xerial#89: Fixes SnappyInputStream not to throw an IOException when the input is empty

Author: xerial

src/main/java/org/xerial/snappy/SnappyInputStream.java

@@ -82,7 +82,7 @@ protected void readHeader() throws IOException {
             readBytes += ret;
         }
 
-        // Quick test of the header 
+        // Quick test of the header
         if (readBytes < header.length || header[0] != SnappyCodec.MAGIC_HEADER[0]) {
             // do the default uncompression
             readFully(header, readBytes);
@@ -106,7 +106,11 @@ protected void readHeader() throws IOException {
     }
 
     protected void readFully(byte[] fragment, int fragmentLength) throws IOException {
-        // read the entire input data to the buffer 
+        if(fragmentLength == 0) {
+            finishedReading = true;
+            return;
+        }
+        // read the entire input data to the buffer
         compressed = new byte[Math.max(8 * 1024, fragmentLength)]; // 8K
         System.arraycopy(fragment, 0, compressed, 0, fragmentLength);
         int cursor = fragmentLength;

src/test/java/org/xerial/snappy/SnappyInputStreamTest.java

@@ -62,7 +62,7 @@ public static byte[] readFully(InputStream input) throws IOException {
         }
     }
 
-    public static byte[] biteWiseReadFully(InputStream input) throws IOException {
+    public static byte[] byteWiseReadFully(InputStream input) throws IOException {
         ByteArrayOutputStream out = new ByteArrayOutputStream();
         byte[] buf = new byte[4096];
         for (int readData = 0; (readData = input.read()) != -1;) {
@@ -108,7 +108,7 @@ public void biteWiseRead() throws Exception {
         byte[] compressed = Snappy.compress(orig);
 
         SnappyInputStream in = new SnappyInputStream(new ByteArrayInputStream(compressed));
-        byte[] uncompressed = biteWiseReadFully(in);
+        byte[] uncompressed = byteWiseReadFully(in);
 
         assertEquals(orig.length, uncompressed.length);
         assertArrayEquals(orig, uncompressed);
@@ -129,4 +129,17 @@ public void available() throws Exception {
         in.close();
     }
 
+    @Test
+    public void emptyStream() throws Exception {
+        try {
+            SnappyInputStream in = new SnappyInputStream(new ByteArrayInputStream(new byte[0]));
+            byte[] uncompressed = readFully(in);
+            assertEquals(0, uncompressed.length);
+        }
+        catch(Exception e) {
+            fail("should not reach here");
+        }
+
+    }
+
 }