libguile/strorder.c

   1 /*      Copyright (C) 1995, 1996, 1999, 2000 Free Software Foundation, Inc.
   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 as published by
   5  * the Free Software Foundation; either version 2, or (at your option)
   6  * any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this software; see the file COPYING.  If not, write to
  15  * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  16  * Boston, MA 02111-1307 USA
  17  *
  18  * As a special exception, the Free Software Foundation gives permission
  19  * for additional uses of the text contained in its release of GUILE.
  20  *
  21  * The exception is that, if you link the GUILE library with other files
  22  * to produce an executable, this does not by itself cause the
  23  * resulting executable to be covered by the GNU General Public License.
  24  * Your use of that executable is in no way restricted on account of
  25  * linking the GUILE library code into it.
  26  *
  27  * This exception does not however invalidate any other reasons why
  28  * the executable file might be covered by the GNU General Public License.
  29  *
  30  * This exception applies only to the code released by the
  31  * Free Software Foundation under the name GUILE.  If you copy
  32  * code from other Free Software Foundation releases into a copy of
  33  * GUILE, as the General Public License permits, the exception does
  34  * not apply to the code that you add in this way.  To avoid misleading
  35  * anyone as to the status of such modified files, you must delete
  36  * this exception notice from them.
  37  *
  38  * If you write modifications of your own for GUILE, it is your choice
  39  * whether to permit this exception to apply to your modifications.
  40  * If you do not wish that, delete this exception notice.  */
  41
  42 /* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
  43    gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */
  44 \f
  45
  46 #include "libguile/_scm.h"
  47 #include "libguile/chars.h"
  48 #include "libguile/strings.h"
  49 #include "libguile/symbols.h"
  50
  51 #include "libguile/validate.h"
  52 #include "libguile/strorder.h"
  53 \f
  54
  55 SCM_DEFINE1 (scm_string_equal_p, "string=?", scm_tc7_rpsubr,
  56              (SCM s1, SCM s2),
  57             "Lexicographic equality predicate; return @code{#t} if the two\n"
  58             "strings are the same length and contain the same characters in\n"
  59             "the same positions, otherwise return @code{#f}.\n"
  60             "\n"
  61             "The procedure @code{string-ci=?} treats upper and lower case\n"
  62             "letters as though they were the same character, but\n"
  63             "@code{string=?} treats upper and lower case as distinct\n"
  64             "characters.")
  65 #define FUNC_NAME s_scm_string_equal_p
  66 {
  67   scm_sizet length;
  68
  69   SCM_VALIDATE_STRING (1, s1);
  70   SCM_VALIDATE_STRING (2, s2);
  71
  72   length = SCM_STRING_LENGTH (s2);
  73   if (SCM_STRING_LENGTH (s1) == length)
  74     {
  75       unsigned char *c1 = SCM_STRING_UCHARS (s1) + length - 1;
  76       unsigned char *c2 = SCM_STRING_UCHARS (s2) + length - 1;
  77       scm_sizet i;
  78
  79       /* comparing from back to front typically finds mismatches faster */
  80       for (i = 0; i != length; ++i, --c1, --c2)
  81         if (*c1 != *c2)
  82           return SCM_BOOL_F;
  83
  84       return SCM_BOOL_T;
  85     }
  86   else
  87     {
  88       return SCM_BOOL_F;
  89     }
  90 }
  91 #undef FUNC_NAME
  92
  93
  94 SCM_DEFINE1 (scm_string_ci_equal_p, "string-ci=?", scm_tc7_rpsubr,
  95              (SCM s1, SCM s2),
  96             "Case-insensitive string equality predicate; return @code{#t} if\n"
  97             "the two strings are the same length and their component\n"
  98             "characters match (ignoring case) at each position; otherwise\n"
  99             "return @code{#f}.")
