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 "gstatomic_impl.h"
26 #include "gstdata_private.h"
27 #include "gstbuffer.h"
28 #include "gstmemchunk.h"
31 GType _gst_buffer_type;
33 #ifndef GST_DISABLE_TRACE
34 /* #define GST_WITH_ALLOC_TRACE */
37 static GstAllocTrace *_gst_buffer_trace;
40 static GstMemChunk *chunk;
42 static GstBuffer *gst_buffer_alloc_chunk (void);
43 static void gst_buffer_free_chunk (GstBuffer * buffer);
46 _gst_buffer_initialize (void)
48 _gst_buffer_type = g_boxed_type_register_static ("GstBuffer",
49 (GBoxedCopyFunc) gst_data_copy, (GBoxedFreeFunc) gst_data_unref);
51 #ifndef GST_DISABLE_TRACE
52 _gst_buffer_trace = gst_alloc_trace_register (GST_BUFFER_TRACE_NAME);
55 chunk = gst_mem_chunk_new ("GstBufferChunk", sizeof (GstBuffer),
56 sizeof (GstBuffer) * 200, 0);
58 GST_CAT_LOG (GST_CAT_BUFFER, "Buffers are initialized now");
62 gst_buffer_get_type (void)
64 return _gst_buffer_type;
68 _gst_buffer_sub_free (GstBuffer * buffer)
70 gst_data_unref (GST_DATA (buffer->buffer_private));
72 GST_BUFFER_DATA (buffer) = NULL;
73 GST_BUFFER_SIZE (buffer) = 0;
75 _GST_DATA_DISPOSE (GST_DATA (buffer));
77 gst_buffer_free_chunk (buffer);
81 * gst_buffer_default_free:
82 * @buffer: a #GstBuffer to free.
84 * Frees the memory associated with the buffer including the buffer data,
85 * unless the GST_BUFFER_DONTFREE flags was set or the buffer data is NULL.
88 gst_buffer_default_free (GstBuffer * buffer)
90 g_return_if_fail (buffer != NULL);
93 if (GST_BUFFER_FREE_DATA_FUNC (buffer)) {
94 GST_BUFFER_FREE_DATA_FUNC (buffer) (buffer);
95 } else if (!GST_BUFFER_FLAG_IS_SET (buffer, GST_BUFFER_DONTFREE)) {
96 g_free (GST_BUFFER_DATA (buffer));
99 /* set to safe values */
100 GST_BUFFER_DATA (buffer) = NULL;
101 GST_BUFFER_SIZE (buffer) = 0;
103 _GST_DATA_DISPOSE (GST_DATA (buffer));
105 gst_buffer_free_chunk (buffer);
110 * @dest: buffer to stamp
111 * @src: buffer to stamp from
113 * Copies additional information (timestamps and offsets) from one buffer to
117 gst_buffer_stamp (GstBuffer * dest, const GstBuffer * src)
119 g_return_if_fail (dest != NULL);
120 g_return_if_fail (src != NULL);
122 GST_BUFFER_TIMESTAMP (dest) = GST_BUFFER_TIMESTAMP (src);
123 GST_BUFFER_DURATION (dest) = GST_BUFFER_DURATION (src);
124 GST_BUFFER_OFFSET (dest) = GST_BUFFER_OFFSET (src);
125 GST_BUFFER_OFFSET_END (dest) = GST_BUFFER_OFFSET_END (src);
129 * gst_buffer_default_copy:
130 * @buffer: a #GstBuffer to make a copy of.
132 * Make a full newly allocated copy of the given buffer, data and all.
134 * Returns: the new #GstBuffer.
