string/strcoll.c

   1 /* Copyright (C) 1995, 1996 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
  17 not, 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       do
  71         {
  72           int s1ignore = 0;
  73           int s2ignore = 0;
  74           u_int32_t w1, w2;
  75
  76           /* Here we have to check for IGNORE entries.  If these are
  77              found we count them and go on witht he next value.  */
  78           while ((w1 = s1run->data[pass].value[s1idx]) == IGNORE_CHAR)
  79             {
  80               ++s1ignore;
  81               if ((forward && ++s1idx >= s1run->data[pass].number)
  82                   || (!forward && --s1idx < 0))
  83                 {
  84                   weight_t *nextp = forward ? s1run->next : s1run->prev;
  85                   if (nextp == NULL)
  86                     {
  87                       w1 = 0;
  88                       break;
  89                     }
  90                   s1run = nextp;
  91                   s1idx = forward ? 0 : s1run->data[pass].number - 1;
  92                 }
  93             }
  94
  95           while ((w2 = s2run->data[pass].value[s2idx]) == IGNORE_CHAR)
  96             {
  97               ++s2ignore;
  98               if ((forward && ++s2idx >= s2run->data[pass].number)
  99                   || (!forward && --s2idx < 0))
 100                 {
 101                   weight_t *nextp = forward ? s2run->next : s2run->prev;
 102                   if (nextp == NULL)
 103                     {
 104                       w2 = 0;
 105                       break;
 106                     }
 107                   s2run = nextp;
 108                   s2idx = forward ? 0 : s2run->data[pass].number - 1;
 109                 }
 110             }
 111
 112           /* Now we have information of the number of ignored
 113              weights and the value of the next weight.  */
 114           if ((collate_rules[pass] & sort_position) != 0
 115               && s1ignore != s2ignore && (w1 != 0 || w2 != 0))
 116             return s1ignore < s2ignore ? -1 : 1;
 117
 118           if (w1 != w2)
 119             return w1 < w2 ? -1 : 1;
 120
 121           /* We have to increment the index counters.  */
 122           if ((forward && ++s1idx >= s1run->data[pass].number)
 123               || (!forward && --s1idx < 0))
 124             if (forward)
 125               {
 126                 s1run = s1run->next;
 127                 s1idx = 0;
 128               }
 129             else
 130               {
 131                 s1run = s1run->prev;
 132                 if (s1run != NULL)
 133                   s1idx = s1run->data[pass].number - 1;
 134               }
 135
 136           if ((forward && ++s2idx >= s2run->data[pass].number)
 137               || (!forward && --s2idx < 0))
 138             if (forward)
 139               {
 140                 s2run = s2run->next;
 141                 s2idx = 0;
 142               }
 143             else
 144               {
 145                 s2run = s2run->prev;
 146                 if (s2run != NULL)
 147                   s2idx = s2run->data[pass].number - 1;
 148               }
 149
 150         }
 151       while (s1run != NULL && s2run != NULL);
 152
 153       if (s1run != s2run)
 154         return s1run != NULL ? 1 : -1;
 155     }
 156
 157   return 0;
 158 }