integer fd filedescriptor / mapping special files

Hi list -

I've been using this patch for years to a) allow access to the integer
file descriptor in jni as in [1], and b) to use the FileChannel.map()
method to map special files under linux using jamvm / classpath-0.98
(e.g. /dev/fb0).

Thought I would submit it to the list for inclusion in any new releases.

Feedback from any people wanting to validate is welcome.

If I recall correctly, one shortcoming is that the returned mapped
byte buffer is not 'direct'. Getting a direct map would require some
manipulation of fields in an underlying byte[] somewhere. Obviously, a
direct-mapped byte buffer would be more ideal. I think that requires
using some kind of Unsafe class somewhere, and I stopped at that
point. I don't mind doing the legwork for a direct mapped byte buffer
too, to make it for inclusion in the next release.

C

[1] http://www.kfu.com/~nsayer/Java/jni-filedesc.html

diff --git a/gnu/java/nio/FileChannelImpl.java b/gnu/java/nio/FileChannelImpl.java
index d4a374b..06fa205 100644
--- a/gnu/java/nio/FileChannelImpl.java
+++ b/gnu/java/nio/FileChannelImpl.java
@@ -176,7 +176,7 @@ public final class FileChannelImpl extends FileChannel
    *