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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
12#define MAX_UTF8_PER_UTF16 4
13
14/**
15 * utf16_strlen() - Get the length of an utf16 string
16 *
17 * Returns the number of 16 bit characters in an utf16 string, not
18 * including the terminating NULL character.
19 *
20 * @in the string to measure
21 * @return the string length
22 */
23size_t utf16_strlen(const uint16_t *in);
24
25/**
26 * utf16_strnlen() - Get the length of a fixed-size utf16 string.
27 *
28 * Returns the number of 16 bit characters in an utf16 string,
29 * not including the terminating NULL character, but at most
30 * 'count' number of characters. In doing this, utf16_strnlen()
31 * looks at only the first 'count' characters.
32 *
33 * @in the string to measure
34 * @count the maximum number of characters to count
35 * @return the string length, up to a maximum of 'count'
36 */
37size_t utf16_strnlen(const uint16_t *in, size_t count);
38
39/**
40 * utf16_strcpy() - UTF16 equivalent of strcpy()
41 */
42uint16_t *utf16_strcpy(uint16_t *dest, const uint16_t *src);
43
44/**
45 * utf16_strdup() - UTF16 equivalent of strdup()
46 */
47uint16_t *utf16_strdup(const uint16_t *s);
48
49/**
50 * utf16_to_utf8() - Convert an utf16 string to utf8
51 *
52 * Converts 'size' characters of the utf16 string 'src' to utf8
53 * written to the 'dest' buffer.
54 *
55 * NOTE that a single utf16 character can generate up to 4 utf8
56 * characters. See MAX_UTF8_PER_UTF16.
57 *
58 * @dest the destination buffer to write the utf8 characters
59 * @src the source utf16 string
60 * @size the number of utf16 characters to convert
61 * @return the pointer to the first unwritten byte in 'dest'
62 */
63uint8_t *utf16_to_utf8(uint8_t *dest, const uint16_t *src, size_t size);
64
65#endif /* __CHARSET_H_ */