bit_set/
lib.rs

1// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
2// file at the top-level directory of this distribution and at
3// http://rust-lang.org/COPYRIGHT.
4//
5// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8// option. This file may not be copied, modified, or distributed
9// except according to those terms.
10
11//! # Description
12//!
13//! An implementation of a set using a bit vector as an underlying
14//! representation for holding unsigned numerical elements.
15//!
16//! It should also be noted that the amount of storage necessary for holding a
17//! set of objects is proportional to the maximum of the objects when viewed
18//! as a `usize`.
19//!
20//! # Examples
21//!
22//! ```
23//! use bit_set::BitSet;
24//!
25//! // It's a regular set
26//! let mut s = BitSet::new();
27//! s.insert(0);
28//! s.insert(3);
29//! s.insert(7);
30//!
31//! s.remove(7);
32//!
33//! if !s.contains(7) {
34//!     println!("There is no 7");
35//! }
36//!
37//! // Can initialize from a `BitVec`
38//! let other = BitSet::from_bytes(&[0b11010000]);
39//!
40//! s.union_with(&other);
41//!
42//! // Print 0, 1, 3 in some order
43//! for x in s.iter() {
44//!     println!("{}", x);
45//! }
46//!
47//! // Can convert back to a `BitVec`
48//! let bv = s.into_bit_vec();
49//! assert!(bv[3]);
50//! ```
51#![doc(html_root_url = "https://docs.rs/bit-set/0.8.0")]
52#![no_std]
53
54extern crate bit_vec;
55
56#[cfg(feature = "serde")]
57extern crate serde;
58
59#[cfg(any(test, feature = "std"))]
60extern crate std;
61
62use bit_vec::{BitBlock, BitVec, Blocks};
63use core::cmp;
64use core::cmp::Ordering;
65use core::fmt;
66use core::hash;
67use core::iter::{self, Chain, Enumerate, FromIterator, Repeat, Skip, Take};
68
69type MatchWords<'a, B> = Chain<Enumerate<Blocks<'a, B>>, Skip<Take<Enumerate<Repeat<B>>>>>;
70
71/// Computes how many blocks are needed to store that many bits
72fn blocks_for_bits<B: BitBlock>(bits: usize) -> usize {
73    // If we want 17 bits, dividing by 32 will produce 0. So we add 1 to make sure we
74    // reserve enough. But if we want exactly a multiple of 32, this will actually allocate
75    // one too many. So we need to check if that's the case. We can do that by computing if
76    // bitwise AND by `32 - 1` is 0. But LLVM should be able to optimize the semantically
77    // superior modulo operator on a power of two to this.
78    //
79    // Note that we can technically avoid this branch with the expression
80    // `(nbits + BITS - 1) / 32::BITS`, but if nbits is almost usize::MAX this will overflow.
81    if bits % B::bits() == 0 {
82        bits / B::bits()
83    } else {
84        bits / B::bits() + 1
85    }
86}
87
88#[allow(clippy::iter_skip_zero)]
89// Take two BitVec's, and return iterators of their words, where the shorter one
90// has been padded with 0's
91fn match_words<'a, 'b, B: BitBlock>(
92    a: &'a BitVec<B>,
93    b: &'b BitVec<B>,
94) -> (MatchWords<'a, B>, MatchWords<'b, B>) {
95    let a_len = a.storage().len();
96    let b_len = b.storage().len();
97
98    // have to uselessly pretend to pad the longer one for type matching
99    if a_len < b_len {
100        (
101            a.blocks()
102                .enumerate()
103                .chain(iter::repeat(B::zero()).enumerate().take(b_len).skip(a_len)),
104            b.blocks()
105                .enumerate()
106                .chain(iter::repeat(B::zero()).enumerate().take(0).skip(0)),
107        )
108    } else {
109        (
110            a.blocks()
111                .enumerate()
112                .chain(iter::repeat(B::zero()).enumerate().take(0).skip(0)),
113            b.blocks()
114                .enumerate()
115                .chain(iter::repeat(B::zero()).enumerate().take(a_len).skip(b_len)),
116        )
117    }
118}
119
120#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
121pub struct BitSet<B = u32> {
122    bit_vec: BitVec<B>,
123}
124
125impl<B: BitBlock> Clone for BitSet<B> {
126    fn clone(&self) -> Self {
127        BitSet {
128            bit_vec: self.bit_vec.clone(),
129        }
130    }
131
132    fn clone_from(&mut self, other: &Self) {
133        self.bit_vec.clone_from(&other.bit_vec);
134    }
135}
136
137impl<B: BitBlock> Default for BitSet<B> {
138    #[inline]
139    fn default() -> Self {
140        BitSet {
141            bit_vec: Default::default(),
142        }
143    }
144}
145
146impl<B: BitBlock> FromIterator<usize> for BitSet<B> {
147    fn from_iter<I: IntoIterator<Item = usize>>(iter: I) -> Self {
148        let mut ret = Self::default();
149        ret.extend(iter);
150        ret
151    }
152}
153
154impl<B: BitBlock> Extend<usize> for BitSet<B> {
155    #[inline]
156    fn extend<I: IntoIterator<Item = usize>>(&mut self, iter: I) {
157        for i in iter {
158            self.insert(i);
159        }
160    }
161}
162
163impl<B: BitBlock> PartialOrd for BitSet<B> {
164    #[inline]
165    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
166        Some(self.cmp(other))
167    }
168}
169
170impl<B: BitBlock> Ord for BitSet<B> {
171    #[inline]
172    fn cmp(&self, other: &Self) -> Ordering {
173        self.iter().cmp(other)
174    }
175}
176
177impl<B: BitBlock> PartialEq for BitSet<B> {
178    #[inline]
179    fn eq(&self, other: &Self) -> bool {
180        self.iter().eq(other)
181    }
182}
183
184impl<B: BitBlock> Eq for BitSet<B> {}
185
186impl BitSet<u32> {
187    /// Creates a new empty `BitSet`.
188    ///
189    /// # Examples
190    ///
191    /// ```
192    /// use bit_set::BitSet;
193    ///
194    /// let mut s = BitSet::new();
195    /// ```
196    #[inline]
197    pub fn new() -> Self {
198        Self::default()
199    }
200
201    /// Creates a new `BitSet` with initially no contents, able to
202    /// hold `nbits` elements without resizing.
203    ///
204    /// # Examples
205    ///
206    /// ```
207    /// use bit_set::BitSet;
208    ///
209    /// let mut s = BitSet::with_capacity(100);
210    /// assert!(s.capacity() >= 100);
211    /// ```
212    #[inline]
213    pub fn with_capacity(nbits: usize) -> Self {
214        let bit_vec = BitVec::from_elem(nbits, false);
215        Self::from_bit_vec(bit_vec)
216    }
217
218    /// Creates a new `BitSet` from the given bit vector.
