Am 15.05.2009 00:03, Xueming Shen schrieb:
What is the "XOR approach"? I might have miss it. I'm happy to try it
out. OK, the "3 times computing" and "compare <0" are the good hint to
improve, the
latest one looks like
I'm afraid, you really missed it. See my post from 12.05.2009 20:25 CEST
;-)
I mean:
int cnsPlane = sa[sp +1] ^ 0xa0;
if (cnsPlane > 0xf || (cnsPlane = cnspToIndex[cnsPlane]) < 0)
return CoderResult.malformedForLength(2);
or maybe (to force LoadUB (Bug ID 6797305), which may be faster than
sign extension to int):
int cnsPlane = (sa[sp +1] ^ 0xa0) && 0xff;
or maybe use byte[] (to force LoadUB, which may be faster than sign
extension to int):
byte cnsPlane = (byte)(sa[sp +1] ^ 0xa0);
or
byte cnsPlane = (byte)((sa[sp +1] && 0xff) ^ (0xa0 && 0xff));
// don't know if this make a difference
But anyway, I think,
static final byte[] cnspToIndex = new byte[0x100];
...
would be the fastest.
180 int cnsPlane = sa[sp +1];
I guess this is worse, but definitely not better, than
int cnsPlane = sa[sp +1] & 0xff;
Reason:
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6797305
181 if ((cnsPlane & 0xf0) != 0xa0 ||
182 (cnsPlane =
cnspToIndex[cnsPlane&0x0f]) < 0)
183 return CoderResult.malformedForLength(2);
And it definitely is better than the previous one, thanks! :-) Now
maybe you might want to eye the
IBM db webrev, any change would benefit several charsets:-)
... I'm doing that since 2 hours. :-)
-Ulf
