#ifndef _TCUINTERVAL_HPP
#define _TCUINTERVAL_HPP
/*-------------------------------------------------------------------------
 * drawElements Quality Program Tester Core
 * ----------------------------------------
 *
 * Copyright 2014 The Android Open Source Project
 *
 * 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 Interval arithmetic and floating point precisions.
 *//*--------------------------------------------------------------------*/

#include "tcuDefs.hpp"

#include "deMath.h"

#include <iostream>
#include <limits>
#include <cmath>

// Prevents an issue with instruction re-ordering around the calls to
// set rounding mode in TCU_SET_INTERVAL_BOUNDS.
// TODO(fxbug.dev/119516) replace with upstream solution.
#pragma STDC FENV_ACCESS ON

#define TCU_INFINITY	(::std::numeric_limits<float>::infinity())
#define TCU_NAN			(::std::numeric_limits<float>::quiet_NaN())

namespace tcu
{

// RAII context for temporarily changing the rounding mode
class ScopedRoundingMode
{
public:
							ScopedRoundingMode	(deRoundingMode mode)
								: m_oldMode (deGetRoundingMode()) { deSetRoundingMode(mode); }

							ScopedRoundingMode	(void) : m_oldMode (deGetRoundingMode()) {}

							~ScopedRoundingMode	(void)	{ deSetRoundingMode(m_oldMode); }

private:
							ScopedRoundingMode	(const ScopedRoundingMode&);
	ScopedRoundingMode&		operator=			(const ScopedRoundingMode&);

	const deRoundingMode	m_oldMode;
};

class Interval
{
public:
				// Empty interval.
				Interval			(void)
					: m_hasNaN		(false)
					, m_lo			(TCU_INFINITY)
					, m_hi			(-TCU_INFINITY)
					, m_warningLo	(-TCU_INFINITY)
					, m_warningHi	(TCU_INFINITY) {}

				// Intentionally not explicit. Conversion from double to Interval is common
				// and reasonable.
				Interval			(double val)
					: m_hasNaN		(!!deIsNaN(val))
					, m_lo			(m_hasNaN ? TCU_INFINITY : val)
					, m_hi			(m_hasNaN ? -TCU_INFINITY : val)
					, m_warningLo	(-TCU_INFINITY)
					, m_warningHi	(TCU_INFINITY) {}


				Interval(bool hasNaN_, double lo_, double hi_)
					: m_hasNaN(hasNaN_), m_lo(lo_), m_hi(hi_), m_warningLo(-TCU_INFINITY), m_warningHi(TCU_INFINITY) {}

				Interval(bool hasNaN_, double lo_, double hi_, double wlo_, double whi_)
					: m_hasNaN(hasNaN_), m_lo(lo_), m_hi(hi_), m_warningLo(wlo_), m_warningHi(whi_) {}

				Interval		(const Interval& a, const Interval& b)
					: m_hasNaN		(a.m_hasNaN || b.m_hasNaN)
					, m_lo			(de::min(a.lo(), b.lo()))
					, m_hi			(de::max(a.hi(), b.hi()))
					, m_warningLo	(de::min(a.warningLo(), b.warningLo()))
					, m_warningHi	(de::max(a.warningHi(), b.warningHi())) {}

	double		length			(void) const { return m_hi - m_lo; }
	double		lo				(void) const { return m_lo; }
	double		hi				(void) const { return m_hi; }
	double		warningLo		(void) const { return m_warningLo; }
	double		warningHi		(void) const { return m_warningHi; }
	bool		hasNaN			(void) const { return m_hasNaN; }
	Interval	nan				(void) const { return m_hasNaN ? TCU_NAN : Interval(); }
	bool		empty			(void) const { return m_lo > m_hi; }

	// The interval is represented in double, it can extend outside the range of smaller floating-point formats
	// and get rounded to infinity.
	bool		isFinite		(double maxValue) const { return m_lo > -maxValue && m_hi < maxValue; }
	bool		isOrdinary		(double maxValue) const { return !hasNaN() && !empty() && isFinite(maxValue); }

	void		warning			(double lo_, double hi_)
	{
		m_warningLo = lo_;
		m_warningHi = hi_;
	}

