1 /* Optimized string comparison.
2 Copyright (C) 2001-2002, 2007, 2009-2023 Free Software Foundation, Inc.
3
4 This file is free software: you can redistribute it and/or modify
5 it under the terms of the GNU Lesser General Public License as
6 published by the Free Software Foundation; either version 2.1 of the
7 License, or (at your option) any later version.
8
9 This file is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public License
15 along with this program. If not, see <https://www.gnu.org/licenses/>. */
16
17 /* Written by Bruno Haible <bruno@clisp.org>. */
18
19 #ifndef _GL_STREQ_H
20 #define _GL_STREQ_H
21
22 #include <string.h>
23
24 /* STREQ_OPT allows to optimize string comparison with a small literal string.
25 STREQ_OPT (s, "EUC-KR", 'E', 'U', 'C', '-', 'K', 'R', 0, 0, 0)
26 is semantically equivalent to
27 strcmp (s, "EUC-KR") == 0
28 just faster. */
29
30 /* Help GCC to generate good code for string comparisons with
31 immediate strings. */
32 #if (defined __GNUC__ || defined __clang__) && defined __OPTIMIZE__
33
34 static inline int
35 streq9 (const char *s1, const char *s2)
36 {
37 return strcmp (s1 + 9, s2 + 9) == 0;
38 }
39
40 static inline int
41 streq8 (const char *s1, const char *s2, char s28)
42 {
43 if (s1[8] == s28)
44 {
45 if (s28 == 0)
46 return 1;
47 else
48 return streq9 (s1, s2);
49 }
50 else
51 return 0;
52 }
53
54 static inline int
55 streq7 (const char *s1, const char *s2, char s27, char s28)
56 {
57 if (s1[7] == s27)
58 {
59 if (s27 == 0)
60 return 1;
61 else
62 return streq8 (s1, s2, s28);
63 }
64 else
65 return 0;
66 }
67
68 static inline int
69 streq6 (const char *s1, const char *s2, char s26, char s27, char s28)
70 {
71 if (s1[6] == s26)
72 {
73 if (s26 == 0)
74 return 1;
75 else
76 return streq7 (s1, s2, s27, s28);
77 }
78 else
79 return 0;
80 }
81
82 static inline int
83 streq5 (const char *s1, const char *s2, char s25, char s26, char s27, char s28)
84 {
85 if (s1[5] == s25)
86 {
87 if (s25 == 0)
88 return 1;
89 else
90 return streq6 (s1, s2, s26, s27, s28);
91 }
92 else
93 return 0;
94 }
95
96 static inline int
97 streq4 (const char *s1, const char *s2, char s24, char s25, char s26, char s27, char s28)
98 {
99 if (s1[4] == s24)
100 {
101 if (s24 == 0)
102 return 1;
103 else
104 return streq5 (s1, s2, s25, s26, s27, s28);
105 }
106 else
107 return 0;
108 }
109
110 static inline int
111 streq3 (const char *s1, const char *s2, char s23, char s24, char s25, char s26, char s27, char s28)
112 {
113 if (s1[3] == s23)
114 {
115 if (s23 == 0)
116 return 1;
117 else
118 return streq4 (s1, s2, s24, s25, s26, s27, s28);
119 }
120 else
121 return 0;
122 }
123
124 static inline int
125 streq2 (const char *s1, const char *s2, char s22, char s23, char s24, char s25, char s26, char s27, char s28)
126 {
127 if (s1[2] == s22)
128 {
129 if (s22 == 0)
130 return 1;
131 else
132 return streq3 (s1, s2, s23, s24, s25, s26, s27, s28);
133 }
134 else
135 return 0;
136 }
137
138 static inline int
139 streq1 (const char *s1, const char *s2, char s21, char s22, char s23, char s24, char s25, char s26, char s27, char s28)
140 {
141 if (s1[1] == s21)
142 {
143 if (s21 == 0)
144 return 1;
145 else
146 return streq2 (s1, s2, s22, s23, s24, s25, s26, s27, s28);
147 }
148 else
149 return 0;
150 }
151
152 static inline int
153 streq0 (const char *s1, const char *s2, char s20, char s21, char s22, char s23, char s24, char s25, char s26, char s27, char s28)
154 {
155 if (s1[0] == s20)
156 {
157 if (s20 == 0)
158 return 1;
159 else
160 return streq1 (s1, s2, s21, s22, s23, s24, s25, s26, s27, s28);
161 }
162 else
163 return 0;
164 }
165
166 #define STREQ_OPT(s1,s2,s20,s21,s22,s23,s24,s25,s26,s27,s28) \
167 streq0 (s1, s2, s20, s21, s22, s23, s24, s25, s26, s27, s28)
168
169 #else
170
171 #define STREQ_OPT(s1,s2,s20,s21,s22,s23,s24,s25,s26,s27,s28) \
172 (strcmp (s1, s2) == 0)
173
174 #endif
175
176 #endif /* _GL_STREQ_H */