#pragma once

#include "tl/detail/prologue.h"
#include "EASTL/functional.h"

namespace tl
{

using namespace eastl;

template <class T>
constexpr inline void hash_and_combine(uint32_t& seed, const T& v) noexcept
{
	//the result of the hasher is size_t so - if used in arithmetic - it might produce different results in 32 and 64 bit platforms
	//therefore we cast it here to 32 bit.
	tl::hash<T> hasher;
	seed ^= static_cast<uint32_t>(hasher(v)) + static_cast<uint32_t>(0x9e3779b9) + (seed << 6) + (seed >> 2);
}

template <class T>
constexpr inline void hash_and_combine(uint64_t& seed, const T& v) noexcept
{
	//the result of the hasher is size_t so - if used in arithmetic - it might produce different results in 32 and 64 bit platforms
	//therefore we cast it here to 32 bit.
	tl::hash<T> hasher;
	seed ^= static_cast<uint32_t>(hasher(v)) + 0xA6E9377DAF75BDFEULL + (seed << 6) + (seed >> 2);
}

#if defined(TL_PLATFORM_OSX_FAMILY)
template <class T>
constexpr inline void hash_and_combine(size_t& seed, const T& v) noexcept
{
	tl::hash<T> hasher;
	seed ^= hasher(v) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
}
#endif


constexpr inline void hash_combine(uint32_t& seed, const uint32_t v) noexcept
{
	//the result of the hasher is size_t so - if used in arithmetic - it might produce different results in 32 and 64 bit platforms
	//therefore we cast it here to 32 bit.
	seed ^= v + static_cast<uint32_t>(0x9e3779b9u) + (seed << 6) + (seed >> 2);
}

constexpr inline void hash_combine(uint64_t& seed, const uint64_t v) noexcept
{
	//the result of the hasher is size_t so - if used in arithmetic - it might produce different results in 32 and 64 bit platforms
	//therefore we cast it here to 32 bit.	
	seed ^= static_cast<uint32_t>(v) + 0xA6E9377DAF75BDFEULL + (seed << 6) + (seed >> 2);
}

#if defined(TL_PLATFORM_OSX_FAMILY)
constexpr inline void hash_combine(size_t& seed, const size_t v) noexcept
{
	seed ^= v + 0x9e3779b9 + (seed << 6) + (seed >> 2);
}
#endif

}