Resend: implement _ismbcalpha, _ismbcalnum

[Greg Turner]

On Saturday 16 November 2002 03:52 am, Dmitry Timoshkov wrote:
> "Greg Turner" <gmturner007 at ameritech.net> wrote:
> > So, I think, I
> > should #ifdef the byte-swapping based on the endianness of the
> > target platform (little-endian hosts byte-swap, big-endian hosts
> > don't).... does that sound right?
>
> I think there is no need for #ifdef's.
> Something like this should work:
>
>     if (ch < 256)
>     {
>         mbch[0] = ch & 0xff;
>         n_chars = 1;
>     }
>     else /* multibyte character */
>     {
>         mbch[0] = (ch >> 8) & 0xff;
>         mbch[1] = ch & 0xff;
>         n_chars = 2;
>     }

Of course, you are right -- that looks great.  Now I just have to figure 
out that codepage thing, and I should be set.

An interesting side note: Microsoft claims that their implementations of 
these functions are blindingly fast (they said something along the 
lines that calling these is faster than "if (((0xXX <= ch) && (ch <= 
0xYY)) || ((0xAA <= ch) && (ch <=0xBB)))").  I wonder if this means 
they are using a lookup table in their implementation?  Not planning to 
implement any such thing myself, of course, but I did find it to be an 
intrigueing statement.

-- 
gmt

"War is an ugly thing, but not the ugliest of things;
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