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GBufferedInputStream

GBufferedInputStream — Buffered Input Stream

Properties

guint buffer-size Read / Write / Construct

Types and Values

Object Hierarchy

    GObject
    ╰── GInputStream
        ╰── GFilterInputStream
            ╰── GBufferedInputStream
                ╰── GDataInputStream

Implemented Interfaces

GBufferedInputStream implements GSeekable.

Includes

#include <gio/gio.h>

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.

Functions

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).

Parameters

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 .

Parameters

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.

Parameters

stream

a 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.

Parameters

stream

a 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.

Parameters

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.

Parameters

stream

a GBufferedInputStream

 

count

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

[out]

Returns

read-only buffer.

[array length=count][element-type guint8][transfer none]


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.

Parameters

stream

a GBufferedInputStream

 

buffer

a pointer to an allocated chunk of memory.

[array length=count][element-type guint8]

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().

Parameters

stream

a GBufferedInputStream

 

count

the number of bytes that will be read from the stream

 

cancellable

optional GCancellable object, NULL to ignore.

[nullable]

error

location to store the error occurring, 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.

Parameters

stream

a 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.

[nullable]

callback

a GAsyncReadyCallback.

[scope async]

user_data

a gpointer.

[closure]

g_buffered_input_stream_fill_finish ()

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

Finishes an asynchronous read.

Parameters

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.

Parameters

stream

a GBufferedInputStream

 

cancellable

optional GCancellable object, NULL to ignore.

[nullable]

error

location to store the error occurring, or NULL to ignore

 

Returns

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

Types and Values

GBufferedInputStream

typedef struct _GBufferedInputStream GBufferedInputStream;

Implements GFilterInputStream with a sized input buffer.

Property Details

The “buffer-size” property

  “buffer-size”              guint

The size of the backend buffer.

Flags: Read / Write / Construct

Allowed values: >= 1

Default value: 4096

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