// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
//
http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
//
http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or
http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! # Description
//!
//! An implementation of a set using a bit vector as an underlying
//! representation for holding unsigned numerical elements.
//!
//! It should also be noted that the amount of storage necessary for holding a
//! set of objects is proportional to the maximum of the objects when viewed
//! as a `usize`.
//!
//! # Examples
//!
//! ```
//! use bit_set::BitSet;
//!
//! // It's a regular set
//! let mut s = BitSet::new();
//! s.insert(0);
//! s.insert(3);
//! s.insert(7);
//!
//! s.remove(7);
//!
//! if !s.contains(7) {
//! println!("There is no 7");
//! }
//!
//! // Can initialize from a `BitVec`
//! let other = BitSet::from_bytes(&[0b11010000]);
//!
//! s.union_with(&other);
//!
//! // Print 0, 1, 3 in some order
//! for x in s.iter() {
//! println!("{}", x);
//! }
//!
//! // Can convert back to a `BitVec`
//! let bv = s.into_bit_vec();
//! assert!(bv[3]);
//! ```
#![doc(html_root_url = "
https://docs.rs/bit-set/0.8.0")]
#![no_std]
extern crate bit_vec;
#[cfg(feature = "serde")]
extern crate serde;
#[cfg(any(test, feature = "std"))]
extern crate std;
use bit_vec::{BitBlock, BitVec, Blocks};
use core::cmp;
use core::cmp::Ordering;
use core::fmt;
use core::hash;
use core::iter::{self, Chain, Enumerate, FromIterator, Repeat, Skip, Take};
type MatchWords<'a, B> = Chain<Enumerate<Blocks<'a, B>>, Skip<Take<Enumerate<Repeat<B>>>>>;
/// Computes how many blocks are needed to store that many bits
fn blocks_for_bits<B: BitBlock>(bits: usize) -> usize {
// If we want 17 bits, dividing by 32 will produce 0. So we add 1 to make sure we
// reserve enough. But if we want exactly a multiple of 32, this will actually allocate
// one too many. So we need to check if that's the case. We can do that by computing if
// bitwise AND by `32 - 1` is 0. But LLVM should be able to optimize the semantically
// superior modulo operator on a power of two to this.
//
// Note that we can technically avoid this branch with the expression
// `(nbits + BITS - 1) / 32::BITS`, but if nbits is almost usize::MAX this will overflow.
if bits % B::bits() == 0 {
bits / B::bits()
} else {
bits / B::bits() + 1
}
}
#[allow(clippy::iter_skip_zero)]
// Take two BitVec's, and return iterators of their words, where the shorter one
// has been padded with 0's
fn match_words<'a, 'b, B: BitBlock>(
a: &'a BitVec<B>,
b: &'b BitVec<B>,
) -> (MatchWords<'a, B>, MatchWords<'b, B>) {
let a_len = a.storage().len();
let b_len = b.storage().len();
// have to uselessly pretend to pad the longer one for type matching
if a_len < b_len {
(
a.blocks()
.enumerate()
.chain(iter::repeat(B::zero()).enumerate().take(b_len).skip(a_len)),
b.blocks()
.enumerate()
.chain(iter::repeat(B::zero()).enumerate().take(0).skip(0)),
)
} else {
(
a.blocks()
.enumerate()
.chain(iter::repeat(B::zero()).enumerate().take(0).skip(0)),
b.blocks()
.enumerate()
.chain(iter::repeat(B::zero()).enumerate().take(a_len).skip(b_len)),
)
}
}
#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
pub struct BitSet<B = u32> {
bit_vec: BitVec<B>,
}
impl<B: BitBlock> Clone for BitSet<B> {
fn clone(&self) -> Self {
BitSet {
bit_vec: self.bit_vec.clone(),
}
}
fn clone_from(&mut self, other: &Self) {
self.bit_vec.clone_from(&other.bit_vec);
}
}
impl<B: BitBlock> Default for BitSet<B> {
#[inline]
fn default() -> Self {
BitSet {
bit_vec: Default::default(),
}
}
}
impl<B: BitBlock> FromIterator<usize> for BitSet<B> {
fn from_iter<I: IntoIterator<Item = usize>>(iter: I) -> Self {
let mut ret = Self::default();
ret.extend(iter);
ret
}
}
impl<B: BitBlock> Extend<usize> for BitSet<B> {
#[inline]
fn extend<I: IntoIterator<Item = usize>>(&mut self, iter: I) {
for i in iter {
self.insert(i);
}
}
}
impl<B: BitBlock> PartialOrd for BitSet<B> {
#[inline]
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
Some(self.cmp(other))
}
}
impl<B: BitBlock> Ord for BitSet<B> {
#[inline]
fn cmp(&self, other: &Self) -> Ordering {
self.iter().cmp(other)
}
}
impl<B: BitBlock> PartialEq for BitSet<B> {
#[inline]
fn eq(&self, other: &Self) -> bool {
self.iter().eq(other)
}
}
impl<B: BitBlock> Eq for BitSet<B> {}
impl BitSet<u32> {
/// Creates a new empty `BitSet`.
///
/// # Examples
///
/// ```
/// use bit_set::BitSet;
///
/// let mut s = BitSet::new();
/// ```
#[inline]
pub fn new() -> Self {
Self::default()
}
/// Creates a new `BitSet` with initially no contents, able to
/// hold `nbits` elements without resizing.
///
/// # Examples
///
/// ```
/// use bit_set::BitSet;
///
/// let mut s = BitSet::with_capacity(100);
/// assert!(s.capacity() >= 100);
/// ```
#[inline]
pub fn with_capacity(nbits: usize) -> Self {
let bit_vec = BitVec::from_elem(nbits, false);
Self::from_bit_vec(bit_vec)
}
/// Creates a new `BitSet` from the given bit vector.
