/*
 *  ZThreads, a platform-independant, multithreading and 
 *  synchroniation library
 *
 *  Copyright (C) 2001, 2002 Eric Crahen, See LGPL.TXT for details
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library 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
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 *  SUNY @ Buffalo, hereby disclaims all copyright interest in the
 *  ZThreads library written by Eric Crahen
 */

#ifndef __ZTTSS_H__
#define __ZTTSS_H__

#include <windows.h>

namespace ZThread {

/**
 * @class TSS
 * @author Eric Crahen <crahen@cse.buffalo.edu>
 * @date <2002-05-26T11:47:55-0400>
 * @version 2.1.0
 *
 * An abstraction for dealing with WIN32 thread specific storage (tss). 
 * Provides get/set and creation/destruction.
 */
template <typename T>
class TSS {
  
  DWORD _key;
  bool _valid;

 public:

  /**
   * Create a new object for accessing tss. The def
   */
  TSS() throw() {

    _key = ::TlsAlloc();
    _valid = (_key != 0xFFFFFFFF);

  }

 /**
  * Destroy the underlying supoprt for accessing tss with this 
  * object.
  */
 virtual ~TSS() throw() {
  
   if(_valid) 
     ::TlsFree(_key);
   
 }
 
 /**
  * Get the value stored in tss.
  *
  * @return T
  *
  * @exception InvalidOp_exception thrown when the tss is not properly initialized
  */
 inline T get() const throw() {

  if(!_valid)
    throw InvalidOp_Exception();

  return static_cast<T>(::TlsGetValue(_key));

}

 /**
  * Store a value in tss.
  *
  * @param value T
  * @return T old value
  *
  * @exception InvalidOp_exception thrown when the tss is not properly initialized
  */
 inline T set(T value) const throw() {

  T oldValue = get();
  ::TlsSetValue(_key, value);

  return oldValue;

 }
 
 
};

};

#endif


