GDataInputStream
3
GIO Library

# GDataInputStream

Data Input Stream

## Synopsis

    #include <gio/gio.h>

                        GDataInputStream;
    enum                GDataStreamByteOrder;
    enum                GDataStreamNewlineType;
    GDataInputStream *  g_data_input_stream_new             (GInputStream *base_stream);
    void                g_data_input_stream_set_byte_order  (GDataInputStream *stream,
                                                             GDataStreamByteOrder order);
    GDataStreamByteOrder  g_data_input_stream_get_byte_order
                                                            (GDataInputStream *stream);
    void                g_data_input_stream_set_newline_type
                                                            (GDataInputStream *stream,
                                                             GDataStreamNewlineType type);
    GDataStreamNewlineType  g_data_input_stream_get_newline_type
                                                            (GDataInputStream *stream);
    guchar              g_data_input_stream_read_byte       (GDataInputStream *stream,
                                                             GCancellable *cancellable,
                                                             GError **error);
    gint16              g_data_input_stream_read_int16      (GDataInputStream *stream,
                                                             GCancellable *cancellable,
                                                             GError **error);
    guint16             g_data_input_stream_read_uint16     (GDataInputStream *stream,
                                                             GCancellable *cancellable,
                                                             GError **error);
    gint32              g_data_input_stream_read_int32      (GDataInputStream *stream,
                                                             GCancellable *cancellable,
                                                             GError **error);
    guint32             g_data_input_stream_read_uint32     (GDataInputStream *stream,
                                                             GCancellable *cancellable,
                                                             GError **error);
    gint64              g_data_input_stream_read_int64      (GDataInputStream *stream,
                                                             GCancellable *cancellable,
                                                             GError **error);
    guint64             g_data_input_stream_read_uint64     (GDataInputStream *stream,
                                                             GCancellable *cancellable,
                                                             GError **error);
    char *              g_data_input_stream_read_line       (GDataInputStream *stream,
                                                             gsize *length,
                                                             GCancellable *cancellable,
                                                             GError **error);
    void                g_data_input_stream_read_line_async (GDataInputStream *stream,
                                                             gint io_priority,
                                                             GCancellable *cancellable,
                                                             GAsyncReadyCallback callback,
                                                             gpointer user_data);
    char *              g_data_input_stream_read_line_finish
                                                            (GDataInputStream *stream,
                                                             GAsyncResult *result,
                                                             gsize *length,
                                                             GError **error);
    char *              g_data_input_stream_read_until      (GDataInputStream *stream,
                                                             const gchar *stop_chars,
                                                             gsize *length,
                                                             GCancellable *cancellable,
                                                             GError **error);
    void                g_data_input_stream_read_until_async
                                                            (GDataInputStream *stream,
                                                             const gchar *stop_chars,
                                                             gint io_priority,
                                                             GCancellable *cancellable,
                                                             GAsyncReadyCallback callback,
                                                             gpointer user_data);
    char *              g_data_input_stream_read_until_finish
                                                            (GDataInputStream *stream,
                                                             GAsyncResult *result,
                                                             gsize *length,
                                                             GError **error);

## Object Hierarchy

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

## Properties

      "byte-order"               GDataStreamByteOrder  : Read / Write
      "newline-type"             GDataStreamNewlineType  : Read / Write

## Description

Data input stream implements GInputStream and includes functions for reading structured data directly from a binary input stream.

## Details

### GDataInputStream

    typedef struct _GDataInputStream GDataInputStream;

An implementation of GBufferedInputStream that allows for high-level data manipulation of arbitrary data (including binary operations).

### enum GDataStreamByteOrder

    typedef enum {
      G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN,
      G_DATA_STREAM_BYTE_ORDER_LITTLE_ENDIAN,
      G_DATA_STREAM_BYTE_ORDER_HOST_ENDIAN
    } GDataStreamByteOrder;

GDataStreamByteOrder is used to ensure proper endianness of streaming data sources across various machine architectures.

`G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN`

  Selects Big Endian byte order.

