2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2000 Wim Taymans <wtay@chello.be>
5 * gstbuffer.c: Buffer operations
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
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 * Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 * Boston, MA 02111-1307, USA.
23 #include "gst_private.h"
25 #include "gstbuffer.h"
28 #include "gstminiobject.h"
31 static void gst_buffer_init (GTypeInstance * instance, gpointer g_class);
32 static void gst_buffer_class_init (gpointer g_class, gpointer class_data);
33 static void gst_buffer_finalize (GstBuffer * buffer);
34 static GstBuffer *_gst_buffer_copy (GstBuffer * buffer);
38 _gst_buffer_initialize (void)
42 gst_buffer_get_type ();
44 /* the GstMiniObject types need to be class_ref'd once before it can be
45 * done from multiple threads;
46 * see http://bugzilla.gnome.org/show_bug.cgi?id=304551 */
47 ptr = g_type_class_ref (GST_TYPE_BUFFER);
48 g_type_class_unref (ptr);
52 gst_buffer_get_type (void)
54 static GType _gst_buffer_type;
56 if (G_UNLIKELY (_gst_buffer_type == 0)) {
57 static const GTypeInfo buffer_info = {
58 sizeof (GstBufferClass),
61 gst_buffer_class_init,
70 _gst_buffer_type = g_type_register_static (GST_TYPE_MINI_OBJECT,
71 "GstBuffer", &buffer_info, 0);
73 return _gst_buffer_type;
77 gst_buffer_class_init (gpointer g_class, gpointer class_data)
79 GstBufferClass *buffer_class = GST_BUFFER_CLASS (g_class);
81 buffer_class->mini_object_class.copy =
82 (GstMiniObjectCopyFunction) _gst_buffer_copy;
83 buffer_class->mini_object_class.finalize =
84 (GstMiniObjectFinalizeFunction) gst_buffer_finalize;
89 gst_buffer_finalize (GstBuffer * buffer)
91 g_return_if_fail (buffer != NULL);
94 if (buffer->malloc_data) {
95 g_free (buffer->malloc_data);
98 gst_caps_replace (&GST_BUFFER_CAPS (buffer), NULL);
102 _gst_buffer_copy (GstBuffer * buffer)
107 g_return_val_if_fail (buffer != NULL, NULL);
109 /* create a fresh new buffer */
110 copy = gst_buffer_new ();
112 GST_CAT_LOG (GST_CAT_BUFFER, "copy %p to %p", buffer, copy);
114 /* copy relevant flags */
115 mask = GST_BUFFER_FLAG_PREROLL | GST_BUFFER_FLAG_IN_CAPS |
116 GST_BUFFER_FLAG_DELTA_UNIT;
117 GST_MINI_OBJECT (copy)->flags |= GST_MINI_OBJECT (buffer)->flags & mask;
119 /* we simply copy everything from our parent */
120 if (buffer->malloc_data) {
121 copy->malloc_data = g_memdup (buffer->data, buffer->size);
122 copy->data = copy->malloc_data;
125 copy->size = buffer->size;
127 GST_BUFFER_TIMESTAMP (copy) = GST_BUFFER_TIMESTAMP (buffer);
128 GST_BUFFER_DURATION (copy) = GST_BUFFER_DURATION (buffer);
129 GST_BUFFER_OFFSET (copy) = GST_BUFFER_OFFSET (buffer);
130 GST_BUFFER_OFFSET_END (copy) = GST_BUFFER_OFFSET_END (buffer);
132 if (GST_BUFFER_CAPS (buffer))
133 GST_BUFFER_CAPS (copy) = gst_caps_ref (GST_BUFFER_CAPS (buffer));
135 GST_BUFFER_CAPS (copy) = NULL;
141 gst_buffer_init (GTypeInstance * instance, gpointer g_class)
145 buffer = (GstBuffer *) instance;
147 GST_CAT_LOG (GST_CAT_BUFFER, "init %p", buffer);
149 GST_BUFFER_TIMESTAMP (buffer) = GST_CLOCK_TIME_NONE;
150 GST_BUFFER_DURATION (buffer) = GST_CLOCK_TIME_NONE;
151 GST_BUFFER_OFFSET (buffer) = GST_BUFFER_OFFSET_NONE;
152 GST_BUFFER_OFFSET_END (buffer) = GST_BUFFER_OFFSET_NONE;
158 * Creates a newly allocated buffer without any data.
