1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! Additional functionality for numerics.
13 //! This module provides some extra types that are useful when doing numerical
14 //! work. See the individual documentation for each piece for more information.
16 #![stable(feature = "rust1", since = "1.0.0")]
17 #![allow(missing_docs)]
19 #[stable(feature = "rust1", since = "1.0.0")]
20 pub use core::num::{FpCategory, ParseIntError, ParseFloatError, TryFromIntError};
21 #[stable(feature = "rust1", since = "1.0.0")]
22 pub use core::num::Wrapping;
25 #[cfg(test)] use ops::{Add, Sub, Mul, Div, Rem};
27 /// Helper function for testing numeric operations
29 pub fn test_num<T>(ten: T, two: T) where
31 + Add<Output=T> + Sub<Output=T>
32 + Mul<Output=T> + Div<Output=T>
33 + Rem<Output=T> + fmt::Debug
36 assert_eq!(ten.add(two), ten + two);
37 assert_eq!(ten.sub(two), ten - two);
38 assert_eq!(ten.mul(two), ten * two);
39 assert_eq!(ten.div(two), ten / two);
40 assert_eq!(ten.rem(two), ten % two);
53 fn test_saturating_add_uint() {
55 assert_eq!(3_usize.saturating_add(5_usize), 8_usize);
56 assert_eq!(3_usize.saturating_add(MAX-1), MAX);
57 assert_eq!(MAX.saturating_add(MAX), MAX);
58 assert_eq!((MAX-2).saturating_add(1), MAX-1);
62 fn test_saturating_sub_uint() {
64 assert_eq!(5_usize.saturating_sub(3_usize), 2_usize);
65 assert_eq!(3_usize.saturating_sub(5_usize), 0_usize);
66 assert_eq!(0_usize.saturating_sub(1_usize), 0_usize);
67 assert_eq!((MAX-1).saturating_sub(MAX), 0);
71 fn test_saturating_add_int() {
73 assert_eq!(3i32.saturating_add(5), 8);
74 assert_eq!(3isize.saturating_add(MAX-1), MAX);
75 assert_eq!(MAX.saturating_add(MAX), MAX);
76 assert_eq!((MAX-2).saturating_add(1), MAX-1);
77 assert_eq!(3i32.saturating_add(-5), -2);
78 assert_eq!(MIN.saturating_add(-1), MIN);
79 assert_eq!((-2isize).saturating_add(-MAX), MIN);
83 fn test_saturating_sub_int() {
85 assert_eq!(3i32.saturating_sub(5), -2);
86 assert_eq!(MIN.saturating_sub(1), MIN);
87 assert_eq!((-2isize).saturating_sub(MAX), MIN);
88 assert_eq!(3i32.saturating_sub(-5), 8);
89 assert_eq!(3isize.saturating_sub(-(MAX-1)), MAX);
90 assert_eq!(MAX.saturating_sub(-MAX), MAX);
91 assert_eq!((MAX-2).saturating_sub(-1), MAX-1);
95 fn test_checked_add() {
96 let five_less = usize::MAX - 5;
97 assert_eq!(five_less.checked_add(0), Some(usize::MAX - 5));
98 assert_eq!(five_less.checked_add(1), Some(usize::MAX - 4));
99 assert_eq!(five_less.checked_add(2), Some(usize::MAX - 3));
100 assert_eq!(five_less.checked_add(3), Some(usize::MAX - 2));
101 assert_eq!(five_less.checked_add(4), Some(usize::MAX - 1));
102 assert_eq!(five_less.checked_add(5), Some(usize::MAX));
103 assert_eq!(five_less.checked_add(6), None);
104 assert_eq!(five_less.checked_add(7), None);
108 fn test_checked_sub() {
109 assert_eq!(5_usize.checked_sub(0), Some(5));
110 assert_eq!(5_usize.checked_sub(1), Some(4));
111 assert_eq!(5_usize.checked_sub(2), Some(3));
112 assert_eq!(5_usize.checked_sub(3), Some(2));
113 assert_eq!(5_usize.checked_sub(4), Some(1));
114 assert_eq!(5_usize.checked_sub(5), Some(0));
115 assert_eq!(5_usize.checked_sub(6), None);
116 assert_eq!(5_usize.checked_sub(7), None);
120 fn test_checked_mul() {
121 let third = usize::MAX / 3;
122 assert_eq!(third.checked_mul(0), Some(0));
123 assert_eq!(third.checked_mul(1), Some(third));
124 assert_eq!(third.checked_mul(2), Some(third * 2));
125 assert_eq!(third.checked_mul(3), Some(third * 3));
126 assert_eq!(third.checked_mul(4), None);
129 macro_rules! test_is_power_of_two {
130 ($test_name:ident, $T:ident) => (
133 assert_eq!((0 as $T).is_power_of_two(), false);
134 assert_eq!((1 as $T).is_power_of_two(), true);
135 assert_eq!((2 as $T).is_power_of_two(), true);
136 assert_eq!((3 as $T).is_power_of_two(), false);
137 assert_eq!((4 as $T).is_power_of_two(), true);
138 assert_eq!((5 as $T).is_power_of_two(), false);
139 assert_eq!(($T::MAX / 2 + 1).is_power_of_two(), true);
144 test_is_power_of_two!{ test_is_power_of_two_u8, u8 }
145 test_is_power_of_two!{ test_is_power_of_two_u16, u16 }
146 test_is_power_of_two!{ test_is_power_of_two_u32, u32 }
147 test_is_power_of_two!{ test_is_power_of_two_u64, u64 }
148 test_is_power_of_two!{ test_is_power_of_two_uint, usize }
150 macro_rules! test_next_power_of_two {
