vendor/rayon/src/iter/map_with.rs

   1 use super::plumbing::*;
   2 use super::*;
   3
   4 use std::fmt::{self, Debug};
   5
   6 /// `MapWith` is an iterator that transforms the elements of an underlying iterator.
   7 ///
   8 /// This struct is created by the [`map_with()`] method on [`ParallelIterator`]
   9 ///
  10 /// [`map_with()`]: trait.ParallelIterator.html#method.map_with
  11 /// [`ParallelIterator`]: trait.ParallelIterator.html
  12 #[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
  13 #[derive(Clone)]
  14 pub struct MapWith<I: ParallelIterator, T, F> {
  15     base: I,
  16     item: T,
  17     map_op: F,
  18 }
  19
  20 impl<I: ParallelIterator + Debug, T: Debug, F> Debug for MapWith<I, T, F> {
  21     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  22         f.debug_struct("MapWith")
  23             .field("base", &self.base)
  24             .field("item", &self.item)
  25             .finish()
  26     }
  27 }
  28
  29 impl<I, T, F> MapWith<I, T, F>
  30 where
  31     I: ParallelIterator,
  32 {
  33     /// Create a new `MapWith` iterator.
  34     pub(super) fn new(base: I, item: T, map_op: F) -> Self {
  35         MapWith { base, item, map_op }
  36     }
  37 }
  38
  39 impl<I, T, F, R> ParallelIterator for MapWith<I, T, F>
  40 where
  41     I: ParallelIterator,
  42     T: Send + Clone,
  43     F: Fn(&mut T, I::Item) -> R + Sync + Send,
  44     R: Send,
  45 {
  46     type Item = R;
  47
  48     fn drive_unindexed<C>(self, consumer: C) -> C::Result
  49     where
  50         C: UnindexedConsumer<Self::Item>,
  51     {
  52         let consumer1 = MapWithConsumer::new(consumer, self.item, &self.map_op);
  53         self.base.drive_unindexed(consumer1)
  54     }
  55
  56     fn opt_len(&self) -> Option<usize> {
  57         self.base.opt_len()
  58     }
  59 }
  60
  61 impl<I, T, F, R> IndexedParallelIterator for MapWith<I, T, F>
  62 where
  63     I: IndexedParallelIterator,
  64     T: Send + Clone,
  65     F: Fn(&mut T, I::Item) -> R + Sync + Send,
  66     R: Send,
  67 {
  68     fn drive<C>(self, consumer: C) -> C::Result
  69     where
  70         C: Consumer<Self::Item>,
  71     {
  72         let consumer1 = MapWithConsumer::new(consumer, self.item, &self.map_op);
  73         self.base.drive(consumer1)
  74     }
  75
  76     fn len(&self) -> usize {
  77         self.base.len()
  78     }
  79
  80     fn with_producer<CB>(self, callback: CB) -> CB::Output
  81     where
  82         CB: ProducerCallback<Self::Item>,
  83     {
  84         return self.base.with_producer(Callback {
  85             callback,
  86             item: self.item,
  87             map_op: self.map_op,
  88         });
  89
  90         struct Callback<CB, U, F> {
  91             callback: CB,
  92             item: U,
  93             map_op: F,
  94         }
  95
  96         impl<T, U, F, R, CB> ProducerCallback<T> for Callback<CB, U, F>
  97         where
  98             CB: ProducerCallback<R>,
  99             U: Send + Clone,
 100             F: Fn(&mut U, T) -> R + Sync,
 101             R: Send,
 102         {
 103             type Output = CB::Output;
 104
 105             fn callback<P>(self, base: P) -> CB::Output
 106             where
 107                 P: Producer<Item = T>,
 108             {
 109                 let producer = MapWithProducer {
 110                     base,
 111                     item: self.item,
 112                     map_op: &self.map_op,
 113                 };
 114                 self.callback.callback(producer)
 115             }
 116         }
 117     }
 118 }
 119
 120 /// ////////////////////////////////////////////////////////////////////////
 121
 122 struct MapWithProducer<'f, P, U, F: 'f> {
 123     base: P,
 124     item: U,
 125     map_op: &'f F,
 126 }
 127
 128 impl<'f, P, U, F, R> Producer for MapWithProducer<'f, P, U, F>
 129 where
 130     P: Producer,
 131     U: Send + Clone,
 132     F: Fn(&mut U, P::Item) -> R + Sync,
 133     R: Send,
 134 {
 135     type Item = R;
 136     type IntoIter = MapWithIter<'f, P::IntoIter, U, F>;
 137
 138     fn into_iter(self) -> Self::IntoIter {
 139         MapWithIter {
 140             base: self.base.into_iter(),
