1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362
//! This module contains an implementation of a below-exception set. //! //! # Examples //! ``` //! use threshold::*; //! //! let mut below_exset = BelowExSet::new(); //! assert_eq!(below_exset.next_event(), 1); //! assert!(below_exset.is_event(1)); //! assert!(!below_exset.is_event(2)); //! //! let other = BelowExSet::from_event(3); //! assert!(!other.is_event(1)); //! assert!(!other.is_event(2)); //! assert!(other.is_event(3)); //! //! below_exset.join(&other); //! assert!(below_exset.is_event(1)); //! assert!(!below_exset.is_event(2)); //! assert!(below_exset.is_event(3)); //! ``` use crate::EventSet; use serde::{Deserialize, Serialize}; use std::cmp::{self, Ordering}; use std::collections::HashSet; use std::fmt; use std::iter::FromIterator; #[derive(Clone, PartialEq, Eq, Default, Serialize, Deserialize)] pub struct BelowExSet { // Highest event seen max: u64, // Set of exceptions exs: HashSet<u64>, } impl EventSet for BelowExSet { type EventIter = EventIter; /// Returns a new `BelowExSet` instance. fn new() -> Self { BelowExSet { max: 0, exs: HashSet::new(), } } /// Generates the next event. /// There should be no exceptions when calling this. /// /// # Examples /// ``` /// use threshold::*; /// /// let mut below_exset = BelowExSet::new(); /// assert_eq!(below_exset.next_event(), 1); /// assert_eq!(below_exset.next_event(), 2); /// ``` fn next_event(&mut self) -> u64 { debug_assert!(self.exs.is_empty()); self.max += 1; self.max } /// Adds an event to the set. /// /// # Examples /// ``` /// use threshold::*; /// /// let mut below_exset = BelowExSet::new(); /// /// below_exset.add_event(1); /// assert!(below_exset.is_event(1)); /// assert!(!below_exset.is_event(2)); /// /// below_exset.add_event(3); /// assert!(below_exset.is_event(1)); /// assert!(!below_exset.is_event(2)); /// assert!(below_exset.is_event(3)); /// /// below_exset.add_event(2); /// assert!(below_exset.is_event(1)); /// assert!(below_exset.is_event(2)); /// assert!(below_exset.is_event(3)); /// ``` fn add_event(&mut self, event: u64) -> bool { match event.cmp(&self.max) { Ordering::Less => { // remove from exceptions (it might not be an exception though). // the result is the same as the result of the remove in the // exceptions: // - if it was an exception, then it's also a new event self.exs.remove(&event) } Ordering::Greater => { // this event is now the new max, which might create exceptions for new_ex in self.max + 1..event { self.exs.insert(new_ex); } self.max = event; // new event, so `true` true } Ordering::Equal => { // nothing to do since it is already an event false } } } /// Checks if an event is part of the set. /// /// # Examples /// ``` /// use threshold::*; /// /// let mut below_exset = BelowExSet::new(); /// let event = below_exset.next_event(); /// assert!(below_exset.is_event(event)); /// /// below_exset.add_event(3); /// assert!(!below_exset.is_event(2)); /// assert!(below_exset.is_event(3)); /// ``` fn is_event(&self, event: u64) -> bool { event <= self.max && !self.exs.contains(&event) } /// Returns all events seen as a tuple. /// The first component is the highest event seen, while the second is a /// vector with the exceptions (in no specific order). /// /// # Examples /// ``` /// use threshold::*; /// /// let mut below_exset = BelowExSet::new(); /// /// below_exset.add_event(1); /// assert_eq!(below_exset.events(), (1, vec![])); /// /// below_exset.add_event(3); /// assert_eq!(below_exset.events(), (3, vec![2])); /// /// below_exset.add_event(2); /// assert_eq!(below_exset.events(), (3, vec![])); /// /// below_exset.add_event(4); /// assert_eq!(below_exset.events(), (4, vec![])); /// /// below_exset.add_event(6); /// assert_eq!(below_exset.events(), (6, vec![5])); /// ``` fn events(&self) -> (u64, Vec<u64>) { (self.max, self.exs.clone().into_iter().collect()) } /// Returns the frontier (the highest contiguous event seen). /// /// __Note:__ this method's implementation will sort all exceptions on each /// call, and with that, the performance will not be great. If this /// becomes a problem, we could cache the frontier (as in `AboveExSet`) /// so that it doesn't have to be computed here on each call. /// /// # Examples /// ``` /// use threshold::*; /// /// let mut below_exset = BelowExSet::new(); /// assert_eq!