2 * Copyright (C) 2004 Benjamin Otte <otte@gnome.org>
3 * 2005 Wim Taymans <wim@fluendo.com>
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Library 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.
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 * Library General Public License for more details.
15 * You should have received a copy of the GNU Library General Public
16 * License along with this library; if not, write to the
17 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
18 * Boston, MA 02110-1301, USA.
23 * @short_description: adapts incoming data on a sink pad into chunks of N bytes
25 * This class is for elements that receive buffers in an undesired size.
26 * While for example raw video contains one image per buffer, the same is not
27 * true for a lot of other formats, especially those that come directly from
28 * a file. So if you have undefined buffer sizes and require a specific size,
29 * this object is for you.
31 * An adapter is created with gst_adapter_new(). It can be freed again with
34 * The theory of operation is like this: All buffers received are put
35 * into the adapter using gst_adapter_push() and the data is then read back
36 * in chunks of the desired size using gst_adapter_map()/gst_adapter_unmap()
37 * and/or gst_adapter_copy(). After the data has been processed, it is freed
38 * using gst_adapter_unmap().
40 * Other methods such as gst_adapter_take() and gst_adapter_take_buffer()
41 * combine gst_adapter_map() and gst_adapter_unmap() in one method and are
42 * potentially more convenient for some use cases.
44 * For example, a sink pad's chain function that needs to pass data to a library
45 * in 512-byte chunks could be implemented like this:
47 * static GstFlowReturn
48 * sink_pad_chain (GstPad *pad, GstObject *parent, GstBuffer *buffer)
51 * GstAdapter *adapter;
52 * GstFlowReturn ret = GST_FLOW_OK;
54 * this = MY_ELEMENT (parent);
56 * adapter = this->adapter;
58 * // put buffer into adapter
59 * gst_adapter_push (adapter, buffer);
61 * // while we can read out 512 bytes, process them
62 * while (gst_adapter_available (adapter) >= 512 && ret == GST_FLOW_OK) {
63 * const guint8 *data = gst_adapter_map (adapter, 512);
64 * // use flowreturn as an error value
65 * ret = my_library_foo (data);
66 * gst_adapter_unmap (adapter);
67 * gst_adapter_flush (adapter, 512);
73 * For another example, a simple element inside GStreamer that uses GstAdapter
74 * is the libvisual element.
76 * An element using GstAdapter in its sink pad chain function should ensure that
77 * when the FLUSH_STOP event is received, that any queued data is cleared using
78 * gst_adapter_clear(). Data should also be cleared or processed on EOS and
79 * when changing state from #GST_STATE_PAUSED to #GST_STATE_READY.
81 * Also check the GST_BUFFER_FLAG_DISCONT flag on the buffer. Some elements might
82 * need to clear the adapter after a discontinuity.
84 * The adapter will keep track of the timestamps of the buffers
85 * that were pushed. The last seen timestamp before the current position
86 * can be queried with gst_adapter_prev_pts(). This function can
87 * optionally return the number of bytes between the start of the buffer that
88 * carried the timestamp and the current adapter position. The distance is
89 * useful when dealing with, for example, raw audio samples because it allows
90 * you to calculate the timestamp of the current adapter position by using the
91 * last seen timestamp and the amount of bytes since. Additionally, the
92 * gst_adapter_prev_pts_at_offset() can be used to determine the last
93 * seen timestamp at a particular offset in the adapter.
95 * A last thing to note is that while GstAdapter is pretty optimized,
96 * merging buffers still might be an operation that requires a malloc() and
97 * memcpy() operation, and these operations are not the fastest. Because of
98 * this, some functions like gst_adapter_available_fast() are provided to help
99 * speed up such cases should you want to. To avoid repeated memory allocations,
100 * gst_adapter_copy() can be used to copy data into a (statically allocated)
101 * user provided buffer.
103 * GstAdapter is not MT safe. All operations on an adapter must be serialized by
104 * the caller. This is not normally a problem, however, as the normal use case
105 * of GstAdapter is inside one pad's chain function, in which case access is
106 * serialized via the pad's STREAM_LOCK.
108 * Note that gst_adapter_push() takes ownership of the buffer passed. Use
109 * gst_buffer_ref() before pushing it into the adapter if you still want to
110 * access the buffer later. The adapter will never modify the data in the
111 * buffer pushed in it.
113 * Last reviewed on 2009-05-13 (0.10.24).
