Re: [boost] Portable binary integers [was generic polyvalent I/O]

From: Greg Colvin (gcolvin_at_[hidden])
Date: 2000-11-16 15:46:20

True enough.  One reasonable approach is to use BCD and
a 0xf or two as the terminator.

From: David Abrahams <abrahams_at_[hidden]>
> It /saves/ lots of space if most of your numbers are near 0, which is
> common.
> 
> -Dave
> 
> ----- Original Message -----
> From: "Greg Colvin" <gcolvin_at_[hidden]>
> To: <boost_at_[hidden]>
> Sent: Thursday, November 16, 2000 3:27 PM
> Subject: Re: [boost] Portable binary integers [was generic polyvalent I/O]
> 
> 
> > > My feeling has always been that a compact, machine-independent,
> > > variable-length number representation (e.g. high bit set indicates the
> end
> > > of the number) was the way to go if you care about portability at all.
> The
> > > length of an int/long/char/short/wchar_t/float/double... on any given
> > > machine is too variable to make this work otherwise. It's also nice
> because
> > > you can detect overflows.
> >
> > That works, although it wastes some space and time.  It seems that if
> > you provide 1,2,4, and 8 byte signed and unsigned integers and 4 and
> > 8 byte IEEE floats you have pretty well covered the waterfront.
> >
> > > -Dave
> > > ----- Original Message -----
> > > From: "Gary Powell" <Gary.Powell_at_[hidden]>
> > > To: <boost_at_[hidden]>
> > > Sent: Thursday, November 16, 2000 1:32 PM
> > > Subject: RE: [boost] Portable binary integers [was generic polyvalent
> I/O]
> > >
> > >
> > > > >my "angle of attack" on this problem.
> > > >
> > > > I was thinking along the line of having a full set of operators, which
> if
> > > > you selected "arithmetic<native>" "input<BigEndian>"
> > > "output<LittleEndian>"
> > > > traits would do conversion on operator>>, and operator<<, or you could
> > > > select "arithmetic<big_endian>" "input<native> output<native>", or
> some
> > > > combination of these. and it would do it that way instead.  It would
> rely
> > > on
> > > > a compiler to optimize all the inline operators away. The library code
> > > would
> > > > be fairly complex, but the usage would be simple, just replace the
> types
> > > and
> > > > specify the usage.  Addition of new formats would be done with the
> > > addition
> > > > of new traits templates. With a good design it would be a linear
> increase
> > > in
> > > > code, not an exponential one.
> > > >
> > > >   -gary-
> > > >
> > > > gary.powell_at_[hidden]
> > > >
> > > >
> > > >
> > > >
> > >
> > >
> > >
> > >
> > >
> >
> >
> >
> >
> 
> 
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> 
>