projects/linux·blob v4.8 · refs

108 lines · 3.0 KiB

1#ifndef _LINUX_NLS_H
2#define _LINUX_NLS_H
3
4#include <linux/init.h>
5
6/* Unicode has changed over the years. Unicode code points no longer
7 * fit into 16 bits; as of Unicode 5 valid code points range from 0
8 * to 0x10ffff (17 planes, where each plane holds 65536 code points).
9 *
10 * The original decision to represent Unicode characters as 16-bit
11 * wchar_t values is now outdated. But plane 0 still includes the
12 * most commonly used characters, so we will retain it. The newer
13 * 32-bit unicode_t type can be used when it is necessary to
14 * represent the full Unicode character set.
15 */
16
17/* Plane-0 Unicode character */
18typedef u16 wchar_t;
19#define MAX_WCHAR_T 0xffff
20
21/* Arbitrary Unicode character */
22typedef u32 unicode_t;
23
24struct nls_table {
25 const char *charset;
26 const char *alias;
27 int (*uni2char) (wchar_t uni, unsigned char *out, int boundlen);
28 int (*char2uni) (const unsigned char *rawstring, int boundlen,
29 wchar_t *uni);
30 const unsigned char *charset2lower;
31 const unsigned char *charset2upper;
32 struct module *owner;
33 struct nls_table *next;
34};
35
36/* this value hold the maximum octet of charset */
37#define NLS_MAX_CHARSET_SIZE 6 /* for UTF-8 */
38
39/* Byte order for UTF-16 strings */
40enum utf16_endian {
41 UTF16_HOST_ENDIAN,
42 UTF16_LITTLE_ENDIAN,
43 UTF16_BIG_ENDIAN
44};
45
46/* nls_base.c */
47extern int __register_nls(struct nls_table *, struct module *);
48extern int unregister_nls(struct nls_table *);
49extern struct nls_table *load_nls(char *);
50extern void unload_nls(struct nls_table *);
51extern struct nls_table *load_nls_default(void);
52#define register_nls(nls) __register_nls((nls), THIS_MODULE)
53
54extern int utf8_to_utf32(const u8 *s, int len, unicode_t *pu);
55extern int utf32_to_utf8(unicode_t u, u8 *s, int maxlen);
56extern int utf8s_to_utf16s(const u8 *s, int len,
57 enum utf16_endian endian, wchar_t *pwcs, int maxlen);
58extern int utf16s_to_utf8s(const wchar_t *pwcs, int len,
59 enum utf16_endian endian, u8 *s, int maxlen);
60
61static inline unsigned char nls_tolower(struct nls_table *t, unsigned char c)
62{
63 unsigned char nc = t->charset2lower[c];
64
65 return nc ? nc : c;
66}
67
68static inline unsigned char nls_toupper(struct nls_table *t, unsigned char c)
69{
70 unsigned char nc = t->charset2upper[c];
71
72 return nc ? nc : c;
73}
74
75static inline int nls_strnicmp(struct nls_table *t, const unsigned char *s1,
76 const unsigned char *s2, int len)
77{
78 while (len--) {
79 if (nls_tolower(t, *s1++) != nls_tolower(t, *s2++))
80 return 1;
81 }
82
83 return 0;
84}
85
86/*
87 * nls_nullsize - return length of null character for codepage
88 * @codepage - codepage for which to return length of NULL terminator
89 *
90 * Since we can't guarantee that the null terminator will be a particular
91 * length, we have to check against the codepage. If there's a problem
92 * determining it, assume a single-byte NULL terminator.
93 */
94static inline int
95nls_nullsize(const struct nls_table *codepage)
96{
97 int charlen;
98 char tmp[NLS_MAX_CHARSET_SIZE];
99
100 charlen = codepage->uni2char(0, tmp, NLS_MAX_CHARSET_SIZE);
101
102 return charlen > 0 ? charlen : 1;
103}
104
105#define MODULE_ALIAS_NLS(name) MODULE_ALIAS("nls_" __stringify(name))
106
107#endif /* _LINUX_NLS_H */
108