219    ///
220    /// # Examples
221    ///
222    /// ```
223    /// extern crate bit_vec;
224    /// extern crate bit_set;
225    ///
226    /// fn main() {
227    ///     use bit_vec::BitVec;
228    ///     use bit_set::BitSet;
229    ///
230    ///     let bv = BitVec::from_bytes(&[0b01100000]);
231    ///     let s = BitSet::from_bit_vec(bv);
232    ///
233    ///     // Print 1, 2 in arbitrary order
234    ///     for x in s.iter() {
235    ///         println!("{}", x);
236    ///     }
237    /// }
238    /// ```
239    #[inline]
240    pub fn from_bit_vec(bit_vec: BitVec) -> Self {
241        BitSet { bit_vec }
242    }
243
244    pub fn from_bytes(bytes: &[u8]) -> Self {
245        BitSet {
246            bit_vec: BitVec::from_bytes(bytes),
247        }
248    }
249}
250
251impl<B: BitBlock> BitSet<B> {
252    /// Returns the capacity in bits for this bit vector. Inserting any
253    /// element less than this amount will not trigger a resizing.
254    ///
255    /// # Examples
256    ///
257    /// ```
258    /// use bit_set::BitSet;
259    ///
260    /// let mut s = BitSet::with_capacity(100);
261    /// assert!(s.capacity() >= 100);
262    /// ```
263    #[inline]
264    pub fn capacity(&self) -> usize {
265        self.bit_vec.capacity()
266    }
267
268    /// Reserves capacity for the given `BitSet` to contain `len` distinct elements. In the case
269    /// of `BitSet` this means reallocations will not occur as long as all inserted elements
270    /// are less than `len`.
271    ///
272    /// The collection may reserve more space to avoid frequent reallocations.
273    ///
274    ///
275    /// # Examples
276    ///
277    /// ```
278    /// use bit_set::BitSet;
279    ///
280    /// let mut s = BitSet::new();
281    /// s.reserve_len(10);
282    /// assert!(s.capacity() >= 10);
283    /// ```
284    pub fn reserve_len(&mut self, len: usize) {
285        let cur_len = self.bit_vec.len();
286        if len >= cur_len {
287            self.bit_vec.reserve(len - cur_len);
288        }
289    }
290
291    /// Reserves the minimum capacity for the given `BitSet` to contain `len` distinct elements.
292    /// In the case of `BitSet` this means reallocations will not occur as long as all inserted
293    /// elements are less than `len`.
294    ///
295    /// Note that the allocator may give the collection more space than it requests. Therefore
296    /// capacity can not be relied upon to be precisely minimal. Prefer `reserve_len` if future
297    /// insertions are expected.
298    ///
299    ///
300    /// # Examples
301    ///
302    /// ```
303    /// use bit_set::BitSet;
304    ///
305    /// let mut s = BitSet::new();
306    /// s.reserve_len_exact(10);
307    /// assert!(s.capacity() >= 10);
308    /// ```
309    pub fn reserve_len_exact(&mut self, len: usize) {
310        let cur_len = self.bit_vec.len();
311        if len >= cur_len {
312            self.bit_vec.reserve_exact(len - cur_len);
313        }
314    }
315
316    /// Consumes this set to return the underlying bit vector.
317    ///
318    /// # Examples
319    ///
320    /// ```
321    /// use bit_set::BitSet;
322    ///
323    /// let mut s = BitSet::new();
324    /// s.insert(0);
325    /// s.insert(3);
326    ///
327    /// let bv = s.into_bit_vec();
328    /// assert!(bv[0]);
329    /// assert!(bv[3]);
330    /// ```
331    #[inline]
332    pub fn into_bit_vec(self) -> BitVec<B> {
333        self.bit_vec
334    }
335
336    /// Returns a reference to the underlying bit vector.
337    ///
338    /// # Examples
339    ///
340    /// ```
341    /// use bit_set::BitSet;
342    ///
343    /// let mut set = BitSet::new();
344    /// set.insert(0);
345    ///
346    /// let bv = set.get_ref();
347    /// assert_eq!(bv[0], true);
348    /// ```
349    #[inline]
350    pub fn get_ref(&self) -> &BitVec<B> {
351        &self.bit_vec
352    }
353
354    /// Returns a mutable reference to the underlying bit vector.
355    ///
356    /// # Examples
357    ///
358    /// ```
359    /// use bit_set::BitSet;
360    ///
361    /// let mut set = BitSet::new();
362    /// set.insert(0);
363    /// set.insert(3);
364    ///
365    /// {
366    ///     let bv = set.get_mut();
367    ///     bv.set(1, true);
368    /// }
369    ///
370    /// assert!(set.contains(0));
371    /// assert!(set.contains(1));
372    /// assert!(set.contains(3));
373    /// ```
374    #[inline]
375    pub fn get_mut(&mut self) -> &mut BitVec<B> {
376        &mut self.bit_vec
377    }
378
379    #[inline]
380    fn other_op<F>(&mut self, other: &Self, mut f: F)
381    where
382        F: FnMut(B, B) -> B,
383    {
384        // Unwrap BitVecs
385        let self_bit_vec = &mut self.bit_vec;
386        let other_bit_vec = &other.bit_vec;
387
388        let self_len = self_bit_vec.len();
389        let other_len = other_bit_vec.len();
390
391        // Expand the vector if necessary
392        if self_len < other_len {
393            self_bit_vec.grow(other_len - self_len, false);
394        }
395
396        // virtually pad other with 0's for equal lengths
397        let other_words = {
398            let (_, result) = match_words(self_bit_vec, other_bit_vec);
399            result
400        };
401
402        // Apply values found in other
403        for (i, w) in other_words {
404            let old = self_bit_vec.storage()[i];
405            let new = f(old, w);
406            unsafe {
407                self_bit_vec.storage_mut()[i] = new;
408            }
409        }
410    }
411
412    /// Truncates the underlying vector to the least length required.
413    ///
414    /// # Examples
415    ///
416    /// ```
417    /// use bit_set::BitSet;
418    ///
419    /// let mut s = BitSet::new();
420    /// s.insert(3231);
421    /// s.remove(3231);
422    ///
423    /// // Internal storage will probably be bigger than necessary
424    /// println!("old capacity: {}", s.capacity());
425    /// assert!(s.capacity() >= 3231);
426    ///
427    /// // Now should be smaller
428    /// s.shrink_to_fit();
429    /// println!("new capacity: {}", s.capacity());
430    /// ```
431    #[inline]
432    pub fn shrink_to_fit(&mut self) {
433        let bit_vec = &mut self.bit_vec;
434        // Obtain original length
435        let old_len = bit_vec.storage().len();
436        // Obtain coarse trailing zero length
437        let n = bit_vec
438            .storage()
439            .iter()
440            .rev()
441            .take_while(|&&n| n == B::zero())
442            .count();
443        // Truncate away all empty trailing blocks, then shrink_to_fit
444        let trunc_len = old_len - n;
445        unsafe {
446            bit_vec.storage_mut().truncate(trunc_len);
447            bit_vec.set_len(trunc_len * B::bits());
448        }
449        bit_vec.shrink_to_fit();
450    }
451
452    /// Iterator over each usize stored in the `BitSet`.
453    ///
454    /// # Examples
455    ///
456    /// ```
457    /// use bit_set::BitSet;
458    ///
459    /// let s = BitSet::from_bytes(&[0b01001010]);
460    ///
461    /// // Print 1, 4, 6 in arbitrary order
462    /// for x in s.iter() {
463    ///     println!("{}", x);
464    /// }
465    /// ```
466    #[inline]
467    pub fn iter(&self) -> Iter<B> {
468        Iter(BlockIter::from_blocks(self.bit_vec.blocks()))
469    }
470
471    /// Iterator over each usize stored in `self` union `other`.
