1/*
2 * Module for handling utf8 just like any other charset.
3 * By Urban Widmark 2000
4 */
5
6#include <linux/module.h>
7#include <linux/kernel.h>
8#include <linux/string.h>
9#include <linux/nls.h>
10#include <linux/errno.h>
11
12static unsigned char identity[256];
13
14static int uni2char(wchar_t uni, unsigned char *out, int boundlen)
15{
16 int n;
17
18 if (boundlen <= 0)
19 return -ENAMETOOLONG;
20
21 n = utf32_to_utf8(u: uni, s: out, maxlen: boundlen);
22 if (n < 0) {
23 *out = '?';
24 return -EINVAL;
25 }
26 return n;
27}
28
29static int char2uni(const unsigned char *rawstring, int boundlen, wchar_t *uni)
30{
31 int n;
32 unicode_t u;
33
34 n = utf8_to_utf32(s: rawstring, len: boundlen, pu: &u);
35 if (n < 0 || u > MAX_WCHAR_T) {
36 *uni = 0x003f; /* ? */
37 return -EINVAL;
38 }
39 *uni = (wchar_t) u;
40 return n;
41}
42
43static struct nls_table table = {
44 .charset = "utf8",
45 .uni2char = uni2char,
46 .char2uni = char2uni,
47 .charset2lower = identity, /* no conversion */
48 .charset2upper = identity,
49};
50
51static int __init init_nls_utf8(void)
52{
53 int i;
54 for (i=0; i<256; i++)
55 identity[i] = i;
56
57 return register_nls(&table);
58}
59
60static void __exit exit_nls_utf8(void)
61{
62 unregister_nls(&table);
63}
64
65module_init(init_nls_utf8)
66module_exit(exit_nls_utf8)
67MODULE_LICENSE("Dual BSD/GPL");
68

source code of linux/fs/nls/nls_utf8.c