/*

 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/.

 *

 * See the COPYRIGHT file distributed with this work for additional

 * information regarding copyright ownership.

 */

/*! \file */

#include <config.h>

#include <stdbool.h>

#include <isc/safe.h>

#include <isc/string.h>

#include <isc/util.h>

#ifdef WIN32

#include <windows.h>

#endif

#ifdef _MSC_VER

#pragma optimize("", off)

#endif

bool

isc_safe_memequal(const void *s1, const void *s2, size_t n) {

	uint8_t acc = 0;

	if (n != 0U) {

		const uint8_t *p1 = s1, *p2 = s2;

		do {

			acc |= *p1++ ^ *p2++;

		} while (--n != 0U);

	}

	return (acc == 0);

}

int

isc_safe_memcompare(const void *b1, const void *b2, size_t len) {

	const unsigned char *p1 = b1, *p2 = b2;

	size_t i;

	int res = 0, done = 0;

	for (i = 0; i < len; i++) {

		/* lt is -1 if p1[i] < p2[i]; else 0. */

		int lt = (p1[i] - p2[i]) >> CHAR_BIT;

		/* gt is -1 if p1[i] > p2[i]; else 0. */

		int gt = (p2[i] - p1[i]) >> CHAR_BIT;

		/* cmp is 1 if p1[i] > p2[i]; -1 if p1[i] < p2[i]; else 0. */

		int cmp = lt - gt;

		/* set res = cmp if !done. */

		res |= cmp & ~done;

		/* set done if p1[i] != p2[i]. */

		done |= lt | gt;

	}

	return (res);

}

void

isc_safe_memwipe(void *ptr, size_t len) {

	if (ISC_UNLIKELY(ptr == NULL || len == 0))

		return;

#ifdef WIN32

	SecureZeroMemory(ptr, len);

#elif HAVE_EXPLICIT_BZERO

	explicit_bzero(ptr, len);

#else

	memset(ptr, 0, len);

#endif

}