ubgpsuite/lonetix/strncpyz.c

// SPDX-License-Identifier: LGPL-3.0-or-later

/**
 * \file strncpyz.c
 *
 * Implements `Df_strncpyz()`.
 *
 * \copyright The DoubleFourteen Code Forge (C) All Rights Reserved
 * \author    Lorenzo Cogotti
 */

// THIS CODE IS DERIVED FROM OpenBSD strlcpy.c
// ORIGINAL LICENSE TERMS FOLLOW:

/* $OpenBSD: strlcpy.c,v 1.12 2015/01/15 03:54:12 millert Exp $ */

/*
 * Copyright (c) 1998, 2015 Todd C. Miller <Todd.Miller@courtesan.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

// ORIGINAL LICENSE TERMS END ***

#include "strlib.h"

size_t Df_strncpyz(char *dst, const char *src, size_t n)
{
	const char *osrc = src;
	size_t nleft     = n;

	// Copy as many bytes as will fit
	if (nleft > 0) {
		while (--nleft != 0) {
			if ((*dst++ = *src++) == '\0')
				break;
		}
	}

	// Not enough room in dst, add NUL and traverse rest of src
	if (nleft == 0) {
		if (n > 0)
			*dst = '\0';  // NUL-terminate dst

		while (*src++ != '\0');
	}

	return src - osrc - 1;  // count does not include NUL
}