Revision control
++ /*
++ Copyright 2018 Google Inc. All Rights Reserved.
++
++ 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
++
++
++ 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 RESONANCE_AUDIO_NODE_PROCESSING_NODE_H_
++ #define RESONANCE_AUDIO_NODE_PROCESSING_NODE_H_
++
++ #include <memory>
++ #include <vector>
++
++ #include "base/audio_buffer.h"
++ #include "node/publisher_node.h"
++ #include "node/subscriber_node.h"
++
++ namespace vraudio {
++
++ // Audio processing node that reads from multiple inputs, processes the
++ // received data and outputs its result.
++ class ProcessingNode : public Node,
++ public SubscriberNode<const AudioBuffer*>,
++ public PublisherNode<const AudioBuffer*> {
++ public:
++ typedef SubscriberNode<const AudioBuffer*> SubscriberNodeType;
++ typedef PublisherNode<const AudioBuffer*> PublisherNodeType;
++
++ // Helper class to manage incoming |AudioBuffer|s.
++ class NodeInput {
++ public:
++ // Constructor.
++ //
++ // @param input_vector Vector containing pointers to incoming
++ // |AudioBuffer|s.
++ explicit NodeInput(const std::vector<const AudioBuffer*>& input_vector);
++
++ // Returns a nullptr if zero or more than one input buffers are available.
++ // Otherwise a pointer to the single input |AudioBuffer| is returned. This
++ // method should be used if only a single input |AudioBuffer| is expected.
++ //
++ // @return Pointer to single input |AudioBuffer|.
++ const AudioBuffer* GetSingleInput() const;
++
++ // Returns vector with input |AudioBuffer|s.
++ //
++ // @return Pointer to single input |AudioBuffer|.
++ const std::vector<const AudioBuffer*>& GetInputBuffers() const;
++
++ // Delete copy constructor.
++ NodeInput(const NodeInput& that) = delete;
++
++ private:
++ // Const reference to vector of input |AudioBuffer|s.
++ const std::vector<const AudioBuffer*>& input_vector_;
++ };
++
++ ProcessingNode();
++
++ // SubscriberNode<InputType> implementation.
++ void Connect(
++ const std::shared_ptr<PublisherNodeType>& publisher_node) override;
++
++ // Node implementation.
++ void Process() final;
++ bool CleanUp() override;
++
++ // By default, calls to AudioProcess() are skipped in case of empty input
++ // buffers. This enables this node to process audio buffers in the absence of
++ // input data (which is needed for instance for a reverberation effect).
++ void EnableProcessOnEmptyInput(bool enable);
++
++ // Disable copy constructor.
++ ProcessingNode(const ProcessingNode& that) = delete;
++
++ protected:
++ // Calls |CleanUp| on all connected input nodes.
++ void CallCleanUpOnInputNodes();
++
++ // Pure virtual method to implement the audio processing method. This method
++ // receives a vector of all input arguments to be processed and requires to
++ // output a single output buffer.
++ //
++ // @param input Input instance to receive pointers to input |AudioBuffer|s.
++ // @return Returns output data.
++ virtual const AudioBuffer* AudioProcess(const NodeInput& input) = 0;
++
++ private:
++ // PublisherNode<OutputType> implementation.
++ std::shared_ptr<Node> GetSharedNodePtr() final;
++ Node::Output<const AudioBuffer*>* GetOutput() final;
++
++ // Input stream to poll for incoming data.
++ Node::Input<const AudioBuffer*> input_stream_;
++
++ // Output stream to write processed data to.
++ Node::Output<const AudioBuffer*> output_stream_;
++
++ // Flag that indicates if |AudioProcess| should be called in case no input
++ // data is available.
++ bool process_on_no_input_;
++ };
++
++ } // namespace vraudio
++
++ #endif // RESONANCE_AUDIO_NODE_PROCESSING_NODE_H_