GBufferedInputStream

GBufferedInputStream — Buffered Input Stream

Synopsis


#include <gio/gio.h>

                    GBufferedInputStream;
GInputStream*       g_buffered_input_stream_new         (GInputStream *base_stream);
GInputStream*       g_buffered_input_stream_new_sized   (GInputStream *base_stream,
                                                         gsize size);
gsize               g_buffered_input_stream_get_buffer_size
                                                        (GBufferedInputStream *stream);
void                g_buffered_input_stream_set_buffer_size
                                                        (GBufferedInputStream *stream,
                                                         gsize size);
gsize               g_buffered_input_stream_get_available
                                                        (GBufferedInputStream *stream);
const void*         g_buffered_input_stream_peek_buffer (GBufferedInputStream *stream,
                                                         gsize *count);
gsize               g_buffered_input_stream_peek        (GBufferedInputStream *stream,
                                                         void *buffer,
                                                         gsize offset,
                                                         gsize count);
gssize              g_buffered_input_stream_fill        (GBufferedInputStream *stream,
                                                         gssize count,
                                                         GCancellable *cancellable,
                                                         GError **error);
void                g_buffered_input_stream_fill_async  (GBufferedInputStream *stream,
                                                         gssize count,
                                                         int io_priority,
                                                         GCancellable *cancellable,
                                                         GAsyncReadyCallback callback,
                                                         gpointer user_data);
gssize              g_buffered_input_stream_fill_finish (GBufferedInputStream *stream,
                                                         GAsyncResult *result,
                                                         GError **error);
int                 g_buffered_input_stream_read_byte   (GBufferedInputStream *stream,
                                                         GCancellable *cancellable,
                                                         GError **error);

Object Hierarchy

  GObject
   +----GInputStream
         +----GFilterInputStream
               +----GBufferedInputStream
                     +----GDataInputStream

Properties

  "buffer-size"              guint                 : Read / Write / Construct

Description

Buffered input stream implements GFilterInputStream and provides for buffered reads.

By default, GBufferedInputStream's buffer size is set at 4 kilobytes.

To create a buffered input stream, use g_buffered_input_stream_new(), or g_buffered_input_stream_new_sized() to specify the buffer's size at construction.

To get the size of a buffer within a buffered input stream, use g_buffered_input_stream_get_buffer_size(). To change the size of a buffered input stream's buffer, use g_buffered_input_stream_set_buffer_size(). Note that the buffer's size cannot be reduced below the size of the data within the buffer.

Details

GBufferedInputStream

typedef struct _GBufferedInputStream GBufferedInputStream;

Implements GFilterInputStream with a sized input buffer.


g_buffered_input_stream_new ()

GInputStream*       g_buffered_input_stream_new         (GInputStream *base_stream);

Creates a new GInputStream from the given base_stream, with a buffer set to the default size (4 kilobytes).

base_stream :

a GInputStream.

Returns :

a GInputStream for the given base_stream.

g_buffered_input_stream_new_sized ()

GInputStream*       g_buffered_input_stream_new_sized   (GInputStream *base_stream,
                                                         gsize size);

Creates a new GBufferedInputStream from the given base_stream, with a buffer set to size.

base_stream :

a GInputStream.

size :

a gsize.

Returns :

a GInputStream.

g_buffered_input_stream_get_buffer_size ()

gsize               g_buffered_input_stream_get_buffer_size
                                                        (GBufferedInputStream *stream);

Gets the size of the input buffer.

stream :

GBufferedInputStream.

Returns :

the current buffer size.

g_buffered_input_stream_set_buffer_size ()

void                g_buffered_input_stream_set_buffer_size
                                                        (GBufferedInputStream *stream,
                                                         gsize size);

Sets the size of the internal buffer of stream to size, or to the size of the contents of the buffer. The buffer can never be resized smaller than its current contents.

stream :

GBufferedInputStream.

size :

a gsize.

g_buffered_input_stream_get_available ()

gsize               g_buffered_input_stream_get_available
                                                        (GBufferedInputStream *stream);

Gets the size of the available data within the stream.

stream :

GBufferedInputStream.

