95 lines
2.8 KiB
C++
95 lines
2.8 KiB
C++
/******************************************************************************/
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/* VARIOUS ALGORITHMS *********************************************************/
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/******************************************************************************/
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#ifndef _H_EBCL_ALGORITHMS
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#define _H_EBCL_ALGORITHMS
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#include <ebcl/Types.hh>
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#include <ebcl/Arrays.hh>
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namespace ebcl {
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/*= VISITOR ==================================================================*/
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/* Helper for the visitor algorithm. Provides the various types used internally
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* as well as means to create and dereference values for the stack.
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*
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* The template's default implementation are not functional. It is specialised
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* later for references and non-references.
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*/
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template<
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typename T_Ref ,
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bool IsRef = std::is_reference< T_Ref >::value
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> struct T_VisitorHelper_
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{
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using T_Opt = void; // Optional value type
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using T_StackRef = void; // Stack reference type
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static T_StackRef mkext( T_Ref ) noexcept; // Create stack reference
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static T_Ref deref( T_StackRef ) noexcept; // Dereference stack entry
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};
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template<
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// Node type
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typename T_Node ,
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// Node reference type; by default, use values for arithmetic types and
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// pointers, and references for other types
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typename R_Node = std::conditional_t<
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std::is_arithmetic< T_Node >::value || std::is_pointer< T_Node >::value ,
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T_Node , T_Node& >
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> class T_Visitor
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{
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private:
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using Helper_ = T_VisitorHelper_< R_Node >;
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public:
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// Optional value
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using T_OptNode = typename Helper_::T_Opt;
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// Node browser. Returns the Nth child of the specified node, or null
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// if there are no children left.
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using F_NodeBrowser = std::function< T_OptNode( R_Node , uint32_t ) >;
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// Node action. Second parameter indicates whether the action is
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// being called before (false) or after (true) visiting the children.
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using F_NodeAction = std::function< bool( R_Node , bool ) >;
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private:
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using T_StackRef_ = typename Helper_::T_StackRef;
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// State of a stack entry
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enum E_State_ {
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BEFORE , // Must enter the node
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CHILDREN , // Going through children
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AFTER // Must exit the node
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};
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struct T_NodeRef_ {
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T_StackRef_ node;
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uint32_t child;
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E_State_ state{ BEFORE };
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explicit T_NodeRef_( R_Node node ) noexcept
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: node( Helper_::mkext( node ) ) , child( 0 ) {}
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explicit T_NodeRef_( R_Node node , uint32_t child ) noexcept
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: node( Helper_::mkext( node ) ) , child( child ) {}
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};
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F_NodeBrowser nodeBrowser_;
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T_AutoArray< T_NodeRef_ , 8 > stack_;
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public:
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T_Visitor( ) = delete;
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T_Visitor( T_Visitor const& ) = default;
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T_Visitor( T_Visitor&& ) noexcept = default;
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explicit T_Visitor( F_NodeBrowser browser ) noexcept;
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void visit( R_Node root , F_NodeAction action );
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};
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} // namespace
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#endif // _H_EBCL_ALGORITHMS
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#include <ebcl/inline/Algorithms.hh>
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