1/*
2**
3** Copyright 2015, The Android Open Source Project
4**
5** Licensed under the Apache License, Version 2.0 (the "License");
6** you may not use this file except in compliance with the License.
7** You may obtain a copy of the License at
8**
9**     http://www.apache.org/licenses/LICENSE-2.0
10**
11** Unless required by applicable law or agreed to in writing, software
12** distributed under the License is distributed on an "AS IS" BASIS,
13** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14** See the License for the specific language governing permissions and
15** limitations under the License.
16*/
17
18#ifndef ANDROID_AUDIO_STREAM_OUT_H
19#define ANDROID_AUDIO_STREAM_OUT_H
20
21#include <stdint.h>
22#include <sys/types.h>
23
24#include <system/audio.h>
25
26#include "AudioStreamOut.h"
27
28namespace android {
29
30class AudioHwDevice;
31
32/**
33 * Managed access to a HAL output stream.
34 */
35class AudioStreamOut {
36public:
37// AudioStreamOut is immutable, so its fields are const.
38// For emphasis, we could also make all pointers to them be "const *",
39// but that would clutter the code unnecessarily.
40    AudioHwDevice * const audioHwDev;
41    audio_stream_out_t *stream;
42    const audio_output_flags_t flags;
43
44    audio_hw_device_t *hwDev() const;
45
46    AudioStreamOut(AudioHwDevice *dev, audio_output_flags_t flags);
47
48    virtual status_t open(
49            audio_io_handle_t handle,
50            audio_devices_t devices,
51            struct audio_config *config,
52            const char *address);
53
54    virtual ~AudioStreamOut() { }
55
56    // Get the bottom 32-bits of the 64-bit render position.
57    status_t getRenderPosition(uint32_t *frames);
58
59    virtual status_t getRenderPosition(uint64_t *frames);
60
61    virtual status_t getPresentationPosition(uint64_t *frames, struct timespec *timestamp);
62
63    /**
64    * Write audio buffer to driver. Returns number of bytes written, or a
65    * negative status_t. If at least one frame was written successfully prior to the error,
66    * it is suggested that the driver return that successful (short) byte count
67    * and then return an error in the subsequent call.
68    *
69    * If set_callback() has previously been called to enable non-blocking mode
70    * the write() is not allowed to block. It must write only the number of
71    * bytes that currently fit in the driver/hardware buffer and then return
72    * this byte count. If this is less than the requested write size the
73    * callback function must be called when more space is available in the
74    * driver/hardware buffer.
75    */
76    virtual ssize_t write(const void *buffer, size_t bytes);
77
78    /**
79     * @return frame size from the perspective of the application and the AudioFlinger.
80     */
81    virtual size_t getFrameSize() const { return mHalFrameSize; }
82
83    /**
84     * @return format from the perspective of the application and the AudioFlinger.
85     */
86    virtual audio_format_t getFormat() const;
87
88    /**
89     * The HAL may be running at a higher sample rate if, for example, playing wrapped EAC3.
90     * @return sample rate from the perspective of the application and the AudioFlinger.
91     */
92    virtual uint32_t getSampleRate() const;
93
94    /**
95     * The HAL is in stereo mode when playing multi-channel compressed audio over HDMI.
96     * @return channel mask from the perspective of the application and the AudioFlinger.
97     */
98    virtual audio_channel_mask_t getChannelMask() const;
99
100
101    virtual status_t flush();
102    virtual status_t standby();
103
104protected:
105    uint64_t             mFramesWritten; // reset by flush
106    uint64_t             mFramesWrittenAtStandby;
107    uint64_t             mRenderPosition; // reset by flush or standby
108    int                  mRateMultiplier;
109    bool                 mHalFormatHasProportionalFrames;
110    size_t               mHalFrameSize;
111};
112
113} // namespace android
114
115#endif // ANDROID_AUDIO_STREAM_OUT_H
116