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overflowsafe_type.hpp
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1 /* $Id: overflowsafe_type.hpp 26685 2014-07-12 17:04:14Z alberth $ */
2
3 /*
4 * This file is part of OpenTTD.
5 * 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.
6 * 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.
7 * 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/>.
8 */
9
12 #ifndef OVERFLOWSAFE_TYPE_HPP
13 #define OVERFLOWSAFE_TYPE_HPP
14
15 #include "math_func.hpp"
16
25 template <class T, T T_MAX, T T_MIN>
26 class OverflowSafeInt
27 {
28 private:
30 T m_value;
31 public:
32 OverflowSafeInt() : m_value(0) { }
33
34 OverflowSafeInt(const OverflowSafeInt& other) { this->m_value = other.m_value; }
35 OverflowSafeInt(const int64 int_) { this->m_value = int_; }
36
37 inline OverflowSafeInt& operator = (const OverflowSafeInt& other) { this->m_value = other.m_value; return *this; }
38
39 inline OverflowSafeInt operator - () const { return OverflowSafeInt(-this->m_value); }
40
47 inline OverflowSafeInt& operator += (const OverflowSafeInt& other)
48 {
49 if ((T_MAX - abs(other.m_value)) < abs(this->m_value) &&
50 (this->m_value < 0) == (other.m_value < 0)) {
51 this->m_value = (this->m_value < 0) ? T_MIN : T_MAX ;
52 } else {
53 this->m_value += other.m_value;
54 }
55 return *this;
56 }
57
58 /* Operators for addition and subtraction */
59 inline OverflowSafeInt operator + (const OverflowSafeInt& other) const { OverflowSafeInt result = *this; result += other; return result; }
60 inline OverflowSafeInt operator + (const int other) const { OverflowSafeInt result = *this; result += (int64)other; return result; }
61 inline OverflowSafeInt operator + (const uint other) const { OverflowSafeInt result = *this; result += (int64)other; return result; }
62 inline OverflowSafeInt& operator -= (const OverflowSafeInt& other) { return *this += (-other); }
63 inline OverflowSafeInt operator - (const OverflowSafeInt& other) const { OverflowSafeInt result = *this; result -= other; return result; }
64 inline OverflowSafeInt operator - (const int other) const { OverflowSafeInt result = *this; result -= (int64)other; return result; }
65 inline OverflowSafeInt operator - (const uint other) const { OverflowSafeInt result = *this; result -= (int64)other; return result; }
66
67 inline OverflowSafeInt& operator ++ () { return *this += 1; }
68 inline OverflowSafeInt& operator -- () { return *this += -1; }
69 inline OverflowSafeInt operator ++ (int) { OverflowSafeInt org = *this; *this += 1; return org; }
70 inline OverflowSafeInt operator -- (int) { OverflowSafeInt org = *this; *this += -1; return org; }
71
78 inline OverflowSafeInt& operator *= (const int factor)
79 {
80 if (factor != 0 && (T_MAX / abs(factor)) < abs(this->m_value)) {
81 this->m_value = ((this->m_value < 0) == (factor < 0)) ? T_MAX : T_MIN ;
82 } else {
83 this->m_value *= factor ;
84 }
85 return *this;
86 }
87
88 /* Operators for multiplication */
89 inline OverflowSafeInt operator * (const int64 factor) const { OverflowSafeInt result = *this; result *= factor; return result; }
90 inline OverflowSafeInt operator * (const int factor) const { OverflowSafeInt result = *this; result *= (int64)factor; return result; }
91 inline OverflowSafeInt operator * (const uint factor) const { OverflowSafeInt result = *this; result *= (int64)factor; return result; }
92 inline OverflowSafeInt operator * (const uint16 factor) const { OverflowSafeInt result = *this; result *= (int64)factor; return result; }
93 inline OverflowSafeInt operator * (const byte factor) const { OverflowSafeInt result = *this; result *= (int64)factor; return result; }
94
95 /* Operators for division */
96 inline OverflowSafeInt& operator /= (const int64 divisor) { this->m_value /= divisor; return *this; }
97 inline OverflowSafeInt operator / (const OverflowSafeInt& divisor) const { OverflowSafeInt result = *this; result /= divisor.m_value; return result; }
98 inline OverflowSafeInt operator / (const int divisor) const { OverflowSafeInt result = *this; result /= divisor; return result; }
99 inline OverflowSafeInt operator / (const uint divisor) const { OverflowSafeInt result = *this; result /= (int)divisor; return result; }
100
101 /* Operators for modulo */
102 inline OverflowSafeInt& operator %= (const int divisor) { this->m_value %= divisor; return *this; }
103 inline OverflowSafeInt operator % (const int divisor) const { OverflowSafeInt result = *this; result %= divisor; return result; }
104
105 /* Operators for shifting */
106 inline OverflowSafeInt& operator <<= (const int shift) { this->m_value <<= shift; return *this; }
107 inline OverflowSafeInt operator << (const int shift) const { OverflowSafeInt result = *this; result <<= shift; return result; }
