rubidium@5587: /* $Id$ */
rubidium@5587: 
rubidium@8112: /** @file overflowsafe_type.hpp An overflow safe integer-like type. */
rubidium@5587: 
rubidium@8112: #ifndef OVERFLOWSAFE_TYPE_HPP
rubidium@8112: #define OVERFLOWSAFE_TYPE_HPP
rubidium@5587: 
rubidium@8113: #include "math_func.hpp"
rubidium@8113: 
rubidium@7763: /**
rubidium@7763:  * Overflow safe template for integers, i.e. integers that will never overflow
rubidium@7763:  * you multiply the maximum value with 2, or add 2, or substract somethng from
rubidium@7763:  * the minimum value, etc.
rubidium@7763:  * @param T     the type these integers are stored with.
rubidium@7763:  * @param T_MAX the maximum value for the integers.
rubidium@7763:  * @param T_MIN the minimum value for the integers.
rubidium@7763:  */
rubidium@7763: template <class T, T T_MAX, T T_MIN>
rubidium@7763: class OverflowSafeInt
rubidium@7763: {
rubidium@7763: private:
rubidium@7763: 	/** The non-overflow safe backend to store the value in. */
rubidium@7763: 	T m_value;
rubidium@7763: public:
rubidium@7763: 	OverflowSafeInt() : m_value(0) { }
rubidium@7763: 
rubidium@7763: 	OverflowSafeInt(const OverflowSafeInt& other) { this->m_value = other.m_value; }
rubidium@7763: 	OverflowSafeInt(const int64 int_)             { this->m_value = int_; }
rubidium@7763: 
rubidium@7763: 	FORCEINLINE OverflowSafeInt& operator = (const OverflowSafeInt& other) { this->m_value = other.m_value; return *this; }
rubidium@7763: 
rubidium@7763: 	FORCEINLINE OverflowSafeInt operator - () const { return OverflowSafeInt(-this->m_value); }
rubidium@7763: 
rubidium@7763: 	/**
rubidium@7763: 	 * Safe implementation of addition.
rubidium@7763: 	 * @param other the amount to add
rubidium@7763: 	 * @note when the addition would yield more than T_MAX (or less than T_MIN),
rubidium@7763: 	 *       it will be T_MAX (respectively T_MIN).
rubidium@7763: 	 */
rubidium@7763: 	FORCEINLINE OverflowSafeInt& operator += (const OverflowSafeInt& other)
rubidium@7763: 	{
skidd13@7923: 		if ((T_MAX - abs(other.m_value)) < abs(this->m_value) &&
rubidium@7763: 				(this->m_value < 0) == (other.m_value < 0)) {
rubidium@7763: 			this->m_value = (this->m_value < 0) ? T_MIN : T_MAX ;
rubidium@7763: 		} else {
rubidium@7763: 			this->m_value += other.m_value;
rubidium@7763: 		}
rubidium@7763: 		return *this;
rubidium@7763: 	}
rubidium@7763: 
rubidium@7763: 	/* Operators for addition and substraction */
rubidium@7763: 	FORCEINLINE OverflowSafeInt  operator +  (const OverflowSafeInt& other) const { OverflowSafeInt result = *this; result += other; return result; }
rubidium@7763: 	FORCEINLINE OverflowSafeInt  operator +  (const int              other) const { OverflowSafeInt result = *this; result += (int64)other; return result; }
rubidium@7763: 	FORCEINLINE OverflowSafeInt  operator +  (const uint             other) const { OverflowSafeInt result = *this; result += (int64)other; return result; }
rubidium@7763: 	FORCEINLINE OverflowSafeInt& operator -= (const OverflowSafeInt& other)       { return *this += (-other); }
rubidium@7763: 	FORCEINLINE OverflowSafeInt  operator -  (const OverflowSafeInt& other) const { OverflowSafeInt result = *this; result -= other; return result; }
rubidium@7763: 	FORCEINLINE OverflowSafeInt  operator -  (const int              other) const { OverflowSafeInt result = *this; result -= (int64)other; return result; }
rubidium@7763: 	FORCEINLINE OverflowSafeInt  operator -  (const uint             other) const { OverflowSafeInt result = *this; result -= (int64)other; return result; }
rubidium@7763: 
truelight@7838: 	FORCEINLINE OverflowSafeInt& operator ++ () { return *this += 1; }
truelight@7838: 	FORCEINLINE OverflowSafeInt& operator -- () { return *this += -1; }
truelight@7838: 	FORCEINLINE OverflowSafeInt operator ++ (int) { OverflowSafeInt org = *this; *this += 1; return org; }
truelight@7838: 	FORCEINLINE OverflowSafeInt operator -- (int) { OverflowSafeInt org = *this; *this += -1; return org; }
rubidium@7763: 
rubidium@7763: 	/**
rubidium@7763: 	 * Safe implementation of multiplication.