`G_DATA_STREAM_BYTE_ORDER_LITTLE_ENDIAN`

  Selects Little Endian byte order.

`G_DATA_STREAM_BYTE_ORDER_HOST_ENDIAN`

  Selects endianness based on host machine's architecture.

### enum GDataStreamNewlineType

    typedef enum {
      G_DATA_STREAM_NEWLINE_TYPE_LF,
      G_DATA_STREAM_NEWLINE_TYPE_CR,
      G_DATA_STREAM_NEWLINE_TYPE_CR_LF,
      G_DATA_STREAM_NEWLINE_TYPE_ANY
    } GDataStreamNewlineType;

GDataStreamNewlineType is used when checking for or setting the line endings for a given file.

`G_DATA_STREAM_NEWLINE_TYPE_LF`

  Selects "LF" line endings, common on most modern UNIX platforms.

`G_DATA_STREAM_NEWLINE_TYPE_CR`

  Selects "CR" line endings.

`G_DATA_STREAM_NEWLINE_TYPE_CR_LF`

  Selects "CR, LF" line ending, common on Microsoft Windows.

`G_DATA_STREAM_NEWLINE_TYPE_ANY`

  Automatically try to handle any line ending type.

### g_data_input_stream_new ()

    GDataInputStream *  g_data_input_stream_new             (GInputStream *base_stream);

Creates a new data input stream for the `base_stream`.

`base_stream` :

  a GInputStream.

Returns :

  a new GDataInputStream.

### g_data_input_stream_set_byte_order ()

    void                g_data_input_stream_set_byte_order  (GDataInputStream *stream,
                                                             GDataStreamByteOrder order);

This function sets the byte order for the given `stream`. All subsequent reads from the `stream` will be read in the given `order`.

`stream` :

  a given GDataInputStream.

`order` :

  a GDataStreamByteOrder to set.

### g_data_input_stream_get_byte_order ()

    GDataStreamByteOrder  g_data_input_stream_get_byte_order
                                                            (GDataInputStream *stream);

Gets the byte order for the data input stream.

`stream` :

  a given GDataInputStream.

Returns :

  the `stream`'s current GDataStreamByteOrder.

### g_data_input_stream_set_newline_type ()

    void                g_data_input_stream_set_newline_type
                                                            (GDataInputStream *stream,
                                                             GDataStreamNewlineType type);

Sets the newline type for the `stream`.

Note that using G_DATA_STREAM_NEWLINE_TYPE_ANY is slightly unsafe. If a read chunk ends in "CR" we must read an additional byte to know if this is "CR" or "CR LF", and this might block if there is no more data availible.

`stream` :

  a GDataInputStream.

`type` :

  the type of new line return as GDataStreamNewlineType.

### g_data_input_stream_get_newline_type ()

    GDataStreamNewlineType  g_data_input_stream_get_newline_type
                                                            (GDataInputStream *stream);

Gets the current newline type for the `stream`.

`stream` :

  a given GDataInputStream.

Returns :

  GDataStreamNewlineType for the given `stream`.

### g_data_input_stream_read_byte ()

    guchar              g_data_input_stream_read_byte       (GDataInputStream *stream,
                                                             GCancellable *cancellable,
                                                             GError **error);

Reads an unsigned 8-bit/1-byte value from `stream`.

`stream` :

  a given GDataInputStream.

`cancellable` :

  optional GCancellable object, `NULL` to ignore.

`error` :

  GError for error reporting.

Returns :

  an unsigned 8-bit/1-byte value read from the `stream` or `0` if an error occurred.

### g_data_input_stream_read_int16 ()

    gint16              g_data_input_stream_read_int16      (GDataInputStream *stream,
                                                             GCancellable *cancellable,
                                                             GError **error);

Reads a 16-bit/2-byte value from `stream`.

In order to get the correct byte order for this read operation, see `g_data_stream_get_byte_order()` and `g_data_stream_set_byte_order()`.

`stream` :

  a given GDataInputStream.

`cancellable` :

  optional GCancellable object, `NULL` to ignore.

`error` :

  GError for error reporting.

Returns :

  a signed 16-bit/2-byte value read from `stream` or `0` if an error occurred.

