string/strcoll.c

   1 /* Copyright (C) 1995, 1996, 1997 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 <stddef.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23
  24 #ifndef STRING_TYPE
  25 # define STRING_TYPE char
  26 # define USTRING_TYPE unsigned char
  27 # define STRCOLL strcoll
  28 # define STRCMP strcmp
  29 #endif
  30
  31 /* Include the shared helper functions.  `strxfrm'/`wcsxfrm' also use
  32    these functions.  */
  33 #include "../locale/weight.h"
  34
  35
  36 /* Compare S1 and S2, returning less than, equal to or
  37    greater than zero if the collated form of S1 is lexicographically
  38    less than, equal to or greater than the collated form of S2.  */
  39 int
  40 STRCOLL (s1, s2)
  41      const STRING_TYPE *s1;
  42      const STRING_TYPE *s2;
  43 {
  44   weight_t *s1forw = NULL;
  45   weight_t *s1backw = NULL;
  46   weight_t *s2forw = NULL;
  47   weight_t *s2backw = NULL;
  48   size_t pass;
  49
  50   /* If the current locale does not specify locale data we use normal
  51      8-bit string comparison.  */
  52   if (collate_nrules == 0)
  53     return STRCMP (s1, s2);
  54
  55   /* Get full information about the strings.  This means we get
  56      information for all passes in a special data structure.  */
  57   get_string (s1, s1forw, s1backw);
  58   get_string (s2, s2forw, s2backw);
  59
  60   /* Now we have all the information.  In at most the given number of
  61      passes we can finally decide about the order.  */
  62   for (pass = 0; pass < collate_nrules; ++pass)
  63     {
  64       int forward = (collate_rules[pass] & sort_forward) != 0;
  65       const weight_t *s1run = forward ? s1forw : s1backw;
  66       const weight_t *s2run = forward ? s2forw : s2backw;
  67       int s1idx = forward ? 0 : s1run->data[pass].number - 1;
  68       int s2idx = forward ? 0 : s2run->data[pass].number - 1;
  69
  70       while (1)
  71         {
  72           int s1ignore = 0;
  73           int s2ignore = 0;
  74           u_int32_t w1 = 0;
  75           u_int32_t w2 = 0;
  76
  77           /* Here we have to check for IGNORE entries.  If these are
  78              found we count them and go on with the next value.  */
  79           while (s1run != NULL
  80                  && ((w1 = s1run->data[pass].value[s1idx])
  81                      == (u_int32_t) IGNORE_CHAR))
  82             {
  83               ++s1ignore;
  84               if ((forward && ++s1idx >= s1run->data[pass].number)
  85                   || (!forward && --s1idx < 0))
  86                 {
  87                   weight_t *nextp = forward ? s1run->next : s1run->prev;
  88                   if (nextp == NULL)
  89                     {
  90                       w1 = 0;
  91                       /* No more non-INGOREd elements means lowest
  92                          possible value.  */
  93                       s1ignore = -1;
  94                     }
  95                   else
  96                     s1idx = forward ? 0 : nextp->data[pass].number - 1;
  97                   s1run = nextp;
  98                 }
  99             }
 100
 101           while (s2run != NULL
 102                  && ((w2 = s2run->data[pass].value[s2idx])
 103                      == (u_int32_t) IGNORE_CHAR))
 104             {
 105               ++s2ignore;
 106               if ((forward && ++s2idx >= s2run->data[pass].number)
 107                   || (!forward && --s2idx < 0))
 108                 {
 109                   weight_t *nextp = forward ? s2run->next : s2run->prev;
 110                   if (nextp == NULL)
 111                     {
 112                       w2 = 0;
 113                       /* No more non-INGOREd elements means lowest
 114                          possible value.  */
 115                       s2ignore = -1;
 116                     }
 117                   else
 118                     s2idx = forward ? 0 : nextp->data[pass].number - 1;
 119                   s2run = nextp;
 120                 }
 121             }
 122
 123           /* If one string is completely processed stop.  */
 124           if (s1run == NULL || s2run == NULL)
 125             break;
 126
 127           /* Now we have information of the number of ignored
 128              weights and the value of the next weight.  */
 129           if ((collate_rules[pass] & sort_position) != 0
 130               && s1ignore != s2ignore && (w1 != 0 || w2 != 0))
 131             return s1ignore < s2ignore ? -1 : 1;
 132
 133           if (w1 != w2)
 134             return w1 < w2 ? -1 : 1;
 135
 136           /* We have to increment the index counters.  */
 137           if ((forward && ++s1idx >= s1run->data[pass].number)
 138               || (!forward && --s1idx < 0))
 139             if (forward)
 140               {
 141                 s1run = s1run->next;
 142                 s1idx = 0;
 143               }
 144             else
 145               {
 146                 s1run = s1run->prev;
 147                 if (s1run != NULL)
 148                   s1idx = s1run->data[pass].number - 1;
 149               }
 150
 151           if ((forward && ++s2idx >= s2run->data[pass].number)
 152               || (!forward && --s2idx < 0))
 153             if (forward)
 154               {
 155                 s2run = s2run->next;
 156                 s2idx = 0;
 157               }
 158             else
 159               {
 160                 s2run = s2run->prev;
 161                 if (s2run != NULL)
 162                   s2idx = s2run->data[pass].number - 1;
 163               }
 164
 165         }
 166
 167       if (s1run != s2run)
 168         return s1run != NULL ? 1 : -1;
 169     }
 170
 171   return 0;
 172 }