liblzf/lzf_c.c

/*
 * Copyright (c) 2000-2007 Marc Alexander Lehmann <schmorp@schmorp.de>
 * 
 * Redistribution and use in source and binary forms, with or without modifica-
 * tion, are permitted provided that the following conditions are met:
 * 
 *   1.  Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 * 
 *   2.  Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License ("GPL") version 2 or any later version,
 * in which case the provisions of the GPL are applicable instead of
 * the above. If you wish to allow the use of your version of this file
 * only under the terms of the GPL and not to allow others to use your
 * version of this file under the BSD license, indicate your decision
 * by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL. If you do not delete the
 * provisions above, a recipient may use your version of this file under
 * either the BSD or the GPL.
 */

#include "lzfP.h"

#define HSIZE (1 << (HLOG))

/*
 * don't play with this unless you benchmark!
 * decompression is not dependent on the hash function
 * the hashing function might seem strange, just believe me
 * it works ;)
 */
#ifndef FRST
# define FRST(p) (((p[0]) << 8) | p[1])
# define NEXT(v,p) (((v) << 8) | p[2])
# if ULTRA_FAST
#  define IDX(h) ((( h             >> (3*8 - HLOG)) - h  ) & (HSIZE - 1))
# elif VERY_FAST
#  define IDX(h) ((( h             >> (3*8 - HLOG)) - h*5) & (HSIZE - 1))
# else
#  define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1))
# endif
#endif
/*
 * IDX works because it is very similar to a multiplicative hash, e.g.
 * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1))
 * the latter is also quite fast on newer CPUs, and compresses similarly.
 *
 * the next one is also quite good, albeit slow ;)
 * (int)(cos(h & 0xffffff) * 1e6)
 */

#if 0
/* original lzv-like hash function, much worse and thus slower */
# define FRST(p) (p[0] << 5) ^ p[1]
# define NEXT(v,p) ((v) << 5) ^ p[2]
# define IDX(h) ((h) & (HSIZE - 1))
#endif

#define        MAX_LIT        (1 <<  5)
#define        MAX_OFF        (1 << 13)
#define        MAX_REF        ((1 << 8) + (1 << 3))

#if __GNUC__ >= 3
# define expect(expr,value)         __builtin_expect ((expr),(value))
# define inline                     inline
#else
# define expect(expr,value)         (expr)
# define inline                     static
#endif

#define expect_false(expr) expect ((expr) != 0, 0)
#define expect_true(expr)  expect ((expr) != 0, 1)

/*
 * compressed format
 *
 * 000LLLLL <L+1>    ; literal
 * LLLooooo oooooooo ; backref L
 * 111ooooo LLLLLLLL oooooooo ; backref L+7
 *
 */

unsigned int
lzf_compress (const void *const in_data, unsigned int in_len,
              void *out_data, unsigned int out_len
#if LZF_STATE_ARG
              , LZF_STATE htab
#endif
              )
{
#if !LZF_STATE_ARG
  LZF_STATE htab;
#endif
  const u8 **hslot;
  const u8 *ip = (const u8 *)in_data;
        u8 *op = (u8 *)out_data;
  const u8 *in_end  = ip + in_len;
        u8 *out_end = op + out_len;
  const u8 *ref;

  /* off requires a type wide enough to hold a general pointer difference.
   * ISO C doesn't have that (size_t might not be enough and ptrdiff_t only
   * works for differences within a single object). We also assume that no
   * no bit pattern traps. Since the only platform that is both non-POSIX
   * and fails to support both assumptions is windows 64 bit, we make a
   * special workaround for it.
   */
#if defined (WIN32) && defined (_M_X64)
  unsigned _int64 off; /* workaround for missing POSIX compliance */
#else
  unsigned long off;
#endif
  unsigned int hval;
  int lit;

  if (!in_len || !out_len)
    return 0;

