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, see <http://www.gnu.org/licenses/>.
  17  *
  18  * Author: Alexander Larsson <alexl@redhat.com>
  19  */
  20
  21 #ifndef __G_SEEKABLE_H__
  22 #define __G_SEEKABLE_H__
  23
  24 #if !defined (__GIO_GIO_H_INSIDE__) && !defined (GIO_COMPILATION)
  25 #error "Only <gio/gio.h> can be included directly."
  26 #endif
  27
  28 #include <gio/giotypes.h>
  29
  30 G_BEGIN_DECLS
  31
  32 #define G_TYPE_SEEKABLE            (g_seekable_get_type ())
  33 #define G_SEEKABLE(obj)            (G_TYPE_CHECK_INSTANCE_CAST ((obj), G_TYPE_SEEKABLE, GSeekable))
  34 #define G_IS_SEEKABLE(obj)         (G_TYPE_CHECK_INSTANCE_TYPE ((obj), G_TYPE_SEEKABLE))
  35 #define G_SEEKABLE_GET_IFACE(obj)  (G_TYPE_INSTANCE_GET_INTERFACE ((obj), G_TYPE_SEEKABLE, GSeekableIface))
  36
  37 /**
  38  * GSeekable:
  39  *
  40  * Seek object for streaming operations.
  41  **/
  42 typedef struct _GSeekableIface   GSeekableIface;
  43
  44 /**
  45  * GSeekableIface:
  46  * @g_iface: The parent interface.
  47  * @tell: Tells the current location within a stream.
  48  * @can_seek: Checks if seeking is supported by the stream.
  49  * @seek: Seeks to a location within a stream.
  50  * @can_truncate: Checks if truncation is supported by the stream.
  51  * @truncate_fn: Truncates a stream.
  52  *
  53  * Provides an interface for implementing seekable functionality on I/O Streams.
  54  **/
  55 struct _GSeekableIface
  56 {
  57   GTypeInterface g_iface;
  58
  59   /* Virtual Table */
  60
  61   goffset     (* tell)           (GSeekable    *seekable);
  62
  63   gboolean    (* can_seek)       (GSeekable    *seekable);
  64   gboolean    (* seek)           (GSeekable    *seekable,
  65                                   goffset       offset,
  66                                   GSeekType     type,
  67                                   GCancellable *cancellable,
  68                                   GError      **error);
  69
  70   gboolean    (* can_truncate)   (GSeekable    *seekable);
  71   gboolean    (* truncate_fn)    (GSeekable    *seekable,
  72                                   goffset       offset,
  73                                   GCancellable *cancellable,
  74                                   GError       **error);
  75
  76   /* TODO: Async seek/truncate */
  77 };
  78
  79 GLIB_AVAILABLE_IN_ALL
  80 GType    g_seekable_get_type     (void) G_GNUC_CONST;
  81
  82 GLIB_AVAILABLE_IN_ALL
  83 goffset  g_seekable_tell         (GSeekable     *seekable);
  84 GLIB_AVAILABLE_IN_ALL
  85 gboolean g_seekable_can_seek     (GSeekable     *seekable);
  86 GLIB_AVAILABLE_IN_ALL
  87 gboolean g_seekable_seek         (GSeekable     *seekable,
  88                                   goffset        offset,
  89                                   GSeekType      type,
  90                                   GCancellable  *cancellable,
  91                                   GError       **error);
  92 GLIB_AVAILABLE_IN_ALL
  93 gboolean g_seekable_can_truncate (GSeekable     *seekable);
  94 GLIB_AVAILABLE_IN_ALL
  95 gboolean g_seekable_truncate     (GSeekable     *seekable,
  96                                   goffset        offset,
  97                                   GCancellable  *cancellable,
  98                                   GError       **error);
  99
 100 G_END_DECLS
 101
 102
 103 #endif /* __G_SEEKABLE_H__ */