Rewrite of IBM doublebyte charsets

[Ulf Zibis]

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);
>> 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.
> With the motivation of pushing you move on to the ibm charsets as 
> quick as possible:-) I've tried both xor and the
> byte[256]. 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?

-Ulf