#include <stdio.h>
#include <alloc.h>
#include <ip.h>

void write_pnm(image_ptr ptr, char *filename, int rows,
	       int cols, int magic_number);

main(int argc, char *argv[])
    {
    int row, byte;
    int length, i;
    FILE *fp;
    unsigned char data;
    char type;
    image_ptr buffer;
    unsigned int index;

    if(argc != 3)
	{
	printf("usage: mac2pbm <mac_file> <pbm_file>\n");
	exit(1);
	}

    if(!(fp = fopen(argv[1], "rb")))
	  {
	  printf("Can't open %s",argv[1]);
	  exit(1);
	  }

    buffer = (image_ptr) IP_MALLOC(51840);  /* storage for a 576x720 image */
    if(buffer == (image_ptr) NULL)
	{
	printf("Can't malloc enough memory for conversion \n");
	exit(1);
	}

    fseek(fp, 512, 0);  /* skip file header */

    row = 0;
    index = 0;
    while(row<720)
	{
	byte = 1;
	while(byte < 73)
	    {
	    type = fgetc(fp);
	    if(type & 0x80)                 /* check if MSB is set */
		{                           /* Run-Length encoded data */
		data = fgetc(fp);
		length = -1*type+1;       /* compute number of repeating bytes */
		for(i=0; i<length; i++)
		    buffer[index++] = data; /* repeat data */
		byte+=length;
		}
	    else
		{                           /* Non RLE data */
		for(i=0; i<(type+1); i++)
		    buffer[index++] = fgetc(fp);  /* get non-repeating data */
		byte+=(type+1);
		}
	    }
	row++;
	}
    fclose(fp);
    write_pnm(buffer, argv[2], 720, 576, PBM);
    IP_FREE(buffer);
    }