[ViewVC] Diff of: cvs/liblzf/lzf

Comparing liblzf/lzf_c.c (file contents):
Revision 1.18 by root, Tue Nov 13 08:17:38 2007 UTC vs.
Revision 1.50 by root, Mon Jun 29 23:34:41 2015 UTC

…		…
1	/*	1	/*
2	* Copyright (c) 2000-2007 Marc Alexander Lehmann <schmorp@schmorp.de>	2	* Copyright (c) 2000-2010,2012 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	*	13	*
14	* 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
15	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-	15	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
16	* CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO	16	* CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
17	* 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-
18	* CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,	18	* CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
38		38
39	#define HSIZE (1 << (HLOG))	39	#define HSIZE (1 << (HLOG))
40		40
41	/*	41	/*
42	* don't play with this unless you benchmark!	42	* don't play with this unless you benchmark!
43	* decompression is not dependent on the hash function	43	* the data format is not dependent on the hash function.
44	* the hashing function might seem strange, just believe me	44	* the hash function might seem strange, just believe me,
45	* it works ;)	45	* it works ;)
46	*/	46	*/
47	#ifndef FRST	47	#ifndef FRST
48	# define FRST(p) (((p[0]) << 8) \| p[1])	48	# define FRST(p) (((p[0]) << 8) \| p[1])
49	# 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
50	# define IDX(h) ((((h ^ (h << 5)) >> (38 - HLOG)) - h5) & (HSIZE - 1))	56	# define IDX(h) ((((h ^ (h << 5)) >> (38 - HLOG)) - h5) & (HSIZE - 1))
51	/# define IDX(h) ((ip[0] 121 ^ ip[1] * 33 ^ ip[2] * 1) & (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))
52	#endif	64	# endif
53	/*	65	#endif
54	* IDX works because it is very similar to a multiplicative hash, e.g.
55	* ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1))
56	* the latter is also quite fast on newer CPUs, and compresses similarly.
57	*
58	* the next one is also quite good, albeit slow ;)
59	* (int)(cos(h & 0xffffff) * 1e6)
60	*/
61		66
62	#if 0	67	#if 0
63	/* original lzv-like hash function, much worse and thus slower */	68	/* original lzv-like hash function, much worse and thus slower */
64	# define FRST(p) (p[0] << 5) ^ p[1]	69	# define FRST(p) (p[0] << 5) ^ p[1]
65	# define NEXT(v,p) ((v) << 5) ^ p[2]	70	# define NEXT(v,p) ((v) << 5) ^ p[2]
66	# define IDX(h) ((h) & (HSIZE - 1))	71	# define IDX(h) ((h) & (HSIZE - 1))
67	#endif	72	#endif
68		73
69	#define MAX_LIT (1 << 5)
70	#define MAX_OFF (1 << 13)
71	#define MAX_REF ((1 << 8) + (1 << 3))
72
73	#if (__i386 \|\| __amd64) && __GNUC__ >= 3
74	# define lzf_movsb(dst, src, len) \
75	asm ("rep movsb" \
76	: "=D" (dst), "=S" (src), "=c" (len) \
77	: "0" (dst), "1" (src), "2" (len));
78	#endif
79
80	#if __GNUC__ >= 3	74	#if __GNUC__ >= 3
81	# define expect(expr,value) __builtin_expect ((expr),(value))	75	# define expect(expr,value) __builtin_expect ((expr),(value))
82	# define inline inline	76	# define inline inline
83	#else	77	#else
84	# define expect(expr,value) (expr)	78	# define expect(expr,value) (expr)
…		…
89	#define expect_true(expr) expect ((expr) != 0, 1)	83	#define expect_true(expr) expect ((expr) != 0, 1)
90		84
91	/*	85	/*
92	* compressed format	86	* compressed format
93	*	87	*
94	* 000LLLLL <L+1> ; literal	88	* 000LLLLL <L+1> ; literal, L+1=1..33 octets
95	* LLLooooo oooooooo ; backref L	89	* LLLooooo oooooooo ; backref L+1=1..7 octets, o+1=1..4096 offset
96	* 111ooooo LLLLLLLL oooooooo ; backref L+7	90	* 111ooooo LLLLLLLL oooooooo ; backref L+8 octets, o+1=1..4096 offset
97	*	91	*
98	*/	92	*/
99		93
100	unsigned int	94	unsigned int
101	lzf_compress (const void *const in_data, unsigned int in_len,	95	lzf_compress (const void *const in_data, unsigned int in_len,
…		…
106	)	100	)
107	{	101	{
108	#if !LZF_STATE_ARG	102	#if !LZF_STATE_ARG
109	LZF_STATE htab;	103	LZF_STATE htab;
