/*
 * mydump.c
 *
 * Create a hex dump in the format preferred by hpa
 *
 */

#include <stdio.h>
#include <stdlib.h>

#define BLOCK_SIZE 4096

static int my_isprint(unsigned char ch)
{
  return ( (ch & 0x60) && ch != 0x7f && ch != 0xa0 );
}

void dump_file(FILE *in, FILE *out, unsigned long offset)
{
  unsigned char buffer[BLOCK_SIZE], *lptr, *dptr;
  int nb, nl, i;
  long addr;

  if ( offset )
    fseek(in, offset, SEEK_SET);

  addr = ftell(in);
  if ( addr == -1 ) addr = 0;

  while ( (nb = fread(buffer, 1, BLOCK_SIZE, in)) > 0 ) {
    dptr = buffer;
    while ( nb ) {
      fprintf(out, "%08lx   ", addr);
      nl = ( nb < 16 ) ? nb : 16;
      addr += nl;
      nb -= nl;

      lptr = dptr;

      for ( i = 0 ; i < 16 ; i++ ) {
	if ( i >= nl )
	  fprintf(out, "  ");
	else
	  fprintf(out, "%02x", *dptr++);

	putc(i == 7 ? '-' : ' ', out);
      }

      dptr = lptr;
      fprintf(out, "  ");
      
      for ( i = 0 ; i < 16 ; i++ ) {
	if ( i >= nl )
	  putc(' ', out);
	else if ( my_isprint(*dptr) )
	  putc(*dptr, out);
	else
	  putc('.', out);

	dptr++;
      }
      putc('\n', out);
    }
  }
}


int main(int argc, char *argv[])
{
  FILE *f;
  int i;
  unsigned long offset = 0;

  if ( argc > 1 ) {
    for ( i = 1 ; i < argc ; i++ ) {
      if ( argv[i][0] == '-' ) {
	if ( argv[i][1] == 'o' && i < argc-1 ) {
	  offset = strtoul(argv[++i], NULL, 0);
	}
      } else {
	if ( !(f = fopen(argv[i], "rb")) )
	  perror(argv[i]);
	else {
	  printf("\n--- %s\n", argv[i]);
	  dump_file(f,stdout,offset);
	  fclose(f);
	}
      }
    }
  } else {
    dump_file(stdin, stdout, 0);
  }

  return 0;
}