#pragma once

////////////////////////////////////////////////////////////////////////////////
// The MIT License (MIT)
//
// Copyright (c) 2019 Nicholas Frechette & Animation Compression Library contributors
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
////////////////////////////////////////////////////////////////////////////////

#include "acl/core/impl/compiler_utils.h"

#include <rtm/math.h>

ACL_IMPL_FILE_PRAGMA_PUSH

namespace acl
{
	//////////////////////////////////////////////////////////////////////////
	// Stores the floating point environment information.
	//////////////////////////////////////////////////////////////////////////
	struct fp_environment
	{
#if defined(RTM_SSE2_INTRINSICS)
		unsigned int exception_mask;
#elif defined(RTM_NEON_INTRINSICS)
		// TODO: Implement on ARM. API to do this is not consistent across Android, Windows ARM, and iOS
		// and on top of it, most ARM CPUs out there do not raise the SIGFPE trap so they are silent
#endif
	};

	//////////////////////////////////////////////////////////////////////////
	// Enables floating point exceptions for invalid operations, division by zero, and overflow.
	//////////////////////////////////////////////////////////////////////////
	inline void enable_fp_exceptions(fp_environment& out_old_env)
	{
#if defined(RTM_SSE2_INTRINSICS)
		// We only care about SSE and not x87
		// Clear any exceptions that might have been raised already
		_MM_SET_EXCEPTION_STATE(0);
		// Cache the exception mask we had so we can restore it later
		out_old_env.exception_mask = _MM_GET_EXCEPTION_MASK();
		// Enable our exceptions
		const unsigned int exception_flags = _MM_MASK_INVALID | _MM_MASK_DIV_ZERO | _MM_MASK_OVERFLOW;
		_MM_SET_EXCEPTION_MASK(~exception_flags & _MM_MASK_MASK);
#else
		(void)out_old_env;
#endif
	}

	//////////////////////////////////////////////////////////////////////////
	// Disables all floating point exceptions.
	//////////////////////////////////////////////////////////////////////////
	inline void disable_fp_exceptions(fp_environment& out_old_env)
	{
#if defined(RTM_SSE2_INTRINSICS)
		// We only care about SSE and not x87
		// Cache the exception mask we had so we can restore it later
		out_old_env.exception_mask = _MM_GET_EXCEPTION_MASK();
		// Disable all exceptions
		_MM_SET_EXCEPTION_MASK(_MM_MASK_MASK);
#else
		(void)out_old_env;
#endif
	}

	//////////////////////////////////////////////////////////////////////////
	// Restores a previously set floating point environment.
	//////////////////////////////////////////////////////////////////////////
	inline void restore_fp_exceptions(const fp_environment& env)
	{
#if defined(RTM_SSE2_INTRINSICS)
		// We only care about SSE and not x87
		// Clear any exceptions that might have been raised already
		_MM_SET_EXCEPTION_STATE(0);
		// Restore our old mask value
		_MM_SET_EXCEPTION_MASK(env.exception_mask);
#else
		(void)env;
#endif
	}

	//////////////////////////////////////////////////////////////////////////
	// Enables floating point exceptions in the parent scope for invalid operations, division by zero, and overflow.
	//////////////////////////////////////////////////////////////////////////
	class scope_enable_fp_exceptions
	{
	public:
		scope_enable_fp_exceptions()
		{
			enable_fp_exceptions(env);
		}

		~scope_enable_fp_exceptions()
		{
			restore_fp_exceptions(env);
		}

	private:
		// Prevent copy or move
		scope_enable_fp_exceptions(const scope_enable_fp_exceptions&) = delete;
		scope_enable_fp_exceptions(scope_enable_fp_exceptions&&) = delete;
		scope_enable_fp_exceptions& operator=(const scope_enable_fp_exceptions&) = delete;
		scope_enable_fp_exceptions& operator=(scope_enable_fp_exceptions&&) = delete;

		fp_environment env;
	};

	//////////////////////////////////////////////////////////////////////////
	// Disables all floating point exceptions in the parent scope.
	//////////////////////////////////////////////////////////////////////////
	class scope_disable_fp_exceptions
	{
	public:
		scope_disable_fp_exceptions()
		{
			disable_fp_exceptions(env);
		}

		~scope_disable_fp_exceptions()
		{
			restore_fp_exceptions(env);
		}

	private:
		// Prevent copy or move
		scope_disable_fp_exceptions(const scope_disable_fp_exceptions&) = delete;
		scope_disable_fp_exceptions(scope_disable_fp_exceptions&&) = delete;
		scope_disable_fp_exceptions& operator=(const scope_disable_fp_exceptions&) = delete;
		scope_disable_fp_exceptions& operator=(scope_disable_fp_exceptions&&) = delete;

		fp_environment env;
	};
}

ACL_IMPL_FILE_PRAGMA_POP