110	#endif	104	#endif
111	const u8 **hslot;
112	const u8 ip = (const u8 )in_data;	105	const u8 ip = (const u8 )in_data;
113	u8 op = (u8 )out_data;	106	u8 op = (u8 )out_data;
114	const u8 *in_end = ip + in_len;	107	const u8 *in_end = ip + in_len;
115	u8 *out_end = op + out_len;	108	u8 *out_end = op + out_len;
116	const u8 *ref;	109	const u8 *ref;
117		110
118	unsigned int hval = FRST (ip);	111	/* off requires a type wide enough to hold a general pointer difference.
		112	* ISO C doesn't have that (size_t might not be enough and ptrdiff_t only
		113	* works for differences within a single object). We also assume that
		114	* no bit pattern traps. Since the only platform that is both non-POSIX
		115	* and fails to support both assumptions is windows 64 bit, we make a
		116	* special workaround for it.
		117	*/
		118	#if defined (_WIN32) && defined (_M_X64)
		119	/* workaround for missing POSIX compliance */
		120	#if __GNUC__
		121	unsigned long long off;
		122	#else
		123	unsigned __int64 off;
		124	#endif
		125	#else
119	unsigned long off;	126	unsigned long off;
120	int lit = 0;	127	#endif
		128	unsigned int hval;
		129	int lit;
		130
		131	if (!in_len \|\| !out_len)
		132	return 0;
121		133
122	#if INIT_HTAB	134	#if INIT_HTAB
123	memset (htab, 0, sizeof (htab));	135	memset (htab, 0, sizeof (htab));
124	# if 0	136	#endif
125	for (hslot = htab; hslot < htab + HSIZE; hslot++)	137
126	*hslot++ = ip;	138	lit = 0; op++; /* start run */
		139
		140	hval = FRST (ip);
		141	while (ip < in_end - 2)
		142	{
		143	LZF_HSLOT *hslot;
		144
		145	hval = NEXT (hval, ip);
		146	hslot = htab + IDX (hval);
		147	ref = hslot + LZF_HSLOT_BIAS; hslot = ip - LZF_HSLOT_BIAS;
		148
		149	if (1
		150	#if INIT_HTAB
		151	&& ref < ip /* the next test will actually take care of this, but this is faster */
		152	#endif
		153	&& (off = ip - ref - 1) < LZF_MAX_OFF
		154	&& ref > (u8 *)in_data
		155	&& ref[2] == ip[2]
		156	#if STRICT_ALIGN
		157	&& ((ref[1] << 8) \| ref[0]) == ((ip[1] << 8) \| ip[0])
		158	#else
		159	&& (u16 )ref == (u16 )ip
		160	#endif
		161	)
		162	{
		163	/* match found at ref++ /
		164	unsigned int len = 2;
		165	unsigned int maxlen = in_end - ip - len;
		166	maxlen = maxlen > LZF_MAX_REF ? LZF_MAX_REF : maxlen;
		167
		168	if (expect_false (op + 3 + 1 >= out_end)) /* first a faster conservative test */
		169	if (op - !lit + 3 + 1 >= out_end) /* second the exact but rare test */
		170	return 0;
		171
		172	op [- lit - 1] = lit - 1; /* stop run */
		173	op -= !lit; /* undo run if length is zero */
		174
		175	for (;;)
		176	{
		177	if (expect_true (maxlen > 16))
		178	{
		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	len++; if (ref [len] != ip [len]) break;
		183
		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	len++; if (ref [len] != ip [len]) break;
		188
		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	len++; if (ref [len] != ip [len]) break;
		193
		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	len++; if (ref [len] != ip [len]) break;
		198	}
		199
		200	do
		201	len++;
		202	while (len < maxlen && ref[len] == ip[len]);
		203
		204	break;
		205	}
		206
		207	len -= 2; /* len is now #octets - 1 */
		208	ip++;
		209
		210	if (len < 7)
		211	{
		212	*op++ = (off >> 8) + (len << 5);
		213	}
		214	else
		215	{
		216	*op++ = (off >> 8) + ( 7 << 5);
		217	*op++ = len - 7;
		218	}
		219
		220	*op++ = off;
		221
		222	lit = 0; op++; /* start run */
		223
		224	ip += len + 1;
		225
		226	if (expect_false (ip >= in_end - 2))
		227	break;
		228
		229	#if ULTRA_FAST \|\| VERY_FAST
		230	--ip;
		231	# if VERY_FAST && !ULTRA_FAST
		232	--ip;
127	# endif	233	# endif
		234	hval = FRST (ip);
		235
		236	hval = NEXT (hval, ip);
		237	htab[IDX (hval)] = ip - LZF_HSLOT_BIAS;
		238	ip++;
		239
		240	# if VERY_FAST && !ULTRA_FAST
		241	hval = NEXT (hval, ip);
		242	htab[IDX (hval)] = ip - LZF_HSLOT_BIAS;
		243	ip++;
128	#endif	244	# endif
		245	#else
		246	ip -= len + 1;
129		247
