Rewrite of IBM doublebyte charsets
Ulf.Zibis at gmx.de
Sun May 17 20:11:53 UTC 2009
Am 15.05.2009 01:48, Xueming Shen schrieb:
> Ulf Zibis wrote:
>> 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);
>> 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.
> With the motivation of pushing you move on to the ibm charsets as
> quick as possible:-) I've tried both xor and the
> byte. since we have to do "int cnsPlane = (sa[sp +1] ^ 0xa0) &&
> 0xff;", (without & 0xff, you got a negative
> sign extension),
Oops, it should be "int cnsPlane = (sa[sp +1] ^ (byte)0xa0);"
> it is not faster than the existing one, actually my "not that
> accurate" benchmark shows it is slower...
Maybe XOR is not covered by Bug ID 6797305 ... Christian Thalinger?
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