1 //! Additional functionality for numerics.
3 //! This module provides some extra types that are useful when doing numerical
4 //! work. See the individual documentation for each piece for more information.
6 #![stable(feature = "rust1", since = "1.0.0")]
7 #![allow(missing_docs)]
9 #[stable(feature = "rust1", since = "1.0.0")]
10 pub use core::num::Wrapping;
11 #[stable(feature = "rust1", since = "1.0.0")]
12 pub use core::num::{FpCategory, ParseFloatError, ParseIntError, TryFromIntError};
14 #[stable(feature = "signed_nonzero", since = "1.34.0")]
15 pub use core::num::{NonZeroI128, NonZeroI16, NonZeroI32, NonZeroI64, NonZeroI8, NonZeroIsize};
16 #[stable(feature = "nonzero", since = "1.28.0")]
17 pub use core::num::{NonZeroU128, NonZeroU16, NonZeroU32, NonZeroU64, NonZeroU8, NonZeroUsize};
20 feature = "int_error_matching",
21 reason = "it can be useful to match errors when making error messages \
25 pub use core::num::IntErrorKind;
30 use crate::ops::{Add, Div, Mul, Rem, Sub};
32 /// Helper function for testing numeric operations
34 pub fn test_num<T>(ten: T, two: T)
45 assert_eq!(ten.add(two), ten + two);
46 assert_eq!(ten.sub(two), ten - two);
47 assert_eq!(ten.mul(two), ten * two);
48 assert_eq!(ten.div(two), ten / two);
49 assert_eq!(ten.rem(two), ten % two);
62 fn test_saturating_add_uint() {
63 use crate::usize::MAX;
64 assert_eq!(3_usize.saturating_add(5_usize), 8_usize);
65 assert_eq!(3_usize.saturating_add(MAX - 1), MAX);
66 assert_eq!(MAX.saturating_add(MAX), MAX);
67 assert_eq!((MAX - 2).saturating_add(1), MAX - 1);
71 fn test_saturating_sub_uint() {
72 use crate::usize::MAX;
73 assert_eq!(5_usize.saturating_sub(3_usize), 2_usize);
74 assert_eq!(3_usize.saturating_sub(5_usize), 0_usize);
75 assert_eq!(0_usize.saturating_sub(1_usize), 0_usize);
76 assert_eq!((MAX - 1).saturating_sub(MAX), 0);
80 fn test_saturating_add_int() {
81 use crate::isize::{MAX, MIN};
82 assert_eq!(3i32.saturating_add(5), 8);
83 assert_eq!(3isize.saturating_add(MAX - 1), MAX);
84 assert_eq!(MAX.saturating_add(MAX), MAX);
85 assert_eq!((MAX - 2).saturating_add(1), MAX - 1);
86 assert_eq!(3i32.saturating_add(-5), -2);
87 assert_eq!(MIN.saturating_add(-1), MIN);
88 assert_eq!((-2isize).saturating_add(-MAX), MIN);
92 fn test_saturating_sub_int() {
93 use crate::isize::{MAX, MIN};
94 assert_eq!(3i32.saturating_sub(5), -2);
95 assert_eq!(MIN.saturating_sub(1), MIN);
96 assert_eq!((-2isize).saturating_sub(MAX), MIN);
97 assert_eq!(3i32.saturating_sub(-5), 8);
98 assert_eq!(3isize.saturating_sub(-(MAX - 1)), MAX);
99 assert_eq!(MAX.saturating_sub(-MAX), MAX);
100 assert_eq!((MAX - 2).saturating_sub(-1), MAX - 1);
104 fn test_checked_add() {
105 let five_less = usize::MAX - 5;
106 assert_eq!(five_less.checked_add(0), Some(usize::MAX - 5));
107 assert_eq!(five_less.checked_add(1), Some(usize::MAX - 4));
108 assert_eq!(five_less.checked_add(2), Some(usize::MAX - 3));
109 assert_eq!(five_less.checked_add(3), Some(usize::MAX - 2));
