parsedFunction.h

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// -*- Mode: C++; tab-width: 2; -*-
// vi: set ts=2:
//

#ifndef BALL_MATHS_PARSEDFUNCTION_H
#define BALL_MATHS_PARSEDFUNCTION_H

#ifndef BALL_DATATYPE_STRINGHASHMAP_H
# include <BALL/DATATYPE/stringHashMap.h>
#endif

#include <numeric>

using std::unary_function;

extern double ParsedFunctionResult;
extern int ParsedFunctionparse();
extern void ParsedFunction_initBuffer(const char*);
extern void ParsedFunction_delBuffer();

namespace BALL
{
  extern StringHashMap<double*> *ParsedFunctionConstants;
  extern StringHashMap<double (*)(double)> *ParsedFunctionFunctions;
  
  template <typename arg> 
  class ParsedFunction 
    : public unary_function<arg, double> 
  {
    public:
  
      ParsedFunction();
  
      ParsedFunction(const String& expression);
      
      ParsedFunction(const ParsedFunction& func);
      
      ~ParsedFunction();
      
      
      double operator () (arg p);
    

      void initTable();
  
      StringHashMap<double*> constants_;
  
      StringHashMap<double (*)(double)> functions_;
    
    protected:
      String expression_;
  };

  template <typename arg>
  ParsedFunction<arg>::ParsedFunction()
    : constants_(),
      functions_(),
      expression_("")
  {
    initTable();
  }

  template <typename arg>
  ParsedFunction<arg>::ParsedFunction(const String& expression)
    : constants_(),
      functions_(),
      expression_(expression)
  {
    initTable();
  }
  
  template <typename arg>
  ParsedFunction<arg>::ParsedFunction(const ParsedFunction& func) 
  {
    constants_ = func.constants_;
    functions_ = func.functions_;
    expression_ = func.expression_;
    initTable();
  }

  template <typename arg>
  ParsedFunction<arg>::~ParsedFunction()
  {
  }

  template <typename arg>
  double ParsedFunction<arg>::operator () (arg argument)
  {
    constants_["X"] = (double*)&argument;
    ParsedFunctionConstants = &constants_;
    ParsedFunctionFunctions = &functions_;
    ParsedFunction_initBuffer(expression_.c_str());
    ParsedFunctionparse();
    ParsedFunction_delBuffer();
    
    return ParsedFunctionResult;
  }

  template <>
  BALL_EXPORT double ParsedFunction<float>::operator () (float argument);

  template <>
  BALL_EXPORT double ParsedFunction<double>::operator () (double argument);
 
  template <typename arg>
  void ParsedFunction<arg>::initTable()
  {
    // initialize the functions table
    functions_["sin"] = (double(*)(double))&sin;
    functions_["cos"] = (double(*)(double))&cos;
    functions_["asin"] = (double(*)(double))&asin;
    functions_["acos"] = (double(*)(double))&acos;
    functions_["tan"] = (double(*)(double))&tan;
    functions_["atan"] = (double(*)(double))&atan;
    functions_["ln"] = (double(*)(double))&log;
    functions_["exp"] = (double(*)(double))&exp;
    functions_[""] = 0;
  }

}

#endif // BALL_MATHS_PARSEDFUNCTION_H

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