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Diffstat (limited to 'include/linux/nls.h')
-rw-r--r-- | include/linux/nls.h | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/include/linux/nls.h b/include/linux/nls.h new file mode 100644 index 000000000..520681b68 --- /dev/null +++ b/include/linux/nls.h @@ -0,0 +1,108 @@ +#ifndef _LINUX_NLS_H +#define _LINUX_NLS_H + +#include <linux/init.h> + +/* Unicode has changed over the years. Unicode code points no longer + * fit into 16 bits; as of Unicode 5 valid code points range from 0 + * to 0x10ffff (17 planes, where each plane holds 65536 code points). + * + * The original decision to represent Unicode characters as 16-bit + * wchar_t values is now outdated. But plane 0 still includes the + * most commonly used characters, so we will retain it. The newer + * 32-bit unicode_t type can be used when it is necessary to + * represent the full Unicode character set. + */ + +/* Plane-0 Unicode character */ +typedef u16 wchar_t; +#define MAX_WCHAR_T 0xffff + +/* Arbitrary Unicode character */ +typedef u32 unicode_t; + +struct nls_table { + const char *charset; + const char *alias; + int (*uni2char) (wchar_t uni, unsigned char *out, int boundlen); + int (*char2uni) (const unsigned char *rawstring, int boundlen, + wchar_t *uni); + const unsigned char *charset2lower; + const unsigned char *charset2upper; + struct module *owner; + struct nls_table *next; +}; + +/* this value hold the maximum octet of charset */ +#define NLS_MAX_CHARSET_SIZE 6 /* for UTF-8 */ + +/* Byte order for UTF-16 strings */ +enum utf16_endian { + UTF16_HOST_ENDIAN, + UTF16_LITTLE_ENDIAN, + UTF16_BIG_ENDIAN +}; + +/* nls_base.c */ +extern int __register_nls(struct nls_table *, struct module *); +extern int unregister_nls(struct nls_table *); +extern struct nls_table *load_nls(char *); +extern void unload_nls(struct nls_table *); +extern struct nls_table *load_nls_default(void); +#define register_nls(nls) __register_nls((nls), THIS_MODULE) + +extern int utf8_to_utf32(const u8 *s, int len, unicode_t *pu); +extern int utf32_to_utf8(unicode_t u, u8 *s, int maxlen); +extern int utf8s_to_utf16s(const u8 *s, int len, + enum utf16_endian endian, wchar_t *pwcs, int maxlen); +extern int utf16s_to_utf8s(const wchar_t *pwcs, int len, + enum utf16_endian endian, u8 *s, int maxlen); + +static inline unsigned char nls_tolower(struct nls_table *t, unsigned char c) +{ + unsigned char nc = t->charset2lower[c]; + + return nc ? nc : c; +} + +static inline unsigned char nls_toupper(struct nls_table *t, unsigned char c) +{ + unsigned char nc = t->charset2upper[c]; + + return nc ? nc : c; +} + +static inline int nls_strnicmp(struct nls_table *t, const unsigned char *s1, + const unsigned char *s2, int len) +{ + while (len--) { + if (nls_tolower(t, *s1++) != nls_tolower(t, *s2++)) + return 1; + } + + return 0; +} + +/* + * nls_nullsize - return length of null character for codepage + * @codepage - codepage for which to return length of NULL terminator + * + * Since we can't guarantee that the null terminator will be a particular + * length, we have to check against the codepage. If there's a problem + * determining it, assume a single-byte NULL terminator. + */ +static inline int +nls_nullsize(const struct nls_table *codepage) +{ + int charlen; + char tmp[NLS_MAX_CHARSET_SIZE]; + + charlen = codepage->uni2char(0, tmp, NLS_MAX_CHARSET_SIZE); + + return charlen > 0 ? charlen : 1; +} + +#define MODULE_ALIAS_NLS(name) MODULE_ALIAS("nls_" __stringify(name)) + +#endif /* _LINUX_NLS_H */ + |