nuttx/libs/libc/string/lib_strchrnul.c
Juha Niskanen a17bfec43d libc/string: simplify strrchr
Do not call strlen() here. Old implementation iterated
over string twice, if searched for position was at the
beginning. This commit changes strrchr() to scan string
only once, regardless of input.

Signed-off-by: Juha Niskanen <juha.niskanen@haltian.com>
2022-05-10 23:29:23 +08:00

59 lines
2.0 KiB
C

/****************************************************************************
* libs/libc/string/lib_strchrnul.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 <string.h>
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: strchrnul
*
* Description:
* The strchrnul() function locates the first occurrence of 'c' (converted
* to a char) in the string pointed to by 's'. The terminating null byte is
* considered to be part of the string.
*
* Returned Value:
* Upon completion, strchrnul() returns a pointer to the byte, or a
* pointer to null if the byte was not found.
*
****************************************************************************/
FAR char *strchrnul(FAR const char *s, int c)
{
if (s)
{
while (*s && *s != c)
{
s++;
}
}
return (FAR char *)s;
}