flightgear/src/FDM/JSBSim/FGJSBBase.h

/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

 Header:       FGJSBBase.h
 Author:       Jon S. Berndt
 Date started: 07/01/01

 ------------- Copyright (C) 2001  Jon S. Berndt (jon@jsbsim.org) -------------

 This program 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 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 Lesser General Public License for more
 details.

 You should have received a copy of the GNU Lesser General Public License along with
 this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 Place - Suite 330, Boston, MA  02111-1307, USA.

 Further information about the GNU Lesser General Public License can also be found on
 the world wide web at http://www.gnu.org.

HISTORY
--------------------------------------------------------------------------------
07/01/01  JSB  Created

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
SENTRY
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#ifndef FGJSBBASE_H
#define FGJSBBASE_H

/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
INCLUDES
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#include <float.h>
#include <queue>
#include <string>
#include <cmath>

using std::min;
using std::max;

#include "input_output/string_utilities.h"

#ifndef M_PI
#  define M_PI 3.14159265358979323846
#endif
#define IDENT(a,b)	 static const char* const (a)[] = {b,(a)[0]}

/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
DEFINITIONS
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#define ID_JSBBASE "$Id: FGJSBBase.h,v 1.41 2014/09/03 17:35:04 bcoconni Exp $"

/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
FORWARD DECLARATIONS
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namespace JSBSim {

/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
CLASS DOCUMENTATION
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/** JSBSim Base class.
*   This class provides universal constants, utility functions, messaging
*   functions, and enumerated constants to JSBSim.
    @author Jon S. Berndt
    @version $Id: FGJSBBase.h,v 1.41 2014/09/03 17:35:04 bcoconni Exp $
*/

/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
CLASS DECLARATION
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class FGJSBBase {
public:
  /// Constructor for FGJSBBase.
  FGJSBBase() {};

  /// Destructor for FGJSBBase.
  virtual ~FGJSBBase() {};

  /// JSBSim Message structure
  class Message {
  public:
    unsigned int fdmId;
    unsigned int messageId;
    std::string text;
    std::string subsystem;
    enum mType {eText, eInteger, eDouble, eBool} type;
    bool bVal;
    int  iVal;
    double dVal;
  };

  /// First order, (low pass / lag) filter
  class Filter {
    double prev_in;
    double prev_out;
    double ca;
    double cb;
    public: Filter(void) {}
    public: Filter(double coeff, double dt) {
      prev_in = prev_out = 0.0;
      double denom = 2.0 + coeff*dt;
      ca = coeff*dt/denom;
      cb = (2.0 - coeff*dt)/denom;
    }
    public: double execute(double in) {
      double out = (in + prev_in)*ca + prev_out*cb;
      prev_in = in;
      prev_out = out;
      return out;
    }
  };

  ///@name JSBSim console output highlighting terms.
  //@{
  /// highlights text
  static char highint[5];
  /// low intensity text
  static char halfint[5];
  /// normal intensity text
  static char normint[6];
  /// resets text properties
  static char reset[5];
  /// underlines text
  static char underon[5];
  /// underline off
  static char underoff[6];
  /// blue text
  static char fgblue[6];
  /// cyan text
  static char fgcyan[6];
  /// red text
  static char fgred[6];
  /// green text
  static char fggreen[6];
  /// default text
  static char fgdef[6];
  //@}

  ///@name JSBSim Messaging functions
  //@{
  /** Places a Message structure on the Message queue.
      @param msg pointer to a Message structure
      @return pointer to a Message structure */
  void PutMessage(const Message& msg);
  /** Creates a message with the given text and places it on the queue.
      @param text message text
      @return pointer to a Message structure */
  void PutMessage(const std::string& text);
  /** Creates a message with the given text and boolean value and places it on the queue.
      @param text message text
      @param bVal boolean value associated with the message
      @return pointer to a Message structure */
  void PutMessage(const std::string& text, bool bVal);
  /** Creates a message with the given text and integer value and places it on the queue.
      @param text message text
      @param iVal integer value associated with the message
      @return pointer to a Message structure */
  void PutMessage(const std::string& text, int iVal);
  /** Creates a message with the given text and double value and places it on the queue.
      @param text message text
      @param dVal double value associated with the message
      @return pointer to a Message structure */
  void PutMessage(const std::string& text, double dVal);
  /** Reads the message on the queue (but does not delete it).
      @return 1 if some messages */
  int SomeMessages(void);
  /** Reads the message on the queue and removes it from the queue.
      This function also prints out the message.*/
  void ProcessMessage(void);
  /** Reads the next message on the queue and removes it from the queue.
      This function also prints out the message.
      @return a pointer to the message, or NULL if there are no messages.*/
  Message* ProcessNextMessage(void);
  //@}

