8ff97f6210
ctc W544: ["serial/serial.c" 284/3] unreachable code ctc W544: ["vfs/fs_lseek.c" 96/13] unreachable code ctc W544: ["wqueue/kwork_thread.c" 210/32] unreachable code ctc W544: ["stdio/lib_fopen.c" 327/19] unreachable code ctc W544: ["stdio/lib_fopen.c" 404/13] unreachable code ctc W544: ["string/lib_strcasestr.c" 120/3] unreachable code ctc W544: ["unistd/lib_getopt_common.c" 156/21] unreachable code ctc W544: ["unistd/lib_getopt_common.c" 216/21] unreachable code ctc W544: ["wctype/lib_iswctype.c" 155/3] unreachable code Signed-off-by: chao an <anchao@lixiang.com>
122 lines
3.5 KiB
C
122 lines
3.5 KiB
C
/****************************************************************************
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* libs/libc/string/lib_strcasestr.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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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 <strings.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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#undef strcasechr /* See mm/README.txt */
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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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for (; *s != '\0'; 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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return NULL;
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}
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/****************************************************************************
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* Public 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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FAR 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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size_t 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 (FAR 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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break;
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}
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/* Check if this is the beginning of a matching substring
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* (ignoring case)
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*/
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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 (FAR 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. Others might
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* complain about this code being unreachable too.
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*/
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return NULL;
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}
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