lib/utf16be.h

   1 /*
   2  * Copyright (C) 1999-2001 Free Software Foundation, Inc.
   3  * This file is part of the GNU LIBICONV Library.
   4  *
   5  * The GNU LIBICONV Library is free software; you can redistribute it
   6  * and/or modify it under the terms of the GNU Library General Public
   7  * License as published by the Free Software Foundation; either version 2
   8  * of the License, or (at your option) any later version.
   9  *
  10  * The GNU LIBICONV Library is distributed in the hope that it will be
  11  * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Library General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Library General Public
  16  * License along with the GNU LIBICONV Library; see the file COPYING.LIB.
  17  * If not, write to the Free Software Foundation, Inc., 59 Temple Place -
  18  * Suite 330, Boston, MA 02111-1307, USA.
  19  */
  20
  21 /*
  22  * UTF-16BE
  23  */
  24
  25 /* Specification: RFC 2781 */
  26
  27 static int
  28 utf16be_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, int n)
  29 {
  30   int count = 0;
  31   if (n >= 2) {
  32     ucs4_t wc = (s[0] << 8) + s[1];
  33     if (wc >= 0xd800 && wc < 0xdc00) {
  34       if (n >= 4) {
  35         ucs4_t wc2 = (s[2] << 8) + s[3];
  36         if (!(wc2 >= 0xdc00 && wc2 < 0xe000))
  37           return RET_ILSEQ;
  38         *pwc = 0x10000 + ((wc - 0xd800) << 10) + (wc2 - 0xdc00);
  39         return count+4;
  40       }
  41     } else if (wc >= 0xdc00 && wc < 0xe000) {
  42       return RET_ILSEQ;
  43     } else {
  44       *pwc = wc;
  45       return count+2;
  46     }
  47   }
  48   return RET_TOOFEW(count);
  49 }
  50
  51 static int
  52 utf16be_wctomb (conv_t conv, unsigned char *r, ucs4_t wc, int n)
  53 {
  54   if (!(wc >= 0xd800 && wc < 0xe000)) {
  55     if (wc < 0x10000) {
  56       if (n >= 2) {
  57         r[0] = (unsigned char) (wc >> 8);
  58         r[1] = (unsigned char) wc;
  59         return 2;
  60       } else
  61         return RET_TOOSMALL;
  62     }
  63     else if (wc < 0x110000) {
  64       if (n >= 4) {
  65         ucs4_t wc1 = 0xd800 + ((wc - 0x10000) >> 10);
  66         ucs4_t wc2 = 0xdc00 + ((wc - 0x10000) & 0x3ff);
  67         r[0] = (unsigned char) (wc1 >> 8);
  68         r[1] = (unsigned char) wc1;
  69         r[2] = (unsigned char) (wc2 >> 8);
  70         r[3] = (unsigned char) wc2;
  71         return 4;
  72       } else
  73         return RET_TOOSMALL;
  74     }
  75   }
  76   return RET_ILUNI;
  77 }