tools/gigabeat.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2006 by Christian Hack
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24
  25 extern void int2le(unsigned int val, unsigned char* addr);
  26 extern unsigned int le2int(unsigned char* buf);
  27
  28 static FILE * openinfile( const char * filename )
  29 {
  30     FILE * F = fopen( filename, "rb" );
  31     if( F == NULL )
  32     {
  33         fprintf( stderr, "Couldn't open input file %s\n", filename );
  34         perror( "Error was " );
  35         exit( -1 );
  36     };
  37     return F;
  38 }
  39
  40 static FILE * openoutfile( const char * filename )
  41 {
  42     FILE * F = fopen( filename, "wb" );
  43     if( F == NULL )
  44     {
  45         fprintf( stderr, "Couldn't open output file %s\n", filename );
  46         perror( "Error was " );
  47         exit( -1 );
  48     };
  49     return F;
  50 }
  51
  52 int gigabeat_code(char *infile, char *outfile)
  53 {
  54     FILE *in, *out;
  55     unsigned long size = 0;
  56     unsigned long bytes_read;
  57     unsigned char buf[4];
  58     unsigned long data;
  59     unsigned long key = 0x19751217;
  60
  61     in = openinfile(infile);
  62     out = openoutfile(outfile);
  63
  64     while (!feof(in)) {
  65         bytes_read = fread(buf, 1, 4, in);
  66
  67         /* Read in little-endian */
  68         data = le2int(buf);
  69
  70         data = data ^ key;
  71
  72         key = key + (key << 1);
  73         key = key + 0x19751217;
  74
  75         size += bytes_read;
  76
  77         /* Write out little-endian */
  78         int2le(data, buf);
  79
  80         fwrite(buf, 1, bytes_read, out);
  81     }
  82
  83     fprintf(stderr, "File processed successfully\n" );
  84
  85     fclose(in);
  86     fclose(out);
  87     return(0);
  88 }