472    /// See [`union_with`] for an efficient in-place version.
473    ///
474    /// # Examples
475    ///
476    /// ```
477    /// use bit_set::BitSet;
478    ///
479    /// let a = BitSet::from_bytes(&[0b01101000]);
480    /// let b = BitSet::from_bytes(&[0b10100000]);
481    ///
482    /// // Print 0, 1, 2, 4 in arbitrary order
483    /// for x in a.union(&b) {
484    ///     println!("{}", x);
485    /// }
486    /// ```
487    ///
488    /// [`union_with`]: Self::union_with
489    #[inline]
490    pub fn union<'a>(&'a self, other: &'a Self) -> Union<'a, B> {
491        fn or<B: BitBlock>(w1: B, w2: B) -> B {
492            w1 | w2
493        }
494
495        Union(BlockIter::from_blocks(TwoBitPositions {
496            set: self.bit_vec.blocks(),
497            other: other.bit_vec.blocks(),
498            merge: or,
499        }))
500    }
501
502    /// Iterator over each usize stored in `self` intersect `other`.
503    /// See [`intersect_with`] for an efficient in-place version.
504    ///
505    /// # Examples
506    ///
507    /// ```
508    /// use bit_set::BitSet;
509    ///
510    /// let a = BitSet::from_bytes(&[0b01101000]);
511    /// let b = BitSet::from_bytes(&[0b10100000]);
512    ///
513    /// // Print 2
514    /// for x in a.intersection(&b) {
515    ///     println!("{}", x);
516    /// }
517    /// ```
518    ///
519    /// [`intersect_with`]: Self::intersect_with
520    #[inline]
521    pub fn intersection<'a>(&'a self, other: &'a Self) -> Intersection<'a, B> {
522        fn bitand<B: BitBlock>(w1: B, w2: B) -> B {
523            w1 & w2
524        }
525        let min = cmp::min(self.bit_vec.len(), other.bit_vec.len());
526
527        Intersection {
528            iter: BlockIter::from_blocks(TwoBitPositions {
529                set: self.bit_vec.blocks(),
530                other: other.bit_vec.blocks(),
531                merge: bitand,
532            }),
533            n: min,
534        }
535    }
536
537    /// Iterator over each usize stored in the `self` setminus `other`.
538    /// See [`difference_with`] for an efficient in-place version.
539    ///
540    /// # Examples
541    ///
542    /// ```
543    /// use bit_set::BitSet;
544    ///
545    /// let a = BitSet::from_bytes(&[0b01101000]);
546    /// let b = BitSet::from_bytes(&[0b10100000]);
547    ///
548    /// // Print 1, 4 in arbitrary order
549    /// for x in a.difference(&b) {
550    ///     println!("{}", x);
551    /// }
552    ///
553    /// // Note that difference is not symmetric,
554    /// // and `b - a` means something else.
555    /// // This prints 0
556    /// for x in b.difference(&a) {
557    ///     println!("{}", x);
558    /// }
559    /// ```
560    ///
561    /// [`difference_with`]: Self::difference_with
562    #[inline]
563    pub fn difference<'a>(&'a self, other: &'a Self) -> Difference<'a, B> {
564        fn diff<B: BitBlock>(w1: B, w2: B) -> B {
565            w1 & !w2
566        }
567
568        Difference(BlockIter::from_blocks(TwoBitPositions {
569            set: self.bit_vec.blocks(),
570            other: other.bit_vec.blocks(),
571            merge: diff,
572        }))
573    }
574
575    /// Iterator over each usize stored in the symmetric difference of `self` and `other`.
576    /// See [`symmetric_difference_with`] for an efficient in-place version.
577    ///
578    /// # Examples
579    ///
580    /// ```
581    /// use bit_set::BitSet;
582    ///
583    /// let a = BitSet::from_bytes(&[0b01101000]);
584    /// let b = BitSet::from_bytes(&[0b10100000]);
585    ///
586    /// // Print 0, 1, 4 in arbitrary order
587    /// for x in a.symmetric_difference(&b) {
588    ///     println!("{}", x);
589    /// }
590    /// ```
591    ///
592    /// [`symmetric_difference_with`]: Self::symmetric_difference_with
593    #[inline]
594    pub fn symmetric_difference<'a>(&'a self, other: &'a Self) -> SymmetricDifference<'a, B> {
595        fn bitxor<B: BitBlock>(w1: B, w2: B) -> B {
596            w1 ^ w2
597        }
598
599        SymmetricDifference(BlockIter::from_blocks(TwoBitPositions {
600            set: self.bit_vec.blocks(),
601            other: other.bit_vec.blocks(),
602            merge: bitxor,
603        }))
604    }
605
606    /// Unions in-place with the specified other bit vector.
607    ///
608    /// # Examples
609    ///
610    /// ```
611    /// use bit_set::BitSet;
612    ///
613    /// let a   = 0b01101000;
614    /// let b   = 0b10100000;
615    /// let res = 0b11101000;
616    ///
617    /// let mut a = BitSet::from_bytes(&[a]);
618    /// let b = BitSet::from_bytes(&[b]);
619    /// let res = BitSet::from_bytes(&[res]);
620    ///
621    /// a.union_with(&b);
622    /// assert_eq!(a, res);
623    /// ```
624    #[inline]
625    pub fn union_with(&mut self, other: &Self) {
626        self.other_op(other, |w1, w2| w1 | w2);
627    }
628
629    /// Intersects in-place with the specified other bit vector.
630    ///
631    /// # Examples
632    ///
633    /// ```
634    /// use bit_set::BitSet;
635    ///
636    /// let a   = 0b01101000;
637    /// let b   = 0b10100000;
638    /// let res = 0b00100000;
639    ///
640    /// let mut a = BitSet::from_bytes(&[a]);
641    /// let b = BitSet::from_bytes(&[b]);
642    /// let res = BitSet::from_bytes(&[res]);
643    ///
644    /// a.intersect_with(&b);
645    /// assert_eq!(a, res);
646    /// ```
647    #[inline]
648    pub fn intersect_with(&mut self, other: &Self) {
649        self.other_op(other, |w1, w2| w1 & w2);
650    }
651
652    /// Makes this bit vector the difference with the specified other bit vector
653    /// in-place.
654    ///
655    /// # Examples
656    ///
657    /// ```
658    /// use bit_set::BitSet;
659    ///
660    /// let a   = 0b01101000;
661    /// let b   = 0b10100000;
662    /// let a_b = 0b01001000; // a - b
663    /// let b_a = 0b10000000; // b - a
664    ///
665    /// let mut bva = BitSet::from_bytes(&[a]);
666    /// let bvb = BitSet::from_bytes(&[b]);
667    /// let bva_b = BitSet::from_bytes(&[a_b]);
668    /// let bvb_a = BitSet::from_bytes(&[b_a]);
669    ///
670    /// bva.difference_with(&bvb);
671    /// assert_eq!(bva, bva_b);
672    ///
673    /// let bva = BitSet::from_bytes(&[a]);
674    /// let mut bvb = BitSet::from_bytes(&[b]);
675    ///
676    /// bvb.difference_with(&bva);
677    /// assert_eq!(bvb, bvb_a);
678    /// ```
679    #[inline]
680    pub fn difference_with(&mut self, other: &Self) {
681        self.other_op(other, |w1, w2| w1 & !w2);
682    }
683
684    /// Makes this bit vector the symmetric difference with the specified other
685    /// bit vector in-place.
