[3745] | 1 | /**************************************************************************
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| 2 | *
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| 3 | * bitio_m_stdio.h -- Macros for bitio to a file
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| 4 | * Copyright (C) 1994 Neil Sharman
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| 5 | *
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| 6 | * This program is free software; you can redistribute it and/or modify
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| 7 | * it under the terms of the GNU General Public License as published by
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| 8 | * the Free Software Foundation; either version 2 of the License, or
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| 9 | * (at your option) any later version.
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| 10 | *
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| 11 | * This program is distributed in the hope that it will be useful,
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| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 14 | * GNU General Public License for more details.
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| 15 | *
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| 16 | * You should have received a copy of the GNU General Public License
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| 17 | * along with this program; if not, write to the Free Software
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| 18 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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| 19 | *
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| 20 | * $Id: bitio_m_stdio.h 3745 2003-02-20 21:20:24Z mdewsnip $
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| 21 | *
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| 22 | **************************************************************************
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| 23 | *
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| 24 | * This file contains macros for doing bitwise input and output on a FILE*.
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| 25 | * With these routines you cannot mix reads and writes on the FILE,
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| 26 | * or multiple writes, at the same time and guarantee them to work, also you
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| 27 | * cannot seek to a point and do a write. The decode routine can detect when
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| 28 | * you run off the end of the file and will produce an approate error message.
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| 29 | *
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| 30 | *
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| 31 | **************************************************************************/
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| 32 |
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| 33 | #ifndef H_BITIO_M_STDIO
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| 34 | #define H_BITIO_M_STDIO
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| 35 |
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| 36 | typedef struct stdio_bitio_state
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| 37 | {
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| 38 | FILE *File;
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| 39 | unsigned char Buff;
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| 40 | unsigned char Btg;
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| 41 | }
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| 42 | stdio_bitio_state;
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| 43 |
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| 44 |
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| 45 |
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| 46 | #ifndef DECODE_ERROR
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| 47 | #define DECODE_ERROR (fprintf(stderr,"Unexpected EOF in \"%s\" on line %d\n",\
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| 48 | __FILE__, __LINE__), exit(1))
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| 49 | #endif
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| 50 |
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| 51 |
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| 52 |
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| 53 | #define ENCODE_START(f) \
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| 54 | { \
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| 55 | FILE *__outfile = f; \
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| 56 | register unsigned char __buff = 0; \
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| 57 | register unsigned char __btg = sizeof(__buff)*8;
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| 58 |
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| 59 | #define ENCODE_CONTINUE(b) \
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| 60 | { \
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| 61 | FILE *__outfile = (b).File; \
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| 62 | register unsigned char __buff = (b).Buff; \
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| 63 | register unsigned char __btg = (b).Btg;
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| 64 |
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| 65 | #define ENCODE_BIT(b) \
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| 66 | do { \
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| 67 | __btg--; \
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| 68 | if (b) __buff |= (1 << __btg); \
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| 69 | if (!__btg) \
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| 70 | { \
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| 71 | putc(__buff, __outfile); \
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| 72 | __buff = 0; \
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| 73 | __btg = sizeof(__buff)*8; \
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| 74 | } \
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| 75 | } while(0)
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| 76 |
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| 77 | #define ENCODE_PAUSE(b) \
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| 78 | (b).File = __outfile; \
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| 79 | (b).Buff = __buff; \
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| 80 | (b).Btg = __btg; \
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| 81 | }
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| 82 |
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| 83 | #define ENCODE_DONE \
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| 84 | if (__btg != sizeof(__buff)*8) \
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| 85 | putc(__buff,__outfile); \
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| 86 | }
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| 87 |
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| 88 |
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| 89 | #define DECODE_START(f) \
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| 90 | { \
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| 91 | FILE *__infile = f; \
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| 92 | register unsigned char __buff = 0; \
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| 93 | register unsigned char __btg = 0;
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| 94 |
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| 95 | #define DECODE_CONTINUE(b) \
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| 96 | { \
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| 97 | FILE *__infile = (b).File; \
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| 98 | register unsigned char __buff = (b).Buff; \
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| 99 | register unsigned char __btg = (b).Btg;
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| 100 |
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| 101 | #define DECODE_ADD_FF(b) \
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| 102 | do { \
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| 103 | if (!__btg) \
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| 104 | { \
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| 105 | register int val = getc(__infile); \
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| 106 | __buff = val == EOF ? 0xff : val; \
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| 107 | __btg = sizeof(__buff)*8; \
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| 108 | } \
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| 109 | (b) += (b) + ((__buff >> --__btg) & 1); \
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| 110 | } while(0)
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| 111 |
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| 112 | #define DECODE_ADD_00(b) \
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| 113 | do { \
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| 114 | if (!__btg) \
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| 115 | { \
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| 116 | register int val = getc(__infile); \
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| 117 | __buff = val == EOF ? 0xff : val; \
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| 118 | __btg = sizeof(__buff)*8; \
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| 119 | } \
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| 120 | (b) += (b) + ((__buff >> --__btg) & 1); \
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| 121 | } while(0)
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| 122 |
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| 123 | #define DECODE_BIT (__btg ? (__buff >> --__btg) & 1 : \
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| 124 | (__buff = getc(__infile), (feof(__infile) ? \
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| 125 | (DECODE_ERROR, 0) : \
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| 126 | (__btg = sizeof(__buff)*8, (__buff >> --__btg) & 1))))
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| 127 |
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| 128 | #define DECODE_DONE ; \
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| 129 | }
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| 130 |
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| 131 | #define DECODE_PAUSE(b) \
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| 132 | (b).File = __infile; \
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| 133 | (b).Buff = __buff; \
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| 134 | (b).Btg = __btg; \
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| 135 | }
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| 136 |
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| 137 |
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| 138 | #define DECODE_SEEK(pos) \
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| 139 | do { \
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| 140 | register long __new_pos = (pos); \
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| 141 | fseek(__infile, __new_pos >> 3, 0); \
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| 142 | __buff = getc(__infile); \
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| 143 | __btg = 8 - (__new_pos&7); \
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| 144 | } \
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| 145 | while(0)
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| 146 |
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| 147 | #endif
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