smatz@8587: /* $Id$ */
skidd13@8433: 
smatz@8587: /** @file math_func.hpp Integer math functions */
skidd13@8433: 
skidd13@8433: #ifndef MATH_FUNC_HPP
skidd13@8433: #define MATH_FUNC_HPP
skidd13@8433: 
skidd13@8433: #ifdef min
skidd13@8433: #undef min
skidd13@8433: #endif
skidd13@8433: 
skidd13@8433: #ifdef max
skidd13@8433: #undef max
skidd13@8433: #endif
skidd13@8433: 
skidd13@8433: #ifdef abs
skidd13@8433: #undef abs
skidd13@8433: #endif
skidd13@8433: 
skidd13@8433: /**
skidd13@8433:  * Returns the maximum of two values.
skidd13@8433:  *
skidd13@8433:  * This function returns the greater value of two given values.
skidd13@8433:  * If they are equal the value of a is returned.
skidd13@8433:  *
skidd13@8433:  * @param a The first value
skidd13@8433:  * @param b The second value
skidd13@8433:  * @return The greater value or a if equals
skidd13@8433:  */
skidd13@8433: template<typename T> static inline T max(const T a, const T b)
skidd13@8433: {
skidd13@8433: 	return (a >= b) ? a : b;
skidd13@8433: }
skidd13@8433: 
skidd13@8433: /**
skidd13@8433:  * Returns the minimum of two values.
skidd13@8433:  *
skidd13@8433:  * This function returns the smaller value of two given values.
skidd13@8433:  * If they are equal the value of b is returned.
skidd13@8433:  *
skidd13@8433:  * @param a The first value
skidd13@8433:  * @param b The second value
skidd13@8433:  * @return The smaller value or b if equals
skidd13@8433:  */
skidd13@8433: template<typename T> static inline T min(const T a, const T b)
skidd13@8433: {
skidd13@8433: 	return (a < b) ? a : b;
skidd13@8433: }
skidd13@8433: 
skidd13@8433: /**
skidd13@8433:  * Returns the minimum of two integer.
skidd13@8433:  *
skidd13@8433:  * This function returns the smaller value of two given integers.
skidd13@8433:  *
skidd13@8433:  * @param a The first integer
skidd13@8433:  * @param b The second integer
skidd13@8433:  * @return The smaller value
skidd13@8433:  */
skidd13@8433: static inline int min(const int a, const int b)
skidd13@8433: {
skidd13@8433: 	return (a < b) ? a : b;
skidd13@8433: }
skidd13@8433: 
skidd13@8433: /**
skidd13@8433:  * Returns the minimum of two unsigned integers.
skidd13@8433:  *
skidd13@8433:  * This function returns the smaller value of two given unsigned integers.
skidd13@8433:  *
skidd13@8433:  * @param a The first unsigned integer
skidd13@8433:  * @param b The second unsigned integer
skidd13@8433:  * @return The smaller value
skidd13@8433:  */
skidd13@8433: static inline uint minu(const uint a, const uint b)
skidd13@8433: {
skidd13@8433: 	return (a < b) ? a : b;
skidd13@8433: }
skidd13@8433: 
skidd13@8433: /**
skidd13@8433:  * Returns the absolute value of (scalar) variable.
skidd13@8433:  *
skidd13@8433:  * @note assumes variable to be signed
skidd13@8433:  * @param a The value we want to unsign
skidd13@8433:  * @return The unsigned value
skidd13@8433:  */
skidd13@8450: template <typename T> static inline T abs(const T a)
skidd13@8433: {
skidd13@8433: 	return (a < (T)0) ? -a : a;
skidd13@8433: }
skidd13@8433: 
skidd13@8433: /**
skidd13@8433:  * Return the smallest multiple of n equal or greater than x
skidd13@8433:  *
skidd13@8433:  * @note n must be a power of 2
skidd13@8433:  * @param x The min value
skidd13@8433:  * @param n The base of the number we are searching
skidd13@8433:  * @return The smallest multiple of n equal or greater than x
skidd13@8433:  */
skidd13@8433: template<typename T> static inline T Align(const T x, uint n)
skidd13@8433: {
skidd13@8433: 	n--;
skidd13@8433: 	return (T)((x + n) & ~(n));
skidd13@8433: }
skidd13@8433: 
skidd13@8433: /**
skidd13@8433:  * Clamp an integer between an interval.
skidd13@8433:  *
skidd13@8433:  * This function returns a value which is between the given interval of
skidd13@8433:  * min and max. If the given value is in this interval the value itself
skidd13@8433:  * is returned otherwise the border of the interval is returned, according
skidd13@8433:  * which side of the interval was 'left'.
skidd13@8433:  *
skidd13@8433:  * @note The min value must be less or equal of max or you get some
skidd13@8433:  *       unexpected results.
skidd13@8433:  * @param a The value to clamp/truncate.
skidd13@8433:  * @param min The minimum of the interval.
skidd13@8433:  * @param max the maximum of the interval.
skidd13@8433:  * @returns A value between min and max which is closest to a.
skidd13@8433:  * @see ClampU(uint, uint, uint)
skidd13@8433:  */
skidd13@8433: static inline int Clamp(const int a, const int min, const int max)
skidd13@8433: {
skidd13@8433: 	if (a <= min) return min;
skidd13@8433: 	if (a >= max) return max;
skidd13@8433: 	return a;
skidd13@8433: }
skidd13@8433: 
skidd13@8433: /**
skidd13@8433:  * Clamp an unsigned integer between an interval.
