On 11/07/2012 00:11, Xueming Shen wrote:
Hi,
In JDK7, the decoder and encoder implementation of most of our
single-byte charsets
and UTF-8 charset are optimized to implement the internal interfce
sun.nio.cs.ArrayDecoder/
Encoder to provide a fastpath for String.getBytes(...) and new
String(byte[]...) operations. I
have an old blog regarding this optimization at
https://blogs.oracle.com/xuemingshen/entry/faster_new_string_bytes_cs
This rfe, as the followup for above changes, is to implement
ArrayDe/Encoder for most
of the sun.nio.cs.ext.DoubleByte based double-byte charsets. Here is
the webrev
http://cr.openjdk.java.net/~sherman/7183053/webrev
I've taken a pass over this and it's great to see
DoubleByte.Decoder/Encoder implementing sun.nio.cs.ArrayDecoder/Encoder.
The results looks good too, a small number of regressions (Big5 at
len=32 for example) but this is a micro benchmark and I'm sure there are
fluctuations. I don't see anything obviously wrong with the EBCDIC
changes I'd need a history book to remember how the shifts between DBCS
and SBCS. I think our tests our good for this area so I'm happy. One
minor nit is the continue in both encode methods, I think it would be
cleaner to use "else if (bb ..." instead.
I see in TestStringCoding.java that you've commented out the test that
goes over the buffer limit - would I be correct to say that this isn't
an issue and this happens with DB charsets today?
Ulf - you've got several patches to the double byte charsets and I
wonder if you have cycles to try Sherman's patch with jdk8 to see if
there is any more to be gained?
-Alan.