///
/// # Examples
///
/// ```
/// extern crate bit_vec;
/// extern crate bit_set;
///
/// fn main() {
/// use bit_vec::BitVec;
/// use bit_set::BitSet;
///
/// let bv = BitVec::from_bytes(&[0b01100000]);
/// let s = BitSet::from_bit_vec(bv);
///
/// // Print 1, 2 in arbitrary order
/// for x in s.iter() {
/// println!("{}", x);
/// }
/// }
/// ```
#[inline]
pub fn from_bit_vec(bit_vec: BitVec) -> Self {
BitSet { bit_vec }
}
pub fn from_bytes(bytes: &[u8]) -> Self {
BitSet {
bit_vec: BitVec::from_bytes(bytes),
}
}
}
impl<B: BitBlock> BitSet<B> {
/// Returns the capacity in bits for this bit vector. Inserting any
/// element less than this amount will not trigger a resizing.
///
/// # Examples
///
/// ```
/// use bit_set::BitSet;
///
/// let mut s = BitSet::with_capacity(100);
/// assert!(s.capacity() >= 100);
/// ```
#[inline]
pub fn capacity(&self) -> usize {
self.bit_vec.capacity()
}
/// Reserves capacity for the given `BitSet` to contain `len` distinct elements. In the case
/// of `BitSet` this means reallocations will not occur as long as all inserted elements
/// are less than `len`.
///
/// The collection may reserve more space to avoid frequent reallocations.
///
///
/// # Examples
///
/// ```
/// use bit_set::BitSet;
///
/// let mut s = BitSet::new();
/// s.reserve_len(10);
/// assert!(s.capacity() >= 10);
/// ```
pub fn reserve_len(&mut self, len: usize) {
let cur_len = self.bit_vec.len();
if len >= cur_len {
self.bit_vec.reserve(len - cur_len);
}
}
/// Reserves the minimum capacity for the given `BitSet` to contain `len` distinct elements.
/// In the case of `BitSet` this means reallocations will not occur as long as all inserted
/// elements are less than `len`.
///
/// Note that the allocator may give the collection more space than it requests. Therefore
/// capacity can not be relied upon to be precisely minimal. Prefer `reserve_len` if future
/// insertions are expected.
///
///
/// # Examples
///
/// ```
/// use bit_set::BitSet;
///
/// let mut s = BitSet::new();
/// s.reserve_len_exact(10);
/// assert!(s.capacity() >= 10);
/// ```
pub fn reserve_len_exact(&mut self, len: usize) {
let cur_len = self.bit_vec.len();
if len >= cur_len {
self.bit_vec.reserve_exact(len - cur_len);
}
}
/// Consumes this set to return the underlying bit vector.
///
/// # Examples
///
/// ```
/// use bit_set::BitSet;
///
/// let mut s = BitSet::new();
/// s.insert(0);
/// s.insert(3);
///
/// let bv = s.into_bit_vec();
/// assert!(bv[0]);
/// assert!(bv[3]);
/// ```
#[inline]
pub fn into_bit_vec(self) -> BitVec<B> {
self.bit_vec
}
/// Returns a reference to the underlying bit vector.
///
/// # Examples
///
/// ```
/// use bit_set::BitSet;
///
/// let mut set = BitSet::new();
/// set.insert(0);
///
/// let bv = set.get_ref();
/// assert_eq!(bv[0], true);
/// ```
#[inline]
pub fn get_ref(&self) -> &BitVec<B> {
&self.bit_vec
}
/// Returns a mutable reference to the underlying bit vector.
///
/// # Examples
///
/// ```
/// use bit_set::BitSet;
///
/// let mut set = BitSet::new();
/// set.insert(0);
/// set.insert(3);
///
/// {
/// let bv = set.get_mut();
/// bv.set(1, true);
/// }
///
/// assert!(set.contains(0));
/// assert!(set.contains(1));
/// assert!(set.contains(3));
/// ```
#[inline]
pub fn get_mut(&mut self) -> &mut BitVec<B> {
&mut self.bit_vec
}
#[inline]
fn other_op<F>(&mut self, other: &Self, mut f: F)
where
F: FnMut(B, B) -> B,
{
// Unwrap BitVecs
let self_bit_vec = &mut self.bit_vec;
let other_bit_vec = &other.bit_vec;
let self_len = self_bit_vec.len();
let other_len = other_bit_vec.len();
// Expand the vector if necessary
if self_len < other_len {
self_bit_vec.grow(other_len - self_len, false);
}
// virtually pad other with 0's for equal lengths
let other_words = {
let (_, result) = match_words(self_bit_vec, other_bit_vec);
result
};
// Apply values found in other
for (i, w) in other_words {
let old = self_bit_vec.storage()[i];
let new = f(old, w);
unsafe {
self_bit_vec.storage_mut()[i] = new;
}
}
}
/// Truncates the underlying vector to the least length required.
///
/// # Examples
///
/// ```
/// use bit_set::BitSet;
///
/// let mut s = BitSet::new();
/// s.insert(3231);
/// s.remove(3231);
///
/// // Internal storage will probably be bigger than necessary
/// println!("old capacity: {}", s.capacity());
/// assert!(s.capacity() >= 3231);
///
/// // Now should be smaller
/// s.shrink_to_fit();
/// println!("new capacity: {}", s.capacity());
/// ```
#[inline]
pub fn shrink_to_fit(&mut self) {
let bit_vec = &mut self.bit_vec;
// Obtain original length
let old_len = bit_vec.storage().len();
// Obtain coarse trailing zero length
let n = bit_vec
.storage()
.iter()
.rev()
.take_while(|&&n| n == B::zero())
.count();
// Truncate away all empty trailing blocks, then shrink_to_fit
let trunc_len = old_len - n;
unsafe {
bit_vec.storage_mut().truncate(trunc_len);
bit_vec.set_len(trunc_len * B::bits());
}
bit_vec.shrink_to_fit();
}
/// Iterator over each usize stored in the `BitSet`.
