media/midi/usb_midi_descriptor_parser.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_DESCRIPTOR_PARSER_H_
   6 #define MEDIA_MIDI_USB_MIDI_DESCRIPTOR_PARSER_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/basictypes.h"
  12 #include "media/base/media_export.h"
  13 #include "media/midi/usb_midi_jack.h"
  14
  15 namespace media {
  16
  17 class UsbMidiDevice;
  18
  19 // UsbMidiDescriptorParser parses USB descriptors and
  20 // generates input / output lists of MIDIPortInfo.
  21 // This is not a generic USB descriptor parser: this parser is designed
  22 // for collecting USB-MIDI jacks information from the descriptor.
  23 class MEDIA_EXPORT UsbMidiDescriptorParser {
  24  public:
  25   struct DeviceInfo {
  26     DeviceInfo()
  27         : vendor_id(0),
  28           product_id(0),
  29           bcd_device_version(0),
  30           manufacturer_index(0),
  31           product_index(0) {}
  32     uint16 vendor_id;
  33     uint16 product_id;
  34     // The higher one byte represents the "major" number and the lower one byte
  35     // represents the "minor" number.
  36     uint16 bcd_device_version;
  37     uint8 manufacturer_index;
  38     uint8 product_index;
  39
  40     static std::string BcdVersionToString(uint16);
  41   };
  42
  43   UsbMidiDescriptorParser();
  44   ~UsbMidiDescriptorParser();
  45
  46   // Returns true if the operation succeeds.
  47   // When an incorrect input is given, this method may return true but
  48   // never crashes.
  49   bool Parse(UsbMidiDevice* device,
  50              const uint8* data,
  51              size_t size,
  52              std::vector<UsbMidiJack>* jacks);
  53
  54   bool ParseDeviceInfo(const uint8* data, size_t size, DeviceInfo* info);
  55
  56  private:
  57   bool ParseInternal(UsbMidiDevice* device,
  58                      const uint8* data,
  59                      size_t size,
  60                      std::vector<UsbMidiJack>* jacks);
  61   bool ParseDevice(const uint8* data, size_t size, DeviceInfo* info);
  62   bool ParseInterface(const uint8* data, size_t size);
  63   bool ParseCSInterface(UsbMidiDevice* device, const uint8* data, size_t size);
  64   bool ParseEndpoint(const uint8* data, size_t size);
  65   bool ParseCSEndpoint(const uint8* data,
  66                        size_t size,
  67                        std::vector<UsbMidiJack>* jacks);
  68   void Clear();
  69
  70   bool is_parsing_usb_midi_interface_;
  71   uint8 current_endpoint_address_;
  72   uint8 current_cable_number_;
  73
  74   std::vector<UsbMidiJack> incomplete_jacks_;
  75
  76   DISALLOW_COPY_AND_ASSIGN(UsbMidiDescriptorParser);
  77 };
  78
  79
  80 }  // namespace media
  81
  82 #endif  // MEDIA_MIDI_USB_MIDI_DESCRIPTOR_PARSER_H_