core/
range.rs

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
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
//! # Experimental replacement range types
//!
//! The types within this module are meant to replace the existing
//! `Range`, `RangeInclusive`, and `RangeFrom` types in a future edition.
//!
//! ```
//! #![feature(new_range_api)]
//! use core::range::{Range, RangeFrom, RangeInclusive};
//!
//! let arr = [0, 1, 2, 3, 4];
//! assert_eq!(arr[                      ..   ], [0, 1, 2, 3, 4]);
//! assert_eq!(arr[                      .. 3 ], [0, 1, 2      ]);
//! assert_eq!(arr[                      ..=3 ], [0, 1, 2, 3   ]);
//! assert_eq!(arr[     RangeFrom::from(1..  )], [   1, 2, 3, 4]);
//! assert_eq!(arr[         Range::from(1..3 )], [   1, 2      ]);
//! assert_eq!(arr[RangeInclusive::from(1..=3)], [   1, 2, 3   ]);
//! ```

use crate::fmt;
use crate::hash::Hash;

mod iter;

#[unstable(feature = "new_range_api", issue = "125687")]
pub mod legacy;

#[doc(inline)]
pub use iter::{IterRange, IterRangeFrom, IterRangeInclusive};
use Bound::{Excluded, Included, Unbounded};

#[doc(inline)]
pub use crate::iter::Step;
#[doc(inline)]
pub use crate::ops::{Bound, OneSidedRange, RangeBounds, RangeFull, RangeTo, RangeToInclusive};

/// A (half-open) range bounded inclusively below and exclusively above
/// (`start..end` in a future edition).
///
/// The range `start..end` contains all values with `start <= x < end`.
/// It is empty if `start >= end`.
///
/// # Examples
///
/// ```
/// #![feature(new_range_api)]
/// use core::range::Range;
///
/// assert_eq!(Range::from(3..5), Range { start: 3, end: 5 });
/// assert_eq!(3 + 4 + 5, Range::from(3..6).into_iter().sum());
/// ```
#[derive(Clone, Copy, Default, PartialEq, Eq, Hash)]
#[unstable(feature = "new_range_api", issue = "125687")]
pub struct Range<Idx> {
    /// The lower bound of the range (inclusive).
    #[unstable(feature = "new_range_api", issue = "125687")]
    pub start: Idx,
    /// The upper bound of the range (exclusive).
    #[unstable(feature = "new_range_api", issue = "125687")]
    pub end: Idx,
}

#[unstable(feature = "new_range_api", issue = "125687")]
impl<Idx: fmt::Debug> fmt::Debug for Range<Idx> {
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        self.start.fmt(fmt)?;
        write!(fmt, "..")?;
        self.end.fmt(fmt)?;
        Ok(())
    }
}

impl<Idx: Step> Range<Idx> {
    /// Creates an iterator over the elements within this range.
    ///
    /// Shorthand for `.clone().into_iter()`
    ///
    /// # Examples
    ///
    /// ```
    /// #![feature(new_range_api)]
    /// use core::range::Range;
    ///
    /// let mut i = Range::from(3..9).iter().map(|n| n*n);
    /// assert_eq!(i.next(), Some(9));
    /// assert_eq!(i.next(), Some(16));
    /// assert_eq!(i.next(), Some(25));
    /// ```
    #[unstable(feature = "new_range_api", issue = "125687")]
    #[inline]
    pub fn iter(&self) -> IterRange<Idx> {
        self.clone().into_iter()
    }
}

impl<Idx: PartialOrd<Idx>> Range<Idx> {
    /// Returns `true` if `item` is contained in the range.
    ///
    /// # Examples
    ///
    /// ```
    /// #![feature(new_range_api)]
    /// use core::range::Range;
    ///
    /// assert!(!Range::from(3..5).contains(&2));
    /// assert!( Range::from(3..5).contains(&3));
    /// assert!( Range::from(3..5).contains(&4));
    /// assert!(!Range::from(3..5).contains(&5));
    ///
    /// assert!(!Range::from(3..3).contains(&3));
    /// assert!(!Range::from(3..2).contains(&3));
    ///
    /// assert!( Range::from(0.0..1.0).contains(&0.5));
    /// assert!(!Range::from(0.0..1.0).contains(&f32::NAN));
    /// assert!(!Range::from(0.0..f32::NAN).contains(&0.5));
    /// assert!(!Range::from(f32::NAN..1.0).contains(&0.5));
    /// ```
    #[inline]
    #[unstable(feature = "new_range_api", issue = "125687")]
    pub fn contains<U>(&self, item: &U) -> bool
    where
        Idx: PartialOrd<U>,
        U: ?Sized + PartialOrd<Idx>,
    {
        <Self as RangeBounds<Idx>>::contains(self, item)
    }

