include/linux/nls.h

   1 #ifndef _LINUX_NLS_H
   2 #define _LINUX_NLS_H
   3
   4 #include <linux/init.h>
   5
   6 /* unicode character */
   7 typedef __u16 wchar_t;
   8
   9 struct nls_table {
  10         const char *charset;
  11         const char *alias;
  12         int (*uni2char) (wchar_t uni, unsigned char *out, int boundlen);
  13         int (*char2uni) (const unsigned char *rawstring, int boundlen,
  14                          wchar_t *uni);
  15         const unsigned char *charset2lower;
  16         const unsigned char *charset2upper;
  17         struct module *owner;
  18         struct nls_table *next;
  19 };
  20
  21 /* this value hold the maximum octet of charset */
  22 #define NLS_MAX_CHARSET_SIZE 6 /* for UTF-8 */
  23
  24 /* nls.c */
  25 extern int register_nls(struct nls_table *);
  26 extern int unregister_nls(struct nls_table *);
  27 extern struct nls_table *load_nls(char *);
  28 extern void unload_nls(struct nls_table *);
  29 extern struct nls_table *load_nls_default(void);
  30
  31 extern int utf8_mbtowc(wchar_t *, const __u8 *, int);
  32 extern int utf8_mbstowcs(wchar_t *, const __u8 *, int);
  33 extern int utf8_wctomb(__u8 *, wchar_t, int);
  34 extern int utf8_wcstombs(__u8 *, const wchar_t *, int);
  35
  36 static inline unsigned char nls_tolower(struct nls_table *t, unsigned char c)
  37 {
  38         unsigned char nc = t->charset2lower[c];
  39
  40         return nc ? nc : c;
  41 }
  42
  43 static inline unsigned char nls_toupper(struct nls_table *t, unsigned char c)
  44 {
  45         unsigned char nc = t->charset2upper[c];
  46
  47         return nc ? nc : c;
  48 }
  49
  50 static inline int nls_strnicmp(struct nls_table *t, const unsigned char *s1,
  51                 const unsigned char *s2, int len)
  52 {
  53         while (len--) {
  54                 if (nls_tolower(t, *s1++) != nls_tolower(t, *s2++))
  55                         return 1;
  56         }
  57
  58         return 0;
  59 }
  60
  61 /*
  62  * nls_nullsize - return length of null character for codepage
  63  * @codepage - codepage for which to return length of NULL terminator
  64  *
  65  * Since we can't guarantee that the null terminator will be a particular
  66  * length, we have to check against the codepage. If there's a problem
  67  * determining it, assume a single-byte NULL terminator.
  68  */
  69 static inline int
  70 nls_nullsize(const struct nls_table *codepage)
  71 {
  72         int charlen;
  73         char tmp[NLS_MAX_CHARSET_SIZE];
  74
  75         charlen = codepage->uni2char(0, tmp, NLS_MAX_CHARSET_SIZE);
  76
  77         return charlen > 0 ? charlen : 1;
  78 }
  79
  80 #define MODULE_ALIAS_NLS(name)  MODULE_ALIAS("nls_" __stringify(name))
  81
  82 #endif /* _LINUX_NLS_H */
  83