1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
|
/*
* This file is part of OpenTTD.
* 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.
* 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.
* 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/>.
*/
/** @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 subtract something 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_; }
inline OverflowSafeInt& operator = (const OverflowSafeInt& other) { this->m_value = other.m_value; return *this; }
inline 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).
*/
inline 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 subtraction */
inline OverflowSafeInt operator + (const OverflowSafeInt& other) const { OverflowSafeInt result = *this; result += other; return result; }
inline OverflowSafeInt operator + (const int other) const { OverflowSafeInt result = *this; result += (int64)other; return result; }
inline OverflowSafeInt operator + (const uint other) const { OverflowSafeInt result = *this; result += (int64)other; return result; }
inline OverflowSafeInt& operator -= (const OverflowSafeInt& other) { return *this += (-other); }
inline OverflowSafeInt operator - (const OverflowSafeInt& other) const { OverflowSafeInt result = *this; result -= other; return result; }
inline OverflowSafeInt operator - (const int other) const { OverflowSafeInt result = *this; result -= (int64)other; return result; }
inline OverflowSafeInt operator - (const uint other) const { OverflowSafeInt result = *this; result -= (int64)other; return result; }
inline OverflowSafeInt& operator ++ () { return *this += 1; }
inline OverflowSafeInt& operator -- () { return *this += -1; }
inline OverflowSafeInt operator ++ (int) { OverflowSafeInt org = *this; *this += 1; return org; }
inline 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).
*/
inline 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 */
inline OverflowSafeInt operator * (const int64 factor) const { OverflowSafeInt result = *this; result *= factor; return result; }
inline OverflowSafeInt operator * (const int factor) const { OverflowSafeInt result = *this; result *= (int64)factor; return result; }
inline OverflowSafeInt operator * (const uint factor) const { OverflowSafeInt result = *this; result *= (int64)factor; return result; }
inline OverflowSafeInt operator * (const uint16 factor) const { OverflowSafeInt result = *this; result *= (int64)factor; return result; }
inline OverflowSafeInt operator * (const byte factor) const { OverflowSafeInt result = *this; result *= (int64)factor; return result; }
/* Operators for division */
inline OverflowSafeInt& operator /= (const int64 divisor) { this->m_value /= divisor; return *this; }
inline OverflowSafeInt operator / (const OverflowSafeInt& divisor) const { OverflowSafeInt result = *this; result /= divisor.m_value; return result; }
inline OverflowSafeInt operator / (const int divisor) const { OverflowSafeInt result = *this; result /= divisor; return result; }
inline OverflowSafeInt operator / (const uint divisor) const { OverflowSafeInt result = *this; result /= (int)divisor; return result; }
/* Operators for modulo */
inline OverflowSafeInt& operator %= (const int divisor) { this->m_value %= divisor; return *this; }
inline OverflowSafeInt operator % (const int divisor) const { OverflowSafeInt result = *this; result %= divisor; return result; }
/* Operators for shifting */
inline OverflowSafeInt& operator <<= (const int shift) { this->m_value <<= shift; return *this; }
inline OverflowSafeInt operator << (const int shift) const { OverflowSafeInt result = *this; result <<= shift; return result; }
inline OverflowSafeInt& operator >>= (const int shift) { this->m_value >>= shift; return *this; }
inline OverflowSafeInt operator >> (const int shift) const { OverflowSafeInt result = *this; result >>= shift; return result; }
/* Operators for (in)equality when comparing overflow safe ints */
inline bool operator == (const OverflowSafeInt& other) const { return this->m_value == other.m_value; }
inline bool operator != (const OverflowSafeInt& other) const { return !(*this == other); }
inline bool operator > (const OverflowSafeInt& other) const { return this->m_value > other.m_value; }
inline bool operator >= (const OverflowSafeInt& other) const { return this->m_value >= other.m_value; }
inline bool operator < (const OverflowSafeInt& other) const { return !(*this >= other); }
inline bool operator <= (const OverflowSafeInt& other) const { return !(*this > other); }
/* Operators for (in)equality when comparing non-overflow safe ints */
inline bool operator == (const int other) const { return this->m_value == other; }
inline bool operator != (const int other) const { return !(*this == other); }
inline bool operator > (const int other) const { return this->m_value > other; }
inline bool operator >= (const int other) const { return this->m_value >= other; }
inline bool operator < (const int other) const { return !(*this >= other); }
inline bool operator <= (const int other) const { return !(*this > other); }
inline 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> inline 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> inline 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> inline 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> 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; }
/* Sometimes we got int operator OverflowSafeInt instead of vice versa. Handle that properly */
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; }
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; }
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; }
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; }
/* Sometimes we got uint operator OverflowSafeInt instead of vice versa. Handle that properly */
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; }
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; }
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; }
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; }
/* Sometimes we got byte operator OverflowSafeInt instead of vice versa. Handle that properly */
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; }
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; }
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; }
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; }
typedef OverflowSafeInt<int64, INT64_MAX, INT64_MIN> OverflowSafeInt64;
typedef OverflowSafeInt<int32, INT32_MAX, INT32_MIN> OverflowSafeInt32;
#endif /* OVERFLOWSAFE_TYPE_HPP */
|
