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comparison miscellany/compress-4.0/atob.c @ 0:bce86c4163a3

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Initial revision
author kono
date Mon, 18 Apr 2005 23:46:02 +0900
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-1:000000000000 0:bce86c4163a3
1 /* atob: version 4.0
2 * stream filter to change printable ascii from "btoa" back into 8 bit bytes
3 * if bad chars, or Csums do not match: exit(1) [and NO output]
4 *
5 * Paul Rutter Joe Orost
6 * philabs!per petsd!joe
7 */
8
9 #include <stdio.h>
10
11 #define reg register
12
13 #define streq(s0, s1) strcmp(s0, s1) == 0
14
15 #define times85(x) ((((((x<<2)+x)<<2)+x)<<2)+x)
16
17 long int Ceor = 0;
18 long int Csum = 0;
19 long int Crot = 0;
20 long int word = 0;
21 long int bcount = 0;
22
23 fatal() {
24 fprintf(stderr, "bad format or Csum to atob\n");
25 exit(1);
26 }
27
28 #define DE(c) ((c) - '!')
29
30 decode(c)
31 reg c;
32 {
33 if (c == 'z') {
34 if (bcount != 0) {
35 fatal();
36 } else {
37 byteout(0);
38 byteout(0);
39 byteout(0);
40 byteout(0);
41 }
42 } else if ((c >= '!') && (c < ('!' + 85))) {
43 if (bcount == 0) {
44 word = DE(c);
45 ++bcount;
46 } else if (bcount < 4) {
47 word = times85(word);
48 word += DE(c);
49 ++bcount;
50 } else {
51 word = times85(word) + DE(c);
52 byteout((int)((word >> 24) & 255));
53 byteout((int)((word >> 16) & 255));
54 byteout((int)((word >> 8) & 255));
55 byteout((int)(word & 255));
56 word = 0;
57 bcount = 0;
58 }
59 } else {
60 fatal();
61 }
62 }
63
64 FILE *tmp_file;
65
66 byteout(c)
67 reg c;
68 {
69 Ceor ^= c;
70 Csum += c;
71 Csum += 1;
72 if ((Crot & 0x80000000)) {
73 Crot <<= 1;
74 Crot += 1;
75 } else {
76 Crot <<= 1;
77 }
78 Crot += c;
79 putc(c, tmp_file);
80 }
81
82 main(argc, argv)
83 char **argv;
84 {
85 reg c;
86 reg long int i;
87 char tmp_name[100];
88 char buf[100];
89 long int n1, n2, oeor, osum, orot;
90
91 if (argc != 1) {
92 fprintf(stderr,"bad args to %s\n", argv[0]);
93 exit(2);
94 }
95 sprintf(tmp_name, "/usr/tmp/atob.%x", getpid());
96 tmp_file = fopen(tmp_name, "w+");
97 if (tmp_file == NULL) {
98 fatal();
99 }
100 unlink(tmp_name); /* Make file disappear */
101 /*search for header line*/
102 for (;;) {
103 if (fgets(buf, sizeof buf, stdin) == NULL) {
104 fatal();
105 }
106 if (streq(buf, "xbtoa Begin\n")) {
107 break;
108 }
109 }
110
111 while ((c = getchar()) != EOF) {
112 if (c == '\n') {
113 continue;
114 } else if (c == 'x') {
115 break;
116 } else {
117 decode(c);
118 }
119 }
120 if(scanf("btoa End N %ld %lx E %lx S %lx R %lx\n",
121 &n1, &n2, &oeor, &osum, &orot) != 5) {
122 fatal();
123 }
124 if ((n1 != n2) || (oeor != Ceor) || (osum != Csum) || (orot != Crot)) {
125 fatal();
126 } else {
127 /*copy OK tmp file to stdout*/;
128 fseek(tmp_file, 0L, 0);
129 for (i = n1; --i >= 0;) {
130 putchar(getc(tmp_file));
131 }
132 }
133 exit(0);
134 }