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Diffstat (limited to 'lib/streq.h')
| -rw-r--r-- | lib/streq.h | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/lib/streq.h b/lib/streq.h new file mode 100644 index 0000000..49f73c1 --- /dev/null +++ b/lib/streq.h @@ -0,0 +1,176 @@ +/* Optimized string comparison. + Copyright (C) 2001-2002, 2007, 2009-2022 Free Software Foundation, Inc. + + This file is free software: you can redistribute it and/or modify + it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of the + License, or (at your option) any later version. + + This file 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 Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +/* Written by Bruno Haible <bruno@clisp.org>. */ + +#ifndef _GL_STREQ_H +#define _GL_STREQ_H + +#include <string.h> + +/* STREQ_OPT allows to optimize string comparison with a small literal string. + STREQ_OPT (s, "EUC-KR", 'E', 'U', 'C', '-', 'K', 'R', 0, 0, 0) + is semantically equivalent to + strcmp (s, "EUC-KR") == 0 + just faster. */ + +/* Help GCC to generate good code for string comparisons with + immediate strings. */ +#if (defined __GNUC__ || defined __clang__) && defined __OPTIMIZE__ + +static inline int +streq9 (const char *s1, const char *s2) +{ + return strcmp (s1 + 9, s2 + 9) == 0; +} + +static inline int +streq8 (const char *s1, const char *s2, char s28) +{ + if (s1[8] == s28) + { + if (s28 == 0) + return 1; + else + return streq9 (s1, s2); + } + else + return 0; +} + +static inline int +streq7 (const char *s1, const char *s2, char s27, char s28) +{ + if (s1[7] == s27) + { + if (s27 == 0) + return 1; + else + return streq8 (s1, s2, s28); + } + else + return 0; +} + +static inline int +streq6 (const char *s1, const char *s2, char s26, char s27, char s28) +{ + if (s1[6] == s26) + { + if (s26 == 0) + return 1; + else + return streq7 (s1, s2, s27, s28); + } + else + return 0; +} + +static inline int +streq5 (const char *s1, const char *s2, char s25, char s26, char s27, char s28) +{ + if (s1[5] == s25) + { + if (s25 == 0) + return 1; + else + return streq6 (s1, s2, s26, s27, s28); + } + else + return 0; +} + +static inline int +streq4 (const char *s1, const char *s2, char s24, char s25, char s26, char s27, char s28) +{ + if (s1[4] == s24) + { + if (s24 == 0) + return 1; + else + return streq5 (s1, s2, s25, s26, s27, s28); + } + else + return 0; +} + +static inline int +streq3 (const char *s1, const char *s2, char s23, char s24, char s25, char s26, char s27, char s28) +{ + if (s1[3] == s23) + { + if (s23 == 0) + return 1; + else + return streq4 (s1, s2, s24, s25, s26, s27, s28); + } + else + return 0; +} + +static inline int +streq2 (const char *s1, const char *s2, char s22, char s23, char s24, char s25, char s26, char s27, char s28) +{ + if (s1[2] == s22) + { + if (s22 == 0) + return 1; + else + return streq3 (s1, s2, s23, s24, s25, s26, s27, s28); + } + else + return 0; +} + +static inline int +streq1 (const char *s1, const char *s2, char s21, char s22, char s23, char s24, char s25, char s26, char s27, char s28) +{ + if (s1[1] == s21) + { + if (s21 == 0) + return 1; + else + return streq2 (s1, s2, s22, s23, s24, s25, s26, s27, s28); + } + else + return 0; +} + +static inline int +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) +{ + if (s1[0] == s20) + { + if (s20 == 0) + return 1; + else + return streq1 (s1, s2, s21, s22, s23, s24, s25, s26, s27, s28); + } + else + return 0; +} + +#define STREQ_OPT(s1,s2,s20,s21,s22,s23,s24,s25,s26,s27,s28) \ + streq0 (s1, s2, s20, s21, s22, s23, s24, s25, s26, s27, s28) + +#else + +#define STREQ_OPT(s1,s2,s20,s21,s22,s23,s24,s25,s26,s27,s28) \ + (strcmp (s1, s2) == 0) + +#endif + +#endif /* _GL_STREQ_H */ |