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#include "config.h"
24#include "gseekable.h"
25#include "glibintl.h"
26
27#include "gioalias.h"
28
29/**
30 * SECTION:gseekable
31 * @short_description: Stream seeking interface
32 * @include: gio/gio.h
33 * @see_also: #GInputStream, #GOutputStream
34 *
35 * #GSeekable is implemented by streams (implementations of
36 * #GInputStream or #GOutputStream) that support seeking.
37 *
38 **/
39
40
41static void g_seekable_base_init (gpointer g_class);
42
43
44GType
45g_seekable_get_type (void)
46{
47  static volatile gsize g_define_type_id__volatile = 0;
48
49  if (g_once_init_enter (&g_define_type_id__volatile))
50    {
51      const GTypeInfo seekable_info =
52      {
53        sizeof (GSeekableIface), /* class_size */
54	g_seekable_base_init,   /* base_init */
55	NULL,		/* base_finalize */
56	NULL,
57	NULL,		/* class_finalize */
58	NULL,		/* class_data */
59	0,
60	0,              /* n_preallocs */
61	NULL
62      };
63      GType g_define_type_id =
64	g_type_register_static (G_TYPE_INTERFACE, I_("GSeekable"),
65				&seekable_info, 0);
66
67      g_type_interface_add_prerequisite (g_define_type_id, G_TYPE_OBJECT);
68
69      g_once_init_leave (&g_define_type_id__volatile, g_define_type_id);
70    }
71
72  return g_define_type_id__volatile;
73}
74
75static void
76g_seekable_base_init (gpointer g_class)
77{
78}
79
80/**
81 * g_seekable_tell:
82 * @seekable: a #GSeekable.
83 *
84 * Tells the current position within the stream.
85 *
86 * Returns: the offset from the beginning of the buffer.
87 **/
88goffset
89g_seekable_tell (GSeekable *seekable)
90{
91  GSeekableIface *iface;
92
93  g_return_val_if_fail (G_IS_SEEKABLE (seekable), 0);
94
95  iface = G_SEEKABLE_GET_IFACE (seekable);
96
97  return (* iface->tell) (seekable);
98}
99
100/**
101 * g_seekable_can_seek:
102 * @seekable: a #GSeekable.
103 *
104 * Tests if the stream supports the #GSeekableIface.
105 *
106 * Returns: %TRUE if @seekable can be seeked. %FALSE otherwise.
107 **/
108gboolean
109g_seekable_can_seek (GSeekable *seekable)
110{
111  GSeekableIface *iface;
112
113  g_return_val_if_fail (G_IS_SEEKABLE (seekable), FALSE);
114
115  iface = G_SEEKABLE_GET_IFACE (seekable);
116
117  return (* iface->can_seek) (seekable);
118}
119
120/**
121 * g_seekable_seek:
122 * @seekable: a #GSeekable.
123 * @offset: a #goffset.
124 * @type: a #GSeekType.
125 * @cancellable: optional #GCancellable object, %NULL to ignore.
126 * @error: a #GError location to store the error occuring, or %NULL to
127 * ignore.
128 *
129 * Seeks in the stream by the given @offset, modified by @type.
130 *
131 * If @cancellable is not %NULL, then the operation can be cancelled by
132 * triggering the cancellable object from another thread. If the operation
133 * was cancelled, the error %G_IO_ERROR_CANCELLED will be returned.
134 *
135 * Returns: %TRUE if successful. If an error
136 *     has occurred, this function will return %FALSE and set @error
137 *     appropriately if present.
138 **/
139gboolean
140g_seekable_seek (GSeekable     *seekable,
141		 goffset        offset,
142		 GSeekType      type,
143		 GCancellable  *cancellable,
144		 GError       **error)
145{
146  GSeekableIface *iface;
147
148  g_return_val_if_fail (G_IS_SEEKABLE (seekable), FALSE);
149
150  iface = G_SEEKABLE_GET_IFACE (seekable);
151
152  return (* iface->seek) (seekable, offset, type, cancellable, error);
153}
154
155/**
156 * g_seekable_can_truncate:
157 * @seekable: a #GSeekable.
158 *
159 * Tests if the stream can be truncated.
160 *
161 * Returns: %TRUE if the stream can be truncated, %FALSE otherwise.
162 **/
163gboolean
164g_seekable_can_truncate (GSeekable *seekable)
165{
166  GSeekableIface *iface;
167
168  g_return_val_if_fail (G_IS_SEEKABLE (seekable), FALSE);
169
170  iface = G_SEEKABLE_GET_IFACE (seekable);
171
172  return (* iface->can_truncate) (seekable);
173}
174
175/**
176 * g_seekable_truncate:
177 * @seekable: a #GSeekable.
178 * @offset: a #goffset.
179 * @cancellable: optional #GCancellable object, %NULL to ignore.
180 * @error: a #GError location to store the error occuring, or %NULL to
181 * ignore.
182 *
183 * Truncates a stream with a given #offset.
184 *
185 * If @cancellable is not %NULL, then the operation can be cancelled by
186 * triggering the cancellable object from another thread. If the operation
187 * was cancelled, the error %G_IO_ERROR_CANCELLED will be returned. If an
188 * operation was partially finished when the operation was cancelled the
189 * partial result will be returned, without an error.
190 *
191 * Returns: %TRUE if successful. If an error
192 *     has occurred, this function will return %FALSE and set @error
193 *     appropriately if present.
194 **/
195gboolean
196g_seekable_truncate (GSeekable     *seekable,
197		     goffset        offset,
198		     GCancellable  *cancellable,
199		     GError       **error)
200{
201  GSeekableIface *iface;
202
203  g_return_val_if_fail (G_IS_SEEKABLE (seekable), FALSE);
204
205  iface = G_SEEKABLE_GET_IFACE (seekable);
206
207  return (* iface->truncate_fn) (seekable, offset, cancellable, error);
208}
209
210#define __G_SEEKABLE_C__
211#include "gioaliasdef.c"
212