| // Copyright 2014 The Chromium Authors |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "media/midi/usb_midi_descriptor_parser.h" |
| |
| #include "base/logging.h" |
| #include "base/ranges/algorithm.h" |
| #include "base/strings/stringprintf.h" |
| |
| namespace midi { |
| |
| namespace { |
| |
| // The constants below are specified in USB spec, USB audio spec |
| // and USB midi spec. |
| |
| enum DescriptorType { |
| TYPE_DEVICE = 1, |
| TYPE_CONFIGURATION = 2, |
| TYPE_STRING = 3, |
| TYPE_INTERFACE = 4, |
| TYPE_ENDPOINT = 5, |
| TYPE_DEVICE_QUALIFIER = 6, |
| TYPE_OTHER_SPEED_CONFIGURATION = 7, |
| TYPE_INTERFACE_POWER = 8, |
| |
| TYPE_CS_INTERFACE = 36, |
| TYPE_CS_ENDPOINT = 37, |
| }; |
| |
| enum DescriptorSubType { |
| SUBTYPE_MS_DESCRIPTOR_UNDEFINED = 0, |
| SUBTYPE_MS_HEADER = 1, |
| SUBTYPE_MIDI_IN_JACK = 2, |
| SUBTYPE_MIDI_OUT_JACK = 3, |
| SUBTYPE_ELEMENT = 4, |
| }; |
| |
| enum JackType { |
| JACK_TYPE_UNDEFINED = 0, |
| JACK_TYPE_EMBEDDED = 1, |
| JACK_TYPE_EXTERNAL = 2, |
| }; |
| |
| const uint8_t kAudioInterfaceClass = 1; |
| const uint8_t kAudioMidiInterfaceSubclass = 3; |
| |
| bool DecodeBcd(uint8_t byte, int* decoded) { |
| // Write decoded decimal value from |byte| into |decoded|. If either nibble in |
| // |byte| exceeds decimal 10, returns false. |
| const uint8_t k_nibble_ten = 0xa; |
| const uint8_t nibble_major = (byte & 0xf0) >> 4; |
| const uint8_t nibble_minor = byte & 0x0f; |
| if (nibble_major >= k_nibble_ten || nibble_minor >= k_nibble_ten) { |
| return false; |
| } |
| *decoded = nibble_major * 10 + nibble_minor; |
| return true; |
| } |
| |
| } // namespace |
| |
| std::string UsbMidiDescriptorParser::DeviceInfo::BcdVersionToString( |
| uint16_t version) { |
| const int byte_1 = version >> 8; |
| const int byte_2 = version & 0xff; |
| int version_major, version_minor; |
| if (!DecodeBcd(byte_1, &version_major) || |
| !DecodeBcd(byte_2, &version_minor)) { |
| return base::StringPrintf("Invalid BCD $%02x.%02x", byte_1, byte_2); |
| } |
| return base::StringPrintf("%d.%02d", version_major, version_minor); |
| } |
| |
| UsbMidiDescriptorParser::UsbMidiDescriptorParser() |
| : is_parsing_usb_midi_interface_(false), |
| current_endpoint_address_(0), |
| current_cable_number_(0) {} |
| |
| UsbMidiDescriptorParser::~UsbMidiDescriptorParser() = default; |
| |
| bool UsbMidiDescriptorParser::Parse(UsbMidiDevice* device, |
| const uint8_t* data, |
| size_t size, |
| std::vector<UsbMidiJack>* jacks) { |
| jacks->clear(); |
| bool result = ParseInternal(device, data, size, jacks); |
| if (!result) |
| jacks->clear(); |
| Clear(); |
| return result; |
| } |
| |
| bool UsbMidiDescriptorParser::ParseDeviceInfo(const uint8_t* data, |
| size_t size, |
| DeviceInfo* info) { |
| *info = DeviceInfo(); |
| for (const uint8_t* current = data; current < data + size; |
| current += current[0]) { |
| uint8_t length = current[0]; |
| if (length < 2) { |
| DVLOG(1) << "Descriptor Type is not accessible."; |
| return false; |
| } |
| if (current + length > data + size) { |
| DVLOG(1) << "The header size is incorrect."; |
| return false; |
| } |
| DescriptorType descriptor_type = static_cast<DescriptorType>(current[1]); |
| if (descriptor_type != TYPE_DEVICE) |
| continue; |
| // We assume that ParseDevice doesn't modify |*info| if it returns false. |
| return ParseDevice(current, length, info); |
| } |
| // No DEVICE descriptor is found. |
| return false; |
| } |
| |
| bool UsbMidiDescriptorParser::ParseInternal(UsbMidiDevice* device, |
| const uint8_t* data, |
| size_t size, |
| std::vector<UsbMidiJack>* jacks) { |
| for (const uint8_t* current = data; current < data + size; |
| current += current[0]) { |
| uint8_t length = current[0]; |
| if (length < 2) { |
| DVLOG(1) << "Descriptor Type is not accessible."; |
| return false; |
| } |
| if (current + length > data + size) { |
| DVLOG(1) << "The header size is incorrect."; |
| return false; |
| } |
| DescriptorType descriptor_type = static_cast<DescriptorType>(current[1]); |
| if (descriptor_type != TYPE_INTERFACE && !is_parsing_usb_midi_interface_) |
| continue; |
| |
| switch (descriptor_type) { |
| case TYPE_INTERFACE: |
| if (!ParseInterface(current, length)) |
| return false; |
| break; |
| case TYPE_CS_INTERFACE: |
| // We are assuming that the corresponding INTERFACE precedes |