### g_data_input_stream_read_uint16 ()

    guint16             g_data_input_stream_read_uint16     (GDataInputStream *stream,
                                                             GCancellable *cancellable,
                                                             GError **error);

Reads an unsigned 16-bit/2-byte value from `stream`.

In order to get the correct byte order for this read operation, see `g_data_stream_get_byte_order()` and `g_data_stream_set_byte_order()`.

`stream` :

  a given GDataInputStream.

`cancellable` :

  optional GCancellable object, `NULL` to ignore.

`error` :

  GError for error reporting.

Returns :

  an unsigned 16-bit/2-byte value read from the `stream` or `0` if an error occurred.

### g_data_input_stream_read_int32 ()

    gint32              g_data_input_stream_read_int32      (GDataInputStream *stream,
                                                             GCancellable *cancellable,
                                                             GError **error);

Reads a signed 32-bit/4-byte value from `stream`.

In order to get the correct byte order for this read operation, see `g_data_stream_get_byte_order()` and `g_data_stream_set_byte_order()`.

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.

`stream` :

  a given GDataInputStream.

`cancellable` :

  optional GCancellable object, `NULL` to ignore.

`error` :

  GError for error reporting.

Returns :

  a signed 32-bit/4-byte value read from the `stream` or `0` if an error occurred.

### g_data_input_stream_read_uint32 ()

    guint32             g_data_input_stream_read_uint32     (GDataInputStream *stream,
                                                             GCancellable *cancellable,
                                                             GError **error);

Reads an unsigned 32-bit/4-byte value from `stream`.

In order to get the correct byte order for this read operation, see `g_data_stream_get_byte_order()` and `g_data_stream_set_byte_order()`.

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.

`stream` :

  a given GDataInputStream.

`cancellable` :

  optional GCancellable object, `NULL` to ignore.

`error` :

  GError for error reporting.

Returns :

  an unsigned 32-bit/4-byte value read from the `stream` or `0` if an error occurred.

### g_data_input_stream_read_int64 ()

    gint64              g_data_input_stream_read_int64      (GDataInputStream *stream,
                                                             GCancellable *cancellable,
                                                             GError **error);

Reads a 64-bit/8-byte value from `stream`.

In order to get the correct byte order for this read operation, see `g_data_stream_get_byte_order()` and `g_data_stream_set_byte_order()`.

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.

`stream` :

  a given GDataInputStream.

`cancellable` :

  optional GCancellable object, `NULL` to ignore.

`error` :

  GError for error reporting.

Returns :

  a signed 64-bit/8-byte value read from `stream` or `0` if an error occurred.

### g_data_input_stream_read_uint64 ()

    guint64             g_data_input_stream_read_uint64     (GDataInputStream *stream,
                                                             GCancellable *cancellable,
                                                             GError **error);

Reads an unsigned 64-bit/8-byte value from `stream`.

In order to get the correct byte order for this read operation, see `g_data_stream_get_byte_order()`.

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.

`stream` :

  a given GDataInputStream.

`cancellable` :

  optional GCancellable object, `NULL` to ignore.

`error` :

  GError for error reporting.

Returns :

  an unsigned 64-bit/8-byte read from `stream` or `0` if an error occurred.

### g_data_input_stream_read_line ()

    char *              g_data_input_stream_read_line       (GDataInputStream *stream,
                                                             gsize *length,
                                                             GCancellable *cancellable,
                                                             GError **error);

Reads a line from the data input stream.

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.

`stream` :

  a given GDataInputStream.

`length` :

  a gsize to get the length of the data read in.

`cancellable` :

  optional GCancellable object, `NULL` to ignore.

`error` :

  GError for error reporting.

Returns :

  a string with the line that was read in (without the newlines). Set `length` to a gsize to get the length of the read line. On an error, it will return `NULL` and `error` will be set. If there's no content to read, it will still return `NULL`, but `error` won't be set.

