mirror of
https://github.com/zerotier/ZeroTierOne.git
synced 2025-02-04 02:00:46 +00:00
90 lines
2.5 KiB
Rust
90 lines
2.5 KiB
Rust
// Translated from C to Rust. The original C code can be found at
|
|
// https://github.com/ulfjack/ryu and carries the following license:
|
|
//
|
|
// Copyright 2018 Ulf Adams
|
|
//
|
|
// The contents of this file may be used under the terms of the Apache License,
|
|
// Version 2.0.
|
|
//
|
|
// (See accompanying file LICENSE-Apache or copy at
|
|
// http://www.apache.org/licenses/LICENSE-2.0)
|
|
//
|
|
// Alternatively, the contents of this file may be used under the terms of
|
|
// the Boost Software License, Version 1.0.
|
|
// (See accompanying file LICENSE-Boost or copy at
|
|
// https://www.boost.org/LICENSE_1_0.txt)
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, this software
|
|
// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
|
|
// KIND, either express or implied.
|
|
|
|
use core::ptr;
|
|
|
|
#[cfg_attr(feature = "no-panic", inline)]
|
|
pub fn div5(x: u64) -> u64 {
|
|
x / 5
|
|
}
|
|
|
|
#[cfg_attr(feature = "no-panic", inline)]
|
|
pub fn div10(x: u64) -> u64 {
|
|
x / 10
|
|
}
|
|
|
|
#[cfg_attr(feature = "no-panic", inline)]
|
|
pub fn div100(x: u64) -> u64 {
|
|
x / 100
|
|
}
|
|
|
|
#[cfg_attr(feature = "no-panic", inline)]
|
|
fn pow5_factor(mut value: u64) -> u32 {
|
|
let mut count = 0u32;
|
|
loop {
|
|
debug_assert!(value != 0);
|
|
let q = div5(value);
|
|
let r = (value as u32).wrapping_sub(5u32.wrapping_mul(q as u32));
|
|
if r != 0 {
|
|
break;
|
|
}
|
|
value = q;
|
|
count += 1;
|
|
}
|
|
count
|
|
}
|
|
|
|
// Returns true if value is divisible by 5^p.
|
|
#[cfg_attr(feature = "no-panic", inline)]
|
|
pub fn multiple_of_power_of_5(value: u64, p: u32) -> bool {
|
|
// I tried a case distinction on p, but there was no performance difference.
|
|
pow5_factor(value) >= p
|
|
}
|
|
|
|
// Returns true if value is divisible by 2^p.
|
|
#[cfg_attr(feature = "no-panic", inline)]
|
|
pub fn multiple_of_power_of_2(value: u64, p: u32) -> bool {
|
|
debug_assert!(value != 0);
|
|
debug_assert!(p < 64);
|
|
// __builtin_ctzll doesn't appear to be faster here.
|
|
(value & ((1u64 << p) - 1)) == 0
|
|
}
|
|
|
|
#[cfg_attr(feature = "no-panic", inline)]
|
|
pub fn mul_shift_64(m: u64, mul: &(u64, u64), j: u32) -> u64 {
|
|
let b0 = m as u128 * mul.0 as u128;
|
|
let b2 = m as u128 * mul.1 as u128;
|
|
(((b0 >> 64) + b2) >> (j - 64)) as u64
|
|
}
|
|
|
|
#[cfg_attr(feature = "no-panic", inline)]
|
|
pub unsafe fn mul_shift_all_64(
|
|
m: u64,
|
|
mul: &(u64, u64),
|
|
j: u32,
|
|
vp: *mut u64,
|
|
vm: *mut u64,
|
|
mm_shift: u32,
|
|
) -> u64 {
|
|
ptr::write(vp, mul_shift_64(4 * m + 2, mul, j));
|
|
ptr::write(vm, mul_shift_64(4 * m - 1 - mm_shift as u64, mul, j));
|
|
mul_shift_64(4 * m, mul, j)
|
|
}
|