File indexing completed on 2024-04-21 03:42:10

 /*
     KmPlot - a math. function plotter for the KDE-Desktop
 
     SPDX-FileCopyrightText: 1998, 1999, 2000, 2002 Klaus-Dieter Möller <kd.moeller@t-online.de>
     SPDX-FileCopyrightText: 2006 David Saxton <david@bluehaze.org>
 
     This file is part of the KDE Project.
     KmPlot is part of the KDE-EDU Project.
 
     SPDX-License-Identifier: GPL-2.0-or-later
 
 */
 
 /** @file parser.h
  * \brief Contains the parser core class Parser. */
 
 #ifndef parser_included
 #define parser_included
 
 #include <QMap>
 #include <QObject>
 #include <QVector>
 
 #include "constants.h"
 #include "function.h"
 #include "vector.h"
 
 // Various mathematical symbols
 #define PiSymbol QChar(0x3c0)
 #define InfinitySymbol QChar(0x221e)
 #define PmSymbol QChar(0xb1)
 #define AbsSymbol QChar(0x2223)
 #define SqrtSymbol QChar(0x221a)
 #define MinusSymbol QChar(0x2212)
 #define SubscriptZeroSymbol QChar(0x2080)
 #define GeSymbol QChar(0x2265)
 #define LeSymbol QChar(0x2264)
 
 class Parser;
 
 // Voreinstellungen bei Verwendung des Standardkonstruktors :
 
 #define STACKSIZE 1000 ///< stack depth
 
 //@{
 /** Token type. */
 enum Token {
     KONST, //  0 - double value follows
     VAR, //  1 - get a parameter (e.g. x or k)
     PUSH, //  2 - push value to stack
     PLUS, //  3 - add
     MINUS, //  4 - subtract
     PM, //  5 - plus-minus; add or subtract depending on the current signature
     MULT, //  6 - multiply
     DIV, //  7 - divide
     POW, //  8 - exponentiate
     NEG, //  9 - negate
     FKT_1, // 10 - address to function with 1 argument follows
     FKT_N, // 11 - address to functions with an indefinite number of arguments follows
     UFKT, // 12 - address to user defined function follows
     SQRT, // 13 - take square root
     FACT, // 14 - take factorial
     GT, // 15 - greater than
     GE, // 16 - greater than or equal
     LT, // 17 - less than
     LE, // 18 - less than or equal
     ENDE, // 19 - end of function
     ERROR // 20 - error in function
 };
 
 const int legendreCount = 7; // number of legendre polynomials we allow for
 const int ScalarCount = 40 + legendreCount; // number of mathematical scalar functions
 const int VectorCount = 3; // number of vector functions
 //@}
 
 //@{
 /** Predefined mathematical function with one variable. */
 double sign(double x);
 double heaviside(double x);
 double sqr(double x);
 
 double lsec(double x);
 double lcosec(double x);
 double lcot(double x);
 double larcsec(double x);
 double larccosec(double x);
 double larccot(double x);
 
 double sech(double x);
 double cosech(double x);
 double coth(double x);
 double arsech(double x);
 double arcosech(double x);
 double arcoth(double x);
 
 double lcos(double x);
 double lsin(double x);
 double ltan(double x);
 
 double larccos(double x);
 double larcsin(double x);
 double larctan(double x);
 
 double legendre0(double x);
 double legendre1(double x);
 double legendre2(double x);
 double legendre3(double x);
 double legendre4(double x);
 double legendre5(double x);
 double legendre6(double x);
 
 double factorial(double x);
 double lerf(double x);
 double lerfc(double x);
 
 /** Predefined mathematical functions with an indefinite number of variables. */
 double min(const Vector &x);
 double max(const Vector &x);
 double mod(const Vector &x);
 
 struct ScalarFunction {
     QString name1;
     QString name2;
     double (*mfadr)(double);
 };
 
 struct VectorFunction {
     QString name;
     double (*mfadr)(const Vector &);
 };
 
