1 /* Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.
2
3 This program is free software; you can redistribute it and/or modify
4 it under the terms of the GNU General Public License, version 2.0,
5 as published by the Free Software Foundation.
6
7 This program is also distributed with certain software (including
8 but not limited to OpenSSL) that is licensed under separate terms,
9 as designated in a particular file or component or in included license
10 documentation. The authors of MySQL hereby grant you an additional
11 permission to link the program and your derivative works with the
12 separately licensed software that they have included with MySQL.
13
14 Without limiting anything contained in the foregoing, this file,
15 which is part of C Driver for MySQL (Connector/C), is also subject to the
16 Universal FOSS Exception, version 1.0, a copy of which can be found at
17 http://oss.oracle.com/licenses/universal-foss-exception.
18
19 This program is distributed in the hope that it will be useful,
20 but WITHOUT ANY WARRANTY; without even the implied warranty of
21 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 GNU General Public License, version 2.0, for more details.
23
24 You should have received a copy of the GNU General Public License
25 along with this program; if not, write to the Free Software
26 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
27
28 /**
29 @file mysys/mf_wcomp.cc
30 Functions for comparing with wild-cards.
31 */
32 #include "mf_wcomp.h"
33
34 #include "my_dbug.h"
35
36 /*
37 This function is different from the wildcmp function of collations.
38 1. This function doesn't guard it from stack overrun.
39 2. This function is not aware of charset.
40 3. This function's expression string can be considered as pattern. Please
41 refer to the declaration.
42 */
wild_compare_full(const char * str,int strlen,const char * wildstr,int wildlen,bool str_is_pattern,char w_prefix,char w_one,char w_many)43 int wild_compare_full(const char *str, int strlen, const char *wildstr,
44 int wildlen, bool str_is_pattern, char w_prefix,
45 char w_one, char w_many) {
46 const char *strend = str + strlen;
47 const char *wildend = wildstr + wildlen;
48 char cmp;
49 DBUG_TRACE;
50
51 while (wildstr < wildend) {
52 /*
53 Loop through expression string (str) and pattern string (wildstr) byte by
54 byte until they are different, or we find a wildcard char (w_many or
55 w_one) in pattern string.
56 */
57 while (wildstr < wildend && *wildstr != w_many && *wildstr != w_one) {
58 if (*wildstr == w_prefix && wildstr + 1 < wildend) {
59 wildstr++;
60 /*
61 If there is a escape char in pattern string, and expression string can
62 be considered as pattern, there should be a escape char in input
63 string too.
64 */
65 if (str_is_pattern && str < strend && *str++ != w_prefix) return 1;
66 }
67 if (str == strend || *wildstr++ != *str++) return 1;
68 }
69 if (wildstr == wildend) return str < strend;
70 /*
71 Skip one char if wildcard is w_one. If expression string can be
72 considered as pattern, any char in expression string except of w_many can
73 be skipped.
74 */
75 if (*wildstr++ == w_one) {
76 if (str == strend || (str_is_pattern && *str == w_many))
77 return 1; /* One char; skip */
78 if (*str++ == w_prefix && str_is_pattern) str++;
79 } else { /* Found '*' */
80 /*
81 If wildcard char is w_many, then we skip any wildcard char following
82 it.
83 */
84 while (str_is_pattern && str < strend && *str == w_many) str++;
85 for (; wildstr < wildend && (*wildstr == w_many || *wildstr == w_one);
86 wildstr++) {
87 if (*wildstr == w_many) {
88 while (str_is_pattern && str < strend && *str == w_many) str++;
89 } else {
90 if (str_is_pattern && str + 1 < strend && *str == w_prefix)
91 str += 2;
92 else if (str == strend)
93 return 1;
94 }
95 }
96 if (wildstr == wildend) return 0; /* '*' as last char: OK */
97 if ((cmp = *wildstr) == w_prefix && wildstr + 1 < wildend &&
98 !str_is_pattern)
99 cmp = wildstr[1];
100 // cmp is the character following w_many.
101 for (;; str++) {
102 /*
103 Skip until we find a character in the expression string that is
104 equal to cmp. For the character not equal to cmp, we consider they are
105 all matched by w_many.
106 */
107 while (str < strend && *str != cmp) str++;
108 if (str == strend) return 1;
109 // Recursively call ourselves until we find a match.
110 if (wild_compare_full(str, strend - str, wildstr, wildend - wildstr,
111 str_is_pattern, w_prefix, w_one, w_many) == 0)
112 return 0;
113 }
114 /* We will never come here */
115 }
116 }
117 return str < strend;
118 } /* wild_compare */
119
wild_compare(const char * str,int strlen,const char * wildstr,int wildlen,bool str_is_pattern)120 int wild_compare(const char *str, int strlen, const char *wildstr, int wildlen,
121 bool str_is_pattern) {
122 return wild_compare_full(str, strlen, wildstr, wildlen, str_is_pattern,
123 wild_prefix, wild_one, wild_many);
124 }
125