1/* toutf8.c --- Convert strings from system locale into UTF-8.
2 * Copyright (C) 2002, 2003, 2004, 2005 Simon Josefsson
3 *
4 * This file is part of GNU Libidn.
5 *
6 * GNU Libidn is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * GNU Libidn is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with GNU Libidn; if not, see <http://www.gnu.org/licenses/>.
18 */
19
20#if HAVE_CONFIG_H
21# include "config.h"
22#endif
23
24/* Get prototypes. */
25#include "stringprep.h"
26
27/* Get fprintf. */
28#include <stdio.h>
29
30/* Get getenv. */
31#include <stdlib.h>
32
33/* Get strlen. */
34#include <string.h>
35
36/* Get iconv_string. */
37#include "iconvme.h"
38
39#ifdef _LIBC
40# define HAVE_ICONV 1
41# define LOCALE_WORKS 1
42#endif
43
44#if LOCALE_WORKS
45# include <langinfo.h>
46# include <locale.h>
47#endif
48
49#ifdef _LIBC
50# define stringprep_locale_charset() nl_langinfo (CODESET)
51#else
52/**
53 * stringprep_locale_charset - return charset used in current locale
54 *
55 * Find out current locale charset. The function respect the CHARSET
56 * environment variable, but typically uses nl_langinfo(CODESET) when
57 * it is supported. It fall back on "ASCII" if CHARSET isn't set and
58 * nl_langinfo isn't supported or return anything.
59 *
60 * Note that this function return the application's locale's preferred
61 * charset (or thread's locale's preffered charset, if your system
62 * support thread-specific locales). It does not return what the
63 * system may be using. Thus, if you receive data from external
64 * sources you cannot in general use this function to guess what
65 * charset it is encoded in. Use stringprep_convert from the external
66 * representation into the charset returned by this function, to have
67 * data in the locale encoding.
68 *
69 * Return value: Return the character set used by the current locale.
70 * It will never return NULL, but use "ASCII" as a fallback.
71 **/
72const char *
73stringprep_locale_charset (void)
74{
75 const char *charset = getenv ("CHARSET"); /* flawfinder: ignore */
76
77 if (charset && *charset)
78 return charset;
79
80# ifdef LOCALE_WORKS
81 charset = nl_langinfo (CODESET);
82
83 if (charset && *charset)
84 return charset;
85# endif
86
87 return "ASCII";
88}
89#endif
90
91/**
92 * stringprep_convert - encode string using new character set
93 * @str: input zero-terminated string.
94 * @to_codeset: name of destination character set.
95 * @from_codeset: name of origin character set, as used by @str.
96 *
97 * Convert the string from one character set to another using the
98 * system's iconv() function.
99 *
100 * Return value: Returns newly allocated zero-terminated string which
101 * is @str transcoded into to_codeset.
102 **/
103char *
104stringprep_convert (const char *str,
105 const char *to_codeset, const char *from_codeset)
106{
107#if HAVE_ICONV
108 return iconv_string (str, from_codeset, to_codeset);
109#else
110 char *p;
111 fprintf (stderr, "libidn: warning: libiconv not installed, cannot "
112 "convert data to UTF-8\n");
113 p = malloc (strlen (str) + 1);
114 if (!p)
115 return NULL;
116 return strcpy (p, str);
117#endif
118}
119
120/**
121 * stringprep_locale_to_utf8 - convert locale encoded string to UTF-8
122 * @str: input zero terminated string.
123 *
124 * Convert string encoded in the locale's character set into UTF-8 by
125 * using stringprep_convert().
126 *
127 * Return value: Returns newly allocated zero-terminated string which
128 * is @str transcoded into UTF-8.
129 **/
130char *
131stringprep_locale_to_utf8 (const char *str)
132{
133 return stringprep_convert (str, "UTF-8", stringprep_locale_charset ());
134}
135
136/**
137 * stringprep_utf8_to_locale - encode UTF-8 string to locale encoding
138 * @str: input zero terminated string.
139 *
140 * Convert string encoded in UTF-8 into the locale's character set by
141 * using stringprep_convert().
142 *
143 * Return value: Returns newly allocated zero-terminated string which
144 * is @str transcoded into the locale's character set.
145 **/
146char *
147stringprep_utf8_to_locale (const char *str)
148{
149 return stringprep_convert (str, stringprep_locale_charset (), "UTF-8");
150}
151