#ifndef UTLFIXEDMEMORY_H
#define UTLFIXEDMEMORY_H

#ifdef _WIN32
#pragma once
#endif

#include "dbg.h"
#include "platform.h"

#include "memalloc.h"
#include "memdbgon.h"

#pragma warning (disable:4100)
#pragma warning (disable:4514)

#ifdef UTLFIXEDMEMORY_TRACK
#define UTLFIXEDMEMORY_TRACK_ALLOC()		MemAlloc_RegisterAllocation( "Sum of all UtlFixedMemory", 0, NumAllocated() * sizeof(T), NumAllocated() * sizeof(T), 0 )
#define UTLFIXEDMEMORY_TRACK_FREE()		if ( !m_pMemory ) ; else MemAlloc_RegisterDeallocation( "Sum of all UtlFixedMemory", 0, NumAllocated() * sizeof(T), NumAllocated() * sizeof(T), 0 )
#else
#define UTLFIXEDMEMORY_TRACK_ALLOC()		((void)0)
#define UTLFIXEDMEMORY_TRACK_FREE()		((void)0)
#endif


template< class T >
class CUtlFixedMemory
{
public:
	CUtlFixedMemory(int nGrowSize = 0, int nInitSize = 0);
	~CUtlFixedMemory();

	void Init(int nGrowSize = 0, int nInitSize = 0);

	T* Base() { return NULL; }
	const T* Base() const { return NULL; }

protected:
	struct BlockHeader_t;

public:
	class Iterator_t
	{
	public:
		Iterator_t(BlockHeader_t* p, int i) : m_pBlockHeader(p), m_nIndex(i) {}
		BlockHeader_t* m_pBlockHeader;
		intp m_nIndex;

		bool operator==(const Iterator_t it) const { return m_pBlockHeader == it.m_pBlockHeader && m_nIndex == it.m_nIndex; }
		bool operator!=(const Iterator_t it) const { return m_pBlockHeader != it.m_pBlockHeader || m_nIndex != it.m_nIndex; }
	};
	Iterator_t First() const { return m_pBlocks ? Iterator_t(m_pBlocks, 0) : InvalidIterator(); }
	Iterator_t Next(const Iterator_t& it) const
	{
		Assert(IsValidIterator(it));
		if (!IsValidIterator(it))
			return InvalidIterator();

		BlockHeader_t* RESTRICT pHeader = it.m_pBlockHeader;
		if (it.m_nIndex + 1 < pHeader->m_nBlockSize)
			return Iterator_t(pHeader, it.m_nIndex + 1);

		return pHeader->m_pNext ? Iterator_t(pHeader->m_pNext, 0) : InvalidIterator();
	}
	intp GetIndex(const Iterator_t& it) const
	{
		Assert(IsValidIterator(it));
		if (!IsValidIterator(it))
			return InvalidIndex();

		return (intp)(HeaderToBlock(it.m_pBlockHeader) + it.m_nIndex);
	}
	bool IsIdxAfter(intp i, const Iterator_t& it) const
	{
		Assert(IsValidIterator(it));
		if (!IsValidIterator(it))
			return false;

		if (IsInBlock(i, it.m_pBlockHeader))
			return i > GetIndex(it);

		for (BlockHeader_t* RESTRICT pbh = it.m_pBlockHeader->m_pNext; pbh; pbh = pbh->m_pNext)
		{
			if (IsInBlock(i, pbh))
				return true;
		}
		return false;
	}
	bool IsValidIterator(const Iterator_t& it) const { return it.m_pBlockHeader && it.m_nIndex >= 0 && it.m_nIndex < it.m_pBlockHeader->m_nBlockSize; }
	Iterator_t InvalidIterator() const { return Iterator_t(NULL, INVALID_INDEX); }

	T& operator[](intp i);
	const T& operator[](intp i) const;
	T& Element(intp i);
	const T& Element(intp i) const;

	bool IsIdxValid(intp i) const;

	static const intp INVALID_INDEX = 0;     
	static intp InvalidIndex() { return INVALID_INDEX; }

	int NumAllocated() const;
	int Count() const { return NumAllocated(); }

	void Grow(int num = 1);

	void EnsureCapacity(int num);

	void Purge();

protected:
	void Swap(CUtlFixedMemory< T >& mem);

	bool IsInBlock(intp i, BlockHeader_t* pBlockHeader) const
	{
		T* p = (T*)i;
		const T* p0 = HeaderToBlock(pBlockHeader);
		return p >= p0 && p < p0 + pBlockHeader->m_nBlockSize;
	}

	struct BlockHeader_t
	{
		BlockHeader_t* m_pNext;
		intp m_nBlockSize;
	};

	const T* HeaderToBlock(const BlockHeader_t* pHeader) const { return (T*)(pHeader + 1); }
	const BlockHeader_t* BlockToHeader(const T* pBlock) const { return (BlockHeader_t*)(pBlock)-1; }

