/*
 * Copyright (c) 1996 Gunther Schadow.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#ifndef _FDSET_H
#define _FDSET_H

#pragma interface

#include <sys/types.h>
#include <string.h>

/*
  A simple C++ wrapper for fd_set used with select(2) calls. An fd_set
  is a set of file descriptors. The class FdSet inherits from struct
  fd_set (BSD declares the fd_set as a struct, I hope that there is a
  common agreement on this practice (POSIX?)). Thus an FdSet* can be
  directly used whereever an fd_set* is required, although most (all?)
  standard fd_set functions can be called as methods of class FdSet.
*/

class FdSet: public fd_set
{
 public:
       FdSet()       { FD_ZERO(this); }    // init with an empty set
       FdSet(int ...);                     // term'd by -1
  void zero ()       { FD_ZERO(this); }    // clear the set
  void set  (int fd) { FD_SET(fd, this); } // add a file descriptor
  void clear(int fd) { FD_CLR(fd, this); } // remove a file descriptor
  bool isset(int fd) { return FD_ISSET(fd, this); } // test for membership

  /*
   * iterators, return -1 if no channel left in set
   * example: for(int ch = cs.first(), ch >= 0, ch = cs.next(ch))
   */
  int  first()   const { return next(-1); }
  int  next(int) const;
  int  last()    const { return prev(-1); } // vice versa ...
  int  prev(int) const;

  int  nfds() const { return last() + 1; } // the first argument of select(2)

  // and the select(2) call variants
  int  select(FdSet *r, FdSet *w, FdSet *e, u_int sec, u_int usec) const;
  int  select(FdSet *r, FdSet *w, FdSet *e) const;

  /*
   * the default bitwise copy constructor/operator are just adequate
   * only the likewise eq-op is missing:
   */
  bool operator==(const FdSet &s) const
    { return memcmp(this, &s, sizeof(s))== 0; }
};

#endif