BLParam.hh

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//      Param.hh
/*
This source file is part of G4beamline, http://g4beamline.muonsinc.com
Copyright (C) 2003,2004,2005,2006 by Tom Roberts, 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.

http://www.gnu.org/copyleft/gpl.html
*/

#ifndef BLPARAM_HH
#define BLPARAM_HH

#include <math.h>
#include "globals.hh"
#include "G4Types.hh"
#include "BLCommand.hh"

/**     BLParam - parameter class
 *
 *      The global object Param is used to access parameter values defined
 *      via the param command. The param command and the setParam()
 *      functions create parameter name/value pairs known to the Param object.
 *
 *      The BLSetParam class can be used to set initial values of parameters.
 *
 *      The internal representation of every value is a G4String, but that
 *      can be converted to double or int via get...() functions.
 *
 *      NOTE: the get*() functions are intended to be used during 
 *      initialization, not during tracking. They perform a format conversion
 *      and can be expensive -- a single call to getDouble() in
 *      UserSteppingAction() slowed tracking down by MORE THAN A FACTOR OF TEN!
 *
 *      NOTE: static and global constructors CAN use Param; this is
 *      explicitly allowed because init() guarantees initialization order.
 **/
class BLParam {
        static std::map<G4String,G4String> *paramMap;
        static std::map<G4String,G4String> *paramHelpText;
        static void init();
public:
        /// Constructor. 
        BLParam() { init(); }

        /// printParam() will display all defined parameters on stdout.
        void printParam();

        /// getString() returns the G4String value of a parameter.
        /// If name is not defined as a parameter, the environment is searched.
        /// Returns "" for unknown parameters, and displays the error on stdout.
        /// DO NOT USE DURING TRACKING!
        G4String getString(G4String name);

        /// getDouble() returns the G4double value of a parameter.
        /// returns -HUGE_VAL for unknown or invalid-format parameters,
        /// and displays the error on stdout.
        /// DO NOT USE DURING TRACKING!
        G4double getDouble(G4String name);

        /// getInt() returns the G4int value of a parameter.
        /// returns 0x80000000 for unknown or invalid-format parameters, and
        /// displays the error on stdout.
        /// DO NOT USE DURING TRACKING!
        G4int getInt(G4String name);

        /// setParam() sets the value of a parameter.
        /// DO NOT USE DURING TRACKING!
        void setParam(G4String name, G4String value);

        /// setParam() sets the value of a parameter.
        /// DO NOT USE DURING TRACKING!
        void setParam(G4String name, G4double value);

        /// setParam() sets the value of a parameter.
        /// DO NOT USE DURING TRACKING!
        void setParam(G4String name, G4int value);

        /// isDefined() returns true if the name has a defined value.
        bool isDefined(G4String name);

        /// expand() will expand every $name in str with parameter values.
        /// DO NOT USE DURING TRACKING!
        G4String expand(G4String str);

        /// setHelpText() will set help text for a parameter
        /// DO NOT USE DURING TRACKING!
        void setHelpText(G4String name, G4String text);

        /// getHelpText() returns the (complete) help text string.
        /// DO NOT USE DURING TRACKING!
        G4String getHelpText();
};

extern BLParam Param;   /// the global Param object

/**     class BLSetParam -- Parameter initialization class
 *
 *      Classes that use Parameters should declare a static instance of
 *      this class to provide a default value for each such parameter.
 *      Take care that the value is of the proper format.
 *
 *      These values are set initally, so "param -unset" will not set them.
 **/
class BLSetParam {
public:
        BLSetParam(G4String name, G4String value, G4String helpText="")
                { Param.setParam(name,value); 
                  if(helpText.size() > 0) Param.setHelpText(name,helpText);
                }
};

#endif // BLPARAM_HH