skidd13@8433:  *
skidd13@8433:  * This function returns a value which is between the given interval of
skidd13@8433:  * min and max. If the given value is in this interval the value itself
skidd13@8433:  * is returned otherwise the border of the interval is returned, according
skidd13@8433:  * which side of the interval was 'left'.
skidd13@8433:  *
skidd13@8433:  * @note The min value must be less or equal of max or you get some
skidd13@8433:  *       unexpected results.
skidd13@8433:  * @param a The value to clamp/truncate.
skidd13@8433:  * @param min The minimum of the interval.
skidd13@8433:  * @param max the maximum of the interval.
skidd13@8433:  * @returns A value between min and max which is closest to a.
skidd13@8433:  * @see Clamp(int, int, int)
skidd13@8433:  */
skidd13@8433: static inline uint ClampU(const uint a, const uint min, const uint max)
skidd13@8433: {
skidd13@8433: 	if (a <= min) return min;
skidd13@8433: 	if (a >= max) return max;
skidd13@8433: 	return a;
skidd13@8433: }
skidd13@8433: 
skidd13@8433: /**
skidd13@8433:  * Reduce a signed 64-bit int to a signed 32-bit one
skidd13@8433:  *
skidd13@8433:  * This function clamps a 64-bit integer to a 32-bit integer.
skidd13@8433:  * If the 64-bit value is smaller than the smallest 32-bit integer
skidd13@8433:  * value 0x80000000 this value is returned (the left one bit is the sign bit).
skidd13@8433:  * If the 64-bit value is greater than the greatest 32-bit integer value 0x7FFFFFFF
skidd13@8433:  * this value is returned. In all other cases the 64-bit value 'fits' in a
skidd13@8433:  * 32-bits integer field and so the value is casted to int32 and returned.
skidd13@8433:  *
skidd13@8433:  * @param a The 64-bit value to clamps
skidd13@8433:  * @return The 64-bit value reduced to a 32-bit value
skidd13@8433:  * @see Clamp(int, int, int)
skidd13@8433:  */
skidd13@8433: static inline int32 ClampToI32(const int64 a)
skidd13@8433: {
skidd13@8433: 	if (a <= (int32)0x80000000) return 0x80000000;
skidd13@8433: 	if (a >= (int32)0x7FFFFFFF) return 0x7FFFFFFF;
skidd13@8433: 	return (int32)a;
skidd13@8433: }
skidd13@8433: 
skidd13@8433: /**
smatz@9106:  * Reduce an usigned 64-bit int to an unsigned 16-bit one
smatz@9106:  *
smatz@9106:  * @param a The 64-bit value to clamp
smatz@9106:  * @return The 64-bit value reduced to a 16-bit value
smatz@9106:  * @see ClampU(uint, uint, uint)
smatz@9106:  */
smatz@9106: static inline uint16 ClampToU16(const uint64 a)
smatz@9106: {
smatz@9117: 	return min(a, 0xFFFF);
smatz@9106: }
smatz@9106: 
smatz@9106: /**
skidd13@8433:  * Returns the (absolute) difference between two (scalar) variables
skidd13@8433:  *
skidd13@8433:  * @param a The first scalar
skidd13@8433:  * @param b The second scalar
skidd13@8433:  * @return The absolute difference between the given scalars
skidd13@8433:  */
skidd13@8466: template <typename T> static inline T Delta(const T a, const T b) {
skidd13@8433: 	return (a < b) ? b - a : a - b;
skidd13@8433: }
skidd13@8433: 
skidd13@8433: /**
skidd13@8433:  * Checks if a value is between a window started at some base point.
skidd13@8433:  *
skidd13@8433:  * This function checks if the value x is between the value of base
skidd13@8433:  * and base+size. If x equals base this returns true. If x equals
skidd13@8433:  * base+size this returns false.
skidd13@8433:  *
skidd13@8433:  * @param x The value to check
skidd13@8433:  * @param base The base value of the interval
skidd13@8433:  * @param size The size of the interval
skidd13@8433:  * @return True if the value is in the interval, false else.
skidd13@8433:  */
skidd13@8450: template<typename T> static inline bool IsInsideBS(const T x, const uint base, const uint size)
skidd13@8433: {
skidd13@8433: 	return (uint)(x - base) < size;
skidd13@8433: }
skidd13@8433: 
skidd13@8433: /**
skidd13@8450:  * Checks if a value is in an interval.
skidd13@8433:  *
skidd13@8450:  * Returns true if a value is in the interval of [min, max).
skidd13@8433:  *
skidd13@8450:  * @param a The value to check
skidd13@8433:  * @param min The minimum of the interval
skidd13@8433:  * @param max The maximum of the interval
skidd13@8450:  * @see IsInsideBS()
skidd13@8433:  */
skidd13@8450: template<typename T> static inline bool IsInsideMM(const T x, const uint min, const uint max)
skidd13@8433: {
skidd13@8433: 	return (uint)(x - min) < (max - min);
skidd13@8433: }
skidd13@8433: 
rubidium@8626: /**
rubidium@8626:  * Type safe swap operation
rubidium@8626:  * @param a variable to swap with b
rubidium@8626:  * @param b variable to swap with a
rubidium@8626:  */
rubidium@8626: template<typename T> void Swap(T& a, T& b)
rubidium@8626: {
rubidium@8626: 	T t = a;
rubidium@8626: 	a = b;
rubidium@8626: 	b = t;
rubidium@8626: }
rubidium@8626: 
skidd13@8433: #endif /* MATH_FUNC_HPP */