illumos: manual page: u8_textprep

U8_TEXTPREP_STR(3C) Standard C Library Functions U8_TEXTPREP_STR(3C)

NAME

u8_textprep_str - string-based UTF-8 text preparation function

SYNOPSIS

#include <sys/u8_textprep.h>

size_t u8_textprep_str(char *inarray, size_t *inlen,
char *outarray, size_t *outlen, int flag,
size_t unicode_version, int *errnum);

PARAMETERS

inarray
A pointer to a byte array containing a sequence of
UTF-8 character bytes to be prepared.

inlen
As input argument, the number of bytes to be prepared
in inarray. As output argument, the number of bytes
in inarray still not consumed.

outarray
A pointer to a byte array where prepared UTF-8
character bytes can be saved.

outlen
As input argument, the number of available bytes at
outarray where prepared character bytes can be saved.
As output argument, after the conversion, the number
of bytes still available at outarray.

flag
The possible preparation options constructed by a
bitwise-inclusive-OR of the following values:

U8_TEXTPREP_IGNORE_NULL

Normally u8_textprep_str() stops the preparation
if it encounters null byte even if the current
inlen is pointing to a value bigger than zero.

With this option, null byte does not stop the
preparation and the preparation continues until
inlen specified amount of inarray bytes are all
consumed for preparation or an error happened.

U8_TEXTPREP_IGNORE_INVALID

Normally u8_textprep_str() stops the preparation
if it encounters illegal or incomplete characters
with corresponding errnum values.

When this option is set, u8_textprep_str() does
not stop the preparation and instead treats such
characters as no need to do any preparation.

U8_TEXTPREP_TOUPPER

Map lowercase characters to uppercase characters
if applicable.

U8_TEXTPREP_TOLOWER

Map uppercase characters to lowercase characters
if applicable.

U8_TEXTPREP_NFD

Apply Unicode Normalization Form D.

U8_TEXTPREP_NFC

Apply Unicode Normalization Form C.

U8_TEXTPREP_NFKD

Apply Unicode Normalization Form KD.

U8_TEXTPREP_NFKC

Apply Unicode Normalization Form KC.

Only one case folding option is allowed. Only one
Unicode Normalization option is allowed.

When a case folding option and a Unicode
Normalization option are specified together, UTF-8
text preparation is done by doing case folding first
and then Unicode Normalization.

If no option is specified, no processing occurs
except the simple copying of bytes from input to
output.

unicode_version
The version of Unicode data that should be used
during UTF-8 text preparation. The following values
are supported:

U8_UNICODE_320

Use Unicode 3.2.0 data during comparison.

U8_UNICODE_500

Use Unicode 5.0.0 data during comparison.

U8_UNICODE_LATEST

Use the latest Unicode version data available
which is Unicode 5.0.0 currently.

errnum
The error value when preparation is not completed or
fails. The following values are supported:

E2BIG
Text preparation stopped due to lack of
space in the output array.

EBADF
Specified option values are conflicting and
cannot be supported.

EILSEQ
Text preparation stopped due to an input
byte that does not belong to UTF-8.

EINVAL
Text preparation stopped due to an
incomplete UTF-8 character at the end of
the input array.

ERANGE
The specified Unicode version value is not
a supported version.

DESCRIPTION

The u8_textprep_str() function prepares the sequence of UTF-8 characters
in the array specified by inarray into a sequence of corresponding UTF-8
characters prepared in the array specified by outarray. The inarray
argument points to a character byte array to the first character in the
input array and inlen indicates the number of bytes to the end of the
array to be converted. The outarray argument points to a character byte
array to the first available byte in the output array and outlen
indicates the number of the available bytes to the end of the array.
Unless flag is U8_TEXTPREP_IGNORE_NULL, u8_textprep_str() normally stops
when it encounters a null byte from the input array regardless of the
current inlen value.

If flag is U8_TEXTPREP_IGNORE_INVALID and a sequence of input bytes does
not form a valid UTF-8 character, preparation stops after the previous
successfully prepared character. If flag is U8_TEXTPREP_IGNORE_INVALID
and the input array ends with an incomplete UTF-8 character, preparation
stops after the previous successfully prepared bytes. If the output array
is not large enough to hold the entire prepared text, preparation stops
just prior to the input bytes that would cause the output array to
overflow. The value pointed to by inlen is decremented to reflect the
number of bytes still not prepared in the input array. The value pointed
to by outlen is decremented to reflect the number of bytes still
available in the output array.

RETURN VALUES

The u8_textprep_str() function updates the values pointed to by inlen and
outlen arguments to reflect the extent of the preparation. When
U8_TEXTPREP_IGNORE_INVALID is specified, u8_textprep_str() returns the
number of illegal or incomplete characters found during the text
preparation. When U8_TEXTPREP_IGNORE_INVALID is not specified and the
text preparation is entirely successful, the function returns 0. If the
entire string in the input array is prepared, the value pointed to by
inlen will be 0. If the text preparation is stopped due to any conditions
mentioned above, the value pointed to by inlen will be non-zero and
errnum is set to indicate the error. If such and any other error occurs,
u8_textprep_str() returns (size_t)-1 and sets errnum to indicate the
error.

EXAMPLES

Example 1: Simple UTF-8 text preparation

#include <sys/u8_textprep.h>
.
.
.
size_t ret;
char ib[MAXPATHLEN];
char ob[MAXPATHLEN];
size_t il, ol;
int err;
.
.
.
/*
* We got a UTF-8 pathname from somewhere.
*
* Calculate the length of input string including the terminating
* NULL byte and prepare other arguments.
*/
(void) strlcpy(ib, pathname, MAXPATHLEN);
il = strlen(ib) + 1;
ol = MAXPATHLEN;

/*
* Do toupper case folding, apply Unicode Normalization Form D,
* ignore NULL byte, and ignore any illegal/incomplete characters.
*/
ret = u8_textprep_str(ib, &il, ob, &ol,
(U8_TEXTPREP_IGNORE_NULL|U8_TEXTPREP_IGNORE_INVALID|
U8_TEXTPREP_TOUPPER|U8_TEXTPREP_NFD), U8_UNICODE_LATEST, &err);
if (ret == (size_t)-1) {
if (err == E2BIG)
return (-1);
if (err == EBADF)
return (-2);
if (err == ERANGE)
return (-3);
return (-4);
}

ATTRIBUTES

NOTES

After the text preparation, the number of prepared UTF-8 characters and
the total number bytes may decrease or increase when you compare the
numbers with the input buffer.

Case conversions are performed using Unicode data of the corresponding
version. There are no locale-specific case conversions that can be
performed.

September 18, 2007 U8_TEXTPREP_STR(3C)