#if INIT_HTAB
  memset (htab, 0, sizeof (htab));
# if 0
  for (hslot = htab; hslot < htab + HSIZE; hslot++)
    *hslot++ = ip;
# endif
#endif

  lit = 0; op++; /* start run */

  hval = FRST (ip);
  while (ip < in_end - 2)
    {
      hval = NEXT (hval, ip);
      hslot = htab + IDX (hval);
      ref = *hslot; *hslot = ip;

      if (1
#if INIT_HTAB
          && ref < ip /* the next test will actually take care of this, but this is faster */
#endif
          && (off = ip - ref - 1) < MAX_OFF
          && ip + 4 < in_end
          && ref > (u8 *)in_data
#if STRICT_ALIGN
          && ref[0] == ip[0]
          && ref[1] == ip[1]
          && ref[2] == ip[2]
#else
          && *(u16 *)ref == *(u16 *)ip
          && ref[2] == ip[2]
#endif
        )
        {
          /* match found at *ref++ */
          unsigned int len = 2;
          unsigned int maxlen = in_end - ip - len;
          maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;

          op [- lit - 1] = lit - 1; /* stop run */
          op -= !lit; /* undo run if length is zero */

          if (expect_false (op + 3 + 1 >= out_end))
            return 0;

          for (;;)
            {
              if (expect_true (maxlen > 16))
                {
                  len++; if (ref [len] != ip [len]) break;
                  len++; if (ref [len] != ip [len]) break;
                  len++; if (ref [len] != ip [len]) break;
                  len++; if (ref [len] != ip [len]) break;

                  len++; if (ref [len] != ip [len]) break;
                  len++; if (ref [len] != ip [len]) break;
                  len++; if (ref [len] != ip [len]) break;
                  len++; if (ref [len] != ip [len]) break;

                  len++; if (ref [len] != ip [len]) break;
                  len++; if (ref [len] != ip [len]) break;
                  len++; if (ref [len] != ip [len]) break;
                  len++; if (ref [len] != ip [len]) break;

                  len++; if (ref [len] != ip [len]) break;
                  len++; if (ref [len] != ip [len]) break;
                  len++; if (ref [len] != ip [len]) break;
                  len++; if (ref [len] != ip [len]) break;
                }

              do
                len++;
              while (len < maxlen && ref[len] == ip[len]);

              break;
            }

          len -= 2;
          ip++;

          if (len < 7)
            {
              *op++ = (off >> 8) + (len << 5);
            }
          else
            {
              *op++ = (off >> 8) + (  7 << 5);
              *op++ = len - 7;
            }

          *op++ = off;

#if ULTRA_FAST || VERY_FAST
          ip += len;
#if VERY_FAST && !ULTRA_FAST
          --ip;
#endif
          hval = FRST (ip);

          hval = NEXT (hval, ip);
          htab[IDX (hval)] = ip;
          ip++;

#if VERY_FAST && !ULTRA_FAST
          hval = NEXT (hval, ip);
          htab[IDX (hval)] = ip;
          ip++;
#endif
#else
          do
            {
              hval = NEXT (hval, ip);
              htab[IDX (hval)] = ip;
              ip++;
            }
          while (len--);
#endif

          lit = 0; op++; /* start run */
        }
      else
        {
          /* one more literal byte we must copy */
          if (expect_false (op >= out_end))
            return 0;

          lit++; *op++ = *ip++;

          if (expect_false (lit == MAX_LIT))
            {
              op [- lit - 1] = lit - 1; /* stop run */
              lit = 0; op++; /* start run */
            }
        }
    }

  if (op + 3 > out_end) /* at most 3 bytes can be missing here */
    return 0;

  while (ip < in_end)
    {
      lit++; *op++ = *ip++;

      if (expect_false (lit == MAX_LIT))
        {
          op [- lit - 1] = lit - 1; /* stop run */
          lit = 0; op++; /* start run */
        }
    }

  op [- lit - 1] = lit - 1; /* end run */
  op -= !lit; /* undo run if length is zero */

