Add DecodeFlags header function

allows to rewrite flags from .Data bytes into header

pkg/mslnk/header.go

@@ -50,6 +50,31 @@ func (h *header) Update() {
 	}
 }
 
+// writing flags from .Data bytes into header
+func (h *header) DecodeFlags() {
+	var byteIndex, bitIndex int8
+	byteIndex = -1
+	bitIndex = 8
+	for _, k := range LinkFlags {
+		if bitIndex >= 8 {
+			byteIndex += 1
+			bitIndex = 0
+		}
+		h.LinkFlags[k] = bool(h.Data.LinkFlags[byteIndex]&(1<<bitIndex) > 0)
+		bitIndex += 1
+	}
+	byteIndex = -1
+	bitIndex = 8
+	for _, k := range FileAttributesFlags {
+		if bitIndex >= 8 {
+			byteIndex += 1
+			bitIndex = 0
+		}
+		h.FileAttributes[k] = bool(h.Data.FileAttributes[byteIndex]&(1<<bitIndex) > 0)
+		bitIndex += 1
+	}
+}
+
 func (h *header) Bytes() []byte {
 	var buffer bytes.Buffer
 	binary.Write(&buffer, binary.LittleEndian, h.Data)

pkg/mslnk/header_test.go

@@ -28,3 +28,38 @@ func TestHeader(t *testing.T) {
 		t.Errorf("Initialized header\n%v\ndoesn't match template\n%v\n", h.Bytes(), expected)
 	}
 }
+
+func TestHeader_DecodeFlags(t *testing.T) {
+	println("Testing Header DecodeFlags...")
+	h := mslnk.Header()
+	h.Data.LinkFlags = [4]byte{155, 0, 8, 0}
+	h.Data.FileAttributes = [4]byte{32, 0, 0, 0}
+	h.DecodeFlags()
+	// list of expected flags should be in order
+	expected := []string{"HasLinkTargetIDList", "HasLinkInfo", "HasRelativePath", "HasWorkingDir", "IsUnicode", "EnableTargetMetadata", "FILE_ATTRIBUTE_ARCHIVE", ""}
+	var i int = 0
+	for _, k := range mslnk.LinkFlags {
+		if h.LinkFlags[k] {
+			if expected[i] == k {
+				i += 1
+			} else {
+				t.Errorf("Flag %s set when it shouldn't be. Expecting %s first.\n", k, expected[i])
+			}
+		} else if expected[i] == k {
+			t.Errorf("Flag %s not set when it should be.", k)
+			i += 1
+		}
+	}
+	for _, k := range mslnk.FileAttributesFlags {
+		if h.FileAttributes[k] {
+			if expected[i] == k {
+				i += 1
+			} else {
+				t.Errorf("Flag %s set when it shouldn't be. Expecting %s first.\n", k, expected[i])
+			}
+		} else if expected[i] == k {
+			t.Errorf("Flag %s not set when it should be.", k)
+			i += 1
+		}
+	}
+}