rubidium@7763: 	 * @param factor the factor to multiply this with.
rubidium@7763: 	 * @note when the multiplication would yield more than T_MAX (or less than T_MIN),
rubidium@7763: 	 *       it will be T_MAX (respectively T_MIN).
rubidium@7763: 	 */
rubidium@7763: 	FORCEINLINE OverflowSafeInt& operator *= (const int factor)
rubidium@7763: 	{
skidd13@7923: 		if (factor != 0 && (T_MAX / abs(factor)) < abs(this->m_value)) {
rubidium@7763: 			 this->m_value = ((this->m_value < 0) == (factor < 0)) ? T_MAX : T_MIN ;
rubidium@7763: 		} else {
rubidium@7763: 			this->m_value *= factor ;
rubidium@7763: 		}
rubidium@7763: 		return *this;
rubidium@7763: 	}
rubidium@7763: 
rubidium@7763: 	/* Operators for multiplication */
rubidium@7763: 	FORCEINLINE OverflowSafeInt operator * (const int64  factor) const { OverflowSafeInt result = *this; result *= factor; return result; }
rubidium@7763: 	FORCEINLINE OverflowSafeInt operator * (const int    factor) const { OverflowSafeInt result = *this; result *= (int64)factor; return result; }
rubidium@7763: 	FORCEINLINE OverflowSafeInt operator * (const uint   factor) const { OverflowSafeInt result = *this; result *= (int64)factor; return result; }
rubidium@7763: 	FORCEINLINE OverflowSafeInt operator * (const uint16 factor) const { OverflowSafeInt result = *this; result *= (int64)factor; return result; }
rubidium@7763: 	FORCEINLINE OverflowSafeInt operator * (const byte   factor) const { OverflowSafeInt result = *this; result *= (int64)factor; return result; }
rubidium@7763: 
rubidium@7763: 	/* Operators for division */
rubidium@7763: 	FORCEINLINE OverflowSafeInt& operator /= (const int              divisor)       { this->m_value /= divisor; return *this; }
rubidium@7763: 	FORCEINLINE OverflowSafeInt  operator /  (const OverflowSafeInt& divisor) const { OverflowSafeInt result = *this; result /= divisor.m_value; return result; }
rubidium@7763: 	FORCEINLINE OverflowSafeInt  operator /  (const int              divisor) const { OverflowSafeInt result = *this; result /= divisor; return result; }
rubidium@7763: 	FORCEINLINE OverflowSafeInt  operator /  (const uint             divisor) const { OverflowSafeInt result = *this; result /= (int)divisor; return result; }
rubidium@7763: 
rubidium@7763: 	/* Operators for modulo */
rubidium@7763: 	FORCEINLINE OverflowSafeInt& operator %= (const int  divisor)       { this->m_value %= divisor; return *this; }
rubidium@7763: 	FORCEINLINE OverflowSafeInt  operator %  (const int  divisor) const { OverflowSafeInt result = *this; result %= divisor; return result; }
rubidium@7763: 
rubidium@7763: 	/* Operators for shifting */
rubidium@7763: 	FORCEINLINE OverflowSafeInt& operator <<= (const int shift)       { this->m_value <<= shift; return *this; }
rubidium@7763: 	FORCEINLINE OverflowSafeInt  operator <<  (const int shift) const { OverflowSafeInt result = *this; result <<= shift; return result; }
rubidium@7763: 	FORCEINLINE OverflowSafeInt& operator >>= (const int shift)       { this->m_value >>= shift; return *this; }
rubidium@7763: 	FORCEINLINE OverflowSafeInt  operator >>  (const int shift) const { OverflowSafeInt result = *this; result >>= shift; return result; }
rubidium@7763: 
rubidium@7763: 	/* Operators for (in)equality when comparing overflow safe ints */
rubidium@7763: 	FORCEINLINE bool operator == (const OverflowSafeInt& other) const { return this->m_value == other.m_value; }
rubidium@7763: 	FORCEINLINE bool operator != (const OverflowSafeInt& other) const { return !(*this == other); }
rubidium@7763: 	FORCEINLINE bool operator >  (const OverflowSafeInt& other) const { return this->m_value > other.m_value; }
rubidium@7763: 	FORCEINLINE bool operator >= (const OverflowSafeInt& other) const { return this->m_value >= other.m_value; }
rubidium@7763: 	FORCEINLINE bool operator <  (const OverflowSafeInt& other) const { return !(*this >= other); }
rubidium@7763: 	FORCEINLINE bool operator <= (const OverflowSafeInt& other) const { return !(*this > other); }
rubidium@7763: 
rubidium@7763: 	/* Operators for (in)equality when comparing non-overflow safe ints */
