string/strcoll.c

   1 /* Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <endian.h>
  21 #include <stddef.h>
  22 #include <stdint.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25
  26 #ifndef STRING_TYPE
  27 # define STRING_TYPE char
  28 # define USTRING_TYPE unsigned char
  29 # ifdef USE_IN_EXTENDED_LOCALE_MODEL
  30 #  define STRCOLL __strcoll_l
  31 # else
  32 #  define STRCOLL strcoll
  33 # endif
  34 # define STRCMP strcmp
  35 #endif
  36
  37 /* Include the shared helper functions.  `strxfrm'/`wcsxfrm' also use
  38    these functions.  */
  39 #include "../locale/weight.h"
  40
  41
  42 /* Compare S1 and S2, returning less than, equal to or
  43    greater than zero if the collated form of S1 is lexicographically
  44    less than, equal to or greater than the collated form of S2.  */
  45 #ifndef USE_IN_EXTENDED_LOCALE_MODEL
  46 int
  47 STRCOLL (s1, s2)
  48      const STRING_TYPE *s1;
  49      const STRING_TYPE *s2;
  50 #else
  51 int
  52 STRCOLL (s1, s2, l)
  53      const STRING_TYPE *s1;
  54      const STRING_TYPE *s2;
  55      __locale_t l;
  56 #endif
  57 {
  58 #ifdef USE_IN_EXTENDED_LOCALE_MODEL
  59   struct locale_data *current = l->__locales[LC_COLLATE];
  60 # if BYTE_ORDER == BIG_ENDIAN
  61   const uint32_t *collate_table = (const uint32_t *)
  62     current->values[_NL_ITEM_INDEX (_NL_COLLATE_TABLE_EB)].string;
  63   const uint32_t *collate_extra = (const uint32_t *)
  64     current->values[_NL_ITEM_INDEX (_NL_COLLATE_EXTRA_EB)].string;
  65 # elif BYTE_ORDER == LITTLE_ENDIAN
  66   const uint32_t *collate_table = (const uint32_t *)
  67     current->values[_NL_ITEM_INDEX (_NL_COLLATE_TABLE_EL)].string;
  68   const uint32_t *collate_extra = (const uint32_t *)
  69     current->values[_NL_ITEM_INDEX (_NL_COLLATE_EXTRA_EL)].string;
  70 # else
  71 #  error bizarre byte order
  72 # endif
  73 #endif
  74   weight_t *s1forw = NULL;
  75   weight_t *s1backw = NULL;
  76   weight_t *s2forw = NULL;
  77   weight_t *s2backw = NULL;
  78   size_t pass;
  79
  80   /* If the current locale does not specify locale data we use normal
  81      8-bit string comparison.  */
  82   if (collate_nrules == 0)
  83     return STRCMP (s1, s2);
  84
  85   /* Handle empty strings as a special case.  */
  86   if (*s1 == '\0')
  87     return *s2 == '\0' ? 0 : -1;
  88   else if (*s2 == '\0')
  89     return 1;
  90
  91   /* Get full information about the strings.  This means we get
  92      information for all passes in a special data structure.  */
  93   get_string (s1, s1forw, s1backw);
  94   get_string (s2, s2forw, s2backw);
  95
  96   /* Now we have all the information.  In at most the given number of
  97      passes we can finally decide about the order.  */
  98   for (pass = 0; pass < collate_nrules; ++pass)
  99     {
 100       int forward = (collate_rules[pass] & sort_forward) != 0;
 101       const weight_t *s1run = forward ? s1forw : s1backw;
 102       const weight_t *s2run = forward ? s2forw : s2backw;
 103       int s1idx = forward ? 0 : s1run->data[pass].number - 1;
 104       int s2idx = forward ? 0 : s2run->data[pass].number - 1;
 105
 106       while (1)
 107         {
 108           int s1ignore = 0;
 109           int s2ignore = 0;
 110           uint32_t w1 = 0;
 111           uint32_t w2 = 0;
 112
 113           /* Here we have to check for IGNORE entries.  If these are
 114              found we count them and go on with the next value.  */
 115           while (s1run != NULL
 116                  && ((w1 = s1run->data[pass].value[s1idx])
 117                      == (uint32_t) IGNORE_CHAR))
 118             {
 119               ++s1ignore;
 120               if ((forward && ++s1idx >= s1run->data[pass].number)
 121                   || (!forward && --s1idx < 0))
 122                 {
 123                   weight_t *nextp = forward ? s1run->next : s1run->prev;
 124                   if (nextp == NULL)
 125                     {
 126                       w1 = 0;
 127                       /* No more non-INGOREd elements means lowest
 128                          possible value.  */
 129                       s1ignore = -1;
 130                     }
 131                   else
 132                     s1idx = forward ? 0 : nextp->data[pass].number - 1;
 133                   s1run = nextp;
 134                 }
 135             }
 136
 137           while (s2run != NULL
 138                  && ((w2 = s2run->data[pass].value[s2idx])
 139                      == (uint32_t) IGNORE_CHAR))
 140             {
 141               ++s2ignore;
 142               if ((forward && ++s2idx >= s2run->data[pass].number)
 143                   || (!forward && --s2idx < 0))
 144                 {
 145                   weight_t *nextp = forward ? s2run->next : s2run->prev;
 146                   if (nextp == NULL)
 147                     {
 148                       w2 = 0;
 149                       /* No more non-INGOREd elements means lowest
 150                          possible value.  */
 151                       s2ignore = -1;
 152                     }
 153                   else
 154                     s2idx = forward ? 0 : nextp->data[pass].number - 1;
 155                   s2run = nextp;
 156                 }
 157             }
 158
 159           /* If one string is completely processed stop.  */
 160           if (s1run == NULL || s2run == NULL)
 161             break;
 162
 163           /* Now we have information of the number of ignored
 164              weights and the value of the next weight.  */
 165           if ((collate_rules[pass] & sort_position) != 0
 166               && s1ignore != s2ignore && (w1 != 0 || w2 != 0))
 167             return s1ignore < s2ignore ? -1 : 1;
 168
 169           if (w1 != w2)
 170             return w1 < w2 ? -1 : 1;
 171
 172           /* We have to increment the index counters.  */
 173           if ((forward && ++s1idx >= s1run->data[pass].number)
 174               || (!forward && --s1idx < 0))
 175             if (forward)
 176               {
 177                 s1run = s1run->next;
 178                 s1idx = 0;
 179               }
 180             else
 181               {
 182                 s1run = s1run->prev;
 183                 if (s1run != NULL)
 184                   s1idx = s1run->data[pass].number - 1;
 185               }
 186
 187           if ((forward && ++s2idx >= s2run->data[pass].number)
 188               || (!forward && --s2idx < 0))
 189             if (forward)
 190               {
 191                 s2run = s2run->next;
 192                 s2idx = 0;
 193               }
 194             else
 195               {
 196                 s2run = s2run->prev;
 197                 if (s2run != NULL)
 198                   s2idx = s2run->data[pass].number - 1;
 199               }
 200
 201         }
 202
 203       if (s1run != s2run)
 204         return s1run != NULL ? 1 : -1;
 205     }
 206
 207   return 0;
 208 }