125a9e5561a7f14e79b04f713a515a9464b9ea077Steven Moreland/*
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    // On entry:
44    //  buffer              != NULL
45    //  buffer->raw         unused
46    //  buffer->frameCount  maximum number of desired frames
47    // On successful return:
48    //  status              NO_ERROR
49    //  buffer->raw         non-NULL pointer to buffer->frameCount contiguous available frames
50    //  buffer->frameCount  number of contiguous available frames at buffer->raw,
51    //                      0 < buffer->frameCount <= entry value
52    // On error return:
53    //  status              != NO_ERROR
54    //  buffer->raw         NULL
55    //  buffer->frameCount  0
56    virtual status_t getNextBuffer(Buffer* buffer) = 0;
57
58    // Release (a portion of) the buffer previously obtained by getNextBuffer().
59    // It is permissible to call releaseBuffer() multiple times per getNextBuffer().
60    // On entry:
61    //  buffer->frameCount  number of frames to release, must be <= number of frames
62    //                      obtained but not yet released
63    //  buffer->raw         unused
64    // On return:
65    //  buffer->frameCount  0; implementation MUST set to zero
66    //  buffer->raw         undefined; implementation is PERMITTED to set to any value,
67    //                      so if caller needs to continue using this buffer it must
68    //                      keep track of the pointer itself
69    virtual void releaseBuffer(Buffer* buffer) = 0;
70};
71
72// ----------------------------------------------------------------------------
73}; // namespace android
74
75#endif // ANDROID_AUDIO_BUFFER_PROVIDER_H
76