lib/c-strcaseeq.h

   1 /* Optimized case-insensitive string comparison in C locale.
   2    Copyright (C) 2001-2002, 2007, 2009-2024 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 #include "c-strcase.h"
  20 #include "c-ctype.h"
  21
  22 #ifdef __cplusplus
  23 extern "C" {
  24 #endif
  25
  26
  27 /* STRCASEEQ allows to optimize string comparison with a small literal string.
  28      STRCASEEQ (s, "UTF-8", 'U','T','F','-','8',0,0,0,0)
  29    is semantically equivalent to
  30      c_strcasecmp (s, "UTF-8") == 0
  31    just faster.  */
  32
  33 /* Help GCC to generate good code for string comparisons with
  34    immediate strings. */
  35 #if (defined __GNUC__ || defined __clang__) && defined __OPTIMIZE__
  36
  37 /* Case insensitive comparison of ASCII characters.  */
  38 # if C_CTYPE_ASCII
  39 #  define CASEEQ(other,upper) \
  40      (c_isupper (upper) ? ((other) & ~0x20) == (upper) : (other) == (upper))
  41 # else
  42 #  define CASEEQ(other,upper) \
  43      (c_toupper (other) == (upper))
  44 # endif
  45
  46 static inline int
  47 strcaseeq9 (const char *s1, const char *s2)
  48 {
  49   return c_strcasecmp (s1 + 9, s2 + 9) == 0;
  50 }
  51
  52 static inline int
  53 strcaseeq8 (const char *s1, const char *s2, char s28)
  54 {
  55   if (CASEEQ (s1[8], s28))
  56     {
  57       if (s28 == 0)
  58         return 1;
  59       else
  60         return strcaseeq9 (s1, s2);
  61     }
  62   else
  63     return 0;
  64 }
  65
  66 static inline int
  67 strcaseeq7 (const char *s1, const char *s2, char s27, char s28)
  68 {
  69   if (CASEEQ (s1[7], s27))
  70     {
  71       if (s27 == 0)
  72         return 1;
  73       else
  74         return strcaseeq8 (s1, s2, s28);
  75     }
  76   else
  77     return 0;
  78 }
  79
  80 static inline int
  81 strcaseeq6 (const char *s1, const char *s2, char s26, char s27, char s28)
  82 {
  83   if (CASEEQ (s1[6], s26))
  84     {
  85       if (s26 == 0)
  86         return 1;
  87       else
  88         return strcaseeq7 (s1, s2, s27, s28);
  89     }
  90   else
  91     return 0;
  92 }
  93
  94 static inline int
  95 strcaseeq5 (const char *s1, const char *s2, char s25, char s26, char s27, char s28)
  96 {
  97   if (CASEEQ (s1[5], s25))
  98     {
  99       if (s25 == 0)
 100         return 1;
 101       else
 102         return strcaseeq6 (s1, s2, s26, s27, s28);
 103     }
 104   else
 105     return 0;
 106 }
 107
 108 static inline int
 109 strcaseeq4 (const char *s1, const char *s2, char s24, char s25, char s26, char s27, char s28)
 110 {
 111   if (CASEEQ (s1[4], s24))
 112     {
 113       if (s24 == 0)
 114         return 1;
 115       else
 116         return strcaseeq5 (s1, s2, s25, s26, s27, s28);
 117     }
 118   else
 119     return 0;
 120 }
 121
 122 static inline int
 123 strcaseeq3 (const char *s1, const char *s2, char s23, char s24, char s25, char s26, char s27, char s28)
 124 {
 125   if (CASEEQ (s1[3], s23))
 126     {
 127       if (s23 == 0)
 128         return 1;
 129       else
 130         return strcaseeq4 (s1, s2, s24, s25, s26, s27, s28);
 131     }
 132   else
 133     return 0;
 134 }
 135
 136 static inline int
 137 strcaseeq2 (const char *s1, const char *s2, char s22, char s23, char s24, char s25, char s26, char s27, char s28)
 138 {
 139   if (CASEEQ (s1[2], s22))
 140     {
 141       if (s22 == 0)
 142         return 1;
 143       else
 144         return strcaseeq3 (s1, s2, s23, s24, s25, s26, s27, s28);
 145     }
 146   else
 147     return 0;
 148 }
 149
 150 static inline int
 151 strcaseeq1 (const char *s1, const char *s2, char s21, char s22, char s23, char s24, char s25, char s26, char s27, char s28)
 152 {
 153   if (CASEEQ (s1[1], s21))
 154     {
 155       if (s21 == 0)
 156         return 1;
 157       else
 158         return strcaseeq2 (s1, s2, s22, s23, s24, s25, s26, s27, s28);
 159     }
 160   else
 161     return 0;
 162 }
 163
 164 static inline int
 165 strcaseeq0 (const char *s1, const char *s2, char s20, char s21, char s22, char s23, char s24, char s25, char s26, char s27, char s28)
 166 {
 167   if (CASEEQ (s1[0], s20))
 168     {
 169       if (s20 == 0)
 170         return 1;
 171       else
 172         return strcaseeq1 (s1, s2, s21, s22, s23, s24, s25, s26, s27, s28);
 173     }
 174   else
 175     return 0;
 176 }
 177
 178 #define STRCASEEQ(s1,s2,s20,s21,s22,s23,s24,s25,s26,s27,s28) \
 179   strcaseeq0 (s1, s2, s20, s21, s22, s23, s24, s25, s26, s27, s28)
 180
 181 #else
 182
 183 #define STRCASEEQ(s1,s2,s20,s21,s22,s23,s24,s25,s26,s27,s28) \
 184   (c_strcasecmp (s1, s2) == 0)
 185
 186 #endif
 187
 188
 189 #ifdef __cplusplus
 190 }
 191 #endif