137 gst_buffer_default_copy (GstBuffer * buffer)
141 g_return_val_if_fail (buffer != NULL, NULL);
143 /* create a fresh new buffer */
144 copy = gst_buffer_alloc_chunk ();
146 _GST_DATA_INIT (GST_DATA (copy),
149 (GstDataFreeFunction) gst_buffer_default_free,
150 (GstDataCopyFunction) gst_buffer_default_copy);
152 /* we simply copy everything from our parent */
153 GST_BUFFER_DATA (copy) = g_memdup (GST_BUFFER_DATA (buffer),
154 GST_BUFFER_SIZE (buffer));
155 GST_BUFFER_SIZE (copy) = GST_BUFFER_SIZE (buffer);
156 GST_BUFFER_MAXSIZE (copy) = GST_BUFFER_SIZE (buffer);
158 gst_buffer_stamp (copy, buffer);
159 GST_BUFFER_FREE_DATA_FUNC (copy) = NULL;
160 GST_BUFFER_PRIVATE (copy) = NULL;
166 gst_buffer_alloc_chunk (void)
170 newbuf = gst_mem_chunk_alloc (chunk);
171 #ifndef GST_DISABLE_TRACE
172 gst_alloc_trace_new (_gst_buffer_trace, newbuf);
179 gst_buffer_free_chunk (GstBuffer * buffer)
181 gst_mem_chunk_free (chunk, GST_DATA (buffer));
182 #ifndef GST_DISABLE_TRACE
183 gst_alloc_trace_free (_gst_buffer_trace, buffer);
190 * Creates a newly allocated buffer without any data.
192 * Returns: the new #GstBuffer.
195 gst_buffer_new (void)
199 newbuf = gst_buffer_alloc_chunk ();
201 GST_CAT_LOG (GST_CAT_BUFFER, "new %p", newbuf);
203 _GST_DATA_INIT (GST_DATA (newbuf),
206 (GstDataFreeFunction) gst_buffer_default_free,
207 (GstDataCopyFunction) gst_buffer_default_copy);
209 GST_BUFFER_DATA (newbuf) = NULL;
210 GST_BUFFER_SIZE (newbuf) = 0;
211 GST_BUFFER_MAXSIZE (newbuf) = GST_BUFFER_MAXSIZE_NONE;
212 GST_BUFFER_TIMESTAMP (newbuf) = GST_CLOCK_TIME_NONE;
213 GST_BUFFER_DURATION (newbuf) = GST_CLOCK_TIME_NONE;
214 GST_BUFFER_OFFSET (newbuf) = GST_BUFFER_OFFSET_NONE;
215 GST_BUFFER_OFFSET_END (newbuf) = GST_BUFFER_OFFSET_NONE;
216 GST_BUFFER_FREE_DATA_FUNC (newbuf) = NULL;
217 GST_BUFFER_PRIVATE (newbuf) = NULL;
223 * gst_buffer_new_and_alloc:
224 * @size: the size of the new buffer's data.
226 * Creates a newly allocated buffer with data of the given size.
228 * Returns: the new #GstBuffer.
231 gst_buffer_new_and_alloc (guint size)
235 newbuf = gst_buffer_new ();
237 GST_BUFFER_DATA (newbuf) = g_malloc (size);
238 GST_BUFFER_SIZE (newbuf) = size;
239 GST_BUFFER_MAXSIZE (newbuf) = size;
245 * gst_buffer_create_sub:
246 * @parent: a parent #GstBuffer to create a subbuffer from.
247 * @offset: the offset into parent #GstBuffer.
248 * @size: the size of the new #GstBuffer sub-buffer (with size > 0).
250 * Creates a sub-buffer from the parent at a given offset.
251 * This sub-buffer uses the actual memory space of the parent buffer.
252 * This function will copy the offset and timestamp field when the
253 * offset is 0, else they are set to _NONE.
254 * The duration field of the new buffer are set to GST_CLOCK_TIME_NONE.
256 * Returns: the new #GstBuffer, or NULL if there was an error.
