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
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
use core::ops::{Add, Sub, Mul, Div, Rem, 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);
#[cfg(has_i128)]
checked_impl!(CheckedAdd, checked_add, u128);

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);
#[cfg(has_i128)]
checked_impl!(CheckedAdd, checked_add, i128);

/// 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);
#[cfg(has_i128)]
checked_impl!(CheckedSub, checked_sub, u128);

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);
#[cfg(has_i128)]
checked_impl!(CheckedSub, checked_sub, i128);

/// 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);
#[cfg(has_i128)]
checked_impl!(CheckedMul, checked_mul, u128);

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);
#[cfg(has_i128)]
checked_impl!(CheckedMul, checked_mul, i128);

/// 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);
#[cfg(has_i128)]
checked_impl!(CheckedDiv, checked_div, u128);

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);
#[cfg(has_i128)]
checked_impl!(CheckedDiv, checked_div, i128);

/// Performs an integral remainder that returns `None` instead of panicking on division by zero and
/// instead of wrapping around on underflow and overflow.
pub trait CheckedRem: Sized + Rem<Self, Output = Self> {
    /// Finds the remainder of dividing two numbers, checking for underflow, overflow and division
    /// by zero. If any of that happens, `None` is returned.
    ///
    /// # Examples
    ///
    /// ```
    /// use num_traits::CheckedRem;
    /// use std::i32::MIN;
    ///
    /// assert_eq!(CheckedRem::checked_rem(&10, &7), Some(3));
    /// assert_eq!(CheckedRem::checked_rem(&10, &-7), Some(3));
    /// assert_eq!(CheckedRem::checked_rem(&-10, &7), Some(-3));
    /// assert_eq!(CheckedRem::checked_rem(&-10, &-7), Some(-3));
    ///
    /// assert_eq!(CheckedRem::checked_rem(&10, &0), None);
    ///
    /// assert_eq!(CheckedRem::checked_rem(&MIN, &1), Some(0));
    /// assert_eq!(CheckedRem::checked_rem(&MIN, &-1), None);
    /// ```
    fn checked_rem(&self, v: &Self) -> Option<Self>;
}

checked_impl!(CheckedRem, checked_rem, u8);
checked_impl!(CheckedRem, checked_rem, u16);
checked_impl!(CheckedRem, checked_rem, u32);
checked_impl!(CheckedRem, checked_rem, u64);
checked_impl!(CheckedRem, checked_rem, usize);
#[cfg(has_i128)]
checked_impl!(CheckedRem, checked_rem, u128);

checked_impl!(CheckedRem, checked_rem, i8);
checked_impl!(CheckedRem, checked_rem, i16);
checked_impl!(CheckedRem, checked_rem, i32);
checked_impl!(CheckedRem, checked_rem, i64);
checked_impl!(CheckedRem, checked_rem, isize);
#[cfg(has_i128)]
checked_impl!(CheckedRem, checked_rem, i128);

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

/// Performs negation that returns `None` if the result can't be represented.
pub trait CheckedNeg: Sized {
    /// Negates a number, returning `None` for results that can't be represented, like signed `MIN`
    /// values that can't be positive, or non-zero unsigned values that can't be negative.
    ///
    /// # Examples
    ///
    /// ```
    /// use num_traits::CheckedNeg;
    /// use std::i32::MIN;
    ///
    /// assert_eq!(CheckedNeg::checked_neg(&1_i32), Some(-1));
    /// assert_eq!(CheckedNeg::checked_neg(&-1_i32), Some(1));
    /// assert_eq!(CheckedNeg::checked_neg(&MIN), None);
    ///
    /// assert_eq!(CheckedNeg::checked_neg(&0_u32), Some(0));
    /// assert_eq!(CheckedNeg::checked_neg(&1_u32), None);
    /// ```
    fn checked_neg(&self) -> Option<Self>;
}

checked_impl_unary!(CheckedNeg, checked_neg, u8);
checked_impl_unary!(CheckedNeg, checked_neg, u16);
checked_impl_unary!(CheckedNeg, checked_neg, u32);
checked_impl_unary!(CheckedNeg, checked_neg, u64);
checked_impl_unary!(CheckedNeg, checked_neg, usize);
#[cfg(has_i128)]
checked_impl_unary!(CheckedNeg, checked_neg, u128);

checked_impl_unary!(CheckedNeg, checked_neg, i8);
checked_impl_unary!(CheckedNeg, checked_neg, i16);
checked_impl_unary!(CheckedNeg, checked_neg, i32);
checked_impl_unary!(CheckedNeg, checked_neg, i64);
checked_impl_unary!(CheckedNeg, checked_neg, isize);
#[cfg(has_i128)]
checked_impl_unary!(CheckedNeg, checked_neg, i128);

/// 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);
#[cfg(has_i128)]
checked_shift_impl!(CheckedShl, checked_shl, u128);

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);
#[cfg(has_i128)]
checked_shift_impl!(CheckedShl, checked_shl, i128);

/// 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);
#[cfg(has_i128)]
checked_shift_impl!(CheckedShr, checked_shr, u128);

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);
#[cfg(has_i128)]
checked_shift_impl!(CheckedShr, checked_shr, i128);