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   /* Get full information about the strings.  This means we get
  86      information for all passes in a special data structure.  */
  87   get_string (s1, s1forw, s1backw);
  88   get_string (s2, s2forw, s2backw);
  89
  90   /* Now we have all the information.  In at most the given number of
  91      passes we can finally decide about the order.  */
  92   for (pass = 0; pass < collate_nrules; ++pass)
  93     {
  94       int forward = (collate_rules[pass] & sort_forward) != 0;
  95       const weight_t *s1run = forward ? s1forw : s1backw;
  96       const weight_t *s2run = forward ? s2forw : s2backw;
  97       int s1idx = forward ? 0 : s1run->data[pass].number - 1;
  98       int s2idx = forward ? 0 : s2run->data[pass].number - 1;
  99
 100       while (1)
 101         {
 102           int s1ignore = 0;
 103           int s2ignore = 0;
 104           uint32_t w1 = 0;
 105           uint32_t w2 = 0;
 106
 107           /* Here we have to check for IGNORE entries.  If these are
 108              found we count them and go on with the next value.  */
 109           while (s1run != NULL
 110                  && ((w1 = s1run->data[pass].value[s1idx])
 111                      == (uint32_t) IGNORE_CHAR))
 112             {
 113               ++s1ignore;
 114               if ((forward && ++s1idx >= s1run->data[pass].number)
 115                   || (!forward && --s1idx < 0))
 116                 {
 117                   weight_t *nextp = forward ? s1run->next : s1run->prev;
 118                   if (nextp == NULL)
 119                     {
 120                       w1 = 0;
 121                       /* No more non-INGOREd elements means lowest
 122                          possible value.  */
 123                       s1ignore = -1;
 124                     }
 125                   else
 126                     s1idx = forward ? 0 : nextp->data[pass].number - 1;
 127                   s1run = nextp;
 128                 }
 129             }
 130
 131           while (s2run != NULL
 132                  && ((w2 = s2run->data[pass].value[s2idx])
 133                      == (uint32_t) IGNORE_CHAR))
 134             {
 135               ++s2ignore;
 136               if ((forward && ++s2idx >= s2run->data[pass].number)
 137                   || (!forward && --s2idx < 0))
 138                 {
 139                   weight_t *nextp = forward ? s2run->next : s2run->prev;
 140                   if (nextp == NULL)
 141                     {
 142                       w2 = 0;
 143                       /* No more non-INGOREd elements means lowest
 144                          possible value.  */
 145                       s2ignore = -1;
 146                     }
 147                   else
 148                     s2idx = forward ? 0 : nextp->data[pass].number - 1;
 149                   s2run = nextp;
 150                 }
 151             }
 152
 153           /* If one string is completely processed stop.  */
 154           if (s1run == NULL || s2run == NULL)
 155             break;
 156
 157           /* Now we have information of the number of ignored
 158              weights and the value of the next weight.  */
 159           if ((collate_rules[pass] & sort_position) != 0
 160               && s1ignore != s2ignore && (w1 != 0 || w2 != 0))
 161             return s1ignore < s2ignore ? -1 : 1;
 162
 163           if (w1 != w2)
 164             return w1 < w2 ? -1 : 1;
 165
 166           /* We have to increment the index counters.  */
 167           if ((forward && ++s1idx >= s1run->data[pass].number)
 168               || (!forward && --s1idx < 0))
 169             if (forward)
 170               {
 171                 s1run = s1run->next;
 172                 s1idx = 0;
 173               }
 174             else
 175               {
 176                 s1run = s1run->prev;
 177                 if (s1run != NULL)
 178                   s1idx = s1run->data[pass].number - 1;
 179               }
 180
 181           if ((forward && ++s2idx >= s2run->data[pass].number)
 182               || (!forward && --s2idx < 0))
 183             if (forward)
 184               {
 185                 s2run = s2run->next;
 186                 s2idx = 0;
 187               }
 188             else
 189               {
 190                 s2run = s2run->prev;
 191                 if (s2run != NULL)
 192                   s2idx = s2run->data[pass].number - 1;
 193               }
 194
 195         }
 196
 197       if (s1run != s2run)
 198         return s1run != NULL ? 1 : -1;
 199     }
 200
 201   return 0;
 202 }