160 * Returns: the new #GstBuffer.
165 gst_buffer_new (void)
169 newbuf = (GstBuffer *) gst_mini_object_new (GST_TYPE_BUFFER);
171 GST_CAT_LOG (GST_CAT_BUFFER, "new %p", newbuf);
177 * gst_buffer_new_and_alloc:
178 * @size: the size of the new buffer's data.
180 * Creates a newly allocated buffer with data of the given size.
182 * Returns: the new #GstBuffer.
187 gst_buffer_new_and_alloc (guint size)
191 newbuf = gst_buffer_new ();
193 newbuf->malloc_data = g_malloc (size);
194 GST_BUFFER_DATA (newbuf) = newbuf->malloc_data;
195 GST_BUFFER_SIZE (newbuf) = size;
202 * gst_buffer_get_caps:
203 * @buffer: a #GstBuffer to get the caps of.
205 * Gets the media type of the buffer. This can be NULL if there
206 * is not media type attached to this buffer or when the media
207 * type is the same as the previous received buffer.
209 * This function does not increment the refcount of the caps. The
210 * caps pointer will therefore remain valid until the buffer is
213 * Returns: the #GstCaps, or NULL if there was an error or there
214 * were no caps on this buffer.
216 /* FIXME can we make this threadsafe without a lock on the buffer?
217 * We can use compare and swap and atomic reads. */
219 gst_buffer_get_caps (GstBuffer * buffer)
221 g_return_val_if_fail (buffer != NULL, NULL);
223 return GST_BUFFER_CAPS (buffer);
227 * gst_buffer_set_caps:
228 * @buffer: a #GstBuffer to set the caps of.
229 * @caps: a #GstCaps to set.
231 * Sets the media type on the buffer. The caps' refcount will
232 * be increased and any previous caps on the buffer will be
235 /* FIXME can we make this threadsafe without a lock on the buffer?
236 * We can use compare and swap and atomic reads. Another idea is to
237 * not attach the caps to the buffer but use an event to signal a caps
240 gst_buffer_set_caps (GstBuffer * buffer, GstCaps * caps)
242 g_return_if_fail (buffer != NULL);
244 gst_caps_replace (&GST_BUFFER_CAPS (buffer), caps);
248 typedef struct _GstSubBuffer GstSubBuffer;
249 typedef struct _GstSubBufferClass GstSubBufferClass;
251 #define GST_TYPE_SUBBUFFER (gst_subbuffer_get_type())
253 #define GST_IS_SUBBUFFER(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_SUBBUFFER))
254 #define GST_SUBBUFFER(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_SUBBUFFER, GstSubBuffer))
263 struct _GstSubBufferClass
265 GstBufferClass buffer_class;
268 static GstBufferClass *sub_parent_class;
270 static void gst_subbuffer_init (GTypeInstance * instance, gpointer g_class);
271 static void gst_subbuffer_class_init (gpointer g_class, gpointer class_data);
272 static void gst_subbuffer_finalize (GstSubBuffer * buffer);
275 gst_subbuffer_get_type (void)
277 static GType _gst_subbuffer_type = 0;
279 if (G_UNLIKELY (_gst_subbuffer_type == 0)) {
280 static const GTypeInfo subbuffer_info = {
281 sizeof (GstSubBufferClass),
284 gst_subbuffer_class_init,
287 sizeof (GstSubBuffer),
293 _gst_subbuffer_type = g_type_register_static (GST_TYPE_BUFFER,
294 "GstSubBuffer", &subbuffer_info, 0);
296 return _gst_subbuffer_type;
300 gst_subbuffer_class_init (gpointer g_class, gpointer class_data)
302 GstBufferClass *buffer_class = GST_BUFFER_CLASS (g_class);
304 sub_parent_class = g_type_class_ref (GST_TYPE_BUFFER);
306 buffer_class->mini_object_class.finalize =
307 (GstMiniObjectFinalizeFunction) gst_subbuffer_finalize;
311 gst_subbuffer_finalize (GstSubBuffer * buffer)
313 gst_buffer_unref (buffer->parent);
315 GST_MINI_OBJECT_CLASS (sub_parent_class)->finalize (GST_MINI_OBJECT (buffer));
319 gst_subbuffer_init (GTypeInstance * instance, gpointer g_class)
324 * gst_buffer_create_subbuffer:
325 * @parent: a parent #GstBuffer to create a subbuffer from.
