glib-2.0/gio/gseekable.h

0001 /* GIO - GLib Input, Output and Streaming Library
0002  *
0003  * Copyright (C) 2006-2007 Red Hat, Inc.
0004  *
0005  * SPDX-License-Identifier: LGPL-2.1-or-later
0006  *
0007  * This library is free software; you can redistribute it and/or
0008  * modify it under the terms of the GNU Lesser General Public
0009  * License as published by the Free Software Foundation; either
0010  * version 2.1 of the License, or (at your option) any later version.
0011  *
0012  * This library is distributed in the hope that it will be useful,
0013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
0014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
0015  * Lesser General Public License for more details.
0016  *
0017  * You should have received a copy of the GNU Lesser General
0018  * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
0019  *
0020  * Author: Alexander Larsson <alexl@redhat.com>
0021  */
0022
0023 #ifndef __G_SEEKABLE_H__
0024 #define __G_SEEKABLE_H__
0025
0026 #if !defined (__GIO_GIO_H_INSIDE__) && !defined (GIO_COMPILATION)
0027 #error "Only <gio/gio.h> can be included directly."
0028 #endif
0029
0030 #include <gio/giotypes.h>
0031
0032 G_BEGIN_DECLS
0033
0034 #define G_TYPE_SEEKABLE            (g_seekable_get_type ())
0035 #define G_SEEKABLE(obj)            (G_TYPE_CHECK_INSTANCE_CAST ((obj), G_TYPE_SEEKABLE, GSeekable))
0036 #define G_IS_SEEKABLE(obj)         (G_TYPE_CHECK_INSTANCE_TYPE ((obj), G_TYPE_SEEKABLE))
0037 #define G_SEEKABLE_GET_IFACE(obj)  (G_TYPE_INSTANCE_GET_INTERFACE ((obj), G_TYPE_SEEKABLE, GSeekableIface))
0038
0039 typedef struct _GSeekableIface   GSeekableIface;
0040
0041 /**
0042  * GSeekableIface:
0043  * @g_iface: The parent interface.
0044  * @tell: Tells the current location within a stream.
0045  * @can_seek: Checks if seeking is supported by the stream.
0046  * @seek: Seeks to a location within a stream.
0047  * @can_truncate: Checks if truncation is supported by the stream.
0048  * @truncate_fn: Truncates a stream.
0049  *
0050  * Provides an interface for implementing seekable functionality on I/O Streams.
0051  **/
0052 struct _GSeekableIface
0053 {
0054   GTypeInterface g_iface;
0055
0056   /* Virtual Table */
0057
0058   goffset     (* tell)           (GSeekable    *seekable);
0059
0060   gboolean    (* can_seek)       (GSeekable    *seekable);
0061   gboolean    (* seek)           (GSeekable    *seekable,
0062                   goffset       offset,
0063                   GSeekType     type,
0064                   GCancellable *cancellable,
0065                   GError      **error);
0066
0067   gboolean    (* can_truncate)   (GSeekable    *seekable);
0068   gboolean    (* truncate_fn)    (GSeekable    *seekable,
0069                   goffset       offset,
0070                   GCancellable *cancellable,
0071                   GError       **error);
0072
0073   /* TODO: Async seek/truncate */
0074 };
0075
0076 GIO_AVAILABLE_IN_ALL
0077 GType    g_seekable_get_type     (void) G_GNUC_CONST;
0078
0079 GIO_AVAILABLE_IN_ALL
0080 goffset  g_seekable_tell         (GSeekable     *seekable);
0081 GIO_AVAILABLE_IN_ALL
0082 gboolean g_seekable_can_seek     (GSeekable     *seekable);
0083 GIO_AVAILABLE_IN_ALL
0084 gboolean g_seekable_seek         (GSeekable     *seekable,
0085                   goffset        offset,
0086                   GSeekType      type,
0087                   GCancellable  *cancellable,
0088                   GError       **error);
0089 GIO_AVAILABLE_IN_ALL
0090 gboolean g_seekable_can_truncate (GSeekable     *seekable);
0091 GIO_AVAILABLE_IN_ALL
0092 gboolean g_seekable_truncate     (GSeekable     *seekable,
0093                   goffset        offset,
0094                   GCancellable  *cancellable,
0095                   GError       **error);
0096
0097 G_END_DECLS
0098
0099
0100 #endif /* __G_SEEKABLE_H__ */