gio.seekable_mixin

Module for [Seekable] interface mixin

Templates 2

tmplSeekableT()

[gio.seekable.Seekable] is implemented by streams (implementations of [gio.input_stream.InputStream] or [gio.output_stream.OutputStream]) that support seeking.

Seekable streams largely fall into two categories: resizable and fixed-size.

[gio.seekable.Seekable] on fixed-sized streams is approximately the same as POSIX

lseek()) on a block device (for example: attempting to seek

past the end of the device is an error). Fixed streams typically cannot be truncated.

[gio.seekable.Seekable] on resizable streams is approximately the same as POSIX

lseek()) on a normal file. Seeking past the end and writing

data will usually cause the stream to resize by introducing zero bytes.

Functions

bool canSeek()

Tests if the stream supports the #GSeekableIface.

Returns

true if seekable can be seeked. false otherwise.

bool canTruncate()

Tests if the length of the stream can be adjusted with [gio.seekable.Seekable.truncate].

Returns

true if the stream can be truncated, false otherwise.

bool seek(long offset, glib.types.SeekType type, gio.cancellable.Cancellable cancellable = null)

Seeks in the stream by the given offset, modified by type.

Attempting to seek past the end of the stream will have different results depending on if the stream is fixed-sized or resizable. If the stream is resizable then seeking past the end and then writing will result in zeros filling the empty space. Seeking past the end of a resizable stream and reading will result in EOF. Seeking past the end of a fixed-sized stream will fail.

Any operation that would result in a negative offset will fail.

Parameters

`offset`	a #goffset.
`type`	a #GSeekType.
`cancellable`	optional #GCancellable object, null to ignore.

Returns

true if successful. If an error

has occurred, this function will return false and set error appropriately if present.

Throws

[ErrorWrap]

long tell()

Tells the current position within the stream.

Returns

the (positive or zero) offset from the beginning of the

buffer, zero if the target is not seekable.

bool truncate(long offset, gio.cancellable.Cancellable cancellable = null)

Sets the length of the stream to offset. If the stream was previously larger than offset, the extra data is discarded. If the stream was previously shorter than offset, it is extended with NUL ('\0') bytes.

If cancellable is not null, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error [gio.types.IOErrorEnum.Cancelled] will be returned. If an operation was partially finished when the operation was cancelled the partial result will be returned, without an error.

Parameters

`offset`	new length for seekable, in bytes.
`cancellable`	optional #GCancellable object, null to ignore.

Returns

true if successful. If an error

has occurred, this function will return false and set error appropriately if present.

Throws

[ErrorWrap]

tmplSeekableGidBuilderT()