fix sciter.Value SetString wrong lenght of encoded utf16 []byte

Author: Orange-iMac

sciter.go

@@ -1866,8 +1866,9 @@ func (pdst *Value) SetString(str string, uintType ...int) error {
 	}
 	cpdst := (*C.VALUE)(unsafe.Pointer(pdst))
 	// args
-	chars := (C.LPCWSTR)(unsafe.Pointer(StringToUTF16Ptr(str)))
-	numChars := (C.UINT)(len(str))
+	pStr, length := StringToUTF16PtrWithLen(str)
+	chars := (C.LPCWSTR)(unsafe.Pointer(pStr))
+	numChars := (C.UINT)(length)
 	// cgo call
 	return wrapValueResult(VALUE_RESULT(C.ValueStringDataSet(cpdst, chars, numChars, sType)), "ValueStringDataSet")
 }

utils.go

@@ -78,6 +78,12 @@ func StringToUTF16Ptr(s string) *uint16 {
 	return &us[0]
 }
 
+func StringToUTF16PtrWithLen(s string) (*uint16, int) {
+	us, _ := Utf16FromString(s)
+	length := len(us) - 1
+	return &us[0], length
+}
+
 func BytePtrToBytes(bp *byte, size uint) []byte {
 	bs := []byte{}
 	p := uintptr(unsafe.Pointer(bp))