1 /* SPDX-License-Identifier: GPL-2.0+ */ 2 /* 3 * charset conversion utils 4 * 5 * Copyright (c) 2017 Rob Clark 6 */ 7 8 #ifndef __CHARSET_H_ 9 #define __CHARSET_H_ 10 11 #include <linux/types.h> 12 13 #define MAX_UTF8_PER_UTF16 3 14 15 /** 16 * utf16_strlen() - Get the length of an utf16 string 17 * 18 * Returns the number of 16 bit characters in an utf16 string, not 19 * including the terminating NULL character. 20 * 21 * @in the string to measure 22 * @return the string length 23 */ 24 size_t utf16_strlen(const uint16_t *in); 25 26 /** 27 * utf16_strnlen() - Get the length of a fixed-size utf16 string. 28 * 29 * Returns the number of 16 bit characters in an utf16 string, 30 * not including the terminating NULL character, but at most 31 * 'count' number of characters. In doing this, utf16_strnlen() 32 * looks at only the first 'count' characters. 33 * 34 * @in the string to measure 35 * @count the maximum number of characters to count 36 * @return the string length, up to a maximum of 'count' 37 */ 38 size_t utf16_strnlen(const uint16_t *in, size_t count); 39 40 /** 41 * utf16_strcpy() - UTF16 equivalent of strcpy() 42 */ 43 uint16_t *utf16_strcpy(uint16_t *dest, const uint16_t *src); 44 45 /** 46 * utf16_strdup() - UTF16 equivalent of strdup() 47 */ 48 uint16_t *utf16_strdup(const uint16_t *s); 49 50 /** 51 * utf16_to_utf8() - Convert an utf16 string to utf8 52 * 53 * Converts 'size' characters of the utf16 string 'src' to utf8 54 * written to the 'dest' buffer. 55 * 56 * NOTE that a single utf16 character can generate up to 3 utf8 57 * characters. See MAX_UTF8_PER_UTF16. 58 * 59 * @dest the destination buffer to write the utf8 characters 60 * @src the source utf16 string 61 * @size the number of utf16 characters to convert 62 * @return the pointer to the first unwritten byte in 'dest' 63 */ 64 uint8_t *utf16_to_utf8(uint8_t *dest, const uint16_t *src, size_t size); 65 66 /** 67 * utf8_to_utf16() - Convert an utf8 string to utf16 68 * 69 * Converts up to 'size' characters of the utf16 string 'src' to utf8 70 * written to the 'dest' buffer. Stops at 0x00. 71 * 72 * @dest the destination buffer to write the utf8 characters 73 * @src the source utf16 string 74 * @size maximum number of utf16 characters to convert 75 * @return the pointer to the first unwritten byte in 'dest' 76 */ 77 uint16_t *utf8_to_utf16(uint16_t *dest, const uint8_t *src, size_t size); 78 79 #endif /* __CHARSET_H_ */ 80