Hexdump, useful to debug C code. From ##c irc channel

hexdump.c

/* HEXDUMP */
#include <stddef.h>
#include <stdio.h>
#include <ctype.h>


void hexdump(const void * memory, size_t bytes) {
  const unsigned char * p, * q;
  int i;

  p = memory;
  while (bytes) {
    q = p;
    printf("%p: ", (void *) p);
    for (i = 0; i < 16 && bytes; ++i) {
      printf("%02X ", *p);
      ++p;
      --bytes;
    }
    bytes += i;
    while (i < 16) {
      printf("XX ");
      ++i;
    }
    printf("| ");
    p = q;
    for (i = 0; i < 16 && bytes; ++i) {
      printf("%c", isprint(*p) && !isspace(*p) ? *p : ' ');
      ++p;
      --bytes;
    }
    while (i < 16) {
      printf(" ");
      ++i;
    }
    printf(" |\n");
  }
  return;
}