116 #include <gst/gst_private.h>
117 #include "gstadapter.h"
120 /* default size for the assembled data buffer */
121 #define DEFAULT_SIZE 4096
123 static void gst_adapter_flush_unchecked (GstAdapter * adapter, gsize flush);
125 GST_DEBUG_CATEGORY_STATIC (gst_adapter_debug);
126 #define GST_CAT_DEFAULT gst_adapter_debug
138 /* we keep state of assembled pieces */
139 gpointer assembled_data;
140 gsize assembled_size;
144 guint64 pts_distance;
146 guint64 dts_distance;
154 struct _GstAdapterClass
156 GObjectClass parent_class;
160 GST_DEBUG_CATEGORY_INIT (gst_adapter_debug, "adapter", 0, "object to splice and merge buffers to desired size")
161 #define gst_adapter_parent_class parent_class
162 G_DEFINE_TYPE_WITH_CODE (GstAdapter, gst_adapter, G_TYPE_OBJECT, _do_init);
164 static void gst_adapter_dispose (GObject * object);
165 static void gst_adapter_finalize (GObject * object);
168 gst_adapter_class_init (GstAdapterClass * klass)
170 GObjectClass *object = G_OBJECT_CLASS (klass);
172 object->dispose = gst_adapter_dispose;
173 object->finalize = gst_adapter_finalize;
177 gst_adapter_init (GstAdapter * adapter)
179 adapter->assembled_data = g_malloc (DEFAULT_SIZE);
180 adapter->assembled_size = DEFAULT_SIZE;
181 adapter->pts = GST_CLOCK_TIME_NONE;
182 adapter->pts_distance = 0;
183 adapter->dts = GST_CLOCK_TIME_NONE;
184 adapter->dts_distance = 0;
188 gst_adapter_dispose (GObject * object)
190 GstAdapter *adapter = GST_ADAPTER (object);
192 gst_adapter_clear (adapter);
194 GST_CALL_PARENT (G_OBJECT_CLASS, dispose, (object));
198 gst_adapter_finalize (GObject * object)
200 GstAdapter *adapter = GST_ADAPTER (object);
202 g_free (adapter->assembled_data);
204 GST_CALL_PARENT (G_OBJECT_CLASS, finalize, (object));
210 * Creates a new #GstAdapter. Free with g_object_unref().
212 * Returns: (transfer full): a new #GstAdapter
215 gst_adapter_new (void)
217 return g_object_newv (GST_TYPE_ADAPTER, 0, NULL);
222 * @adapter: a #GstAdapter
224 * Removes all buffers from @adapter.
227 gst_adapter_clear (GstAdapter * adapter)
229 g_return_if_fail (GST_IS_ADAPTER (adapter));
231 if (adapter->info.memory)
232 gst_adapter_unmap (adapter);
234 g_slist_foreach (adapter->buflist, (GFunc) gst_mini_object_unref, NULL);
235 g_slist_free (adapter->buflist);
236 adapter->buflist = NULL;
237 adapter->buflist_end = NULL;
240 adapter->assembled_len = 0;
241 adapter->pts = GST_CLOCK_TIME_NONE;
242 adapter->pts_distance = 0;
243 adapter->dts = GST_CLOCK_TIME_NONE;
244 adapter->dts_distance = 0;
245 adapter->scan_offset = 0;
246 adapter->scan_entry = NULL;
250 update_timestamps (GstAdapter * adapter, GstBuffer * buf)
252 GstClockTime pts, dts;
254 pts = GST_BUFFER_PTS (buf);
255 if (GST_CLOCK_TIME_IS_VALID (pts)) {
256 GST_LOG_OBJECT (adapter, "new pts %" GST_TIME_FORMAT, GST_TIME_ARGS (pts));
258 adapter->pts_distance = 0;
260 dts = GST_BUFFER_DTS (buf);
261 if (GST_CLOCK_TIME_IS_VALID (dts)) {
262 GST_LOG_OBJECT (adapter, "new dts %" GST_TIME_FORMAT, GST_TIME_ARGS (dts));
264 adapter->dts_distance = 0;
268 /* copy data into @dest, skipping @skip bytes from the head buffers */
270 copy_into_unchecked (GstAdapter * adapter, guint8 * dest, gsize skip,
277 /* first step, do skipping */
278 /* we might well be copying where we were scanning */
279 if (adapter->scan_entry && (adapter->scan_offset <= skip)) {
280 g = adapter->scan_entry;
281 skip -= adapter->scan_offset;
283 g = adapter->buflist;
286 bsize = gst_buffer_get_size (buf);
287 while (G_UNLIKELY (skip >= bsize)) {
289 g = g_slist_next (g);
291 bsize = gst_buffer_get_size (buf);
293 /* copy partial buffer */
294 csize = MIN (bsize - skip, size);
295 GST_DEBUG ("bsize %" G_GSIZE_FORMAT ", skip %" G_GSIZE_FORMAT ", csize %"
296 G_GSIZE_FORMAT, bsize, skip, csize);
297 GST_CAT_LOG_OBJECT (GST_CAT_PERFORMANCE, adapter, "extract %" G_GSIZE_FORMAT
299 gst_buffer_extract (buf, skip, dest, csize);
303 /* second step, copy remainder */
305 g = g_slist_next (g);
307 bsize = gst_buffer_get_size (buf);
308 if (G_LIKELY (bsize > 0)) {
309 csize = MIN (bsize, size);
310 GST_CAT_LOG_OBJECT (GST_CAT_PERFORMANCE, adapter,
311 "extract %" G_GSIZE_FORMAT " bytes", csize);
312 gst_buffer_extract (buf, 0, dest, csize);
321 * @adapter: a #GstAdapter
322 * @buf: (transfer full): a #GstBuffer to add to queue in the adapter
324 * Adds the data from @buf to the data stored inside @adapter and takes
325 * ownership of the buffer.
