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 version 2 (the "GPL"), 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])
# define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1))
/*# define IDX(h) ((ip[0] * 121 ^ ip[1] * 33 ^ ip[2] * 1) & (HSIZE-1))*/
#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 (__i386 || __amd64) && __GNUC__ >= 3
# define lzf_movsb(dst, src, len)                \
   asm ("rep movsb"                              \
        : "=D" (dst), "=S" (src), "=c" (len)     \
        :  "0" (dst),  "1" (src),  "2" (len));
#endif

/*
 * 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;

  unsigned int hval = FRST (ip);
  unsigned long off;
           int lit = 0;

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

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

          if (1
#if INIT_HTAB && !USE_MEMCPY
              && 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;

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

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

              if (lit)
                {
                  *op++ = lit - 1;
                  lit = -lit;
                  do
                    *op++ = ip[lit];
                  while (++lit);
                }

              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
              continue;
            }
        }
      else if (ip == in_end)
        break;

      /* one more literal byte we must copy */
      lit++;
      ip++;

      if (lit == MAX_LIT)
        {
          if (op + 1 + MAX_LIT >= out_end)
            return 0;

          *op++ = MAX_LIT - 1;

#ifdef lzf_movsb
          ip -= lit;
          lzf_movsb (op, ip, lit);
#else
          lit = -lit;
          do
            *op++ = ip[lit];
          while (++lit);
#endif
        }
    }

  if (lit)
    {
      if (op + lit + 1 >= out_end)
        return 0;

      *op++ = lit - 1;
#ifdef lzf_movsb
      ip -= lit;
      lzf_movsb (op, ip, lit);
#else
      lit = -lit;
      do
        *op++ = ip[lit];
      while (++lit);
#endif
    }