///
/// # Examples
///
/// ```
/// use bit_set::BitSet;
///
/// let s = BitSet::from_bytes(&[0b01001010]);
///
/// // Print 1, 4, 6 in arbitrary order
/// for x in s.iter() {
/// println!("{}", x);
/// }
/// ```
#[inline]
pub fn iter(&self) -> Iter<B> {
Iter(BlockIter::from_blocks(self.bit_vec.blocks()))
}
/// Iterator over each usize stored in `self` union `other`.
/// See [`union_with`] for an efficient in-place version.
///
/// # Examples
///
/// ```
/// use bit_set::BitSet;
///
/// let a = BitSet::from_bytes(&[0b01101000]);
/// let b = BitSet::from_bytes(&[0b10100000]);
///
/// // Print 0, 1, 2, 4 in arbitrary order
/// for x in a.union(&b) {
/// println!("{}", x);
/// }
/// ```
///
/// [`union_with`]: Self::union_with
#[inline]
pub fn union<'a>(&'a self, other: &'a Self) -> Union<'a, B> {
fn or<B: BitBlock>(w1: B, w2: B) -> B {
w1 | w2
}
Union(BlockIter::from_blocks(TwoBitPositions {
set: self.bit_vec.blocks(),
other: other.bit_vec.blocks(),
merge: or,
}))
}
/// Iterator over each usize stored in `self` intersect `other`.
/// See [`intersect_with`] for an efficient in-place version.
///
/// # Examples
///
/// ```
/// use bit_set::BitSet;
///
/// let a = BitSet::from_bytes(&[0b01101000]);
/// let b = BitSet::from_bytes(&[0b10100000]);
///
/// // Print 2
/// for x in a.intersection(&b) {
/// println!("{}", x);
/// }
/// ```
///
/// [`intersect_with`]: Self::intersect_with
#[inline]
pub fn intersection<'a>(&'a self, other: &'a Self) -> Intersection<'a, B> {
fn bitand<B: BitBlock>(w1: B, w2: B) -> B {
w1 & w2
}
let min = cmp::min(self.bit_vec.len(), other.bit_vec.len());
Intersection {
iter: BlockIter::from_blocks(TwoBitPositions {
set: self.bit_vec.blocks(),
other: other.bit_vec.blocks(),
merge: bitand,
}),
n: min,
}
}
/// Iterator over each usize stored in the `self` setminus `other`.
/// See [`difference_with`] for an efficient in-place version.
///
/// # Examples
///
/// ```
/// use bit_set::BitSet;
///
/// let a = BitSet::from_bytes(&[0b01101000]);
/// let b = BitSet::from_bytes(&[0b10100000]);
///
/// // Print 1, 4 in arbitrary order
/// for x in a.difference(&b) {
/// println!("{}", x);
/// }
///
/// // Note that difference is not symmetric,
/// // and `b - a` means something else.
/// // This prints 0
/// for x in b.difference(&a) {
/// println!("{}", x);
/// }
/// ```
///
/// [`difference_with`]: Self::difference_with
#[inline]
pub fn difference<'a>(&'a self, other: &'a Self) -> Difference<'a, B> {
fn diff<B: BitBlock>(w1: B, w2: B) -> B {
w1 & !w2
}
Difference(BlockIter::from_blocks(TwoBitPositions {
set: self.bit_vec.blocks(),
other: other.bit_vec.blocks(),
merge: diff,
}))
}
/// Iterator over each usize stored in the symmetric difference of `self` and `other`.
/// See [`symmetric_difference_with`] for an efficient in-place version.
///
/// # Examples
///
/// ```
/// use bit_set::BitSet;
///
/// let a = BitSet::from_bytes(&[0b01101000]);
/// let b = BitSet::from_bytes(&[0b10100000]);
///
/// // Print 0, 1, 4 in arbitrary order
/// for x in a.symmetric_difference(&b) {
/// println!("{}", x);
/// }
/// ```
///
/// [`symmetric_difference_with`]: Self::symmetric_difference_with
#[inline]
pub fn symmetric_difference<'a>(&'a self, other: &'a Self) -> SymmetricDifference<'a, B> {
fn bitxor<B: BitBlock>(w1: B, w2: B) -> B {
w1 ^ w2
}
SymmetricDifference(BlockIter::from_blocks(TwoBitPositions {
set: self.bit_vec.blocks(),
other: other.bit_vec.blocks(),
merge: bitxor,
}))
}
/// Unions in-place with the specified other bit vector.
///
/// # Examples
///
/// ```
/// use bit_set::BitSet;
///
/// let a = 0b01101000;
/// let b = 0b10100000;
/// let res = 0b11101000;
///
/// let mut a = BitSet::from_bytes(&[a]);
/// let b = BitSet::from_bytes(&[b]);
/// let res = BitSet::from_bytes(&[res]);
///
/// a.union_with(&b);
/// assert_eq!(a, res);
/// ```
#[inline]
pub fn union_with(&mut self, other: &Self) {
self.other_op(other, |w1, w2| w1 | w2);
}
/// Intersects in-place with the specified other bit vector.
///
/// # Examples
///
/// ```
/// use bit_set::BitSet;
///
/// let a = 0b01101000;
/// let b = 0b10100000;
/// let res = 0b00100000;
///
/// let mut a = BitSet::from_bytes(&[a]);
/// let b = BitSet::from_bytes(&[b]);
/// let res = BitSet::from_bytes(&[res]);
///
/// a.intersect_with(&b);
/// assert_eq!(a, res);
/// ```
#[inline]
pub fn intersect_with(&mut self, other: &Self) {
self.other_op(other, |w1, w2| w1 & w2);
}
/// Makes this bit vector the difference with the specified other bit vector
/// in-place.
