// Copyright 2019 The SwiftShader Authors. All Rights Reserved.
//
// 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.

#ifndef sw_ID_hpp
#define sw_ID_hpp

#include <cstdint>
#include <unordered_map>

namespace sw {

// SpirvID is a strongly-typed identifier backed by a uint32_t.
// The template parameter T is not actually used by the implementation of
// ID; instead it is used to prevent implicit casts between identifiers of
// different T types.
// IDs are typically used as a map key to value of type T.
template<typename T>
class SpirvID
{
public:
	SpirvID()
	    : id(0)
	{}
	SpirvID(uint32_t id)
	    : id(id)
	{}
	bool operator==(const SpirvID<T> &rhs) const { return id == rhs.id; }
	bool operator!=(const SpirvID<T> &rhs) const { return id != rhs.id; }
	bool operator<(const SpirvID<T> &rhs) const { return id < rhs.id; }

	// value returns the numerical value of the identifier.
	uint32_t value() const { return id; }

private:
	uint32_t id;
};

// HandleMap<T> is an unordered map of SpirvID<T> to T.
template<typename T>
using HandleMap = std::unordered_map<SpirvID<T>, T>;
}  // namespace sw

namespace std {
// std::hash implementation for sw::SpirvID<T>
template<typename T>
struct hash<sw::SpirvID<T> >
{
	std::size_t operator()(const sw::SpirvID<T> &id) const noexcept
	{
		return std::hash<uint32_t>()(id.value());
	}
};

}  // namespace std

#endif  // sw_ID_hpp