180 lines
4.4 KiB
C++
180 lines
4.4 KiB
C++
/**
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* \file condition.hxx
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* Declarations and inline methods for property conditions.
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* Written by David Megginson, started 2000.
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* CLO May 2003 - Split out condition specific code.
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*
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* This file is in the Public Domain, and comes with no warranty.
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*/
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#ifndef __SG_CONDITION_HXX
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#define __SG_CONDITION_HXX
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#include <simgear/debug/logstream.hxx>
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#include <simgear/props/props.hxx>
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#include <simgear/props/props_io.hxx>
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#include <simgear/structure/SGReferenced.hxx>
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////////////////////////////////////////////////////////////////////////
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// Conditions.
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////////////////////////////////////////////////////////////////////////
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/**
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* An encoded condition.
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*
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* This class encodes a single condition of some sort, possibly
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* connected with properties.
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*
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* This class should migrate to somewhere more general.
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*/
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class SGCondition : public SGReferenced
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{
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public:
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SGCondition ();
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virtual ~SGCondition ();
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virtual bool test () const = 0;
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};
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/**
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* Condition for a single property.
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*
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* This condition is true only if the property returns a boolean
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* true value.
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*/
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class SGPropertyCondition : public SGCondition
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{
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public:
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SGPropertyCondition ( SGPropertyNode *prop_root,
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const char * propname );
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virtual ~SGPropertyCondition ();
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virtual bool test () const { return _node->getBoolValue(); }
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private:
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SGConstPropertyNode_ptr _node;
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};
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/**
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* Condition for a 'not' operator.
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*
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* This condition is true only if the child condition is false.
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*/
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class SGNotCondition : public SGCondition
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{
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public:
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SGNotCondition (SGCondition * condition);
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virtual ~SGNotCondition ();
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virtual bool test () const;
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private:
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SGSharedPtr<SGCondition> _condition;
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};
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/**
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* Condition for an 'and' group.
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*
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* This condition is true only if all of the conditions
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* in the group are true.
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*/
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class SGAndCondition : public SGCondition
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{
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public:
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SGAndCondition ();
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virtual ~SGAndCondition ();
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virtual bool test () const;
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// transfer pointer ownership
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virtual void addCondition (SGCondition * condition);
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private:
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std::vector<SGSharedPtr<SGCondition> > _conditions;
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};
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/**
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* Condition for an 'or' group.
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*
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* This condition is true if at least one of the conditions in the
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* group is true.
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*/
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class SGOrCondition : public SGCondition
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{
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public:
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SGOrCondition ();
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virtual ~SGOrCondition ();
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virtual bool test () const;
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// transfer pointer ownership
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virtual void addCondition (SGCondition * condition);
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private:
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std::vector<SGSharedPtr<SGCondition> > _conditions;
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};
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/**
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* Abstract base class for property comparison conditions.
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*/
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class SGComparisonCondition : public SGCondition
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{
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public:
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enum Type {
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LESS_THAN,
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GREATER_THAN,
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EQUALS
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};
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SGComparisonCondition (Type type, bool reverse = false);
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virtual ~SGComparisonCondition ();
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virtual bool test () const;
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virtual void setLeftProperty( SGPropertyNode *prop_root,
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const char * propname );
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virtual void setRightProperty( SGPropertyNode *prop_root,
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const char * propname );
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// will make a local copy
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virtual void setRightValue (const SGPropertyNode * value);
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private:
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Type _type;
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bool _reverse;
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SGConstPropertyNode_ptr _left_property;
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SGConstPropertyNode_ptr _right_property;
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SGConstPropertyNode_ptr _right_value;
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};
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/**
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* Base class for a conditional components.
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*
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* This class manages the conditions and tests; the component should
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* invoke the test() method whenever it needs to decide whether to
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* active itself, draw itself, and so on.
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*/
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class SGConditional : public SGReferenced
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{
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public:
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SGConditional ();
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virtual ~SGConditional ();
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// transfer pointer ownership
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virtual void setCondition (SGCondition * condition);
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virtual const SGCondition * getCondition () const { return _condition; }
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virtual bool test () const;
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private:
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SGSharedPtr<SGCondition> _condition;
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};
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/**
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* Global function to make a condition out of properties.
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*
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* The top-level is always an implicit 'and' group, whatever the
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* node's name (it should usually be "condition").
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*
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* @param node The top-level condition node (usually named "condition").
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* @return A pointer to a newly-allocated condition; it is the
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* responsibility of the caller to delete the condition when
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* it is no longer needed.
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*/
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SGCondition *sgReadCondition( SGPropertyNode *prop_root,
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const SGPropertyNode *node );
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#endif // __SG_CONDITION_HXX
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