  return op - (u8 *)out_data;
}

Revision:	1.32
Committed:	Fri May 9 12:42:50 2008 UTC (16 years ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.31:	+10 -3 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	/*
2	root	1.15	* Copyright (c) 2000-2007 Marc Alexander Lehmann <schmorp@schmorp.de>
3	root	1.1	*
4			* Redistribution and use in source and binary forms, with or without modifica-
5			* tion, are permitted provided that the following conditions are met:
6			*
7			* 1. Redistributions of source code must retain the above copyright notice,
8			* this list of conditions and the following disclaimer.
9			*
10			* 2. Redistributions in binary form must reproduce the above copyright
11			* notice, this list of conditions and the following disclaimer in the
12			* documentation and/or other materials provided with the distribution.
13			*
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-
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-
18			* CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19			* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
20			* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
21			* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
22			* ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
23			* OF THE POSSIBILITY OF SUCH DAMAGE.
24	pcg	1.6	*
25			* Alternatively, the contents of this file may be used under the terms of
26	root	1.16	* 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.
35	root	1.1	*/
36
37			#include "lzfP.h"
38
39			#define HSIZE (1 << (HLOG))
40
41			/*
42			* don't play with this unless you benchmark!
43			* decompression is not dependent on the hash function
44			* the hashing function might seem strange, just believe me
45			* it works ;)
46			*/
47	root	1.10	#ifndef FRST
48			# define FRST(p) (((p[0]) << 8) \| p[1])
49			# define NEXT(v,p) (((v) << 8) \| p[2])
50	root	1.22	# if ULTRA_FAST
51	root	1.23	# define IDX(h) ((( h >> (3*8 - HLOG)) - h ) & (HSIZE - 1))
52	root	1.22	# elif VERY_FAST
53	root	1.23	# define IDX(h) ((( h >> (38 - HLOG)) - h5) & (HSIZE - 1))
54	root	1.22	# else
55			# define IDX(h) ((((h ^ (h << 5)) >> (38 - HLOG)) - h5) & (HSIZE - 1))
56			# endif
57	root	1.10	#endif
58	root	1.1	/*
59			* IDX works because it is very similar to a multiplicative hash, e.g.
60	root	1.7	* ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1))
61	root	1.12	* the latter is also quite fast on newer CPUs, and compresses similarly.
62	root	1.7	*
63	root	1.1	* the next one is also quite good, albeit slow ;)
64			* (int)(cos(h & 0xffffff) * 1e6)
65			*/
66
67			#if 0
68	root	1.7	/* original lzv-like hash function, much worse and thus slower */
69	root	1.1	# define FRST(p) (p[0] << 5) ^ p[1]
70	root	1.2	# define NEXT(v,p) ((v) << 5) ^ p[2]
71			# define IDX(h) ((h) & (HSIZE - 1))
72	root	1.1	#endif
73
74			#define MAX_LIT (1 << 5)
75			#define MAX_OFF (1 << 13)
76	root	1.12	#define MAX_REF ((1 << 8) + (1 << 3))
77	root	1.1
78	root	1.17	#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)
88
89	root	1.1	/*
90			* compressed format
91			*
92			* 000LLLLL <L+1> ; literal
93	root	1.10	* LLLooooo oooooooo ; backref L
94			* 111ooooo LLLLLLLL oooooooo ; backref L+7
95	root	1.1	*
96			*/
97
98			unsigned int
99			lzf_compress (const void *const in_data, unsigned int in_len,
100	pcg	1.4	void *out_data, unsigned int out_len
101	pcg	1.5	#if LZF_STATE_ARG
102	root	1.11	, LZF_STATE htab
103	pcg	1.4	#endif
104			)
105	root	1.1	{
106	pcg	1.5	#if !LZF_STATE_ARG
107	pcg	1.4	LZF_STATE htab;
108			#endif
109	root	1.1	const u8 **hslot;
110	pcg	1.4	const u8 ip = (const u8 )in_data;
111			u8 op = (u8 )out_data;
