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 (at) 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 41 static void g_seekable_base_init (gpointer g_class); 42 43 44 GType 45 g_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 75 static void 76 g_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 **/ 88 goffset 89 g_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 **/ 108 gboolean 109 g_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 **/ 139 gboolean 140 g_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 **/ 163 gboolean 164 g_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 **/ 195 gboolean 196 g_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
