/* FIXOBJ : cleanup routine for Amiga Object files (c) 1985 John Hodgson
 
    Note : FIXOBJ attempts to remove last record filler by truncating all
    information past the last HUNK_END, providing the HUNK_END sequence
    is within the last 128-byte record. The algorithm used here could be
    thwarted if end-of-file filler happens to contain a bogus HUNK_END, or
    if a particular load file ends with anything besides HUNK_END.
 */
 
 #include <lattice/stdio.h>
 
 /* constant definitions */
 
 #define MAX16 (0xffff)
 #define REVHUNK_END (0xf203)
 #define BYTEBITS (8)
 #define ENDOFFSET (2)
 
 main(argc,argv)
 int argc;
 char *argv[];
 {
   FILE *rdptr,*wrtptr,*fopen();
   int pos;
   unsigned int media;
   long ctr;
 
 
   if (argc!=3) {
     printf("Usage : fixobj srcfile destfile\n");
     exit(0);
   }
   if ((rdptr=fopen(argv[1],"r"))==NULL) {
     printf("Error opening file %s for reading.\n",argv[1]);
     exit(0);
   }
 
 /* search last record backwards for HUNK_END combo in reverse order */
 
   media=0;
   for (ctr=-1;ctr>-128;ctr--) {
 
     /* simulate a 16-bit shift register for easy hunk check */
 
     media=(media<<BYTEBITS)&MAX16;
     fseek(rdptr,ctr,ENDOFFSET);
     media|=getc(rdptr);
     if (media == REVHUNK_END) break;
   }
   if ((media!=REVHUNK_END) || ctr==-2) {
     (ctr==-2) ? printf("No corrections made!\n"):
                 printf("Invalid load format!\n");
     fclose(rdptr);
     exit(0);
   }
   if ((wrtptr=fopen(argv[2],"w"))==NULL) {
     printf("Error opening file %s for writing.\n",argv[2]);
     fclose(rdptr);
     exit(0);
   }
 
 /* duplicate file up to HUNK_END, inclusive */
 
   pos=ftell(rdptr)+1;
   rewind(rdptr);
 
   for (ctr=0;ctr<pos;ctr++) putc(getc(rdptr),wrtptr);
 
   fclose(rdptr); fclose(wrtptr);
 }