328 gst_adapter_push (GstAdapter * adapter, GstBuffer * buf)
332 g_return_if_fail (GST_IS_ADAPTER (adapter));
333 g_return_if_fail (GST_IS_BUFFER (buf));
335 size = gst_buffer_get_size (buf);
336 adapter->size += size;
338 /* Note: merging buffers at this point is premature. */
339 if (G_UNLIKELY (adapter->buflist == NULL)) {
340 GST_LOG_OBJECT (adapter, "pushing %p first %" G_GSIZE_FORMAT " bytes",
342 adapter->buflist = adapter->buflist_end = g_slist_append (NULL, buf);
343 update_timestamps (adapter, buf);
345 /* Otherwise append to the end, and advance our end pointer */
346 GST_LOG_OBJECT (adapter, "pushing %p %" G_GSIZE_FORMAT " bytes at end, "
347 "size now %" G_GSIZE_FORMAT, buf, size, adapter->size);
348 adapter->buflist_end = g_slist_append (adapter->buflist_end, buf);
349 adapter->buflist_end = g_slist_next (adapter->buflist_end);
354 /* Internal method only. Tries to merge buffers at the head of the queue
355 * to form a single larger buffer of size 'size'.
357 * Returns TRUE if it managed to merge anything.
360 gst_adapter_try_to_merge_up (GstAdapter * adapter, gsize size)
362 GstBuffer *cur, *head;
364 gboolean ret = FALSE;
367 g = adapter->buflist;
373 hsize = gst_buffer_get_size (head);
375 /* Remove skipped part from the buffer (otherwise the buffer might grow indefinitely) */
376 head = gst_buffer_make_writable (head);
377 gst_buffer_resize (head, adapter->skip, hsize - adapter->skip);
378 hsize -= adapter->skip;
382 g = g_slist_next (g);
384 while (g != NULL && hsize < size) {
386 /* Merge the head buffer and the next in line */
387 GST_LOG_OBJECT (adapter, "Merging buffers of size %" G_GSIZE_FORMAT " & %"
388 G_GSIZE_FORMAT " in search of target %" G_GSIZE_FORMAT,
389 hsize, gst_buffer_get_size (cur), size);
391 head = gst_buffer_append (head, cur);
392 hsize = gst_buffer_get_size (head);
395 /* Delete the front list item, and store our new buffer in the 2nd list
397 adapter->buflist = g_slist_delete_link (adapter->buflist, adapter->buflist);
400 /* invalidate scan position */
401 adapter->scan_offset = 0;
402 adapter->scan_entry = NULL;
404 g = g_slist_next (g);
413 * @adapter: a #GstAdapter
414 * @size: the number of bytes to map/peek
416 * Gets the first @size bytes stored in the @adapter. The returned pointer is
417 * valid until the next function is called on the adapter.
419 * Note that setting the returned pointer as the data of a #GstBuffer is
420 * incorrect for general-purpose plugins. The reason is that if a downstream
421 * element stores the buffer so that it has access to it outside of the bounds
422 * of its chain function, the buffer will have an invalid data pointer after
423 * your element flushes the bytes. In that case you should use
424 * gst_adapter_take(), which returns a freshly-allocated buffer that you can set
425 * as #GstBuffer memory or the potentially more performant
426 * gst_adapter_take_buffer().
428 * Returns #NULL if @size bytes are not available.
430 * Returns: (transfer none) (array length=size) (element-type guint8):
431 * a pointer to the first @size bytes of data, or NULL
434 gst_adapter_map (GstAdapter * adapter, gsize size)
438 gsize toreuse, tocopy;
441 g_return_val_if_fail (GST_IS_ADAPTER (adapter), NULL);
442 g_return_val_if_fail (size > 0, NULL);
444 if (adapter->info.memory)
445 gst_adapter_unmap (adapter);
447 /* we don't have enough data, return NULL. This is unlikely
448 * as one usually does an _available() first instead of peeking a
450 if (G_UNLIKELY (size > adapter->size))
453 /* we have enough assembled data, return it */
454 if (adapter->assembled_len >= size)
455 return adapter->assembled_data;
460 cur = adapter->buflist->data;
461 skip = adapter->skip;
463 csize = gst_buffer_get_size (cur);
464 if (csize >= size + skip) {
465 if (!gst_buffer_map (cur, &adapter->info, GST_MAP_READ))
468 return (guint8 *) adapter->info.data + skip;
470 /* We may be able to efficiently merge buffers in our pool to
471 * gather a big enough chunk to return it from the head buffer directly */
473 } while (gst_adapter_try_to_merge_up (adapter, size));
476 /* see how much data we can reuse from the assembled memory and how much
478 toreuse = adapter->assembled_len;
479 tocopy = size - toreuse;
481 /* Gonna need to copy stuff out */
482 if (G_UNLIKELY (adapter->assembled_size < size)) {
483 adapter->assembled_size = (size / DEFAULT_SIZE + 1) * DEFAULT_SIZE;
484 GST_DEBUG_OBJECT (adapter, "resizing internal buffer to %" G_GSIZE_FORMAT,
485 adapter->assembled_size);
487 GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "alloc new buffer");
488 /* no g_realloc to avoid a memcpy that is not desired here since we are
489 * not going to reuse any data here */
490 g_free (adapter->assembled_data);
491 adapter->assembled_data = g_malloc (adapter->assembled_size);
493 /* we are going to reuse all data, realloc then */
494 GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "reusing %" G_GSIZE_FORMAT " bytes",
496 adapter->assembled_data =
497 g_realloc (adapter->assembled_data, adapter->assembled_size);
500 GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "copy remaining %" G_GSIZE_FORMAT
501 " bytes from adapter", tocopy);
502 data = adapter->assembled_data;
503 copy_into_unchecked (adapter, data + toreuse, skip + toreuse, tocopy);
504 adapter->assembled_len = size;
506 return adapter->assembled_data;
511 * @adapter: a #GstAdapter
513 * Releases the memory obtained with the last gst_adapter_map().
