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 //! Numeric traits and functions for generic mathematics
13 //! These are implemented for the primitive numeric types in `std::{u8, u16,
14 //! u32, u64, usize, i8, i16, i32, i64, isize, f32, f64}`.
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::{Zero, One};
21 #[stable(feature = "rust1", since = "1.0.0")]
22 pub use core::num::{FpCategory, ParseIntError, ParseFloatError};
23 #[stable(feature = "rust1", since = "1.0.0")]
24 pub use core::num::{wrapping, Wrapping};
26 #[cfg(test)] use cmp::PartialEq;
28 #[cfg(test)] use marker::Copy;
29 #[cfg(test)] use ops::{Add, Sub, Mul, Div, Rem};
31 /// Helper function for testing numeric operations
33 pub fn test_num<T>(ten: T, two: T) where
35 + Add<Output=T> + Sub<Output=T>
36 + Mul<Output=T> + Div<Output=T>
37 + Rem<Output=T> + fmt::Debug
40 assert_eq!(ten.add(two), ten + two);
41 assert_eq!(ten.sub(two), ten - two);
42 assert_eq!(ten.mul(two), ten * two);
43 assert_eq!(ten.div(two), ten / two);
44 assert_eq!(ten.rem(two), ten % two);
64 fn test_saturating_add_uint() {
66 assert_eq!(3_usize.saturating_add(5_usize), 8_usize);
67 assert_eq!(3_usize.saturating_add(MAX-1), MAX);
68 assert_eq!(MAX.saturating_add(MAX), MAX);
69 assert_eq!((MAX-2).saturating_add(1), MAX-1);
73 fn test_saturating_sub_uint() {
75 assert_eq!(5_usize.saturating_sub(3_usize), 2_usize);
76 assert_eq!(3_usize.saturating_sub(5_usize), 0_usize);
77 assert_eq!(0_usize.saturating_sub(1_usize), 0_usize);
78 assert_eq!((MAX-1).saturating_sub(MAX), 0);
82 fn test_saturating_add_int() {
84 assert_eq!(3i32.saturating_add(5), 8);
85 assert_eq!(3isize.saturating_add(MAX-1), MAX);
86 assert_eq!(MAX.saturating_add(MAX), MAX);
87 assert_eq!((MAX-2).saturating_add(1), MAX-1);
88 assert_eq!(3i32.saturating_add(-5), -2);
89 assert_eq!(MIN.saturating_add(-1), MIN);
90 assert_eq!((-2isize).saturating_add(-MAX), MIN);
94 fn test_saturating_sub_int() {
96 assert_eq!(3i32.saturating_sub(5), -2);
97 assert_eq!(MIN.saturating_sub(1), MIN);
98 assert_eq!((-2isize).saturating_sub(MAX), MIN);
99 assert_eq!(3i32.saturating_sub(-5), 8);
100 assert_eq!(3isize.saturating_sub(-(MAX-1)), MAX);
101 assert_eq!(MAX.saturating_sub(-MAX), MAX);
102 assert_eq!((MAX-2).saturating_sub(-1), MAX-1);
106 fn test_checked_add() {
107 let five_less = usize::MAX - 5;
108 assert_eq!(five_less.checked_add(0), Some(usize::MAX - 5));
109 assert_eq!(five_less.checked_add(1), Some(usize::MAX - 4));
110 assert_eq!(five_less.checked_add(2), Some(usize::MAX - 3));
111 assert_eq!(five_less.checked_add(3), Some(usize::MAX - 2));
112 assert_eq!(five_less.checked_add(4), Some(usize::MAX - 1));
113 assert_eq!(five_less.checked_add(5), Some(usize::MAX));
114 assert_eq!(five_less.checked_add(6), None);
115 assert_eq!(five_less.checked_add(7), None);
119 fn test_checked_sub() {
120 assert_eq!(5_usize.checked_sub(0), Some(5));
121 assert_eq!(5_usize.checked_sub(1), Some(4));
122 assert_eq!(5_usize.checked_sub(2), Some(3));
123 assert_eq!(5_usize.checked_sub(3), Some(2));
124 assert_eq!(5_usize.checked_sub(4), Some(1));
125 assert_eq!(5_usize.checked_sub(5), Some(0));
126 assert_eq!(5_usize.checked_sub(6), None);
127 assert_eq!(5_usize.checked_sub(7), None);
131 fn test_checked_mul() {
132 let third = usize::MAX / 3;
133 assert_eq!(third.checked_mul(0), Some(0));
134 assert_eq!(third.checked_mul(1), Some(third));
135 assert_eq!(third.checked_mul(2), Some(third * 2));
136 assert_eq!(third.checked_mul(3), Some(third * 3));
137 assert_eq!(third.checked_mul(4), None);
140 macro_rules! test_is_power_of_two {
141 ($test_name:ident, $T:ident) => (
144 assert_eq!((0 as $T).is_power_of_two(), false);
145 assert_eq!((1 as $T).is_power_of_two(), true);
146 assert_eq!((2 as $T).is_power_of_two(), true);
147 assert_eq!((3 as $T).is_power_of_two(), false);
148 assert_eq!((4 as $T).is_power_of_two(), true);
149 assert_eq!((5 as $T).is_power_of_two(), false);
150 assert_eq!(($T::MAX / 2 + 1).is_power_of_two(), true);
155 test_is_power_of_two!{ test_is_power_of_two_u8, u8 }
156 test_is_power_of_two!{ test_is_power_of_two_u16, u16 }
157 test_is_power_of_two!{ test_is_power_of_two_u32, u32 }
158 test_is_power_of_two!{ test_is_power_of_two_u64, u64 }
159 test_is_power_of_two!{ test_is_power_of_two_uint, usize }
