#include "ptrlist.h"


CPtrList::CPtrList()
{
	Initialize();
}

CPtrList::CPtrList(const CPtrList& list)
{
	Initialize();
	CreateLocalCopy(list.m_pHead);
}

const CPtrList& CPtrList::operator=(const CPtrList& right)
{
	if (&right != this)
	{
		RemoveAll();
		Initialize();
		CreateLocalCopy(right.m_pHead);
	}
	return *this;
}

void CPtrList::Initialize()
{
	m_pHead = NULL;
	m_pTail = NULL;
	m_dwCount = 0;
}

CPtrList::~CPtrList()
{
	RemoveAll();
}

void CPtrList::CreateLocalCopy(const _DATALISTELEMENT* pHead)
{
	void* pData = NULL;
	_DATALISTELEMENT* pNode = NULL;

	RemoveAll();

	if (!pHead)
	{
		return;
	}

	if (pHead->pData)
	{
		AddTail(pHead->pData);
	}

	pNode = pHead->pNext;
	while (pNode)
	{
		pData = pNode->pData;
		if (pData)
		{
			AddTail(pData);
		}
		pNode = pNode->pNext;
	}
}

DWORD CPtrList::GetCount() const
{
	return m_dwCount;
}

POSITION CPtrList::GetHeadPosition() const
{
	return (POSITION) m_pHead;
}

void* CPtrList::GetNext(POSITION& rPosition) const
{
	_DATALISTELEMENT* pNode = (_DATALISTELEMENT*) rPosition;
	if (!pNode)
	{
		return NULL;
	}
	rPosition = (POSITION) pNode->pNext;
	return pNode->pData;
}

void* CPtrList::GetAt(POSITION position) const
{
	_DATALISTELEMENT* pNode = (_DATALISTELEMENT*) position;
	if (!pNode)
	{
		return NULL;
	}
	return pNode->pData;
}

POSITION CPtrList::Find(void* p, POSITION startAfter /* = NULL */) const
{
	_DATALISTELEMENT* pNode = (_DATALISTELEMENT*) startAfter;
	if (pNode == NULL)
	{
		pNode = m_pHead;
	}
	else
	{
		pNode = pNode->pNext;  // start after the one specified
	}
	while (pNode != NULL)
	{
		if (p == pNode->pData)
		{
			return (POSITION) pNode;
		}
		pNode = pNode->pNext;
	}
	return NULL;
}

POSITION CPtrList::FindIndex(DWORD dwIndex) const
{
	if (dwIndex >= m_dwCount)
	{
		return NULL;
	}
	_DATALISTELEMENT* pNode = m_pHead;
	while (dwIndex--)
	{
		pNode = pNode->pNext;
	}
	return (POSITION) pNode;
}

void CPtrList::RemoveAt(POSITION position)
{
	_DATALISTELEMENT* pOldNode = (_DATALISTELEMENT*) position;
	if (!pOldNode)
	{
		return;
	}
	if (pOldNode == m_pHead)
	{
		m_pHead = pOldNode->pNext;
	}
	else
	{
		pOldNode->pPrev->pNext = pOldNode->pNext;
	}
	if (pOldNode == m_pTail)
	{
		m_pTail = pOldNode->pPrev;
	}
	else
	{
		pOldNode->pNext->pPrev = pOldNode->pPrev;
	}
	FreeNode(pOldNode);
}

void CPtrList::RemoveAll()
{
	_DATALISTELEMENT* pNode = NULL;
	_DATALISTELEMENT* pNext = NULL;
	pNode = m_pHead;
	while (pNode)
	{
		pNext = pNode->pNext;
		FreeNode(pNode);
		pNode = pNext;
	}
	m_pHead = NULL;
	m_pTail = NULL;
	m_dwCount = 0;

}

void CPtrList::FreeNode(_DATALISTELEMENT* pNode)
{
	if ((pNode == NULL) || (m_dwCount == 0))
	{
		return;
	}
	delete pNode;
	m_dwCount--;
}

void CPtrList::AddTail(void* p)
{
	_DATALISTELEMENT* pNode = NULL;
	_DATALISTELEMENT* pPrevious = NULL;
	pNode = new _DATALISTELEMENT;
	if (pNode)
	{
		pNode->pData = p;
		pNode->pNext = NULL;
		if (m_pTail)
		{
			pNode->pPrev = m_pTail;
			m_pTail->pNext = pNode;
		}
		else
		{
			pNode->pPrev = NULL;
			m_pHead = pNode;
		}
		m_dwCount++;
		m_pTail = pNode;
	}
}