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Rob Clark78178bb2017-09-09 06:47:40 -04001/*
2 * charset conversion utils
3 *
4 * Copyright (c) 2017 Rob Clark
5 *
6 * SPDX-License-Identifier: GPL-2.0+
7 */
8
9#ifndef __CHARSET_H_
10#define __CHARSET_H_
11
Heinrich Schuchardtf58c5ec2017-10-18 18:13:06 +020012#include <linux/types.h>
13
Heinrich Schuchardt984f2512017-10-09 21:09:05 +020014#define MAX_UTF8_PER_UTF16 3
Rob Clark78178bb2017-09-09 06:47:40 -040015
16/**
17 * utf16_strlen() - Get the length of an utf16 string
18 *
19 * Returns the number of 16 bit characters in an utf16 string, not
20 * including the terminating NULL character.
21 *
22 * @in the string to measure
23 * @return the string length
24 */
25size_t utf16_strlen(const uint16_t *in);
26
27/**
28 * utf16_strnlen() - Get the length of a fixed-size utf16 string.
29 *
30 * Returns the number of 16 bit characters in an utf16 string,
31 * not including the terminating NULL character, but at most
32 * 'count' number of characters. In doing this, utf16_strnlen()
33 * looks at only the first 'count' characters.
34 *
35 * @in the string to measure
36 * @count the maximum number of characters to count
37 * @return the string length, up to a maximum of 'count'
38 */
39size_t utf16_strnlen(const uint16_t *in, size_t count);
40
41/**
42 * utf16_strcpy() - UTF16 equivalent of strcpy()
43 */
44uint16_t *utf16_strcpy(uint16_t *dest, const uint16_t *src);
45
46/**
47 * utf16_strdup() - UTF16 equivalent of strdup()
48 */
49uint16_t *utf16_strdup(const uint16_t *s);
50
51/**
52 * utf16_to_utf8() - Convert an utf16 string to utf8
53 *
54 * Converts 'size' characters of the utf16 string 'src' to utf8
55 * written to the 'dest' buffer.
56 *
Heinrich Schuchardt984f2512017-10-09 21:09:05 +020057 * NOTE that a single utf16 character can generate up to 3 utf8
Rob Clark78178bb2017-09-09 06:47:40 -040058 * characters. See MAX_UTF8_PER_UTF16.
59 *
60 * @dest the destination buffer to write the utf8 characters
61 * @src the source utf16 string
62 * @size the number of utf16 characters to convert
63 * @return the pointer to the first unwritten byte in 'dest'
64 */
65uint8_t *utf16_to_utf8(uint8_t *dest, const uint16_t *src, size_t size);
66
Heinrich Schuchardtf58c5ec2017-10-18 18:13:06 +020067/**
68 * utf8_to_utf16() - Convert an utf8 string to utf16
69 *
70 * Converts up to 'size' characters of the utf16 string 'src' to utf8
71 * written to the 'dest' buffer. Stops at 0x00.
72 *
73 * @dest the destination buffer to write the utf8 characters
74 * @src the source utf16 string
75 * @size maximum number of utf16 characters to convert
76 * @return the pointer to the first unwritten byte in 'dest'
77 */
78uint16_t *utf8_to_utf16(uint16_t *dest, const uint8_t *src, size_t size);
79
Rob Clark78178bb2017-09-09 06:47:40 -040080#endif /* __CHARSET_H_ */