	* IDX works because it is very similar to a multiplicative hash, e.g.	58	# else
44	* (h * 57321 >> (3*8 - HLOG))	59	/* this one was developed with sesse,
45	* the next one is also quite good, albeit slow ;)	60	* and is very similar to the one in snappy.
46	* (int)(cos(h & 0xffffff) * 1e6)	61	* it does need a modern enough cpu with a fast multiplication.
47	*/	62	*/
		63	# define IDX(h) (((h * 0x1e35a7bdU) >> (32 - HLOG - 8)) & (HSIZE - 1))
		64	# endif
		65	#endif
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
72	#if LZF_STATE_ARG	101	#if LZF_STATE_ARG
73	, LZF_STATE *htab	102	, LZF_STATE htab
74	#endif	103	#endif
75	)	104	)
76	{	105	{
77	#if !LZF_STATE_ARG	106	#if !LZF_STATE_ARG
78	LZF_STATE htab;	107	LZF_STATE htab;
79	#endif	108	#endif
80	const u8 **hslot;
81	const u8 ip = (const u8 )in_data;	109	const u8 ip = (const u8 )in_data;
82	u8 op = (u8 )out_data;	110	u8 op = (u8 )out_data;
83	const u8 *in_end = ip + in_len;	111	const u8 *in_end = ip + in_len;
84	u8 *out_end = op + out_len;	112	u8 *out_end = op + out_len;
85	const u8 *ref;	113	const u8 *ref;
86		114
87	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
88	unsigned long off;	125	unsigned long off;
89	int lit = 0;	126	#endif
		127	unsigned int hval;
		128	int lit;
		129
		130	if (!in_len \|\| !out_len)
		131	return 0;
90		132
91	#if INIT_HTAB	133	#if INIT_HTAB
92	# if USE_MEMCPY
93	memset (htab, 0, sizeof (htab));	134	memset (htab, 0, sizeof (htab));
94	# else
95	for (hslot = htab; hslot < htab + HSIZE; hslot++)
96	*hslot++ = ip;
97	# endif	135	#endif
98	#endif
99		136
100	for (;;)	137	lit = 0; op++; /* start run */
		138
		139	hval = FRST (ip);
		140	while (ip < in_end - 2)
101	{	141	{
102	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	)
103	{	161	{
104	hval = NEXT (hval, ip);
105	hslot = htab + IDX (hval);
106	ref = hslot; hslot = ip;
107
108	if (1
109	#if INIT_HTAB && !USE_MEMCPY
110	&& ref < ip /* the next test will actually take care of this, but this is faster */
111	#endif
112	&& (off = ip - ref - 1) < MAX_OFF
113	&& ip + 4 < in_end
114	&& ref > (u8 *)in_data
115	#if STRICT_ALIGN
116	&& ref[0] == ip[0]
117	&& ref[1] == ip[1]
118	&& ref[2] == ip[2]
119	#else
120	&& (u16 )ref == (u16 )ip
121	&& ref[2] == ip[2]
122	#endif
123	)
124	{
125	/* match found at ref++ /	162	/* match found at ref++ /
126	unsigned int len = 2;	163	unsigned int len = 2;
127	unsigned int maxlen = in_end - ip - len;	164	unsigned int maxlen = in_end - ip - len;
128	maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;	165	maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
		166
		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 */
		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	}
129		198
130	do	199	do
131	len++;	200	len++;
132	while (len < maxlen && ref[len] == ip[len]);	201	while (len < maxlen && ref[len] == ip[len]);
133		202
134	if (op + lit + 1 + 3 >= out_end)
135	return 0;
136
137	if (lit)
138	{	203	break;
139	*op++ = lit - 1;
140	lit = -lit;
141	do
142	*op++ = ip[lit];
143	while (++lit);
144	}	204	}
145		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);
146	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;
147	ip++;	251	ip++;
148
149	if (len < 7)
150	{
151	*op++ = (off >> 8) + (len << 5);
152	}	252	}
153	else
154	{
155	*op++ = (off >> 8) + ( 7 << 5);
156	*op++ = len - 7;
157	}
158
159	*op++ = off;
160
161	#if ULTRA_FAST
162	ip += len;
163	hval = FRST (ip);
164	hval = NEXT (hval, ip);
165	htab[IDX (hval)] = ip;
166	ip++;
167	#else
168	do
169	{
170	hval = NEXT (hval, ip);
171	htab[IDX (hval)] = ip;
172	ip++;
173	}
174	while (len--);	253	while (len--);
175	#endif	254	#endif
176	continue;
177	}
178	}	255	}
179	else if (ip == in_end)	256	else
180	break;
181
182	/* one more literal byte we must copy */
183	lit++;
184	ip++;
185
186	if (lit == MAX_LIT)
187	{	257	{
188	if (op + 1 + MAX_LIT >= out_end)	258	/* one more literal byte we must copy */
		259	if (expect_false (op >= out_end))
189	return 0;	260	return 0;
190		261
191	*op++ = MAX_LIT - 1;	262	lit++; op++ = ip++;
192	#if USE_MEMCPY	263
193	memcpy (op, ip - MAX_LIT, MAX_LIT);	264	if (expect_false (lit == MAX_LIT))
194	op += MAX_LIT;
195	lit = 0;
196	#else
197	lit = -lit;
198	do	265	{
199	*op++ = ip[lit];	266	op [- lit - 1] = lit - 1; /* stop run */
200	while (++lit);	267	lit = 0; op++; /* start run */
201	#endif	268	}
202	}	269	}
203	}	270	}
204		271
205	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)
206	{	276	{
207	if (op + lit + 1 >= out_end)	277	lit++; op++ = ip++;
208	return 0;
209		278
210	*op++ = lit - 1;	279	if (expect_false (lit == MAX_LIT))
211	lit = -lit;	280	{
212	do	281	op [- lit - 1] = lit - 1; /* stop run */
213	*op++ = ip[lit];	282	lit = 0; op++; /* start run */
214	while (++lit);	283	}
215	}	284	}
216		285
		286	op [- lit - 1] = lit - 1; /* end run */
		287	op -= !lit; /* undo run if length is zero */
		288
217	return op - (u8 *) out_data;	289	return op - (u8 *)out_data;
218	}	290	}
		291

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing liblzf/lzf_c.c (file contents): Revision 1.5 by pcg, Mon Dec 29 12:48:16 2003 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 1.5 by pcg, Mon Dec 29 12:48:16 2003 UTC vs.
Revision 1.45 by root, Sun Mar 27 23:53:23 2011 UTC