path: root/lib/strlcat.c

/*
 * Copyright (c) 2011 Apple, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */

#include <strings.h>

size_t
strlcat(char * restrict dst, const char * restrict src, size_t maxlen) {
    const size_t srclen = strlen(src);
    const size_t dstlen = strnlen(dst, maxlen);
    if (dstlen == maxlen) return maxlen+srclen;
    if (srclen < maxlen-dstlen) {
        memcpy(dst+dstlen, src, srclen+1);
    } else {
        memcpy(dst+dstlen, src, maxlen-1);
        dst[dstlen+maxlen-1] = '\0';
    }
    return dstlen + srclen;
}