rust/library/core/tests/num/uint_macros.rs

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macro_rules! uint_module {
($T:ident, $T_i:ident) => {
#[cfg(test)]
mod tests {
use core::ops::{BitAnd, BitOr, BitXor, Not, Shl, Shr};
use core::$T_i::*;
use std::str::FromStr;
use crate::num;
#[test]
fn test_overflows() {
assert!(MAX > 0);
assert!(MIN <= 0);
assert!((MIN + MAX).wrapping_add(1) == 0);
}
#[test]
fn test_num() {
num::test_num(10 as $T, 2 as $T);
}
#[test]
fn test_bitwise_operators() {
assert!(0b1110 as $T == (0b1100 as $T).bitor(0b1010 as $T));
assert!(0b1000 as $T == (0b1100 as $T).bitand(0b1010 as $T));
assert!(0b0110 as $T == (0b1100 as $T).bitxor(0b1010 as $T));
assert!(0b1110 as $T == (0b0111 as $T).shl(1));
assert!(0b0111 as $T == (0b1110 as $T).shr(1));
assert!(MAX - (0b1011 as $T) == (0b1011 as $T).not());
}
const A: $T = 0b0101100;
const B: $T = 0b0100001;
const C: $T = 0b1111001;
const _0: $T = 0;
const _1: $T = !0;
#[test]
fn test_count_ones() {
assert!(A.count_ones() == 3);
assert!(B.count_ones() == 2);
assert!(C.count_ones() == 5);
}
#[test]
fn test_count_zeros() {
assert!(A.count_zeros() == $T::BITS - 3);
assert!(B.count_zeros() == $T::BITS - 2);
assert!(C.count_zeros() == $T::BITS - 5);
}
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#[test]
fn test_leading_trailing_ones() {
let a: $T = 0b0101_1111;
assert_eq!(a.trailing_ones(), 5);
assert_eq!((!a).leading_ones(), $T::BITS - 7);
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assert_eq!(a.reverse_bits().leading_ones(), 5);
assert_eq!(_1.leading_ones(), $T::BITS);
assert_eq!(_1.trailing_ones(), $T::BITS);
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assert_eq!((_1 << 1).trailing_ones(), 0);
assert_eq!((_1 >> 1).leading_ones(), 0);
assert_eq!((_1 << 1).leading_ones(), $T::BITS - 1);
assert_eq!((_1 >> 1).trailing_ones(), $T::BITS - 1);
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assert_eq!(_0.leading_ones(), 0);
assert_eq!(_0.trailing_ones(), 0);
let x: $T = 0b0010_1100;
assert_eq!(x.leading_ones(), 0);
assert_eq!(x.trailing_ones(), 0);
}
#[test]
fn test_rotate() {
assert_eq!(A.rotate_left(6).rotate_right(2).rotate_right(4), A);
assert_eq!(B.rotate_left(3).rotate_left(2).rotate_right(5), B);
assert_eq!(C.rotate_left(6).rotate_right(2).rotate_right(4), C);
// Rotating these should make no difference
//
// We test using 124 bits because to ensure that overlong bit shifts do
// not cause undefined behaviour. See #10183.
assert_eq!(_0.rotate_left(124), _0);
assert_eq!(_1.rotate_left(124), _1);
assert_eq!(_0.rotate_right(124), _0);
assert_eq!(_1.rotate_right(124), _1);
// Rotating by 0 should have no effect
assert_eq!(A.rotate_left(0), A);
assert_eq!(B.rotate_left(0), B);
assert_eq!(C.rotate_left(0), C);
// Rotating by a multiple of word size should also have no effect
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assert_eq!(A.rotate_left(128), A);
assert_eq!(B.rotate_left(128), B);
assert_eq!(C.rotate_left(128), C);
}
#[test]
fn test_swap_bytes() {
assert_eq!(A.swap_bytes().swap_bytes(), A);
assert_eq!(B.swap_bytes().swap_bytes(), B);
assert_eq!(C.swap_bytes().swap_bytes(), C);
// Swapping these should make no difference
assert_eq!(_0.swap_bytes(), _0);
assert_eq!(_1.swap_bytes(), _1);
}
#[test]
fn test_reverse_bits() {
assert_eq!(A.reverse_bits().reverse_bits(), A);
assert_eq!(B.reverse_bits().reverse_bits(), B);
assert_eq!(C.reverse_bits().reverse_bits(), C);
// Swapping these should make no difference
assert_eq!(_0.reverse_bits(), _0);
assert_eq!(_1.reverse_bits(), _1);
}
#[test]
fn test_le() {
assert_eq!($T::from_le(A.to_le()), A);
assert_eq!($T::from_le(B.to_le()), B);
