lib/unistr/u16-chr.c

   1 /* Search character in piece of UTF-16 string.
   2    Copyright (C) 1999, 2002, 2006-2007, 2009-2021 Free Software Foundation,
   3    Inc.
   4    Written by Bruno Haible <bruno@clisp.org>, 2002.
   5
   6    This program is free software: you can redistribute it and/or modify it
   7    under the terms of the GNU Lesser General Public License as published
   8    by the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public License
  17    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  18
  19 #include <config.h>
  20
  21 /* Specification.  */
  22 #include "unistr.h"
  23
  24 uint16_t *
  25 u16_chr (const uint16_t *s, size_t n, ucs4_t uc)
  26 {
  27   uint16_t c[2];
  28
  29   if (uc < 0x10000)
  30     {
  31       uint16_t c0 = uc;
  32
  33       for (; n > 0; s++, n--)
  34         {
  35           if (*s == c0)
  36             return (uint16_t *) s;
  37         }
  38     }
  39   else
  40     switch (u16_uctomb_aux (c, uc, 2))
  41       {
  42       case 2:
  43         if (n > 1)
  44           {
  45             uint16_t c0 = c[0];
  46             uint16_t c1 = c[1];
  47
  48             for (n--; n > 0; s++, n--)
  49               {
  50                 if (*s == c0 && s[1] == c1)
  51                   return (uint16_t *) s;
  52               }
  53           }
  54         break;
  55       }
  56   return NULL;
  57 }