326 * @offset: the offset into parent #GstBuffer.
327 * @size: the size of the new #GstBuffer sub-buffer (with size > 0).
329 * Creates a sub-buffer from the parent at a given offset.
330 * This sub-buffer uses the actual memory space of the parent buffer.
331 * This function will copy the offset and timestamp field when the
332 * offset is 0, else they are set to _NONE.
333 * The duration field of the new buffer are set to GST_CLOCK_TIME_NONE.
335 * Returns: the new #GstBuffer, or NULL if there was an error.
340 gst_buffer_create_sub (GstBuffer * buffer, guint offset, guint size)
342 GstSubBuffer *subbuffer;
345 g_return_val_if_fail (buffer != NULL, NULL);
346 g_return_val_if_fail (buffer->mini_object.refcount > 0, NULL);
347 g_return_val_if_fail (size > 0, NULL);
348 g_return_val_if_fail (buffer->size >= offset + size, NULL);
350 /* find real parent */
351 if (GST_IS_SUBBUFFER (buffer)) {
352 parent = GST_SUBBUFFER (buffer)->parent;
356 gst_buffer_ref (parent);
358 /* create the new buffer */
359 subbuffer = (GstSubBuffer *) gst_mini_object_new (GST_TYPE_SUBBUFFER);
360 subbuffer->parent = parent;
362 GST_CAT_LOG (GST_CAT_BUFFER, "new subbuffer %p (parent %p)", subbuffer,
365 /* set the right values in the child */
366 GST_BUFFER_DATA (GST_BUFFER_CAST (subbuffer)) = buffer->data + offset;
367 GST_BUFFER_SIZE (GST_BUFFER_CAST (subbuffer)) = size;
369 /* we can copy the timestamp and offset if the new buffer starts at
372 GST_BUFFER_TIMESTAMP (subbuffer) = GST_BUFFER_TIMESTAMP (buffer);
373 GST_BUFFER_OFFSET (subbuffer) = GST_BUFFER_OFFSET (buffer);
375 GST_BUFFER_TIMESTAMP (subbuffer) = GST_CLOCK_TIME_NONE;
376 GST_BUFFER_OFFSET (subbuffer) = GST_BUFFER_OFFSET_NONE;
379 GST_BUFFER_DURATION (subbuffer) = GST_CLOCK_TIME_NONE;
380 GST_BUFFER_OFFSET_END (subbuffer) = GST_BUFFER_OFFSET_NONE;
382 GST_BUFFER_CAPS (subbuffer) = NULL;
384 return GST_BUFFER_CAST (subbuffer);
388 * gst_buffer_is_span_fast:
389 * @buf1: a first source #GstBuffer.
390 * @buf2: the second source #GstBuffer.
392 * Determines whether a gst_buffer_span() can be done without copying
393 * the contents, that is, whether the data areas are contiguous.
395 * Returns: TRUE if the buffers are contiguous,
396 * FALSE if a copy would be required.
