🚧 Add Defrag function

defrag.go

@@ -0,0 +1,26 @@
+package defrag
+
+// Defrag performs an in-place sort of blocks.
+// If an error occurs during processing, it will be returned. The slice may have been partially sorted.
+func Defrag(blocks []byte) error {
+	lastPulled := len(blocks)
+	lastPushed := -1
+	for block := 0; block < len(blocks); block++ {
+		if blocks[block] != '.' {
+			continue
+		}
+		if lastPulled <= block {
+			break
+		}
+		for swap := lastPulled - 1; swap > lastPushed; swap-- {
+			if blocks[swap] == '.' {
+				continue
+			}
+			blocks[block], blocks[swap] = blocks[swap], blocks[block]
+			lastPulled = swap
+			lastPushed = block
+			break
+		}
+	}
+	return nil
+}