include/charset.h

   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 #define MAX_UTF8_PER_UTF16 3
  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  */
  23 size_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  */
  37 size_t utf16_strnlen(const uint16_t *in, size_t count);
  38
  39 /**
  40  * utf16_strcpy() - UTF16 equivalent of strcpy()
  41  */
  42 uint16_t *utf16_strcpy(uint16_t *dest, const uint16_t *src);
  43
  44 /**
  45  * utf16_strdup() - UTF16 equivalent of strdup()
  46  */
  47 uint16_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 3 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  */
  63 uint8_t *utf16_to_utf8(uint8_t *dest, const uint16_t *src, size_t size);
  64
  65 #endif /* __CHARSET_H_ */