 100 #define FUNC_NAME s_scm_string_ci_equal_p
 101 {
 102   scm_sizet length;
 103
 104   SCM_VALIDATE_STRING (1, s1);
 105   SCM_VALIDATE_STRING (2, s2);
 106
 107   length = SCM_STRING_LENGTH (s2);
 108   if (SCM_STRING_LENGTH (s1) == length)
 109     {
 110       unsigned char *c1 = SCM_STRING_UCHARS (s1) + length - 1;
 111       unsigned char *c2 = SCM_STRING_UCHARS (s2) + length - 1;
 112       scm_sizet i;
 113
 114       /* comparing from back to front typically finds mismatches faster */
 115       for (i = 0; i != length; ++i, --c1, --c2)
 116         if (scm_upcase (*c1) != scm_upcase (*c2))
 117           return SCM_BOOL_F;
 118
 119       return SCM_BOOL_T;
 120     }
 121   else
 122     {
 123       return SCM_BOOL_F;
 124     }
 125 }
 126 #undef FUNC_NAME
 127
 128
 129 /* Helper function for the lexicographic ordering predicates.
 130  * No argument checking is performed.  */
 131 static SCM
 132 string_less_p (SCM s1, SCM s2)
 133 {
 134   scm_sizet i, length1, length2, lengthm;
 135   unsigned char *c1, *c2;
 136
 137   length1 = SCM_STRING_LENGTH (s1);
 138   length2 = SCM_STRING_LENGTH (s2);
 139   lengthm = min (length1, length2);
 140   c1 = SCM_STRING_UCHARS (s1);
 141   c2 = SCM_STRING_UCHARS (s2);
 142
 143   for (i = 0; i != lengthm; ++i, ++c1, ++c2) {
 144     int c = *c1 - *c2;
 145     if (c < 0) return SCM_BOOL_T;
 146     if (c > 0) return SCM_BOOL_F;
 147   }
 148
 149   return SCM_BOOL (length1 < length2);
 150 }
 151
 152
 153 SCM_DEFINE1 (scm_string_less_p, "string<?", scm_tc7_rpsubr,
 154              (SCM s1, SCM s2),
 155             "Lexicographic ordering predicate; return @code{#t} if @var{s1}\n"
 156             "is lexicographically less than @var{s2}.")
 157 #define FUNC_NAME s_scm_string_less_p
 158 {
 159   SCM_VALIDATE_STRING (1, s1);
 160   SCM_VALIDATE_STRING (2, s2);
 161
 162   return string_less_p (s1, s2);
 163 }
 164 #undef FUNC_NAME
 165
 166
 167 SCM_DEFINE1 (scm_string_leq_p, "string<=?", scm_tc7_rpsubr,
 168              (SCM s1, SCM s2),
 169             "Lexicographic ordering predicate; return @code{#t} if @var{s1}\n"
 170             "is lexicographically less than or equal to @var{s2}.")
 171 #define FUNC_NAME s_scm_string_leq_p
 172 {
 173   SCM_VALIDATE_STRING (1, s1);
 174   SCM_VALIDATE_STRING (2, s2);
 175
 176   return SCM_BOOL_NOT (string_less_p (s2, s1));
 177 }
 178 #undef FUNC_NAME
 179
 180
 181 SCM_DEFINE1 (scm_string_gr_p, "string>?", scm_tc7_rpsubr,
 182              (SCM s1, SCM s2),
 183             "Lexicographic ordering predicate; return @code{#t} if @var{s1}\n"
 184             "is lexicographically greater than @var{s2}.")
 185 #define FUNC_NAME s_scm_string_gr_p
 186 {
 187   SCM_VALIDATE_STRING (1, s1);
 188   SCM_VALIDATE_STRING (2, s2);
 189
 190   return string_less_p (s2, s1);
 191 }
 192 #undef FUNC_NAME
 193
 194
 195 SCM_DEFINE1 (scm_string_geq_p, "string>=?", scm_tc7_rpsubr,
 196              (SCM s1, SCM s2),
 197             "Lexicographic ordering predicate; return @code{#t} if @var{s1}\n"
 198             "is lexicographically greater than or equal to @var{s2}.")