 /**
  * Fixes user-entered expressions into a form that can be handled by the
  * parser. Also keeps track of how the string was modified, so that if an error
  * occurs, then the correct position can be reported to the user.
  * \note The convention used here is that the first letter in a string
  * is at position zero.
  */
 class ExpressionSanitizer
 {
 public:
     explicit ExpressionSanitizer(Parser *parent);
 
     /**
      * Lots of changes to make it happy for the parser (e.g. adding extra
      * *-characters, remove spaces, replace the locale .-character with '.',
      * etc). This function will initialize m_evalMap.
      * \param str The string to be fixed.
      */
     void fixExpression(QString *str);
     /**
      * \return the position in the input string (as given to fixExpression)
      * that corresponds to the outputted string.
      */
     int realPos(int evalPos);
 
 protected:
     /**
      * Maps the position of the string returned by fixExpression to that
      * passed to it. This is so that if the parser comes across an error in the
      * sanitized expression, this gives the corresponding position in the user
      * string.
      */
     QVector<int> m_map;
 
     void remove(const QString &str);
     void remove(const QChar &str);
     void replace(QChar before, QChar after);
     void replace(QChar before, const QString &after);
     void replace(int pos, int len, const QString &after);
     void replace(const QString &before, const QString &after);
     void insert(int i, QChar ch);
     void append(QChar str);
     void stripWhiteSpace();
 
     /**
      * Prints the map and str to stdout; for debugging purposes.
      */
     void displayMap();
 
     QString *m_str;
 
     QString m_decimalSymbol;
     Parser *m_parser;
 };
 
 /** @short Parser.
  *
  * Tokenizes a function equation to be evaluated.
  */
 class Parser : public QObject
 {
     Q_OBJECT
 public:
     enum Error {
         ParseSuccess,
         SyntaxError,
         MissingBracket,
         StackOverflow,
         FunctionNameReused, ///< function name already used
         RecursiveFunctionCall,
         EmptyFunction,
         NoSuchFunction,
         ZeroOrder, ///< zero-order differential
         TooManyPM, ///< too many plus-minus symbols
         InvalidPM, ///< Not allowed to have a plus-minus symbol, e.g. in a constant expression
         TooManyArguments, ///< Too many arguments in a function, e.g. "f(x,a,b,c)"
         IncorrectArgumentCount ///< wrong number of arguments being passed to a function
     };
 
     ~Parser();
 
     /**
      * \param includeAliases whether to return function aliases (e.g.
      * arsinh for arcsinh).
      * \return the list of predefined function names.
      */
     QStringList predefinedFunctions(bool includeAliases) const;
     /**
      * \return the list of user defined function names.
      */
     QStringList userFunctions() const;
     /**
      * @return A string that is safe to use as a number in a string to be
      * parsed. This is needed as e.g. "1.2e-3" is not allowed (e is a
      * constant) - so cannot use the QString::number.
      */
     static QString number(double value);
     /**
      * Calls the array version of this function, after inserting the value
      * of the equation's parameter into x.
      */
     double fkt(Equation *it, double x);
     double fkt(uint id, int eq, double x);
     /**
      * Returns the result of a calculation. \p x are parameters for the
      * function (which are not necessarily all used).
      */
     double fkt(Equation *it, const Vector &x);
     /**
      * Evaluates the given expression.
      * \param str the given expression.
      * \param error if non-null, then will be set to the parser error (or
      * ParserSuccess if no errors).
      * \param errorPosition will be set to the position of the error (if
      * there is one).
      */
     double eval(const QString &str, Error *error = nullptr, int *errorPosition = nullptr);
     /**
      * Adds a user defined function with the given equation. The new
      * function's ID-number is returned. \p force is used to force use of
      * \p str1, \p str2, even if they cannot be parsed.
      */
     int addFunction(const QString &str1, const QString &str2, Function::Type type, bool force = false);
     /**
      * Removes the function with the given id.
      */
     bool removeFunction(uint id);
     bool removeFunction(Function *item);
     /**
      * Removes all functions.
      */
     void removeAllFunctions();
     /**
      * Returns the ID-number of the function "name". If the function
      * couldn't be found, -1 is returned.
      */
     int fnameToID(const QString &name);
     /**
      * \return An error string appropriate for the given error.
      */
     static QString errorString(Error error);
     /**
      * Displays an error dialog appropriate to \p error.
      */
     void displayErrorDialog(Error error);
     /**
      * \return the number of radians per angle-unit that the user has
      * selected (i.e. this will return 1.0 if the user has selected
      * radians; and PI/180 if the user has selected degrees).
      */
     static double radiansPerAngleUnit()
     {
         return m_radiansPerAngleUnit;
     }
 
