lib/unictype/joininggroup_of.c

   1 /* Arabic joining group of Unicode characters.
   2    Copyright (C) 2011-2021 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2011.
   4
   5    This program is free software: you can redistribute it and/or modify it
   6    under the terms of the GNU Lesser General Public License as published
   7    by the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program 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    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 "unictype.h"
  22
  23 /* Define u_joining_group table.  */
  24 #include "joininggroup_of.h"
  25
  26 int
  27 uc_joining_group (ucs4_t uc)
  28 {
  29   unsigned int index1 = uc >> joining_group_header_0;
  30   if (index1 < joining_group_header_1)
  31     {
  32       int lookup1 = u_joining_group.level1[index1];
  33       if (lookup1 >= 0)
  34         {
  35           unsigned int index2 = (uc >> joining_group_header_2) & joining_group_header_3;
  36           int lookup2 = u_joining_group.level2[lookup1 + index2];
  37           if (lookup2 >= 0)
  38             {
  39               unsigned int index3 = ((uc & joining_group_header_4) + lookup2) * 7;
  40               /* level3 contains 7-bit values, packed into 16-bit words.  */
  41               unsigned int lookup3 =
  42                 (((unsigned int) u_joining_group.level3[index3>>4]
  43                   | ((unsigned int) u_joining_group.level3[(index3>>4)+1] << 16))
  44                  >> (index3 % 16))
  45                 & 0x7f;
  46
  47               return lookup3;
  48             }
  49         }
  50     }
  51   return UC_JOINING_GROUP_NONE;
  52 }