nodeiterator.h

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// © Copyright 2010 - 2016 BlackTopp Studios Inc.
/* This file is part of The Mezzanine Engine.

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/*
 *
 * Software, Files, Libraries and all other items referenced in this clause refers only
 * to the contents of this file and associated documentation.
 *
 * Pugixml parser - version 1.0
 * --------------------------------------------------------
 * Copyright © 2006-2012, by Arseny Kapoulkine (arseny.kapoulkine@gmail.com)
 * Report bugs and download new versions at http://pugixml.org/
 *
 * This library is distributed under the MIT License. See notice at the end
 * of this file.
 *
 * This work is based on the pugxml parser, which is:
 * Copyright © 2003, by Kristen Wegner (kristen@tima.net)
 */
#ifndef _xmlnodeiterator_h
#define _xmlnodeiterator_h

/// @file
/// @brief Contains the defintion of the @ref Mezzanine::XML::NodeIterator and @ref Mezzanine::XML::NamedNodeIterator class.

#include "datatypes.h"
#include "node.h"
#include "swig.h"



namespace Mezzanine
{
    namespace XML
    {

        /// @brief Child node iterator (a bidirectional iterator over a collection of @ref Node)
        /// @details Node::begin() and Node::attributes_begin() return iterators that point to the first node/attribute, respectively; Node::end() and Node::attributes_end() return past-the-end iterator for node/attribute list, respectively - this iterator can't be dereferenced, but decrementing it results in an iterator pointing to the last element in the list (except for empty lists, where decrementing past-the-end iterator results in undefined behavior). Past-the-end iterator is commonly used as a termination value for iteration loops. If you want to get an iterator that points to an existing handle, you can construct the iterator with the handle as a single constructor argument, like so: xml_node_iterator(node). For xml_attribute_iterator, you'll have to provide both an attribute and its parent node.\n\n
        /// Node::begin() and Node::end() return equal iterators if called on null Node; such iterators can't be dereferenced. Node::attributes_begin() and Node::attributes_end() behave the same way. For correct iterator usage this means that child node/attribute collections of null nodes appear to be empty.\n\n
        /// Both types of iterators have bidirectional iterator semantics (i.e. they can be incremented and decremented, but efficient random access is not supported) and support all usual iterator operations - comparison, dereference, etc. The iterators are invalidated if the node/attribute objects they're pointing to are removed from the tree; adding nodes/attributes does not invalidate any iterators.
        class MEZZ_LIB NodeIterator
        {
                friend class Node;

            private:

                /// @brief internal
                /// @brief The current @ref Node this iterator points to.
                mutable Node TargetNode;

                /// @internal
                /// @brief The node that contains this collection of nodes. Used in error situations.
                Node ParentNode;

                /// @brief Internal Constructor, almost a copy construtor
                /// @param ref Some of the internal data from another @ref NodeIterator specifically the Node it points to.
                /// @param ParentNode Some of the interal data from another @ref NodeIterator specifically the parent of the Node it points to.
                NodeIterator(NodeStruct* ref, NodeStruct* ParentNode);

            public:
                /// @brief An Iterator trait
                typedef ptrdiff_t difference_type;

                /// @brief An Iterator trait
                typedef Node value_type;

                /// @brief An Iterator trait
                typedef Node* pointer;

                /// @brief An Iterator trait
                typedef Node& reference;

                /// @brief An Iterator trait
                typedef std::bidirectional_iterator_tag iterator_category;

                /// @brief Default Constructor, makes a blank iterator
                NodeIterator();

                /// @brief Construct an iterator which points to the specified node
                /// @param node A Node that this iterator will point to.
                NodeIterator(const Node& node);

                /// @brief Compares this NodeIterator to another NodeIterator for equality
                /// @param rhs The Right Hand Side NodeIterator
                /// @return True if the internal data stored in Node this NodeIterator refers to is the same as the metadata in the other NodeIterator's Node, false otherwise.
                bool operator==(const NodeIterator& rhs) const;

                /// @brief Compares this NodeIterator to another NodeIterator for inequality
                /// @param rhs The Right Hand Side NodeIterator.
                /// @return False if the internal data stored in Node this NodeIterator refers to is the same as the metadata in the other NodeIterator's Node, True otherwise.
                bool operator!=(const NodeIterator& rhs) const;

