libi2ncommon: (gerd) initial submission, not in use yet

[libi2ncommon] / src / pipestream.hxx

/***************************************************************************
              inpipestream.hxx  -  C++ streambuffer wrapper 
                             -------------------
    begin                : Thu Dec 27 2001
    copyright            : (C) 2001 by Intra2net AG
    email                : intranator@intra2net.com
 ***************************************************************************/

#ifndef _PIPESTREAM
#define _PIPESTREAM

#include <string>
#include <streambuf>
#include <cstdio>

#include "exception.hxx"

// ATTENTION: A lot of mysterious STL bugs occured
//            with a "real" buffer (buffer larger than 1 byte and up to 100 bytes)
//            -> Keep it slow and working!

class inpipebuf : public std::streambuf
{
   protected:
   char buffer;
   FILE *pipe;

   public:
   inpipebuf(const std::string& command)
   {
      pipe = popen (command.c_str(), "r");
      if (pipe == NULL)
         throw EXCEPTION (pipestream_error, "can't open program or permission denied");

      // force underflow
      setg (&buffer, &buffer, &buffer);
   }

   ~inpipebuf()
   {
      if (pipe != NULL)
         pclose (pipe);

      pipe = NULL;
   }

   protected:
   virtual int_type underflow()
   {
      if (gptr() < egptr())
         return traits_type::to_int_type(*gptr());

      buffer = fgetc (pipe);
      if (feof (pipe))
      {
         // ERROR or EOF
         return EOF;
      }

      setg (&buffer, &buffer, &buffer+sizeof(char));

      return traits_type::to_int_type(*gptr());
   }
}; 

class inpipestream : public std::istream
{
   protected:
      inpipebuf buf;
   public:
      inpipestream(const std::string& command)
         : buf(command), std::istream(&buf)
         {}
};

class outpipebuf : public std::streambuf
{
   protected:
   FILE *pipe;

   public:
   outpipebuf(const std::string& command)
   {
      pipe = popen (command.c_str(), "w");
      if (pipe == NULL)
         throw EXCEPTION (pipestream_error, "can't open program or permission denied");
   }

   ~outpipebuf()
   {
      if (pipe != NULL)
         pclose (pipe);

      pipe = NULL;
   }

   protected:
   virtual int_type overflow(int_type c)
   {
      if (c != EOF)
      {
         if (fputc(c,pipe)==EOF)
            return EOF;
      }
      return c;
   }

   virtual std::streamsize xsputn(const char* s, std::streamsize num)
   {
      return fwrite(s,num,1,pipe);
   }
};

class outpipestream : public std::ostream
{
   protected:
      outpipebuf buf;
   public:
      outpipestream(const std::string& command)
         : buf(command), std::ostream(&buf)
         {}
};

#endif