 141             item: self.item,
 142             map_op: self.map_op,
 143         }
 144     }
 145
 146     fn min_len(&self) -> usize {
 147         self.base.min_len()
 148     }
 149     fn max_len(&self) -> usize {
 150         self.base.max_len()
 151     }
 152
 153     fn split_at(self, index: usize) -> (Self, Self) {
 154         let (left, right) = self.base.split_at(index);
 155         (
 156             MapWithProducer {
 157                 base: left,
 158                 item: self.item.clone(),
 159                 map_op: self.map_op,
 160             },
 161             MapWithProducer {
 162                 base: right,
 163                 item: self.item,
 164                 map_op: self.map_op,
 165             },
 166         )
 167     }
 168
 169     fn fold_with<G>(self, folder: G) -> G
 170     where
 171         G: Folder<Self::Item>,
 172     {
 173         let folder1 = MapWithFolder {
 174             base: folder,
 175             item: self.item,
 176             map_op: self.map_op,
 177         };
 178         self.base.fold_with(folder1).base
 179     }
 180 }
 181
 182 struct MapWithIter<'f, I, U, F: 'f> {
 183     base: I,
 184     item: U,
 185     map_op: &'f F,
 186 }
 187
 188 impl<'f, I, U, F, R> Iterator for MapWithIter<'f, I, U, F>
 189 where
 190     I: Iterator,
 191     F: Fn(&mut U, I::Item) -> R + Sync,
 192     R: Send,
 193 {
 194     type Item = R;
 195
 196     fn next(&mut self) -> Option<R> {
 197         let item = self.base.next()?;
 198         Some((self.map_op)(&mut self.item, item))
 199     }
 200
 201     fn size_hint(&self) -> (usize, Option<usize>) {
 202         self.base.size_hint()
 203     }
 204 }
 205
 206 impl<'f, I, U, F, R> DoubleEndedIterator for MapWithIter<'f, I, U, F>
 207 where
 208     I: DoubleEndedIterator,
 209     F: Fn(&mut U, I::Item) -> R + Sync,
 210     R: Send,
 211 {
 212     fn next_back(&mut self) -> Option<R> {
 213         let item = self.base.next_back()?;
 214         Some((self.map_op)(&mut self.item, item))
 215     }
 216 }
 217
 218 impl<'f, I, U, F, R> ExactSizeIterator for MapWithIter<'f, I, U, F>
 219 where
 220     I: ExactSizeIterator,
 221     F: Fn(&mut U, I::Item) -> R + Sync,
 222     R: Send,
 223 {
 224 }
 225
 226 /// ////////////////////////////////////////////////////////////////////////
 227 /// Consumer implementation
 228
 229 struct MapWithConsumer<'f, C, U, F: 'f> {
 230     base: C,
 231     item: U,
 232     map_op: &'f F,
 233 }
 234
 235 impl<'f, C, U, F> MapWithConsumer<'f, C, U, F> {
 236     fn new(base: C, item: U, map_op: &'f F) -> Self {
 237         MapWithConsumer { base, item, map_op }
 238     }
 239 }
 240
 241 impl<'f, T, U, R, C, F> Consumer<T> for MapWithConsumer<'f, C, U, F>
 242 where
 243     C: Consumer<R>,
 244     U: Send + Clone,
 245     F: Fn(&mut U, T) -> R + Sync,
 246     R: Send,
 247 {
 248     type Folder = MapWithFolder<'f, C::Folder, U, F>;
 249     type Reducer = C::Reducer;
 250     type Result = C::Result;
 251
 252     fn split_at(self, index: usize) -> (Self, Self, Self::Reducer) {
 253         let (left, right, reducer) = self.base.split_at(index);
 254         (
 255             MapWithConsumer::new(left, self.item.clone(), self.map_op),
 256             MapWithConsumer::new(right, self.item, self.map_op),
 257             reducer,
 258         )
 259     }
 260
 261     fn into_folder(self) -> Self::Folder {
 262         MapWithFolder {
 263             base: self.base.into_folder(),
 264             item: self.item,
 265             map_op: self.map_op,
 266         }
 267     }
 268
 269     fn full(&self) -> bool {
 270         self.base.full()
 271     }
 272 }
 273
 274 impl<'f, T, U, R, C, F> UnindexedConsumer<T> for MapWithConsumer<'f, C, U, F>
 275 where
 276     C: UnindexedConsumer<R>,
 277     U: Send + Clone,
 278     F: Fn(&mut U, T) -> R + Sync,
 279     R: Send,
 280 {
 281     fn split_off_left(&self) -> Self {
 282         MapWithConsumer::new(self.base.split_off_left(), self.item.clone(), self.map_op)
 283     }
 284
 285     fn to_reducer(&self) -> Self::Reducer {
 286         self.base.to_reducer()
 287     }
 288 }
 289
 290 struct MapWithFolder<'f, C, U, F: 'f> {
 291     base: C,
 292     item: U,
