Add Image.Length()

Signed-off-by: Yoan Blanc <yoan@dosimple.ch>

image.go

@@ -217,7 +217,12 @@ func (i *Image) Size() (ImageSize, error) {
 	return Size(i.buffer)
 }
 
-// Image returns the current resultant image image buffer.
+// Image returns the current resultant image buffer.
 func (i *Image) Image() []byte {
 	return i.buffer
 }
+
+// Length returns the size in bytes of the image buffer.
+func (i *Image) Length() int {
+	return len(i.buffer)
+}

image_test.go

@@ -475,6 +475,17 @@ func TestImageSmartCrop(t *testing.T) {
 	Write("fixtures/test_smart_crop.jpg", buf)
 }
 
+func TestImageLength(t *testing.T) {
+	i := initImage("test.jpg")
+
+	actual := i.Length()
+	expected := 53653
+
+	if expected != actual {
+		t.Errorf("Size in Bytes of the image doesn't correspond. %d != %d", expected, actual)
+	}
+}
+
 func initImage(file string) *Image {
 	buf, _ := imageBuf(file)
 	return NewImage(buf)