Re: "Type-safe" sprintf

Daniel =?iso-8859-1?Q?Lidstr=F6m?= <>
Thu, 8 Mar 2007 16:07:31 +0100
On Thu, 8 Mar 2007 14:53:29 +0100, Daniel Lidstr?m wrote:

Here is the implementation of my sprintf-like function.

I simplified the implementation a little bit, so that the first argument
fed to cool::sprintf has to be the format string. This is to prevent errors

cool::sprintf(buffer) % 1 % "%d";

already at compile time.

Here's the updated version:

namespace cool
   namespace detail
      template<class Char>
      class feeder
      { };

      template<class Char, std::size_t N>
      class feeder<Char[N]>
         typedef typename boost::basic_format<Char> format_type;
         typedef typename std::basic_string<Char> string_type;

         format_type format;
         Char* buffer;


         feeder(Char* b)
            : buffer(b)
         { }

            string_type result = str(format);
            if( result.size()>=N )
               throw std::logic_error("buffer overflow in sprintf");
            std::copy(result.begin(), result.end(), buffer);
            buffer[result.size()] = 0;

         //! Format string
         format_type& operator%(const Char* c)

            return format;

   template<class Source>
   typename detail::feeder<Source> sprintf(Source& buffer)
      typedef typename detail::feeder<Source> Feeder;
      return Feeder(buffer);

A: Because it messes up the order in which people normally read text.
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A: Top-posting.
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