#include "stdio.h"
#include "stdlib.h"

#define SWAP(x) ( ((x) << 24) | \
         (((x) << 8) & 0x00ff0000) | \
         (((x) >> 8) & 0x0000ff00) | \
         ((x) >> 24) )
#define FIX(x) (*(unsigned *)&(x) = \
         SWAP(*(unsigned *)&(x)))

/*
   Turn the AVS X file into tga
   Write to stdout, so "normal" usage will be
      x2tga bla.x > bla.tga
   Note that this code doesn't buffer the data so the image
   will appear in the same orientation as the X file, that is,
   top to bottom, left to right.
*/

void BM_WriteHexString(FILE *,char *);

int main(int argc,char **argv)
{
   int i,j;
   int a,r,g,b;
   FILE *fptr;
   int width,height; /* Assumes 4 byte ints */

   if (argc < 2) {
      fprintf(stderr,"Usage: %s xfilename\n",argv[0]);
      exit(-1);
   }

   /* Attempt to open the file */
   if ((fptr = fopen(argv[1],"r")) == NULL) {
      fprintf(stderr,"Failed to open input file \"%s\"\n",argv[1]);
      exit(-1);
   }

   /* Read the header */
   fread(&width,sizeof(int),1,fptr);
   width = FIX(width);
   fprintf(stderr,"Width: %d\n",width);
   fread(&height,sizeof(int),1,fptr);
   height = FIX(height);
   fprintf(stderr,"Height: %d\n",height);

   /* Write the TGA header */
   BM_WriteHexString(stdout,"000002");         /* uncompressed RGB  */
   BM_WriteHexString(stdout,"0000000000");
   BM_WriteHexString(stdout,"00000000");       /* X and Y origin    */
   putc((width & 0x00ff),stdout);              /* X width           */
   putc((width & 0xff00) / 256,stdout);
   putc((height & 0x00ff),stdout);             /* Y width           */
   putc((height & 0xff00) / 256,stdout);
   BM_WriteHexString(stdout,"1800");           /* 24 bit bitmap     */

   /* Read the ARGB for each pixel */
   for (j=0;j<height;j++) {
      for (i=0;i<width;i++) {

         /* Read the current pixel */
         a = fgetc(fptr);
         r = fgetc(fptr);
         g = fgetc(fptr);
         b = fgetc(fptr);
         if (a == EOF || g == EOF || r == EOF || b == EOF) {
            fprintf(stderr,"Unexpected end of file\n");
            exit(-1);
         }

         /* 
            Do something with the pixels
            Write to raw image in this example 
         */
         putchar(b);
         putchar(g);
         putchar(r);
      }
   }

   fclose(fptr);
}

void BM_WriteHexString(FILE *fptr,char *s)
{
   int i,c;
   char hex[3];

   for (i=0;i<strlen(s);i+=2) {
      hex[0] = s[i];
      hex[1] = s[i+1];
      hex[2] = '\0';
      sscanf(hex,"%X",&c);
      fputc(c,fptr);
   }
}