num-traits 0.2.0

Numeric traits for generic mathematics
Documentation 
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
156
157
158
159
160
161
162

use core::ops::{Add, Sub, Mul, Div, Shl, Shr};

/// Performs addition that returns `None` instead of wrapping around on
/// overflow.
pub trait CheckedAdd: Sized + Add<Self, Output=Self> {
    /// Adds two numbers, checking for overflow. If overflow happens, `None` is
    /// returned.
    fn checked_add(&self, v: &Self) -> Option<Self>;
}

macro_rules! checked_impl {
    ($trait_name:ident, $method:ident, $t:ty) => {
        impl $trait_name for $t {
            #[inline]
            fn $method(&self, v: &$t) -> Option<$t> {
                <$t>::$method(*self, *v)
            }
        }
    }
}

checked_impl!(CheckedAdd, checked_add, u8);
checked_impl!(CheckedAdd, checked_add, u16);
checked_impl!(CheckedAdd, checked_add, u32);
checked_impl!(CheckedAdd, checked_add, u64);
checked_impl!(CheckedAdd, checked_add, usize);

checked_impl!(CheckedAdd, checked_add, i8);
checked_impl!(CheckedAdd, checked_add, i16);
checked_impl!(CheckedAdd, checked_add, i32);
checked_impl!(CheckedAdd, checked_add, i64);
checked_impl!(CheckedAdd, checked_add, isize);

/// Performs subtraction that returns `None` instead of wrapping around on underflow.
pub trait CheckedSub: Sized + Sub<Self, Output=Self> {
    /// Subtracts two numbers, checking for underflow. If underflow happens,
    /// `None` is returned.
    fn checked_sub(&self, v: &Self) -> Option<Self>;
}

checked_impl!(CheckedSub, checked_sub, u8);
checked_impl!(CheckedSub, checked_sub, u16);
checked_impl!(CheckedSub, checked_sub, u32);
checked_impl!(CheckedSub, checked_sub, u64);
checked_impl!(CheckedSub, checked_sub, usize);

checked_impl!(CheckedSub, checked_sub, i8);
checked_impl!(CheckedSub, checked_sub, i16);
checked_impl!(CheckedSub, checked_sub, i32);
checked_impl!(CheckedSub, checked_sub, i64);
checked_impl!(CheckedSub, checked_sub, isize);

/// Performs multiplication that returns `None` instead of wrapping around on underflow or
/// overflow.
pub trait CheckedMul: Sized + Mul<Self, Output=Self> {
    /// Multiplies two numbers, checking for underflow or overflow. If underflow
    /// or overflow happens, `None` is returned.
    fn checked_mul(&self, v: &Self) -> Option<Self>;
}

checked_impl!(CheckedMul, checked_mul, u8);
checked_impl!(CheckedMul, checked_mul, u16);
checked_impl!(CheckedMul, checked_mul, u32);
checked_impl!(CheckedMul, checked_mul, u64);
checked_impl!(CheckedMul, checked_mul, usize);

checked_impl!(CheckedMul, checked_mul, i8);
checked_impl!(CheckedMul, checked_mul, i16);
checked_impl!(CheckedMul, checked_mul, i32);
checked_impl!(CheckedMul, checked_mul, i64);
checked_impl!(CheckedMul, checked_mul, isize);

/// Performs division that returns `None` instead of panicking on division by zero and instead of
/// wrapping around on underflow and overflow.
pub trait CheckedDiv: Sized + Div<Self, Output=Self> {
    /// Divides two numbers, checking for underflow, overflow and division by
    /// zero. If any of that happens, `None` is returned.
    fn checked_div(&self, v: &Self) -> Option<Self>;
}

checked_impl!(CheckedDiv, checked_div, u8);
checked_impl!(CheckedDiv, checked_div, u16);
checked_impl!(CheckedDiv, checked_div, u32);
checked_impl!(CheckedDiv, checked_div, u64);
checked_impl!(CheckedDiv, checked_div, usize);

checked_impl!(CheckedDiv, checked_div, i8);
checked_impl!(CheckedDiv, checked_div, i16);
checked_impl!(CheckedDiv, checked_div, i32);
checked_impl!(CheckedDiv, checked_div, i64);
checked_impl!(CheckedDiv, checked_div, isize);

/// Performs a left shift that returns `None` on overflow.
pub trait CheckedShl: Sized + Shl<u32, Output=Self> {
    /// Shifts a number to the left, checking for overflow. If overflow happens,
    /// `None` is returned.
    ///
    /// ```
    /// use num_traits::CheckedShl;
    ///
    /// let x: u16 = 0x0001;
    ///
    /// assert_eq!(CheckedShl::checked_shl(&x, 0),  Some(0x0001));
    /// assert_eq!(CheckedShl::checked_shl(&x, 1),  Some(0x0002));
    /// assert_eq!(CheckedShl::checked_shl(&x, 15), Some(0x8000));
    /// assert_eq!(CheckedShl::checked_shl(&x, 16), None);
    /// ```
    fn checked_shl(&self, rhs: u32) -> Option<Self>;
}

macro_rules! checked_shift_impl {
    ($trait_name:ident, $method:ident, $t:ty) => {
        impl $trait_name for $t {
            #[inline]
            fn $method(&self, rhs: u32) -> Option<$t> {
                <$t>::$method(*self, rhs)
            }
        }
    }
}

checked_shift_impl!(CheckedShl, checked_shl, u8);
checked_shift_impl!(CheckedShl, checked_shl, u16);
checked_shift_impl!(CheckedShl, checked_shl, u32);
checked_shift_impl!(CheckedShl, checked_shl, u64);
checked_shift_impl!(CheckedShl, checked_shl, usize);

checked_shift_impl!(CheckedShl, checked_shl, i8);
checked_shift_impl!(CheckedShl, checked_shl, i16);
checked_shift_impl!(CheckedShl, checked_shl, i32);
checked_shift_impl!(CheckedShl, checked_shl, i64);
checked_shift_impl!(CheckedShl, checked_shl, isize);

/// Performs a right shift that returns `None` on overflow.
pub trait CheckedShr: Sized + Shr<u32, Output=Self> {
    /// Shifts a number to the left, checking for overflow. If overflow happens,
    /// `None` is returned.
    ///
    /// ```
    /// use num_traits::CheckedShr;
    ///
    /// let x: u16 = 0x8000;
    ///
    /// assert_eq!(CheckedShr::checked_shr(&x, 0),  Some(0x8000));
    /// assert_eq!(CheckedShr::checked_shr(&x, 1),  Some(0x4000));
    /// assert_eq!(CheckedShr::checked_shr(&x, 15), Some(0x0001));
    /// assert_eq!(CheckedShr::checked_shr(&x, 16), None);
    /// ```
    fn checked_shr(&self, rhs: u32) -> Option<Self>;
}

checked_shift_impl!(CheckedShr, checked_shr, u8);
checked_shift_impl!(CheckedShr, checked_shr, u16);
checked_shift_impl!(CheckedShr, checked_shr, u32);
checked_shift_impl!(CheckedShr, checked_shr, u64);
checked_shift_impl!(CheckedShr, checked_shr, usize);

checked_shift_impl!(CheckedShr, checked_shr, i8);
checked_shift_impl!(CheckedShr, checked_shr, i16);
checked_shift_impl!(CheckedShr, checked_shr, i32);
checked_shift_impl!(CheckedShr, checked_shr, i64);
checked_shift_impl!(CheckedShr, checked_shr, isize);