java-nio-charset-enhanced -- Milestone 4 is released
Ulf.Zibis at gmx.de
Fri Mar 27 20:29:37 UTC 2009
milestone 4 of charset enhancement is released.
- I reduced the jar-footprint, concerning entire single-byte needs,
compared to original JDK 6 binaries, down to 7 %, which also should
perform class loading, (not to forget: encoder maps are lazy
initialized), even though there are added 21 specialized coder algorithms.
- In this release there is only 1 class <SingleByteCharset> for all
single-byte charsets, which reads decoder mapping + all names including
aliases from a small data file (69..731 Bytes, average 250 Bytes). This
is possible, because numerous charsets can inherit their mappings (256
2-byte chars) from each other, and empty or 1:1 ranges (especially
\u0000..\u007F) are filled by constructor.
- Additionally a set of 7 Decoder and 14 Encoder classes do there work,
specially speed + memory optimised for the charsets, having diverse
character spreading and frequency of occurrence. A special MapCalculator
class for playing with different parameters is provided in the test package.
- The aliases and historical names should no more statically and
entirely loaded, provided and linked from StandardCharsets class. They
additionally could be easy edited in files standard-charsets and
extended-charsets (refer Bug Id: 6795538
<http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6795538>). If some
day they are defined entirely upper-case, they could be omitted
completely, as they are redundantly case-standardised existing in the
FastCharsetProvider lookup maps. Determining the 'contains()' references
by this way would be also reasonable (refer Bug Id: 6761481
containment of ASCII is already calculated automatically.
See my projects home: ---> https://java-nio-charset-enhanced.dev.java.net/
I believe, these techniques could also be used for most multi-byte
charsets, especially inheriting maps to reduce entire charsets footprint.
_Outlook Milestone 5_ : Final performance optimisation by dedicated
inlining, exception catching, surrogate handling etc..
*Urgently waiting* for Christian
Thalinger's optimization of "widening conversions".
P.S.: I'm on the way, providing changesets slice by slice for OpenJDK 7.
BTW: Is there a way to add author and/or contributor annotation in the
sources to _honour the investigation of external collaborators_ (almost
1 year in my case)?
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