This is the main operation used when converting data. It is to be called
multiple times in a loop, and each time it will do some work, i.e.
producing some output (in outbuf) or consuming some input (from inbuf) or
both. If its not possible to do any work an error is returned.
Note that a single call may not consume all input (or any input at all).
Also a call may produce output even if given no input, due to state stored
in the converter producing output.
If any data was either produced or consumed, and then an error happens, then
only the successful conversion is reported and the error is returned on the
next call.
A full conversion loop involves calling this method repeatedly, each time
giving it new input and space output space. When there is no more input
data after the data in inbuf, the flag G_CONVERTER_INPUT_AT_END must be set.
The loop will be (unless some error happens) returning G_CONVERTER_CONVERTED
each time until all data is consumed and all output is produced, then
G_CONVERTER_FINISHED is returned instead. Note, that G_CONVERTER_FINISHED
may be returned even if G_CONVERTER_INPUT_AT_END is not set, for instance
in a decompression converter where the end of data is detectable from the
data (and there might even be other data after the end of the compressed data).
When some data has successfully been converted bytes_read and is set to
the number of bytes read from inbuf, and bytes_written is set to indicate
how many bytes was written to outbuf. If there are more data to output
or consume (i.e. unless the G_CONVERTER_INPUT_AT_END is specified) then
G_CONVERTER_CONVERTED is returned, and if no more data is to be output
then G_CONVERTER_FINISHED is returned.
On error G_CONVERTER_ERROR is returned and error is set accordingly.
Some errors need special handling:
G_IO_ERROR_NO_SPACE is returned if there is not enough space
to write the resulting converted data, the application should
call the function again with a larger outbuf to continue.
G_IO_ERROR_PARTIAL_INPUT is returned if there is not enough
input to fully determine what the conversion should produce,
and the G_CONVERTER_INPUT_AT_END flag is not set. This happens for
example with an incomplete multibyte sequence when converting text,
or when a regexp matches up to the end of the input (and may match
further input). It may also happen when inbuf_size is zero and
there is no more data to produce.
When this happens the application should read more input and then
call the function again. If further input shows that there is no
more data call the function again with the same data but with
the G_CONVERTER_INPUT_AT_END flag set. This may cause the conversion
to finish as e.g. in the regexp match case (or, to fail again with
G_IO_ERROR_PARTIAL_INPUT in e.g. a charset conversion where the
input is actually partial).
After g_converter_convert() has returned G_CONVERTER_FINISHED the
converter object is in an invalid state where its not allowed
to call g_converter_convert() anymore. At this time you can only
free the object or call g_converter_reset() to reset it to the
initial state.
If the flag G_CONVERTER_FLUSH is set then conversion is modified
to try to write out all internal state to the output. The application
has to call the function multiple times with the flag set, and when
the availible input has been consumed and all internal state has
been produced then G_CONVERTER_FLUSHED (or G_CONVERTER_FINISHED if
really at the end) is returned instead of G_CONVERTER_CONVERTED.
This is somewhat similar to what happens at the end of the input stream,
but done in the middle of the data.
This has different meanings for different conversions. For instance
in a compression converter it would mean that we flush all the
compression state into output such that if you uncompress the
compressed data you get back all the input data. Doing this may
make the final file larger due to padding though. Another example
is a regexp conversion, where if you at the end of the flushed data
have a match, but there is also a potential longer match. In the
non-flushed case we would ask for more input, but when flushing we
treat this as the end of input and do the match.
Flushing is not always possible (like if a charset converter flushes
at a partial multibyte sequence). Converters are supposed to try
to produce as much output as possible and then return an error
(typically G_IO_ERROR_PARTIAL_INPUT).

Parameters:

String inbuf Required (not null)

the buffer containing the data to convert.

guint32 inbuf_size Required (not null)

the number of bytes in inbuf

void* outbuf Required (not null)

a buffer to write converted data in.

guint32 outbuf_size Required (not null)

the number of bytes in outbuf, must be at least one

Gio.ConverterFlags flags Required (not null)

a GConvertFlags controlling the conversion details

Object out_values

guint32 bytes_read

guint32 bytes_written

Returns:

Gio.ConverterResult a GConverterResult, G_CONVERTER_ERROR on error.

Initializes the object implementing the interface. This must be
done before any real use of the object after initial construction.
Implementations may also support cancellation. If cancellable is not NULL,
then initialization can be cancelled by triggering the cancellable object
from another thread. If the operation was cancelled, the error
G_IO_ERROR_CANCELLED will be returned. If cancellable is not NULL and
the object doesn't support cancellable initialization the error
G_IO_ERROR_NOT_SUPPORTED will be returned.
If this function is not called, or returns with an error then all
operations on the object should fail, generally returning the
error G_IO_ERROR_NOT_INITIALIZED.
Implementations of this method must be idempotent, i.e. multiple calls
to this function with the same argument should return the same results.
Only the first call initializes the object, further calls return the result
of the first call. This is so that its safe to implement the singleton
pattern in the GObject constructor function.
return FALSE and set error appropriately if present.

Parameters:

Gio.Cancellable cancellable

optional GCancellable object, NULL to ignore.

Returns:

gboolean TRUE if successful. If an error has occurred, this function will

Resets all internal state in the converter, making it behave
as if it was just created. If the converter has any internal
state that would produce output then that output is lost.

Returns:

none