(below_exset.frontier(), 0); /// /// below_exset.add_event(1); /// assert_eq!(below_exset.frontier(), 1); /// /// below_exset.add_event(3); /// assert_eq!(below_exset.frontier(), 1); /// /// below_exset.add_event(2); /// assert_eq!(below_exset.frontier(), 3); /// /// below_exset.add_event(4); /// assert_eq!(below_exset.frontier(), 4); /// /// below_exset.add_event(6); /// assert_eq!(below_exset.frontier(), 4); /// ``` fn frontier(&self) -> u64 { // if there are no exceptions, then the highest contiguous event is // self.max otherwise, it's the smallest exception - 1 if self.exs.is_empty() { self.max } else { // sort exceptions let mut exs: Vec<_> = self.exs.iter().collect(); exs.sort_unstable(); // return the smallest one -1 (**exs.iter().next().unwrap()) - 1 } } /// Merges `other` `BelowExSet` into `self`. /// /// # Examples /// ``` /// use threshold::*; /// /// let mut below_exset = BelowExSet::new(); /// below_exset.add_event(1); /// below_exset.add_event(3); /// below_exset.add_event(4); /// assert_eq!(below_exset.events(), (4, vec![2])); /// /// below_exset.join(&BelowExSet::from_event(3)); /// assert_eq!(below_exset.events(), (4, vec![2])); /// /// below_exset.join(&BelowExSet::from_event(5)); /// assert_eq!(below_exset.events(), (5, vec![2])); /// /// let mut other = BelowExSet::new(); /// other.add_event(2); /// other.add_event(7); /// below_exset.join(&other); /// assert_eq!(below_exset.events(), (7, vec![6])); /// ``` fn join(&mut self, other: &Self) { let before = self.clone(); // the new exceptions are a subset of the union of exceptions sets // - this means that the join does not create new exceptions // // keep the local exceptions that are not remote events self.exs.retain(|ex| !other.is_event(*ex)); // keep the remote exceptions that are not local events other .exs .iter() .filter(|&&ex| !before.is_event(ex)) .for_each(|&ex| { self.exs.insert(ex); }); // the new max value is the max of both max values self.max = cmp::max(self.max, other.max); } fn meet(&mut self, _other: &Self) { todo!("BelowExSet::meet not yet implemented") } /// Returns a `BelowExSet` event iterator with all events from lowest to /// highest. /// /// # Examples /// ``` /// use threshold::*; /// /// let mut below_exset = BelowExSet::new(); /// below_exset.add_event(3); /// below_exset.add_event(5); /// /// let mut iter = below_exset.event_iter(); /// assert_eq!(iter.next(), Some(3)); /// assert_eq!(iter.next(), Some(5)); /// assert_eq!(iter.next(), None); /// ``` fn event_iter(self) -> Self::EventIter { EventIter { current: 0, max: self.max, exs: self.exs, } } } impl BelowExSet { /// Creates a new instance from the highest event, and a sequence of /// exceptions. /// /// # Examples /// ``` /// use threshold::*; /// /// let below_exset = BelowExSet::from(5, vec![1, 3]); /// assert!(!below_exset.is_event(1)); /// assert!(below_exset.is_event(2)); /// assert!(!below_exset.is_event(3)); /// assert!(below_exset.is_event(4)); /// assert!(below_exset.is_event(5)); /// assert!(!below_exset.is_event(6)); /// ``` pub fn from<I: IntoIterator<Item = u64>>(max: u64, iter: I) -> Self { BelowExSet { max, exs: HashSet::from_iter(iter), } } } pub struct EventIter { // Last value returned by the iterator current: u64, // Last value that should be returned by the iterator max: u64, // Set of exceptions to be skipped by the iterator exs: HashSet<u64>, } impl Iterator for EventIter { type Item = u64; fn next(&mut self) -> Option<Self::Item> { if self.current == self.max { // we've reached the end of the iterator None } else { // compute next value self.current += 1; if self.exs.contains(&self.current) { // if the next value is an exception, skip it self.next() } else { // otherwise, return it Some(self.current) } } } } impl fmt::Debug for BelowExSet { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { if self.exs.is_empty() { write!(f, "{}", self.max) } else { write!(f, "({} - {:?})", self.max, self.exs) } } } #[cfg(test)] mod tests { use super::*; #[test] fn range() { // add event 1 and 2 to eset let mut eset = BelowExSet::new(); eset.add_event(1); eset.add_event(2); // create range let start = 1; let end = 2; // check it's the same assert_eq!(eset, BelowExSet::from_event_range(start, end)); } }