516 gst_adapter_unmap (GstAdapter * adapter)
518 g_return_if_fail (GST_IS_ADAPTER (adapter));
520 if (adapter->info.memory) {
521 GstBuffer *cur = adapter->buflist->data;
522 GST_LOG_OBJECT (adapter, "unmap memory buffer %p", cur);
523 gst_buffer_unmap (cur, &adapter->info);
524 adapter->info.memory = NULL;
530 * @adapter: a #GstAdapter
531 * @dest: (out caller-allocates) (array length=size) (element-type guint8):
532 * the memory to copy into
533 * @offset: the bytes offset in the adapter to start from
534 * @size: the number of bytes to copy
536 * Copies @size bytes of data starting at @offset out of the buffers
537 * contained in @GstAdapter into an array @dest provided by the caller.
539 * The array @dest should be large enough to contain @size bytes.
540 * The user should check that the adapter has (@offset + @size) bytes
541 * available before calling this function.
544 gst_adapter_copy (GstAdapter * adapter, gpointer dest, gsize offset, gsize size)
546 g_return_if_fail (GST_IS_ADAPTER (adapter));
547 g_return_if_fail (size > 0);
548 g_return_if_fail (offset + size <= adapter->size);
550 copy_into_unchecked (adapter, dest, offset + adapter->skip, size);
553 /*Flushes the first @flush bytes in the @adapter*/
555 gst_adapter_flush_unchecked (GstAdapter * adapter, gsize flush)
561 GST_LOG_OBJECT (adapter, "flushing %" G_GSIZE_FORMAT " bytes", flush);
563 if (adapter->info.memory)
564 gst_adapter_unmap (adapter);
567 adapter->size -= flush;
568 adapter->assembled_len = 0;
570 /* take skip into account */
571 flush += adapter->skip;
572 /* distance is always at least the amount of skipped bytes */
573 adapter->pts_distance -= adapter->skip;
574 adapter->dts_distance -= adapter->skip;
576 g = adapter->buflist;
578 size = gst_buffer_get_size (cur);
579 while (flush >= size) {
580 /* can skip whole buffer */
581 GST_LOG_OBJECT (adapter, "flushing out head buffer");
582 adapter->pts_distance += size;
583 adapter->dts_distance += size;
586 gst_buffer_unref (cur);
587 g = g_slist_delete_link (g, g);
589 if (G_UNLIKELY (g == NULL)) {
590 GST_LOG_OBJECT (adapter, "adapter empty now");
591 adapter->buflist_end = NULL;
594 /* there is a new head buffer, update the timestamps */
596 update_timestamps (adapter, cur);
597 size = gst_buffer_get_size (cur);
599 adapter->buflist = g;
600 /* account for the remaining bytes */
601 adapter->skip = flush;
602 adapter->pts_distance += flush;
603 adapter->dts_distance += flush;
604 /* invalidate scan position */
605 adapter->scan_offset = 0;
606 adapter->scan_entry = NULL;
611 * @adapter: a #GstAdapter
612 * @flush: the number of bytes to flush
614 * Flushes the first @flush bytes in the @adapter. The caller must ensure that
615 * at least this many bytes are available.
617 * See also: gst_adapter_map(), gst_adapter_unmap()
620 gst_adapter_flush (GstAdapter * adapter, gsize flush)
622 g_return_if_fail (GST_IS_ADAPTER (adapter));
623 g_return_if_fail (flush <= adapter->size);
625 /* flushing out 0 bytes will do nothing */
626 if (G_UNLIKELY (flush == 0))
629 gst_adapter_flush_unchecked (adapter, flush);
632 /* internal function, nbytes should be flushed after calling this function */
634 gst_adapter_take_internal (GstAdapter * adapter, gsize nbytes)
637 gsize toreuse, tocopy;
639 /* see how much data we can reuse from the assembled memory and how much
641 toreuse = MIN (nbytes, adapter->assembled_len);
642 tocopy = nbytes - toreuse;
644 /* find memory to return */
645 if (adapter->assembled_size >= nbytes && toreuse > 0) {
646 /* we reuse already allocated memory but only when we're going to reuse
647 * something from it because else we are worse than the malloc and copy
649 GST_LOG_OBJECT (adapter, "reusing %" G_GSIZE_FORMAT " bytes of assembled"
651 /* we have enough free space in the assembled array */
652 data = adapter->assembled_data;
653 /* flush after this function should set the assembled_size to 0 */
654 adapter->assembled_data = g_malloc (adapter->assembled_size);
656 GST_LOG_OBJECT (adapter, "allocating %" G_GSIZE_FORMAT " bytes", nbytes);
657 /* not enough bytes in the assembled array, just allocate new space */
658 data = g_malloc (nbytes);
659 /* reuse what we can from the already assembled data */
661 GST_LOG_OBJECT (adapter, "reusing %" G_GSIZE_FORMAT " bytes", toreuse);
662 GST_CAT_LOG_OBJECT (GST_CAT_PERFORMANCE, adapter,
663 "memcpy %" G_GSIZE_FORMAT " bytes", toreuse);
664 memcpy (data, adapter->assembled_data, toreuse);
668 /* copy the remaining data */
669 copy_into_unchecked (adapter, toreuse + data, toreuse + adapter->skip,
677 * @adapter: a #GstAdapter
678 * @nbytes: the number of bytes to take
680 * Returns a freshly allocated buffer containing the first @nbytes bytes of the
681 * @adapter. The returned bytes will be flushed from the adapter.
