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 <stdio.h>
  47 #include "libguile/_scm.h"
  48 #include "libguile/chars.h"
  49 #include "libguile/strings.h"
  50 #include "libguile/symbols.h"
  51
  52 #include "libguile/validate.h"
  53 #include "libguile/strorder.h"
  54 \f
  55
  56 SCM_DEFINE1 (scm_string_equal_p, "string=?", scm_tc7_rpsubr,
  57              (SCM s1, SCM s2),
  58              "Lexicographic equality predicate; \n"
  59              "Returns @code{#t} if the two strings are the same length and\n"
  60              "contain the same characters in the same positions, otherwise\n"
  61              "returns @code{#f}. (r5rs)\n\n"
  62              "The procedure @code{string-ci=?} treats upper and lower case\n"
  63              "letters as though they were the same character, but\n"
  64              "@code{string=?} treats upper and lower case as distinct\n"
  65              "characters.")
  66 #define FUNC_NAME s_scm_string_equal_p
  67 {
  68   scm_sizet length;
  69
  70   SCM_VALIDATE_STRING (1, s1);
  71   SCM_VALIDATE_STRING (2, s2);
  72
  73   length = SCM_STRING_LENGTH (s2);
  74   if (SCM_STRING_LENGTH (s1) == length)
  75     {
  76       unsigned char *c1 = SCM_STRING_UCHARS (s1) + length - 1;
  77       unsigned char *c2 = SCM_STRING_UCHARS (s2) + length - 1;
  78       scm_sizet i;
  79
  80       /* comparing from back to front typically finds mismatches faster */
  81       for (i = 0; i != length; ++i, --c1, --c2)
  82         if (*c1 != *c2)
  83           return SCM_BOOL_F;
  84
  85       return SCM_BOOL_T;
  86     }
  87   else
  88     {
  89       return SCM_BOOL_F;
  90     }
  91 }
  92 #undef FUNC_NAME
  93
  94
  95 SCM_DEFINE1 (scm_string_ci_equal_p, "string-ci=?", scm_tc7_rpsubr,
  96              (SCM s1, SCM s2),
  97              "Case-insensitive string equality predicate; returns @code{#t}\n"
  98              "if the two strings are the same length and their component\n"
  99              "characters match (ignoring case) at each position; otherwise\n"
 100              "returns @code{#f}. (r5rs)")
 101 #define FUNC_NAME s_scm_string_ci_equal_p
 102 {
 103   scm_sizet length;
 104
 105   SCM_VALIDATE_STRING (1, s1);
 106   SCM_VALIDATE_STRING (2, s2);
 107
 108   length = SCM_STRING_LENGTH (s2);
 109   if (SCM_STRING_LENGTH (s1) == length)
 110     {
 111       unsigned char *c1 = SCM_STRING_UCHARS (s1) + length - 1;
 112       unsigned char *c2 = SCM_STRING_UCHARS (s2) + length - 1;
 113       scm_sizet i;
 114
 115       /* comparing from back to front typically finds mismatches faster */
 116       for (i = 0; i != length; ++i, --c1, --c2)
 117         if (scm_upcase (*c1) != scm_upcase (*c2))
 118           return SCM_BOOL_F;
 119
 120       return SCM_BOOL_T;
 121     }
 122   else
 123     {
 124       return SCM_BOOL_F;
 125     }
 126 }
 127 #undef FUNC_NAME
 128
 129
 130 /* Helper function for the lexicographic ordering predicates.
 131  * No argument checking is performed.  */
 132 static SCM
 133 string_less_p (SCM s1, SCM s2)
 134 {
 135   scm_sizet i, length1, length2, lengthm;
 136   unsigned char *c1, *c2;
 137
 138   length1 = SCM_STRING_LENGTH (s1);
 139   length2 = SCM_STRING_LENGTH (s2);
 140   lengthm = min (length1, length2);
 141   c1 = SCM_STRING_UCHARS (s1);
 142   c2 = SCM_STRING_UCHARS (s2);
 143
 144   for (i = 0; i != lengthm; ++i, ++c1, ++c2) {
 145     int c = *c1 - *c2;
 146     if (c < 0) return SCM_BOOL_T;
 147     if (c > 0) return SCM_BOOL_F;
 148   }
 149
 150   return SCM_BOOL (length1 < length2);
 151 }
 152
 153
 154 SCM_DEFINE1 (scm_string_less_p, "string<?", scm_tc7_rpsubr,
 155              (SCM s1, SCM s2),
 156              "Lexicographic ordering predicate; returns @code{#t} if\n"
 157              "@var{s1} is lexicographically less than @var{s2}.  (r5rs)")
 158 #define FUNC_NAME s_scm_string_less_p
 159 {
 160   SCM_VALIDATE_STRING (1, s1);
 161   SCM_VALIDATE_STRING (2, s2);
 162
 163   return string_less_p (s1, s2);
 164 }
 165 #undef FUNC_NAME
 166
 167
 168 SCM_DEFINE1 (scm_string_leq_p, "string<=?", scm_tc7_rpsubr,
 169              (SCM s1, SCM s2),
 170              "Lexicographic ordering predicate; returns @code{#t} if\n"
 171              "@var{s1} is lexicographically less than or equal to @var{s2}.\n"
 172              "(r5rs)")