112	root	1.1	const u8 *in_end = ip + in_len;
113			u8 *out_end = op + out_len;
114			const u8 *ref;
115
116	root	1.32	/* 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	root	1.31	#else
126	root	1.1	unsigned long off;
127	root	1.31	#endif
128	root	1.32	unsigned int hval;
129	root	1.22	int lit;
130
131			if (!in_len \|\| !out_len)
132			return 0;
133	root	1.1
134			#if INIT_HTAB
135	root	1.14	memset (htab, 0, sizeof (htab));
136			# if 0
137			for (hslot = htab; hslot < htab + HSIZE; hslot++)
138			*hslot++ = ip;
139	root	1.1	# endif
140			#endif
141
142	root	1.22	lit = 0; op++; /* start run */
143
144			hval = FRST (ip);
145			while (ip < in_end - 2)
146	root	1.1	{
147	root	1.22	hval = NEXT (hval, ip);
148			hslot = htab + IDX (hval);
149			ref = hslot; hslot = ip;
150	root	1.1
151	root	1.22	if (1
152	ayin	1.27	#if INIT_HTAB
153	root	1.22	&& ref < ip /* the next test will actually take care of this, but this is faster */
154	root	1.1	#endif
155	root	1.22	&& (off = ip - ref - 1) < MAX_OFF
156			&& ip + 4 < in_end
157			&& ref > (u8 *)in_data
158	root	1.1	#if STRICT_ALIGN
159	root	1.22	&& ref[0] == ip[0]
160			&& ref[1] == ip[1]
161			&& ref[2] == ip[2]
162	root	1.1	#else
163	root	1.22	&& (u16 )ref == (u16 )ip
164			&& ref[2] == ip[2]
165	root	1.1	#endif
166	root	1.22	)
167			{
168			/* match found at ref++ /
169			unsigned int len = 2;
170			unsigned int maxlen = in_end - ip - len;
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	root	1.9
176	root	1.25	if (expect_false (op + 3 + 1 >= out_end))
177			return 0;
178
179	root	1.22	for (;;)
180			{
181			if (expect_true (maxlen > 16))
182	pcg	1.5	{
183	root	1.22	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	pcg	1.5	}
203
204	root	1.22	do
205			len++;
206			while (len < maxlen && ref[len] == ip[len]);
207	root	1.18
208	root	1.22	break;
209			}
210	root	1.18
211	root	1.22	len -= 2;
212			ip++;
213	pcg	1.5
214	root	1.22	if (len < 7)
215			{
216			*op++ = (off >> 8) + (len << 5);
217			}
218			else
219			{
220			*op++ = (off >> 8) + ( 7 << 5);
221			*op++ = len - 7;
222			}
223	root	1.1
224	root	1.22	*op++ = off;
225	root	1.1
226	root	1.9	#if ULTRA_FAST \|\| VERY_FAST
227	root	1.22	ip += len;
228	root	1.9	#if VERY_FAST && !ULTRA_FAST
229	root	1.22	--ip;
230	root	1.9	#endif
231	root	1.22	hval = FRST (ip);
232	root	1.9
233	root	1.22	hval = NEXT (hval, ip);
234			htab[IDX (hval)] = ip;
235			ip++;
236	root	1.9
237			#if VERY_FAST && !ULTRA_FAST
238	root	1.22	hval = NEXT (hval, ip);
239			htab[IDX (hval)] = ip;
240			ip++;
241			#endif
242			#else
243			do
244			{
245	pcg	1.5	hval = NEXT (hval, ip);
246			htab[IDX (hval)] = ip;
247			ip++;
248	root	1.22	}
249			while (len--);
250	root	1.9	#endif
251	root	1.26
252	root	1.22	lit = 0; op++; /* start run */
253	pcg	1.5	}
254	root	1.26	else
255	pcg	1.5	{
256	root	1.26	/* one more literal byte we must copy */
257			if (expect_false (op >= out_end))
258			return 0;
259
260			lit++; op++ = ip++;
261
262			if (expect_false (lit == MAX_LIT))
263			{
264			op [- lit - 1] = lit - 1; /* stop run */
265			lit = 0; op++; /* start run */
266			}
267	pcg	1.5	}
268	root	1.1	}
269
270	root	1.29	if (op + 3 > out_end) /* at most 3 bytes can be missing here */
271	root	1.22	return 0;
272
273			while (ip < in_end)
274	root	1.1	{
275	root	1.26	lit++; op++ = ip++;
276	root	1.28
277			if (expect_false (lit == MAX_LIT))
278			{
279			op [- lit - 1] = lit - 1; /* stop run */
280			lit = 0; op++; /* start run */
281			}
282	root	1.22	}
283	root	1.1
284	root	1.24	op [- lit - 1] = lit - 1; /* end run */
285			op -= !lit; /* undo run if length is zero */
286	root	1.1
287	root	1.22	return op - (u8 *)out_data;
288	root	1.1	}
289	root	1.14