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From Daniel John Debrunner <...@debrunners.com>
Subject Re: [PATCH] Optimization of org.apache.derby.impl.services.uuid.BasicUUID.toByteArray()
Date Wed, 01 Sep 2004 16:37:30 GMT
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Jan Hlavatý wrote:

| Removed unnecessary &'s (these are done automatically by conversion to
| byte).
| Saves 32 bytecode instructions as well as several long constants in the
| classfile,
| and should run a bit faster.

I think you are correct, but I also have a very vague memory of some
issues if we didn't use the &'s. I know this is early code and we
(Cloudscape engineers) were following the examples from Sun, e.g. look
at this extract from the Javadoc for java.io.DataOutput.writeShort.

http://java.sun.com/j2se/1.4.2/docs/api/java/io/DataOutput.html#writeShort(int)

The byte values to be written, in the order shown, are:

~ (byte)(0xff & (v >> 8))
~ (byte)(0xff & v)

Dan.


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