#include <string.h>

int memcmp(const void * a_ptr, const void * b_ptr, size_t size) {
  const unsigned char * a = (const unsigned char *) a_ptr;
  const unsigned char * b = (const unsigned char *) b_ptr;

  for(size_t i = 0; i < size; i++) {
    if(a[i] < b[i]) {
      return -1;
    }
    else if(a[i] > b[i]) {
      return 1;
    }
  }

  return 0;
}