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 * UTF-32
23 */
24
25/* Specification: Unicode 3.1 Standard Annex #19 */
26
27/* Here we accept FFFE0000/0000FEFF marks as endianness indicators
28   everywhere in the stream, not just at the beginning. (This is contrary
29   to what #19 D36c specifies, but it allows concatenation of byte
30   sequences to work flawlessly, while disagreeing with #19 behaviour
31   only for strings containing U+FEFF characters, which is quite rare.)
32   The default is big-endian. */
33/* The state is 0 if big-endian, 1 if little-endian. */
34static int
35utf32_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, int n)
36{
37  state_t state = conv->istate;
38  int count = 0;
39  for (; n >= 4;) {
40    ucs4_t wc = (state
41                  ? s[0] + (s[1] << 8) + (s[2] << 16) + (s[3] << 24)
42                  : (s[0] << 24) + (s[1] << 16) + (s[2] << 8) + s[3]);
43    count += 4;
44    if (wc == 0x0000feff) {
45    } else if (wc == 0xfffe0000u) {
46      state ^= 1;
47    } else {
48      if (wc < 0x110000 && !(wc >= 0xd800 && wc < 0xe000)) {
49        *pwc = wc;
50        conv->istate = state;
51        return count;
52      } else
53        return RET_ILSEQ;
54    }
55    s += 4; n -= 4;
56  }
57  conv->istate = state;
58  return RET_TOOFEW(count);
59}
60
61/* We output UTF-32 in big-endian order, with byte-order mark. */
62/* The state is 0 at the beginning, 1 after the BOM has been written. */
63static int
64utf32_wctomb (conv_t conv, unsigned char *r, ucs4_t wc, int n)
65{
66  if (wc < 0x110000 && !(wc >= 0xd800 && wc < 0xe000)) {
67    int count = 0;
68    if (!conv->ostate) {
69      if (n >= 4) {
70        r[0] = 0x00;
71        r[1] = 0x00;
72        r[2] = 0xFE;
73        r[3] = 0xFF;
74        r += 4; n -= 4; count += 4;
75      } else
76        return RET_TOOSMALL;
77    }
78    if (wc < 0x110000) {
79      if (n >= 4) {
80        r[0] = 0;
81        r[1] = (unsigned char) (wc >> 16);
82        r[2] = (unsigned char) (wc >> 8);
83        r[3] = (unsigned char) wc;
84        conv->ostate = 1;
85        return count+4;
86      } else
87        return RET_TOOSMALL;
88    }
89  }
90  return RET_ILUNI;
91}
92