686    ///
687    /// # Examples
688    ///
689    /// ```
690    /// use bit_set::BitSet;
691    ///
692    /// let a   = 0b01101000;
693    /// let b   = 0b10100000;
694    /// let res = 0b11001000;
695    ///
696    /// let mut a = BitSet::from_bytes(&[a]);
697    /// let b = BitSet::from_bytes(&[b]);
698    /// let res = BitSet::from_bytes(&[res]);
699    ///
700    /// a.symmetric_difference_with(&b);
701    /// assert_eq!(a, res);
702    /// ```
703    #[inline]
704    pub fn symmetric_difference_with(&mut self, other: &Self) {
705        self.other_op(other, |w1, w2| w1 ^ w2);
706    }
707
708    /*
709        /// Moves all elements from `other` into `Self`, leaving `other` empty.
710        ///
711        /// # Examples
712        ///
713        /// ```
714        /// use bit_set::BitSet;
715        ///
716        /// let mut a = BitSet::new();
717        /// a.insert(2);
718        /// a.insert(6);
719        ///
720        /// let mut b = BitSet::new();
721        /// b.insert(1);
722        /// b.insert(3);
723        /// b.insert(6);
724        ///
725        /// a.append(&mut b);
726        ///
727        /// assert_eq!(a.len(), 4);
728        /// assert_eq!(b.len(), 0);
729        /// assert_eq!(a, BitSet::from_bytes(&[0b01110010]));
730        /// ```
731        pub fn append(&mut self, other: &mut Self) {
732            self.union_with(other);
733            other.clear();
734        }
735
736        /// Splits the `BitSet` into two at the given key including the key.
737        /// Retains the first part in-place while returning the second part.
738        ///
739        /// # Examples
740        ///
741        /// ```
742        /// use bit_set::BitSet;
743        ///
744        /// let mut a = BitSet::new();
745        /// a.insert(2);
746        /// a.insert(6);
747        /// a.insert(1);
748        /// a.insert(3);
749        ///
750        /// let b = a.split_off(3);
751        ///
752        /// assert_eq!(a.len(), 2);
753        /// assert_eq!(b.len(), 2);
754        /// assert_eq!(a, BitSet::from_bytes(&[0b01100000]));
755        /// assert_eq!(b, BitSet::from_bytes(&[0b00010010]));
756        /// ```
757        pub fn split_off(&mut self, at: usize) -> Self {
758            let mut other = BitSet::new();
759
760            if at == 0 {
761                swap(self, &mut other);
762                return other;
763            } else if at >= self.bit_vec.len() {
764                return other;
765            }
766
767            // Calculate block and bit at which to split
768            let w = at / BITS;
769            let b = at % BITS;
770
771            // Pad `other` with `w` zero blocks,
772            // append `self`'s blocks in the range from `w` to the end to `other`
773            other.bit_vec.storage_mut().extend(repeat(0u32).take(w)
774                                         .chain(self.bit_vec.storage()[w..].iter().cloned()));
775            other.bit_vec.nbits = self.bit_vec.nbits;
776
777            if b > 0 {
778                other.bit_vec.storage_mut()[w] &= !0 << b;
779            }
780
781            // Sets `bit_vec.len()` and fixes the last block as well
782            self.bit_vec.truncate(at);
783
784            other
785        }
786    */
787
788    /// Returns the number of set bits in this set.
789    #[inline]
790    pub fn len(&self) -> usize {
791        self.bit_vec.blocks().fold(0, |acc, n| acc + n.count_ones())
792    }
793
794    /// Returns whether there are no bits set in this set
795    #[inline]
796    pub fn is_empty(&self) -> bool {
797        self.bit_vec.none()
798    }
799
800    /// Clears all bits in this set
801    #[inline]
802    pub fn clear(&mut self) {
803        self.bit_vec.clear();
804    }
805
806    /// Returns `true` if this set contains the specified integer.
807    #[inline]
808    pub fn contains(&self, value: usize) -> bool {
809        let bit_vec = &self.bit_vec;
810        value < bit_vec.len() && bit_vec[value]
811    }
812
813    /// Returns `true` if the set has no elements in common with `other`.
814    /// This is equivalent to checking for an empty intersection.
815    #[inline]
816    pub fn is_disjoint(&self, other: &Self) -> bool {
817        self.intersection(other).next().is_none()
818    }
819
820    /// Returns `true` if the set is a subset of another.
821    #[inline]
822    pub fn is_subset(&self, other: &Self) -> bool {
823        let self_bit_vec = &self.bit_vec;
824        let other_bit_vec = &other.bit_vec;
825        let other_blocks = blocks_for_bits::<B>(other_bit_vec.len());
826
827        // Check that `self` intersect `other` is self
828        self_bit_vec.blocks().zip(other_bit_vec.blocks()).all(|(w1, w2)| w1 & w2 == w1) &&
829        // Make sure if `self` has any more blocks than `other`, they're all 0
830        self_bit_vec.blocks().skip(other_blocks).all(|w| w == B::zero())
831    }
832
833    /// Returns `true` if the set is a superset of another.
834    #[inline]
835    pub fn is_superset(&self, other: &Self) -> bool {
836        other.is_subset(self)
837    }
838
839    /// Adds a value to the set. Returns `true` if the value was not already
840    /// present in the set.
841    pub fn insert(&mut self, value: usize) -> bool {
842        if self.contains(value) {
843            return false;
844        }
845
846        // Ensure we have enough space to hold the new element
847        let len = self.bit_vec.len();
848        if value >= len {
849            self.bit_vec.grow(value - len + 1, false);
850        }
851
852        self.bit_vec.set(value, true);
853        true
854    }
855
856    /// Removes a value from the set. Returns `true` if the value was
857    /// present in the set.
858    pub fn remove(&mut self, value: usize) -> bool {
859        if !self.contains(value) {
860            return false;
861        }
862
863        self.bit_vec.set(value, false);
864
865        true
866    }
867
868    /// Excludes `element` and all greater elements from the `BitSet`.
869    pub fn truncate(&mut self, element: usize) {
870        self.bit_vec.truncate(element);
871    }
872}
873
874impl<B: BitBlock> fmt::Debug for BitSet<B> {
875    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
876        fmt.debug_set().entries(self).finish()
877    }
878}
879
880impl<B: BitBlock> hash::Hash for BitSet<B> {
881    fn hash<H: hash::Hasher>(&self, state: &mut H) {
882        for pos in self {
883            pos.hash(state);
884        }
885    }
886}
887
888#[derive(Clone)]
889struct BlockIter<T, B> {
890    head: B,
891    head_offset: usize,
892    tail: T,
893}
894
895impl<T, B: BitBlock> BlockIter<T, B>
896where
897    T: Iterator<Item = B>,
898{
899    fn from_blocks(mut blocks: T) -> BlockIter<T, B> {
900        let h = blocks.next().unwrap_or_else(B::zero);
901        BlockIter {
902            tail: blocks,
903            head: h,
904            head_offset: 0,
905        }
906    }
907}
908
909/// An iterator combining two `BitSet` iterators.