401 gst_buffer_is_span_fast (GstBuffer * buf1, GstBuffer * buf2)
403 g_return_val_if_fail (buf1 != NULL && buf2 != NULL, FALSE);
404 g_return_val_if_fail (buf1->mini_object.refcount > 0, FALSE);
405 g_return_val_if_fail (buf2->mini_object.refcount > 0, FALSE);
407 /* it's only fast if we have subbuffers of the same parent */
408 return (GST_IS_SUBBUFFER (buf1) &&
409 GST_IS_SUBBUFFER (buf2) &&
410 (GST_SUBBUFFER (buf1)->parent == GST_SUBBUFFER (buf2)->parent) &&
411 ((buf1->data + buf1->size) == buf2->data));
416 * @buf1: a first source #GstBuffer to merge.
417 * @offset: the offset in the first buffer from where the new
418 * buffer should start.
419 * @buf2: the second source #GstBuffer to merge.
420 * @len: the total length of the new buffer.
422 * Creates a new buffer that consists of part of buf1 and buf2.
423 * Logically, buf1 and buf2 are concatenated into a single larger
424 * buffer, and a new buffer is created at the given offset inside
425 * this space, with a given length.
427 * If the two source buffers are children of the same larger buffer,
428 * and are contiguous, the new buffer will be a child of the shared
429 * parent, and thus no copying is necessary. you can use
430 * gst_buffer_is_span_fast() to determine if a memcpy will be needed.
432 * Returns: the new #GstBuffer that spans the two source buffers.
437 gst_buffer_span (GstBuffer * buf1, guint32 offset, GstBuffer * buf2,
442 g_return_val_if_fail (buf1 != NULL && buf2 != NULL, NULL);
443 g_return_val_if_fail (buf1->mini_object.refcount > 0, FALSE);
444 g_return_val_if_fail (buf2->mini_object.refcount > 0, FALSE);
445 g_return_val_if_fail (len > 0, NULL);
446 g_return_val_if_fail (len <= buf1->size + buf2->size - offset, NULL);
448 /* if the two buffers have the same parent and are adjacent */
449 if (gst_buffer_is_span_fast (buf1, buf2)) {
450 GstBuffer *parent = GST_SUBBUFFER (buf1)->parent;
452 /* we simply create a subbuffer of the common parent */
453 newbuf = gst_buffer_create_sub (parent,
454 buf1->data - parent->data + offset, len);
456 GST_CAT_DEBUG (GST_CAT_BUFFER,
457 "slow path taken while spanning buffers %p and %p", buf1, buf2);
458 /* otherwise we simply have to brute-force copy the buffers */
459 newbuf = gst_buffer_new_and_alloc (len);
461 /* copy the first buffer's data across */
462 memcpy (newbuf->data, buf1->data + offset, buf1->size - offset);
463 /* copy the second buffer's data across */
464 memcpy (newbuf->data + (buf1->size - offset), buf2->data,
465 len - (buf1->size - offset));
466 /* if the offset is 0, the new buffer has the same timestamp as buf1 */
468 GST_BUFFER_OFFSET (newbuf) = GST_BUFFER_OFFSET (buf1);
469 GST_BUFFER_TIMESTAMP (newbuf) = GST_BUFFER_TIMESTAMP (buf1);
472 /* if we completely merged the two buffers (appended), we can
473 * calculate the duration too. Also make sure we's not messing with
474 * invalid DURATIONS */
475 if (offset == 0 && buf1->size + buf2->size == len) {
476 if (GST_BUFFER_DURATION_IS_VALID (buf1) &&
477 GST_BUFFER_DURATION_IS_VALID (buf2)) {
479 GST_BUFFER_DURATION (newbuf) = GST_BUFFER_DURATION (buf1) +
480 GST_BUFFER_DURATION (buf2);
482 if (GST_BUFFER_OFFSET_END_IS_VALID (buf2)) {
484 GST_BUFFER_OFFSET_END (newbuf) = GST_BUFFER_OFFSET_END (buf2);