misc/archive/scrsav.c

   1 /*  gcc -Wall -O2 scrsav.c -o scrsav
   2  *  while : ; do ./scrsav /dev/vcc/a2 /dev/vcc/a3 ; sleep 5 ; done
   3  *
   4  * --- T2-COPYRIGHT-NOTE-BEGIN ---
   5  * This copyright note is auto-generated by ./scripts/Create-CopyPatch.
   6  *
   7  * T2 SDE: misc/archive/scrsav.c
   8  * Copyright (C) 2004 - 2005 The T2 SDE Project
   9  * Copyright (C) 1998 - 2003 ROCK Linux Project
  10  *
  11  * More information can be found in the files COPYING and README.
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License as published by
  15  * the Free Software Foundation; version 2 of the License. A copy of the
  16  * GNU General Public License can be found in the file COPYING.
  17  * --- T2-COPYRIGHT-NOTE-END ---
  18  */
  19
  20 #include <stdio.h>
  21 #include <sys/types.h>
  22 #include <sys/stat.h>
  23 #include <fcntl.h>
  24 #include <unistd.h>
  25 #include <time.h>
  26 #include <stdlib.h>
  27 #include <endian.h>
  28
  29 #ifdef iMAC_CON
  30 #  define LINES 48
  31 #  define CHARS 128
  32 #else
  33 #  define LINES 25
  34 #  define CHARS 80
  35 #endif
  36
  37 #define BUFSIZE (LINES*CHARS*2)
  38 #define LINESIZE (CHARS*2)
  39
  40 int main(int argc, char ** argv) {
  41         char buffer[BUFSIZE];
  42         char miscdata[4];
  43         int fd,c,i,j;
  44
  45         if (argc != 3) {
  46                 fprintf(stderr, "Usage: %s <src-vcs> <trg-vcs>\n", argv[0]);
  47                 fprintf(stderr, "E.g.: %s /dev/vcc/a2 /dev/vcc/a3\n", argv[0]);
  48                 return 1;
  49         }
  50
  51         fd=open(argv[1], O_RDONLY);
  52         if (fd < 0) { perror(argv[1]); return 1; }
  53         read(fd, miscdata, 4);
  54         read(fd, buffer, BUFSIZE);
  55         close(fd);
  56
  57         srandom( time(NULL) + getpid() );
  58
  59         for (c=0; c<BUFSIZE-1; c+=2) {
  60 #if __BYTE_ORDER == __LITTLE_ENDIAN
  61                 i=c+1; j=c;
  62 #else
  63                 j=c+1; i=c;
  64 #endif
  65                 buffer[i] ^= buffer[j] ^ c ^ random() ;
  66                 if ( c/LINESIZE+1 != time(NULL) % LINES )
  67                         buffer[i] &= 0x0f;
  68         }
  69
  70         fd=open(argv[2], O_WRONLY);
  71         if (fd < 0) { perror(argv[2]); return 1; }
  72         write(fd, miscdata, 4);
  73         write(fd, buffer, BUFSIZE);
  74         close(fd);
  75
  76         return 0;
  77 }