mirror of https://github.com/poanetwork/hbbft.git
96 lines
2.3 KiB
Rust
96 lines
2.3 KiB
Rust
//! A single-byte representation of a set of boolean values.
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use rand_derive::Rand;
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use serde::{Deserialize, Serialize};
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/// The empty set of boolean values.
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pub const NONE: BoolSet = BoolSet(0b00);
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/// The set containing only `false`.
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pub const FALSE: BoolSet = BoolSet(0b01);
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/// The set containing only `true`.
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pub const TRUE: BoolSet = BoolSet(0b10);
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/// The set of both boolean values, `false` and `true`.
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pub const BOTH: BoolSet = BoolSet(0b11);
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/// A set of `bool` values, represented as a single byte in memory.
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#[derive(
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Serialize, Deserialize, Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Rand, Default,
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)]
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pub struct BoolSet(u8);
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impl BoolSet {
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/// Inserts a boolean value into the `BoolSet` and returns `true` iff the `BoolSet` has
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/// changed as a result.
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pub fn insert(&mut self, b: bool) -> bool {
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let prev = *self;
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self.0 |= Self::from(b).0;
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prev != *self
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}
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/// Removes a value from the set.
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pub fn remove(&mut self, b: bool) {
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self.0 &= Self::from(!b).0;
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}
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/// Returns `true` if the set contains the value `b`.
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pub fn contains(self, b: bool) -> bool {
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self.0 & Self::from(b).0 != 0
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}
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/// Returns `true` if every element of `self` is also an element of `other`.
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pub fn is_subset(self, other: BoolSet) -> bool {
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self.0 & other.0 == self.0
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}
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/// Returns `Some(b)` if the set is the singleton with the value `b`, otherwise `None`.
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pub fn definite(self) -> Option<bool> {
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match self {
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FALSE => Some(false),
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TRUE => Some(true),
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_ => None,
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}
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}
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}
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impl From<bool> for BoolSet {
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fn from(b: bool) -> Self {
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if b {
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TRUE
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} else {
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FALSE
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}
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}
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}
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/// An iterator over a `BoolSet`.
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#[derive(Clone, Copy, Debug)]
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pub struct BoolSetIter(BoolSet);
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impl Iterator for BoolSetIter {
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type Item = bool;
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fn next(&mut self) -> Option<bool> {
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if self.0.contains(true) {
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self.0.remove(true);
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Some(true)
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} else if self.0.contains(false) {
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self.0.remove(false);
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Some(false)
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} else {
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None
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}
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}
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}
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impl IntoIterator for BoolSet {
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type Item = bool;
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type IntoIter = BoolSetIter;
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fn into_iter(self) -> Self::IntoIter {
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BoolSetIter(self)
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}
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}
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