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., 51 Franklin Street,
18 * Fifth Floor, Boston, MA 02110-1301, USA.
19 */
20
21/*
22 * UCS-2
23 */
24
25/* Here we accept FFFE/FEFF marks as endianness indicators everywhere
26   in the stream, not just at the beginning. The default is big-endian. */
27/* The state is 0 if big-endian, 1 if little-endian. */
28static int
29ucs2_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, int n)
30{
31  state_t state = conv->istate;
32  int count = 0;
33  for (; n >= 2;) {
34    ucs4_t wc = (state ? s[0] + (s[1] << 8) : (s[0] << 8) + s[1]);
35    s += 2; n -= 2; count += 2;
36    if (wc == 0xfeff) {
37    } else if (wc == 0xfffe) {
38      state ^= 1;
39    } else if (wc >= 0xd800 && wc < 0xe000) {
40      return RET_ILSEQ;
41    } else {
42      *pwc = wc;
43      conv->istate = state;
44      return count;
45    }
46  }
47  conv->istate = state;
48  return RET_TOOFEW(count);
49}
50
51/* But we output UCS-2 in big-endian order, without byte-order mark. */
52/* RFC 2152 says:
53   "ISO/IEC 10646-1:1993(E) specifies that when characters the UCS-2 form are
54    serialized as octets, that the most significant octet appear first." */
55static int
56ucs2_wctomb (conv_t conv, unsigned char *r, ucs4_t wc, int n)
57{
58  if (wc < 0x10000 && wc != 0xfffe && !(wc >= 0xd800 && wc < 0xe000)) {
59    if (n >= 2) {
60      r[0] = (unsigned char) (wc >> 8);
61      r[1] = (unsigned char) wc;
62      return 2;
63    } else
64      return RET_TOOSMALL;
65  } else
66    return RET_ILUNI;
67}
68