///
/// # Examples
///
/// ```
/// use bit_set::BitSet;
///
/// let a = 0b01101000;
/// let b = 0b10100000;
/// let a_b = 0b01001000; // a - b
/// let b_a = 0b10000000; // b - a
///
/// let mut bva = BitSet::from_bytes(&[a]);
/// let bvb = BitSet::from_bytes(&[b]);
/// let bva_b = BitSet::from_bytes(&[a_b]);
/// let bvb_a = BitSet::from_bytes(&[b_a]);
///
/// bva.difference_with(&bvb);
/// assert_eq!(bva, bva_b);
///
/// let bva = BitSet::from_bytes(&[a]);
/// let mut bvb = BitSet::from_bytes(&[b]);
///
/// bvb.difference_with(&bva);
/// assert_eq!(bvb, bvb_a);
/// ```
#[inline]
pub fn difference_with(&mut self, other: &Self) {
self.other_op(other, |w1, w2| w1 & !w2);
}
/// Makes this bit vector the symmetric difference with the specified other
/// bit vector in-place.
///
/// # Examples
///
/// ```
/// use bit_set::BitSet;
///
/// let a = 0b01101000;
/// let b = 0b10100000;
/// let res = 0b11001000;
///
/// let mut a = BitSet::from_bytes(&[a]);
/// let b = BitSet::from_bytes(&[b]);
/// let res = BitSet::from_bytes(&[res]);
///
/// a.symmetric_difference_with(&b);
/// assert_eq!(a, res);
/// ```
#[inline]
pub fn symmetric_difference_with(&mut self, other: &Self) {
self.other_op(other, |w1, w2| w1 ^ w2);
}
/*
/// Moves all elements from `other` into `Self`, leaving `other` empty.
///
/// # Examples
///
/// ```
/// use bit_set::BitSet;
///
/// let mut a = BitSet::new();
/// a.insert(2);
/// a.insert(6);
///
/// let mut b = BitSet::new();
/// b.insert(1);
/// b.insert(3);
/// b.insert(6);
///
/// a.append(&mut b);
///
/// assert_eq!(a.len(), 4);
/// assert_eq!(b.len(), 0);
/// assert_eq!(a, BitSet::from_bytes(&[0b01110010]));
/// ```
pub fn append(&mut self, other: &mut Self) {
self.union_with(other);
other.clear();
}
/// Splits the `BitSet` into two at the given key including the key.
/// Retains the first part in-place while returning the second part.
///
/// # Examples
///
/// ```
/// use bit_set::BitSet;
///
/// let mut a = BitSet::new();
/// a.insert(2);
/// a.insert(6);
/// a.insert(1);
/// a.insert(3);
///
/// let b = a.split_off(3);
///
/// assert_eq!(a.len(), 2);
/// assert_eq!(b.len(), 2);
/// assert_eq!(a, BitSet::from_bytes(&[0b01100000]));
/// assert_eq!(b, BitSet::from_bytes(&[0b00010010]));
/// ```
pub fn split_off(&mut self, at: usize) -> Self {
let mut other = BitSet::new();
if at == 0 {
swap(self, &mut other);
return other;
} else if at >= self.bit_vec.len() {
return other;
}
// Calculate block and bit at which to split
let w = at / BITS;
let b = at % BITS;
// Pad `other` with `w` zero blocks,
// append `self`'s blocks in the range from `w` to the end to `other`
other.bit_vec.storage_mut().extend(repeat(0u32).take(w)
.chain(self.bit_vec.storage()[w..].iter().cloned()));
other.bit_vec.nbits = self.bit_vec.nbits;
if b > 0 {
other.bit_vec.storage_mut()[w] &= !0 << b;
}
// Sets `bit_vec.len()` and fixes the last block as well
self.bit_vec.truncate(at);
other
}
*/
/// Returns the number of set bits in this set.
#[inline]
pub fn len(&self) -> usize {
self.bit_vec.blocks().fold(0, |acc, n| acc + n.count_ones())
}
/// Returns whether there are no bits set in this set
#[inline]
pub fn is_empty(&self) -> bool {
self.bit_vec.none()
}
/// Clears all bits in this set
#[inline]
pub fn clear(&mut self) {
self.bit_vec.clear();
}
/// Returns `true` if this set contains the specified integer.
#[inline]
pub fn contains(&self, value: usize) -> bool {
let bit_vec = &self.bit_vec;
value < bit_vec.len() && bit_vec[value]
}
/// Returns `true` if the set has no elements in common with `other`.
/// This is equivalent to checking for an empty intersection.
#[inline]
pub fn is_disjoint(&self, other: &Self) -> bool {
self.intersection(other).next().is_none()
}
/// Returns `true` if the set is a subset of another.
#[inline]
pub fn is_subset(&self, other: &Self) -> bool {
let self_bit_vec = &self.bit_vec;
let other_bit_vec = &other.bit_vec;
let other_blocks = blocks_for_bits::<B>(other_bit_vec.len());
// Check that `self` intersect `other` is self
self_bit_vec.blocks().zip(other_bit_vec.blocks()).all(|(w1, w2)| w1 & w2 == w1) &&
// Make sure if `self` has any more blocks than `other`, they're all 0
self_bit_vec.blocks().skip(other_blocks).all(|w| w == B::zero())
}
/// Returns `true` if the set is a superset of another.
