UCONV_U16TOU32(3C)UCONV_U16TOU32(3C)NAME
uconv_u16tou32, uconv_u16tou8, uconv_u32tou16, uconv_u32tou8,
uconv_u8tou16, uconv_u8tou32 - Unicode encoding conversion functions
SYNOPSIS
#include <sys/types.h>
#include <sys/errno.h>
#include <sys/u8_textprep.h>
int uconv_u16tou32(const uint16_t *utf16str, size_t *utf16len,
uint32_t *utf32str, size_t *utf32len, int flag);
int uconv_u16tou8(const uint16_t *utf16str, size_t *utf16len,
uchar_t *utf8str, size_t *utf8len, int flag);
int uconv_u32tou16(const uint32_t *utf32str, size_t *utf32len,
uint16_t *utf16str, size_t *utf16len, int flag);
int uconv_u32tou8(const uint32_t *utf32str, size_t *utf32len,
uchar_t *utf8str, size_t *utf8len, int flag);
int uconv_u8tou16(const uchar_t *utf8str, size_t *utf8len,
uint16_t *utf16str, size_t *utf16len, int flag);
int uconv_u8tou32(const uchar_t *utf8str, size_t *utf8len,
uint32_t *utf32str, size_t *utf32len, int flag);
PARAMETERS
utf16str
A pointer to a UTF-16 character string.
utf16len
As an input parameter, the number of 16-bit unsigned inte‐
gers in utf16str as UTF-16 characters to be converted or
saved.
As an output parameter, the number of 16-bit unsigned inte‐
gers in utf16str consumed or saved during conversion.
utf32str
A pointer to a UTF-32 character string.
utf32len
As an input parameter, the number of 32-bit unsigned inte‐
gers in utf32str as UTF-32 characters to be converted or
saved.
As an output parameter, the number of 32-bit unsigned inte‐
gers in utf32str consumed or saved during conversion.
utf8str
A pointer to a UTF-8 character string.
utf8len
As an input parameter, the number of bytes in utf8str as
UTF-8 characters to be converted or saved.
As an output parameter, the number of bytes in utf8str con‐
sumed or saved during conversion.
flag
The possible conversion options that are constructed by a
bitwise-inclusive-OR of the following values:
UCONV_IN_BIG_ENDIAN
The input parameter is in big endian byte ordering.
UCONV_OUT_BIG_ENDIAN
The output parameter should be in big endian byte
ordering.
UCONV_IN_SYSTEM_ENDIAN
The input parameter is in the default byte ordering of
the current system.
UCONV_OUT_SYSTEM_ENDIAN
The output parameter should be in the default byte
ordering of the current system.
UCONV_IN_LITTLE_ENDIAN
The input parameter is in little endian byte ordering.
UCONV_OUT_LITTLE_ENDIAN
The output parameter should be in little endian byte
ordering.
UCONV_IGNORE_NULL
The null or U+0000 character should not stop the con‐
version.
UCONV_IN_ACCEPT_BOM
If the Byte Order Mark (BOM, U+FEFF) character exists
as the first character of the input parameter, inter‐
pret it as the BOM character.
UCONV_OUT_EMIT_BOM
Start the output parameter with Byte Order Mark (BOM,
U+FEFF) character to indicate the byte ordering if the
output parameter is in UTF-16 or UTF-32.
DESCRIPTION
The uconv_u16tou32() function reads the given utf16str in UTF-16 until
U+0000 (zero) in utf16str is encountered as a character or until the
number of 16-bit unsigned integers specified in utf16len is read. The
UTF-16 characters that are read are converted into UTF-32 and the
result is saved at utf32str. After the successful conversion, utf32len
contains the number of 32-bit unsigned integers saved at utf32str as
UTF-32 characters.
The uconv_u16tou8() function reads the given utf16str in UTF-16 until
U+0000 (zero) in utf16str is encountered as a character or until the
number of 16-bit unsigned integers specified in utf16len is read. The
UTF-16 characters that are read are converted into UTF-8 and the result
is saved at utf8str. After the successful conversion, utf8len contains
the number of bytes saved at utf8str as UTF-8 characters.
The uconv_u32tou16() function reads the given utf32str in UTF-32 until
U+0000 (zero) in utf32str is encountered as a character or until the
number of 32-bit unsigned integers specified in utf32len is read. The
UTF-32 characters that are read are converted into UTF-16 and the
result is saved at utf16str. After the successful conversion, utf16len
contains the number of 16-bit unsigned integers saved at utf16str as
UTF-16 characters.
The uconv_u32tou8() function reads the given utf32str in UTF-32 until
U+0000 (zero) in utf32str is encountered as a character or until the
number of 32-bit unsigned integers specified in utf32len is read. The
UTF-32 characters that are read are converted into UTF-8 and the result
is saved at utf8str. After the successful conversion, utf8len contains
the number of bytes saved at utf8str as UTF-8 characters.
The uconv_u8tou16() function reads the given utf8str in UTF-8 until the
null ('\0') byte in utf8str is encountered or until the number of bytes
specified in utf8len is read. The UTF-8 characters that are read are
converted into UTF-16 and the result is saved at utf16str. After the
successful conversion, utf16len contains the number of 16-bit unsigned
integers saved at utf16str as UTF-16 characters.
