private USB.ConfigurationDescriptor ReadConfigurationDescriptor(IUSBDevice device, byte configurationId, out USB.InterfaceDescriptor[] interfaceDescriptors)
{
var setupPacket = new SetupPacket
{
Recipient = PacketRecipient.Device,
Type = PacketType.Standard,
Direction = Direction.DeviceToHost,
Request = (byte)StandardRequest.GetDescriptor,
Value = (ushort)(((int)DescriptorType.Configuration << 8) | configurationId),
Count = (ushort)Packet.CalculateLength <USB.ConfigurationDescriptor>()
};
// first ask for the configuration descriptor non-recursively ...
var configurationDescriptorBytes = HandleSetupPacketSync(device, setupPacket);
var result = Packet.Decode <USB.ConfigurationDescriptor>(configurationDescriptorBytes);
interfaceDescriptors = new USB.InterfaceDescriptor[result.NumberOfInterfaces];
// ... read the total length of a recursive structure ...
setupPacket.Count = result.TotalLength;
// ... and only then read the whole structure again.
var recursiveBytes = HandleSetupPacketSync(device, setupPacket);
var currentOffset = Packet.CalculateLength <USB.ConfigurationDescriptor>();
for (var i = 0; i < interfaceDescriptors.Length; i++)
{
interfaceDescriptors[i] = Packet.Decode <USB.InterfaceDescriptor>(recursiveBytes, currentOffset);
// skip next interface descriptor with associated endpoint descriptors (each of size 7)
currentOffset += Packet.CalculateLength <USBIP.InterfaceDescriptor>()
+ interfaceDescriptors[i].NumberOfEndpoints * 7;
}
return(result);
}
private USB.ConfigurationDescriptor ReadConfigurationDescriptor(IUSBDevice device, byte configurationId, out USB.InterfaceDescriptor[] interfaceDescriptors)
{
var setupPacket = new SetupPacket
{
Recipient = PacketRecipient.Device,
Type = PacketType.Standard,
Direction = Direction.DeviceToHost,
Request = (byte)StandardRequest.GetDescriptor,
Value = (ushort)(((int)DescriptorType.Configuration << 8) | configurationId),
Count = (ushort)Packet.CalculateLength <USB.ConfigurationDescriptor>()
};
// first ask for the configuration descriptor non-recursively ...
var configurationDescriptorBytes = HandleSetupPacketSync(device, setupPacket);
var result = Packet.Decode <USB.ConfigurationDescriptor>(configurationDescriptorBytes);
interfaceDescriptors = new USB.InterfaceDescriptor[result.NumberOfInterfaces];
// ... read the total length of a recursive structure ...
setupPacket.Count = result.TotalLength;
// ... and only then read the whole structure again.
var recursiveBytes = HandleSetupPacketSync(device, setupPacket);
var currentOffset = Packet.CalculateLength <USB.ConfigurationDescriptor>();
for (var i = 0; i < interfaceDescriptors.Length; i++)
{
interfaceDescriptors[i] = Packet.Decode <USB.InterfaceDescriptor>(recursiveBytes, currentOffset);
if (i != interfaceDescriptors.Length - 1)
{
// skip until the next interface descriptor
currentOffset += Packet.CalculateLength <USB.InterfaceDescriptor>();
// the second byte of each descriptor contains the type
while (recursiveBytes[currentOffset + 1] != (byte)DescriptorType.Interface)
{
// the first byte of each descriptor contains the length in bytes
currentOffset += recursiveBytes[currentOffset];
}
}
}
return(result);
}