    /// Returns `true` if the range contains no items.
    ///
    /// # Examples
    ///
    /// ```
    /// #![feature(new_range_api)]
    /// use core::range::Range;
    ///
    /// assert!(!Range::from(3..5).is_empty());
    /// assert!( Range::from(3..3).is_empty());
    /// assert!( Range::from(3..2).is_empty());
    /// ```
    ///
    /// The range is empty if either side is incomparable:
    ///
    /// ```
    /// #![feature(new_range_api)]
    /// use core::range::Range;
    ///
    /// assert!(!Range::from(3.0..5.0).is_empty());
    /// assert!( Range::from(3.0..f32::NAN).is_empty());
    /// assert!( Range::from(f32::NAN..5.0).is_empty());
    /// ```
    #[inline]
    #[unstable(feature = "new_range_api", issue = "125687")]
    pub fn is_empty(&self) -> bool {
        !(self.start < self.end)
    }
}

#[unstable(feature = "new_range_api", issue = "125687")]
impl<T> RangeBounds<T> for Range<T> {
    fn start_bound(&self) -> Bound<&T> {
        Included(&self.start)
    }
    fn end_bound(&self) -> Bound<&T> {
        Excluded(&self.end)
    }
}

#[unstable(feature = "new_range_api", issue = "125687")]
impl<T> RangeBounds<T> for Range<&T> {
    fn start_bound(&self) -> Bound<&T> {
        Included(self.start)
    }
    fn end_bound(&self) -> Bound<&T> {
        Excluded(self.end)
    }
}

#[unstable(feature = "new_range_api", issue = "125687")]
impl<T> From<Range<T>> for legacy::Range<T> {
    #[inline]
    fn from(value: Range<T>) -> Self {
        Self { start: value.start, end: value.end }
    }
}
#[unstable(feature = "new_range_api", issue = "125687")]
impl<T> From<legacy::Range<T>> for Range<T> {
    #[inline]
    fn from(value: legacy::Range<T>) -> Self {
        Self { start: value.start, end: value.end }
    }
}

/// A range bounded inclusively below and above (`start..=end`).
///
/// The `RangeInclusive` `start..=end` contains all values with `x >= start`
/// and `x <= end`. It is empty unless `start <= end`.
///
/// # Examples
///
/// The `start..=end` syntax is a `RangeInclusive`:
///
/// ```
/// #![feature(new_range_api)]
/// use core::range::RangeInclusive;
///
/// assert_eq!(RangeInclusive::from(3..=5), RangeInclusive { start: 3, end: 5 });
/// assert_eq!(3 + 4 + 5, RangeInclusive::from(3..=5).into_iter().sum());
/// ```
#[derive(Clone, Copy, PartialEq, Eq, Hash)]
#[unstable(feature = "new_range_api", issue = "125687")]
pub struct RangeInclusive<Idx> {
    /// The lower bound of the range (inclusive).
    #[unstable(feature = "new_range_api", issue = "125687")]
    pub start: Idx,
    /// The upper bound of the range (inclusive).
    #[unstable(feature = "new_range_api", issue = "125687")]
    pub end: Idx,
}

#[unstable(feature = "new_range_api", issue = "125687")]
impl<Idx: fmt::Debug> fmt::Debug for RangeInclusive<Idx> {
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        self.start.fmt(fmt)?;
        write!(fmt, "..=")?;
        self.end.fmt(fmt)?;
        Ok(())
    }
}

impl<Idx: PartialOrd<Idx>> RangeInclusive<Idx> {
    /// Returns `true` if `item` is contained in the range.
    ///
    /// # Examples
    ///
    /// ```
    /// #![feature(new_range_api)]
    /// use core::range::RangeInclusive;
    ///
    /// assert!(!RangeInclusive::from(3..=5).contains(&2));
    /// assert!( RangeInclusive::from(3..=5).contains(&3));
    /// assert!( RangeInclusive::from(3..=5).contains(&4));
    /// assert!( RangeInclusive::from(3..=5).contains(&5));
    /// assert!(!RangeInclusive::from(3..=5).contains(&6));
    ///
    /// assert!( RangeInclusive::from(3..=3).contains(&3));
    /// assert!(!RangeInclusive::from(3..=2).contains(&3));
    ///
    /// assert!( RangeInclusive::from(0.0..=1.0).contains(&1.0));
    /// assert!(!RangeInclusive::from(0.0..=1.0).contains(&f32::NAN));
    /// assert!(!RangeInclusive::from(0.0..=f32::NAN).contains(&0.0));
    /// assert!(!RangeInclusive::from(f32::NAN..=1.0).contains(&1.0));
    /// ```
    #[inline]
    #[unstable(feature = "new_range_api", issue = "125687")]
    pub fn contains<U>(&self, item: &U) -> bool
    where
        Idx: PartialOrd<U>,
        U: ?Sized + PartialOrd<Idx>,
    {
        <Self as RangeBounds<Idx>>::contains(self, item)
    }

