On 04/28/2008 01:45 PM, Outside - Karl's ACM wrote:
Exciting conversations this morning. ;)
I also have a personal interest in a multithread safe, nonblocking,
bytecode targeting DFA (and Thompson NFA?) compiler. If such a project
exists or is forming I would like to become involved.
Great!
With regards to mutating the mark / limit of buffers would anyone favor
method invariants that can be checked in a test pipeline and not in the
production pipeline? Another pattern I have used when dealing with
ByteBuffers is to .slice() and then move the position ahead on the
original buffer after the call (slightly slower than invariants).
DIRMINA-490 was all about adding this functionality (sort of a "consuming"
slice() if you will). I've also solved this problem with standard NIO
ByteBuffers more times than I care to think about. :-)
Usually I just have an IoUtil class or something with a static method..
something like this:
// untested by the way ;-)
public static ByteBuffer sliceBuffer(ByteBuffer buffer, int sliceSize) {
if (sliceSize > buffer.remaining() || sliceSize <
-buffer.remaining()) {
throw new BufferUnderflowException();
}
final int oldPos = buffer.position();
final int oldLim = buffer.limit();
if (sliceSize < 0) {
// count from end
buffer.position(oldPos - sliceSize);
try {
return buffer.slice();
} finally {
buffer.position(oldPos);
buffer.limit(oldLim + sliceSize);
}
} else {
// count from start
buffer.limit(oldLim - sliceSize);
try {
return buffer.slice();
} finally {
buffer.position(oldPos + sliceSize);
buffer.limit(oldLim);
}
}
}
- DML