Returns :

size of the available stream.

g_buffered_input_stream_peek_buffer ()

const void*         g_buffered_input_stream_peek_buffer (GBufferedInputStream *stream,
                                                         gsize *count);

Returns the buffer with the currently available bytes. The returned buffer must not be modified and will become invalid when reading from the stream or filling the buffer.

stream :

a GBufferedInputStream.

count :

a gsize to get the number of bytes available in the buffer.

Returns :

read-only buffer

g_buffered_input_stream_peek ()

gsize               g_buffered_input_stream_peek        (GBufferedInputStream *stream,
                                                         void *buffer,
                                                         gsize offset,
                                                         gsize count);

Peeks in the buffer, copying data of size count into buffer, offset offset bytes.

stream :

a GBufferedInputStream.

buffer :

a pointer to an allocated chunk of memory.

offset :

a gsize.

count :

a gsize.

Returns :

a gsize of the number of bytes peeked, or -1 on error.

g_buffered_input_stream_fill ()

gssize              g_buffered_input_stream_fill        (GBufferedInputStream *stream,
                                                         gssize count,
                                                         GCancellable *cancellable,
                                                         GError **error);

Tries to read count bytes from the stream into the buffer. Will block during this read.

If count is zero, returns zero and does nothing. A value of count larger than G_MAXSSIZE will cause a G_IO_ERROR_INVALID_ARGUMENT error.

On success, the number of bytes read into the buffer is returned. It is not an error if this is not the same as the requested size, as it can happen e.g. near the end of a file. Zero is returned on end of file (or if count is zero), but never otherwise.

If count is -1 then the attempted read size is equal to the number of bytes that are required to fill the buffer.

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 G_IO_ERROR_CANCELLED will be returned. If an operation was partially finished when the operation was cancelled the partial result will be returned, without an error.

On error -1 is returned and error is set accordingly.

For the asynchronous, non-blocking, version of this function, see g_buffered_input_stream_fill_async().

stream :

GBufferedInputStream.

count :

the number of bytes that will be read from the stream.

cancellable :

optional GCancellable object, NULL to ignore.

error :

location to store the error occuring, or NULL to ignore.

Returns :

the number of bytes read into stream's buffer, up to count, or -1 on error.

g_buffered_input_stream_fill_async ()

void                g_buffered_input_stream_fill_async  (GBufferedInputStream *stream,
                                                         gssize count,
                                                         int io_priority,
                                                         GCancellable *cancellable,
                                                         GAsyncReadyCallback callback,
                                                         gpointer user_data);

Reads data into stream's buffer asynchronously, up to count size. io_priority can be used to prioritize reads. For the synchronous version of this function, see g_buffered_input_stream_fill().

If count is -1 then the attempted read size is equal to the number of bytes that are required to fill the buffer.

stream :

GBufferedInputStream.

count :

the number of bytes that will be read from the stream.

io_priority :

the I/O priority of the request.

cancellable :

optional GCancellable object

callback :

a GAsyncReadyCallback.

user_data :

a gpointer.

g_buffered_input_stream_fill_finish ()

gssize              g_buffered_input_stream_fill_finish (GBufferedInputStream *stream,
                                                         GAsyncResult *result,
                                                         GError **error);

Finishes an asynchronous read.

stream :

a GBufferedInputStream.

result :

a GAsyncResult.

error :

a GError.

Returns :

a gssize of the read stream, or -1 on an error.

g_buffered_input_stream_read_byte ()

int                 g_buffered_input_stream_read_byte   (GBufferedInputStream *stream,
                                                         GCancellable *cancellable,
                                                         GError **error);

Tries to read a single byte from the stream or the buffer. Will block during this read.

On success, the byte read from the stream is returned. On end of stream -1 is returned but it's not an exceptional error and error is not set.

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 G_IO_ERROR_CANCELLED will be returned. If an operation was partially finished when the operation was cancelled the partial result will be returned, without an error.

On error -1 is returned and error is set accordingly.

stream :

GBufferedInputStream.

cancellable :

optional GCancellable object, NULL to ignore.

error :

location to store the error occuring, or NULL to ignore.

Returns :

the byte read from the stream, or -1 on end of stream or error.

Property Details

The "buffer-size" property

  "buffer-size"              guint                 : Read / Write / Construct

The size of the backend buffer.

Allowed values: >= 1

Default value: 4096

See Also

#GFilterInputStream, GInputStream