incubator-nuttx/libs/libc/string/lib_strlcat.c

90 lines
2.5 KiB
C

/****************************************************************************
* libs/libc/string/lib_strlcat.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <string.h>
#include "libc.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: strlcat
*
* Description:
* The strlcat() function appends at most (dstsize-strlen(dst)-1)
* characters of src to dst (dstsize being the size of the string buffer
* dst).
*
* Returned Value:
* Returns min{dstsize,strlen(dst)} + strlen(src).
*
****************************************************************************/
#if !defined(CONFIG_LIBC_ARCH_STRLCAT) && defined(LIBC_BUILD_STRING)
size_t strlcat(FAR char *dst, FAR const char *src, size_t dsize)
{
FAR const char *odst = dst;
FAR const char *osrc = src;
size_t n = dsize;
size_t dlen;
/* Find the end of dst and adjust bytes left but don't go past end. */
while (n-- != 0 && *dst != '\0')
{
dst++;
}
dlen = dst - odst;
n = dsize - dlen;
if (n-- == 0)
{
return dlen + strlen(src);
}
while (*src != '\0')
{
if (n != 0)
{
*dst++ = *src;
n--;
}
src++;
}
*dst = '\0';
/* Count does not include NUL */
return dlen + (src - osrc);
}
#endif