BufferedFileChannelInputStream.available() should return 0 instead of -1

at the end of the stream

src/changes/changes.xml

@@ -70,6 +70,7 @@ The <action> type attribute can be add,update,fix,remove.
       <action dev="ggregory" type="fix"                due-to="Gary Gregory">Avoid NullPointerException in ProxyInputStream.markSupported() when the underlying input stream is null.</action>
       <action dev="ggregory" type="fix"                due-to="Gary Gregory">Avoid NullPointerException in ProxyInputStream.mark(int) when the underlying input stream is null.</action>
       <action dev="ggregory" type="fix"                due-to="Gary Gregory">BufferedFileChannelInputStream.available() returns 0 before any reads.</action>
+      <action dev="ggregory" type="fix"                due-to="Gary Gregory">BufferedFileChannelInputStream.available() should return 0 instead of -1 at the end of the stream.</action>
       <action dev="ggregory" type="fix"                due-to="Gary Gregory">BufferedFileChannelInputStream.available() should return 0 when the stream is closed instead of throwing an exception.</action>      
       <action dev="ggregory" type="fix"                due-to="Gary Gregory">CharSequenceInputStream.available() should return 0 after the stream is closed.</action>
       <action dev="ggregory" type="fix"                due-to="Gary Gregory">BoundedInputStream.available() should return 0 when the stream is closed.</action>

src/main/java/org/apache/commons/io/input/BufferedFileChannelInputStream.java

@@ -173,7 +173,7 @@ public synchronized int available() throws IOException {
             return 0;
         }
         if (!refill()) {
-            return EOF;
+            return 0;
         }
         return byteBuffer.remaining();
     }

src/test/java/org/apache/commons/io/input/AbstractInputStreamTest.java

@@ -91,6 +91,14 @@ public void testAvailableAfterRead() throws Exception {
         }
     }
 
+    @Test
+    public void testAvailableAtEnd() throws Exception {
+        for (final InputStream inputStream : inputStreams) {
+            IOUtils.consume(inputStream);
+            assertEquals(0, inputStream.available());
+        }
+    }
+
     @Test
     public void testBytesSkipped() throws IOException {
         for (final InputStream inputStream : inputStreams) {