683 * Caller owns returned value. g_free after usage.
685 * Free-function: g_free
687 * Returns: (transfer full) (array length=nbytes) (element-type guint8):
688 * oven-fresh hot data, or #NULL if @nbytes bytes are not available
691 gst_adapter_take (GstAdapter * adapter, gsize nbytes)
695 g_return_val_if_fail (GST_IS_ADAPTER (adapter), NULL);
696 g_return_val_if_fail (nbytes > 0, NULL);
698 /* we don't have enough data, return NULL. This is unlikely
699 * as one usually does an _available() first instead of peeking a
701 if (G_UNLIKELY (nbytes > adapter->size))
704 data = gst_adapter_take_internal (adapter, nbytes);
706 gst_adapter_flush_unchecked (adapter, nbytes);
712 * gst_adapter_take_buffer_fast:
713 * @adapter: a #GstAdapter
714 * @nbytes: the number of bytes to take
716 * Returns a #GstBuffer containing the first @nbytes of the @adapter.
717 * The returned bytes will be flushed from the adapter. This function
718 * is potentially more performant than gst_adapter_take_buffer() since
719 * it can reuse the memory in pushed buffers by subbuffering or
720 * merging. Unlike gst_adapter_take_buffer(), the returned buffer may
721 * be composed of multiple non-contiguous #GstMemory objects, no
724 * Note that no assumptions should be made as to whether certain buffer
725 * flags such as the DISCONT flag are set on the returned buffer, or not.
726 * The caller needs to explicitly set or unset flags that should be set or
729 * This function can return buffer up to the return value of
730 * gst_adapter_available() without making copies if possible.
732 * Caller owns a reference to the returned buffer. gst_buffer_unref() after
735 * Free-function: gst_buffer_unref
737 * Returns: (transfer full): a #GstBuffer containing the first @nbytes of
738 * the adapter, or #NULL if @nbytes bytes are not available.
739 * gst_buffer_unref() when no longer needed.
745 gst_adapter_take_buffer_fast (GstAdapter * adapter, gsize nbytes)
747 GstBuffer *buffer = NULL;
753 g_return_val_if_fail (GST_IS_ADAPTER (adapter), NULL);
754 g_return_val_if_fail (nbytes > 0, NULL);
756 GST_LOG_OBJECT (adapter, "taking buffer of %" G_GSIZE_FORMAT " bytes",
759 /* we don't have enough data, return NULL. This is unlikely
760 * as one usually does an _available() first instead of grabbing a
762 if (G_UNLIKELY (nbytes > adapter->size))
765 skip = adapter->skip;
766 cur = adapter->buflist->data;
768 if (skip == 0 && gst_buffer_get_size (cur) == nbytes) {
769 GST_LOG_OBJECT (adapter, "providing buffer of %" G_GSIZE_FORMAT " bytes"
770 " as head buffer", nbytes);
771 buffer = gst_buffer_ref (cur);
775 for (item = adapter->buflist; item && left > 0; item = item->next) {
779 size = MIN (gst_buffer_get_size (cur) - skip, left);
781 GST_LOG_OBJECT (adapter, "appending %" G_GSIZE_FORMAT " bytes"
782 " via region copy", size);
784 gst_buffer_copy_into (buffer, cur, GST_BUFFER_COPY_MEMORY, skip, size);
786 buffer = gst_buffer_copy_region (cur, GST_BUFFER_COPY_ALL, skip, size);
792 gst_adapter_flush_unchecked (adapter, nbytes);
798 * gst_adapter_take_buffer:
799 * @adapter: a #GstAdapter
800 * @nbytes: the number of bytes to take
802 * Returns a #GstBuffer containing the first @nbytes bytes of the
803 * @adapter. The returned bytes will be flushed from the adapter.
804 * This function is potentially more performant than
805 * gst_adapter_take() since it can reuse the memory in pushed buffers
806 * by subbuffering or merging. This function will always return a
807 * buffer with a single memory region.