108 inline OverflowSafeInt& operator >>= (const int shift) { this->m_value >>= shift; return *this; }
109 inline OverflowSafeInt operator >> (const int shift) const { OverflowSafeInt result = *this; result >>= shift; return result; }
110
111 /* Operators for (in)equality when comparing overflow safe ints */
112 inline bool operator == (const OverflowSafeInt& other) const { return this->m_value == other.m_value; }
113 inline bool operator != (const OverflowSafeInt& other) const { return !(*this == other); }
114 inline bool operator > (const OverflowSafeInt& other) const { return this->m_value > other.m_value; }
115 inline bool operator >= (const OverflowSafeInt& other) const { return this->m_value >= other.m_value; }
116 inline bool operator < (const OverflowSafeInt& other) const { return !(*this >= other); }
117 inline bool operator <= (const OverflowSafeInt& other) const { return !(*this > other); }
118
119 /* Operators for (in)equality when comparing non-overflow safe ints */
120 inline bool operator == (const int other) const { return this->m_value == other; }
121 inline bool operator != (const int other) const { return !(*this == other); }
122 inline bool operator > (const int other) const { return this->m_value > other; }
123 inline bool operator >= (const int other) const { return this->m_value >= other; }
124 inline bool operator < (const int other) const { return !(*this >= other); }
125 inline bool operator <= (const int other) const { return !(*this > other); }
126
127 inline operator int64 () const { return this->m_value; }
128 };
129
130 /* Sometimes we got int64 operator OverflowSafeInt instead of vice versa. Handle that properly */
131 template <class T, int64 T_MAX, int64 T_MIN> inline OverflowSafeInt<T, T_MAX, T_MIN> operator + (int64 a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b + a; }
132 template <class T, int64 T_MAX, int64 T_MIN> inline OverflowSafeInt<T, T_MAX, T_MIN> operator - (int64 a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return -b + a; }
133 template <class T, int64 T_MAX, int64 T_MIN> inline OverflowSafeInt<T, T_MAX, T_MIN> operator * (int64 a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b * a; }
134 template <class T, int64 T_MAX, int64 T_MIN> inline 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; }
135
136 /* Sometimes we got int operator OverflowSafeInt instead of vice versa. Handle that properly */
137 template <class T, int64 T_MAX, int64 T_MIN> inline OverflowSafeInt<T, T_MAX, T_MIN> operator + (int a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b + a; }
138 template <class T, int64 T_MAX, int64 T_MIN> inline OverflowSafeInt<T, T_MAX, T_MIN> operator - (int a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return -b + a; }
139 template <class T, int64 T_MAX, int64 T_MIN> inline OverflowSafeInt<T, T_MAX, T_MIN> operator * (int a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b * a; }
140 template <class T, int64 T_MAX, int64 T_MIN> inline 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; }
141
142 /* Sometimes we got uint operator OverflowSafeInt instead of vice versa. Handle that properly */
143 template <class T, int64 T_MAX, int64 T_MIN> inline OverflowSafeInt<T, T_MAX, T_MIN> operator + (uint a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b + a; }
144 template <class T, int64 T_MAX, int64 T_MIN> inline OverflowSafeInt<T, T_MAX, T_MIN> operator - (uint a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return -b + a; }
145 template <class T, int64 T_MAX, int64 T_MIN> inline OverflowSafeInt<T, T_MAX, T_MIN> operator * (uint a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b * a; }
146 template <class T, int64 T_MAX, int64 T_MIN> inline 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; }
147
148 /* Sometimes we got byte operator OverflowSafeInt instead of vice versa. Handle that properly */
149 template <class T, int64 T_MAX, int64 T_MIN> inline OverflowSafeInt<T, T_MAX, T_MIN> operator + (byte a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b + (uint)a; }
150 template <class T, int64 T_MAX, int64 T_MIN> inline OverflowSafeInt<T, T_MAX, T_MIN> operator - (byte a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return -b + (uint)a; }
151 template <class T, int64 T_MAX, int64 T_MIN> inline OverflowSafeInt<T, T_MAX, T_MIN> operator * (byte a, OverflowSafeInt<T, T_MAX, T_MIN> b) { return b * (uint)a; }
152 template <class T, int64 T_MAX, int64 T_MIN> inline 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; }
153
154 typedef OverflowSafeInt<int64, INT64_MAX, INT64_MIN> OverflowSafeInt64;
155 typedef OverflowSafeInt<int32, INT32_MAX, INT32_MIN> OverflowSafeInt32;
156
157 #endif /* OVERFLOWSAFE_TYPE_HPP */