anki-3d-engine/include/anki/util/DArray.h

// Copyright (C) 2009-2015, Panagiotis Christopoulos Charitos.
// All rights reserved.
// Code licensed under the BSD License.
// http://www.anki3d.org/LICENSE

#ifndef ANKI_UTIL_D_ARRAY_H
#define ANKI_UTIL_D_ARRAY_H

#include "anki/util/Allocator.h"
#include "anki/util/NonCopyable.h"
#include "anki/util/Functions.h"

namespace anki {

/// @addtogroup util_containers
/// @{

/// Dynamic array with manual destruction. It doesn't hold the allocator and 
/// that makes it compact. At the same time that requires manual destruction. 
/// Used in permanent classes.
template<typename T>
class DArray: public NonCopyable
{
public:
	using Value = T;
	using Iterator = Value*;
	using ConstIterator = const Value*;
	using Reference = Value&;
	using ConstReference = const Value&;

	DArray()
	:	m_data(nullptr),
		m_size(0)
	{}

	/// Move.
	DArray(DArray&& b)
	:	DArray()
	{
		move(b);
	}

	~DArray()
	{
		ANKI_ASSERT(m_data == nullptr && m_size == 0 
			&& "Requires manual destruction");
	}

	/// Move.
	DArray& operator=(DArray&& b)
	{
		move(b);
		return *this;
	}

	Reference operator[](const PtrSize n)
	{
		ANKI_ASSERT(n < m_size);
		return m_data[n];
	}

	ConstReference operator[](const PtrSize n) const
	{
		ANKI_ASSERT(n < m_size);
		return m_data[n];
	}

	/// Make it compatible with the C++11 range based for loop.
	Iterator getBegin()
	{
		return &m_data[0];
	}

	/// Make it compatible with the C++11 range based for loop.
	ConstIterator getBegin() const
	{
		return &m_data[0];
	}

	/// Make it compatible with the C++11 range based for loop.
	Iterator getEnd()
	{
		return &m_data[0] + m_size;
	}

	/// Make it compatible with the C++11 range based for loop.
	ConstIterator getEnd() const
	{
		return &m_data[0] + m_size;
	}

	/// Make it compatible with the C++11 range based for loop.
	Iterator begin()
	{
		return getBegin();
	}

	/// Make it compatible with the C++11 range based for loop.
	ConstIterator begin() const
	{
		return getBegin();
	}

	/// Make it compatible with the C++11 range based for loop.
	Iterator end()
	{
		return getEnd();
	}

	/// Make it compatible with the C++11 range based for loop.
	ConstIterator end() const
	{
		return getEnd();
	}

	/// Get first element.
	Reference getFront() 
	{
		return m_data[0];
	}

	/// Get first element.
	ConstReference getFront() const
	{
		return m_data[0];
	}

	/// Get last element.
	Reference getBack() 
	{
		return m_data[m_size - 1];
	}

	/// Get last element.
	ConstReference getBack() const
	{
		return m_data[m_size - 1];
	}

	/// Get last element.
	ConstReference back() const
	{
		return m_data[m_size - 1];
	}

	PtrSize getSize() const
	{
		return m_size;
	}

	PtrSize getByteSize() const
	{
		return m_size * sizeof(Value);
	}

	Bool isEmpty() const
	{
		return m_size == 0;
	}

	PtrSize getSizeInBytes() const
	{
		return m_size * sizeof(Value);
	}

	/// Create the array.
	template<typename TAllocator>
	ANKI_USE_RESULT Error create(TAllocator alloc, PtrSize size)
	{
		ANKI_ASSERT(m_data == nullptr && m_size == 0);
		Error err = ErrorCode::NONE;

		destroy(alloc);

		if(size > 0)
		{
			m_data = alloc.template newArray<Value>(size);
			if(m_data)
			{
				m_size = size;
			}
			else
			{
				err = ErrorCode::OUT_OF_MEMORY;
			}
		}

		return err;
	}

	/// Create the array.
	template<typename TAllocator>
	ANKI_USE_RESULT Error create(TAllocator alloc, PtrSize size, const Value& v)
	{
		ANKI_ASSERT(m_data == nullptr && m_size == 0);
		Error err = ErrorCode::NONE;

