Add config, interfaces, endpoints, etc

usb/config.go

@@ -0,0 +1,114 @@
+package usb
+
+// #cgo LDFLAGS: -lusb-1.0
+// #include <libusb-1.0/libusb.h>
+import "C"
+
+import (
+	"log"
+	"reflect"
+	"runtime"
+	"unsafe"
+)
+
+type Endpoint struct {
+	Type          DescriptorType
+	Address       ID
+	MaxPacketSize uint16
+	PollInterval  uint8
+	RefreshRate   uint8
+	SynchAddress  ID
+}
+
+type Interface struct {
+	Type       DescriptorType
+	Number     ID
+	Alternate  ID
+	IfClass    Class
+	IfSubClass uint8
+	IfProtocol uint8
+	Endpoints  []*Endpoint
+}
+
+type Config struct {
+	cfg *C.struct_libusb_config_descriptor
+
+	Type       DescriptorType
+	Config     ID
+	Attributes uint8
+	MaxPower   uint8
+	Interfaces [][]*Interface
+}
+
+func newConfig(cfg *C.struct_libusb_config_descriptor) *Config {
+	c := &Config{
+		cfg:        cfg,
+		Type:       DescriptorType(cfg.bDescriptorType),
+		Config:     ID(cfg.bConfigurationValue),
+		Attributes: uint8(cfg.bmAttributes),
+		MaxPower:   uint8(cfg.MaxPower),
+	}
+
+	var ifaces []C.struct_libusb_interface
+	*(*reflect.SliceHeader)(unsafe.Pointer(&ifaces)) = reflect.SliceHeader{
+		Data: uintptr(unsafe.Pointer(cfg._interface)),
+		Len:  int(cfg.bNumInterfaces),
+		Cap:  int(cfg.bNumInterfaces),
+	}
+	c.Interfaces = make([][]*Interface, 0, len(ifaces))
+	for _, iface := range ifaces {
+		var alts []C.struct_libusb_interface_descriptor
+		*(*reflect.SliceHeader)(unsafe.Pointer(&alts)) = reflect.SliceHeader{
+			Data: uintptr(unsafe.Pointer(iface.altsetting)),
+			Len:  int(iface.num_altsetting),
+			Cap:  int(iface.num_altsetting),
+		}
+		descs := make([]*Interface, 0, len(alts))
+		for _, alt := range alts {
+			i := &Interface{
+				Type:       DescriptorType(alt.bDescriptorType),
+				Number:     ID(alt.bInterfaceNumber),
+				Alternate:  ID(alt.bAlternateSetting),
+				IfClass:    Class(alt.bInterfaceClass),
+				IfSubClass: uint8(alt.bInterfaceSubClass),
+				IfProtocol: uint8(alt.bInterfaceProtocol),
+			}
+			var ends []C.struct_libusb_endpoint_descriptor
+			*(*reflect.SliceHeader)(unsafe.Pointer(&ends)) = reflect.SliceHeader{
+				Data: uintptr(unsafe.Pointer(alt.endpoint)),
+				Len:  int(alt.bNumEndpoints),
+				Cap:  int(alt.bNumEndpoints),
+			}
+			i.Endpoints = make([]*Endpoint, 0, len(ends))
+			for _, end := range ends {
+				i.Endpoints = append(i.Endpoints, &Endpoint{
+					Type:          DescriptorType(end.bDescriptorType),
+					Address:       ID(end.bEndpointAddress),
+					MaxPacketSize: uint16(end.wMaxPacketSize),
+					PollInterval:  uint8(end.bInterval),
+					RefreshRate:   uint8(end.bRefresh),
+					SynchAddress:  ID(end.bSynchAddress),
+				})
+			}
+			descs = append(descs, i)
+		}
+		c.Interfaces = append(c.Interfaces, descs)
+	}
+
+	// *sigh*
+	runtime.SetFinalizer(c, (*Config).Close)
+
+	log.Printf("config %p initialized", c.cfg)
+	return c
+}
+
+// Close decrements the reference count for the device in the libusb driver
+// code.  It should be called exactly once!
+func (c *Config) Close() error {
+	if c.cfg != nil {
+		log.Printf("config %p closed", c.cfg)
+		C.libusb_free_config_descriptor(c.cfg)
+	}
+	c.cfg = nil
+	return nil
+}