BufferQueueSource.h revision 70e6a0238597223221a8bf5e506c92acf28aa35f 
1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef BUFFERQUEUE_SOURCE_H_
18#define BUFFERQUEUE_SOURCE_H_
19
20#include <media/stagefright/DataSource.h>
21
22// number of SLuint32 fields to store a buffer event message in an item, by mapping each
23//   to the item key (SLuint32), the item size (SLuint32), and the item data (mask on SLuint32)
24#define NB_BUFFEREVENT_ITEM_FIELDS 3
25
26namespace android {
27
28// a Stagefright DataSource that pulls data from an AndroidBufferQueue
29
30class BufferQueueSource : public DataSource {
31public:
32
33    // store an item structure to indicate a processed buffer
34    static const SLuint32 kItemProcessed[NB_BUFFEREVENT_ITEM_FIELDS];
35
36    BufferQueueSource(IAndroidBufferQueue *androidBufferQueue);
37
38    virtual status_t initCheck() const;
39
40    virtual ssize_t readAt(off64_t offset, void *data, size_t size);
41
42    virtual status_t getSize(off64_t *size);
43
44    virtual ~BufferQueueSource();
45
46private:
47    // the Android Buffer Queue from which data is consumed
48    IAndroidBufferQueue* const mAndroidBufferQueueSource;
49
50    // a monotonically increasing offset used to translate an offset from the beginning
51    // of the stream, to an offset in each buffer from the buffer queue source
52    off64_t mStreamToBqOffset;
53
54    // indicates whether an EOS command has been reached when consuming the buffers in the queue
55    bool mEosReached;
56
57    BufferQueueSource(const BufferQueueSource &);
58    BufferQueueSource &operator=(const BufferQueueSource &);
59};
60
61}  // namespace android
62
63#endif  // BUFFERQUEUE_SOURCE_H_
64
65