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