910#[derive(Clone)]
911struct TwoBitPositions<'a, B: 'a> {
912    set: Blocks<'a, B>,
913    other: Blocks<'a, B>,
914    merge: fn(B, B) -> B,
915}
916
917/// An iterator for `BitSet`.
918#[derive(Clone)]
919pub struct Iter<'a, B: 'a>(BlockIter<Blocks<'a, B>, B>);
920#[derive(Clone)]
921pub struct Union<'a, B: 'a>(BlockIter<TwoBitPositions<'a, B>, B>);
922#[derive(Clone)]
923pub struct Intersection<'a, B: 'a> {
924    iter: BlockIter<TwoBitPositions<'a, B>, B>,
925    // as an optimization, we compute the maximum possible
926    // number of elements in the intersection, and count it
927    // down as we return elements. If we reach zero, we can
928    // stop.
929    n: usize,
930}
931#[derive(Clone)]
932pub struct Difference<'a, B: 'a>(BlockIter<TwoBitPositions<'a, B>, B>);
933#[derive(Clone)]
934pub struct SymmetricDifference<'a, B: 'a>(BlockIter<TwoBitPositions<'a, B>, B>);
935
936impl<T, B: BitBlock> Iterator for BlockIter<T, B>
937where
938    T: Iterator<Item = B>,
939{
940    type Item = usize;
941
942    fn next(&mut self) -> Option<usize> {
943        while self.head == B::zero() {
944            match self.tail.next() {
945                Some(w) => self.head = w,
946                None => return None,
947            }
948            self.head_offset += B::bits();
949        }
950
951        // from the current block, isolate the
952        // LSB and subtract 1, producing k:
953        // a block with a number of set bits
954        // equal to the index of the LSB
955        let k = (self.head & (!self.head + B::one())) - B::one();
956        // update block, removing the LSB
957        self.head = self.head & (self.head - B::one());
958        // return offset + (index of LSB)
959        Some(self.head_offset + (B::count_ones(k)))
960    }
961
962    fn count(self) -> usize {
963        self.head.count_ones() + self.tail.map(|block| block.count_ones()).sum::<usize>()
964    }
965
966    #[inline]
967    fn size_hint(&self) -> (usize, Option<usize>) {
968        match self.tail.size_hint() {
969            (_, Some(h)) => (0, Some((1 + h) * B::bits())),
970            _ => (0, None),
971        }
972    }
973}
974
975impl<'a, B: BitBlock> Iterator for TwoBitPositions<'a, B> {
976    type Item = B;
977
978    fn next(&mut self) -> Option<B> {
979        match (self.set.next(), self.other.next()) {
980            (Some(a), Some(b)) => Some((self.merge)(a, b)),
981            (Some(a), None) => Some((self.merge)(a, B::zero())),
982            (None, Some(b)) => Some((self.merge)(B::zero(), b)),
983            _ => None,
984        }
985    }
986
987    #[inline]
988    fn size_hint(&self) -> (usize, Option<usize>) {
989        let (a, au) = self.set.size_hint();
990        let (b, bu) = self.other.size_hint();
991
992        let upper = match (au, bu) {
993            (Some(au), Some(bu)) => Some(cmp::max(au, bu)),
994            _ => None,
995        };
996
997        (cmp::max(a, b), upper)
998    }
999}
1000
1001impl<'a, B: BitBlock> Iterator for Iter<'a, B> {
1002    type Item = usize;
1003
1004    #[inline]
1005    fn next(&mut self) -> Option<usize> {
1006        self.0.next()
1007    }
1008    #[inline]
1009    fn size_hint(&self) -> (usize, Option<usize>) {
1010        self.0.size_hint()
1011    }
1012    #[inline]
1013    fn count(self) -> usize {
1014        self.0.count()
1015    }
1016}
1017
1018impl<'a, B: BitBlock> Iterator for Union<'a, B> {
1019    type Item = usize;
1020
1021    #[inline]
1022    fn next(&mut self) -> Option<usize> {
1023        self.0.next()
1024    }
1025    #[inline]
1026    fn size_hint(&self) -> (usize, Option<usize>) {
1027        self.0.size_hint()
1028    }
1029    #[inline]
1030    fn count(self) -> usize {
1031        self.0.count()
1032    }
1033}
1034
1035impl<'a, B: BitBlock> Iterator for Intersection<'a, B> {
1036    type Item = usize;
1037
1038    #[inline]
1039    fn next(&mut self) -> Option<usize> {
1040        if self.n != 0 {
1041            self.n -= 1;
1042            self.iter.next()
1043        } else {
1044            None
1045        }
1046    }
1047    #[inline]
1048    fn size_hint(&self) -> (usize, Option<usize>) {
1049        // We could invoke self.iter.size_hint() and incorporate that into the hint.
1050        // In practice, that does not seem worthwhile because the lower bound will
1051        // always be zero and the upper bound could only possibly less then n in a
1052        // partially iterated iterator. However, it makes little sense ask for size_hint
1053        // in a partially iterated iterator, so it did not seem worthwhile.
