| // Copyright 2013 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef MEDIA_MIDI_MIDI_MESSAGE_QUEUE_H_ |
| #define MEDIA_MIDI_MIDI_MESSAGE_QUEUE_H_ |
| |
| #include <stddef.h> |
| #include <stdint.h> |
| |
| #include <vector> |
| |
| #include "base/containers/circular_deque.h" |
| #include "base/macros.h" |
| #include "media/midi/midi_export.h" |
| |
| namespace midi { |
| |
| // A simple message splitter for possibly unsafe/corrupted MIDI data stream. |
| // This class allows you to: |
| // - maintain fragmented MIDI message. |
| // - skip any invalid data sequence. |
| // - reorder MIDI messages so that "System Real Time Message", which can be |
| // inserted at any point of the byte stream, is placed at the boundary of |
| // complete MIDI messages. |
| // - (Optional) reconstruct complete MIDI messages from data stream where |
| // MIDI status byte is abbreviated (a.k.a. "running status"). |
| // |
| // Example (pseudo message loop): |
| // MidiMessageQueue queue(true); // true to support "running status" |
| // while (true) { |
| // if (is_incoming_midi_data_available()) { |
| // std::vector<uint8_t> incoming_data; |
| // read_incoming_midi_data(&incoming_data) |
| // queue.Add(incoming_data); |
| // } |
| // while (true) { |
| // std::vector<uint8_t> next_message; |
| // queue.Get(&next_message); |
| // if (!next_message.empty()) |
| // dispatch(next_message); |
| // } |
| // } |
| class MIDI_EXPORT MidiMessageQueue { |
| public: |
| // Initializes the queue. Set true to |allow_running_status| to enable |
| // "MIDI running status" reconstruction. |
| explicit MidiMessageQueue(bool allow_running_status); |
| ~MidiMessageQueue(); |
| |
| // Enqueues |data| to the internal buffer. |
| void Add(const std::vector<uint8_t>& data); |
| void Add(const uint8_t* data, size_t length); |
| |
| // Fills the next complete MIDI message into |message|. If |message| is |
| // not empty, the data sequence falls into one of the following types of |
| // MIDI message. |
| // - Single "Channel Voice Message" (w/o "System Real Time Messages") |
| // - Single "Channel Mode Message" (w/o "System Real Time Messages") |
| // - Single "System Exclusive Message" (w/o "System Real Time Messages") |
| // - Single "System Common Message" (w/o "System Real Time Messages") |
| // - Single "System Real Time message" |
| // |message| is empty if there is no complete MIDI message any more. |
| void Get(std::vector<uint8_t>* message); |
| |
| private: |
| base::circular_deque<uint8_t> queue_; |
| std::vector<uint8_t> next_message_; |
| const bool allow_running_status_; |
| DISALLOW_COPY_AND_ASSIGN(MidiMessageQueue); |
| }; |
| |
| } // namespace midi |
| |
| #endif // MEDIA_MIDI_MIDI_MESSAGE_QUEUE_H_ |