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/kernel.h> 13 #include <linux/types.h> 14 15 #define MAX_UTF8_PER_UTF16 4 16 17 /** 18 * utf16_strlen() - Get the length of an utf16 string 19 * 20 * Returns the number of 16 bit characters in an utf16 string, not 21 * including the terminating NULL character. 22 * 23 * @in the string to measure 24 * @return the string length 25 */ 26 size_t utf16_strlen(const uint16_t *in); 27 28 /** 29 * utf16_strnlen() - Get the length of a fixed-size utf16 string. 30 * 31 * Returns the number of 16 bit characters in an utf16 string, 32 * not including the terminating NULL character, but at most 33 * 'count' number of characters. In doing this, utf16_strnlen() 34 * looks at only the first 'count' characters. 35 * 36 * @in the string to measure 37 * @count the maximum number of characters to count 38 * @return the string length, up to a maximum of 'count' 39 */ 40 size_t utf16_strnlen(const uint16_t *in, size_t count); 41 42 /** 43 * utf16_strcpy() - UTF16 equivalent of strcpy() 44 */ 45 uint16_t *utf16_strcpy(uint16_t *dest, const uint16_t *src); 46 47 /** 48 * utf16_strdup() - UTF16 equivalent of strdup() 49 */ 50 uint16_t *utf16_strdup(const uint16_t *s); 51 52 /** 53 * utf16_to_utf8() - Convert an utf16 string to utf8 54 * 55 * Converts 'size' characters of the utf16 string 'src' to utf8 56 * written to the 'dest' buffer. 57 * 58 * NOTE that a single utf16 character can generate up to 4 utf8 59 * characters. See MAX_UTF8_PER_UTF16. 60 * 61 * @dest the destination buffer to write the utf8 characters 62 * @src the source utf16 string 63 * @size the number of utf16 characters to convert 64 * @return the pointer to the first unwritten byte in 'dest' 65 */ 66 uint8_t *utf16_to_utf8(uint8_t *dest, const uint16_t *src, size_t size); 67 68 #endif /* __CHARSET_H_ */ 69