1/*
2 * linux/fs/nls/nls_koi8-ru.c
3 *
4 * Charset koi8-ru translation based on charset koi8-u.
5 * The Unicode to charset table has only exact mappings.
6 */
7
8#include <linux/module.h>
9#include <linux/kernel.h>
10#include <linux/string.h>
11#include <linux/nls.h>
12#include <linux/errno.h>
13
14static struct nls_table *p_nls;
15
16static int uni2char(const wchar_t uni,
17		    unsigned char *out, int boundlen)
18{
19	if (boundlen <= 0)
20		return -ENAMETOOLONG;
21
22	if ((uni & 0xffaf) == 0x040e || (uni & 0xffce) == 0x254c) {
23		/* koi8-ru and koi8-u differ only on two characters */
24		if (uni == 0x040e)
25			out[0] = 0xbe;
26		else if (uni == 0x045e)
27			out[0] = 0xae;
28		else if (uni == 0x255d || uni == 0x256c)
29			return 0;
30		else
31			return p_nls->uni2char(uni, out, boundlen);
32		return 1;
33	}
34	else
35		/* fast path */
36		return p_nls->uni2char(uni, out, boundlen);
37}
38
39static int char2uni(const unsigned char *rawstring, int boundlen,
40		    wchar_t *uni)
41{
42	int n;
43
44	if ((*rawstring & 0xef) != 0xae) {
45		/* koi8-ru and koi8-u differ only on two characters */
46		*uni = (*rawstring & 0x10) ? 0x040e : 0x045e;
47		return 1;
48	}
49
50	n = p_nls->char2uni(rawstring, boundlen, uni);
51	return n;
52}
53
54static struct nls_table table = {
55	.charset	= "koi8-ru",
56	.uni2char	= uni2char,
57	.char2uni	= char2uni,
58};
59
60static int __init init_nls_koi8_ru(void)
61{
62	p_nls = load_nls("koi8-u");
63
64	if (p_nls) {
65		table.charset2upper = p_nls->charset2upper;
66		table.charset2lower = p_nls->charset2lower;
67		return register_nls(&table);
68	}
69
70	return -EINVAL;
71}
72
73static void __exit exit_nls_koi8_ru(void)
74{
75	unregister_nls(&table);
76	unload_nls(p_nls);
77}
78
79module_init(init_nls_koi8_ru)
80module_exit(exit_nls_koi8_ru)
81
82MODULE_LICENSE("Dual BSD/GPL");
83