root/maint/gnulib/lib/uninorm/composition.c

/* */

DEFINITIONS

1. uc_composition

   1 /* Canonical composition of Unicode characters.
   2    Copyright (C) 2002, 2006, 2009, 2011-2021 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2009.
   4 
   5    This file is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU Lesser General Public License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    License, or (at your option) any later version.
   9 
  10    This file 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
  13    GNU Lesser General Public License for more details.
  14 
  15    You should have received a copy of the GNU Lesser General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17 
  18 #include <config.h>
  19 
  20 /* Specification.  */
  21 #include "uninorm.h"
  22 
  23 #include <string.h>
  24 
  25 struct composition_rule { char codes[6]; unsigned int combined; };
  26 
  27 #include "composition-table.h"
  28 
  29 ucs4_t
  30 uc_composition (ucs4_t uc1, ucs4_t uc2)
     /*  */
  31 {
  32   if (uc1 < 0x12000 && uc2 < 0x12000)
  33     {
  34       if (uc2 >= 0x1161 && uc2 < 0x1161 + 21
  35           && uc1 >= 0x1100 && uc1 < 0x1100 + 19)
  36         {
  37           /* Hangul: Combine single letter L and single letter V to form
  38              two-letter syllable LV.  */
  39           return 0xAC00 + ((uc1 - 0x1100) * 21 + (uc2 - 0x1161)) * 28;
  40         }
  41       else if (uc2 > 0x11A7 && uc2 < 0x11A7 + 28
  42                && uc1 >= 0xAC00 && uc1 < 0xD7A4 && ((uc1 - 0xAC00) % 28) == 0)
  43         {
  44           /* Hangul: Combine two-letter syllable LV with single-letter T
  45              to form three-letter syllable LVT.  */
  46           return uc1 + (uc2 - 0x11A7);
  47         }
  48       else
  49         {
  50 #if 0
  51           unsigned int uc = MUL1 * uc1 * MUL2 * uc2;
  52           unsigned int index1 = uc >> composition_header_0;
  53           if (index1 < composition_header_1)
  54             {
  55               int lookup1 = u_composition.level1[index1];
  56               if (lookup1 >= 0)
  57                 {
  58                   unsigned int index2 = (uc >> composition_header_2) & composition_header_3;
  59                   int lookup2 = u_composition.level2[lookup1 + index2];
  60                   if (lookup2 >= 0)
  61                     {
  62                       unsigned int index3 = (uc & composition_header_4);
  63                       unsigned int lookup3 = u_composition.level3[lookup2 + index3];
  64                       if ((lookup3 >> 16) == uc2)
  65                         return lookup3 & ((1U << 16) - 1);
  66                     }
  67                 }
  68             }
  69 #else
  70           char codes[6];
  71           const struct composition_rule *rule;
  72 
  73           codes[0] = (uc1 >> 16) & 0xff;
  74           codes[1] = (uc1 >> 8) & 0xff;
  75           codes[2] = uc1 & 0xff;
  76           codes[3] = (uc2 >> 16) & 0xff;
  77           codes[4] = (uc2 >> 8) & 0xff;
  78           codes[5] = uc2 & 0xff;
  79 
  80           rule = gl_uninorm_compose_lookup (codes, 6);
  81           if (rule != NULL)
  82             return rule->combined;
  83 #endif
  84         }
  85     }
  86   return 0;
  87 }

/* */