Re: [cp-patches] RFC: patch for Unicode scalar value to UTF-16 conversion

[Chris Burdess]

Tom Tromey wrote:
> Chris> Please comment.
> 
> Chris> -        dst[dstIndex + 1] = (char) ((codePoint & 0x3ff)
> Chris> -                                    + (int) MIN_LOW_SURROGATE );
> Chris> -        dst[dstIndex] = (char) ((codePoint >> 10) + (int) 
> MIN_HIGH_SURROGATE);
> Chris> +        dst[dstIndex + 1] = (char) (((codePoint - 0x10000) % 0x400) + 
> 0xdc00);
> Chris> +        dst[dstIndex] = (char) (((codePoint - 0x10000) / 0x400) + 
> 0xd800);
> 
> I think it is better to use the named constants instead of the values.

Fair enough, but what about the casting: doesn't that make it less efficient?
Actually I should only be doing the subtraction once here on that basis.

> I also have a mild preference for the bit-shifting and masking
> computation, but this is more minor.

The problem is that the bit-shifting method produces the wrong result.

What about the version attached here, is that better?
-- 
Chris Burdess
  "They that can give up essential liberty to obtain a little safety
  deserve neither liberty nor safety." - Benjamin Franklin

patch
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pgpXjinYxOyys.pgp
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