 199 #define FUNC_NAME s_scm_string_geq_p
 200 {
 201   SCM_VALIDATE_STRING (1, s1);
 202   SCM_VALIDATE_STRING (2, s2);
 203
 204   return SCM_BOOL_NOT (string_less_p (s1, s2));
 205 }
 206 #undef FUNC_NAME
 207
 208
 209 /* Helper function for the case insensitive lexicographic ordering
 210  * predicates.  No argument checking is performed.  */
 211 static SCM
 212 string_ci_less_p (SCM s1, SCM s2)
 213 {
 214   scm_sizet i, length1, length2, lengthm;
 215   unsigned char *c1, *c2;
 216
 217   length1 = SCM_STRING_LENGTH (s1);
 218   length2 = SCM_STRING_LENGTH (s2);
 219   lengthm = min (length1, length2);
 220   c1 = SCM_STRING_UCHARS (s1);
 221   c2 = SCM_STRING_UCHARS (s2);
 222
 223   for (i = 0; i != lengthm; ++i, ++c1, ++c2) {
 224     int c = scm_upcase (*c1) - scm_upcase (*c2);
 225     if (c < 0) return SCM_BOOL_T;
 226     if (c > 0) return SCM_BOOL_F;
 227   }
 228
 229   return SCM_BOOL (length1 < length2);
 230 }
 231
 232
 233 SCM_DEFINE1 (scm_string_ci_less_p, "string-ci<?", scm_tc7_rpsubr,
 234              (SCM s1, SCM s2),
 235             "Case insensitive lexicographic ordering predicate; return\n"
 236             "@code{#t} if @var{s1} is lexicographically less than @var{s2}\n"
 237             "regardless of case.")
 238 #define FUNC_NAME s_scm_string_ci_less_p
 239 {
 240   SCM_VALIDATE_STRING (1, s1);
 241   SCM_VALIDATE_STRING (2, s2);
 242
 243   return string_ci_less_p (s1, s2);
 244 }
 245 #undef FUNC_NAME
 246
 247
 248 SCM_DEFINE1 (scm_string_ci_leq_p, "string-ci<=?", scm_tc7_rpsubr,
 249              (SCM s1, SCM s2),
 250             "Case insensitive lexicographic ordering predicate; return\n"
 251             "@code{#t} if @var{s1} is lexicographically less than or equal\n"
 252             "to @var{s2} regardless of case.")
 253 #define FUNC_NAME s_scm_string_ci_leq_p
 254 {
 255   SCM_VALIDATE_STRING (1, s1);
 256   SCM_VALIDATE_STRING (2, s2);
 257
 258   return SCM_BOOL_NOT (string_ci_less_p (s2, s1));
 259 }
 260 #undef FUNC_NAME
 261
 262
 263 SCM_DEFINE1 (scm_string_ci_gr_p, "string-ci>?", scm_tc7_rpsubr,
 264              (SCM s1, SCM s2),
 265             "Case insensitive lexicographic ordering predicate; return\n"
 266             "@code{#t} if @var{s1} is lexicographically greater than\n"
 267             "@var{s2} regardless of case.")
 268 #define FUNC_NAME s_scm_string_ci_gr_p
 269 {
 270   SCM_VALIDATE_STRING (1, s1);
 271   SCM_VALIDATE_STRING (2, s2);
 272
 273   return string_ci_less_p (s2, s1);
 274 }
 275 #undef FUNC_NAME
 276
 277
 278 SCM_DEFINE1 (scm_string_ci_geq_p, "string-ci>=?", scm_tc7_rpsubr,
 279              (SCM s1, SCM s2),
 280             "Case insensitive lexicographic ordering predicate; return\n"
 281             "@code{#t} if @var{s1} is lexicographically greater than or\n"
 282             "equal to @var{s2} regardless of case.")
 283 #define FUNC_NAME s_scm_string_ci_geq_p
 284 {
 285   SCM_VALIDATE_STRING (1, s1);
 286   SCM_VALIDATE_STRING (2, s2);
 287
 288   return SCM_BOOL_NOT (string_ci_less_p (s1, s2));
 289 }
 290 #undef FUNC_NAME
 291
 292 \f
 293
 294 void
 295 scm_init_strorder ()
 296 {
 297 #ifndef SCM_MAGIC_SNARFER
 298 #include "libguile/strorder.x"
 299 #endif
 300 }
 301
 302
 303 /*
 304   Local Variables:
 305   c-file-style: "gnu"
 306   End:
 307 */