The uconv_u8tou32() function reads the given utf8str in UTF-8 until the
null ('\0') byte in utf8str is encountered or until the number of bytes
specified in utf8len is read. The UTF-8 characters that are read are
converted into UTF-32 and the result is saved at utf32str. After the
successful conversion, utf32len contains the number of 32-bit unsigned
integers saved at utf32str as UTF-32 characters.
During the conversion, the input and the output parameters are treated
with byte orderings specified in the flag parameter. When not speci‐
fied, the default byte ordering of the system is used. The byte order‐
ing flag value that is specified for UTF-8 is ignored.
When UCONV_IN_ACCEPT_BOM is specified as the flag and the first charac‐
ter of the string pointed to by the input parameter is the BOM charac‐
ter, the value of the BOM character dictates the byte ordering of the
subsequent characters in the string pointed to by the input parameter,
regardless of the supplied input parameter byte ordering option flag
values. If the UCONV_IN_ACCEPT_BOM is not specified, the BOM as the
first character is treated as a regular Unicode character: Zero Width
No Break Space (ZWNBSP) character.
When UCONV_IGNORE_NULL is specified, regardless of whether the input
parameter contains U+0000 or null byte, the conversion continues until
the specified number of input parameter elements at utf16len, utf32len,
or utf8len are entirely consumed during the conversion.
As output parameters, utf16len, utf32len, and utf8len are not changed
if conversion fails for any reason.
RETURN VALUES
Upon successful conversion, the functions return 0. Upon failure, the
functions return one of the following errno values:
EILSEQ
The conversion detected an illegal or out of bound character
value in the input parameter.
E2BIG
The conversion cannot finish because the size specified in
the output parameter is too small.
EINVAL
The conversion stops due to an incomplete character at the
end of the input string.
EBADF
Conflicting byte-ordering option flag values are detected.
EXAMPLES
Example 1 Convert a UTF-16 string in little-endian byte ordering into
UTF-8 string.
#include <sys/types.h>
#include <sys/errno.h>
#include <sys/u8_textprep.h>
.
.
.
uint16_t u16s[MAXNAMELEN + 1];
uchar_t u8s[MAXNAMELEN + 1];
size_t u16len, u8len;
int ret;
.
.
.
u16len = u8len = MAXNAMELEN;
ret = uconv_u16tou8(u16s, &u16len, u8s, &u8len,
UCONV_IN_LITTLE_ENDIAN);
if (ret != 0) {
/* Conversion error occurred. */
return (ret);
}
.
.
.
Example 2 Convert a UTF-32 string in big endian byte ordering into lit‐
tle endian UTF-16.
#include <sys/types.h>
#include <sys/errno.h>
#include <sys/u8_textprep.h>
.
.
.
/*
* An UTF-32 character can be mapped to an UTF-16 character with
* two 16-bit integer entities as a "surrogate pair."
*/
uint32_t u32s[101];
uint16_t u16s[101];
int ret;
size_t u32len, u16len;
.
.
.
u32len = u16len = 100;
ret = uconv_u32tou16(u32s, &u32len, u16s, &u16len,
UCONV_IN_BIG_ENDIAN | UCONV_OUT_LITTLE_ENDIAN);
if (ret == 0) {
return (0);
} else if (ret == E2BIG) {
/* Use bigger output parameter and try just one more time. */
uint16_t u16s2[201];
u16len = 200;
ret = uconv_u32tou16(u32s, &u32len, u16s2, &u16len,
UCONV_IN_BIG_ENDIAN | UCONV_OUT_LITTLE_ENDIAN);
if (ret == 0)
return (0);
}
/* Otherwise, return -1 to indicate an error condition. */
return (-1);
Example 3 Convert a UTF-8 string into UTF-16 in little-endian byte
ordering.
Convert a UTF-8 string into UTF-16 in little-endian byte ordering with
a Byte Order Mark (BOM) character at the beginning of the output param‐
eter.
#include <sys/types.h>
#include <sys/errno.h>
#include <sys/u8_textprep>
.
.
.
uchar_t u8s[MAXNAMELEN + 1];
uint16_t u16s[MAXNAMELEN + 1];
size_t u8len, u16len;
int ret;
.
.
.
u8len = u16len = MAXNAMELEN;
ret = uconv_u8tou16(u8s, &u8len, u16s, &u16len,
UCONV_IN_LITTLE_ENDIAN | UCONV_EMIT_BOM);
if (ret != 0) {
/* Conversion error occurred. */
return (ret);
}
.
.
.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌────────────────────┬─────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├────────────────────┼─────────────────┤
│Interface Stability │ Committed │
├────────────────────┼─────────────────┤
│MT-Level │ MT-Safe │
└────────────────────┴─────────────────┘
SEE ALSOattributes(5), uconv_u16tou32(9F)
The Unicode Standard (http://www.unicode.org)
NOTES
Each UTF-16 or UTF-32 character maps to an UTF-8 character that might
need one to maximum of four bytes.
One UTF-32 or UTF-8 character can yield two 16-bit unsigned integers as
a UTF-16 character, which is a surrogate pair if the Unicode scalar
value is bigger than U+FFFF.
Ill-formed UTF-16 surrogate pairs are seen as illegal characters during
the conversion.
Sep 18, 2007 UCONV_U16TOU32(3C)
