Tribblix: manual page: kiconv.9f

KICONV(9F) Kernel Functions for Drivers KICONV(9F)

NAME

kiconv - buffer-based code conversion function

SYNOPSIS

#include <sys/types.h>
#include <sys/errno.h>
#include <sys/sunddi.h>

size_t kiconv(kiconv_t cd, char **inbuf, size_t *inbytesleft,
char **outbuf, size_t *outbytesleft, int *errno);

INTERFACE LEVEL

illumos DDI specific (illumos DDI).

PARAMETERS

The parameters for the kiconv function are as follows:

cd
Code conversion descriptor indicating the code
conversion and conversion state.

inbuf
Points to an address of a buffer containing a
sequence of character bytes in fromcode codeset to be
converted. After the conversion, the variable is
updated to point to the byte following the last byte
that was successfully used in the conversion.

inbytesleft
As an input parameter, the number of bytes to be
converted in inbuf. As an output parameter, the
number of bytes in inbuf still not converted after
the conversion.

outbuf
Points to an address of a buffer where converted
character bytes in tocode codeset can be saved. After
the conversion, the variable is updated to point to
the byte following the last byte of converted output
data.

outbytesleft
As an input parameter, the number of available bytes
at outbuf where converted character bytes can be
saved. As an output parameter, the number of bytes
still available at outbuf after the conversion.

errno
Indicates the error when conversion is not completed
or failed. The following are possible values:

EILSEQ
The input conversion was stopped due to
an input byte that does not belong to
the input codeset.

E2BIG
The input conversion was stopped due to
lack of space in the output buffer.

EINVAL
The input conversion was stopped due to
an incomplete character or shift
sequence at the end of the input buffer.

EBADF
The cd input parameter is not a valid
open code conversion descriptor.

DESCRIPTION

The kiconv() function converts the sequence of characters from one
codeset, in the array specified by inbuf, into a sequence of
corresponding characters in another codeset, in the array specified
by outbuf. The codesets are those specified in the kiconv_open() call
that returned the code conversion descriptor, cd. The inbuf parameter
points to a variable that points to the first character in the input
buffer and inbytesleft indicates the number of bytes to the end of
the buffer to be converted. The outbuf parameter points to a variable
that points to the first available byte in the output buffer and
outbytesleft indicates the number of the available bytes to the end
of the buffer.

For state-dependent encodings, the conversion descriptor cd is placed
into its initial shift state by a call for which inbuf is a null
pointer, or for which inbuf points to a null pointer. When kiconv()
is called in this way, and if outbuf is not a null pointer or a
pointer to a null pointer, and outbytesleft points to a positive
value, kiconv() places, if any, into the output buffer, the byte
sequence to change the output buffer to its initial shift state. If
the output buffer is not large enough to hold the entire reset
sequence, kiconv() fails and sets errno to E2BIG. Subsequent calls
with inbuf as other than a null pointer or a pointer to a null
pointer cause the conversion to take place from the current state of
the conversion descriptor.

If a sequence of input bytes does not form a valid character in the
specified codeset, conversion stops after the previous successfully
converted character. If the input buffer ends with an incomplete
character or shift sequence, conversion stops after the previous
successfully converted bytes. If the output buffer is not large
enough to hold the entire converted input, conversion stops just
prior to the input bytes that would cause the output buffer to
overflow. The variable pointed to by inbuf is updated to point to the
byte following the last byte that was successfully used in the
conversion. The value pointed to by inbytesleft is decremented to
reflect the number of bytes still not converted in the input buffer.
The variable pointed to by outbuf is updated to point to the byte
following the last byte of converted output data. The value pointed
to by outbytesleft is decremented to reflect the number of bytes
still available in the output buffer. For state-dependent encodings,
the conversion descriptor is updated to reflect the shift state in
effect at the end of the last successfully converted byte sequence.

If kiconv() encounters a character in the input buffer that is legal,
but for which an identical character does not exist in the target
codeset, kiconv() performs an implementation-defined conversion (that
is, a non-identical conversion) on this character.

RETURN VALUES

The kiconv() function updates the variables pointed to by the
parameters to reflect the extent of the conversion and returns the
number of non-identical conversions performed. If the entire string
in the input buffer is converted, the value pointed to by inbytesleft
is 0. If the input conversion is stopped due to any conditions
mentioned above, the value pointed to by inbytesleft is non-zero and
errno is set to indicate the condition. If such and other error
occurs, kiconv() returns (size_t)-1 and sets errno to indicate the
error.

CONTEXT

kiconv() can be called from user or interrupt context.

EXAMPLES

Example 1: Performing a Simple Conversion

The following example shows how to perform a simple conversion using
kiconv() with a limited size of output buffer:

#include <sys/types.h>
#include <sys/errno.h>
#include <sys/sunddi.h>

int
doconversion(char *fromcode, char *tocode, char *inbuf, char *outbuf,
size_t inlen, size_t *outlen)
{
kiconv_t cd;
size_t ileft, ret;
int err;

cd = kiconv_open((const char *)tocode, (const char *)fromcode);
if (cd == (kiconv_t)-1) {
/* Cannot open conversion. */
return (-1);
}

ret = kiconv(cd, &inbuf, &inlen, &outbuf, outlen, &err);
if (ret == (size_t)-1)
goto doconv_error_return;

/*
* Reset the conversion descriptor. This will also
* make sure to write to output buffer any saved bytes
* in the conversion descriptor state.
*/
ileft = 0;
ret = kiconv(cd, (char *)NULL, &ileft, &outbuf, outlen, &err);
if (ret == (size_t)-1)
goto doconv_error_return;

(void) kiconv_close(cd);

return (0);

doconv_error_return:
(void) kiconv_close(cd);

/* Need more output buffer. */
if (err == E2BIG)
return (-2);

/* Illegal sequence? */
if (err == EILSEQ)
return (-3);

/* Incomplete character? */
if (err == EINVAL)
return (-4);

/*
* Bad code conversion descriptor or any other unknown error.
*/
return (-5);
}

ATTRIBUTES

NOTES

The iconv(3C) man page also has a good example code that can be
referenced.

October 16, 2007 KICONV(9F)