r_strinstr.c
上传用户:romrleung
上传日期:2022-05-23
资源大小:18897k
文件大小:2k
- /* Copyright (C) 2000 MySQL AB
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
- (at your option) any later version.
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
- /*
- Author : David
- strintstr(src, from, pat) looks for an instance of pat in src
- backwards from pos from. pat is not a regex(3) pattern, it is a literal
- string which must be matched exactly.
- The result 0 if the pattern was not found else it is the start char of
- the pattern counted from the begining of the string.
- */
- #include <my_global.h>
- #include "m_string.h"
- uint r_strinstr(reg1 my_string str,int from, reg4 my_string search)
- {
- reg2 my_string i, j;
- uint len = (uint) strlen(search);
- /* pointer to the last char of buff */
- my_string start = str + from - 1;
- /* pointer to the last char of search */
- my_string search_end = search + len - 1;
- skip:
- while (start >= str) /* Cant be != because the first char */
- {
- if (*start-- == *search_end)
- {
- i = start; j = search_end - 1;
- while (j >= search && start > str)
- if (*i-- != *j--)
- goto skip;
- return (uint) ((start - len) - str + 3);
- }
- }
- return (0);
- }