1054        (0, Some(self.n))
1055    }
1056    #[inline]
1057    fn count(self) -> usize {
1058        self.iter.count()
1059    }
1060}
1061
1062impl<'a, B: BitBlock> Iterator for Difference<'a, B> {
1063    type Item = usize;
1064
1065    #[inline]
1066    fn next(&mut self) -> Option<usize> {
1067        self.0.next()
1068    }
1069    #[inline]
1070    fn size_hint(&self) -> (usize, Option<usize>) {
1071        self.0.size_hint()
1072    }
1073    #[inline]
1074    fn count(self) -> usize {
1075        self.0.count()
1076    }
1077}
1078
1079impl<'a, B: BitBlock> Iterator for SymmetricDifference<'a, B> {
1080    type Item = usize;
1081
1082    #[inline]
1083    fn next(&mut self) -> Option<usize> {
1084        self.0.next()
1085    }
1086    #[inline]
1087    fn size_hint(&self) -> (usize, Option<usize>) {
1088        self.0.size_hint()
1089    }
1090    #[inline]
1091    fn count(self) -> usize {
1092        self.0.count()
1093    }
1094}
1095
1096impl<'a, B: BitBlock> IntoIterator for &'a BitSet<B> {
1097    type Item = usize;
1098    type IntoIter = Iter<'a, B>;
1099
1100    fn into_iter(self) -> Iter<'a, B> {
1101        self.iter()
1102    }
1103}
1104
1105#[cfg(test)]
1106mod tests {
1107    use super::BitSet;
1108    use bit_vec::BitVec;
1109    use std::cmp::Ordering::{Equal, Greater, Less};
1110    use std::vec::Vec;
1111    use std::{format, vec};
1112
1113    #[test]
1114    fn test_bit_set_show() {
1115        let mut s = BitSet::new();
1116        s.insert(1);
1117        s.insert(10);
1118        s.insert(50);
1119        s.insert(2);
1120        assert_eq!("{1, 2, 10, 50}", format!("{:?}", s));
1121    }
1122
1123    #[test]
1124    fn test_bit_set_from_usizes() {
1125        let usizes = vec![0, 2, 2, 3];
1126        let a: BitSet = usizes.into_iter().collect();
1127        let mut b = BitSet::new();
1128        b.insert(0);
1129        b.insert(2);
1130        b.insert(3);
1131        assert_eq!(a, b);
1132    }
1133
1134    #[test]
1135    fn test_bit_set_iterator() {
1136        let usizes = vec![0, 2, 2, 3];
1137        let bit_vec: BitSet = usizes.into_iter().collect();
1138
1139        let idxs: Vec<_> = bit_vec.iter().collect();
1140        assert_eq!(idxs, [0, 2, 3]);
1141        assert_eq!(bit_vec.iter().count(), 3);
1142
1143        let long: BitSet = (0..10000).filter(|&n| n % 2 == 0).collect();
1144        let real: Vec<_> = (0..10000 / 2).map(|x| x * 2).collect();
1145
1146        let idxs: Vec<_> = long.iter().collect();
1147        assert_eq!(idxs, real);
1148        assert_eq!(long.iter().count(), real.len());
1149    }
1150
1151    #[test]
1152    fn test_bit_set_frombit_vec_init() {
1153        let bools = [true, false];
1154        let lengths = [10, 64, 100];
1155        for &b in &bools {
1156            for &l in &lengths {
1157                let bitset = BitSet::from_bit_vec(BitVec::from_elem(l, b));
1158                assert_eq!(bitset.contains(1), b);
1159                assert_eq!(bitset.contains(l - 1), b);
1160                assert!(!bitset.contains(l));
1161            }
1162        }
1163    }
1164
1165    #[test]
1166    fn test_bit_vec_masking() {
1167        let b = BitVec::from_elem(140, true);
1168        let mut bs = BitSet::from_bit_vec(b);
1169        assert!(bs.contains(139));
1170        assert!(!bs.contains(140));
1171        assert!(bs.insert(150));
1172        assert!(!bs.contains(140));
1173        assert!(!bs.contains(149));
1174        assert!(bs.contains(150));
1175        assert!(!bs.contains(151));
1176    }
1177
1178    #[test]
1179    fn test_bit_set_basic() {
1180        let mut b = BitSet::new();
1181        assert!(b.insert(3));
1182        assert!(!b.insert(3));
1183        assert!(b.contains(3));
1184        assert!(b.insert(4));
1185        assert!(!b.insert(4));
1186        assert!(b.contains(3));
1187        assert!(b.insert(400));
1188        assert!(!b.insert(400));
1189        assert!(b.contains(400));
1190        assert_eq!(b.len(), 3);
1191    }
1192
1193    #[test]
1194    fn test_bit_set_intersection() {
1195        let mut a = BitSet::new();
1196        let mut b = BitSet::new();
1197
1198        assert!(a.insert(11));
1199        assert!(a.insert(1));
1200        assert!(a.insert(3));
1201        assert!(a.insert(77));
1202        assert!(a.insert(103));
1203        assert!(a.insert(5));
1204
1205        assert!(b.insert(2));
1206        assert!(b.insert(11));
1207        assert!(b.insert(77));
1208        assert!(b.insert(5));
1209        assert!(b.insert(3));
1210
1211        let expected = [3, 5, 11, 77];
1212        let actual: Vec<_> = a.intersection(&b).collect();
1213        assert_eq!(actual, expected);
1214        assert_eq!(a.intersection(&b).count(), expected.len());
1215    }
1216
1217    #[test]
1218    fn test_bit_set_difference() {
1219        let mut a = BitSet::new();
1220        let mut b = BitSet::new();
1221
1222        assert!(a.insert(1));
1223        assert!(a.insert(3));
1224        assert!(a.insert(5));
1225        assert!(a.insert(200));
1226        assert!(a.insert(500));
1227
1228        assert!(b.insert(3));
1229        assert!(b.insert(200));
1230
1231        let expected = [1, 5, 500];
1232        let actual: Vec<_> = a.difference(&b).collect();
1233        assert_eq!(actual, expected);
1234        assert_eq!(a.difference(&b).count(), expected.len());
1235    }
1236
1237    #[test]
1238    fn test_bit_set_symmetric_difference() {
1239        let mut a = BitSet::new();
1240        let mut b = BitSet::new();
1241
1242        assert!(a.insert(1));
1243        assert!(a.insert(3));
1244        assert!(a.insert(5));
1245        assert!(a.insert(9));
1246        assert!(a.insert(11));
1247
1248        assert!(b.insert(3));
1249        assert!(b.insert(9));
1250        assert!(b.insert(14));
1251        assert!(b.insert(220));
1252
1253        let expected = [1, 5, 11, 14, 220];
1254        let actual: Vec<_> = a.symmetric_difference(&b).collect();
1255        assert_eq!(actual, expected);
1256        assert_eq!(a.symmetric_difference(&b).count(), expected.len());
1257    }
1258
1259    #[test]
1260    fn test_bit_set_union() {
1261        let mut a = BitSet::new();
1262        let mut b = BitSet::new();
1263        assert!(a.insert(1));
1264        assert!(a.insert(3));
1265        assert!(a.insert(5));
1266        assert!(a.insert(9));
1267        assert!(a.insert(11));
1268        assert!(a.insert(160));
1269        assert!(a.insert(19));
1270        assert!(a.insert(24));
1271        assert!(a.insert(200));
1272
1273        assert!(b.insert(1));
1274        assert!(b.insert(5));
1275        assert!(b.insert(9));