  /** Returns the version number of JSBSim.
  *   @return The version number of JSBSim. */
  std::string GetVersion(void) {return JSBSim_version;}

  /// Disables highlighting in the console output.
  void disableHighLighting(void);

  static short debug_lvl;

  /** Converts from degrees Kelvin to degrees Fahrenheit.
  *   @param kelvin The temperature in degrees Kelvin.
  *   @return The temperature in Fahrenheit. */
  static double KelvinToFahrenheit (double kelvin) {
    return 1.8*kelvin - 459.4;
  }

  /** Converts from degrees Celsius to degrees Rankine.
  *   @param celsius The temperature in degrees Celsius.
  *   @return The temperature in Rankine. */
  static double CelsiusToRankine (double celsius) {
    return celsius * 1.8 + 491.67;
  }

  /** Converts from degrees Rankine to degrees Celsius.
  *   @param rankine The temperature in degrees Rankine.
  *   @return The temperature in Celsius. */
  static double RankineToCelsius (double rankine) {
    return (rankine - 491.67)/1.8;
  }

  /** Converts from degrees Kelvin to degrees Rankine.
  *   @param kelvin The temperature in degrees Kelvin.
  *   @return The temperature in Rankine. */
  static double KelvinToRankine (double kelvin) {
    return kelvin * 1.8;
  }

  /** Converts from degrees Rankine to degrees Kelvin.
  *   @param rankine The temperature in degrees Rankine.
  *   @return The temperature in Kelvin. */
  static double RankineToKelvin (double rankine) {
    return rankine/1.8;
  }

  /** Converts from degrees Fahrenheit to degrees Celsius.
  *   @param fahrenheit The temperature in degrees Fahrenheit.
  *   @return The temperature in Celsius. */
  static double FahrenheitToCelsius (double fahrenheit) {
    return (fahrenheit - 32.0)/1.8;
  }

  /** Converts from degrees Celsius to degrees Fahrenheit.
  *   @param celsius The temperature in degrees Celsius.
  *   @return The temperature in Fahrenheit. */
  static double CelsiusToFahrenheit (double celsius) {
    return celsius * 1.8 + 32.0;
  }

  /** Converts from degrees Celsius to degrees Kelvin
  *   @param celsius The temperature in degrees Celsius.
  *   @return The temperature in Kelvin. */
  static double CelsiusToKelvin (double celsius) {
    return celsius + 273.15;
  }

  /** Converts from degrees Kelvin to degrees Celsius
  *   @param celsius The temperature in degrees Kelvin.
  *   @return The temperature in Celsius. */
  static double KelvinToCelsius (double kelvin) {
    return kelvin - 273.15;
  }

  /** Converts from feet to meters
  *   @param measure The length in feet.
  *   @return The length in meters. */
  static double FeetToMeters (double measure) {
    return measure*0.3048;
  }

  /** Calculate the calibrated airspeed from the Mach number. It uses the
  *   Rayleigh formula for supersonic speeds (See "Introduction to Aerodynamics
  *   of a Compressible Fluid - H.W. Liepmann, A.E. Puckett - Wiley & sons
  *   (1947)" §5.4 pp 75-80)
  *   @param mach  The Mach number
  *   @param p     Pressure in psf
  *   @param psl   Pressure at sea level in psf
  *   @param rhosl Density at sea level in slugs/ft^3
  *   @return The calibrated airspeed (CAS) in ft/s
  * */
  static double VcalibratedFromMach(double mach, double p, double psl, double rhosl);