#[inline]
pub fn is_superset(&self, other: &Self) -> bool {
other.is_subset(self)
}
/// Adds a value to the set. Returns `true` if the value was not already
/// present in the set.
pub fn insert(&mut self, value: usize) -> bool {
if self.contains(value) {
return false;
}
// Ensure we have enough space to hold the new element
let len = self.bit_vec.len();
if value >= len {
self.bit_vec.grow(value - len + 1, false);
}
self.bit_vec.set(value, true);
true
}
/// Removes a value from the set. Returns `true` if the value was
/// present in the set.
pub fn remove(&mut self, value: usize) -> bool {
if !self.contains(value) {
return false;
}
self.bit_vec.set(value, false);
true
}
/// Excludes `element` and all greater elements from the `BitSet`.
pub fn truncate(&mut self, element: usize) {
self.bit_vec.truncate(element);
}
}
impl<B: BitBlock> fmt::Debug for BitSet<B> {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
fmt.debug_set().entries(self).finish()
}
}
impl<B: BitBlock> hash::Hash for BitSet<B> {
fn hash<H: hash::Hasher>(&self, state: &mut H) {
for pos in self {
pos.hash(state);
}
}
}
#[derive(Clone)]
struct BlockIter<T, B> {
head: B,
head_offset: usize,
tail: T,
}
impl<T, B: BitBlock> BlockIter<T, B>
where
T: Iterator<Item = B>,
{
fn from_blocks(mut blocks: T) -> BlockIter<T, B> {
let h = blocks.next().unwrap_or_else(B::zero);
BlockIter {
tail: blocks,
head: h,
head_offset: 0,
}
}
}
/// An iterator combining two `BitSet` iterators.
#[derive(Clone)]
struct TwoBitPositions<'a, B: 'a> {
set: Blocks<'a, B>,
other: Blocks<'a, B>,
merge: fn(B, B) -> B,
}
/// An iterator for `BitSet`.
#[derive(Clone)]
pub struct Iter<'a, B: 'a>(BlockIter<Blocks<'a, B>, B>);
#[derive(Clone)]
pub struct Union<'a, B: 'a>(BlockIter<TwoBitPositions<'a, B>, B>);
#[derive(Clone)]
pub struct Intersection<'a, B: 'a> {
iter: BlockIter<TwoBitPositions<'a, B>, B>,
// as an optimization, we compute the maximum possible
// number of elements in the intersection, and count it
// down as we return elements. If we reach zero, we can
// stop.
n: usize,
}
#[derive(Clone)]
pub struct Difference<'a, B: 'a>(BlockIter<TwoBitPositions<'a, B>, B>);
#[derive(Clone)]
pub struct SymmetricDifference<'a, B: 'a>(BlockIter<TwoBitPositions<'a, B>, B>);
impl<T, B: BitBlock> Iterator for BlockIter<T, B>
where
T: Iterator<Item = B>,
{
type Item = usize;
fn next(&mut self) -> Option<usize> {
while self.head == B::zero() {
match self.tail.next() {
Some(w) => self.head = w,
None => return None,
}
self.head_offset += B::bits();
}
// from the current block, isolate the
// LSB and subtract 1, producing k:
// a block with a number of set bits
// equal to the index of the LSB
let k = (self.head & (!self.head + B::one())) - B::one();
// update block, removing the LSB
self.head = self.head & (self.head - B::one());
// return offset + (index of LSB)
Some(self.head_offset + (B::count_ones(k)))
}
fn count(self) -> usize {
self.head.count_ones() + self.tail.map(|block| block.count_ones()).sum::<usize>()
}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
match self.tail.size_hint() {
(_, Some(h)) => (0, Some((1 + h) * B::bits())),
_ => (0, None),
}
}
}
impl<'a, B: BitBlock> Iterator for TwoBitPositions<'a, B> {
type Item = B;
fn next(&mut self) -> Option<B> {
match (self.set.next(), self.other.next()) {
(Some(a), Some(b)) => Some((self.merge)(a, b)),
(Some(a), None) => Some((self.merge)(a, B::zero())),
(None, Some(b)) => Some((self.merge)(B::zero(), b)),
_ => None,
}
}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
let (a, au) = self.set.size_hint();
let (b, bu) = self.other.size_hint();
let upper = match (au, bu) {
(Some(au), Some(bu)) => Some(cmp::max(au, bu)),
_ => None,
};
(cmp::max(a, b), upper)
}
}
impl<'a, B: BitBlock> Iterator for Iter<'a, B> {
type Item = usize;
#[inline]
fn next(&mut self) -> Option<usize> {
self.0.next()
}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
self.0.size_hint()
}
#[inline]
fn count(self) -> usize {
self.0.count()
}
}
impl<'a, B: BitBlock> Iterator for Union<'a, B> {
type Item = usize;
#[inline]
fn next(&mut self) -> Option<usize> {
self.0.next()
}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
self.0.size_hint()
}
#[inline]
fn count(self) -> usize {
self.0.count()
}
}
impl<'a, B: BitBlock> Iterator for Intersection<'a, B> {
type Item = usize;
#[inline]
fn next(&mut self) -> Option<usize> {
if self.n != 0 {
self.n -= 1;
self.iter.next()
} else {
None
}
}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
// We could invoke self.iter.size_hint() and incorporate that into the hint.
// In practice, that does not seem worthwhile because the lower bound will
// always be zero and the upper bound could only possibly less then n in a
// partially iterated iterator. However, it makes little sense ask for size_hint
// in a partially iterated iterator, so it did not seem worthwhile.
