package danger

import (

	"reflect"

	"unsafe"

)

// typeID is used as key in encoder and decoder caches to enable using

// the optimize runtime.mapaccess2_fast64 function instead of the more

// expensive lookup if we were to use reflect.Type as map key.

//

// typeID holds the pointer to the reflect.Type value, which is unique

// in the program.

//

// https://github.com/segmentio/encoding/blob/master/json/codec.go#L59-L61

type TypeID unsafe.Pointer

func MakeTypeID(t reflect.Type) TypeID {

	// reflect.Type has the fields:

	// typ unsafe.Pointer

	// ptr unsafe.Pointer

	return TypeID((*[2]unsafe.Pointer)(unsafe.Pointer(&t))[1])

}