259 gst_buffer_create_sub (GstBuffer * parent, guint offset, guint size)
262 gpointer buffer_data;
264 g_return_val_if_fail (parent != NULL, NULL);
265 g_return_val_if_fail (GST_BUFFER_REFCOUNT_VALUE (parent) > 0, NULL);
266 g_return_val_if_fail (size > 0, NULL);
267 g_return_val_if_fail (parent->size >= offset + size, NULL);
269 /* remember the data for the new buffer */
270 buffer_data = parent->data + offset;
271 /* make sure we're child not child from a child buffer */
272 while (GST_BUFFER_FLAG_IS_SET (parent, GST_BUFFER_SUBBUFFER)) {
273 parent = GST_BUFFER (parent->buffer_private);
275 /* ref the real parent */
276 gst_data_ref (GST_DATA (parent));
278 /* create the new buffer */
279 buffer = gst_buffer_alloc_chunk ();
281 GST_CAT_LOG (GST_CAT_BUFFER, "new subbuffer %p (parent %p)", buffer, parent);
283 /* make sure nobody overwrites data in the new buffer
284 * by setting the READONLY flag */
285 _GST_DATA_INIT (GST_DATA (buffer),
287 GST_DATA_FLAG_SHIFT (GST_BUFFER_SUBBUFFER) |
288 GST_DATA_FLAG_SHIFT (GST_DATA_READONLY),
289 (GstDataFreeFunction) _gst_buffer_sub_free,
290 (GstDataCopyFunction) gst_buffer_default_copy);
292 /* set the right values in the child */
293 GST_BUFFER_DATA (buffer) = buffer_data;
294 GST_BUFFER_SIZE (buffer) = size;
295 GST_BUFFER_MAXSIZE (buffer) = size;
296 GST_BUFFER_FREE_DATA_FUNC (buffer) = NULL;
297 GST_BUFFER_PRIVATE (buffer) = parent;
298 /* we can copy the timestamp and offset if the new buffer starts at
301 GST_BUFFER_TIMESTAMP (buffer) = GST_BUFFER_TIMESTAMP (parent);
302 GST_BUFFER_OFFSET (buffer) = GST_BUFFER_OFFSET (parent);
304 GST_BUFFER_TIMESTAMP (buffer) = GST_CLOCK_TIME_NONE;
305 GST_BUFFER_OFFSET (buffer) = GST_BUFFER_OFFSET_NONE;
308 GST_BUFFER_DURATION (buffer) = GST_CLOCK_TIME_NONE;
309 GST_BUFFER_OFFSET_END (buffer) = GST_BUFFER_OFFSET_NONE;
311 if (GST_BUFFER_FLAG_IS_SET (parent, GST_BUFFER_DONTKEEP)) {
312 GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_DONTKEEP);
314 if (GST_BUFFER_FLAG_IS_SET (parent, GST_BUFFER_READONLY)) {
315 GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_READONLY);
324 * @buf1: a first source #GstBuffer to merge.
325 * @buf2: the second source #GstBuffer to merge.
327 * Create a new buffer that is the concatenation of the two source
328 * buffers. The original source buffers will not be modified or
331 * WARNING: Incorrect use of this function can lead to memory leaks.
332 * It is recommended to use gst_buffer_join() instead of this function.
334 * If the buffers point to contiguous areas of memory, the buffer
335 * is created without copying the data.
337 * Returns: the new #GstBuffer that's the concatenation of the source buffers.
340 gst_buffer_merge (GstBuffer * buf1, GstBuffer * buf2)
344 /* we're just a specific case of the more general gst_buffer_span() */
345 result = gst_buffer_span (buf1, 0, buf2, buf1->size + buf2->size);
352 * @buf1: a first source #GstBuffer to merge.
353 * @buf2: the second source #GstBuffer to merge.
355 * Create a new buffer that is the concatenation of the two source
356 * buffers. The original buffers are unreferenced.
358 * If the buffers point to contiguous areas of memory, the buffer
359 * is created without copying the data.
361 * Returns: the new #GstBuffer that's the concatenation of the source buffers.
364 gst_buffer_join (GstBuffer * buf1, GstBuffer * buf2)
368 /* we're just a specific case of the more general gst_buffer_span() */
369 result = gst_buffer_span (buf1, 0, buf2, buf1->size + buf2->size);
371 gst_buffer_unref (buf1);
372 gst_buffer_unref (buf2);
378 * gst_buffer_is_span_fast:
379 * @buf1: a first source #GstBuffer.
380 * @buf2: the second source #GstBuffer.
382 * Determines whether a gst_buffer_span() can be done without copying
383 * the contents, that is, whether the data areas are contiguous.
385 * Returns: TRUE if the buffers are contiguous,
386 * FALSE if a copy would be required.
