overflowsafe_type.hpp

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00001 /* $Id: overflowsafe_type.hpp 17248 2009-08-21 20:21:05Z rubidium $ */
00002 
00003 /*
00004  * This file is part of OpenTTD.
00005  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
00006  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
00007  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
00008  */
00009 
00012 #ifndef OVERFLOWSAFE_TYPE_HPP
00013 #define OVERFLOWSAFE_TYPE_HPP
00014 
00015 #include "math_func.hpp"
00016 
00025 template <class T, T T_MAX, T T_MIN>
00026 class OverflowSafeInt
00027 {
00028 private:
00030   T m_value;
00031 public:
00032   OverflowSafeInt() : m_value(0) { }
00033 
00034   OverflowSafeInt(const OverflowSafeInt& other) { this->m_value = other.m_value; }
00035   OverflowSafeInt(const int64 int_)             { this->m_value = int_; }
00036 
00037   FORCEINLINE OverflowSafeInt& operator = (const OverflowSafeInt& other) { this->m_value = other.m_value; return *this; }
00038 
00039   FORCEINLINE OverflowSafeInt operator - () const { return OverflowSafeInt(-this->m_value); }
00040 
00047   FORCEINLINE OverflowSafeInt& operator += (const OverflowSafeInt& other)
00048   {
00049     if ((T_MAX - abs(other.m_value)) < abs(this->m_value) &&
00050         (this->m_value < 0) == (other.m_value < 0)) {
00051       this->m_value = (this->m_value < 0) ? T_MIN : T_MAX ;
00052     } else {
00053       this->m_value += other.m_value;
00054     }
00055     return *this;
00056   }
00057 
00058   /* Operators for addition and substraction */
00059   FORCEINLINE OverflowSafeInt  operator +  (const OverflowSafeInt& other) const { OverflowSafeInt result = *this; result += other; return result; }
00060   FORCEINLINE OverflowSafeInt  operator +  (const int              other) const { OverflowSafeInt result = *this; result += (int64)other; return result; }
00061   FORCEINLINE OverflowSafeInt  operator +  (const uint             other) const { OverflowSafeInt result = *this; result += (int64)other; return result; }
00062   FORCEINLINE OverflowSafeInt& operator -= (const OverflowSafeInt& other)       { return *this += (-other); }
00063   FORCEINLINE OverflowSafeInt  operator -  (const OverflowSafeInt& other) const { OverflowSafeInt result = *this; result -= other; return result; }
00064   FORCEINLINE OverflowSafeInt  operator -  (const int              other) const { OverflowSafeInt result = *this; result -= (int64)other; return result; }
00065   FORCEINLINE OverflowSafeInt  operator -  (const uint             other) const { OverflowSafeInt result = *this; result -= (int64)other; return result; }
00066 
00067   FORCEINLINE OverflowSafeInt& operator ++ () { return *this += 1; }
00068   FORCEINLINE OverflowSafeInt& operator -- () { return *this += -1; }
00069   FORCEINLINE OverflowSafeInt operator ++ (int) { OverflowSafeInt org = *this; *this += 1; return org; }
00070   FORCEINLINE OverflowSafeInt operator -- (int) { OverflowSafeInt org = *this; *this += -1; return org; }
00071 
00078   FORCEINLINE OverflowSafeInt& operator *= (const int factor)
00079   {
00080     if (factor != 0 && (T_MAX / abs(factor)) < abs(this->m_value)) {
00081        this->m_value = ((this->m_value < 0) == (factor < 0)) ? T_MAX : T_MIN ;
00082     } else {
00083       this->m_value *= factor ;
00084     }
00085     return *this;
00086   }
00087 
00088   /* Operators for multiplication */
00089   FORCEINLINE OverflowSafeInt operator * (const int64  factor) const { OverflowSafeInt result = *this; result *= factor; return result; }
00090   FORCEINLINE OverflowSafeInt operator * (const int    factor) const { OverflowSafeInt result = *this; result *= (int64)factor; return result; }
00091   FORCEINLINE OverflowSafeInt operator * (const uint   factor) const { OverflowSafeInt result = *this; result *= (int64)factor; return result; }
00092   FORCEINLINE OverflowSafeInt operator * (const uint16 factor) const { OverflowSafeInt result = *this; result *= (int64)factor; return result; }
00093   FORCEINLINE OverflowSafeInt operator * (const byte   factor) const { OverflowSafeInt result = *this; result *= (int64)factor; return result; }
00094 
00095   /* Operators for division */
00096   FORCEINLINE OverflowSafeInt& operator /= (const int64            divisor)       { this->m_value /= divisor; return *this; }
