1 /* GStreamer
2 * Copyright (C) 2004 Benjamin Otte <otte@gnome.org>
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
13 *
14 * You should have received a copy of the GNU Library General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 02111-1307, USA.
18 */
20 #include "adapter.h"
21 #include <string.h>
23 /* default size for the assembled data buffer */
24 #define DEFAULT_SIZE 16
26 GST_DEBUG_CATEGORY_STATIC (gst_adapter_debug);
27 #define GST_CAT_DEFAULT gst_adapter_debug
29 #define _do_init(thing) \
30 GST_DEBUG_CATEGORY_INIT (gst_adapter_debug, "GstAdapter", 0, "object to splice and merge buffers to desired size")
31 GST_BOILERPLATE_FULL (GstAdapter, gst_adapter, GObject, G_TYPE_OBJECT, _do_init)
33 static void gst_adapter_dispose (GObject * object);
34 static void gst_adapter_finalize (GObject * object);
36 static void gst_adapter_base_init (gpointer g_class)
37 {
38 }
40 static void
41 gst_adapter_class_init (GstAdapterClass * klass)
42 {
43 GObjectClass *object = G_OBJECT_CLASS (klass);
45 object->dispose = gst_adapter_dispose;
46 object->finalize = gst_adapter_finalize;
47 }
49 static void
50 gst_adapter_init (GstAdapter * adapter)
51 {
52 adapter->assembled_data = g_malloc (DEFAULT_SIZE);
53 adapter->assembled_size = DEFAULT_SIZE;
54 }
56 static void
57 gst_adapter_dispose (GObject * object)
58 {
59 GstAdapter *adapter = GST_ADAPTER (object);
61 gst_adapter_clear (adapter);
63 GST_CALL_PARENT (G_OBJECT_CLASS, dispose, (object));
64 }
66 static void
67 gst_adapter_finalize (GObject * object)
68 {
69 GstAdapter *adapter = GST_ADAPTER (object);
71 g_free (adapter->assembled_data);
73 GST_CALL_PARENT (G_OBJECT_CLASS, finalize, (object));
74 }
76 /**
77 * gst_adapter_new:
78 *
79 * Creates a new #GstAdapter.
80 *
81 * Returns: a new #GstAdapter
82 */
83 GstAdapter *
84 gst_adapter_new (void)
85 {
86 return g_object_new (GST_TYPE_ADAPTER, NULL);
87 }
89 /**
90 * gst_adapter_clear:
91 * @adapter: the #GstAdapter to clear
92 *
93 * Removes all buffers from the @adapter.
94 */
95 void
96 gst_adapter_clear (GstAdapter * adapter)
97 {
98 g_return_if_fail (GST_IS_ADAPTER (adapter));
100 g_slist_foreach (adapter->buflist, (GFunc) gst_data_unref, NULL);
101 g_slist_free (adapter->buflist);
102 adapter->buflist = NULL;
103 adapter->size = 0;
104 adapter->skip = 0;
105 adapter->assembled_len = 0;
106 }
108 /**
109 * gst_adapter_push:
110 * @adapter: a #GstAdapter
111 * @buf: the #GstBuffer to queue into the adapter
112 *
113 * Adds the data from @buf to the data stored inside @adapter and takes
114 * ownership of the buffer.
115 */
116 void
117 gst_adapter_push (GstAdapter * adapter, GstBuffer * buf)
118 {
119 g_return_if_fail (GST_IS_ADAPTER (adapter));
120 g_return_if_fail (GST_IS_BUFFER (buf));
122 adapter->size += GST_BUFFER_SIZE (buf);
123 adapter->buflist = g_slist_append (adapter->buflist, buf);
124 }
126 /**
127 * gst_adapter_peek:
128 * @adapter: a #GstAdapter
129 * @size: number of bytes to peek
130 *
131 * Gets the first @size bytes stored in the @adapter. If this many bytes are
132 * not available, it returns NULL. The returned pointer is valid until the next
133 * function is called on the adapter.