389 gst_buffer_is_span_fast (GstBuffer * buf1, GstBuffer * buf2)
391 g_return_val_if_fail (buf1 != NULL && buf2 != NULL, FALSE);
392 g_return_val_if_fail (GST_BUFFER_REFCOUNT_VALUE (buf1) > 0, FALSE);
393 g_return_val_if_fail (GST_BUFFER_REFCOUNT_VALUE (buf2) > 0, FALSE);
395 /* it's only fast if we have subbuffers of the same parent */
396 return ((GST_BUFFER_FLAG_IS_SET (buf1, GST_BUFFER_SUBBUFFER)) &&
397 (GST_BUFFER_FLAG_IS_SET (buf2, GST_BUFFER_SUBBUFFER)) &&
398 (buf1->buffer_private == buf2->buffer_private) &&
399 ((buf1->data + buf1->size) == buf2->data));
404 * @buf1: a first source #GstBuffer to merge.
405 * @offset: the offset in the first buffer from where the new
406 * buffer should start.
407 * @buf2: the second source #GstBuffer to merge.
408 * @len: the total length of the new buffer.
410 * Creates a new buffer that consists of part of buf1 and buf2.
411 * Logically, buf1 and buf2 are concatenated into a single larger
412 * buffer, and a new buffer is created at the given offset inside
413 * this space, with a given length.
415 * If the two source buffers are children of the same larger buffer,
416 * and are contiguous, the new buffer will be a child of the shared
417 * parent, and thus no copying is necessary. you can use
418 * gst_buffer_is_span_fast() to determine if a memcpy will be needed.
420 * Returns: the new #GstBuffer that spans the two source buffers.
423 gst_buffer_span (GstBuffer * buf1, guint32 offset, GstBuffer * buf2,
428 g_return_val_if_fail (buf1 != NULL && buf2 != NULL, FALSE);
429 g_return_val_if_fail (GST_BUFFER_REFCOUNT_VALUE (buf1) > 0, NULL);
430 g_return_val_if_fail (GST_BUFFER_REFCOUNT_VALUE (buf2) > 0, NULL);
431 g_return_val_if_fail (len > 0, NULL);
432 g_return_val_if_fail (len <= buf1->size + buf2->size - offset, NULL);
434 /* if the two buffers have the same parent and are adjacent */
435 if (gst_buffer_is_span_fast (buf1, buf2)) {
436 GstBuffer *parent = GST_BUFFER (buf1->buffer_private);
438 /* we simply create a subbuffer of the common parent */
439 newbuf = gst_buffer_create_sub (parent,
440 buf1->data - parent->data + offset, len);
442 GST_CAT_DEBUG (GST_CAT_BUFFER,
443 "slow path taken while spanning buffers %p and %p", buf1, buf2);
444 /* otherwise we simply have to brute-force copy the buffers */
445 newbuf = gst_buffer_new_and_alloc (len);
447 /* copy the first buffer's data across */
448 memcpy (newbuf->data, buf1->data + offset, buf1->size - offset);
449 /* copy the second buffer's data across */
450 memcpy (newbuf->data + (buf1->size - offset), buf2->data,
451 len - (buf1->size - offset));
452 /* if the offset is 0, the new buffer has the same timestamp as buf1 */
454 GST_BUFFER_OFFSET (newbuf) = GST_BUFFER_OFFSET (buf1);
455 GST_BUFFER_TIMESTAMP (newbuf) = GST_BUFFER_TIMESTAMP (buf1);
458 /* if we completely merged the two buffers (appended), we can
459 * calculate the duration too. Also make sure we's not messing with
460 * invalid DURATIONS */
461 if (offset == 0 && buf1->size + buf2->size == len) {
462 if (GST_BUFFER_DURATION_IS_VALID (buf1) &&
463 GST_BUFFER_DURATION_IS_VALID (buf2)) {
465 GST_BUFFER_DURATION (newbuf) = GST_BUFFER_DURATION (buf1) +
466 GST_BUFFER_DURATION (buf2);
468 if (GST_BUFFER_OFFSET_END_IS_VALID (buf2)) {
470 GST_BUFFER_OFFSET_END (newbuf) = GST_BUFFER_OFFSET_END (buf2);