assert_eq!($T::from_le(C.to_le()), C);
assert_eq!($T::from_le(_0), _0);
assert_eq!($T::from_le(_1), _1);
assert_eq!(_0.to_le(), _0);
assert_eq!(_1.to_le(), _1);
}
#[test]
fn test_be() {
assert_eq!($T::from_be(A.to_be()), A);
assert_eq!($T::from_be(B.to_be()), B);
assert_eq!($T::from_be(C.to_be()), C);
assert_eq!($T::from_be(_0), _0);
assert_eq!($T::from_be(_1), _1);
assert_eq!(_0.to_be(), _0);
assert_eq!(_1.to_be(), _1);
}
#[test]
fn test_unsigned_checked_div() {
assert!((10 as $T).checked_div(2) == Some(5));
assert!((5 as $T).checked_div(0) == None);
}
fn from_str<T: FromStr>(t: &str) -> Option<T> {
FromStr::from_str(t).ok()
}
#[test]
pub fn test_from_str() {
assert_eq!(from_str::<$T>("0"), Some(0 as $T));
assert_eq!(from_str::<$T>("3"), Some(3 as $T));
assert_eq!(from_str::<$T>("10"), Some(10 as $T));
assert_eq!(from_str::<u32>("123456789"), Some(123456789 as u32));
assert_eq!(from_str::<$T>("00100"), Some(100 as $T));
assert_eq!(from_str::<$T>(""), None);
assert_eq!(from_str::<$T>(" "), None);
assert_eq!(from_str::<$T>("x"), None);
}
#[test]
pub fn test_parse_bytes() {
assert_eq!($T::from_str_radix("123", 10), Ok(123 as $T));
assert_eq!($T::from_str_radix("1001", 2), Ok(9 as $T));
assert_eq!($T::from_str_radix("123", 8), Ok(83 as $T));
assert_eq!(u16::from_str_radix("123", 16), Ok(291 as u16));
assert_eq!(u16::from_str_radix("ffff", 16), Ok(65535 as u16));
assert_eq!($T::from_str_radix("z", 36), Ok(35 as $T));
assert_eq!($T::from_str_radix("Z", 10).ok(), None::<$T>);
assert_eq!($T::from_str_radix("_", 2).ok(), None::<$T>);
}
Rearrange the pipeline of `pow` to gain efficiency The check of the `exp` parameter seems useless if we execute the while-loop more than once. The original implementation of `pow` function using one more comparison if the `exp==0` and may break the pipeline of the cpu, which may generate a slower code. The performance gap between the old and the new implementation may be small, but IMO, at least the newer one looks more beautiful. --- bench prog: ``` extern crate test; ($a:expr)=>{let time=std::time::Instant::now();{$a;}print!("{:?} ",time.elapsed())}; ($a:expr,$b:literal)=>{let time=std::time::Instant::now();let mut a=0;for _ in 0..$b{a^=$a;}print!("{:?} {} ",time.elapsed(),a)} } pub fn pow_rust(x:i64, mut exp: u32) -> i64 { let mut base = x; let mut acc = 1; while exp > 1 { if (exp & 1) == 1 { acc = acc * base; } exp /= 2; base = base * base; } if exp == 1 { acc = acc * base; } acc } pub fn pow_new(x:i64, mut exp: u32) -> i64 { if exp==0{ 1 }else{ let mut base = x; let mut acc = 1; while exp > 1 { if (exp & 1) == 1 { acc = acc * base; } exp >>= 1; base = base * base; } acc * base } } fn main(){ let a=2i64; let b=1_u32; println!(); timing!(test::black_box(a).pow(test::black_box(b)),100000000); timing!(pow_new(test::black_box(a),test::black_box(b)),100000000); timing!(pow_rust(test::black_box(a),test::black_box(b)),100000000); println!(); timing!(test::black_box(a).pow(test::black_box(b)),100000000); timing!(pow_new(test::black_box(a),test::black_box(b)),100000000); timing!(pow_rust(test::black_box(a),test::black_box(b)),100000000); println!(); timing!(test::black_box(a).pow(test::black_box(b)),100000000); timing!(pow_new(test::black_box(a),test::black_box(b)),100000000); timing!(pow_rust(test::black_box(a),test::black_box(b)),100000000); println!(); timing!(test::black_box(a).pow(test::black_box(b)),100000000); timing!(pow_new(test::black_box(a),test::black_box(b)),100000000); timing!(pow_rust(test::black_box(a),test::black_box(b)),100000000); println!(); timing!(test::black_box(a).pow(test::black_box(b)),100000000); timing!