gnulib/lib/unistr/u16-strchr.c

/* Search character in UTF-16 string.
   Copyright (C) 1999, 2002, 2006-2007, 2009-2020 Free Software Foundation,
   Inc.
   Written by Bruno Haible <bruno@clisp.org>, 2002.

   This program is free software: you can redistribute it and/or modify it
   under the terms of the GNU Lesser General Public License as published
   by the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

#include <config.h>

/* Specification.  */
#include "unistr.h"

uint16_t *
u16_strchr (const uint16_t *s, ucs4_t uc)
{
  uint16_t c[2];

  if (uc < 0x10000)
    {
      uint16_t c0 = uc;

      for (;; s++)
        {
          if (*s == c0)
            break;
          if (*s == 0)
            goto notfound;
        }
      return (uint16_t *) s;
    }
  else
    switch (u16_uctomb_aux (c, uc, 2))
      {
      case 2:
        if (*s == 0)
          goto notfound;
        {
          uint16_t c0 = c[0];
          uint16_t c1 = c[1];

          for (;; s++)
            {
              if (s[1] == 0)
                goto notfound;
              if (*s == c0 && s[1] == c1)
                break;
            }
          return (uint16_t *) s;
        }
      }
notfound:
  return NULL;
}