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