(pow_new(test::black_box(a),test::black_box(b)),100000000); timing!(pow_rust(test::black_box(a),test::black_box(b)),100000000); println!(); timing!(test::black_box(a).pow(test::black_box(b)),100000000); timing!(pow_new(test::black_box(a),test::black_box(b)),100000000); timing!(pow_rust(test::black_box(a),test::black_box(b)),100000000); println!(); timing!(test::black_box(a).pow(test::black_box(b)),100000000); timing!(pow_new(test::black_box(a),test::black_box(b)),100000000); timing!(pow_rust(test::black_box(a),test::black_box(b)),100000000); println!(); timing!(test::black_box(a).pow(test::black_box(b)),100000000); timing!(pow_new(test::black_box(a),test::black_box(b)),100000000); timing!(pow_rust(test::black_box(a),test::black_box(b)),100000000); println!(); } ``` bench in my laptop: ``` neutron@Neutron:/me/rust$ rc commit.rs rustc commit.rs && ./commit 3.978419716s 0 4.079765171s 0 3.964630622s 0 3.997127013s 0 4.260304804s 0 3.997638211s 0 3.963195544s 0 4.11657718s 0 4.176054164s 0 3.830128579s 0 3.980396122s 0 3.937258567s 0 3.986055948s 0 4.127804162s 0 4.018943411s 0 4.185568857s 0 4.217512517s 0 3.98313603s 0 3.863018225s 0 4.030447988s 0 3.694878237s 0 4.206987927s 0 4.137608047s 0 4.115564664s 0 neutron@Neutron:/me/rust$ rc commit.rs -O rustc commit.rs -O && ./commit 162.111993ms 0 165.107125ms 0 166.26924ms 0 175.20479ms 0 205.062565ms 0 176.278791ms 0 174.408975ms 0 166.526899ms 0 201.857604ms 0 146.190062ms 0 168.592821ms 0 154.61411ms 0 199.678912ms 0 168.411598ms 0 162.129996ms 0 147.420765ms 0 209.759326ms 0 154.807907ms 0 165.507134ms 0 188.476239ms 0 157.351524ms 0 121.320123ms 0 126.401229ms 0 114.86428ms 0 ``` delete an unnecessary semicolon... Sorry for the typo. delete trailing whitespace Sorry, too.. Sorry for the missing... I checked all the implementations, and finally found that there is one function that does not check whether `exp == 0` add extra tests add extra tests. finished adding the extra tests to prevent further typo add pow(2) to negative exp add whitespace. add whitespace add whitespace delete extra line
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#[test]
fn test_pow() {
let mut r = 2 as $T;
assert_eq!(r.pow(2), 4 as $T);
assert_eq!(r.pow(0), 1 as $T);
assert_eq!(r.wrapping_pow(2), 4 as $T);
assert_eq!(r.wrapping_pow(0), 1 as $T);
assert_eq!(r.checked_pow(2), Some(4 as $T));
assert_eq!(r.checked_pow(0), Some(1 as $T));
assert_eq!(r.overflowing_pow(2), (4 as $T, false));
assert_eq!(r.overflowing_pow(0), (1 as $T, false));
assert_eq!(r.saturating_pow(2), 4 as $T);
assert_eq!(r.saturating_pow(0), 1 as $T);
r = MAX;
// use `^` to represent .pow() with no overflow.
// if itest::MAX == 2^j-1, then itest is a `j` bit int,
// so that `itest::MAX*itest::MAX == 2^(2*j)-2^(j+1)+1`,
// thussaturating_pow the overflowing result is exactly 1.
assert_eq!(r.wrapping_pow(2), 1 as $T);
assert_eq!(r.checked_pow(2), None);
assert_eq!(r.overflowing_pow(2), (1 as $T, true));
assert_eq!(r.saturating_pow(2), MAX);
}
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#[test]
fn test_div_floor() {
assert_eq!((8 as $T).div_floor(3), 2);
}
#[test]
fn test_div_ceil() {
assert_eq!((8 as $T).div_ceil(3), 3);
}
#[test]
fn test_next_multiple_of() {
assert_eq!((16 as $T).next_multiple_of(8), 16);
assert_eq!((23 as $T).next_multiple_of(8), 24);
assert_eq!(MAX.next_multiple_of(1), MAX);
}
#[test]
fn test_checked_next_multiple_of() {
assert_eq!((16 as $T).checked_next_multiple_of(8), Some(16));
assert_eq!((23 as $T).checked_next_multiple_of(8), Some(24));
assert_eq!((1 as $T).checked_next_multiple_of(0), None);
assert_eq!(MAX.checked_next_multiple_of(2), None);
}
}
};
}