/* LICENSE: BSD 2-Clause */

#include <stdio.h>

static int __dump_buf(const void *buf, size_t len,
		      int (*dump_char)(unsigned char), int bytes_per_line)
{
	size_t i;
	const unsigned char *ptr = buf;

	for (i = 0; i < len; i++) {
		if (!(i % bytes_per_line))
			if (printf("0x%04zx: ", i) < 0)
				return -1;

		if (dump_char(ptr[i]) == -1)
			return -1;

		if (putchar((i + 1) % bytes_per_line && i + 1 < len
				? ' ' : '\n') == EOF)
			return -1;
	}

	return 0;
}

int hex_dump_char(unsigned char c)
{
	if (printf("%02x", c) < 0)
		return -1;

	return 0;
}

int bin_dump_char(unsigned char c)
{
	unsigned char bit_mask;

	for (bit_mask = 0x80; bit_mask; bit_mask = bit_mask >> 1)
		if (putchar(c & bit_mask ? '1' : '0') == EOF)
			return -1;

	return 0;
}

int hex_dump(const void *buf, size_t len)
{
	return __dump_buf(buf, len, hex_dump_char, 16);
}

int bin_dump(const void *buf, size_t len)
{
	return __dump_buf(buf, len, bin_dump_char, 8);
}

int main()
{
	size_t i;
	char buf[32];

	for (i = 0; i < sizeof(buf); i++)
		buf[i] = i;

	if (hex_dump(buf, sizeof(buf)) == -1)
		return 1;

	if (bin_dump(buf, sizeof(buf)) == -1)
		return 1;

	return 0;
}