#ifndef _VKTPIPELINEUNIQUERANDOMITERATOR_HPP
#define _VKTPIPELINEUNIQUERANDOMITERATOR_HPP
/*------------------------------------------------------------------------
 * Vulkan Conformance Tests
 * ------------------------
 *
 * Copyright (c) 2015 The Khronos Group Inc.
 * Copyright (c) 2015 Imagination Technologies Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 *//*!
 * \file
 * \brief Iterator over a unique sequence of items
 *//*--------------------------------------------------------------------*/

#include "tcuDefs.hpp"
#include "deRandom.hpp"
#include <set>
#include <vector>

namespace vkt
{
namespace pipeline
{

template <typename T>
class UniqueRandomIterator
{
public:
							UniqueRandomIterator	(deUint32 numItems, deUint32 numValues, int seed);
	virtual					~UniqueRandomIterator	(void) {}
	bool					hasNext					(void) const;
	T						next					(void);
	void					reset					(void);

protected:
	virtual T				getIndexedValue			(deUint32 index) = 0;

private:
	std::vector<deUint32>	m_indices;
	size_t					m_currentIndex;
};

template <typename T>
UniqueRandomIterator<T>::UniqueRandomIterator (deUint32 numItems, deUint32 numValues, int seed)
{
	de::Random rnd(seed);

	DE_ASSERT(numItems <= numValues);

	if (numItems == numValues)
	{
		// Fast way to populate the index sequence
		m_indices = std::vector<deUint32>(numItems);

		for (deUint32 itemNdx = 0; itemNdx < numItems; itemNdx++)
			m_indices[itemNdx] = itemNdx;
	}
	else
	{
		std::set<deUint32> uniqueIndices;

		// Populate set with "numItems" unique values between 0 and numValues - 1
		while (uniqueIndices.size() < numItems)
			uniqueIndices.insert(rnd.getUint32() % numValues);

		// Copy set into index sequence
		m_indices = std::vector<deUint32>(uniqueIndices.begin(), uniqueIndices.end());
	}

	// Scramble the indices
	rnd.shuffle(m_indices.begin(), m_indices.end());

	reset();
}

template <typename T>
bool UniqueRandomIterator<T>::hasNext (void) const
{
	return m_currentIndex < m_indices.size();
}

template <typename T>
T UniqueRandomIterator<T>::next (void)
{
	DE_ASSERT(m_currentIndex < m_indices.size());

	return getIndexedValue(m_indices[m_currentIndex++]);
}

template <typename T>
void UniqueRandomIterator<T>::reset (void)
{
	m_currentIndex = 0;
}

} // pipeline
} // vkt

#endif // _VKTPIPELINEUNIQUERANDOMITERATOR_HPP