| // the CS_INTERFACE descriptor, as specified. |
| if (!ParseCSInterface(device, current, length)) |
| return false; |
| break; |
| case TYPE_ENDPOINT: |
| // We are assuming that endpoints are contained in an interface. |
| if (!ParseEndpoint(current, length)) |
| return false; |
| break; |
| case TYPE_CS_ENDPOINT: |
| // We are assuming that the corresponding ENDPOINT precedes |
| // the CS_ENDPOINT descriptor, as specified. |
| if (!ParseCSEndpoint(current, length, jacks)) |
| return false; |
| break; |
| default: |
| // Ignore uninteresting types. |
| break; |
| } |
| } |
| return true; |
| } |
| |
| bool UsbMidiDescriptorParser::ParseDevice(const uint8_t* data, |
| size_t size, |
| DeviceInfo* info) { |
| if (size < 0x12) { |
| DVLOG(1) << "DEVICE header size is incorrect."; |
| return false; |
| } |
| |
| info->vendor_id = data[8] | (data[9] << 8); |
| info->product_id = data[0xa] | (data[0xb] << 8); |
| info->bcd_device_version = data[0xc] | (data[0xd] << 8); |
| info->manufacturer_index = data[0xe]; |
| info->product_index = data[0xf]; |
| return true; |
| } |
| |
| bool UsbMidiDescriptorParser::ParseInterface(const uint8_t* data, size_t size) { |
| if (size != 9) { |
| DVLOG(1) << "INTERFACE header size is incorrect."; |
| return false; |
| } |
| incomplete_jacks_.clear(); |
| |
| uint8_t interface_class = data[5]; |
| uint8_t interface_subclass = data[6]; |
| |
| // All descriptors of endpoints contained in this interface |
| // precede the next INTERFACE descriptor. |
| is_parsing_usb_midi_interface_ = |
| interface_class == kAudioInterfaceClass && |
| interface_subclass == kAudioMidiInterfaceSubclass; |
| return true; |
| } |
| |
| bool UsbMidiDescriptorParser::ParseCSInterface(UsbMidiDevice* device, |
| const uint8_t* data, |
| size_t size) { |
| // Descriptor Type and Descriptor Subtype should be accessible. |
| if (size < 3) { |
| DVLOG(1) << "CS_INTERFACE header size is incorrect."; |
| return false; |
| } |
| |
| DescriptorSubType subtype = static_cast<DescriptorSubType>(data[2]); |
| |
| if (subtype != SUBTYPE_MIDI_OUT_JACK && |
| subtype != SUBTYPE_MIDI_IN_JACK) |
| return true; |
| |
| if (size < 6) { |
| DVLOG(1) << "CS_INTERFACE (MIDI JACK) header size is incorrect."; |
| return false; |
| } |
| uint8_t jack_type = data[3]; |
| uint8_t id = data[4]; |
| if (jack_type == JACK_TYPE_EMBEDDED) { |
| // We can't determine the associated endpoint now. |
| incomplete_jacks_.push_back(UsbMidiJack(device, id, 0, 0)); |
| } |
| return true; |
| } |
| |
| bool UsbMidiDescriptorParser::ParseEndpoint(const uint8_t* data, size_t size) { |
| if (size < 4) { |
| DVLOG(1) << "ENDPOINT header size is incorrect."; |
| return false; |
| } |
| current_endpoint_address_ = data[2]; |
| current_cable_number_ = 0; |
| return true; |
| } |
| |
| bool UsbMidiDescriptorParser::ParseCSEndpoint(const uint8_t* data, |
| size_t size, |
| std::vector<UsbMidiJack>* jacks) { |
| const size_t kSizeForEmptyJacks = 4; |
| // CS_ENDPOINT must be of size 4 + n where n is the number of associated |
| // jacks. |
| if (size < kSizeForEmptyJacks) { |
| DVLOG(1) << "CS_ENDPOINT header size is incorrect."; |
| return false; |
| } |
| uint8_t num_jacks = data[3]; |
| if (size != kSizeForEmptyJacks + num_jacks) { |
| DVLOG(1) << "CS_ENDPOINT header size is incorrect."; |
| return false; |
| } |
| |
| for (size_t i = 0; i < num_jacks; ++i) { |
| uint8_t jack = data[kSizeForEmptyJacks + i]; |
| auto it = |
| base::ranges::find(incomplete_jacks_, jack, &UsbMidiJack::jack_id); |
| if (it == incomplete_jacks_.end()) { |
| DVLOG(1) << "A non-existing MIDI jack is associated."; |
| return false; |
| } |
| if (current_cable_number_ > 0xf) { |
| DVLOG(1) << "Cable number should range from 0x0 to 0xf."; |
| return false; |
| } |
| // CS_ENDPOINT follows ENDPOINT and hence we can use the following |
| // member variables. |
| it->cable_number = current_cable_number_++; |
| it->endpoint_address = current_endpoint_address_; |
| jacks->push_back(*it); |
| incomplete_jacks_.erase(it); |
| } |
| return true; |
| } |
| |
| void UsbMidiDescriptorParser::Clear() { |
| is_parsing_usb_midi_interface_ = false; |
| current_endpoint_address_ = 0; |
| current_cable_number_ = 0; |
| incomplete_jacks_.clear(); |
| } |
| |
| } // namespace midi |