    /// Returns `true` if the range contains no items.
    ///
    /// # Examples
    ///
    /// ```
    /// #![feature(new_range_api)]
    /// use core::range::RangeInclusive;
    ///
    /// assert!(!RangeInclusive::from(3..=5).is_empty());
    /// assert!(!RangeInclusive::from(3..=3).is_empty());
    /// assert!( RangeInclusive::from(3..=2).is_empty());
    /// ```
    ///
    /// The range is empty if either side is incomparable:
    ///
    /// ```
    /// #![feature(new_range_api)]
    /// use core::range::RangeInclusive;
    ///
    /// assert!(!RangeInclusive::from(3.0..=5.0).is_empty());
    /// assert!( RangeInclusive::from(3.0..=f32::NAN).is_empty());
    /// assert!( RangeInclusive::from(f32::NAN..=5.0).is_empty());
    /// ```
    #[unstable(feature = "new_range_api", issue = "125687")]
    #[inline]
    pub fn is_empty(&self) -> bool {
        !(self.start <= self.end)
    }
}

impl<Idx: Step> RangeInclusive<Idx> {
    /// Creates an iterator over the elements within this range.
    ///
    /// Shorthand for `.clone().into_iter()`
    ///
    /// # Examples
    ///
    /// ```
    /// #![feature(new_range_api)]
    /// use core::range::RangeInclusive;
    ///
    /// let mut i = RangeInclusive::from(3..=8).iter().map(|n| n*n);
    /// assert_eq!(i.next(), Some(9));
    /// assert_eq!(i.next(), Some(16));
    /// assert_eq!(i.next(), Some(25));
    /// ```
    #[unstable(feature = "new_range_api", issue = "125687")]
    #[inline]
    pub fn iter(&self) -> IterRangeInclusive<Idx> {
        self.clone().into_iter()
    }
}

impl RangeInclusive<usize> {
    /// Converts to an exclusive `Range` for `SliceIndex` implementations.
    /// The caller is responsible for dealing with `end == usize::MAX`.
    #[inline]
    pub(crate) const fn into_slice_range(self) -> Range<usize> {
        Range { start: self.start, end: self.end + 1 }
    }
}

#[unstable(feature = "new_range_api", issue = "125687")]
impl<T> RangeBounds<T> for RangeInclusive<T> {
    fn start_bound(&self) -> Bound<&T> {
        Included(&self.start)
    }
    fn end_bound(&self) -> Bound<&T> {
        Included(&self.end)
    }
}

#[unstable(feature = "new_range_api", issue = "125687")]
impl<T> RangeBounds<T> for RangeInclusive<&T> {
    fn start_bound(&self) -> Bound<&T> {
        Included(self.start)
    }
    fn end_bound(&self) -> Bound<&T> {
        Included(self.end)
    }
}

#[unstable(feature = "new_range_api", issue = "125687")]
impl<T> From<RangeInclusive<T>> for legacy::RangeInclusive<T> {
    #[inline]
    fn from(value: RangeInclusive<T>) -> Self {
        Self::new(value.start, value.end)
    }
}
#[unstable(feature = "new_range_api", issue = "125687")]
impl<T> From<legacy::RangeInclusive<T>> for RangeInclusive<T> {
    #[inline]
    fn from(value: legacy::RangeInclusive<T>) -> Self {
        assert!(
            !value.exhausted,
            "attempted to convert from an exhausted `legacy::RangeInclusive` (unspecified behavior)"
        );

        let (start, end) = value.into_inner();
        RangeInclusive { start, end }
    }
}

