JRUBY-5064: ChannelStream#read() should return an unsigned value.

For InputStream compatibility. Reading int from buffered bytes works but
reading from unbeffered bytes did not work.

src/org/jruby/util/io/ChannelStream.java

@@ -1462,7 +1462,8 @@ public int read() throws IOException {
             }
 
             byte[] b = new byte[1];
-            return read(b, 0, 1) == 1 ? b[0] : -1;
+            // java.io.InputStream#read must return an unsigned value;
+            return read(b, 0, 1) == 1 ? b[0] & 0xff: -1;
         }
 
         @Override

test/test_unmarshal.rb

@@ -23,6 +23,17 @@ def testUnmarshal
     flunk "Unmarshalling failed with EOF error at " + result + " string."
   end
 
+  def test_fixnum_unbuffered
+    # need to read unbuffered value from ChannelStream.
+    obj = Array.new(2000, 60803)
+    dump = Marshal.dump(obj)
+    piper, pipew = IO.pipe
+    pipew << dump
+    Marshal.load(piper).each do |e|
+      assert_equal(60803, e, 'JRUBY-5064')
+    end
+  end
+
   # TYPE_IVAR from built-in class
   class C
     def _dump(depth)