809 * Note that no assumptions should be made as to whether certain buffer
810 * flags such as the DISCONT flag are set on the returned buffer, or not.
811 * The caller needs to explicitly set or unset flags that should be set or
814 * Caller owns a reference to the returned buffer. gst_buffer_unref() after
817 * Free-function: gst_buffer_unref
819 * Returns: (transfer full): a #GstBuffer containing the first @nbytes of
820 * the adapter, or #NULL if @nbytes bytes are not available.
821 * gst_buffer_unref() when no longer needed.
824 gst_adapter_take_buffer (GstAdapter * adapter, gsize nbytes)
831 g_return_val_if_fail (GST_IS_ADAPTER (adapter), NULL);
832 g_return_val_if_fail (nbytes > 0, NULL);
834 GST_LOG_OBJECT (adapter, "taking buffer of %" G_GSIZE_FORMAT " bytes",
837 /* we don't have enough data, return NULL. This is unlikely
838 * as one usually does an _available() first instead of grabbing a
840 if (G_UNLIKELY (nbytes > adapter->size))
843 cur = adapter->buflist->data;
844 skip = adapter->skip;
845 hsize = gst_buffer_get_size (cur);
847 /* our head buffer has enough data left, return it */
848 if (skip == 0 && hsize == nbytes) {
849 GST_LOG_OBJECT (adapter, "providing buffer of %" G_GSIZE_FORMAT " bytes"
850 " as head buffer", nbytes);
851 buffer = gst_buffer_ref (cur);
853 } else if (hsize >= nbytes + skip) {
854 GST_LOG_OBJECT (adapter, "providing buffer of %" G_GSIZE_FORMAT " bytes"
855 " via region copy", nbytes);
856 buffer = gst_buffer_copy_region (cur, GST_BUFFER_COPY_ALL, skip, nbytes);
860 if (gst_adapter_try_to_merge_up (adapter, nbytes)) {
861 /* Merged something, let's try again for sub-buffering */
862 cur = adapter->buflist->data;
863 skip = adapter->skip;
864 if (gst_buffer_get_size (cur) >= nbytes + skip) {
865 GST_LOG_OBJECT (adapter, "providing buffer of %" G_GSIZE_FORMAT " bytes"
866 " via sub-buffer", nbytes);
867 buffer = gst_buffer_copy_region (cur, GST_BUFFER_COPY_ALL, skip, nbytes);
873 data = gst_adapter_take_internal (adapter, nbytes);
875 buffer = gst_buffer_new_wrapped (data, nbytes);
878 gst_adapter_flush_unchecked (adapter, nbytes);
884 * gst_adapter_take_list:
885 * @adapter: a #GstAdapter
886 * @nbytes: the number of bytes to take
888 * Returns a #GList of buffers containing the first @nbytes bytes of the
889 * @adapter. The returned bytes will be flushed from the adapter.
890 * When the caller can deal with individual buffers, this function is more
891 * performant because no memory should be copied.
893 * Caller owns returned list and contained buffers. gst_buffer_unref() each
894 * buffer in the list before freeing the list after usage.
896 * Returns: (element-type Gst.Buffer) (transfer full): a #GList of buffers
897 * containing the first @nbytes of the adapter, or #NULL if @nbytes bytes
901 gst_adapter_take_list (GstAdapter * adapter, gsize nbytes)
903 GQueue queue = G_QUEUE_INIT;
907 g_return_val_if_fail (GST_IS_ADAPTER (adapter), NULL);
908 g_return_val_if_fail (nbytes <= adapter->size, NULL);
910 GST_LOG_OBJECT (adapter, "taking %" G_GSIZE_FORMAT " bytes", nbytes);
913 cur = adapter->buflist->data;
914 skip = adapter->skip;
915 hsize = MIN (nbytes, gst_buffer_get_size (cur) - skip);
917 cur = gst_adapter_take_buffer (adapter, hsize);
919 g_queue_push_tail (&queue, cur);
927 * gst_adapter_available:
928 * @adapter: a #GstAdapter
930 * Gets the maximum amount of bytes available, that is it returns the maximum
931 * value that can be supplied to gst_adapter_map() without that function
934 * Returns: number of bytes available in @adapter
937 gst_adapter_available (GstAdapter * adapter)
939 g_return_val_if_fail (GST_IS_ADAPTER (adapter), 0);
941 return adapter->size;
945 * gst_adapter_available_fast:
946 * @adapter: a #GstAdapter
948 * Gets the maximum number of bytes that are immediately available without
949 * requiring any expensive operations (like copying the data into a
952 * Returns: number of bytes that are available in @adapter without expensive
956 gst_adapter_available_fast (GstAdapter * adapter)
962 g_return_val_if_fail (GST_IS_ADAPTER (adapter), 0);
965 if (adapter->size == 0)
968 /* some stuff we already assembled */
969 if (adapter->assembled_len)
970 return adapter->assembled_len;
972 /* take the first non-zero buffer */
973 g = adapter->buflist;
976 size = gst_buffer_get_size (cur);
979 g = g_slist_next (g);
982 /* we can quickly get the (remaining) data of the first buffer */
983 return size - adapter->skip;
987 * gst_adapter_prev_pts:
988 * @adapter: a #GstAdapter
989 * @distance: (out) (allow-none): pointer to location for distance, or NULL
991 * Get the pts that was before the current byte in the adapter. When
992 * @distance is given, the amount of bytes between the pts and the current
993 * position is returned.
