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1/* SPDX-License-Identifier: GPL-2.0 */2#ifndef _LINUX_NLS_H3#define _LINUX_NLS_H4 5#include <linux/init.h>6 7/* Unicode has changed over the years. Unicode code points no longer8 * fit into 16 bits; as of Unicode 5 valid code points range from 09 * to 0x10ffff (17 planes, where each plane holds 65536 code points).10 *11 * The original decision to represent Unicode characters as 16-bit12 * wchar_t values is now outdated. But plane 0 still includes the13 * most commonly used characters, so we will retain it. The newer14 * 32-bit unicode_t type can be used when it is necessary to15 * represent the full Unicode character set.16 */17 18/* Plane-0 Unicode character */19typedef u16 wchar_t;20#define MAX_WCHAR_T 0xffff21 22/* Arbitrary Unicode character */23typedef u32 unicode_t;24 25struct nls_table {26 const char *charset;27 const char *alias;28 int (*uni2char) (wchar_t uni, unsigned char *out, int boundlen);29 int (*char2uni) (const unsigned char *rawstring, int boundlen,30 wchar_t *uni);31 const unsigned char *charset2lower;32 const unsigned char *charset2upper;33 struct module *owner;34 struct nls_table *next;35};36 37/* this value hold the maximum octet of charset */38#define NLS_MAX_CHARSET_SIZE 6 /* for UTF-8 */39 40/* Byte order for UTF-16 strings */41enum utf16_endian {42 UTF16_HOST_ENDIAN,43 UTF16_LITTLE_ENDIAN,44 UTF16_BIG_ENDIAN45};46 47/* nls_base.c */48extern int __register_nls(struct nls_table *, struct module *);49extern int unregister_nls(struct nls_table *);50extern struct nls_table *load_nls(const char *charset);51extern void unload_nls(struct nls_table *);52extern struct nls_table *load_nls_default(void);53#define register_nls(nls) __register_nls((nls), THIS_MODULE)54 55extern int utf8_to_utf32(const u8 *s, int len, unicode_t *pu);56extern int utf32_to_utf8(unicode_t u, u8 *s, int maxlen);57extern int utf8s_to_utf16s(const u8 *s, int len,58 enum utf16_endian endian, wchar_t *pwcs, int maxlen);59extern int utf16s_to_utf8s(const wchar_t *pwcs, int len,60 enum utf16_endian endian, u8 *s, int maxlen);61 62static inline unsigned char nls_tolower(struct nls_table *t, unsigned char c)63{64 unsigned char nc = t->charset2lower[c];65 66 return nc ? nc : c;67}68 69static inline unsigned char nls_toupper(struct nls_table *t, unsigned char c)70{71 unsigned char nc = t->charset2upper[c];72 73 return nc ? nc : c;74}75 76static inline int nls_strnicmp(struct nls_table *t, const unsigned char *s1,77 const unsigned char *s2, int len)78{79 while (len--) {80 if (nls_tolower(t, *s1++) != nls_tolower(t, *s2++))81 return 1;82 }83 84 return 0;85}86 87/*88 * nls_nullsize - return length of null character for codepage89 * @codepage - codepage for which to return length of NULL terminator90 *91 * Since we can't guarantee that the null terminator will be a particular92 * length, we have to check against the codepage. If there's a problem93 * determining it, assume a single-byte NULL terminator.94 */95static inline int96nls_nullsize(const struct nls_table *codepage)97{98 int charlen;99 char tmp[NLS_MAX_CHARSET_SIZE];100 101 charlen = codepage->uni2char(0, tmp, NLS_MAX_CHARSET_SIZE);102 103 return charlen > 0 ? charlen : 1;104}105 106#define MODULE_ALIAS_NLS(name) MODULE_ALIAS("nls_" __stringify(name))107 108#endif /* _LINUX_NLS_H */109 110