(0, Some(self.n))
}
#[inline]
fn count(self) -> usize {
self.iter.count()
}
}
impl<'a, B: BitBlock> Iterator for Difference<'a, B> {
type Item = usize;
#[inline]
fn next(&mut self) -> Option<usize> {
self.0.next()
}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
self.0.size_hint()
}
#[inline]
fn count(self) -> usize {
self.0.count()
}
}
impl<'a, B: BitBlock> Iterator for SymmetricDifference<'a, B> {
type Item = usize;
#[inline]
fn next(&mut self) -> Option<usize> {
self.0.next()
}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
self.0.size_hint()
}
#[inline]
fn count(self) -> usize {
self.0.count()
}
}
impl<'a, B: BitBlock> IntoIterator for &'a BitSet<B> {
type Item = usize;
type IntoIter = Iter<'a, B>;
fn into_iter(self) -> Iter<'a, B> {
self.iter()
}
}
#[cfg(test)]
mod tests {
use super::BitSet;
use bit_vec::BitVec;
use std::cmp::Ordering::{Equal, Greater, Less};
use std::vec::Vec;
use std::{format, vec};
#[test]
fn test_bit_set_show() {
let mut s = BitSet::new();
s.insert(1);
s.insert(10);
s.insert(50);
s.insert(2);
assert_eq!("{1, 2, 10, 50}", format!("{:?}", s));
}
#[test]
fn test_bit_set_from_usizes() {
let usizes = vec![0, 2, 2, 3];
let a: BitSet = usizes.into_iter().collect();
let mut b = BitSet::new();
b.insert(0);
b.insert(2);
b.insert(3);
assert_eq!(a, b);
}
#[test]
fn test_bit_set_iterator() {
let usizes = vec![0, 2, 2, 3];
let bit_vec: BitSet = usizes.into_iter().collect();
let idxs: Vec<_> = bit_vec.iter().collect();
assert_eq!(idxs, [0, 2, 3]);
assert_eq!(bit_vec.iter().count(), 3);
let long: BitSet = (0..10000).filter(|&n| n % 2 == 0).collect();
let real: Vec<_> = (0..10000 / 2).map(|x| x * 2).collect();
let idxs: Vec<_> = long.iter().collect();
assert_eq!(idxs, real);
assert_eq!(long.iter().count(), real.len());
}
#[test]
fn test_bit_set_frombit_vec_init() {
let bools = [true, false];
let lengths = [10, 64, 100];
for &b in &bools {
for &l in &lengths {
let bitset = BitSet::from_bit_vec(BitVec::from_elem(l, b));
assert_eq!(bitset.contains(1), b);
assert_eq!(bitset.contains(l - 1), b);
assert!(!bitset.contains(l));
}
}
}
#[test]
fn test_bit_vec_masking() {
let b = BitVec::from_elem(140, true);
let mut bs = BitSet::from_bit_vec(b);
assert!(bs.contains(139));
assert!(!bs.contains(140));
assert!(bs.insert(150));
assert!(!bs.contains(140));
assert!(!bs.contains(149));
assert!(bs.contains(150));
assert!(!bs.contains(151));
}
#[test]
fn test_bit_set_basic() {
let mut b = BitSet::new();
assert!(b.insert(3));
assert!(!b.insert(3));
assert!(b.contains(3));
assert!(b.insert(4));
assert!(!b.insert(4));
assert!(b.contains(3));
assert!(b.insert(400));
assert!(!b.insert(400));
assert!(b.contains(400));
assert_eq!(b.len(), 3);
}
#[test]
fn test_bit_set_intersection() {
let mut a = BitSet::new();
let mut b = BitSet::new();
assert!(a.insert(11));
assert!(a.insert(1));
assert!(a.insert(3));
assert!(a.insert(77));
assert!(a.insert(103));
assert!(a.insert(5));
assert!(b.insert(2));
assert!(b.insert(11));
assert!(b.insert(77));
assert!(b.insert(5));
assert!(b.insert(3));
let expected = [3, 5, 11, 77];
let actual: Vec<_> = a.intersection(&b).collect();
assert_eq!(actual, expected);
assert_eq!(a.intersection(&b).count(), expected.len());
}
#[test]
fn test_bit_set_difference() {
let mut a = BitSet::new();
let mut b = BitSet::new();
assert!(a.insert(1));
assert!(a.insert(3));
assert!(a.insert(5));
assert!(a.insert(200));
assert!(a.insert(500));
assert!(b.insert(3));
assert!(b.insert(200));
let expected = [1, 5, 500];
let actual: Vec<_> = a.difference(&b).collect();
assert_eq!(actual, expected);
assert_eq!(a.difference(&b).count(), expected.len());
}
#[test]
fn test_bit_set_symmetric_difference() {
let mut a = BitSet::new();
let mut b = BitSet::new();
assert!(a.insert(1));
assert!(a.insert(3));
assert!(a.insert(5));
assert!(a.insert(9));
assert!(a.insert(11));
assert!(b.insert(3));
assert!(b.insert(9));
assert!(b.insert(14));
assert!(b.insert(220));
let expected = [1, 5, 11, 14, 220];
let actual: Vec<_> = a.symmetric_difference(&b).collect();
assert_eq!(actual, expected);
assert_eq!(a.symmetric_difference(&b).count(), expected.len());
}
#[test]
fn test_bit_set_union() {
let mut a = BitSet::new();
let mut b = BitSet::new();
assert!(a.insert(1));
assert!(a.insert(3));
assert!(a.insert(5));
assert!(a.insert(9));
assert!(a.insert(11));
assert!(a.insert(160));
assert!(a.insert(19));
assert!(a.insert(24));
assert!(a.insert(200));
assert!(b.insert(1));
assert!(b.insert(5));
assert!(b.insert(9));
assert!(b.insert(13));
assert!(b.insert(19));
let expected = [1, 3, 5, 9, 11, 13, 19, 24, 160, 200];