1276        assert!(b.insert(13));
1277        assert!(b.insert(19));
1278
1279        let expected = [1, 3, 5, 9, 11, 13, 19, 24, 160, 200];
1280        let actual: Vec<_> = a.union(&b).collect();
1281        assert_eq!(actual, expected);
1282        assert_eq!(a.union(&b).count(), expected.len());
1283    }
1284
1285    #[test]
1286    fn test_bit_set_subset() {
1287        let mut set1 = BitSet::new();
1288        let mut set2 = BitSet::new();
1289
1290        assert!(set1.is_subset(&set2)); //  {}  {}
1291        set2.insert(100);
1292        assert!(set1.is_subset(&set2)); //  {}  { 1 }
1293        set2.insert(200);
1294        assert!(set1.is_subset(&set2)); //  {}  { 1, 2 }
1295        set1.insert(200);
1296        assert!(set1.is_subset(&set2)); //  { 2 }  { 1, 2 }
1297        set1.insert(300);
1298        assert!(!set1.is_subset(&set2)); // { 2, 3 }  { 1, 2 }
1299        set2.insert(300);
1300        assert!(set1.is_subset(&set2)); // { 2, 3 }  { 1, 2, 3 }
1301        set2.insert(400);
1302        assert!(set1.is_subset(&set2)); // { 2, 3 }  { 1, 2, 3, 4 }
1303        set2.remove(100);
1304        assert!(set1.is_subset(&set2)); // { 2, 3 }  { 2, 3, 4 }
1305        set2.remove(300);
1306        assert!(!set1.is_subset(&set2)); // { 2, 3 }  { 2, 4 }
1307        set1.remove(300);
1308        assert!(set1.is_subset(&set2)); // { 2 }  { 2, 4 }
1309    }
1310
1311    #[test]
1312    fn test_bit_set_is_disjoint() {
1313        let a = BitSet::from_bytes(&[0b10100010]);
1314        let b = BitSet::from_bytes(&[0b01000000]);
1315        let c = BitSet::new();
1316        let d = BitSet::from_bytes(&[0b00110000]);
1317
1318        assert!(!a.is_disjoint(&d));
1319        assert!(!d.is_disjoint(&a));
1320
1321        assert!(a.is_disjoint(&b));
1322        assert!(a.is_disjoint(&c));
1323        assert!(b.is_disjoint(&a));
1324        assert!(b.is_disjoint(&c));
1325        assert!(c.is_disjoint(&a));
1326        assert!(c.is_disjoint(&b));
1327    }
1328
1329    #[test]
1330    fn test_bit_set_union_with() {
1331        //a should grow to include larger elements
1332        let mut a = BitSet::new();
1333        a.insert(0);
1334        let mut b = BitSet::new();
1335        b.insert(5);
1336        let expected = BitSet::from_bytes(&[0b10000100]);
1337        a.union_with(&b);
1338        assert_eq!(a, expected);
1339
1340        // Standard
1341        let mut a = BitSet::from_bytes(&[0b10100010]);
1342        let mut b = BitSet::from_bytes(&[0b01100010]);
1343        let c = a.clone();
1344        a.union_with(&b);
1345        b.union_with(&c);
1346        assert_eq!(a.len(), 4);
1347        assert_eq!(b.len(), 4);
1348    }
1349
1350    #[test]
1351    fn test_bit_set_intersect_with() {
1352        // Explicitly 0'ed bits
1353        let mut a = BitSet::from_bytes(&[0b10100010]);
1354        let mut b = BitSet::from_bytes(&[0b00000000]);
1355        let c = a.clone();
1356        a.intersect_with(&b);
1357        b.intersect_with(&c);
1358        assert!(a.is_empty());
1359        assert!(b.is_empty());
1360
1361        // Uninitialized bits should behave like 0's
1362        let mut a = BitSet::from_bytes(&[0b10100010]);
1363        let mut b = BitSet::new();
1364        let c = a.clone();
1365        a.intersect_with(&b);
1366        b.intersect_with(&c);
1367        assert!(a.is_empty());
1368        assert!(b.is_empty());
1369
1370        // Standard
1371        let mut a = BitSet::from_bytes(&[0b10100010]);
1372        let mut b = BitSet::from_bytes(&[0b01100010]);
1373        let c = a.clone();
1374        a.intersect_with(&b);
1375        b.intersect_with(&c);
1376        assert_eq!(a.len(), 2);
1377        assert_eq!(b.len(), 2);
1378    }
1379
1380    #[test]
1381    fn test_bit_set_difference_with() {
1382        // Explicitly 0'ed bits
1383        let mut a = BitSet::from_bytes(&[0b00000000]);
1384        let b = BitSet::from_bytes(&[0b10100010]);
1385        a.difference_with(&b);
1386        assert!(a.is_empty());
1387
1388        // Uninitialized bits should behave like 0's
1389        let mut a = BitSet::new();
1390        let b = BitSet::from_bytes(&[0b11111111]);
1391        a.difference_with(&b);
1392        assert!(a.is_empty());
1393
1394        // Standard
1395        let mut a = BitSet::from_bytes(&[0b10100010]);
1396        let mut b = BitSet::from_bytes(&[0b01100010]);
1397        let c = a.clone();
1398        a.difference_with(&b);
1399        b.difference_with(&c);
1400        assert_eq!(a.len(), 1);
1401        assert_eq!(b.len(), 1);
1402    }
1403
1404    #[test]
1405    fn test_bit_set_symmetric_difference_with() {
1406        //a should grow to include larger elements
1407        let mut a = BitSet::new();
1408        a.insert(0);
1409        a.insert(1);
1410        let mut b = BitSet::new();
1411        b.insert(1);
1412        b.insert(5);
1413        let expected = BitSet::from_bytes(&[0b10000100]);
1414        a.symmetric_difference_with(&b);
1415        assert_eq!(a, expected);
1416
1417        let mut a = BitSet::from_bytes(&[0b10100010]);
1418        let b = BitSet::new();
1419        let c = a.clone();
1420        a.symmetric_difference_with(&b);
1421        assert_eq!(a, c);
1422
1423        // Standard
1424        let mut a = BitSet::from_bytes(&[0b11100010]);
1425        let mut b = BitSet::from_bytes(&[0b01101010]);
1426        let c = a.clone();
1427        a.symmetric_difference_with(&b);
1428        b.symmetric_difference_with(&c);
1429        assert_eq!(a.len(), 2);
1430        assert_eq!(b.len(), 2);
1431    }
1432
1433    #[test]
1434    fn test_bit_set_eq() {
1435        let a = BitSet::from_bytes(&[0b10100010]);
1436        let b = BitSet::from_bytes(&[0b00000000]);
1437        let c = BitSet::new();
1438
1439        assert!(a == a);
1440        assert!(a != b);
1441        assert!(a != c);
1442        assert!(b == b);
1443        assert!(b == c);
1444        assert!(c == c);
1445    }
1446
1447    #[test]
1448    fn test_bit_set_cmp() {
1449        let a = BitSet::from_bytes(&[0b10100010]);
1450        let b = BitSet::from_bytes(&[0b00000000]);
1451        let c = BitSet::new();
1452
1453        assert_eq!(a.cmp(&b), Greater);
1454        assert_eq!(a.cmp(&c), Greater);
1455        assert_eq!(b.cmp(&a), Less);
1456        assert_eq!(b.cmp(&c), Equal);
1457        assert_eq!(c.cmp(&a), Less);
1458        assert_eq!(c.cmp(&b), Equal);
1459    }
1460
1461    #[test]
1462    fn test_bit_set_shrink_to_fit_new() {
1463        // There was a strange bug where we refused to truncate to 0
1464        // and this would end up actually growing the array in a way
1465        // that (safely corrupted the state).
