tools/byteswap.c

   1 /*
   2  * MiSoC
   3  * Copyright (C) 2007, 2008, 2009, 2010 Sebastien Bourdeauducq
   4  *
   5  * This program is free software: you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation, version 3 of the License.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include <stdlib.h>
  19 #include <string.h>
  20 #include <stdio.h>
  21
  22 int main(int argc, char *argv[])
  23 {
  24         FILE *fdi, *fdo;
  25         unsigned short wi;
  26         unsigned short wo;
  27         int i;
  28
  29         if(argc != 3) {
  30                 fprintf(stderr, "Usage: byteswap <infile> <outfile>\n");
  31                 return 1;
  32         }
  33         fdi = fopen(argv[1], "rb");
  34         if(!fdi) {
  35                 perror("Unable to open input file");
  36                 return 1;
  37         }
  38         fdo = fopen(argv[2], "w");
  39         if(!fdo) {
  40                 perror("Unable to open output file");
  41                 fclose(fdi);
  42                 return 1;
  43         }
  44         while(1) {
  45                 if(fread(&wi, 2, 1, fdi) <= 0) break;
  46                 wo = 0;
  47                 for(i=0;i<16;i++)
  48                         if(wi & (1 << i))
  49                                 wo |= (0x8000 >> i);
  50                 /* comment out the next line on big endian machines! */
  51                 wo = ((wo & 0x00ff) << 8) | ((wo & 0xff00) >> 8);
  52                 fwrite(&wo, 2, 1, fdo);
  53         }
  54         fclose(fdi);
  55         if(fclose(fdo) != 0) {
  56                 perror("Unable to close output file");
  57                 return 1;
  58         }
  59         return 0;
  60 }