110 assert_eq!(five_less.checked_add(4), Some(usize::MAX - 1));
111 assert_eq!(five_less.checked_add(5), Some(usize::MAX));
112 assert_eq!(five_less.checked_add(6), None);
113 assert_eq!(five_less.checked_add(7), None);
117 fn test_checked_sub() {
118 assert_eq!(5_usize.checked_sub(0), Some(5));
119 assert_eq!(5_usize.checked_sub(1), Some(4));
120 assert_eq!(5_usize.checked_sub(2), Some(3));
121 assert_eq!(5_usize.checked_sub(3), Some(2));
122 assert_eq!(5_usize.checked_sub(4), Some(1));
123 assert_eq!(5_usize.checked_sub(5), Some(0));
124 assert_eq!(5_usize.checked_sub(6), None);
125 assert_eq!(5_usize.checked_sub(7), None);
129 fn test_checked_mul() {
130 let third = usize::MAX / 3;
131 assert_eq!(third.checked_mul(0), Some(0));
132 assert_eq!(third.checked_mul(1), Some(third));
133 assert_eq!(third.checked_mul(2), Some(third * 2));
134 assert_eq!(third.checked_mul(3), Some(third * 3));
135 assert_eq!(third.checked_mul(4), None);
138 macro_rules! test_is_power_of_two {
139 ($test_name:ident, $T:ident) => {
142 assert_eq!((0 as $T).is_power_of_two(), false);
143 assert_eq!((1 as $T).is_power_of_two(), true);
144 assert_eq!((2 as $T).is_power_of_two(), true);
145 assert_eq!((3 as $T).is_power_of_two(), false);
146 assert_eq!((4 as $T).is_power_of_two(), true);
147 assert_eq!((5 as $T).is_power_of_two(), false);
148 assert_eq!(($T::MAX / 2 + 1).is_power_of_two(), true);
153 test_is_power_of_two! { test_is_power_of_two_u8, u8 }
154 test_is_power_of_two! { test_is_power_of_two_u16, u16 }
155 test_is_power_of_two! { test_is_power_of_two_u32, u32 }
156 test_is_power_of_two! { test_is_power_of_two_u64, u64 }
157 test_is_power_of_two! { test_is_power_of_two_uint, usize }
159 macro_rules! test_next_power_of_two {
160 ($test_name:ident, $T:ident) => {
163 assert_eq!((0 as $T).next_power_of_two(), 1);
164 let mut next_power = 1;
165 for i in 1 as $T..40 {
166 assert_eq!(i.next_power_of_two(), next_power);
175 test_next_power_of_two! { test_next_power_of_two_u8, u8 }
176 test_next_power_of_two! { test_next_power_of_two_u16, u16 }
177 test_next_power_of_two! { test_next_power_of_two_u32, u32 }
178 test_next_power_of_two! { test_next_power_of_two_u64, u64 }
179 test_next_power_of_two! { test_next_power_of_two_uint, usize }
181 macro_rules! test_checked_next_power_of_two {
182 ($test_name:ident, $T:ident) => {
185 assert_eq!((0 as $T).checked_next_power_of_two(), Some(1));
186 let smax = $T::MAX >> 1;
187 assert_eq!(smax.checked_next_power_of_two(), Some(smax + 1));
188 assert_eq!((smax + 1).checked_next_power_of_two(), Some(smax + 1));
189 assert_eq!((smax + 2).checked_next_power_of_two(), None);
190 assert_eq!(($T::MAX - 1).checked_next_power_of_two(), None);
191 assert_eq!($T::MAX.checked_next_power_of_two(), None);
192 let mut next_power = 1;
193 for i in 1 as $T..40 {
194 assert_eq!(i.checked_next_power_of_two(), Some(next_power));
203 test_checked_next_power_of_two! { test_checked_next_power_of_two_u8, u8 }
