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git-svn-id: https://nuttx.svn.sourceforge.net/svnroot/nuttx/trunk@4364 7fd9a85b-ad96-42d3-883c-3090e2eb8679sbg
patacongo
13 years ago
6 changed files with 170 additions and 41 deletions
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/****************************************************************************
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* lib/string/lib_strstr.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 str 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 str binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer str |
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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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#include <ctype.h> |
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/****************************************************************************
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* Private Functions |
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****************************************************************************/ |
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static FAR char *strcasechr(FAR const char *s, int uc) |
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{ |
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register char ch; |
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if (s) |
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{ |
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for (; *s; s++) |
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{ |
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ch = *s; |
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if (toupper(ch) == uc) |
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{ |
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return (FAR char*)s; |
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} |
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} |
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} |
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return NULL; |
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} |
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/****************************************************************************
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* Global Functions |
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****************************************************************************/ |
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FAR char *strcasestr(FAR const char *str, FAR const char *substr) |
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{ |
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const char *candidate; /* Candidate in str with matching start character */ |
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char ch; /* First character of the substring */ |
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int len; /* The length of the substring */ |
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/* Special case the empty substring */ |
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len = strlen(substr); |
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ch = *substr; |
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if (!ch) |
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{ |
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/* We'll say that an empty substring matches at the beginning of
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* the string |
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*/ |
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return (char*)str; |
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} |
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/* Search for the substring */ |
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candidate = str; |
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ch = toupper(ch); |
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for (;;) |
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{ |
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/* strcasechr() will return a pointer to the next occurrence of the
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* character ch in the string (ignoring case) |
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*/ |
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candidate = strcasechr(candidate, ch); |
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if (!candidate || strlen(candidate) < len) |
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{ |
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/* First character of the substring does not appear in the string
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* or the remainder of the string is not long enough to contain the |
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* substring. |
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*/ |
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return NULL; |
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} |
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/* Check if this is the beginning of a matching substring (ignoring case) */ |
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if (strncasecmp(candidate, substr, len) == 0) |
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{ |
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/* Yes.. return the pointer to the first occurrence of the matching
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* substring. |
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*/ |
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return (char*)candidate; |
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} |
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/* No, find the next candidate after this one */ |
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candidate++; |
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} |
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/* Won't get here, but some compilers might complain */ |
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return NULL; |
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} |
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