 173 #define FUNC_NAME s_scm_string_leq_p
 174 {
 175   SCM_VALIDATE_STRING (1, s1);
 176   SCM_VALIDATE_STRING (2, s2);
 177
 178   return SCM_BOOL_NOT (string_less_p (s2, s1));
 179 }
 180 #undef FUNC_NAME
 181
 182
 183 SCM_DEFINE1 (scm_string_gr_p, "string>?", scm_tc7_rpsubr,
 184              (SCM s1, SCM s2),
 185              "Lexicographic ordering predicate; returns @code{#t} if\n"
 186              "@var{s1} is lexicographically greater than @var{s2}.  (r5rs)")
 187 #define FUNC_NAME s_scm_string_gr_p
 188 {
 189   SCM_VALIDATE_STRING (1, s1);
 190   SCM_VALIDATE_STRING (2, s2);
 191
 192   return string_less_p (s2, s1);
 193 }
 194 #undef FUNC_NAME
 195
 196
 197 SCM_DEFINE1 (scm_string_geq_p, "string>=?", scm_tc7_rpsubr,
 198              (SCM s1, SCM s2),
 199              "Lexicographic ordering predicate; returns @code{#t} if\n"
 200              "@var{s1} is lexicographically greater than or equal to\n"
 201              "@var{s2}.  (r5rs)")
 202 #define FUNC_NAME s_scm_string_geq_p
 203 {
 204   SCM_VALIDATE_STRING (1, s1);
 205   SCM_VALIDATE_STRING (2, s2);
 206
 207   return SCM_BOOL_NOT (string_less_p (s1, s2));
 208 }
 209 #undef FUNC_NAME
 210
 211
 212 /* Helper function for the case insensitive lexicographic ordering
 213  * predicates.  No argument checking is performed.  */
 214 static SCM
 215 string_ci_less_p (SCM s1, SCM s2)
 216 {
 217   scm_sizet i, length1, length2, lengthm;
 218   unsigned char *c1, *c2;
 219
 220   length1 = SCM_STRING_LENGTH (s1);
 221   length2 = SCM_STRING_LENGTH (s2);
 222   lengthm = min (length1, length2);
 223   c1 = SCM_STRING_UCHARS (s1);
 224   c2 = SCM_STRING_UCHARS (s2);
 225
 226   for (i = 0; i != lengthm; ++i, ++c1, ++c2) {
 227     int c = scm_upcase (*c1) - scm_upcase (*c2);
 228     if (c < 0) return SCM_BOOL_T;
 229     if (c > 0) return SCM_BOOL_F;
 230   }
 231
 232   return SCM_BOOL (length1 < length2);
 233 }
 234
 235
 236 SCM_DEFINE1 (scm_string_ci_less_p, "string-ci<?", scm_tc7_rpsubr,
 237              (SCM s1, SCM s2),
 238              "Case insensitive lexicographic ordering predicate;\n"
 239              "returns @code{#t} if @var{s1} is lexicographically less than\n"
 240              "@var{s2} regardless of case.  (r5rs)")
 241 #define FUNC_NAME s_scm_string_ci_less_p
 242 {
 243   SCM_VALIDATE_STRING (1, s1);
 244   SCM_VALIDATE_STRING (2, s2);
 245
 246   return string_ci_less_p (s1, s2);
 247 }
 248 #undef FUNC_NAME
 249
 250
 251 SCM_DEFINE1 (scm_string_ci_leq_p, "string-ci<=?", scm_tc7_rpsubr,
 252              (SCM s1, SCM s2),
 253              "Case insensitive lexicographic ordering predicate;\n"
 254              "returns @code{#t} if @var{s1} is lexicographically less than\n"
 255              "or equal to @var{s2} regardless of case.  (r5rs)")
 256 #define FUNC_NAME s_scm_string_ci_leq_p
 257 {
 258   SCM_VALIDATE_STRING (1, s1);
 259   SCM_VALIDATE_STRING (2, s2);
 260
 261   return SCM_BOOL_NOT (string_ci_less_p (s2, s1));
 262 }
 263 #undef FUNC_NAME
 264
 265
 266 SCM_DEFINE1 (scm_string_ci_gr_p, "string-ci>?", scm_tc7_rpsubr,
 267              (SCM s1, SCM s2),
 268              "Case insensitive lexicographic ordering predicate;\n"
 269              "returns @code{#t} if @var{s1} is lexicographically greater\n"
 270              "than @var{s2} regardless of case.  (r5rs)")
 271 #define FUNC_NAME s_scm_string_ci_gr_p
 272 {
 273   SCM_VALIDATE_STRING (1, s1);
 274   SCM_VALIDATE_STRING (2, s2);
 275
 276   return string_ci_less_p (s2, s1);
 277 }
 278 #undef FUNC_NAME
 279
 280
 281 SCM_DEFINE1 (scm_string_ci_geq_p, "string-ci>=?", scm_tc7_rpsubr,
 282              (SCM s1, SCM s2),
 283              "Case insensitive lexicographic ordering predicate;\n"
 284              "returns @code{#t} if @var{s1} is lexicographically greater\n"
 285              "than or equal to @var{s2} regardless of case.  (r5rs)")
 286 #define FUNC_NAME s_scm_string_ci_geq_p
 287 {
 288   SCM_VALIDATE_STRING (1, s1);
 289   SCM_VALIDATE_STRING (2, s2);
 290
 291   return SCM_BOOL_NOT (string_ci_less_p (s1, s2));
 292 }
 293 #undef FUNC_NAME
 294
 295 \f
 296
 297 void
 298 scm_init_strorder ()
 299 {
 300 #ifndef SCM_MAGIC_SNARFER
 301 #include "libguile/strorder.x"
 302 #endif
 303 }
 304
 305
 306 /*
 307   Local Variables:
 308   c-file-style: "gnu"
 309   End:
 310 */