source: trunk/indexers/mg/lib/bitio_m_mem.h@ 13658

Last change on this file since 13658 was 13658, checked in by kjdon, 17 years ago

added in some x++ -> ++x changes submitted by Emanuel Dejanu
  • Property svn:executable set to *
  • Property svn:keywords set to Author Date Id Revision
File size: 5.3 KB
Line 
1/**************************************************************************
2 *
3 * bitio_m_mem.h -- Macros for bitio to memory
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 **************************************************************************
21 *
22 * This file contains macros for doing bitwise input and output on an array
23 * of chars. These routines are faster than the ones in "mems" files. But
24 * with these routines you cannot mix reads and writes on the array of chars,
25 * or multiple write, at the same time and guarantee them to work, also you
26 * cannot seek to a point and do a write. The decode routine can detect when
27 * you run off the end of the array and will produce an approate error
28 * message, and the encode routine will stop when it gets to the end of the
29 * character array.
30 *
31 **************************************************************************/
32
33#ifndef H_BITIO_M_MEM
34#define H_BITIO_M_MEM
35
36typedef struct mem_bitio_state
37 {
38 unsigned char *Base;
39 unsigned char *Pos;
40 int Remaining;
41 unsigned char Buff;
42 unsigned char Btg;
43 }
44mem_bitio_state;
45
46
47
48
49#ifndef DECODE_ERROR
50#define DECODE_ERROR (fprintf(stderr,"Unexpected EOF in \"%s\" on line %d\n",\
51 __FILE__, __LINE__), exit(1))
52#endif
53
54
55
56#define ENCODE_START(p,r) \
57 { \
58 register unsigned char *__pos = p; \
59 register unsigned char *__base = p; \
60 register int __remaining = r; \
61 register unsigned char __buff = 0; \
62 register unsigned char __btg = sizeof(__buff)*8;
63
64#define ENCODE_CONTINUE(b) \
65 { \
66 register unsigned char *__pos = (b).Pos; \
67 register unsigned char *__base = (b).Base; \
68 register int __remaining = (b).Remaining; \
69 register unsigned char __buff = (b).Buff; \
70 register unsigned char __btg = (b).Btg;
71
72#define ENCODE_BIT(b) \
73 do { \
74 --__btg; \
75 if (b) __buff |= (1 << __btg); \
76 if (!__btg) \
77 { \
78 if (__remaining) \
79 { \
80 *__pos++ = __buff; \
81 --__remaining; \
82 } \
83 __buff = 0; \
84 __btg = sizeof(__buff)*8; \
85 } \
86 } while(0)
87
88#define ENCODE_PAUSE(b) \
89 (b).Pos = __pos; \
90 (b).Base = __base; \
91 (b).Remaining = __remaining; \
92 (b).Buff = __buff; \
93 (b).Btg = __btg; \
94 }
95
96#define ENCODE_FLUSH \
97 do { \
98 if (__btg != sizeof(__buff)*8) \
99 if (__remaining) \
100 { \
101 *__pos++ = __buff; \
102 --__remaining; \
103 } \
104 __btg = sizeof(__buff)*8; \
105 } while (0)
106
107#define ENCODE_DONE \
108 ENCODE_FLUSH; \
109 }
110
111
112#define DECODE_START(p,r) \
113 { \
114 register unsigned char *__pos = p; \
115 register unsigned char *__base = p; \
116 register int __remaining = r; \
117 register unsigned char __buff = 0; \
118 register unsigned char __btg = 0;
119
120#define DECODE_CONTINUE(b) \
121 { \
122 register unsigned char *__pos = (b).Pos; \
123 register unsigned char *__base = (b).Base; \
124 register int __remaining = (b).Remaining; \
125 register unsigned char __buff = (b).Buff; \
126 register unsigned char __btg = (b).Btg;
127
128#define DECODE_ADD_FF(b) \
129 do { \
130 if (!__btg) \
131 { \
132 if (__remaining) \
133 { \
134 __buff = *__pos++; \
135 --__remaining; \
136 } \
137 else \
138 __buff = 0xff; \
139 __btg = sizeof(__buff)*8; \
140 } \
141 (b) += (b) + ((__buff >> --__btg) & 1); \
142 } while(0)
143
144#define DECODE_ADD_00(b) \
145 do { \
146 if (!__btg) \
147 { \
148 if (__remaining) \
149 { \
150 __buff = *__pos++; \
151 --__remaining; \
152 } \
153 else \
154 __buff = 0x00; \
155 __btg = sizeof(__buff)*8; \
156 } \
157 (b) += (b) + ((__buff >> --__btg) & 1); \
158 } while(0)
159
160#define DECODE_BIT (__btg ? (__buff >> --__btg) & 1 : \
161 (!__remaining ? \
162 (DECODE_ERROR, 0) : \
163 (__buff = *__pos++, __remaining--, __btg = sizeof(__buff)*8, \
164 (__buff >> --__btg) & 1)))
165
166#define DECODE_DONE ; \
167 }
168
169#define DECODE_PAUSE(b) \
170 (b).Pos = __pos; \
171 (b).Base = __base; \
172 (b).Remaining = __remaining; \
173 (b).Buff = __buff; \
174 (b).Btg = __btg; \
175 }
176
177#define DECODE_SEEK(pos) \
178 do { \
179 register long __new_pos = (pos); \
180 __pos = __base + (__new_pos >> 3); \
181 __buff = *__pos++; \
182 __btg = 8 - (__new_pos&7); \
183 } \
184 while(0)
185
186
187
188
189#endif
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