107 lines
3.0 KiB
C++
107 lines
3.0 KiB
C++
//========= Copyright Valve Corporation, All rights reserved. ============//
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//
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// The expression operator class - scalar math calculator
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// for a good list of operators and simple functions, see:
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// \\fileserver\user\MarcS\boxweb\aliveDistLite\v4.2.0\doc\alive\functions.txt
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// (although we'll want to implement elerp as the standard 3x^2 - 2x^3 with rescale)
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//
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//=============================================================================
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#ifndef DMEEXPRESSIONOPERATOR_H
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#define DMEEXPRESSIONOPERATOR_H
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#ifdef _WIN32
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#pragma once
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#endif
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#include "movieobjects/dmeoperator.h"
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#include "tier1/utlstack.h" // for calculator
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#include "tier1/utlvector.h" // for calculator
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//-----------------------------------------------------------------------------
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// Calculator Parsing class
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// precedence order:
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// unary operators: + - ! func var
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// * / %
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// + -
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// < > <= >=
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// == !=
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// &&
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// ||
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// ?:
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//-----------------------------------------------------------------------------
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class CExpressionCalculator
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{
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public:
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CExpressionCalculator( const char *expr = NULL ) : m_expr( expr ) {}
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void SetExpression( const char *expr )
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{
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m_expr = expr;
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}
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void SetVariable( const char *var, float value );
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void SetVariable( int nVariableIndex, float value );
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int FindVariableIndex( const char *var );
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bool Evaluate( float &value );
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// Builds a list of variable names from the expression
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bool BuildVariableListFromExpression( );
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// Iterate over variables
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int VariableCount();
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const char *VariableName( int nIndex );
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private:
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bool ParseExpr ( const char *&expr );
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bool ParseConditional( const char *&expr );
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bool ParseOr ( const char *&expr );
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bool ParseAnd ( const char *&expr );
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bool ParseEquality ( const char *&expr );
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bool ParseLessGreater( const char *&expr );
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bool ParseAddSub ( const char *&expr );
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bool ParseDivMul ( const char *&expr );
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bool ParseUnary ( const char *&expr );
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bool ParsePrimary ( const char *&expr );
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bool Parse1ArgFunc ( const char *&expr );
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bool Parse2ArgFunc ( const char *&expr );
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bool Parse3ArgFunc ( const char *&expr );
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// bool Parse4ArgFunc ( const char *&expr );
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bool Parse5ArgFunc ( const char *&expr );
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CUtlString m_expr;
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CUtlVector< CUtlString > m_varNames;
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CUtlVector<float> m_varValues;
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CUtlStack<float> m_stack;
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bool m_bIsBuildingArgumentList;
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};
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//-----------------------------------------------------------------------------
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// An operator which computes the value of expressions
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//-----------------------------------------------------------------------------
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class CDmeExpressionOperator : public CDmeOperator
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{
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DEFINE_ELEMENT( CDmeExpressionOperator, CDmeOperator );
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public:
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virtual void Operate();
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virtual void GetInputAttributes ( CUtlVector< CDmAttribute * > &attrs );
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virtual void GetOutputAttributes( CUtlVector< CDmAttribute * > &attrs );
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void SetSpewResult( bool state );
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protected:
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bool Parse( const char *expr );
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bool IsInputAttribute( CDmAttribute *pAttribute );
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CDmaVar< float > m_result;
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CDmaString m_expr;
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CDmaVar< bool > m_bSpewResult;
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};
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#endif // DMEEXPRESSIONOPERATOR_H
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