                /// @brief Deferences this Iterator
                /// @return a Node reference to the node pointed at by this NodeIterator.
                Node& operator*() const;

                /// @brief Get the pointer the Node this points to.
                /// @return A pointer to the Node this NodeIterator references.
                Node* operator->() const;

                /// @brief Increment the iterator to the next member of the container.
                /// @return Returns a const NodeIterator.
                const NodeIterator& operator++();

                /// @brief Increment the iterator to the next member of the container.
                /// @return Returns a NodeIterator.
                NodeIterator operator++(int);

                /// @brief Decrement the iterator to the next member of the container.
                /// @return Returns a const NodeIterator.
                const NodeIterator& operator--();

                /// @brief Decrement the iterator to the next member of the container.
                /// @return Returns a NodeIterator.
                NodeIterator operator--(int);
        };

        // Named node range helper
        /// @brief Child node iterator (a forward iterator over a collection of @ref Node) only iterates over nodes with a given name.
        /// @details Node::begin() and Node::attributes_begin() return iterators that point to the first node/attribute, respectively; Node::end() and Node::attributes_end() return past-the-end iterator for node/attribute list, respectively - this iterator can't be dereferenced, but decrementing it results in an iterator pointing to the last element in the list (except for empty lists, where decrementing past-the-end iterator results in undefined behavior). Past-the-end iterator is commonly used as a termination value for iteration loops. If you want to get an iterator that points to an existing handle, you can construct the iterator with the handle as a single constructor argument, like so: xml_node_iterator(node). For xml_attribute_iterator, you'll have to provide both an attribute and its parent node.\n\n
        /// Node::begin() and Node::end() return equal iterators if called on null Node; such iterators can't be dereferenced. Node::attributes_begin() and Node::attributes_end() behave the same way. For correct iterator usage this means that child node/attribute collections of null nodes appear to be empty.\n\n
        /// Both types of iterators have bidirectional iterator semantics (i.e. they can be incremented and decremented, but efficient random access is not supported) and support all usual iterator operations - comparison, dereference, etc. The iterators are invalidated if the node/attribute objects they're pointing to are removed from the tree; adding nodes/attributes does not invalidate any iterators.
        class MEZZ_LIB NamedNodeIterator
        {
            public:
                /// @brief An Iterator trait
                typedef ptrdiff_t difference_type;

                /// @brief An Iterator trait
                typedef Node value_type;

                /// @brief An Iterator trait
                typedef Node* pointer;

                /// @brief An Iterator trait
                typedef Node& reference;

                /// @brief An Iterator trait
                typedef std::forward_iterator_tag iterator_category;

                /// @brief Default constructor
                NamedNodeIterator();

                /// @brief Construct an iterator which points to the specified node
                NamedNodeIterator(const Node& node, const Char8* Name );

                /// @brief Compares this NamedNodeIterator to another NamedNodeIterator for equality
                /// @param rhs The Right Hand Side NamedNodeIterator.
                /// @return False if the internal data stored in Node this NamedNodeIterator refers to is the same as the metadata in the other NamedNodeIterator's Node, True otherwise.
                bool operator==(const NamedNodeIterator& rhs) const;

                /// @brief Compares this NamedNodeIterator to another NamedNodeIterator for inequality
                /// @param rhs The Right Hand Side NamedNodeIterator.
                /// @return False if the internal data stored in Node this NamedNodeIterator refers to is the same as the metadata in the other NamedNodeIterator's Node, True otherwise.
                bool operator!=(const NamedNodeIterator& rhs) const;

                /// @brief Deferences this Iterator
                /// @return a Node reference to the node pointed at by this NamedNodeIterator.
                Node& operator*() const;

                /// @brief Get the pointer the Node this points to.
                /// @return A pointer to the Node this NamedNodeIterator references.
                Node* operator->() const;

                /// @brief Increment the iterator to the next member of the container.
                /// @return Returns a const NodeIterator.
                const NamedNodeIterator& operator++();

                /// @brief Increment the iterator to the next member of the container.
                /// @return Returns a NodeIterator.
                NamedNodeIterator operator++(int);

            private:
                /// @brief The Current @ref Node being pointed to by this iterator.
                mutable Node TargetNode;

                /// @brief The Name any nodet his points to will assume.
                const Char8* TargetName;
        };

    }
}// /namespace Mezzanine



#endif // Include guard

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