Re: Still gettiing a BadConversion thrown with mySQL++ 3.0 RC1 from a DECIMAL

[Jonathan Wakely]

On 21/01/2008, Jonathan Wakely <mysql@stripped> wrote:
>
> That would get rid of the conv_promotion and proxy templates
> completely and would also allow better names that typeid() provides on
> some compilers.

P.S. another benefit of the iostream version is that it would be
easier to change the types used for the conversions in some future
version. The C library doesn't offer strtoui or strtouc for unsigned
ints or chars, so it would be difficult to detect overflow of e.g.
"257" -> char using the C library functions. Using do_conv from the
patch, you could easily add a String::checked_conv() member function,
which would pass the unpromoted type directly to do_conv and have the
stringstream do range checking. No changes would be needed to do_conv
to make that work.  It would be considerably harder to add a
checked_conv() using the C strtoX functions  :-)

If any of the stream code in do_conv isn't obvious please ask and I'll
explain what's checked for and what isn't. I've just noticed that I
think the stream version would reject "1." -> int, which the current
code accepts. That can be fixed by adding c = '0'; just before the
while loop, so that "1." is treated the same as "1.0"

Jon