source: trunk/indexers/mg/lib/bitio_m_random.h@ 3745

Last change on this file since 3745 was 3745, checked in by mdewsnip, 21 years ago

Addition of MG package for search and retrieval
  • Property svn:executable set to *
  • Property svn:keywords set to Author Date Id Revision
File size: 4.9 KB
Line 
1/**************************************************************************
2 *
3 * bitio_m_random.h -- Macros for bitio to a file (random access)
4 * Copyright (C) 1994 Neil Sharman
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 *
20 * $Id: bitio_m_random.h 3745 2003-02-20 21:20:24Z mdewsnip $
21 *
22 **************************************************************************
23 *
24 * This file contains macros for doing bitwise input and output on an array
25 * of chars. These routines are slower than the ones in "mem" files. but
26 * with these routines you can mix reads and writes, or multiple writes, on
27 * the array of chars at the same time and guarantee them to work, also you
28 * can seek to a point and do a write. The decode and encode macros cannot
29 * detect when the end off the character is reached and just continue
30 * processing.
31 *
32 *
33 **************************************************************************/
34
35#ifndef H_BITIO_M_RANDOM
36#define H_BITIO_M_RANDOM
37
38typedef struct random_bitio_state
39 {
40 FILE *File;
41 unsigned char *Buf;
42 unsigned long Base;
43 unsigned long Used;
44 unsigned long pos;
45 unsigned long len;
46 unsigned long sft;
47 }
48random_bitio_state;
49
50
51#define ENCODE_START(f,l) \
52 { \
53 register FILE *__file = f; \
54 register unsigned char *__buf; \
55 register unsigned long __pos = 0; \
56 register unsigned long __base = 0; \
57 register unsigned long __used = 0; \
58 register unsigned long __len = (l)-1; \
59 register unsigned long __sft = 0; \
60 while (__len) { __sft++; __len >>=1; } \
61 __len = 1<<__sft; \
62 __buf = Xmalloc(__len); \
63 fseek(__file, 0, 0); \
64 fread(__buf, 1, __len, __file);
65
66#define ENCODE_CONTINUE(b) \
67 { \
68 register FILE *__file = (b).File; \
69 register unsigned char *__buf = (b).Buf; \
70 register unsigned long __pos = (b).pos; \
71 register unsigned long __base = (b).Base; \
72 register unsigned long __used = (b).Used; \
73 register unsigned long __len = (b).len; \
74 register unsigned long __sft = (b).sft;
75
76#define SEEK fprintf(stderr, "Seek to %d\n",__base)
77#define READ fprintf(stderr, "Read of %d\n",__len)
78#define WRITE fprintf(stderr, "Write of %d\n",__used)
79
80#define WRITE_READ \
81 (__used ? (fseek(__file, __base, 0), \
82 fwrite(__buf, 1, __len, __file)) : 0, \
83 __base += __len, \
84 fseek(__file, __base, 0), \
85 fread(__buf, 1, __len, __file), \
86 __pos = 0, __used = 0)
87
88#define ENCODE_BIT(b) \
89 do { \
90 if (b) \
91 __buf[__pos>>3] |= 0x80 >> (__pos&7); \
92 else \
93 __buf[__pos>>3] &= 0xff7f >> (__pos&7); \
94 __used = 1; \
95 __pos++; \
96 if ((__pos>>3) >= __len) \
97 (void)WRITE_READ; \
98 } while(0)
99
100#define ENCODE_PAUSE(b) \
101 (b).File = __file; \
102 (b).Buf = __buf; \
103 (b).pos = __pos; \
104 (b).Base = __base; \
105 (b).Used = __used; \
106 (b).len = __len; \
107 (b).sft = __sft; \
108 }
109
110#define ENCODE_FLUSH \
111 if (__used) \
112 { \
113 fseek(__file, __base, 0); \
114 fwrite(__buf, 1, __len, __file); \
115 __used = 0; \
116 }
117
118
119
120#define ENCODE_DONE \
121 ENCODE_FLUSH; \
122 free(__buf); \
123 }
124
125
126#define DECODE_START(f,l) ENCODE_START(f,l)
127
128#define DECODE_CONTINUE(b) ENCODE_CONTINUE(b)
129
130#define DECODE_BIT \
131 (__pos++, (((__pos-1)>>3) >= __len ? WRITE_READ, __pos=1 : 0), \
132 ((__buf[(__pos-1)>>3] & (0x80 >> ((__pos-1)&7))) != 0))
133
134#define DECODE_ADD_FF(b) ((b) += (b) + DECODE_BIT)
135
136#define DECODE_ADD_00(b) DECODE_ADD_FF(b)
137
138#define DECODE_DONE ENCODE_DONE
139
140#define DECODE_PAUSE(b) ENCODE_PAUSE(b)
141
142#define ENCODE_SEEK(pos) \
143 do { \
144 if ((((pos)>>3) >= __base) && ((((pos)+7)>>3) < (__base+__len))) \
145 __pos = (pos)-(__base << 3); \
146 else \
147 { \
148 ENCODE_FLUSH; \
149 __base = (pos) >> 3; \
150 __base = ((pos) >> (__sft+3)) << __sft; \
151 fseek(__file, __base, 0); \
152 fread(__buf, 1, __len, __file); \
153 __pos = (pos)&7; \
154 __pos = (pos)&((8 << __sft)-1); \
155 } \
156 } while(0)
157
158
159#define DECODE_SEEK(pos) ENCODE_SEEK(pos)
160
161#define ENCODE_TELL ((__base << 3) + __pos)
162
163#define DECODE_TELL ENCODE_TELL
164
165
166
167
168#endif
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