/* Runlength encoder - wacco
 * Public domain
 */

#include <stdio.h>

void rle_encode(FILE *in, FILE *out) {
  char prev = fgetc(in), cur = fgetc(in);
  unsigned char n = 0;
  if(cur == EOF) {
    if(prev != EOF)
      fputc(prev, out);
    return;
  }
  if(prev == cur)
    n++;
  prev = cur;
  while((cur = fgetc(in)) != EOF) {
    if(prev == cur && n != 255)
      n++;
    else {
      fputc(prev, out);
      if(n) {
        fputc(prev, out);
        fputc(n - 1, out);
      }
      n = 0;
    }
    prev = cur;
  }
  fputc(prev, out);
  if(n) {
    fputc(prev, out);
    fputc(n - 1, out);
  }
}

int main() {
  FILE* input;
  FILE* output;
  
  input = fopen("input.hex", "r");
  output = fopen("output.hex", "w");
  rle_encode(input, output);
  return 0;
}