Introduce USB MIDI descriptor parser

media/midi/usb_midi_descriptor_parser.h

+// 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_USB_MIDI_DESCRIPTOR_PARSER_H_
+#define MEDIA_MIDI_USB_MIDI_DESCRIPTOR_PARSER_H_
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "media/base/media_export.h"
+#include "media/midi/usb_midi_jack.h"
+
+namespace media {
+
+class UsbMidiDevice;
+
+// UsbMidiDescriptorParser parses USB descriptors and
+// generates input / output lists of MIDIPortInfo.
+// This is not a generic USB descriptor parser: this parser is designed
+// for collecting USB-MIDI jacks information from the descriptor.
+class MEDIA_EXPORT UsbMidiDescriptorParser {
+ public:
+  UsbMidiDescriptorParser();
+  ~UsbMidiDescriptorParser();
+
+  // Returns true if the operation succeeds.
+  // When an incorrect input is given, this method may return true but
+  // never crashes.
+  bool Parse(UsbMidiDevice* device,
+             const uint8* data,
+             size_t size,
+             std::vector<UsbMidiJack>* jacks);
+
+ private:
+  bool ParseInternal(UsbMidiDevice* device,
+                     const uint8* data,
+                     size_t size,
+                     std::vector<UsbMidiJack>* jacks);
+  bool ParseInterface(const uint8* data, size_t size);
+  bool ParseCSInterface(UsbMidiDevice* device, const uint8* data, size_t size);
+  bool ParseEndpoint(const uint8* data, size_t size);
+  bool ParseCSEndpoint(const uint8* data,
+                       size_t size,
+                       std::vector<UsbMidiJack>* jacks);
+  void Clear();
+
+  bool is_parsing_usb_midi_interface_;
+  uint8 current_endpoint_address_;
+  uint8 current_cable_number_;
+
+  std::vector<UsbMidiJack> incomplete_jacks_;
+
+  DISALLOW_COPY_AND_ASSIGN(UsbMidiDescriptorParser);
+};
+
+
+}  // namespace media
+
+#endif  // MEDIA_MIDI_USB_MIDI_DESCRIPTOR_PARSER_H_