Initial community commit

Src/external_dependencies/openmpt-trunk/common/mptBaseUtils.h

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+/*
+ * mptBaseUtils.h
+ * --------------
+ * Purpose: Various useful utility functions.
+ * Notes  : (currently none)
+ * Authors: OpenMPT Devs
+ * The OpenMPT source code is released under the BSD license. Read LICENSE for more details.
+ */
+
+
+#pragma once
+
+#include "openmpt/all/BuildSettings.hpp"
+
+
+#include "mpt/base/algorithm.hpp"
+#include "mpt/base/arithmetic_shift.hpp"
+#include "mpt/base/array.hpp"
+#include "mpt/base/bit.hpp"
+#include "mpt/base/constexpr_throw.hpp"
+#include "mpt/base/math.hpp"
+#include "mpt/base/memory.hpp"
+#include "mpt/base/numeric.hpp"
+#include "mpt/base/saturate_cast.hpp"
+#include "mpt/base/saturate_round.hpp"
+#include "mpt/base/utility.hpp"
+#include "mpt/base/wrapping_divide.hpp"
+
+#include "mptBaseMacros.h"
+#include "mptBaseTypes.h"
+
+#include <algorithm>
+#include <limits>
+#include <numeric>
+#include <utility>
+
+#include <cmath>
+#include <cstdlib>
+
+#include <math.h>
+#include <stdlib.h>
+
+#if MPT_COMPILER_MSVC
+#include <intrin.h>
+#endif
+
+
+
+OPENMPT_NAMESPACE_BEGIN
+
+
+
+template <typename T>
+inline void Clear(T& x)
+{
+	static_assert(!std::is_pointer<T>::value);
+	mpt::reset(x);
+}
+
+
+// Memset given object to zero.
+template <class T>
+inline void MemsetZero(T& a)
+{
+	static_assert(std::is_pointer<T>::value == false, "Won't memset pointers.");
+	mpt::memclear(a);
+}
+
+
+
+// Limits 'val' to given range. If 'val' is less than 'lowerLimit', 'val' is set to value 'lowerLimit'.
+// Similarly if 'val' is greater than 'upperLimit', 'val' is set to value 'upperLimit'.
+// If 'lowerLimit' > 'upperLimit', 'val' won't be modified.
+template<class T, class C>
+inline void Limit(T& val, const C lowerLimit, const C upperLimit)
+{
+	if(lowerLimit > upperLimit) return;
+	if(val < lowerLimit) val = lowerLimit;
+	else if(val > upperLimit) val = upperLimit;
+}
+
+
+// Like Limit, but returns value
+template<class T, class C>
+inline T Clamp(T val, const C lowerLimit, const C upperLimit)
+{
+	if(val < lowerLimit) return lowerLimit;
+	else if(val > upperLimit) return upperLimit;
+	else return val;
+}
+
+// Like Limit, but with upperlimit only.
+template<class T, class C>
+inline void LimitMax(T& val, const C upperLimit)
+{
+	if(val > upperLimit)
+		val = upperLimit;
+}
+
+
+
+namespace Util
+{
+
+	// Returns maximum value of given integer type.
+	template <class T> constexpr T MaxValueOfType(const T&) {static_assert(std::numeric_limits<T>::is_integer == true, "Only integer types are allowed."); return (std::numeric_limits<T>::max)();}
+
+}  // namespace Util
+
+
+
+namespace Util {
+
+	// Multiply two 32-bit integers, receive 64-bit result.
+	// MSVC generates unnecessarily complicated code for the unoptimized variant using _allmul.
+	MPT_CONSTEXPR20_FUN int64 mul32to64(int32 a, int32 b)
+	{
+		#if MPT_COMPILER_MSVC && (defined(_M_IX86) || defined(_M_X64))
+			MPT_MAYBE_CONSTANT_IF(MPT_IS_CONSTANT_EVALUATED20())
+			{
+				return static_cast<int64>(a) * b;
+			} else
+			{
+				return __emul(a, b);
+			}
+		#else
+			return static_cast<int64>(a) * b;
+		#endif
+	}
+
+	MPT_CONSTEXPR20_FUN uint64 mul32to64_unsigned(uint32 a, uint32 b)
+	{
+		#if MPT_COMPILER_MSVC && (defined(_M_IX86) || defined(_M_X64))
+			MPT_MAYBE_CONSTANT_IF(MPT_IS_CONSTANT_EVALUATED20())
+			{
+				return static_cast<uint64>(a) * b;
+			} else
+			{
+				return __emulu(a, b);
+			}
+		#else
+			return static_cast<uint64>(a) * b;
+		#endif
+	}
+
+	MPT_CONSTEXPR20_FUN int32 muldiv(int32 a, int32 b, int32 c)
+	{
+		return mpt::saturate_cast<int32>( mul32to64( a, b ) / c );
+	}
+
+	MPT_CONSTEXPR20_FUN int32 muldivr(int32 a, int32 b, int32 c)
+	{
+		return mpt::saturate_cast<int32>( ( mul32to64( a, b ) + ( c / 2 ) ) / c );
+	}
+
+	// Do not use overloading because catching unsigned version by accident results in slower X86 code.
+	MPT_CONSTEXPR20_FUN uint32 muldiv_unsigned(uint32 a, uint32 b, uint32 c)
+	{
+		return mpt::saturate_cast<uint32>( mul32to64_unsigned( a, b ) / c );
+	}
+	MPT_CONSTEXPR20_FUN uint32 muldivr_unsigned(uint32 a, uint32 b, uint32 c)
+	{
+		return mpt::saturate_cast<uint32>( ( mul32to64_unsigned( a, b ) + ( c / 2u ) ) / c );
+	}
+
+	constexpr MPT_FORCEINLINE int32 muldivrfloor(int64 a, uint32 b, uint32 c)
+	{
+		a *= b;
+		a += c / 2u;
+		return (a >= 0) ? mpt::saturate_cast<int32>(a / c) : mpt::saturate_cast<int32>((a - (c - 1)) / c);
+	}
+
+} // namespace Util
+
+
+
+OPENMPT_NAMESPACE_END