1  /* GIO - GLib Input, Output and Streaming Library
       2   *
       3   * Copyright (C) 2006-2007 Red Hat, Inc.
       4   *
       5   * SPDX-License-Identifier: LGPL-2.1-or-later
       6   *
       7   * This library is free software; you can redistribute it and/or
       8   * modify it under the terms of the GNU Lesser General Public
       9   * License as published by the Free Software Foundation; either
      10   * version 2.1 of the License, or (at your option) any later version.
      11   *
      12   * This library is distributed in the hope that it will be useful,
      13   * but WITHOUT ANY WARRANTY; without even the implied warranty of
      14   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      15   * Lesser General Public License for more details.
      16   *
      17   * You should have received a copy of the GNU Lesser General
      18   * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
      19   *
      20   * Author: Alexander Larsson <alexl@redhat.com>
      21   */
      22  
      23  #ifndef __G_SEEKABLE_H__
      24  #define __G_SEEKABLE_H__
      25  
      26  #if !defined (__GIO_GIO_H_INSIDE__) && !defined (GIO_COMPILATION)
      27  #error "Only <gio/gio.h> can be included directly."
      28  #endif
      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  typedef struct _GSeekableIface   GSeekableIface;
      40  
      41  /**
      42   * GSeekableIface:
      43   * @g_iface: The parent interface.
      44   * @tell: Tells the current location within a stream.
      45   * @can_seek: Checks if seeking is supported by the stream.
      46   * @seek: Seeks to a location within a stream.
      47   * @can_truncate: Checks if truncation is supported by the stream.
      48   * @truncate_fn: Truncates a stream.
      49   *
      50   * Provides an interface for implementing seekable functionality on I/O Streams.
      51   **/
      52  struct _GSeekableIface
      53  {
      54    GTypeInterface g_iface;
      55  
      56    /* Virtual Table */
      57  
      58    goffset     (* tell)	         (GSeekable    *seekable);
      59  
      60    gboolean    (* can_seek)       (GSeekable    *seekable);
      61    gboolean    (* seek)	         (GSeekable    *seekable,
      62  				  goffset       offset,
      63  				  GSeekType     type,
      64  				  GCancellable *cancellable,
      65  				  GError      **error);
      66  
      67    gboolean    (* can_truncate)   (GSeekable    *seekable);
      68    gboolean    (* truncate_fn)    (GSeekable    *seekable,
      69  				  goffset       offset,
      70  				  GCancellable *cancellable,
      71  				  GError       **error);
      72  
      73    /* TODO: Async seek/truncate */
      74  };
      75  
      76  GIO_AVAILABLE_IN_ALL
      77  GType    g_seekable_get_type     (void) G_GNUC_CONST;
      78  
      79  GIO_AVAILABLE_IN_ALL
      80  goffset  g_seekable_tell         (GSeekable     *seekable);
      81  GIO_AVAILABLE_IN_ALL
      82  gboolean g_seekable_can_seek     (GSeekable     *seekable);
      83  GIO_AVAILABLE_IN_ALL
      84  gboolean g_seekable_seek         (GSeekable     *seekable,
      85  				  goffset        offset,
      86  				  GSeekType      type,
      87  				  GCancellable  *cancellable,
      88  				  GError       **error);
      89  GIO_AVAILABLE_IN_ALL
      90  gboolean g_seekable_can_truncate (GSeekable     *seekable);
      91  GIO_AVAILABLE_IN_ALL
      92  gboolean g_seekable_truncate     (GSeekable     *seekable,
      93  				  goffset        offset,
      94  				  GCancellable  *cancellable,
      95  				  GError       **error);
      96  
      97  G_END_DECLS
      98  
      99  
     100  #endif /* __G_SEEKABLE_H__ */