	Interval	operator|		(const Interval& other) const
	{
		return Interval(m_hasNaN || other.m_hasNaN,
						de::min(m_lo, other.m_lo),
						de::max(m_hi, other.m_hi),
						de::min(m_warningLo, other.m_warningLo),
						de::max(m_warningHi, other.m_warningHi));
	}

	Interval&	operator|=		(const Interval& other)
	{
		return (*this = *this | other);
	}

	Interval	operator&		(const Interval& other) const
	{
		return Interval(m_hasNaN && other.m_hasNaN,
						de::max(m_lo, other.m_lo),
						de::min(m_hi, other.m_hi),
						de::max(m_warningLo, other.m_warningLo),
						de::min(m_warningHi, other.m_warningHi));
	}

	Interval&	operator&=		(const Interval& other)
	{
		return (*this = *this & other);
	}

	bool		contains		(const Interval& other) const
	{
		return (other.lo() >= lo() && other.hi() <= hi() &&
				(!other.hasNaN() || hasNaN()));
	}

	bool		containsWarning(const Interval& other) const
	{
		return (other.lo() >= warningLo() && other.hi() <= warningHi() &&
			(!other.hasNaN() || hasNaN()));
	}

	bool		intersects		(const Interval& other) const
	{
		return ((other.hi() >= lo() && other.lo() <= hi()) ||
				(other.hasNaN() && hasNaN()));
	}

	Interval	operator-		(void) const
	{
		return Interval(hasNaN(), -hi(), -lo(), -warningHi(), -warningLo());
	}

	static Interval	unbounded	(bool nan = false)
	{
		return Interval(nan, -TCU_INFINITY, TCU_INFINITY);
	}

	double		midpoint		(void) const
	{
		const double	h = hi();
		const double	l = lo();

		if (h == -l)
			return 0.0;
		if (l == -TCU_INFINITY)
			return -TCU_INFINITY;
		if (h == TCU_INFINITY)
			return TCU_INFINITY;

		const bool		negativeH = ::std::signbit(h);
		const bool		negativeL = ::std::signbit(l);
		double			ret;

		if (negativeH != negativeL)
		{
			// Different signs. Adding both values should be safe.
			ret = (h + l) * 0.5;
		}
		else
		{
			// Same sign. Substracting low from high should be safe.
			ret = l + (h - l) * 0.5;
		}

		return ret;
	}

	bool		operator==		(const Interval& other) const
	{
		return ((m_hasNaN == other.m_hasNaN) &&
				((empty() && other.empty()) ||
				 (m_lo == other.m_lo && m_hi == other.m_hi)));
	}

private:
	bool		m_hasNaN;
	double		m_lo;
	double		m_hi;
	double		m_warningLo;
	double		m_warningHi;
} DE_WARN_UNUSED_TYPE;

inline Interval	operator+	(const Interval& x) { return x; }
Interval		exp2		(const Interval& x);
Interval		exp			(const Interval& x);
int				sign		(const Interval& x);
Interval		abs			(const Interval& x);
Interval		inverseSqrt	(const Interval& x);

Interval		operator+	(const Interval& x,		const Interval& y);
Interval		operator-	(const Interval& x,		const Interval& y);
Interval		operator*	(const Interval& x,		const Interval& y);
Interval		operator/	(const Interval& nom,	const Interval& den);

inline Interval& operator+=	(Interval& x,	const Interval& y) { return (x = x + y); }
inline Interval& operator-=	(Interval& x,	const Interval& y) { return (x = x - y); }
inline Interval& operator*=	(Interval& x,	const Interval& y) { return (x = x * y); }
inline Interval& operator/=	(Interval& x,	const Interval& y) { return (x = x / y); }

std::ostream&	operator<<	(std::ostream& os, const Interval& interval);

