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 
14 static struct nls_table *p_nls;
15 
uni2char(const wchar_t uni,unsigned char * out,int boundlen)16 static 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 
char2uni(const unsigned char * rawstring,int boundlen,wchar_t * uni)39 static 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 
54 static struct nls_table table = {
55 	.charset	= "koi8-ru",
56 	.uni2char	= uni2char,
57 	.char2uni	= char2uni,
58 };
59 
init_nls_koi8_ru(void)60 static 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 
exit_nls_koi8_ru(void)73 static void __exit exit_nls_koi8_ru(void)
74 {
75 	unregister_nls(&table);
76 	unload_nls(p_nls);
77 }
78 
79 module_init(init_nls_koi8_ru)
80 module_exit(exit_nls_koi8_ru)
81 
82 MODULE_LICENSE("Dual BSD/GPL");
83