		if(size > 0)
		{
			m_data = alloc.template newArray<Value>(size, v);
			if(m_data)
			{
				m_size = size;
			}
			else
			{
				err = ErrorCode::OUT_OF_MEMORY;
			}
		}

		return err;
	}

	/// Grow the array.
	template<typename TAllocator>
	ANKI_USE_RESULT Error resize(TAllocator alloc, PtrSize size)
	{
		ANKI_ASSERT(size > 0);
		DArray newArr;
		Error err = newArr.create(alloc, size);

		if(!err)
		{
			PtrSize minSize = min<PtrSize>(size, m_size);
			for(U i = 0; i < minSize; i++)
			{
				newArr[i] = std::move((*this)[i]);
			}

			destroy(alloc);
			move(newArr);
		}

		return err;
	}

	/// Destroy the array.
	template<typename TAllocator>
	void destroy(TAllocator alloc)
	{
		if(m_data)
		{
			ANKI_ASSERT(m_size > 0);
			alloc.deleteArray(m_data, m_size);

			m_data = nullptr;
			m_size = 0;
		}

		ANKI_ASSERT(m_data == nullptr && m_size == 0);
	}

protected:
	Value* m_data;
	U32 m_size;

	void move(DArray& b)
	{
		ANKI_ASSERT(m_data == nullptr && m_size == 0
			&& "Cannot move before destroying");
		m_data = b.m_data;
		b.m_data = nullptr;
		m_size = b.m_size;
		b.m_size = 0;
	}
};

/// Dynamic array with automatic destruction. It's the same as DArray but it 
/// holds the allocator in order to perform automatic destruction. Use it for
/// temp operations and on transient classes.
template<typename T, typename TAlloc = HeapAllocator<T>>
class DArrayAuto: public DArray<T>
{
public:
	using Base = DArray<T>;
	using Value = T;
	using Allocator = TAlloc;

	DArrayAuto(Allocator alloc)
	:	Base(),
		m_alloc(alloc)
	{}

	/// Move.
	DArrayAuto(DArrayAuto&& b)
	:	DArrayAuto()
	{
		move(b);
	}

	~DArrayAuto()
	{
		Base::destroy(m_alloc);
	}

	/// Move.
	DArrayAuto& operator=(DArrayAuto&& b)
	{
		move(b);
		return *this;
	}

	/// Create the array.
	ANKI_USE_RESULT Error create(PtrSize size)
	{
		return Base::create(m_alloc, size);
	}

	/// Create the array.
	ANKI_USE_RESULT Error create(PtrSize size, const Value& v)
	{
		return Base::create(m_alloc, size, v);
	}

	/// Grow the array.
	ANKI_USE_RESULT Error resize(PtrSize size)
	{
		return Base::resize(m_alloc, size);
	}

private:
	Allocator m_alloc;

	void move(DArrayAuto& b)
	{
		Base::move(b);
		m_alloc = b.m_alloc;
	}
};

/// Array with preallocated memory.
template<typename T>
class SArray: public DArray<T>
{
public:
	using Base = DArray<T>;
	using Value = T;

	SArray()
	:	Base()
	{}

	SArray(void* mem, PtrSize size)
	:	Base()
	{
		ANKI_ASSERT(mem);
		ANKI_ASSERT(size);
		Base::m_data = static_cast<Value*>(mem);
		Base::m_size = size;
	}

	/// Move.
	SArray(SArray&& b)
	:	SArray()
	{
		move(b);
	}

	~SArray()
	{
#if ANKI_ASSERTIONS
		Base::m_data = nullptr;
		Base::m_size = 0;
#endif
	}

	/// Move.
	SArray& operator=(SArray&& b)
	{
		move(b);
		return *this;
	}

private:
	void move(SArray& b)
	{
		Base::m_data = b.m_data;
		b.m_data = nullptr;
		Base::m_size = b.m_size;
		b.m_size = 0;
	}
};
/// @}

} // end namespace anki

#endif