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Diffstat (limited to 'nuttx/lib/string/lib_memchr.c')
-rw-r--r-- | nuttx/lib/string/lib_memchr.c | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/nuttx/lib/string/lib_memchr.c b/nuttx/lib/string/lib_memchr.c new file mode 100644 index 000000000..e0dec8270 --- /dev/null +++ b/nuttx/lib/string/lib_memchr.c @@ -0,0 +1,80 @@ +/**************************************************************************** + * lib/string/lib_memchr.c + * + * Copyright (C) 2012 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <gnutt@nuttx.org> + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * 3. Neither the name NuttX nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS + * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED + * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> + +#include <string.h> + +/**************************************************************************** + * Global Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: memchr + * + * Description: + * The memchr() function locates the first occurrence of 'c' (converted to + * an unsigned char) in the initial 'n' bytes (each interpreted as + * unsigned char) of the object pointed to by s. + * + * Returned Value: + * The memchr() function returns a pointer to the located byte, or a null + * pointer if the byte does not occur in the object. + * + ****************************************************************************/ + +FAR void *memchr(FAR const void *s, int c, size_t n) +{ + FAR const unsigned char *p = (FAR const unsigned char *)s; + + if (s) + { + while (n--) + { + if (*p == (unsigned char)c) + { + return (FAR void *)p; + } + + p++; + } + } + + return NULL; +} |