1/*
2 * Copyright (C) 2001 Edmund Grimley Evans <edmundo@rano.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
17 */
18
19#include <stdlib.h>
20
21/*
22 * These functions are like the C library's mbtowc() and wctomb(),
23 * but instead of depending on the locale they always work in UTF-8,
24 * and they use int instead of wchar_t.
25 */
26
27int utf8_mbtowc(int *pwc, const char *s, size_t n);
28int utf8_wctomb(char *s, int wc);
29
30/*
31 * This is an object-oriented version of mbtowc() and wctomb().
32 * The caller first uses charset_find() to get a pointer to struct
33 * charset, then uses the mbtowc() and wctomb() methods on it.
34 * The function charset_max() gives the maximum length of a
35 * multibyte character in that encoding.
36 * This API is only appropriate for stateless encodings like UTF-8
37 * or ISO-8859-3, but I have no intention of implementing anything
38 * other than UTF-8 and 8-bit encodings.
39 *
40 * MINOR BUG: If there is no memory charset_find() may return 0 and
41 * there is no way to distinguish this case from an unknown encoding.
42 */
43
44struct charset;
45
46struct charset *charset_find(const char *code);
47
48int charset_mbtowc(struct charset *charset, int *pwc, const char *s, size_t n);
49int charset_wctomb(struct charset *charset, char *s, int wc);
50int charset_max(struct charset *charset);
51
52/*
53 * Function to convert a buffer from one encoding to another.
54 * Invalid bytes are replaced by '#', and characters that are
55 * not available in the target encoding are replaced by '?'.
56 * Each of TO and TOLEN may be zero if the result is not wanted.
57 * The input or output may contain null bytes, but the output
58 * buffer is also null-terminated, so it is all right to
59 * use charset_convert(fromcode, tocode, s, strlen(s), &t, 0).
60 *
61 * Return value:
62 *
63 *  -2 : memory allocation failed
64 *  -1 : unknown encoding
65 *   0 : data was converted exactly
66 *   1 : valid data was converted approximately (using '?')
67 *   2 : input was invalid (but still converted, using '#')
68 */
69
70int charset_convert(const char *fromcode, const char *tocode,
71		    const char *from, size_t fromlen,
72		    char **to, size_t *tolen);
73