119 lines
4.2 KiB
C++
119 lines
4.2 KiB
C++
/*
|
|
* Copyright (C) 2016 The Android Open Source Project
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
#ifndef OBOE_STREAM_CALLBACK_H
|
|
#define OBOE_STREAM_CALLBACK_H
|
|
|
|
#include "oboe/Definitions.h"
|
|
|
|
namespace oboe {
|
|
|
|
class AudioStream;
|
|
|
|
/**
|
|
* AudioStreamCallback defines a callback interface for:
|
|
*
|
|
* 1) moving data to/from an audio stream using `onAudioReady`
|
|
* 2) being alerted when a stream has an error using `onError*` methods
|
|
*
|
|
*/
|
|
class AudioStreamCallback {
|
|
public:
|
|
virtual ~AudioStreamCallback() = default;
|
|
|
|
/**
|
|
* A buffer is ready for processing.
|
|
*
|
|
* For an output stream, this function should render and write numFrames of data
|
|
* in the stream's current data format to the audioData buffer.
|
|
*
|
|
* For an input stream, this function should read and process numFrames of data
|
|
* from the audioData buffer.
|
|
*
|
|
* The audio data is passed through the buffer. So do NOT call read() or
|
|
* write() on the stream that is making the callback.
|
|
*
|
|
* Note that numFrames can vary unless AudioStreamBuilder::setFramesPerCallback()
|
|
* is called.
|
|
*
|
|
* Also note that this callback function should be considered a "real-time" function.
|
|
* It must not do anything that could cause an unbounded delay because that can cause the
|
|
* audio to glitch or pop.
|
|
*
|
|
* These are things the function should NOT do:
|
|
* <ul>
|
|
* <li>allocate memory using, for example, malloc() or new</li>
|
|
* <li>any file operations such as opening, closing, reading or writing</li>
|
|
* <li>any network operations such as streaming</li>
|
|
* <li>use any mutexes or other synchronization primitives</li>
|
|
* <li>sleep</li>
|
|
* <li>oboeStream->stop(), pause(), flush() or close()</li>
|
|
* <li>oboeStream->read()</li>
|
|
* <li>oboeStream->write()</li>
|
|
* </ul>
|
|
*
|
|
* The following are OK to call from the data callback:
|
|
* <ul>
|
|
* <li>oboeStream->get*()</li>
|
|
* <li>oboe::convertToText()</li>
|
|
* <li>oboeStream->setBufferSizeInFrames()</li>
|
|
* </ul>
|
|
*
|
|
* If you need to move data, eg. MIDI commands, in or out of the callback function then
|
|
* we recommend the use of non-blocking techniques such as an atomic FIFO.
|
|
*
|
|
* @param oboeStream pointer to the associated stream
|
|
* @param audioData buffer containing input data or a place to put output data
|
|
* @param numFrames number of frames to be processed
|
|
* @return DataCallbackResult::Continue or DataCallbackResult::Stop
|
|
*/
|
|
virtual DataCallbackResult onAudioReady(
|
|
AudioStream *oboeStream,
|
|
void *audioData,
|
|
int32_t numFrames) = 0;
|
|
|
|
/**
|
|
* This will be called when an error occurs on a stream or when the stream is disconnected.
|
|
*
|
|
* Note that this will be called on a different thread than the onAudioReady() thread.
|
|
* This thread will be created by Oboe.
|
|
*
|
|
* The underlying stream will already be stopped by Oboe but not yet closed.
|
|
* So the stream can be queried.
|
|
*
|
|
* @param oboeStream pointer to the associated stream
|
|
* @param error
|
|
*/
|
|
virtual void onErrorBeforeClose(AudioStream *oboeStream, Result error) {}
|
|
|
|
/**
|
|
* This will be called when an error occurs on a stream or when the stream is disconnected.
|
|
* The underlying stream will already be stopped AND closed by Oboe.
|
|
* So the underlyng stream cannot be referenced.
|
|
*
|
|
* This callback could be used to reopen a new stream on another device.
|
|
*
|
|
* @param oboeStream pointer to the associated stream
|
|
* @param error
|
|
*/
|
|
virtual void onErrorAfterClose(AudioStream *oboeStream, Result error) {}
|
|
|
|
};
|
|
|
|
} // namespace oboe
|
|
|
|
#endif //OBOE_STREAM_CALLBACK_H
|