AudioStreamOut.h revision 90eea7631b07117e46ae8b84889a2baa3eee7aea
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 virtual size_t getFrameSize(); 79 80 virtual status_t flush(); 81 virtual status_t standby(); 82 83protected: 84 uint64_t mFramesWritten; // reset by flush 85 uint64_t mFramesWrittenAtStandby; 86 uint64_t mRenderPosition; // reset by flush or standby 87 int mRateMultiplier; 88 bool mHalFormatIsLinearPcm; 89 size_t mHalFrameSize; 90}; 91 92} // namespace android 93 94#endif // ANDROID_AUDIO_STREAM_OUT_H 95