Revise InterfaceInfoList's Item() method

Signed-off-by: Simon Rozman <simon@rozman.si>

wlanapi_windows.go

@@ -66,8 +66,8 @@ func (iil *InterfaceInfoList) Item(idx uint32) *InterfaceInfo {
 	}
 	addr := uintptr(unsafe.Pointer(iil))
 	addr += unsafe.Sizeof(InterfaceInfoList{})
-	iiArray := (*[(1 << 21) - 1]InterfaceInfo)(unsafe.Pointer(addr))
-	return &(*iiArray)[idx]
+	addr += unsafe.Sizeof(InterfaceInfo{}) * uintptr(idx)
+	return (*InterfaceInfo)(unsafe.Pointer(addr))
 }
 
 // Close frees the memory.

wlanapi_windows_test.go

@@ -7,10 +7,20 @@ package wlanapi
 
 import (
 	"testing"
+	"unsafe"
 
 	"golang.org/x/sys/windows"
 )
 
+func TestStruct(t *testing.T) {
+	if unsafe.Sizeof(InterfaceInfo{}) != 532 {
+		t.Errorf("InterfaceInfo wrong size: %v", unsafe.Sizeof(InterfaceInfo{}))
+	}
+	if unsafe.Sizeof(InterfaceInfoList{}) != 8 {
+		t.Errorf("InterfaceInfoList wrong size: %v", unsafe.Sizeof(InterfaceInfoList{}))
+	}
+}
+
 func Test(t *testing.T) {
 	session, version, err := CreateClientSession(2)
 	if err != nil {
@@ -29,13 +39,16 @@ func Test(t *testing.T) {
 
 	for i := uint32(0); i < ifaces.NumberOfItems; i++ {
 		ii := ifaces.Item(i)
+
+		t.Logf("Interface: %v, state: %v, GUID: %v",
+			ii.InterfaceDescription(),
+			ii.State,
+			ii.InterfaceGUID)
+
 		if ii.State == InterfaceStateNotReady {
 			continue
 		}
 
-		desc := ii.InterfaceDescription()
-		t.Logf("Interface: %v", desc)
-
 		err = session.SetProfileEAPXMLUserData(&ii.InterfaceGUID, "foobar", 0, "<foobar></foobar>")
 		if err == nil {
 			t.Errorf("SetProfileEAPXMLUserData error expected")