#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* wchar_t values is now outdated.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 *);
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);

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 */