media/midi/usb_midi_input_stream.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef MEDIA_MIDI_USB_MIDI_INPUT_STREAM_H_
   6 #define MEDIA_MIDI_USB_MIDI_INPUT_STREAM_H_
   7
   8 #include <map>
   9 #include <vector>
  10
  11 #include "base/basictypes.h"
  12 #include "base/containers/hash_tables.h"
  13 #include "base/time/time.h"
  14 #include "media/base/media_export.h"
  15 #include "media/midi/usb_midi_jack.h"
  16
  17 namespace media {
  18
  19 class UsbMidiDevice;
  20
  21 // UsbMidiInputStream converts USB-MIDI data to MIDI data.
  22 // See "USB Device Class Definition for MIDI Devices" Release 1.0,
  23 // Section 4 "USB-MIDI Event Packets" for details.
  24 class MEDIA_EXPORT UsbMidiInputStream {
  25  public:
  26   class MEDIA_EXPORT Delegate {
  27    public:
  28     virtual ~Delegate() {}
  29     // This function is called when some data arrives to a USB-MIDI jack.
  30     // An input USB-MIDI jack corresponds to an input MIDIPortInfo.
  31     virtual void OnReceivedData(size_t jack_index,
  32                                 const uint8* data,
  33                                 size_t size,
  34                                 base::TimeTicks time) = 0;
  35   };
  36
  37   // This is public for testing.
  38   struct JackUniqueKey {
  39     JackUniqueKey(UsbMidiDevice* device, int endpoint_number, int cable_number);
  40     bool operator==(const JackUniqueKey& that) const;
  41     bool operator<(const JackUniqueKey& that) const;
  42
  43     UsbMidiDevice* device;
  44     int endpoint_number;
  45     int cable_number;
  46   };
  47
  48   explicit UsbMidiInputStream(Delegate* delegate);
  49   ~UsbMidiInputStream();
  50
  51   void Add(const UsbMidiJack& jack);
  52
  53   // This function should be called when some data arrives to a USB-MIDI
  54   // endpoint. This function converts the data to MIDI data and call
  55   // |delegate->OnReceivedData| with it.
  56   // |size| must be a multiple of |kPacketSize|.
  57   void OnReceivedData(UsbMidiDevice* device,
  58                       int endpoint_number,
  59                       const uint8* data,
  60                       size_t size,
  61                       base::TimeTicks time);
  62
  63   const std::vector<UsbMidiJack>& jacks() const { return jacks_; }
  64
  65  private:
  66   static const size_t kPacketSize = 4;
  67   // Processes a USB-MIDI Event Packet.
  68   // The first |kPacketSize| bytes of |packet| must be accessible.
  69   void ProcessOnePacket(UsbMidiDevice* device,
  70                         int endpoint_number,
  71                         const uint8* packet,
  72                         base::TimeTicks time);
  73
  74   std::vector<UsbMidiJack> jacks_;
  75   // A map from UsbMidiJack to its index in |jacks_|.
  76   std::map<JackUniqueKey, size_t> jack_dictionary_;
  77
  78   // Not owned
  79   Delegate* delegate_;
  80
  81   DISALLOW_COPY_AND_ASSIGN(UsbMidiInputStream);
  82 };
  83
  84 }  // namespace media
  85
  86 #endif  // MEDIA_MIDI_USB_MIDI_INPUT_STREAM_H_