gio/gseekable.h

   1 /* GIO - GLib Input, Output and Streaming Library
   2  *
   3  * Copyright (C) 2006-2007 Red Hat, Inc.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General
  16  * Public License along with this library; if not, write to the
  17  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  18  * Boston, MA 02111-1307, USA.
  19  *
  20  * Author: Alexander Larsson <alexl@redhat.com>
  21  */
  22
  23 #if !defined (__GIO_GIO_H_INSIDE__) && !defined (GIO_COMPILATION)
  24 #error "Only <gio/gio.h> can be included directly."
  25 #endif
  26
  27 #ifndef __G_SEEKABLE_H__
  28 #define __G_SEEKABLE_H__
  29
  30 #include <gio/giotypes.h>
  31
  32 G_BEGIN_DECLS
  33
  34 #define G_TYPE_SEEKABLE            (g_seekable_get_type ())
  35 #define G_SEEKABLE(obj)            (G_TYPE_CHECK_INSTANCE_CAST ((obj), G_TYPE_SEEKABLE, GSeekable))
  36 #define G_IS_SEEKABLE(obj)         (G_TYPE_CHECK_INSTANCE_TYPE ((obj), G_TYPE_SEEKABLE))
  37 #define G_SEEKABLE_GET_IFACE(obj)  (G_TYPE_INSTANCE_GET_INTERFACE ((obj), G_TYPE_SEEKABLE, GSeekableIface))
  38
  39 /**
  40  * GSeekable:
  41  *
  42  * Seek object for streaming operations.
  43  **/
  44 typedef struct _GSeekableIface   GSeekableIface;
  45
  46 /**
  47  * GSeekableIface:
  48  * @g_iface: The parent interface.
  49  * @tell: Tells the current location within a stream.
  50  * @can_seek: Checks if seeking is supported by the stream.
  51  * @seek: Seeks to a location within a stream.
  52  * @can_truncate: Chekcs if truncation is suppored by the stream.
  53  * @truncate_fn: Truncates a stream.
  54  *
  55  * Provides an interface for implementing seekable functionality on I/O Streams.
  56  **/
  57 struct _GSeekableIface
  58 {
  59   GTypeInterface g_iface;
  60
  61   /* Virtual Table */
  62
  63   goffset     (* tell)           (GSeekable    *seekable);
  64
  65   gboolean    (* can_seek)       (GSeekable    *seekable);
  66   gboolean    (* seek)           (GSeekable    *seekable,
  67                                   goffset       offset,
  68                                   GSeekType     type,
  69                                   GCancellable *cancellable,
  70                                   GError      **error);
  71
  72   gboolean    (* can_truncate)   (GSeekable    *seekable);
  73   gboolean    (* truncate_fn)    (GSeekable    *seekable,
  74                                   goffset       offset,
  75                                   GCancellable *cancellable,
  76                                   GError       **error);
  77
  78   /* TODO: Async seek/truncate */
  79 };
  80
  81 GType    g_seekable_get_type     (void) G_GNUC_CONST;
  82
  83 goffset  g_seekable_tell         (GSeekable     *seekable);
  84 gboolean g_seekable_can_seek     (GSeekable     *seekable);
  85 gboolean g_seekable_seek         (GSeekable     *seekable,
  86                                   goffset        offset,
  87                                   GSeekType      type,
  88                                   GCancellable  *cancellable,
  89                                   GError       **error);
  90 gboolean g_seekable_can_truncate (GSeekable     *seekable);
  91 gboolean g_seekable_truncate     (GSeekable     *seekable,
  92                                   goffset        offset,
  93                                   GCancellable  *cancellable,
  94                                   GError       **error);
  95
  96 G_END_DECLS
  97
  98
  99 #endif /* __G_SEEKABLE_H__ */