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