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diff --git a/include/charset.h b/include/charset.h
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+++ b/include/charset.h
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+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ *  charset conversion utils
+ *
+ *  Copyright (c) 2017 Rob Clark
+ */
+
+#ifndef __CHARSET_H_
+#define __CHARSET_H_
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+
+#define MAX_UTF8_PER_UTF16 3
+
+/**
+ * console_read_unicode() - read Unicode code point from console
+ *
+ * @code:	pointer to store Unicode code point
+ * Return:	0 = success
+ */
+int console_read_unicode(s32 *code);
+
+/**
+ * utf8_get() - get next UTF-8 code point from buffer
+ *
+ * @src:		pointer to current byte, updated to point to next byte
+ * Return:		code point, or 0 for end of string, or -1 if no legal
+ *			code point is found. In case of an error src points to
+ *			the incorrect byte.
+ */
+s32 utf8_get(const char **src);
+
+/**
+ * utf8_put() - write UTF-8 code point to buffer
+ *
+ * @code:		code point
+ * @dst:		pointer to destination buffer, updated to next position
+ * Return:		-1 if the input parameters are invalid
+ */
+int utf8_put(s32 code, char **dst);
+
+/**
+ * utf8_utf16_strnlen() - length of a truncated utf-8 string after conversion
+ *			  to utf-16
+ *
+ * @src:		utf-8 string
+ * @count:		maximum number of code points to convert
+ * Return:		length in u16 after conversion to utf-16 without the
+ *			trailing \0. If an invalid UTF-8 sequence is hit one
+ *			u16 will be reserved for a replacement character.
+ */
+size_t utf8_utf16_strnlen(const char *src, size_t count);
+
+/**
+ * utf8_utf16_strlen() - length of a utf-8 string after conversion to utf-16
+ *
+ * @src:		utf-8 string
+ * Return:		length in u16 after conversion to utf-16 without the
+ *			trailing \0. If an invalid UTF-8 sequence is hit one
+ *			u16 will be reserved for a replacement character.
+ */
+#define utf8_utf16_strlen(a) utf8_utf16_strnlen((a), SIZE_MAX)
+
+/**
+ * utf8_utf16_strncpy() - copy utf-8 string to utf-16 string
+ *
+ * @dst:		destination buffer
+ * @src:		source buffer
+ * @count:		maximum number of code points to copy
+ * Return:		-1 if the input parameters are invalid
+ */
+int utf8_utf16_strncpy(u16 **dst, const char *src, size_t count);
+
+/**
+ * utf8_utf16_strcpy() - copy utf-8 string to utf-16 string
+ *
+ * @dst:		destination buffer
+ * @src:		source buffer
+ * Return:		-1 if the input parameters are invalid
+ */
+#define utf8_utf16_strcpy(d, s) utf8_utf16_strncpy((d), (s), SIZE_MAX)
+
+/**
+ * utf16_get() - get next UTF-16 code point from buffer
+ *
+ * @src:		pointer to current word, updated to point to next word
+ * Return:		code point, or 0 for end of string, or -1 if no legal
+ *			code point is found. In case of an error src points to
+ *			the incorrect word.
+ */
+s32 utf16_get(const u16 **src);
+
+/**
+ * utf16_put() - write UTF-16 code point to buffer
+ *
+ * @code:		code point
+ * @dst:		pointer to destination buffer, updated to next position
+ * Return:		-1 if the input parameters are invalid
+ */
+int utf16_put(s32 code, u16 **dst);
+
+/**
+ * utf16_strnlen() - length of a truncated utf-16 string
+ *
+ * @src:		utf-16 string
+ * @count:		maximum number of code points to convert
+ * Return:		length in code points. If an invalid UTF-16 sequence is
+ *			hit one position will be reserved for a replacement
+ *			character.
+ */
+size_t utf16_strnlen(const u16 *src, size_t count);
+
+/**
+ * utf16_utf8_strnlen() - length of a truncated utf-16 string after conversion
+ *			  to utf-8
+ *
+ * @src:		utf-16 string
+ * @count:		maximum number of code points to convert
+ * Return:		length in bytes after conversion to utf-8 without the
+ *			trailing \0. If an invalid UTF-16 sequence is hit one
+ *			byte will be reserved for a replacement character.
+ */
+size_t utf16_utf8_strnlen(const u16 *src, size_t count);
+
+/**
+ * utf16_utf8_strlen() - length of a utf-16 string after conversion to utf-8
+ *
+ * @src:		utf-16 string
+ * Return:		length in bytes after conversion to utf-8 without the
+ *			trailing \0. If an invalid UTF-16 sequence is hit one
+ *			byte will be reserved for a replacement character.