204 test_checked_next_power_of_two! { test_checked_next_power_of_two_u16, u16 }
205 test_checked_next_power_of_two! { test_checked_next_power_of_two_u32, u32 }
206 test_checked_next_power_of_two! { test_checked_next_power_of_two_u64, u64 }
207 test_checked_next_power_of_two! { test_checked_next_power_of_two_uint, usize }
211 fn naive_pow<T: Mul<Output = T> + Copy>(one: T, base: T, exp: usize) -> T {
212 (0..exp).fold(one, |acc, _| acc * base)
214 macro_rules! assert_pow {
215 (($num:expr, $exp:expr) => $expected:expr) => {{
216 let result = $num.pow($exp);
217 assert_eq!(result, $expected);
218 assert_eq!(result, naive_pow(1, $num, $exp));
221 assert_pow!((3u32, 0 ) => 1);
222 assert_pow!((5u32, 1 ) => 5);
223 assert_pow!((-4i32, 2 ) => 16);
224 assert_pow!((8u32, 3 ) => 512);
225 assert_pow!((2u64, 50) => 1125899906842624);
229 fn test_uint_to_str_overflow() {
230 let mut u8_val: u8 = 255;
231 assert_eq!(u8_val.to_string(), "255");
233 u8_val = u8_val.wrapping_add(1);
234 assert_eq!(u8_val.to_string(), "0");
236 let mut u16_val: u16 = 65_535;
237 assert_eq!(u16_val.to_string(), "65535");
239 u16_val = u16_val.wrapping_add(1);
240 assert_eq!(u16_val.to_string(), "0");
242 let mut u32_val: u32 = 4_294_967_295;
243 assert_eq!(u32_val.to_string(), "4294967295");
245 u32_val = u32_val.wrapping_add(1);
246 assert_eq!(u32_val.to_string(), "0");
248 let mut u64_val: u64 = 18_446_744_073_709_551_615;
249 assert_eq!(u64_val.to_string(), "18446744073709551615");
251 u64_val = u64_val.wrapping_add(1);
252 assert_eq!(u64_val.to_string(), "0");
255 fn from_str<T: crate::str::FromStr>(t: &str) -> Option<T> {
256 crate::str::FromStr::from_str(t).ok()
260 fn test_uint_from_str_overflow() {
261 let mut u8_val: u8 = 255;
262 assert_eq!(from_str::<u8>("255"), Some(u8_val));
263 assert_eq!(from_str::<u8>("256"), None);
265 u8_val = u8_val.wrapping_add(1);
266 assert_eq!(from_str::<u8>("0"), Some(u8_val));
267 assert_eq!(from_str::<u8>("-1"), None);
269 let mut u16_val: u16 = 65_535;
270 assert_eq!(from_str::<u16>("65535"), Some(u16_val));
271 assert_eq!(from_str::<u16>("65536"), None);
273 u16_val = u16_val.wrapping_add(1);
274 assert_eq!(from_str::<u16>("0"), Some(u16_val));
275 assert_eq!(from_str::<u16>("-1"), None);
277 let mut u32_val: u32 = 4_294_967_295;
278 assert_eq!(from_str::<u32>("4294967295"), Some(u32_val));
279 assert_eq!(from_str::<u32>("4294967296"), None);
281 u32_val = u32_val.wrapping_add(1);
282 assert_eq!(from_str::<u32>("0"), Some(u32_val));
283 assert_eq!(from_str::<u32>("-1"), None);
285 let mut u64_val: u64 = 18_446_744_073_709_551_615;
286 assert_eq!(from_str::<u64>("18446744073709551615"), Some(u64_val));
287 assert_eq!(from_str::<u64>("18446744073709551616"), None);
289 u64_val = u64_val.wrapping_add(1);
290 assert_eq!(from_str::<u64>("0"), Some(u64_val));
291 assert_eq!(from_str::<u64>("-1"), None);
300 fn bench_pow_function(b: &mut Bencher) {
301 let v = (0..1024).collect::<Vec<u32>>();
303 v.iter().fold(0u32, |old, new| old.pow(*new as u32));