/// A range only bounded inclusively below (`start..`).
///
/// The `RangeFrom` `start..` contains all values with `x >= start`.
///
/// *Note*: Overflow in the [`Iterator`] implementation (when the contained
/// data type reaches its numerical limit) is allowed to panic, wrap, or
/// saturate. This behavior is defined by the implementation of the [`Step`]
/// trait. For primitive integers, this follows the normal rules, and respects
/// the overflow checks profile (panic in debug, wrap in release). Note also
/// that overflow happens earlier than you might assume: the overflow happens
/// in the call to `next` that yields the maximum value, as the range must be
/// set to a state to yield the next value.
///
/// [`Step`]: crate::iter::Step
///
/// # Examples
///
/// The `start..` syntax is a `RangeFrom`:
///
/// ```
/// #![feature(new_range_api)]
/// use core::range::RangeFrom;
///
/// assert_eq!(RangeFrom::from(2..), core::range::RangeFrom { start: 2 });
/// assert_eq!(2 + 3 + 4, RangeFrom::from(2..).into_iter().take(3).sum());
/// ```
#[derive(Clone, Copy, PartialEq, Eq, Hash)]
#[unstable(feature = "new_range_api", issue = "125687")]
pub struct RangeFrom<Idx> {
    /// The lower bound of the range (inclusive).
    #[unstable(feature = "new_range_api", issue = "125687")]
    pub start: Idx,
}

#[unstable(feature = "new_range_api", issue = "125687")]
impl<Idx: fmt::Debug> fmt::Debug for RangeFrom<Idx> {
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        self.start.fmt(fmt)?;
        write!(fmt, "..")?;
        Ok(())
    }
}

impl<Idx: Step> RangeFrom<Idx> {
    /// Creates an iterator over the elements within this range.
    ///
    /// Shorthand for `.clone().into_iter()`
    ///
    /// # Examples
    ///
    /// ```
    /// #![feature(new_range_api)]
    /// use core::range::RangeFrom;
    ///
    /// let mut i = RangeFrom::from(3..).iter().map(|n| n*n);
    /// assert_eq!(i.next(), Some(9));
    /// assert_eq!(i.next(), Some(16));
    /// assert_eq!(i.next(), Some(25));
    /// ```
    #[unstable(feature = "new_range_api", issue = "125687")]
    #[inline]
    pub fn iter(&self) -> IterRangeFrom<Idx> {
        self.clone().into_iter()
    }
}

impl<Idx: PartialOrd<Idx>> RangeFrom<Idx> {
    /// Returns `true` if `item` is contained in the range.
    ///
    /// # Examples
    ///
    /// ```
    /// #![feature(new_range_api)]
    /// use core::range::RangeFrom;
    ///
    /// assert!(!RangeFrom::from(3..).contains(&2));
    /// assert!( RangeFrom::from(3..).contains(&3));
    /// assert!( RangeFrom::from(3..).contains(&1_000_000_000));
    ///
    /// assert!( RangeFrom::from(0.0..).contains(&0.5));
    /// assert!(!RangeFrom::from(0.0..).contains(&f32::NAN));
    /// assert!(!RangeFrom::from(f32::NAN..).contains(&0.5));
    /// ```
    #[inline]
    #[unstable(feature = "new_range_api", issue = "125687")]
    pub fn contains<U>(&self, item: &U) -> bool
    where
        Idx: PartialOrd<U>,
        U: ?Sized + PartialOrd<Idx>,
    {
        <Self as RangeBounds<Idx>>::contains(self, item)
    }
}

#[unstable(feature = "new_range_api", issue = "125687")]
impl<T> RangeBounds<T> for RangeFrom<T> {
    fn start_bound(&self) -> Bound<&T> {
        Included(&self.start)
    }
    fn end_bound(&self) -> Bound<&T> {
        Unbounded
    }
}

#[unstable(feature = "new_range_api", issue = "125687")]
impl<T> RangeBounds<T> for RangeFrom<&T> {
    fn start_bound(&self) -> Bound<&T> {
        Included(self.start)
    }
    fn end_bound(&self) -> Bound<&T> {
        Unbounded
    }
}

#[unstable(feature = "new_range_api", issue = "125687")]
impl<T> From<RangeFrom<T>> for legacy::RangeFrom<T> {
    #[inline]
    fn from(value: RangeFrom<T>) -> Self {
        Self { start: value.start }
    }
}
#[unstable(feature = "new_range_api", issue = "125687")]
impl<T> From<legacy::RangeFrom<T>> for RangeFrom<T> {
    #[inline]
    fn from(value: legacy::RangeFrom<T>) -> Self {
        Self { start: value.start }
    }
}