/* CC0 license (public domain) - see LICENSE file for details */

#include <config.h>

#include <hex.h>

#include <stdio.h>

#include <stdlib.h>

static bool char_to_hex(unsigned char *val, char c)

{

	if (c >= '0' && c <= '9') {

		*val = c - '0';

		return true;

	}

	if (c >= 'a' && c <= 'f') {

		*val = c - 'a' + 10;

		return true;

	}

	if (c >= 'A' && c <= 'F') {

		*val = c - 'A' + 10;

		return true;

	}

	return false;

}

bool hex_decode(const char *str, size_t slen, void *buf, size_t bufsize)

{

	unsigned char v1, v2;

	unsigned char *p = buf;

	while (slen > 1) {

		if (!char_to_hex(&v1, str[0]) || !char_to_hex(&v2, str[1]))

			return false;

		if (!bufsize)

			return false;

		*(p++) = (v1 << 4) | v2;

		str += 2;

		slen -= 2;

		bufsize--;

	}

	return slen == 0 && bufsize == 0;

}

static char hexchar(unsigned int val)

{

	if (val < 10)

		return '0' + val;

	if (val < 16)

		return 'a' + val - 10;

	abort();

}

bool hex_encode(const void *buf, size_t bufsize, char *dest, size_t destsize)

{

	size_t used = 0;

	if (destsize < 1)

		return false;

	while (used < bufsize) {

		unsigned int c = ((const unsigned char *)buf)[used];

		if (destsize < 3)

			return false;

		*(dest++) = hexchar(c >> 4);

		*(dest++) = hexchar(c & 0xF);

		used++;

		destsize -= 2;

	}

	*dest = '\0';

	return used + 1;

}