134 *
135 * Returns: a pointer to the first @size bytes of data or NULL
136 */
137 const guint8 *
138 gst_adapter_peek (GstAdapter * adapter, guint size)
139 {
140 GstBuffer *cur;
141 GSList *cur_list;
142 guint copied;
144 g_return_val_if_fail (GST_IS_ADAPTER (adapter), NULL);
145 g_return_val_if_fail (size > 0, NULL);
147 if (size > adapter->size)
148 return NULL;
150 if (adapter->assembled_len >= size)
151 return adapter->assembled_data;
153 cur = adapter->buflist->data;
154 if (GST_BUFFER_SIZE (cur) >= size + adapter->skip)
155 return GST_BUFFER_DATA (cur) + adapter->skip;
157 if (adapter->assembled_size < size) {
158 adapter->assembled_size = (size / DEFAULT_SIZE + 1) * DEFAULT_SIZE;
159 GST_DEBUG_OBJECT (adapter, "setting size of internal buffer to %u\n",
160 adapter->assembled_size);
161 adapter->assembled_data =
162 g_realloc (adapter->assembled_data, adapter->assembled_size);
163 }
164 adapter->assembled_len = size;
165 copied = GST_BUFFER_SIZE (cur) - adapter->skip;
166 memcpy (adapter->assembled_data, GST_BUFFER_DATA (cur) + adapter->skip,
167 copied);
168 cur_list = g_slist_next (adapter->buflist);
169 while (copied < size) {
170 g_assert (cur_list);
171 cur = cur_list->data;
172 cur_list = g_slist_next (cur_list);
173 memcpy (adapter->assembled_data + copied, GST_BUFFER_DATA (cur),
174 MIN (GST_BUFFER_SIZE (cur), size - copied));
175 copied = MIN (size, copied + GST_BUFFER_SIZE (cur));
176 }
178 return adapter->assembled_data;
179 }
181 /**
182 * gst_adapter_flush:
183 * @adapter: a #GstAdapter
184 * @flush: number of bytes to flush
185 *
186 * Flushes the first @flush bytes of the @adapter.
187 */
188 void
189 gst_adapter_flush (GstAdapter * adapter, guint flush)
190 {
191 GstBuffer *cur;
193 g_return_if_fail (GST_IS_ADAPTER (adapter));
194 g_return_if_fail (flush > 0);
195 g_return_if_fail (flush <= adapter->size);
197 GST_LOG_OBJECT (adapter, "flushing %u bytes\n", flush);
198 adapter->size -= flush;
199 adapter->assembled_len = 0;
200 while (flush > 0) {
201 cur = adapter->buflist->data;
202 if (GST_BUFFER_SIZE (cur) <= flush + adapter->skip) {
203 /* can skip whole buffer */
204 flush -= GST_BUFFER_SIZE (cur) - adapter->skip;
205 adapter->skip = 0;
206 adapter->buflist = g_slist_remove (adapter->buflist, cur);
207 gst_data_unref (GST_DATA (cur));
208 } else {
209 adapter->skip += flush;
210 break;
211 }
212 }
213 }
215 /**
216 * gst_adapter_available:
217 * @adapter: a #GstAdapter
218 *
219 * Gets the maximum amount of bytes available, that is it returns the maximum
220 * value that can be supplied to gst_adapter_peek() without that function
221 * returning NULL.
222 *
223 * Returns: amount of bytes available in @adapter
224 */
225 guint
226 gst_adapter_available (GstAdapter * adapter)
227 {
228 g_return_val_if_fail (GST_IS_ADAPTER (adapter), 0);
230 return adapter->size;
231 }
233 /**
234 * gst_adapter_available_fast:
235 * @adapter: a #GstAdapter
236 *
237 * Gets the maximum amount of bytes available without the need to do expensive
238 * operations (like copying the data into a temporary buffer).
239 *
240 * Returns: amount of bytes available in @adapter without expensive operations
241 */
242 guint
243 gst_adapter_available_fast (GstAdapter * adapter)
244 {
245 g_return_val_if_fail (GST_IS_ADAPTER (adapter), 0);
247 if (!adapter->buflist)
248 return 0;
249 if (adapter->assembled_len)
250 return adapter->assembled_len;
251 g_assert (GST_BUFFER_SIZE (adapter->buflist->data) > adapter->skip);
252 return GST_BUFFER_SIZE (adapter->buflist->data) - adapter->skip;
253 }