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74675a5850
This patch (as1239) updates the kernel's treatment of Unicode. The character-set conversion routines are well behind the current state of the Unicode specification: They don't recognize the existence of code points beyond plane 0 or of surrogate pairs in the UTF-16 encoding. The old wchar_t 16-bit type is retained because it's still used in lots of places. This shouldn't cause any new problems; if a conversion now results in an invalid 16-bit code then before it must have yielded an undefined code. Difficult-to-read names like "utf_mbstowcs" are replaced with more transparent names like "utf8s_to_utf16s" and the ordering of the parameters is rationalized (buffer lengths come immediate after the pointers they refer to, and the inputs precede the outputs). Fortunately the low-level conversion routines are used in only a few places; the interfaces to the higher-level uni2char and char2uni methods have been left unchanged. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Acked-by: Clemens Ladisch <clemens@ladisch.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
106 lines
2.9 KiB
C
106 lines
2.9 KiB
C
#ifndef _LINUX_NLS_H
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#define _LINUX_NLS_H
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#include <linux/init.h>
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/* Unicode has changed over the years. Unicode code points no longer
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* fit into 16 bits; as of Unicode 5 valid code points range from 0
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* to 0x10ffff (17 planes, where each plane holds 65536 code points).
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*
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* The original decision to represent Unicode characters as 16-bit
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* wchar_t values is now outdated. But plane 0 still includes the
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* most commonly used characters, so we will retain it. The newer
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* 32-bit unicode_t type can be used when it is necessary to
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* represent the full Unicode character set.
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*/
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/* Plane-0 Unicode character */
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typedef u16 wchar_t;
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#define MAX_WCHAR_T 0xffff
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/* Arbitrary Unicode character */
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typedef u32 unicode_t;
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struct nls_table {
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const char *charset;
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const char *alias;
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int (*uni2char) (wchar_t uni, unsigned char *out, int boundlen);
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int (*char2uni) (const unsigned char *rawstring, int boundlen,
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wchar_t *uni);
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const unsigned char *charset2lower;
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const unsigned char *charset2upper;
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struct module *owner;
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struct nls_table *next;
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};
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/* this value hold the maximum octet of charset */
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#define NLS_MAX_CHARSET_SIZE 6 /* for UTF-8 */
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/* Byte order for UTF-16 strings */
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enum utf16_endian {
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UTF16_HOST_ENDIAN,
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UTF16_LITTLE_ENDIAN,
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UTF16_BIG_ENDIAN
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};
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/* nls.c */
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extern int register_nls(struct nls_table *);
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extern int unregister_nls(struct nls_table *);
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extern struct nls_table *load_nls(char *);
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extern void unload_nls(struct nls_table *);
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extern struct nls_table *load_nls_default(void);
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extern int utf8_to_utf32(const u8 *s, int len, unicode_t *pu);
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extern int utf32_to_utf8(unicode_t u, u8 *s, int maxlen);
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extern int utf8s_to_utf16s(const u8 *s, int len, wchar_t *pwcs);
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extern int utf16s_to_utf8s(const wchar_t *pwcs, int len,
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enum utf16_endian endian, u8 *s, int maxlen);
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static inline unsigned char nls_tolower(struct nls_table *t, unsigned char c)
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{
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unsigned char nc = t->charset2lower[c];
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return nc ? nc : c;
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}
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static inline unsigned char nls_toupper(struct nls_table *t, unsigned char c)
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{
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unsigned char nc = t->charset2upper[c];
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return nc ? nc : c;
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}
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static inline int nls_strnicmp(struct nls_table *t, const unsigned char *s1,
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const unsigned char *s2, int len)
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{
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while (len--) {
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if (nls_tolower(t, *s1++) != nls_tolower(t, *s2++))
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return 1;
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}
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return 0;
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}
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/*
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* nls_nullsize - return length of null character for codepage
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* @codepage - codepage for which to return length of NULL terminator
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*
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* Since we can't guarantee that the null terminator will be a particular
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* length, we have to check against the codepage. If there's a problem
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* determining it, assume a single-byte NULL terminator.
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*/
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static inline int
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nls_nullsize(const struct nls_table *codepage)
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{
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int charlen;
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char tmp[NLS_MAX_CHARSET_SIZE];
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charlen = codepage->uni2char(0, tmp, NLS_MAX_CHARSET_SIZE);
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return charlen > 0 ? charlen : 1;
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}
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#define MODULE_ALIAS_NLS(name) MODULE_ALIAS("nls_" __stringify(name))
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#endif /* _LINUX_NLS_H */
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