	BlockHeader_t* m_pBlocks;
	int m_nAllocationCount;
	int m_nGrowSize;
};

template< class T >
CUtlFixedMemory<T>::CUtlFixedMemory(int nGrowSize, int nInitAllocationCount)
	: m_pBlocks(0), m_nAllocationCount(0), m_nGrowSize(0)
{
	Init(nGrowSize, nInitAllocationCount);
}

template< class T >
CUtlFixedMemory<T>::~CUtlFixedMemory()
{
	Purge();
}


template< class T >
void CUtlFixedMemory<T>::Swap(CUtlFixedMemory< T >& mem)
{
	V_swap(m_pBlocks, mem.m_pBlocks);
	V_swap(m_nAllocationCount, mem.m_nAllocationCount);
	V_swap(m_nGrowSize, mem.m_nGrowSize);
}


template< class T >
void CUtlFixedMemory<T>::Init(int nGrowSize    , int nInitSize    )
{
	Purge();

	m_nGrowSize = nGrowSize;

	Grow(nInitSize);
}

template< class T >
inline T& CUtlFixedMemory<T>::operator[](intp i)
{
	Assert(IsIdxValid(i));
	return *(T*)i;
}

template< class T >
inline const T& CUtlFixedMemory<T>::operator[](intp i) const
{
	Assert(IsIdxValid(i));
	return *(T*)i;
}

template< class T >
inline T& CUtlFixedMemory<T>::Element(intp i)
{
	Assert(IsIdxValid(i));
	return *(T*)i;
}

template< class T >
inline const T& CUtlFixedMemory<T>::Element(intp i) const
{
	Assert(IsIdxValid(i));
	return *(T*)i;
}


template< class T >
inline int CUtlFixedMemory<T>::NumAllocated() const
{
	return m_nAllocationCount;
}


template< class T >
inline bool CUtlFixedMemory<T>::IsIdxValid(intp i) const
{
#ifdef _DEBUG
	for (BlockHeader_t* pbh = m_pBlocks; pbh; pbh = pbh->m_pNext)
	{
		if (IsInBlock(i, pbh))
			return true;
	}
	return false;
#else
	return i != InvalidIndex();
#endif
}

template< class T >
void CUtlFixedMemory<T>::Grow(int num)
{
	if (num <= 0)
		return;

	int nBlockSize = m_nGrowSize;
	if (nBlockSize == 0)
	{
		if (m_nAllocationCount)
		{
			nBlockSize = m_nAllocationCount;
		}
		else
		{
			nBlockSize = (31 + sizeof(T)) / sizeof(T);
			Assert(nBlockSize);
		}
	}
	if (nBlockSize < num)
	{
		int n = (num + nBlockSize - 1) / nBlockSize;
		Assert(n * nBlockSize >= num);
		Assert((n - 1) * nBlockSize < num);
		nBlockSize *= n;
	}
	m_nAllocationCount += nBlockSize;

	MEM_ALLOC_CREDIT_CLASS();
	BlockHeader_t* RESTRICT pBlockHeader = (BlockHeader_t*)malloc(sizeof(BlockHeader_t) + nBlockSize * sizeof(T));
	if (!pBlockHeader)
	{
		Error("CUtlFixedMemory overflow!\n");
	}
	pBlockHeader->m_pNext = NULL;
	pBlockHeader->m_nBlockSize = nBlockSize;

	if (!m_pBlocks)
	{
		m_pBlocks = pBlockHeader;
	}
	else
	{
#if 1	          
		BlockHeader_t* RESTRICT  pbh = m_pBlocks;
		while (pbh->m_pNext)
		{
			pbh = pbh->m_pNext;
		}
		pbh->m_pNext = pBlockHeader;
#else
		pBlockHeader = m_pBlocks;
		pBlockHeader->m_pNext = m_pBlocks;
#endif
	}
}


template< class T >
inline void CUtlFixedMemory<T>::EnsureCapacity(int num)
{
	Grow(num - NumAllocated());
}


template< class T >
void CUtlFixedMemory<T>::Purge()
{
	if (!m_pBlocks)
		return;

	for (BlockHeader_t* pbh = m_pBlocks; pbh; )
	{
		BlockHeader_t* pFree = pbh;
		pbh = pbh->m_pNext;
		free(pFree);
	}
	m_pBlocks = NULL;
	m_nAllocationCount = 0;
}

#include "memdbgoff.h"

#endif