Merge pull request #67 from lifeinwild/bugfix/longcompression

bugfix of LongDelta

Author: lemire

src/main/java/me/lemire/longcompression/differential/LongDelta.java

@@ -107,7 +107,7 @@ public static void fastinverseDelta(long[] data) {
                         }
                 }
 
-                for (; i != data.length; ++i) {
+                for (; i < data.length; ++i) {
                         data[i] += data[i - 1];
                 }
         }

src/test/java/me/lemire/longcompression/LongDeltaTest.java

@@ -0,0 +1,23 @@
+package me.lemire.longcompression;
+
+import me.lemire.longcompression.differential.LongDelta;
+import org.junit.Test;
+
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertNotNull;
+
+public class LongDeltaTest {
+    @Test
+    public void testEmptyArrayFastInverseDelta() {
+        LongCompressor compressor = new LongCompressor();
+        long[] input = new long[0];
+
+        LongDelta.delta(input);
+        long[] compressed = compressor.compress(input);
+        long[] result = compressor.uncompress(compressed);
+        LongDelta.fastinverseDelta(result);
+
+        assertNotNull(result);
+        assertArrayEquals(input, result);
+    }
+}