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comparison Meerwald-dir/gen_cox_sig.c @ 24:9f20bce6184e v0.7

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move directories, support netpbm 11
author Peter Meerwald-Stadler <pmeerw@pmeerw.net>
date Fri, 20 Dec 2024 13:08:59 +0100
parents Meerwald/gen_cox_sig.c@4987db85cfae
children
comparison
equal deleted inserted replaced
23:71dd4b96221b 24:9f20bce6184e
1 #include "wm.h"
2
3 char *progname;
4
5 void usage(void) {
6 fprintf(stderr, "usage: %s [-a n] [-d n] [-m n] [-n n] [-o file] [-s file] [-S n]\n\n", progname);
7 fprintf(stderr, "\t-a n\t\talpha factor (default 0.3)\n");
8 fprintf(stderr, "\t-d n\t\tdeviation (default 1.0)\n");
9 fprintf(stderr, "\t-h\t\tprint usage\n");
10 fprintf(stderr, "\t-m n \t\tmean value (default 0.0)\n");
11 fprintf(stderr, "\t-n n\t\twatermark length (default 100)\n");
12 fprintf(stderr, "\t-o file\t\toutput file\n");
13 fprintf(stderr, "\t-s file\t\tuse signature file's embedding information\n");
14 fprintf(stderr, "\t-S n\t\tseed\n");
15 exit(0);
16 }
17
18 int main(int argc, char *argv[]) {
19 FILE *out = stdout;
20 FILE *sig = NULL;
21
22 char output_name[MAXPATHLEN] = "(stdout)";
23 char signature_name[MAXPATHLEN];
24
25 int c;
26 int n = 100;
27 int s = 0;
28 double a = 0.3;
29 double m = 0.0;
30 double d = 1.0;
31
32 progname = argv[0];
33
34 while ((c = getopt(argc, argv, "a:d:h?m:n:o:s:S:")) != EOF) {
35 switch (c) {
36 case 'a':
37 a = atof(optarg);
38 if (a <= 0.0) {
39 fprintf(stderr, "%s: alpha factor %f out of range\n", progname, a);
40 exit(1);
41 }
42 break;
43 case 'd':
44 d = atof(optarg);
45 if (d <= 0.0) {
46 fprintf(stderr, "%s: deviation %f out of range\n", progname, d);
47 exit(1);
48 }
49 break;
50 case 'h':
51 case '?':
52 usage();
53 break;
54 case 'm':
55 m = atof(optarg);
56 break;
57 case 'n':
58 n = atoi(optarg);
59 if (n < 1 || n > 32000) {
60 fprintf(stderr, "%s: watermark length %d out of range\n", progname, n);
61 exit(1);
62 }
63 break;
64 case 'o':
65 if ((out = fopen(optarg, "w")) == NULL) {
66 fprintf(stderr, "%s: unable to open output file %s\n", progname, optarg);
67 exit(1);
68 }
69 strcpy(output_name, optarg);
70 break;
71 case 's':
72 if ((sig = fopen(optarg, "r")) == NULL) {
73 fprintf(stderr, "%s: unable to open signature file %s\n", progname, optarg);
74 exit(1);
75 }
76 strcpy(signature_name, optarg);
77 break;
78 case 'S':
79 s = atoi(optarg);
80 break;
81 }
82 }
83
84 argc -= optind;
85 argv += optind;
86
87 if (argc > 0) {
88 usage();
89 exit(1);
90 }
91
92 if (sig) {
93 char line[32];
94 fgets(line, sizeof(line), sig);
95 if (strspn(line, "CXSG") >= 4) {
96 if (n == 0)
97 fscanf(sig, "%d\n", &n);
98 else
99 fscanf(sig, "%*d\n");
100 if (a == 0.0)
101 fscanf(sig, "%lf\n", &a);
102 else
103 fscanf(sig, "%*f\n");
104 if (m == 0.0)
105 fscanf(sig, "%lf\n", &m);
106 else
107 fscanf(sig, "%*f\n");
108 if (d == 0.0)
109 fscanf(sig, "%lf\n", &d);
110 else
111 fscanf(sig, "%*f\n");
112 }
113 else {
114 fprintf(stderr, "%s: invalid signature file %s\n", progname, signature_name);
115 exit(1);
116 }
117 fclose(sig);
118 }
119
120 if (s)
121 srandom(s);
122 else
123 srandom(time(NULL) * getpid());
124
125 fprintf(out, "CXSG\n");
126 fprintf(out, "%d\n", n);
127 fprintf(out, "%f\n", a);
128 fprintf(out, "%f\n", m);
129 fprintf(out, "%f\n", d);
130
131 n >>= 1;
132 while (n > 0) {
133 double x;
134 double x1, x2;
135
136 /*
137 * Algorithm P (Polar method for normal deviates),
138 * Knuth, D., "The Art of Computer Programming", Vol. 2, 3rd Edition, p. 122
139 */
140 do {
141 x1 = 2.0 * ((random() & RAND_MAX) / ((double) RAND_MAX + 1.0)) - 1.0;
142 x2 = 2.0 * ((random() & RAND_MAX) / ((double) RAND_MAX + 1.0)) - 1.0;
143 x = x1 * x1 + x2 * x2;
144 } while (x >= 1.0);
145 x1 *= sqrt((-2.0) * log(x) / x);
146 x2 *= sqrt((-2.0) * log(x) / x);
147
148 fprintf(out, "%f\n", m + d * x1);
149 fprintf(out, "%f\n", m + d * x2);
150
151 n--;
152 }
153
154 fclose(out);
155
156 exit(0);
157 }

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