let actual: Vec<_> = a.union(&b).collect();
assert_eq!(actual, expected);
assert_eq!(a.union(&b).count(), expected.len());
}
#[test]
fn test_bit_set_subset() {
let mut set1 = BitSet::new();
let mut set2 = BitSet::new();
assert!(set1.is_subset(&set2)); // {} {}
set2.insert(100);
assert!(set1.is_subset(&set2)); // {} { 1 }
set2.insert(200);
assert!(set1.is_subset(&set2)); // {} { 1, 2 }
set1.insert(200);
assert!(set1.is_subset(&set2)); // { 2 } { 1, 2 }
set1.insert(300);
assert!(!set1.is_subset(&set2)); // { 2, 3 } { 1, 2 }
set2.insert(300);
assert!(set1.is_subset(&set2)); // { 2, 3 } { 1, 2, 3 }
set2.insert(400);
assert!(set1.is_subset(&set2)); // { 2, 3 } { 1, 2, 3, 4 }
set2.remove(100);
assert!(set1.is_subset(&set2)); // { 2, 3 } { 2, 3, 4 }
set2.remove(300);
assert!(!set1.is_subset(&set2)); // { 2, 3 } { 2, 4 }
set1.remove(300);
assert!(set1.is_subset(&set2)); // { 2 } { 2, 4 }
}
#[test]
fn test_bit_set_is_disjoint() {
let a = BitSet::from_bytes(&[0b10100010]);
let b = BitSet::from_bytes(&[0b01000000]);
let c = BitSet::new();
let d = BitSet::from_bytes(&[0b00110000]);
assert!(!a.is_disjoint(&d));
assert!(!d.is_disjoint(&a));
assert!(a.is_disjoint(&b));
assert!(a.is_disjoint(&c));
assert!(b.is_disjoint(&a));
assert!(b.is_disjoint(&c));
assert!(c.is_disjoint(&a));
assert!(c.is_disjoint(&b));
}
#[test]
fn test_bit_set_union_with() {
//a should grow to include larger elements
let mut a = BitSet::new();
a.insert(0);
let mut b = BitSet::new();
b.insert(5);
let expected = BitSet::from_bytes(&[0b10000100]);
a.union_with(&b);
assert_eq!(a, expected);
// Standard
let mut a = BitSet::from_bytes(&[0b10100010]);
let mut b = BitSet::from_bytes(&[0b01100010]);
let c = a.clone();
a.union_with(&b);
b.union_with(&c);
assert_eq!(a.len(), 4);
assert_eq!(b.len(), 4);
}
#[test]
fn test_bit_set_intersect_with() {
// Explicitly 0'ed bits
let mut a = BitSet::from_bytes(&[0b10100010]);
let mut b = BitSet::from_bytes(&[0b00000000]);
let c = a.clone();
a.intersect_with(&b);
b.intersect_with(&c);
assert!(a.is_empty());
assert!(b.is_empty());
// Uninitialized bits should behave like 0's
let mut a = BitSet::from_bytes(&[0b10100010]);
let mut b = BitSet::new();
let c = a.clone();
a.intersect_with(&b);
b.intersect_with(&c);
assert!(a.is_empty());
assert!(b.is_empty());
// Standard
let mut a = BitSet::from_bytes(&[0b10100010]);
let mut b = BitSet::from_bytes(&[0b01100010]);
let c = a.clone();
a.intersect_with(&b);
b.intersect_with(&c);
assert_eq!(a.len(), 2);
assert_eq!(b.len(), 2);
}
#[test]
fn test_bit_set_difference_with() {
// Explicitly 0'ed bits
let mut a = BitSet::from_bytes(&[0b00000000]);
let b = BitSet::from_bytes(&[0b10100010]);
a.difference_with(&b);
assert!(a.is_empty());
// Uninitialized bits should behave like 0's
let mut a = BitSet::new();
let b = BitSet::from_bytes(&[0b11111111]);
a.difference_with(&b);
assert!(a.is_empty());
// Standard
let mut a = BitSet::from_bytes(&[0b10100010]);
let mut b = BitSet::from_bytes(&[0b01100010]);
let c = a.clone();
a.difference_with(&b);
b.difference_with(&c);
assert_eq!(a.len(), 1);
assert_eq!(b.len(), 1);
}
#[test]
fn test_bit_set_symmetric_difference_with() {
//a should grow to include larger elements
let mut a = BitSet::new();
a.insert(0);
a.insert(1);
let mut b = BitSet::new();
b.insert(1);
b.insert(5);
let expected = BitSet::from_bytes(&[0b10000100]);
a.symmetric_difference_with(&b);
assert_eq!(a, expected);
let mut a = BitSet::from_bytes(&[0b10100010]);
let b = BitSet::new();
let c = a.clone();
a.symmetric_difference_with(&b);
assert_eq!(a, c);
// Standard
let mut a = BitSet::from_bytes(&[0b11100010]);
let mut b = BitSet::from_bytes(&[0b01101010]);
let c = a.clone();
a.symmetric_difference_with(&b);
b.symmetric_difference_with(&c);
assert_eq!(a.len(), 2);
assert_eq!(b.len(), 2);
}
#[test]
fn test_bit_set_eq() {
let a = BitSet::from_bytes(&[0b10100010]);
let b = BitSet::from_bytes(&[0b00000000]);
let c = BitSet::new();
assert!(a == a);
assert!(a != b);
assert!(a != c);
assert!(b == b);
assert!(b == c);
assert!(c == c);
}
#[test]
fn test_bit_set_cmp() {
let a = BitSet::from_bytes(&[0b10100010]);
let b = BitSet::from_bytes(&[0b00000000]);
let c = BitSet::new();
assert_eq!(a.cmp(&b), Greater);
assert_eq!(a.cmp(&c), Greater);
assert_eq!(b.cmp(&a), Less);
assert_eq!(b.cmp(&c), Equal);
assert_eq!(c.cmp(&a), Less);
assert_eq!(c.cmp(&b), Equal);
}
#[test]
fn test_bit_set_shrink_to_fit_new() {
// There was a strange bug where we refused to truncate to 0
// and this would end up actually growing the array in a way
// that (safely corrupted the state).
