Re: [Libclc-developers] Re: contribution(?): string function ultostr()

[Michael B.A. <mb...@io...>]

On Mon, 17 Mar 2003 17:56:05 +0100 (MET)
Jan Engelhardt <je...@li...> wrote:

> >> /*=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D
> >> ultostr
> >>   by Jan "Hirogen2" Engelhardt <hirogen2 at gmx de>, 2003
> >>   -- distributed under the Frontier Artistic License and GNU General P=
ublic
> >>   -- License. See doc/FAL1.txt and doc/GPL2.txt for details.
> >
> >The license must be changed to BSD.
> What's the thing about BSD?

http://www.opensource.org/licenses/bsd-license.php

> >> SYNOPSIS
> >>     unsigned char *ultostr(unsigned long num, unsigned long base,
> >>      unsigned char *ptr, size_t size);
> >unsigned long base is pretty long for the range 2..36 :-) strtoul uses
> >int for base.
> woho... heh right, that probably should have been unsigned char.

If you were very space conscientious that would indeed be the correct
datatype. However I think I would use strtoul as a guide here and just
use int.

> >Unsigned char* are very uncommon in C libraries, and its buddy function
> >strtoul uses char*.
> And? I like it. It's probably because I cannot feel comfortable when they
> assign the '=F6' a value of -10.

Functions that take char * for historical reasons will take care to
properly convert each character as necessary taking into consideration
what the locale encoding is. Using unsigned char * is appropriate
for encoding and decoding types of function however in this context
considering we're only expecting ASCII character coupled with the fact
that again strtoul should probably be used as a model I suggest char *.

So just:

char *
clc_ultostr(unsigned long num, int base, char *ptr, size_t size)
{
...

> The major aspects of my style are
>=20
> >unsigned char *ultostr(
> >     unsigned long num,
> >     unsigned long base,
> >     unsigned char *ptr,
> >     size_t size)
> - one row, or indent-by-1 if longer than 79 chars

Sounds good here too.

>=20
> >{
> - as well as keeping any { on the line

The prevailing technique is to place the bracket on a new line I
believe. Some editors actually key on these (vi for one).

> >     unsigned char *sym =3D "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ",
> >
> >     clc_assert_not_null(ultostr, ptr);
> >     clc_assert_arg(ultostr, base >=3D 2 && base <=3D 36);
> >
> >     *startp =3D ptr + size - 2;

What would happen if size were 2, 1, or even 0? Those are legitimate
values.

> >     if(base < 2 || base > 36) {
> >         errno =3D ERANGE;
> >         return NULL;
> >     }
> >
> >     while(--size > 0) {

If size were originally 0 size would rollover to a vary high number.

> >         *ptr =3D sym[num % base];
> >         num /=3D base;
> >         --ptr;
> >    }

What about negative values?

Mike

--=20
A  program should be written to model the concepts of the task it
performs rather than the physical world or a process because this
maximizes  the  potential  for it to be applied to tasks that are
conceptually  similar and, more important, to tasks that have not
yet been conceived.=20