Re: [PATCH 1/2] Introduce string_appendf/string_vappendf (Re: [RFA 4/6] Simple cleanup removals in remote.c)

[Simon Marchi <simon dot marchi at polymtl dot ca>]

On 2017-10-18 23:12, Simon Marchi wrote:
> On 2017-10-18 23:11, Simon Marchi wrote:
> > > +
> > > +/* See documentation in common-utils.h.  */
> > > +
> > > +void
> > > +string_appendf (std::string &str, const char *fmt, ...)
> > > +{
> > > +  va_list vp;
> > > +  int grow_size;
> > > +
> > > +  va_start (vp, fmt);
> > > +  grow_size = vsnprintf (NULL, 0, fmt, vp);
> > > +  va_end (vp);
> > > +
> > > +  size_t curr_size = str.size ();
> > > +  str.resize (curr_size + grow_size);
> > > +
> > > +  /* C++11 and later guarantee std::string uses contiguous memory 
> > > and
> > > +     always includes the terminating '\0'.  */
> > > +  va_start (vp, fmt);
> > > +  vsprintf (&str[curr_size], fmt, vp);
> > > +  va_end (vp);
> > > +}
> > > +
> > > +
> > > +/* See documentation in common-utils.h.  */
> > > +
> > > +void
> > > +string_vappendf (std::string &str, const char *fmt, va_list args)
> > > +{
> > > +  va_list vp;
> > > +  int grow_size;
> > > +
> > > +  va_copy (vp, args);
> > > +  grow_size = vsnprintf (NULL, 0, fmt, vp);
> > > +  va_end (vp);
> > > +
> > > +  size_t curr_size = str.size ();
> > > +  str.resize (curr_size + grow_size);
> > > +
> > > +  /* C++11 and later guarantee std::string uses contiguous memory 
> > > and
> > > +     always includes the terminating '\0'.  */
> > > +  vsprintf (&str[curr_size], fmt, args);
> > > +}
> > > +
> >
> > string_appendf can be implemented using string_vappendf, to reduce
> > duplication.  It would basically be like string_vappendf_wrapper is.
> > In the tests, we can probably just test string_appendf then.
> >
> > Unless there's a good reason for them not sharing code?
>
> Actually the same comment would apply to string_{v,}printf.
>
> Simon

Hi Pedro,

I came across a case where string_appendf would be useful, so I was 
wondering if you intended to push this patch.  If you don't have the 
time, I would be happy to take care of it, just tell me if you agree 
with my comments and I'll make the changes & push.

Simon