rubidium@7763: 	FORCEINLINE bool operator == (const int other) const { return this->m_value == other; }
rubidium@7763: 	FORCEINLINE bool operator != (const int other) const { return !(*this == other); }
rubidium@7763: 	FORCEINLINE bool operator >  (const int other) const { return this->m_value > other; }
rubidium@7763: 	FORCEINLINE bool operator >= (const int other) const { return this->m_value >= other; }
rubidium@7763: 	FORCEINLINE bool operator <  (const int other) const { return !(*this >= other); }
rubidium@7763: 	FORCEINLINE bool operator <= (const int other) const { return !(*this > other); }
rubidium@7763: 
rubidium@7763: 	FORCEINLINE operator int64 () const { return this->m_value; }
rubidium@7763: };
rubidium@7763: 
rubidium@7763: /* Sometimes we got int64 operator OverflowSafeInt instead of vice versa. Handle that properly */
rubidium@7763: template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator + (int64 a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b + a; }
rubidium@7763: template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator - (int64 a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return -b + a; }
rubidium@7763: template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator * (int64 a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b * a; }
rubidium@7763: template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator / (int64 a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return (OverflowSafeInt<T, T_MAX, T_MIN>)a / (int)b; }
rubidium@7763: 
rubidium@7763: /* Sometimes we got int operator OverflowSafeInt instead of vice versa. Handle that properly */
rubidium@7763: template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator + (int   a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b + a; }
rubidium@7763: template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator - (int   a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return -b + a; }
rubidium@7763: template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator * (int   a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b * a; }
rubidium@7763: template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator / (int   a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return (OverflowSafeInt<T, T_MAX, T_MIN>)a / (int)b; }
rubidium@7763: 
rubidium@7763: /* Sometimes we got uint operator OverflowSafeInt instead of vice versa. Handle that properly */
rubidium@7763: template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator + (uint  a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b + a; }
rubidium@7763: template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator - (uint  a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return -b + a; }
rubidium@7763: template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator * (uint  a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b * a; }
rubidium@7763: template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator / (uint  a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return (OverflowSafeInt<T, T_MAX, T_MIN>)a / (int)b; }
rubidium@7763: 
rubidium@7763: /* Sometimes we got byte operator OverflowSafeInt instead of vice versa. Handle that properly */
rubidium@9047: template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator + (byte  a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b + (uint)a; }
rubidium@9047: template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator - (byte  a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return -b + (uint)a; }
rubidium@9047: template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator * (byte  a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b * (uint)a; }
rubidium@7763: template <class T, int64 T_MAX, int64 T_MIN> FORCEINLINE OverflowSafeInt<T, T_MAX, T_MIN> operator / (byte  a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return (OverflowSafeInt<T, T_MAX, T_MIN>)a / (int)b; }
rubidium@7763: 
rubidium@8112: typedef OverflowSafeInt<int64, INT64_MAX, INT64_MIN> OverflowSafeInt64;
rubidium@8112: 
rubidium@8112: #endif /* OVERFLOWSAFE_TYPE_HPP */