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 23:11, 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