995 * The pts is reset to GST_CLOCK_TIME_NONE and the distance is set to 0 when
996 * the adapter is first created or when it is cleared. This also means that before
997 * the first byte with a pts is removed from the adapter, the pts
998 * and distance returned are GST_CLOCK_TIME_NONE and 0 respectively.
1000 * Returns: The previously seen pts.
1003 gst_adapter_prev_pts (GstAdapter * adapter, guint64 * distance)
1005 g_return_val_if_fail (GST_IS_ADAPTER (adapter), GST_CLOCK_TIME_NONE);
1008 *distance = adapter->pts_distance;
1010 return adapter->pts;
1014 * gst_adapter_prev_dts:
1015 * @adapter: a #GstAdapter
1016 * @distance: (out) (allow-none): pointer to location for distance, or NULL
1018 * Get the dts that was before the current byte in the adapter. When
1019 * @distance is given, the amount of bytes between the dts and the current
1020 * position is returned.
1022 * The dts is reset to GST_CLOCK_TIME_NONE and the distance is set to 0 when
1023 * the adapter is first created or when it is cleared. This also means that before
1024 * the first byte with a dts is removed from the adapter, the dts
1025 * and distance returned are GST_CLOCK_TIME_NONE and 0 respectively.
1027 * Returns: The previously seen dts.
1030 gst_adapter_prev_dts (GstAdapter * adapter, guint64 * distance)
1032 g_return_val_if_fail (GST_IS_ADAPTER (adapter), GST_CLOCK_TIME_NONE);
1035 *distance = adapter->dts_distance;
1037 return adapter->dts;
1041 * gst_adapter_prev_pts_at_offset:
1042 * @adapter: a #GstAdapter
1043 * @offset: the offset in the adapter at which to get timestamp
1044 * @distance: (out) (allow-none): pointer to location for distance, or NULL
1046 * Get the pts that was before the byte at offset @offset in the adapter. When
1047 * @distance is given, the amount of bytes between the pts and the current
1048 * position is returned.
1050 * The pts is reset to GST_CLOCK_TIME_NONE and the distance is set to 0 when
1051 * the adapter is first created or when it is cleared. This also means that before
1052 * the first byte with a pts is removed from the adapter, the pts
1053 * and distance returned are GST_CLOCK_TIME_NONE and 0 respectively.
1056 * Returns: The previously seen pts at given offset.
1059 gst_adapter_prev_pts_at_offset (GstAdapter * adapter, gsize offset,
1064 gsize read_offset = 0;
1065 GstClockTime pts = adapter->pts;
1067 g_return_val_if_fail (GST_IS_ADAPTER (adapter), GST_CLOCK_TIME_NONE);
1068 g_return_val_if_fail (offset >= 0, GST_CLOCK_TIME_NONE);
1070 g = adapter->buflist;
1072 while (g && read_offset < offset + adapter->skip) {
1075 read_offset += gst_buffer_get_size (cur);
1076 if (GST_CLOCK_TIME_IS_VALID (GST_BUFFER_PTS (cur))) {
1077 pts = GST_BUFFER_PTS (cur);
1080 g = g_slist_next (g);
1084 *distance = adapter->dts_distance + offset;
1090 * gst_adapter_prev_dts_at_offset:
1091 * @adapter: a #GstAdapter
1092 * @offset: the offset in the adapter at which to get timestamp
1093 * @distance: (out) (allow-none): pointer to location for distance, or NULL
1095 * Get the dts that was before the byte at offset @offset in the adapter. When
1096 * @distance is given, the amount of bytes between the dts and the current
1097 * position is returned.
1099 * The dts is reset to GST_CLOCK_TIME_NONE and the distance is set to 0 when
1100 * the adapter is first created or when it is cleared. This also means that before
1101 * the first byte with a dts is removed from the adapter, the dts
1102 * and distance returned are GST_CLOCK_TIME_NONE and 0 respectively.
1105 * Returns: The previously seen dts at given offset.
1108 gst_adapter_prev_dts_at_offset (GstAdapter * adapter, gsize offset,
1113 gsize read_offset = 0;
1114 GstClockTime dts = adapter->dts;
1116 g_return_val_if_fail (GST_IS_ADAPTER (adapter), GST_CLOCK_TIME_NONE);
1117 g_return_val_if_fail (offset >= 0, GST_CLOCK_TIME_NONE);
1119 g = adapter->buflist;
1121 while (g && read_offset < offset + adapter->skip) {
1124 read_offset += gst_buffer_get_size (cur);
1125 if (GST_CLOCK_TIME_IS_VALID (GST_BUFFER_DTS (cur))) {
1126 dts = GST_BUFFER_DTS (cur);
1129 g = g_slist_next (g);
1133 *distance = adapter->dts_distance + offset;
1139 * gst_adapter_masked_scan_uint32_peek:
1140 * @adapter: a #GstAdapter
1141 * @mask: mask to apply to data before matching against @pattern
1142 * @pattern: pattern to match (after mask is applied)
1143 * @offset: offset into the adapter data from which to start scanning, returns
1144 * the last scanned position.