161 macro_rules! test_next_power_of_two {
162 ($test_name:ident, $T:ident) => (
165 assert_eq!((0 as $T).next_power_of_two(), 1);
166 let mut next_power = 1;
167 for i in 1 as $T..40 {
168 assert_eq!(i.next_power_of_two(), next_power);
169 if i == next_power { next_power *= 2 }
175 test_next_power_of_two! { test_next_power_of_two_u8, u8 }
176 test_next_power_of_two! { test_next_power_of_two_u16, u16 }
177 test_next_power_of_two! { test_next_power_of_two_u32, u32 }
178 test_next_power_of_two! { test_next_power_of_two_u64, u64 }
179 test_next_power_of_two! { test_next_power_of_two_uint, usize }
181 macro_rules! test_checked_next_power_of_two {
182 ($test_name:ident, $T:ident) => (
185 assert_eq!((0 as $T).checked_next_power_of_two(), Some(1));
186 assert!(($T::MAX / 2).checked_next_power_of_two().is_some());
187 assert_eq!(($T::MAX - 1).checked_next_power_of_two(), None);
188 assert_eq!($T::MAX.checked_next_power_of_two(), None);
189 let mut next_power = 1;
190 for i in 1 as $T..40 {
191 assert_eq!(i.checked_next_power_of_two(), Some(next_power));
192 if i == next_power { next_power *= 2 }
198 test_checked_next_power_of_two! { test_checked_next_power_of_two_u8, u8 }
199 test_checked_next_power_of_two! { test_checked_next_power_of_two_u16, u16 }
200 test_checked_next_power_of_two! { test_checked_next_power_of_two_u32, u32 }
201 test_checked_next_power_of_two! { test_checked_next_power_of_two_u64, u64 }
202 test_checked_next_power_of_two! { test_checked_next_power_of_two_uint, usize }
206 fn naive_pow<T: Mul<Output=T> + One + Copy>(base: T, exp: usize) -> T {
207 let one: T = T::one();
208 (0..exp).fold(one, |acc, _| acc * base)
210 macro_rules! assert_pow {
211 (($num:expr, $exp:expr) => $expected:expr) => {{
212 let result = $num.pow($exp);
213 assert_eq!(result, $expected);
214 assert_eq!(result, naive_pow($num, $exp));
217 assert_pow!((3u32, 0 ) => 1);
218 assert_pow!((5u32, 1 ) => 5);
219 assert_pow!((-4i32, 2 ) => 16);
220 assert_pow!((8u32, 3 ) => 512);
221 assert_pow!((2u64, 50) => 1125899906842624);
225 fn test_uint_to_str_overflow() {
226 let mut u8_val: u8 = 255;
227 assert_eq!(u8_val.to_string(), "255");
229 u8_val = u8_val.wrapping_add(1);
230 assert_eq!(u8_val.to_string(), "0");
232 let mut u16_val: u16 = 65_535;
233 assert_eq!(u16_val.to_string(), "65535");
235 u16_val = u16_val.wrapping_add(1);
236 assert_eq!(u16_val.to_string(), "0");
238 let mut u32_val: u32 = 4_294_967_295;
239 assert_eq!(u32_val.to_string(), "4294967295");
241 u32_val = u32_val.wrapping_add(1);
242 assert_eq!(u32_val.to_string(), "0");
244 let mut u64_val: u64 = 18_446_744_073_709_551_615;
245 assert_eq!(u64_val.to_string(), "18446744073709551615");
247 u64_val = u64_val.wrapping_add(1);
248 assert_eq!(u64_val.to_string(), "0");
251 fn from_str<T: ::str::FromStr>(t: &str) -> Option<T> {
252 ::str::FromStr::from_str(t).ok()
256 fn test_uint_from_str_overflow() {
257 let mut u8_val: u8 = 255;
258 assert_eq!(from_str::<u8>("255"), Some(u8_val));
259 assert_eq!(from_str::<u8>("256"), None);
261 u8_val = u8_val.wrapping_add(1);
262 assert_eq!(from_str::<u8>("0"), Some(u8_val));
263 assert_eq!(from_str::<u8>("-1"), None);
265 let mut u16_val: u16 = 65_535;
266 assert_eq!(from_str::<u16>("65535"), Some(u16_val));
267 assert_eq!(from_str::<u16>("65536"), None);
269 u16_val = u16_val.wrapping_add(1);
270 assert_eq!(from_str::<u16>("0"), Some(u16_val));
271 assert_eq!(from_str::<u16>("-1"), None);
273 let mut u32_val: u32 = 4_294_967_295;
274 assert_eq!(from_str::<u32>("4294967295"), Some(u32_val));
275 assert_eq!(from_str::<u32>("4294967296"), None);
277 u32_val = u32_val.wrapping_add(1);
278 assert_eq!(from_str::<u32>("0"), Some(u32_val));
279 assert_eq!(from_str::<u32>("-1"), None);
281 let mut u64_val: u64 = 18_446_744_073_709_551_615;
282 assert_eq!(from_str::<u64>("18446744073709551615"), Some(u64_val));
283 assert_eq!(from_str::<u64>("18446744073709551616"), None);
285 u64_val = u64_val.wrapping_add(1);
286 assert_eq!(from_str::<u64>("0"), Some(u64_val));
287 assert_eq!(from_str::<u64>("-1"), None);
295 use self::test::Bencher;
299 fn bench_pow_function(b: &mut Bencher) {
300 let v = (0..1024).collect::<Vec<u32>>();
301 b.iter(|| {v.iter().fold(0u32, |old, new| old.pow(*new as u32));});