1 files changed, 109 insertions, 0 deletions
diff --git a/include/linux/nls.h b/include/linux/nls.h
new file mode 100644
index 000000000..e0bf8367b
--- /dev/null
+++ b/include/linux/nls.h
@@ -0,0 +1,109 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#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+ * wchar_t values is now outdated.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(const char *charset);
+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 */
+