Re: Bug in [NSScanner scanDouble:]

[Richard Frith-Macdonald]

> On 29 Dec 2020, at 09:32, Fred Kiefer <fredkiefer@gmx.de> wrote:
> 
> Looks like the code of GSScanDouble and [NSScanner scanDouble:] differ a lot. 
> Both are in the file NSScanner.m and it looks like the function has been 
> corrected over the years to handle different cases a lot better. The 
> NSScanner code is just a straight forward number scanning as you would expect.
> 
> The easiest solution would be to reuse GSScanDouble by scanning in a buffer 
> all the characters for the double value and calling the function on that 
> value (handling _decimal by replacing it with a dot). But somehow this feels 
> like the wrong way around.

I think that probably *is* the way to go.  That way the NSScanner method would 
be responsible for converting to a unicode character buffer from whatever 
string representation it is handling (and finding the end of the potential 
double), while the function would be responsible for ensuring that the 
characters in the buffer actually represents a double.  We know the maximum 
number of characters in a double, so we can use an on-stack buffer and the 
whole thing would be reasonably efficient.