+ */
+#define utf16_utf8_strlen(a) utf16_utf8_strnlen((a), SIZE_MAX)
+
+/**
+ * utf16_utf8_strncpy() - copy utf-16 string to utf-8 string
+ *
+ * @dst:		destination buffer
+ * @src:		source buffer
+ * @count:		maximum number of code points to copy
+ * Return:		-1 if the input parameters are invalid
+ */
+int utf16_utf8_strncpy(char **dst, const u16 *src, size_t count);
+
+/**
+ * utf16_utf8_strcpy() - copy utf-16 string to utf-8 string
+ *
+ * @dst:		destination buffer
+ * @src:		source buffer
+ * Return:		-1 if the input parameters are invalid
+ */
+#define utf16_utf8_strcpy(d, s) utf16_utf8_strncpy((d), (s), SIZE_MAX)
+
+/**
+ * utf_to_lower() - convert a Unicode letter to lower case
+ *
+ * @code:		letter to convert
+ * Return:		lower case letter or unchanged letter
+ */
+s32 utf_to_lower(const s32 code);
+
+/**
+ * utf_to_upper() - convert a Unicode letter to upper case
+ *
+ * @code:		letter to convert
+ * Return:		upper case letter or unchanged letter
+ */
+s32 utf_to_upper(const s32 code);
+
+/*
+ * u16_strncmp() - compare two u16 string
+ *
+ * @s1:		first string to compare
+ * @s2:		second string to compare
+ * @n:		maximum number of u16 to compare
+ * Return:	0  if the first n u16 are the same in s1 and s2
+ *		< 0 if the first different u16 in s1 is less than the
+ *		corresponding u16 in s2
+ *		> 0 if the first different u16 in s1 is greater than the
+ *		corresponding u16 in s2
+ */
+int u16_strncmp(const u16 *s1, const u16 *s2, size_t n);
+#define u16_strcmp(s1, s2)	u16_strncmp((s1), (s2), SIZE_MAX)
+
+/**
+ * u16_strlen - count non-zero words
+ *
+ * This function matches wsclen() if the -fshort-wchar compiler flag is set.
+ * In the EFI context we explicitly need a function handling u16 strings.
+ *
+ * @in:			null terminated u16 string
+ * ReturnValue:		number of non-zero words.
+ *			This is not the number of utf-16 letters!
+ */
+size_t u16_strlen(const void *in);
+
+/**
+ * u16_strlen - count non-zero words
+ *
+ * This function matches wscnlen_s() if the -fshort-wchar compiler flag is set.
+ * In the EFI context we explicitly need a function handling u16 strings.
+ *
+ * @in:			null terminated u16 string
+ * @count:		maximum number of words to count
+ * ReturnValue:		number of non-zero words.
+ *			This is not the number of utf-16 letters!
+ */
+size_t u16_strnlen(const u16 *in, size_t count);
+
+/**
+ * u16_strcpy() - copy u16 string
+ *
+ * Copy u16 string pointed to by src, including terminating null word, to
+ * the buffer pointed to by dest.
+ *
+ * @dest:		destination buffer
+ * @src:		source buffer (null terminated)
+ * Return:		'dest' address
+ */
+u16 *u16_strcpy(u16 *dest, const u16 *src);
+
+/**
+ * u16_strdup() - duplicate u16 string
+ *
+ * Copy u16 string pointed to by src, including terminating null word, to a
+ * newly allocated buffer.
+ *
+ * @src:		source buffer (null terminated)
+ * Return:		allocated new buffer on success, NULL on failure
+ */
+u16 *u16_strdup(const void *src);
+
+/**
+ * utf16_to_utf8() - Convert an utf16 string to utf8
+ *
+ * Converts 'size' characters of the utf16 string 'src' to utf8
+ * written to the 'dest' buffer.
+ *
+ * NOTE that a single utf16 character can generate up to 3 utf8
+ * characters.  See MAX_UTF8_PER_UTF16.
+ *
+ * @dest   the destination buffer to write the utf8 characters
+ * @src    the source utf16 string
+ * @size   the number of utf16 characters to convert
+ * @return the pointer to the first unwritten byte in 'dest'
+ */
+uint8_t *utf16_to_utf8(uint8_t *dest, const uint16_t *src, size_t size);
+
+#endif /* __CHARSET_H_ */