let mut a = BitSet::new();
assert_eq!(a.len(), 0);
assert_eq!(a.capacity(), 0);
a.shrink_to_fit();
assert_eq!(a.len(), 0);
assert_eq!(a.capacity(), 0);
assert!(!a.contains(1));
a.insert(3);
assert!(a.contains(3));
assert_eq!(a.len(), 1);
assert!(a.capacity() > 0);
a.shrink_to_fit();
assert!(a.contains(3));
assert_eq!(a.len(), 1);
assert!(a.capacity() > 0);
}
#[test]
fn test_bit_set_shrink_to_fit() {
let mut a = BitSet::new();
assert_eq!(a.len(), 0);
assert_eq!(a.capacity(), 0);
a.insert(259);
a.insert(98);
a.insert(3);
assert_eq!(a.len(), 3);
assert!(a.capacity() > 0);
assert!(!a.contains(1));
assert!(a.contains(259));
assert!(a.contains(98));
assert!(a.contains(3));
a.shrink_to_fit();
assert!(!a.contains(1));
assert!(a.contains(259));
assert!(a.contains(98));
assert!(a.contains(3));
assert_eq!(a.len(), 3);
assert!(a.capacity() > 0);
let old_cap = a.capacity();
assert!(a.remove(259));
a.shrink_to_fit();
assert!(a.capacity() < old_cap, "{} {}", a.capacity(), old_cap);
assert!(!a.contains(1));
assert!(!a.contains(259));
assert!(a.contains(98));
assert!(a.contains(3));
assert_eq!(a.len(), 2);
let old_cap2 = a.capacity();
a.clear();
assert_eq!(a.capacity(), old_cap2);
assert_eq!(a.len(), 0);
assert!(!a.contains(1));
assert!(!a.contains(259));
assert!(!a.contains(98));
assert!(!a.contains(3));
a.insert(512);
assert!(a.capacity() > 0);
assert_eq!(a.len(), 1);
assert!(a.contains(512));
assert!(!a.contains(1));
assert!(!a.contains(259));
assert!(!a.contains(98));
assert!(!a.contains(3));
a.remove(512);
a.shrink_to_fit();
assert_eq!(a.capacity(), 0);
assert_eq!(a.len(), 0);
assert!(!a.contains(512));
assert!(!a.contains(1));
assert!(!a.contains(259));
assert!(!a.contains(98));
assert!(!a.contains(3));
assert!(!a.contains(0));
}
#[test]
fn test_bit_vec_remove() {
let mut a = BitSet::new();
assert!(a.insert(1));
assert!(a.remove(1));
assert!(a.insert(100));
assert!(a.remove(100));
assert!(a.insert(1000));
assert!(a.remove(1000));
a.shrink_to_fit();
}
#[test]
fn test_bit_vec_clone() {
let mut a = BitSet::new();
assert!(a.insert(1));
assert!(a.insert(100));
assert!(a.insert(1000));
let mut b = a.clone();
assert!(a == b);
assert!(b.remove(1));
assert!(a.contains(1));
assert!(a.remove(1000));
assert!(b.contains(1000));
}
#[test]
fn test_truncate() {
let bytes = [0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF];
let mut s = BitSet::from_bytes(&bytes);
s.truncate(5 * 8);
assert_eq!(s, BitSet::from_bytes(&bytes[..5]));
assert_eq!(s.len(), 5 * 8);
s.truncate(4 * 8);
assert_eq!(s, BitSet::from_bytes(&bytes[..4]));
assert_eq!(s.len(), 4 * 8);
// Truncating to a size > s.len() should be a noop
s.truncate(5 * 8);
assert_eq!(s, BitSet::from_bytes(&bytes[..4]));
assert_eq!(s.len(), 4 * 8);
s.truncate(8);
assert_eq!(s, BitSet::from_bytes(&bytes[..1]));
assert_eq!(s.len(), 8);
s.truncate(0);
assert_eq!(s, BitSet::from_bytes(&[]));
assert_eq!(s.len(), 0);
}
#[cfg(feature = "serde")]
#[test]
fn test_serialization() {
let bset: BitSet = BitSet::new();
let serialized = serde_json::to_string(&bset).unwrap();
let unserialized: BitSet = serde_json::from_str(&serialized).unwrap();
assert_eq!(bset, unserialized);
let elems: Vec<usize> = vec![11, 42, 100, 101];
let bset: BitSet = elems.iter().map(|n| *n).collect();
let serialized = serde_json::to_string(&bset).unwrap();
let unserialized = serde_json::from_str(&serialized).unwrap();
assert_eq!(bset, unserialized);
}
/*
#[test]
fn test_bit_set_append() {
let mut a = BitSet::new();
a.insert(2);
a.insert(6);
let mut b = BitSet::new();
b.insert(1);
b.insert(3);
b.insert(6);
a.append(&mut b);
assert_eq!(a.len(), 4);
assert_eq!(b.len(), 0);
assert!(b.capacity() >= 6);
assert_eq!(a, BitSet::from_bytes(&[0b01110010]));
}
#[test]
fn test_bit_set_split_off() {
// Split at 0
let mut a = BitSet::from_bytes(&[0b10100000, 0b00010010, 0b10010010,
0b00110011, 0b01101011, 0b10101101]);
let b = a.split_off(0);
assert_eq!(a.len(), 0);
assert_eq!(b.len(), 21);
assert_eq!(b, BitSet::from_bytes(&[0b10100000, 0b00010010, 0b10010010,
0b00110011, 0b01101011, 0b10101101]);
// Split behind last element
let mut a = BitSet::from_bytes(&[0b10100000, 0b00010010, 0b10010010,
0b00110011, 0b01101011, 0b10101101]);
let b = a.split_off(50);
assert_eq!(a.len(), 21);
assert_eq!(b.len(), 0);
assert_eq!(a, BitSet::from_bytes(&[0b10100000, 0b00010010, 0b10010010,
0b00110011, 0b01101011, 0b10101101]));
// Split at arbitrary element
let mut a = BitSet::from_bytes(&[0b10100000, 0b00010010, 0b10010010,
0b00110011, 0b01101011, 0b10101101]);
let b = a.split_off(34);
assert_eq!(a.len(), 12);
assert_eq!(b.len(), 9);
assert_eq!(a, BitSet::from_bytes(&[0b10100000, 0b00010010, 0b10010010,
0b00110011, 0b01000000]));
assert_eq!(b, BitSet::from_bytes(&[0, 0, 0, 0,
0b00101011, 0b10101101]));
}
*/
}
