Re: strstream reinstatement

In article <1157636428.873405.22210@m79g2000cwm.googlegroups.com>,
werasm <w_erasm@telkomsa.net> wrote:


 ... memory based stream buffers....

   A lot of the excess copying can be avoid by being less terse,by
using a default constructed stringstream and copying with
an ostreambuf_iterator<char> to the stream and then seeking the
beginning read [seekg(0)] and then reading the stream.

prepending an ostream can be read into a properly sized char array
or vector<char> via std::copy(std::istreambuf_iterator<char>
(stream),...);

   std::ostringstream os;
   // write to os
   foo(os.str().c_str()); // ouch two copies of data

   std::stringstream os;
   // write to os;
   {
      std::vector<char> tmp(std::istreambuf_iterator<char>(os),
         std::std::istream_iterator<char>()); // one copy of data
      tmp.push_back('\0');
      foo(&*tmp.begin());
   }

   initializing a string stream form a '\0' terming terminated char
array does not need to be converted to a string first, since something
like
      std::istringstream in("20 10");
      // read the stream

   can be done with
      std::stringstream in;
      {
         char *p = "20 10";
         std::ostreambuf_iterator<char> out(in);
         while (*p)
            *out++ = *p++;
         in.seekg();
      }
      // read the stream.
note this does no unnecessary conversions to std::string.

seems like the only thing is simple usages that can be handled simple
stream buffers that don't seek, if you don't seek the stream
[seekp,seekp] then the streambuf's defaults [always fail] will work.
so only thing needed is a constructor to set the buffer and end()
function for output only memory buf

   struct isimplemembuf:std::streambuf
   {
      isimplemembuf(char *start,std::ptrdiff_t size)
      {setg(start,start,start+size}
      char *begin() {return eback();}
      char *end() {return egptr();}
   };

    struct osimplemembuf:std::streambuf
   {
      osimplemembuf(char *start,std::ptrdiff_t size)
      { setp(start,start+size);}
      char *begin() {return pbase();}
      char *end() {return pptr();}
   };

look simple enough:)
    The seekpos and seekoff functions can be written if needed.
Tedious but not complicated...

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