 293     map_op: &'f F,
 294 }
 295
 296 impl<'f, T, U, R, C, F> Folder<T> for MapWithFolder<'f, C, U, F>
 297 where
 298     C: Folder<R>,
 299     F: Fn(&mut U, T) -> R,
 300 {
 301     type Result = C::Result;
 302
 303     fn consume(mut self, item: T) -> Self {
 304         let mapped_item = (self.map_op)(&mut self.item, item);
 305         self.base = self.base.consume(mapped_item);
 306         self
 307     }
 308
 309     fn consume_iter<I>(mut self, iter: I) -> Self
 310     where
 311         I: IntoIterator<Item = T>,
 312     {
 313         fn with<'f, T, U, R>(
 314             item: &'f mut U,
 315             map_op: impl Fn(&mut U, T) -> R + 'f,
 316         ) -> impl FnMut(T) -> R + 'f {
 317             move |x| map_op(item, x)
 318         }
 319
 320         {
 321             let mapped_iter = iter.into_iter().map(with(&mut self.item, self.map_op));
 322             self.base = self.base.consume_iter(mapped_iter);
 323         }
 324         self
 325     }
 326
 327     fn complete(self) -> C::Result {
 328         self.base.complete()
 329     }
 330
 331     fn full(&self) -> bool {
 332         self.base.full()
 333     }
 334 }
 335
 336 // ------------------------------------------------------------------------------------------------
 337
 338 /// `MapInit` is an iterator that transforms the elements of an underlying iterator.
 339 ///
 340 /// This struct is created by the [`map_init()`] method on [`ParallelIterator`]
 341 ///
 342 /// [`map_init()`]: trait.ParallelIterator.html#method.map_init
 343 /// [`ParallelIterator`]: trait.ParallelIterator.html
 344 #[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
 345 #[derive(Clone)]
 346 pub struct MapInit<I: ParallelIterator, INIT, F> {
 347     base: I,
 348     init: INIT,
 349     map_op: F,
 350 }
 351
 352 impl<I: ParallelIterator + Debug, INIT, F> Debug for MapInit<I, INIT, F> {
 353     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 354         f.debug_struct("MapInit").field("base", &self.base).finish()
 355     }
 356 }
 357
 358 impl<I, INIT, F> MapInit<I, INIT, F>
 359 where
 360     I: ParallelIterator,
 361 {
 362     /// Create a new `MapInit` iterator.
 363     pub(super) fn new(base: I, init: INIT, map_op: F) -> Self {
 364         MapInit { base, init, map_op }
 365     }
 366 }
 367
 368 impl<I, INIT, T, F, R> ParallelIterator for MapInit<I, INIT, F>
 369 where
 370     I: ParallelIterator,
 371     INIT: Fn() -> T + Sync + Send,
 372     F: Fn(&mut T, I::Item) -> R + Sync + Send,
 373     R: Send,
 374 {
 375     type Item = R;
 376
 377     fn drive_unindexed<C>(self, consumer: C) -> C::Result
 378     where
 379         C: UnindexedConsumer<Self::Item>,
 380     {
 381         let consumer1 = MapInitConsumer::new(consumer, &self.init, &self.map_op);
 382         self.base.drive_unindexed(consumer1)
 383     }
 384
 385     fn opt_len(&self) -> Option<usize> {
 386         self.base.opt_len()
 387     }
 388 }
 389
 390 impl<I, INIT, T, F, R> IndexedParallelIterator for MapInit<I, INIT, F>
 391 where
 392     I: IndexedParallelIterator,
 393     INIT: Fn() -> T + Sync + Send,
 394     F: Fn(&mut T, I::Item) -> R + Sync + Send,
 395     R: Send,
 396 {
 397     fn drive<C>(self, consumer: C) -> C::Result
 398     where
 399         C: Consumer<Self::Item>,
 400     {
 401         let consumer1 = MapInitConsumer::new(consumer, &self.init, &self.map_op);
 402         self.base.drive(consumer1)
 403     }
 404
 405     fn len(&self) -> usize {
 406         self.base.len()
 407     }
 408
 409     fn with_producer<CB>(self, callback: CB) -> CB::Output
 410     where
 411         CB: ProducerCallback<Self::Item>,
 412     {
 413         return self.base.with_producer(Callback {
 414             callback,
 415             init: self.init,
 416             map_op: self.map_op,
 417         });
 418
 419         struct Callback<CB, INIT, F> {
 420             callback: CB,
 421             init: INIT,
 422             map_op: F,
 423         }
 424
 425         impl<T, INIT, U, F, R, CB> ProducerCallback<T> for Callback<CB, INIT, F>
 426         where
 427             CB: ProducerCallback<R>,
 428             INIT: Fn() -> U + Sync,
 429             F: Fn(&mut U, T) -> R + Sync,
