Codereview request for 7183053: Optimize DoubleByte charset for String.getBytes()/new String(byte[])

[Xueming Shen]

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

The results of the "non -scientific" benchmark StrCodingBenchmarkDB 
running on client
and server vm on my linux machine are included in docs_c (client) and 
docs_s(server)
below.

http://cr.openjdk.java.net/~sherman/7183053/dbcs_c
http://cr.openjdk.java.net/~sherman/7183053/dbcs_s

Numbers are the time spent on the decoding/encoding operations, the 
smaller the
better.

Thanks,
-Sherman