1466        let mut a = BitSet::new();
1467        assert_eq!(a.len(), 0);
1468        assert_eq!(a.capacity(), 0);
1469        a.shrink_to_fit();
1470        assert_eq!(a.len(), 0);
1471        assert_eq!(a.capacity(), 0);
1472        assert!(!a.contains(1));
1473        a.insert(3);
1474        assert!(a.contains(3));
1475        assert_eq!(a.len(), 1);
1476        assert!(a.capacity() > 0);
1477        a.shrink_to_fit();
1478        assert!(a.contains(3));
1479        assert_eq!(a.len(), 1);
1480        assert!(a.capacity() > 0);
1481    }
1482
1483    #[test]
1484    fn test_bit_set_shrink_to_fit() {
1485        let mut a = BitSet::new();
1486        assert_eq!(a.len(), 0);
1487        assert_eq!(a.capacity(), 0);
1488        a.insert(259);
1489        a.insert(98);
1490        a.insert(3);
1491        assert_eq!(a.len(), 3);
1492        assert!(a.capacity() > 0);
1493        assert!(!a.contains(1));
1494        assert!(a.contains(259));
1495        assert!(a.contains(98));
1496        assert!(a.contains(3));
1497
1498        a.shrink_to_fit();
1499        assert!(!a.contains(1));
1500        assert!(a.contains(259));
1501        assert!(a.contains(98));
1502        assert!(a.contains(3));
1503        assert_eq!(a.len(), 3);
1504        assert!(a.capacity() > 0);
1505
1506        let old_cap = a.capacity();
1507        assert!(a.remove(259));
1508        a.shrink_to_fit();
1509        assert!(a.capacity() < old_cap, "{} {}", a.capacity(), old_cap);
1510        assert!(!a.contains(1));
1511        assert!(!a.contains(259));
1512        assert!(a.contains(98));
1513        assert!(a.contains(3));
1514        assert_eq!(a.len(), 2);
1515
1516        let old_cap2 = a.capacity();
1517        a.clear();
1518        assert_eq!(a.capacity(), old_cap2);
1519        assert_eq!(a.len(), 0);
1520        assert!(!a.contains(1));
1521        assert!(!a.contains(259));
1522        assert!(!a.contains(98));
1523        assert!(!a.contains(3));
1524
1525        a.insert(512);
1526        assert!(a.capacity() > 0);
1527        assert_eq!(a.len(), 1);
1528        assert!(a.contains(512));
1529        assert!(!a.contains(1));
1530        assert!(!a.contains(259));
1531        assert!(!a.contains(98));
1532        assert!(!a.contains(3));
1533
1534        a.remove(512);
1535        a.shrink_to_fit();
1536        assert_eq!(a.capacity(), 0);
1537        assert_eq!(a.len(), 0);
1538        assert!(!a.contains(512));
1539        assert!(!a.contains(1));
1540        assert!(!a.contains(259));
1541        assert!(!a.contains(98));
1542        assert!(!a.contains(3));
1543        assert!(!a.contains(0));
1544    }
1545
1546    #[test]
1547    fn test_bit_vec_remove() {
1548        let mut a = BitSet::new();
1549
1550        assert!(a.insert(1));
1551        assert!(a.remove(1));
1552
1553        assert!(a.insert(100));
1554        assert!(a.remove(100));
1555
1556        assert!(a.insert(1000));
1557        assert!(a.remove(1000));
1558        a.shrink_to_fit();
1559    }
1560
1561    #[test]
1562    fn test_bit_vec_clone() {
1563        let mut a = BitSet::new();
1564
1565        assert!(a.insert(1));
1566        assert!(a.insert(100));
1567        assert!(a.insert(1000));
1568
1569        let mut b = a.clone();
1570
1571        assert!(a == b);
1572
1573        assert!(b.remove(1));
1574        assert!(a.contains(1));
1575
1576        assert!(a.remove(1000));
1577        assert!(b.contains(1000));
1578    }
1579
1580    #[test]
1581    fn test_truncate() {
1582        let bytes = [0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF];
1583
1584        let mut s = BitSet::from_bytes(&bytes);
1585        s.truncate(5 * 8);
1586
1587        assert_eq!(s, BitSet::from_bytes(&bytes[..5]));
1588        assert_eq!(s.len(), 5 * 8);
1589        s.truncate(4 * 8);
1590        assert_eq!(s, BitSet::from_bytes(&bytes[..4]));
1591        assert_eq!(s.len(), 4 * 8);
1592        // Truncating to a size > s.len() should be a noop
1593        s.truncate(5 * 8);
1594        assert_eq!(s, BitSet::from_bytes(&bytes[..4]));
1595        assert_eq!(s.len(), 4 * 8);
1596        s.truncate(8);
1597        assert_eq!(s, BitSet::from_bytes(&bytes[..1]));
1598        assert_eq!(s.len(), 8);
1599        s.truncate(0);
1600        assert_eq!(s, BitSet::from_bytes(&[]));
1601        assert_eq!(s.len(), 0);
1602    }
1603
1604    #[cfg(feature = "serde")]
1605    #[test]
1606    fn test_serialization() {
1607        let bset: BitSet = BitSet::new();
1608        let serialized = serde_json::to_string(&bset).unwrap();
1609        let unserialized: BitSet = serde_json::from_str(&serialized).unwrap();
1610        assert_eq!(bset, unserialized);
1611
1612        let elems: Vec<usize> = vec![11, 42, 100, 101];
1613        let bset: BitSet = elems.iter().map(|n| *n).collect();
1614        let serialized = serde_json::to_string(&bset).unwrap();
1615        let unserialized = serde_json::from_str(&serialized).unwrap();
1616        assert_eq!(bset, unserialized);
1617    }
1618
1619    /*
1620        #[test]
1621        fn test_bit_set_append() {
1622            let mut a = BitSet::new();
1623            a.insert(2);
1624            a.insert(6);
1625
1626            let mut b = BitSet::new();
1627            b.insert(1);
1628            b.insert(3);
1629            b.insert(6);
1630
1631            a.append(&mut b);
1632
1633            assert_eq!(a.len(), 4);
1634            assert_eq!(b.len(), 0);
1635            assert!(b.capacity() >= 6);
1636
1637            assert_eq!(a, BitSet::from_bytes(&[0b01110010]));
1638        }
1639
1640        #[test]
1641        fn test_bit_set_split_off() {
1642            // Split at 0
1643            let mut a = BitSet::from_bytes(&[0b10100000, 0b00010010, 0b10010010,
1644                                             0b00110011, 0b01101011, 0b10101101]);
1645
1646            let b = a.split_off(0);
1647
1648            assert_eq!(a.len(), 0);
1649            assert_eq!(b.len(), 21);
1650
1651            assert_eq!(b, BitSet::from_bytes(&[0b10100000, 0b00010010, 0b10010010,
1652                                               0b00110011, 0b01101011, 0b10101101]);
1653
1654            // Split behind last element
1655            let mut a = BitSet::from_bytes(&[0b10100000, 0b00010010, 0b10010010,
1656                                             0b00110011, 0b01101011, 0b10101101]);
1657
1658            let b = a.split_off(50);
1659
1660            assert_eq!(a.len(), 21);
1661            assert_eq!(b.len(), 0);
1662
1663            assert_eq!(a, BitSet::from_bytes(&[0b10100000, 0b00010010, 0b10010010,
1664                                               0b00110011, 0b01101011, 0b10101101]));
1665
1666            // Split at arbitrary element
1667            let mut a = BitSet::from_bytes(&[0b10100000, 0b00010010, 0b10010010,
1668                                             0b00110011, 0b01101011, 0b10101101]);
1669
1670            let b = a.split_off(34);
1671
1672            assert_eq!(a.len(), 12);
1673            assert_eq!(b.len(), 9);
1674
1675            assert_eq!(a, BitSet::from_bytes(&[0b10100000, 0b00010010, 0b10010010,
1676                                               0b00110011, 0b01000000]));
1677            assert_eq!(b, BitSet::from_bytes(&[0, 0, 0, 0,
1678                                               0b00101011, 0b10101101]));
1679        }
1680    */
1681}
bit_set/lib.rs

bit_set/
lib.rs
