70 lines
1.7 KiB
Rust
70 lines
1.7 KiB
Rust
//! limit defines a struct to enforce limits.
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#![warn(rust_2018_idioms, unused_lifetimes)]
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#[cfg(feature = "tracking")]
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use std::sync::atomic::AtomicUsize;
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/// Represents a struct used to enforce a numerical limit.
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#[derive(Debug)]
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pub struct Limit {
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upper_bound: usize,
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#[cfg(feature = "tracking")]
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max: AtomicUsize,
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}
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impl Limit {
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/// Creates a new limit.
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#[inline]
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pub const fn new(upper_bound: usize) -> Self {
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Self {
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upper_bound,
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#[cfg(feature = "tracking")]
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max: AtomicUsize::new(0),
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}
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}
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/// Creates a new limit.
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#[inline]
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#[cfg(feature = "tracking")]
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pub const fn new_tracking(upper_bound: usize) -> Self {
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Self {
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upper_bound,
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#[cfg(feature = "tracking")]
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max: AtomicUsize::new(1),
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}
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}
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/// Gets the underlying numeric limit.
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#[inline]
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pub const fn inner(&self) -> usize {
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self.upper_bound
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}
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/// Checks whether the given value is below the limit.
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/// Returns `Ok` when `other` is below `self`, and `Err` otherwise.
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#[inline]
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pub fn check(&self, other: usize) -> Result<(), ()> {
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if other > self.upper_bound {
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Err(())
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} else {
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#[cfg(feature = "tracking")]
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loop {
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use std::sync::atomic::Ordering;
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let old_max = self.max.load(Ordering::Relaxed);
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if other <= old_max || old_max == 0 {
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break;
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}
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_ = self.max.compare_exchange_weak(
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old_max,
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other,
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Ordering::Relaxed,
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Ordering::Relaxed,
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);
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}
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Ok(())
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}
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}
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}
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