xref: /openbmc/u-boot/include/charset.h (revision af104ae5)
1 /*
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 #include <linux/types.h>
13 
14 #define MAX_UTF8_PER_UTF16 3
15 
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  */
25 size_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  */
39 size_t utf16_strnlen(const uint16_t *in, size_t count);
40 
41 /**
42  * utf16_strcpy() - UTF16 equivalent of strcpy()
43  */
44 uint16_t *utf16_strcpy(uint16_t *dest, const uint16_t *src);
45 
46 /**
47  * utf16_strdup() - UTF16 equivalent of strdup()
48  */
49 uint16_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  *
57  * NOTE that a single utf16 character can generate up to 3 utf8
58  * 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  */
65 uint8_t *utf16_to_utf8(uint8_t *dest, const uint16_t *src, size_t size);
66 
67 /**
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  */
78 uint16_t *utf8_to_utf16(uint16_t *dest, const uint8_t *src, size_t size);
79 
80 #endif /* __CHARSET_H_ */
81