1145 * @size: number of bytes to scan from offset
1146 * @value: pointer to uint32 to return matching data
1148 * Scan for pattern @pattern with applied mask @mask in the adapter data,
1149 * starting from offset @offset. If a match is found, the value that matched
1150 * is returned through @value, otherwise @value is left untouched.
1152 * The bytes in @pattern and @mask are interpreted left-to-right, regardless
1153 * of endianness. All four bytes of the pattern must be present in the
1154 * adapter for it to match, even if the first or last bytes are masked out.
1156 * It is an error to call this function without making sure that there is
1157 * enough data (offset+size bytes) in the adapter.
1159 * Returns: offset of the first match, or -1 if no match was found.
1162 gst_adapter_masked_scan_uint32_peek (GstAdapter * adapter, guint32 mask,
1163 guint32 pattern, gsize offset, gsize size, guint32 * value)
1166 gsize skip, bsize, i;
1172 g_return_val_if_fail (size > 0, -1);
1173 g_return_val_if_fail (offset + size <= adapter->size, -1);
1174 g_return_val_if_fail (((~mask) & pattern) == 0, -1);
1176 /* we can't find the pattern with less than 4 bytes */
1177 if (G_UNLIKELY (size < 4))
1180 skip = offset + adapter->skip;
1182 /* first step, do skipping and position on the first buffer */
1183 /* optimistically assume scanning continues sequentially */
1184 if (adapter->scan_entry && (adapter->scan_offset <= skip)) {
1185 g = adapter->scan_entry;
1186 skip -= adapter->scan_offset;
1188 g = adapter->buflist;
1189 adapter->scan_offset = 0;
1190 adapter->scan_entry = NULL;
1193 bsize = gst_buffer_get_size (buf);
1194 while (G_UNLIKELY (skip >= bsize)) {
1196 g = g_slist_next (g);
1197 adapter->scan_offset += bsize;
1198 adapter->scan_entry = g;
1200 bsize = gst_buffer_get_size (buf);
1202 /* get the data now */
1203 if (!gst_buffer_map (buf, &info, GST_MAP_READ))
1206 bdata = (guint8 *) info.data + skip;
1207 bsize = info.size - skip;
1210 /* set the state to something that does not match */
1215 bsize = MIN (bsize, size);
1216 for (i = 0; i < bsize; i++) {
1217 state = ((state << 8) | bdata[i]);
1218 if (G_UNLIKELY ((state & mask) == pattern)) {
1219 /* we have a match but we need to have skipped at
1220 * least 4 bytes to fill the state. */
1221 if (G_LIKELY (skip + i >= 3)) {
1222 if (G_LIKELY (value))
1224 gst_buffer_unmap (buf, &info);
1225 return offset + skip + i - 3;
1233 /* nothing found yet, go to next buffer */
1235 g = g_slist_next (g);
1236 adapter->scan_offset += info.size;
1237 adapter->scan_entry = g;
1238 gst_buffer_unmap (buf, &info);
1241 if (!gst_buffer_map (buf, &info, GST_MAP_READ))
1248 gst_buffer_unmap (buf, &info);
1255 * gst_adapter_masked_scan_uint32:
1256 * @adapter: a #GstAdapter
1257 * @mask: mask to apply to data before matching against @pattern
1258 * @pattern: pattern to match (after mask is applied)
1259 * @offset: offset into the adapter data from which to start scanning, returns
1260 * the last scanned position.
1261 * @size: number of bytes to scan from offset
1263 * Scan for pattern @pattern with applied mask @mask in the adapter data,
1264 * starting from offset @offset.
1266 * The bytes in @pattern and @mask are interpreted left-to-right, regardless
1267 * of endianness. All four bytes of the pattern must be present in the
1268 * adapter for it to match, even if the first or last bytes are masked out.
1270 * It is an error to call this function without making sure that there is
1271 * enough data (offset+size bytes) in the adapter.
1273 * This function calls gst_adapter_masked_scan_uint32_peek() passing NULL
1276 * Returns: offset of the first match, or -1 if no match was found.
1280 * // Assume the adapter contains 0x00 0x01 0x02 ... 0xfe 0xff
1282 * gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x00010203, 0, 256);
1284 * gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x00010203, 1, 255);
1286 * gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x01020304, 1, 255);
1288 * gst_adapter_masked_scan_uint32 (adapter, 0xffff, 0x0001, 0, 256);
1290 * gst_adapter_masked_scan_uint32 (adapter, 0xffff, 0x0203, 0, 256);
1292 * gst_adapter_masked_scan_uint32 (adapter, 0xffff0000, 0x02030000, 0, 256);
1294 * gst_adapter_masked_scan_uint32 (adapter, 0xffff0000, 0x02030000, 0, 4);
1299 gst_adapter_masked_scan_uint32 (GstAdapter * adapter, guint32 mask,
1300 guint32 pattern, gsize offset, gsize size)
1302 return gst_adapter_masked_scan_uint32_peek (adapter, mask, pattern, offset,