### g_data_input_stream_read_line_async ()

    void                g_data_input_stream_read_line_async (GDataInputStream *stream,
                                                             gint io_priority,
                                                             GCancellable *cancellable,
                                                             GAsyncReadyCallback callback,
                                                             gpointer user_data);

The asynchronous version of `g_data_input_stream_read_line()`. It is an error to have two outstanding calls to this function.

When the operation is finished, `callback` will be called. You can then call `g_data_input_stream_read_line_finish()` to get the result of the operation.

`stream` :

  a given GDataInputStream.

`io_priority` :

  the I/O priority of the request.

`cancellable` :

  optional GCancellable object, `NULL` to ignore.

`callback` :

  callback to call when the request is satisfied.

`user_data` :

  the data to pass to callback function.

Since 2.20

### g_data_input_stream_read_line_finish ()

    char *              g_data_input_stream_read_line_finish
                                                            (GDataInputStream *stream,
                                                             GAsyncResult *result,
                                                             gsize *length,
                                                             GError **error);

Finish an asynchronous call started by `g_data_input_stream_read_line_async()`.

`stream` :

  a given GDataInputStream.

`result` :

  the GAsyncResult that was provided to the callback.

`length` :

  a gsize to get the length of the data read in.

`error` :

  GError for error reporting.

Returns :

  a string with the line that was read in (without the newlines). Set `length` to a gsize to get the length of the read line. On an error, it will return `NULL` and `error` will be set. If there's no content to read, it will still return `NULL`, but `error` won't be set.

Since 2,20

### g_data_input_stream_read_until ()

    char *              g_data_input_stream_read_until      (GDataInputStream *stream,
                                                             const gchar *stop_chars,
                                                             gsize *length,
                                                             GCancellable *cancellable,
                                                             GError **error);

Reads a string from the data input stream, up to the first occurrence of any of the stop characters.

`stream` :

  a given GDataInputStream.

`stop_chars` :

  characters to terminate the read.

`length` :

  a gsize to get the length of the data read in.

`cancellable` :

  optional GCancellable object, `NULL` to ignore.

`error` :

  GError for error reporting.

Returns :

  a string with the data that was read before encountering any of the stop characters. Set `length` to a gsize to get the length of the string. This function will return `NULL` on an error.

### g_data_input_stream_read_until_async ()

    void                g_data_input_stream_read_until_async
                                                            (GDataInputStream *stream,
                                                             const gchar *stop_chars,
                                                             gint io_priority,
                                                             GCancellable *cancellable,
                                                             GAsyncReadyCallback callback,
                                                             gpointer user_data);

The asynchronous version of `g_data_input_stream_read_until()`. It is an error to have two outstanding calls to this function.

When the operation is finished, `callback` will be called. You can then call `g_data_input_stream_read_until_finish()` to get the result of the operation.

`stream` :

  a given GDataInputStream.

`stop_chars` :

  characters to terminate the read.

`io_priority` :

  the I/O priority of the request.

`cancellable` :

  optional GCancellable object, `NULL` to ignore.

`callback` :

  callback to call when the request is satisfied.

`user_data` :

  the data to pass to callback function.

Since 2.20

### g_data_input_stream_read_until_finish ()

    char *              g_data_input_stream_read_until_finish
                                                            (GDataInputStream *stream,
                                                             GAsyncResult *result,
                                                             gsize *length,
                                                             GError **error);

Finish an asynchronous call started by `g_data_input_stream_read_until_async()`.

`stream` :

  a given GDataInputStream.

`result` :

  the GAsyncResult that was provided to the callback.

`length` :

  a gsize to get the length of the data read in.

`error` :

  GError for error reporting.

Returns :

  a string with the data that was read before encountering any of the stop characters. Set `length` to a gsize to get the length of the string. This function will return `NULL` on an error.

Since 2.20

## Property Details

### The `"byte-order"` property

      "byte-order"               GDataStreamByteOrder  : Read / Write

The byte order.

Default value: G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN

### The `"newline-type"` property

      "newline-type"             GDataStreamNewlineType  : Read / Write

The accepted types of line ending.

Default value: G_DATA_STREAM_NEWLINE_TYPE_LF

## See Also

#GInputStream