lib/unicase/simple-mapping.h

   1 /* Simple case mapping for Unicode characters.
   2    Copyright (C) 2002, 2006, 2009-2020 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2009.
   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 ucs4_t
  19 FUNC (ucs4_t uc)
  20 {
  21   unsigned int index1 = uc >> mapping_header_0;
  22   if (index1 < mapping_header_1)
  23     {
  24       int lookup1 = u_mapping.level1[index1];
  25       if (lookup1 >= 0)
  26         {
  27           unsigned int index2 = (uc >> mapping_header_2) & mapping_header_3;
  28           int lookup2 = u_mapping.level2[lookup1 + index2];
  29           if (lookup2 >= 0)
  30             {
  31               unsigned int index3 = (uc & mapping_header_4);
  32               int lookup3 = u_mapping.level3[lookup2 + index3];
  33
  34               return uc + lookup3;
  35             }
  36         }
  37     }
  38   return uc;
  39 }