  return op - (u8 *) out_data;
}

Revision:	1.15
Committed:	Fri Nov 2 12:39:20 2007 UTC (16 years, 6 months ago) by root
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rel-2_1
Changes since 1.14:	+1 -4 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			* the GNU General Public License version 2 (the "GPL"), in which case the
27			* provisions of the GPL are applicable instead of the above. If you wish to
28			* allow the use of your version of this file only under the terms of the
29			* GPL and not to allow others to use your version of this file under the
30			* BSD license, indicate your decision by deleting the provisions above and
31			* replace them with the notice and other provisions required by the GPL. If
32			* you do not delete the provisions above, a recipient may use your version
33			* of this file under either the BSD or the GPL.
34	root	1.1	*/
35
36			#include "lzfP.h"
37
38			#define HSIZE (1 << (HLOG))
39
40			/*
41			* don't play with this unless you benchmark!
42			* decompression is not dependent on the hash function
43			* the hashing function might seem strange, just believe me
44			* it works ;)
45			*/
46	root	1.10	#ifndef FRST
47			# define FRST(p) (((p[0]) << 8) \| p[1])
48			# define NEXT(v,p) (((v) << 8) \| p[2])
49			# define IDX(h) ((((h ^ (h << 5)) >> (38 - HLOG)) - h5) & (HSIZE - 1))
50	root	1.13	/# define IDX(h) ((ip[0] 121 ^ ip[1] * 33 ^ ip[2] * 1) & (HSIZE-1))*/
51	root	1.10	#endif
52	root	1.1	/*
53			* IDX works because it is very similar to a multiplicative hash, e.g.
54	root	1.7	* ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1))
55	root	1.12	* the latter is also quite fast on newer CPUs, and compresses similarly.
56	root	1.7	*
57	root	1.1	* the next one is also quite good, albeit slow ;)
58			* (int)(cos(h & 0xffffff) * 1e6)
59			*/
60
61			#if 0
62	root	1.7	/* original lzv-like hash function, much worse and thus slower */
63	root	1.1	# define FRST(p) (p[0] << 5) ^ p[1]
64	root	1.2	# define NEXT(v,p) ((v) << 5) ^ p[2]
65			# define IDX(h) ((h) & (HSIZE - 1))
66	root	1.1	#endif
67
68			#define MAX_LIT (1 << 5)
69			#define MAX_OFF (1 << 13)
70	root	1.12	#define MAX_REF ((1 << 8) + (1 << 3))
71	root	1.1
72	root	1.14	#if (__i386 \|\| __amd64) && __GNUC__ >= 3
73			# define lzf_movsb(dst, src, len) \
74			asm ("rep movsb" \
75			: "=D" (dst), "=S" (src), "=c" (len) \
76			: "0" (dst), "1" (src), "2" (len));
77			#endif
78
79	root	1.1	/*
80			* compressed format
81			*
82			* 000LLLLL <L+1> ; literal
83	root	1.10	* LLLooooo oooooooo ; backref L
84			* 111ooooo LLLLLLLL oooooooo ; backref L+7
85	root	1.1	*
86			*/
87
88			unsigned int
89			lzf_compress (const void *const in_data, unsigned int in_len,
90	pcg	1.4	void *out_data, unsigned int out_len
91	pcg	1.5	#if LZF_STATE_ARG
92	root	1.11	, LZF_STATE htab
93	pcg	1.4	#endif
94			)
95	root	1.1	{
96	pcg	1.5	#if !LZF_STATE_ARG
97	pcg	1.4	LZF_STATE htab;
98			#endif
99	root	1.1	const u8 **hslot;
100	pcg	1.4	const u8 ip = (const u8 )in_data;
101			u8 op = (u8 )out_data;
102	root	1.1	const u8 *in_end = ip + in_len;
103			u8 *out_end = op + out_len;
104			const u8 *ref;
105
106			unsigned int hval = FRST (ip);
107			unsigned long off;
108			int lit = 0;
109
110			#if INIT_HTAB
111	root	1.14	memset (htab, 0, sizeof (htab));
112			# if 0
113			for (hslot = htab; hslot < htab + HSIZE; hslot++)
114			*hslot++ = ip;
115	root	1.1	# endif
116			#endif
117
118	pcg	1.5	for (;;)
119	root	1.1	{
120	pcg	1.5	if (ip < in_end - 2)
121			{
122			hval = NEXT (hval, ip);
123			hslot = htab + IDX (hval);
124			ref = hslot; hslot = ip;
125	root	1.1
126	pcg	1.5	if (1
127	root	1.1	#if INIT_HTAB && !USE_MEMCPY
128	pcg	1.5	&& ref < ip /* the next test will actually take care of this, but this is faster */
129	root	1.1	#endif
130	pcg	1.5	&& (off = ip - ref - 1) < MAX_OFF
131			&& ip + 4 < in_end
132			&& ref > (u8 *)in_data
133	root	1.1	#if STRICT_ALIGN
134	pcg	1.5	&& ref[0] == ip[0]
135			&& ref[1] == ip[1]
136			&& ref[2] == ip[2]
137	root	1.1	#else
138	pcg	1.5	&& (u16 )ref == (u16 )ip
139			&& ref[2] == ip[2]
140	root	1.1	#endif
141	pcg	1.5	)
142			{
143			/* match found at ref++ /
144			unsigned int len = 2;
145			unsigned int maxlen = in_end - ip - len;
146			maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
147
148	root	1.9	if (op + lit + 1 + 3 >= out_end)
149			return 0;
150
151	pcg	1.5	do
152			len++;
153			while (len < maxlen && ref[len] == ip[len]);
154
155			if (lit)
156			{
157			*op++ = lit - 1;
158			lit = -lit;
159			do
160			*op++ = ip[lit];
161			while (++lit);
162			}
163
164			len -= 2;
165			ip++;
166
167			if (len < 7)
168			{
169			*op++ = (off >> 8) + (len << 5);
170			}
171			else
172			{
173			*op++ = (off >> 8) + ( 7 << 5);
174			*op++ = len - 7;
175			}
176	root	1.1
177	pcg	1.5	*op++ = off;
178	root	1.1
179	root	1.9	#if ULTRA_FAST \|\| VERY_FAST
180	pcg	1.5	ip += len;
181	root	1.9	#if VERY_FAST && !ULTRA_FAST
182			--ip;
183			#endif
184	pcg	1.5	hval = FRST (ip);
185	root	1.9
186			hval = NEXT (hval, ip);
187			htab[IDX (hval)] = ip;
188			ip++;
189
190			#if VERY_FAST && !ULTRA_FAST
191	pcg	1.5	hval = NEXT (hval, ip);
192			htab[IDX (hval)] = ip;
193			ip++;
194	root	1.9	#endif
195	root	1.1	#else
196	pcg	1.5	do
197			{
198			hval = NEXT (hval, ip);
199			htab[IDX (hval)] = ip;
200			ip++;
201			}
202			while (len--);
203			#endif
204			continue;
205			}
206			}
207			else if (ip == in_end)
208			break;
209
210			/* one more literal byte we must copy */
211			lit++;
212			ip++;
213
214			if (lit == MAX_LIT)
215			{
216			if (op + 1 + MAX_LIT >= out_end)
217			return 0;
218	root	1.1
219	pcg	1.5	*op++ = MAX_LIT - 1;
220	root	1.14
221			#ifdef lzf_movsb
222			ip -= lit;
223			lzf_movsb (op, ip, lit);
224	root	1.1	#else
225	pcg	1.5	lit = -lit;
226			do
227			*op++ = ip[lit];
228			while (++lit);
229	root	1.1	#endif
230	pcg	1.5	}
231	root	1.1	}
232
233			if (lit)
234			{
235			if (op + lit + 1 >= out_end)
236			return 0;
237
238			*op++ = lit - 1;
239	root	1.14	#ifdef lzf_movsb
240			ip -= lit;
241			lzf_movsb (op, ip, lit);
242			#else
243	root	1.1	lit = -lit;
244			do
245			*op++ = ip[lit];
246			while (++lit);
247	root	1.14	#endif
248	root	1.1	}
249
250			return op - (u8 *) out_data;
251			}
252	root	1.14