AudioBufferProvider.h revision 9f80dd223d83d9bb9077fb6baee056cee4eaf7e5 
1/*
2 * Copyright (C) 2007 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 ANDROID_AUDIO_BUFFER_PROVIDER_H
18#define ANDROID_AUDIO_BUFFER_PROVIDER_H
19
20#include <utils/Errors.h>
21
22namespace android {
23// ----------------------------------------------------------------------------
24
25class AudioBufferProvider
26{
27public:
28
29    // FIXME merge with AudioTrackShared::Buffer, AudioTrack::Buffer, and AudioRecord::Buffer
30    //       and rename getNextBuffer() to obtainBuffer()
31    struct Buffer {
32        Buffer() : raw(NULL), frameCount(0) { }
33        union {
34            void*       raw;
35            short*      i16;
36            int8_t*     i8;
37        };
38        size_t frameCount;
39    };
40
41    virtual ~AudioBufferProvider() {}
42
43    // value representing an invalid presentation timestamp
44    static const int64_t kInvalidPTS = 0x7FFFFFFFFFFFFFFFLL;    // <stdint.h> is too painful
45
46    // pts is the local time when the next sample yielded by getNextBuffer
47    // will be rendered.
48    // Pass kInvalidPTS if the PTS is unknown or not applicable.
49    // On entry:
50    //  buffer              != NULL
51    //  buffer->raw         unused
52    //  buffer->frameCount  maximum number of desired frames
53    // On successful return:
54    //  status              NO_ERROR
55    //  buffer->raw         non-NULL pointer to buffer->frameCount contiguous available frames
56    //  buffer->frameCount  number of contiguous available frames at buffer->raw,
57    //                      0 < buffer->frameCount <= entry value
58    // On error return:
59    //  status              != NO_ERROR
60    //  buffer->raw         NULL
61    //  buffer->frameCount  0
62    virtual status_t getNextBuffer(Buffer* buffer, int64_t pts = kInvalidPTS) = 0;
63
64    virtual void releaseBuffer(Buffer* buffer) = 0;
65};
66
67// ----------------------------------------------------------------------------
68}; // namespace android
69
70#endif // ANDROID_AUDIO_BUFFER_PROVIDER_H
71