 430             R: Send,
 431         {
 432             type Output = CB::Output;
 433
 434             fn callback<P>(self, base: P) -> CB::Output
 435             where
 436                 P: Producer<Item = T>,
 437             {
 438                 let producer = MapInitProducer {
 439                     base,
 440                     init: &self.init,
 441                     map_op: &self.map_op,
 442                 };
 443                 self.callback.callback(producer)
 444             }
 445         }
 446     }
 447 }
 448
 449 /// ////////////////////////////////////////////////////////////////////////
 450
 451 struct MapInitProducer<'f, P, INIT: 'f, F: 'f> {
 452     base: P,
 453     init: &'f INIT,
 454     map_op: &'f F,
 455 }
 456
 457 impl<'f, P, INIT, U, F, R> Producer for MapInitProducer<'f, P, INIT, F>
 458 where
 459     P: Producer,
 460     INIT: Fn() -> U + Sync,
 461     F: Fn(&mut U, P::Item) -> R + Sync,
 462     R: Send,
 463 {
 464     type Item = R;
 465     type IntoIter = MapWithIter<'f, P::IntoIter, U, F>;
 466
 467     fn into_iter(self) -> Self::IntoIter {
 468         MapWithIter {
 469             base: self.base.into_iter(),
 470             item: (self.init)(),
 471             map_op: self.map_op,
 472         }
 473     }
 474
 475     fn min_len(&self) -> usize {
 476         self.base.min_len()
 477     }
 478     fn max_len(&self) -> usize {
 479         self.base.max_len()
 480     }
 481
 482     fn split_at(self, index: usize) -> (Self, Self) {
 483         let (left, right) = self.base.split_at(index);
 484         (
 485             MapInitProducer {
 486                 base: left,
 487                 init: self.init,
 488                 map_op: self.map_op,
 489             },
 490             MapInitProducer {
 491                 base: right,
 492                 init: self.init,
 493                 map_op: self.map_op,
 494             },
 495         )
 496     }
 497
 498     fn fold_with<G>(self, folder: G) -> G
 499     where
 500         G: Folder<Self::Item>,
 501     {
 502         let folder1 = MapWithFolder {
 503             base: folder,
 504             item: (self.init)(),
 505             map_op: self.map_op,
 506         };
 507         self.base.fold_with(folder1).base
 508     }
 509 }
 510
 511 /// ////////////////////////////////////////////////////////////////////////
 512 /// Consumer implementation
 513
 514 struct MapInitConsumer<'f, C, INIT: 'f, F: 'f> {
 515     base: C,
 516     init: &'f INIT,
 517     map_op: &'f F,
 518 }
 519
 520 impl<'f, C, INIT, F> MapInitConsumer<'f, C, INIT, F> {
 521     fn new(base: C, init: &'f INIT, map_op: &'f F) -> Self {
 522         MapInitConsumer { base, init, map_op }
 523     }
 524 }
 525
 526 impl<'f, T, INIT, U, R, C, F> Consumer<T> for MapInitConsumer<'f, C, INIT, F>
 527 where
 528     C: Consumer<R>,
 529     INIT: Fn() -> U + Sync,
 530     F: Fn(&mut U, T) -> R + Sync,
 531     R: Send,
 532 {
 533     type Folder = MapWithFolder<'f, C::Folder, U, F>;
 534     type Reducer = C::Reducer;
 535     type Result = C::Result;
 536
 537     fn split_at(self, index: usize) -> (Self, Self, Self::Reducer) {
 538         let (left, right, reducer) = self.base.split_at(index);
 539         (
 540             MapInitConsumer::new(left, self.init, self.map_op),
 541             MapInitConsumer::new(right, self.init, self.map_op),
 542             reducer,
 543         )
 544     }
 545
 546     fn into_folder(self) -> Self::Folder {
 547         MapWithFolder {
 548             base: self.base.into_folder(),
 549             item: (self.init)(),
 550             map_op: self.map_op,
 551         }
 552     }
 553
 554     fn full(&self) -> bool {
 555         self.base.full()
 556     }
 557 }
 558
 559 impl<'f, T, INIT, U, R, C, F> UnindexedConsumer<T> for MapInitConsumer<'f, C, INIT, F>
 560 where
 561     C: UnindexedConsumer<R>,
 562     INIT: Fn() -> U + Sync,
 563     F: Fn(&mut U, T) -> R + Sync,
 564     R: Send,
 565 {
 566     fn split_off_left(&self) -> Self {
 567         MapInitConsumer::new(self.base.split_off_left(), self.init, self.map_op)
 568     }
 569
 570     fn to_reducer(&self) -> Self::Reducer {
 571         self.base.to_reducer()
 572     }
 573 }