00097   FORCEINLINE OverflowSafeInt  operator /  (const OverflowSafeInt& divisor) const { OverflowSafeInt result = *this; result /= divisor.m_value; return result; }
00098   FORCEINLINE OverflowSafeInt  operator /  (const int              divisor) const { OverflowSafeInt result = *this; result /= divisor; return result; }
00099   FORCEINLINE OverflowSafeInt  operator /  (const uint             divisor) const { OverflowSafeInt result = *this; result /= (int)divisor; return result; }
00100 
00101   /* Operators for modulo */
00102   FORCEINLINE OverflowSafeInt& operator %= (const int  divisor)       { this->m_value %= divisor; return *this; }
00103   FORCEINLINE OverflowSafeInt  operator %  (const int  divisor) const { OverflowSafeInt result = *this; result %= divisor; return result; }
00104 
00105   /* Operators for shifting */
00106   FORCEINLINE OverflowSafeInt& operator <<= (const int shift)       { this->m_value <<= shift; return *this; }
00107   FORCEINLINE OverflowSafeInt  operator <<  (const int shift) const { OverflowSafeInt result = *this; result <<= shift; return result; }
00108   FORCEINLINE OverflowSafeInt& operator >>= (const int shift)       { this->m_value >>= shift; return *this; }
00109   FORCEINLINE OverflowSafeInt  operator >>  (const int shift) const { OverflowSafeInt result = *this; result >>= shift; return result; }
00110 
00111   /* Operators for (in)equality when comparing overflow safe ints */
00112   FORCEINLINE bool operator == (const OverflowSafeInt& other) const { return this->m_value == other.m_value; }
00113   FORCEINLINE bool operator != (const OverflowSafeInt& other) const { return !(*this == other); }
00114   FORCEINLINE bool operator >  (const OverflowSafeInt& other) const { return this->m_value > other.m_value; }
00115   FORCEINLINE bool operator >= (const OverflowSafeInt& other) const { return this->m_value >= other.m_value; }
00116   FORCEINLINE bool operator <  (const OverflowSafeInt& other) const { return !(*this >= other); }
00117   FORCEINLINE bool operator <= (const OverflowSafeInt& other) const { return !(*this > other); }
00118 
00119   /* Operators for (in)equality when comparing non-overflow safe ints */
00120   FORCEINLINE bool operator == (const int other) const { return this->m_value == other; }
00121   FORCEINLINE bool operator != (const int other) const { return !(*this == other); }
00122   FORCEINLINE bool operator >  (const int other) const { return this->m_value > other; }
00123   FORCEINLINE bool operator >= (const int other) const { return this->m_value >= other; }
00124   FORCEINLINE bool operator <  (const int other) const { return !(*this >= other); }
00125   FORCEINLINE bool operator <= (const int other) const { return !(*this > other); }
00126 
00127   FORCEINLINE operator int64 () const { return this->m_value; }
00128 };
00129 
00130 /* Sometimes we got int64 operator OverflowSafeInt instead of vice versa. Handle that properly */
00131 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; }
00132 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; }
00133 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; }
00134 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; }
00135 
00136 /* Sometimes we got int operator OverflowSafeInt instead of vice versa. Handle that properly */
00137 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; }
00138 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; }
00139 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; }
00140 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; }
00141 
00142 /* Sometimes we got uint operator OverflowSafeInt instead of vice versa. Handle that properly */
00143 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; }
00144 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; }
00145 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; }
00146 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; }
00147 
00148 /* Sometimes we got byte operator OverflowSafeInt instead of vice versa. Handle that properly */
00149 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; }
00150 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; }
00151 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; }
00152 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; }
00153 
00154 typedef OverflowSafeInt<int64, INT64_MAX, INT64_MIN> OverflowSafeInt64;
00155 
00156 #endif /* OVERFLOWSAFE_TYPE_HPP */

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