#define TCU_SET_INTERVAL_BOUNDS(DST, VAR, SETLOW, SETHIGH) do	\
{																\
	::tcu::ScopedRoundingMode	VAR##_ctx_;						\
	::tcu::Interval&			VAR##_dst_	= (DST);			\
	::tcu::Interval				VAR##_lo_;						\
	::tcu::Interval				VAR##_hi_;						\
																\
	{															\
		::tcu::Interval&	VAR = VAR##_lo_;					\
		::deSetRoundingMode(DE_ROUNDINGMODE_TO_NEGATIVE_INF);	\
		SETLOW;													\
	}															\
	{															\
		::tcu::Interval&	VAR = VAR##_hi_;					\
		::deSetRoundingMode(DE_ROUNDINGMODE_TO_POSITIVE_INF);	\
		SETHIGH;												\
	}															\
																\
	VAR##_dst_ = VAR##_lo_ | VAR##_hi_;							\
} while (::deGetFalse())

#define TCU_SET_INTERVAL(DST, VAR, BODY)						\
	TCU_SET_INTERVAL_BOUNDS(DST, VAR, BODY, BODY)

//! Set the interval DST to the image of BODY on ARG, assuming that BODY on
//! ARG is a monotone function. In practice, BODY is evaluated on both the
//! upper and lower bound of ARG, and DST is set to the union of these
//! results. While evaluating BODY, PARAM is bound to the bound of ARG, and
//! the output of BODY should be stored in VAR.
#define TCU_INTERVAL_APPLY_MONOTONE1(DST, PARAM, ARG, VAR, BODY) do		\
	{																	\
	const ::tcu::Interval&	VAR##_arg_		= (ARG);					\
	::tcu::Interval&		VAR##_dst_		= (DST);					\
	::tcu::Interval			VAR##_lo_;									\
	::tcu::Interval			VAR##_hi_;									\
	if (VAR##_arg_.empty())												\
		VAR##_dst_ = Interval();										\
	else																\
	{																	\
		{																\
			const double		PARAM	= VAR##_arg_.lo();				\
			::tcu::Interval&	VAR		= VAR##_lo_;					\
			BODY;														\
		}																\
		{																\
			const double		PARAM	= VAR##_arg_.hi();				\
			::tcu::Interval&	VAR		= VAR##_hi_;					\
			BODY;														\
		}																\
		VAR##_dst_ = VAR##_lo_ | VAR##_hi_;								\
	}																	\
	if (VAR##_arg_.hasNaN())											\
		VAR##_dst_ |= TCU_NAN;											\
} while (::deGetFalse())

#define TCU_INTERVAL_APPLY_MONOTONE2(DST, P0, A0, P1, A1, VAR, BODY)	\
	TCU_INTERVAL_APPLY_MONOTONE1(										\
		DST, P0, A0, tmp2_,												\
		TCU_INTERVAL_APPLY_MONOTONE1(tmp2_, P1, A1, VAR, BODY))

#define TCU_INTERVAL_APPLY_MONOTONE3(DST, P0, A0, P1, A1, P2, A2, VAR, BODY) \
	TCU_INTERVAL_APPLY_MONOTONE1(										\
		DST, P0, A0, tmp3_,												\
		TCU_INTERVAL_APPLY_MONOTONE2(tmp3_, P1, A1, P2, A2, VAR, BODY))

typedef double		DoubleFunc1			(double);
typedef double		DoubleFunc2			(double, double);
typedef double		DoubleFunc3			(double, double, double);
typedef Interval	DoubleIntervalFunc1	(double);
typedef Interval	DoubleIntervalFunc2	(double, double);
typedef Interval	DoubleIntervalFunc3	(double, double, double);

Interval	applyMonotone	(DoubleFunc1&			func,
							 const Interval&		arg0);
Interval	applyMonotone	(DoubleFunc2&			func,
							 const Interval&		arg0,
							 const Interval&		arg1);
Interval	applyMonotone	(DoubleIntervalFunc1&	func,
							 const Interval&		arg0);
Interval	applyMonotone	(DoubleIntervalFunc2&	func,
							 const Interval&		arg0,
							 const Interval&		arg1);


} // tcu

#endif // _TCUINTERVAL_HPP