uox3/source/GenericList.h

#if !defined( __GENERICLIST_H__ )
#define __GENERICLIST_H__
//o------------------------------------------------------------------------------------------------o
//|	File	-	GenericList.h
//|	Date	-	2021-05-04
//o------------------------------------------------------------------------------------------------o
//|	Purpose	-	Created as a counterpart of CDataList, based on std::list this class will behave
//|						as expected when removing records in the middle of the array.
//|
//|			-	Version Historyz
//|
//|					1.0		 		2021-05-04
//|					Initial implementation.
//o------------------------------------------------------------------------------------------------o
#include <iostream>
#include <cstdint>
#include <unordered_set>
#include <algorithm>
//o------------------------------------------------------------------------------------------------o
// GenericList
//o------------------------------------------------------------------------------------------------o
// Why this design can lead to issues
// It stores iterators in an array (for push/pop).  However
// if any object is deleted, there is no guarantee that the existing iterators
// remain valid.  One may assume , because of a list, that each iterator is independent.
// However, the implementation is not defined, and the spec does not guarantee itererator
// validity outside the scope of use.  On the note of implementation, Soustrap has stated
// that one shoud almost always use vector versus list, as in most cases (due to implementation)
// it is faster.  This can be reimplemented if one assumes: 1. it only is a list of pointers, which it seems to be,
// and 2: one does not have duplicates stored.  If those are valid, this class can be reimpemented without storing
// iterators outside the working scope
//o------------------------------------------------------------------------------------------------o
template <typename T>
class GenericList
{

private:
	using GENERICLIST = std::list<T>;
	using GENERICLIST_ITERATOR = typename std::list<T>::iterator;
	using GENERICLIST_CITERATOR = typename std::list<T>::const_iterator;

	std::list<T> objData;
	typename std::list<T>::iterator	objIterator;
	std::vector<GENERICLIST_ITERATOR> objIteratorBackup;

	auto FindEntry( T toFind ) -> GENERICLIST_ITERATOR
	{
		return std::find( objData.begin(), objData.end(), toFind );
	}

	auto Begin() -> bool
	{
		return ( objIterator == objData.begin() );
	}
public:

	GenericList()
	{
		objData.resize( 0 );
		objIteratorBackup.resize( 0 );
		objIterator = objData.end();
	}

	~GenericList() = default;

	auto collection() const -> const std::list<T> &
	{
		return objData;
	}

	auto collection() -> std::list<T>&
	{
		return objData;
	}

	auto GetCurrent() -> T
	{
		T rValue = nullptr;
		if( objIterator != objData.end() )
		{
			rValue = ( *objIterator );
		}
		return rValue;
	}

	auto First() -> T
	{
		objIterator = objData.end();
		return Next();
	}

	auto Next() -> T
	{
		T rValue = nullptr;
		if( !Begin() )
		{
			--objIterator;
			rValue = ( *objIterator );
		}
		else
		{
			objIterator = objData.end();
		}
		return rValue;
	}

	auto Finished() -> bool
	{
		return ( objIterator == objData.end() );
	}

	auto Num() const -> size_t
	{
		return objData.size();
	}

	auto Clear() -> void
	{
		objData.clear();
	}

	auto Add( T toAdd, bool checkForExisting = true ) -> bool
	{
		if( checkForExisting && FindEntry( toAdd ) != objData.end() )
		{
			return false;
		}

		const bool updateCounter = ( objIterator == objData.end() );
		objData.push_back( toAdd );
		if( updateCounter )
		{
			objIterator = objData.end();
		}

		return true;
	}

	auto AddInFront( T toAdd, bool checkForExisting = true ) -> bool
	{
		if( checkForExisting && FindEntry( toAdd ) != objData.end() )
		{
			return false;
		}

		const bool updateCounter = ( objIterator == objData.end() );
		objData.push_front( toAdd );
		if( updateCounter )
		{
			objIterator = objData.end();
		}

		return true;
	}

	auto Remove( T toRemove, bool handleAlloc = false ) -> bool
	{
		GENERICLIST_ITERATOR rIter = FindEntry( toRemove );
		if( rIter != objData.end() )
		{
			if( objIterator != objData.end() && rIter == objIterator )
			{
				++objIterator;
			}

			for( size_t q = 0; q < objIteratorBackup.size(); ++q )
			{
				if( objIteratorBackup[q] != objData.end() && rIter == objIteratorBackup[q] )
				{
					++objIteratorBackup[q];
				}
			}
			objData.erase( rIter );

			if( handleAlloc )
			{
				delete toRemove;
			}
			return true;
		}
		return false;
	}

	auto Pop() -> void
	{
		if( !objIteratorBackup.empty() )
		{
			objIterator = objIteratorBackup.back();
			objIteratorBackup.pop_back();
		}
		else
		{
			objIterator = objData.end();
		}
	}

	auto Push() -> void
	{
		objIteratorBackup.push_back(objIterator);
	}

	auto Reverse() -> void
	{
		objData.reverse();
	}

	auto Sort() -> void
	{
		objData.sort();
	}

	auto Sort( bool Comparer( T one, T two )) -> void
	{
		objData.sort( Comparer );
	}
};

//o------------------------------------------------------------------------------------------------o
// RegionSerialList
//o------------------------------------------------------------------------------------------------o
class RegionSerialList
{
private:
	std::unordered_set<SERIAL> objSerials;

public:
	RegionSerialList() = default;
	~RegionSerialList() = default;

	auto Add( SERIAL toAdd ) -> bool
	{
		auto insertResult = objSerials.insert( toAdd );
		return insertResult.second;
	}

	auto Remove( SERIAL toRemove ) -> size_t
	{
		return objSerials.erase( toRemove );
	}
};

#endif // __GENERICLIST_H__