151 ($test_name:ident, $T:ident) => (
154 assert_eq!((0 as $T).next_power_of_two(), 1);
155 let mut next_power = 1;
156 for i in 1 as $T..40 {
157 assert_eq!(i.next_power_of_two(), next_power);
158 if i == next_power { next_power *= 2 }
164 test_next_power_of_two! { test_next_power_of_two_u8, u8 }
165 test_next_power_of_two! { test_next_power_of_two_u16, u16 }
166 test_next_power_of_two! { test_next_power_of_two_u32, u32 }
167 test_next_power_of_two! { test_next_power_of_two_u64, u64 }
168 test_next_power_of_two! { test_next_power_of_two_uint, usize }
170 macro_rules! test_checked_next_power_of_two {
171 ($test_name:ident, $T:ident) => (
172 #[cfg_attr(target_os = "emscripten", ignore)] // FIXME(#39119)
175 assert_eq!((0 as $T).checked_next_power_of_two(), Some(1));
176 assert!(($T::MAX / 2).checked_next_power_of_two().is_some());
177 assert_eq!(($T::MAX - 1).checked_next_power_of_two(), None);
178 assert_eq!($T::MAX.checked_next_power_of_two(), None);
179 let mut next_power = 1;
180 for i in 1 as $T..40 {
181 assert_eq!(i.checked_next_power_of_two(), Some(next_power));
182 if i == next_power { next_power *= 2 }
188 test_checked_next_power_of_two! { test_checked_next_power_of_two_u8, u8 }
189 test_checked_next_power_of_two! { test_checked_next_power_of_two_u16, u16 }
190 test_checked_next_power_of_two! { test_checked_next_power_of_two_u32, u32 }
191 test_checked_next_power_of_two! { test_checked_next_power_of_two_u64, u64 }
192 test_checked_next_power_of_two! { test_checked_next_power_of_two_uint, usize }
196 fn naive_pow<T: Mul<Output=T> + Copy>(one: T, base: T, exp: usize) -> T {
197 (0..exp).fold(one, |acc, _| acc * base)
199 macro_rules! assert_pow {
200 (($num:expr, $exp:expr) => $expected:expr) => {{
201 let result = $num.pow($exp);
202 assert_eq!(result, $expected);
203 assert_eq!(result, naive_pow(1, $num, $exp));
206 assert_pow!((3u32, 0 ) => 1);
207 assert_pow!((5u32, 1 ) => 5);
208 assert_pow!((-4i32, 2 ) => 16);
209 assert_pow!((8u32, 3 ) => 512);
210 assert_pow!((2u64, 50) => 1125899906842624);
214 fn test_uint_to_str_overflow() {
215 let mut u8_val: u8 = 255;
216 assert_eq!(u8_val.to_string(), "255");
218 u8_val = u8_val.wrapping_add(1);
219 assert_eq!(u8_val.to_string(), "0");
221 let mut u16_val: u16 = 65_535;
222 assert_eq!(u16_val.to_string(), "65535");
224 u16_val = u16_val.wrapping_add(1);
225 assert_eq!(u16_val.to_string(), "0");
227 let mut u32_val: u32 = 4_294_967_295;
228 assert_eq!(u32_val.to_string(), "4294967295");
230 u32_val = u32_val.wrapping_add(1);
231 assert_eq!(u32_val.to_string(), "0");
233 let mut u64_val: u64 = 18_446_744_073_709_551_615;
234 assert_eq!(u64_val.to_string(), "18446744073709551615");
236 u64_val = u64_val.wrapping_add(1);
237 assert_eq!(u64_val.to_string(), "0");
240 fn from_str<T: ::str::FromStr>(t: &str) -> Option<T> {
241 ::str::FromStr::from_str(t).ok()
245 fn test_uint_from_str_overflow() {
246 let mut u8_val: u8 = 255;
247 assert_eq!(from_str::<u8>("255"), Some(u8_val));
248 assert_eq!(from_str::<u8>("256"), None);
250 u8_val = u8_val.wrapping_add(1);
251 assert_eq!(from_str::<u8>("0"), Some(u8_val));
252 assert_eq!(from_str::<u8>("-1"), None);
254 let mut u16_val: u16 = 65_535;
255 assert_eq!(from_str::<u16>("65535"), Some(u16_val));
256 assert_eq!(from_str::<u16>("65536"), None);
258 u16_val = u16_val.wrapping_add(1);
259 assert_eq!(from_str::<u16>("0"), Some(u16_val));
260 assert_eq!(from_str::<u16>("-1"), None);
262 let mut u32_val: u32 = 4_294_967_295;
263 assert_eq!(from_str::<u32>("4294967295"), Some(u32_val));
264 assert_eq!(from_str::<u32>("4294967296"), None);
266 u32_val = u32_val.wrapping_add(1);
267 assert_eq!(from_str::<u32>("0"), Some(u32_val));
268 assert_eq!(from_str::<u32>("-1"), None);
270 let mut u64_val: u64 = 18_446_744_073_709_551_615;
271 assert_eq!(from_str::<u64>("18446744073709551615"), Some(u64_val));
272 assert_eq!(from_str::<u64>("18446744073709551616"), None);
274 u64_val = u64_val.wrapping_add(1);
275 assert_eq!(from_str::<u64>("0"), Some(u64_val));
276 assert_eq!(from_str::<u64>("-1"), None);
284 use self::test::Bencher;
287 fn bench_pow_function(b: &mut Bencher) {
288 let v = (0..1024).collect::<Vec<u32>>();
289 b.iter(|| {v.iter().fold(0u32, |old, new| old.pow(*new as u32));});