gseekable.c 4.76 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
/* GIO - GLib Input, Output and Streaming Library
 * 
 * Copyright (C) 2006-2007 Red Hat, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General
 * Public License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * Author: Alexander Larsson <alexl@redhat.com>
 */

23
#include "config.h"
24 25 26
#include "gseekable.h"
#include "glibintl.h"

27

28 29
/**
 * SECTION:gseekable
30
 * @short_description: Stream seeking interface
Matthias Clasen's avatar
Matthias Clasen committed
31
 * @include: gio/gio.h
32
 * @see_also: #GInputStream, #GOutputStream
33 34 35 36 37 38
 * 
 * #GSeekable is implemented by streams (implementations of 
 * #GInputStream or #GOutputStream) that support seeking.
 * 
 **/

Dan Winship's avatar
Dan Winship committed
39 40
typedef GSeekableIface GSeekableInterface;
G_DEFINE_INTERFACE (GSeekable, g_seekable, G_TYPE_OBJECT)
41 42

static void
Dan Winship's avatar
Dan Winship committed
43
g_seekable_default_init (GSeekableInterface *iface)
44 45 46 47 48
{
}

/**
 * g_seekable_tell:
49
 * @seekable: a #GSeekable.
50
 * 
51 52 53
 * Tells the current position within the stream.
 * 
 * Returns: the offset from the beginning of the buffer.
54 55 56 57 58 59 60 61 62 63 64 65 66 67 68
 **/
goffset
g_seekable_tell (GSeekable *seekable)
{
  GSeekableIface *iface;

  g_return_val_if_fail (G_IS_SEEKABLE (seekable), 0);

  iface = G_SEEKABLE_GET_IFACE (seekable);

  return (* iface->tell) (seekable);
}

/**
 * g_seekable_can_seek:
69 70 71
 * @seekable: a #GSeekable.
 * 
 * Tests if the stream supports the #GSeekableIface.
72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88
 * 
 * Returns: %TRUE if @seekable can be seeked. %FALSE otherwise.
 **/
gboolean
g_seekable_can_seek (GSeekable *seekable)
{
  GSeekableIface *iface;
  
  g_return_val_if_fail (G_IS_SEEKABLE (seekable), FALSE);

  iface = G_SEEKABLE_GET_IFACE (seekable);

  return (* iface->can_seek) (seekable);
}

/**
 * g_seekable_seek:
89 90 91
 * @seekable: a #GSeekable.
 * @offset: a #goffset.
 * @type: a #GSeekType.
92
 * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore. 
Matthias Clasen's avatar
Matthias Clasen committed
93
 * @error: a #GError location to store the error occurring, or %NULL to 
94
 * ignore.
95 96 97 98 99 100 101 102
 * 
 * Seeks in the stream by the given @offset, modified by @type.
 *
 * 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. 
 * 
 * Returns: %TRUE if successful. If an error
103
 *     has occurred, this function will return %FALSE and set @error
Matthias Clasen's avatar
Matthias Clasen committed
104
 *     appropriately if present.
105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123
 **/
gboolean
g_seekable_seek (GSeekable     *seekable,
		 goffset        offset,
		 GSeekType      type,
		 GCancellable  *cancellable,
		 GError       **error)
{
  GSeekableIface *iface;
  
  g_return_val_if_fail (G_IS_SEEKABLE (seekable), FALSE);

  iface = G_SEEKABLE_GET_IFACE (seekable);

  return (* iface->seek) (seekable, offset, type, cancellable, error);
}

/**
 * g_seekable_can_truncate:
124 125 126
 * @seekable: a #GSeekable.
 * 
 * Tests if the stream can be truncated.
127
 * 
128
 * Returns: %TRUE if the stream can be truncated, %FALSE otherwise.
129 130 131 132 133 134 135 136 137 138 139 140 141 142 143
 **/
gboolean
g_seekable_can_truncate (GSeekable *seekable)
{
  GSeekableIface *iface;
  
  g_return_val_if_fail (G_IS_SEEKABLE (seekable), FALSE);

  iface = G_SEEKABLE_GET_IFACE (seekable);

  return (* iface->can_truncate) (seekable);
}

/**
 * g_seekable_truncate:
144 145
 * @seekable: a #GSeekable.
 * @offset: a #goffset.
146
 * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore. 
Matthias Clasen's avatar
Matthias Clasen committed
147
 * @error: a #GError location to store the error occurring, or %NULL to 
148
 * ignore.
149 150 151 152 153 154 155 156
 * 
 * Truncates a stream with a given #offset. 
 * 
 * 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. If an
 * operation was partially finished when the operation was cancelled the
 * partial result will be returned, without an error.
157 158
 *
 * Virtual: truncate_fn
159
 * Returns: %TRUE if successful. If an error
160
 *     has occurred, this function will return %FALSE and set @error
Matthias Clasen's avatar
Matthias Clasen committed
161
 *     appropriately if present. 
162 163 164 165 166 167 168 169 170 171 172 173 174
 **/
gboolean
g_seekable_truncate (GSeekable     *seekable,
		     goffset        offset,
		     GCancellable  *cancellable,
		     GError       **error)
{
  GSeekableIface *iface;
  
  g_return_val_if_fail (G_IS_SEEKABLE (seekable), FALSE);

  iface = G_SEEKABLE_GET_IFACE (seekable);

175
  return (* iface->truncate_fn) (seekable, offset, cancellable, error);
176
}