     enum AngleMode { Radians = 0, Degrees = 1 };
     /**
      * Sets the angle mode (in which the calculations are performed).
      */
     void setAngleMode(AngleMode mode);
     /**
      * Initializes the function for evaluation. Called after the functions
      * fstr is set.
      */
     void initEquation(Equation *equation, Error *error = nullptr, int *errorPosition = nullptr);
 
     uint getNewId(); /// Returns the next ID-number
     uint countFunctions(); /// Returns how many functions there are
 
     /// The constants used by the parser
     Constants *constants() const
     {
         return m_constants;
     }
 
     /// @return the function with the given id
     Function *functionWithID(int id) const;
 
     /// Points to the array of user defined functions, index by their IDs.
     QMap<int, Function *> m_ufkt;
 
     /// Reparses all functions, e.g. for when the value of a constant changes
     void reparseAllFunctions();
 
 signals:
     /// emitted when a function is deleted
     void functionRemoved(int id);
     /// emitted when a function is added
     void functionAdded(int id);
 
 private:
     /** Mathematical function. */
     static ScalarFunction scalarFunctions[ScalarCount];
     static VectorFunction vectorFunctions[VectorCount];
 
     void heir0();
     void heir1();
     void heir2();
     void heir3();
     void heir4();
     void heir5();
     void primary();
     bool tryFunction();
     bool tryPredefinedFunction();
     bool tryUserFunction();
     bool tryVariable();
     bool tryConstant();
     bool tryNumber();
     void addToken(Token token);
     void addConstant(double);
     void adduint(uint);
     void addfptr(double (*)(double));
     void addfptr(double (*)(const Vector &), int argCount);
     /**
      * \p id Id of the function
      * \p eq_id Which equation of the function to use
      * \p args The number of variables being passed to the function
      */
     void addfptr(uint id, uint eq_id, uint args);
     /**
      * Attempts to \p string to the current evaluation text. If the text at
      * the current evaluation position is matched, then the evaluation
      * position is incremented past the length of the string and true is
      * returned. Else the evaluation position remains unchanged, and false
      * is returned.
      */
     bool match(const QString &string);
     /**
      * Continues to read the expression inside a brackets of a vector
      * function until get to the end of the argument list.
      * \return the number of arguments
      */
     int readFunctionArguments();
 
     void growEqMem(int growth);
     QByteArray *mem; ///< Pointer to the array of tokens for the current equation being parsed
     char *mptr; ///< Pointer to the next position of insertion for the parsed equation data
     double *m_stack;
     double *stkptr;
     QString m_eval;
     int m_evalPos;
     int m_nextFunctionID;
     /// @return the m_eval starting at m_evalPos
     QString evalRemaining();
     QString m_evalRemaining;
     Equation *m_currentEquation; // Pointer to the current function
     Equation *m_ownEquation; ///< used for parsing constants, etc, and ensures that m_currentEquation is never null
     static double m_radiansPerAngleUnit;
     Constants *m_constants;
     ExpressionSanitizer m_sanitizer;
     int m_pmAt; ///< When parsing an expression, which plus-minus symbol at
     Error *m_error;
 
 private:
     friend class XParser;
     friend class ExpressionSanitizer;
     Parser();
 };
 
 #endif // parser_included