84 lines
1.1 KiB
C
84 lines
1.1 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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char **av;
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void
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usage (char *s)
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{
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fprintf (stderr, "Usage: %s [file]\n", s);
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}
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void
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process (FILE *f, char *name)
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{
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int a;
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int b; /* lo */
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int c; /* hi */
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int d; /* code */
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int i;
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unsigned char data[8192];
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for (i = 0; i < 8192; i++) {
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data[i] = getc (f);
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}
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b = 0;
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c = 0x20;
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d = 255 - 0x8c;
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#define BC (256*c + b - 8192)
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loop:
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a = data[BC];
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a ^= d;
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data[BC] = a;
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d = (d + 1) & 0xff;
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a = d;
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a ^= c;
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d = a;
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b = (b + 1) & 0xff;
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if (b != 0)
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goto noinc;
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c++;
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a = c;
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if (a == 0x40)
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goto done;
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noinc:
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goto loop;
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done:
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for (i = 0; i < 8192; i++)
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putchar (data[i]);
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}
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int
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main (int argc, char **argv)
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{
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av = argv;
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if (argc < 2) {
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process (stdin, "standard input");
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} else if (argc == 2) {
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FILE *f = fopen (argv[1], "r");
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if (f) {
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process (f, argv[1]);
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fclose (f);
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} else {
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fprintf (stderr, "%s: %s: %s\n", argv[0], argv[1],
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strerror (errno));
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exit (EXIT_FAILURE);
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}
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} else {
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usage (argv[0]);
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exit (EXIT_FAILURE);
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}
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return (EXIT_SUCCESS);
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}
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