130	for (;;)	248	do
131	{	249	{
132	if (expect_true (ip < in_end - 2))	250	hval = NEXT (hval, ip);
		251	htab[IDX (hval)] = ip - LZF_HSLOT_BIAS;
		252	ip++;
		253	}
		254	while (len--);
		255	#endif
		256	}
		257	else
133	{	258	{
134	hval = NEXT (hval, ip);
135	hslot = htab + IDX (hval);
136	ref = hslot; hslot = ip;
137
138	if (1
139	#if INIT_HTAB && !USE_MEMCPY
140	&& ref < ip /* the next test will actually take care of this, but this is faster */
141	#endif
142	&& (off = ip - ref - 1) < MAX_OFF
143	&& ip + 4 < in_end
144	&& ref > (u8 *)in_data
145	#if STRICT_ALIGN
146	&& ref[0] == ip[0]
147	&& ref[1] == ip[1]
148	&& ref[2] == ip[2]
149	#else
150	&& (u16 )ref == (u16 )ip
151	&& ref[2] == ip[2]
152	#endif
153	)
154	{
155	/* match found at ref++ /
156	unsigned int len = 2;
157	unsigned int maxlen = in_end - ip - len;
158	maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
159
160	if (expect_false (op + lit + 1 + 3 >= out_end))
161	return 0;
162
163	if (lit)
164	{
165	*op++ = lit - 1;
166	lit = -lit;
167	do
168	*op++ = ip[lit];
169	while (++lit);
170	}
171
172	for (;;)
173	{
174	if (expect_true (ip < in_end - 2 - 8 && maxlen > 8))
175	{
176	len++; if (ref [len] != ip [len]) break;
177	len++; if (ref [len] != ip [len]) break;
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	len++; if (ref [len] != ip [len]) break;
183	len++; if (ref [len] != ip [len]) break;
184	}
185
186	do
187	len++;
188	while (len < maxlen && ref[len] == ip[len]);
189
190	break;
191	}
192
193	len -= 2;
194	ip++;
195
196	if (len < 7)
197	{
198	*op++ = (off >> 8) + (len << 5);
199	}
200	else
201	{
202	*op++ = (off >> 8) + ( 7 << 5);
203	*op++ = len - 7;
204	}
205
206	*op++ = off;
207
208	#if ULTRA_FAST \|\| VERY_FAST
209	ip += len;
210	#if VERY_FAST && !ULTRA_FAST
211	--ip;
212	#endif
213	hval = FRST (ip);
214
215	hval = NEXT (hval, ip);
216	htab[IDX (hval)] = ip;
217	ip++;
218
219	#if VERY_FAST && !ULTRA_FAST
220	hval = NEXT (hval, ip);
221	htab[IDX (hval)] = ip;
222	ip++;
223	#endif
224	#else
225	do
226	{
227	hval = NEXT (hval, ip);
228	htab[IDX (hval)] = ip;
229	ip++;
230	}
231	while (len--);
232	#endif
233	continue;
234	}
235	}
236	else if (expect_false (ip == in_end))
237	break;
238
239	/* one more literal byte we must copy */	259	/* one more literal byte we must copy */
240	lit++;	260	if (expect_false (op >= out_end))
241	ip++;
242
243	if (expect_false (lit == MAX_LIT))
244	{
245	if (op + 1 + MAX_LIT >= out_end)
246	return 0;	261	return 0;
247		262
248	*op++ = MAX_LIT - 1;	263	lit++; op++ = ip++;
249		264
250	#ifdef lzf_movsb	265	if (expect_false (lit == LZF_MAX_LIT))
251	ip -= lit;
252	lzf_movsb (op, ip, lit);
253	#else
254	lit = -lit;
255	do	266	{
256	*op++ = ip[lit];	267	op [- lit - 1] = lit - 1; /* stop run */
257	while (++lit);	268	lit = 0; op++; /* start run */
258	#endif	269	}
259	}	270	}
260	}	271	}
261		272
262	if (lit)	273	if (op + 3 > out_end) /* at most 3 bytes can be missing here */
		274	return 0;
		275
		276	while (ip < in_end)
263	{	277	{
264	if (op + lit + 1 >= out_end)	278	lit++; op++ = ip++;
265	return 0;
266		279
267	*op++ = lit - 1;	280	if (expect_false (lit == LZF_MAX_LIT))
268	#ifdef lzf_movsb	281	{
269	ip -= lit;	282	op [- lit - 1] = lit - 1; /* stop run */
270	lzf_movsb (op, ip, lit);	283	lit = 0; op++; /* start run */
271	#else	284	}
272	lit = -lit;
273	do
274	*op++ = ip[lit];
275	while (++lit);
276	#endif
277	}	285	}
278		286
		287	op [- lit - 1] = lit - 1; /* end run */
		288	op -= !lit; /* undo run if length is zero */
		289
279	return op - (u8 *) out_data;	290	return op - (u8 *)out_data;
280	}	291	}
281		292

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Comparing liblzf/lzf_c.c (file contents): Revision 1.18 by root, Tue Nov 13 08:17:38 2007 UTC vs. Revision 1.50 by root, Mon Jun 29 23:34:41 2015 UTC

Diff Legend

Comparing liblzf/lzf_c.c (file contents):
Revision 1.18 by root, Tue Nov 13 08:17:38 2007 UTC vs.
Revision 1.50 by root, Mon Jun 29 23:34:41 2015 UTC