  /** Calculate the Mach number from the calibrated airspeed. For subsonic
  * speeds, the reversed formula has a closed form. For supersonic speeds, the
  * Rayleigh formula is reversed by the Newton-Raphson algorithm.
  *   @param vcas  The calibrated airspeed (CAS) in ft/s
  *   @param p     Pressure in psf
  *   @param psl   Pressure at sea level in psf
  *   @param rhosl Density at sea level in slugs/ft^3
  *   @return The Mach number
  * */
  static double MachFromVcalibrated(double vcas, double p, double psl, double rhosl);

  /** Finite precision comparison.
      @param a first value to compare
      @param b second value to compare
      @return if the two values can be considered equal up to roundoff */
  static bool EqualToRoundoff(double a, double b) {
    double eps = 2.0*DBL_EPSILON;
    return std::fabs(a - b) <= eps * max(std::fabs(a), std::fabs(b));
  }

  /** Finite precision comparison.
      @param a first value to compare
      @param b second value to compare
      @return if the two values can be considered equal up to roundoff */
  static bool EqualToRoundoff(float a, float b) {
    float eps = 2.0*FLT_EPSILON;
    return std::fabs(a - b) <= eps * max(std::fabs(a), std::fabs(b));
  }

  /** Finite precision comparison.
      @param a first value to compare
      @param b second value to compare
      @return if the two values can be considered equal up to roundoff */
  static bool EqualToRoundoff(float a, double b) {
    return EqualToRoundoff(a, (float)b);
  }

  /** Finite precision comparison.
      @param a first value to compare
      @param b second value to compare
      @return if the two values can be considered equal up to roundoff */
  static bool EqualToRoundoff(double a, float b) {
    return EqualToRoundoff((float)a, b);
  }
  
  /** Constrain a value between a minimum and a maximum value.
  */
  static double Constrain(double min, double value, double max) {
    return value<min?(min):(value>max?(max):(value));
  }
  
  static double sign(double num) {return num>=0.0?1.0:-1.0;}

  static double GaussianRandomNumber(void);

protected:
  static Message localMsg;

  static std::queue <Message> Messages;

  void Debug(int) {};

  static unsigned int messageId;

  static const double radtodeg;
  static const double degtorad;
  static const double hptoftlbssec;
  static const double psftoinhg;
  static const double psftopa;
  static const double fpstokts;
  static const double ktstofps;
  static const double inchtoft;
  static const double in3tom3;
  static const double m3toft3;
  static const double inhgtopa;
  static const double fttom;
  static double Reng;         // Specific Gas Constant,ft^2/(sec^2*R)
  static double Rstar;
  static double Mair;
  static const double SHRatio;
  static const double lbtoslug;
  static const double slugtolb;
  static const double kgtolb;
  static const double kgtoslug;
  static const std::string needed_cfg_version;
  static const std::string JSBSim_version;

  static std::string CreateIndexedPropertyName(const std::string& Property, int index);

  static int gaussian_random_number_phase;

public:
/// Moments L, M, N
enum {eL     = 1, eM,     eN    };
/// Rates P, Q, R
enum {eP     = 1, eQ,     eR    };
/// Velocities U, V, W
enum {eU     = 1, eV,     eW    };
/// Positions X, Y, Z
enum {eX     = 1, eY,     eZ    };
/// Euler angles Phi, Theta, Psi
enum {ePhi   = 1, eTht,   ePsi  };
/// Stability axis forces, Drag, Side force, Lift
enum {eDrag  = 1, eSide,  eLift };
/// Local frame orientation Roll, Pitch, Yaw
enum {eRoll  = 1, ePitch, eYaw  };
/// Local frame position North, East, Down
enum {eNorth = 1, eEast,  eDown };
/// Locations Radius, Latitude, Longitude
enum {eLat = 1, eLong, eRad     };
/// Conversion specifiers
enum {inNone = 0, inDegrees, inRadians, inMeters, inFeet };

};

}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
#endif