4daa62a55f
Some modest running-time improvements to `std::collections::BitSet` on bit-sets of varying set-membership densities. This is work originally from [here](https://github.com/rayglover/alt_collections). (Benchmarks copied below) ``` std::collections::BitSet / alt_collections::BitSet copy_dense ... 3.08x copy_sparse ... 4.22x count_dense ... 11.01x count_sparse ... 8.11x from_bytes ... 1.47x intersect_dense ... 6.54x intersect_sparse ... 4.37x union_dense ... 5.53x union_sparse ... 5.60x ``` The exception is `from_bytes`, which I've left unaltered since the optimization is rather obscure. Compiling with the cpu feature `popcnt` gave a further ~10% improvement on my machine, but this wasn't factored in to the benchmarks above. Similar improvements could be made to `BitVec`, although that would probably require more substantial changes. criticism welcome!
2139 lines
63 KiB
Rust
2139 lines
63 KiB
Rust
// 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.
|
|
|
|
// FIXME(Gankro): BitVec and BitSet are very tightly coupled. Ideally (for
|
|
// maintenance), they should be in separate files/modules, with BitSet only
|
|
// using BitVec's public API. This will be hard for performance though, because
|
|
// `BitVec` will not want to leak its internal representation while its internal
|
|
// representation as `u32`s must be assumed for best performance.
|
|
|
|
// FIXME(tbu-): `BitVec`'s methods shouldn't be `union`, `intersection`, but
|
|
// rather `or` and `and`.
|
|
|
|
// (1) Be careful, most things can overflow here because the amount of bits in
|
|
// memory can overflow `usize`.
|
|
// (2) Make sure that the underlying vector has no excess length:
|
|
// E. g. `nbits == 16`, `storage.len() == 2` would be excess length,
|
|
// because the last word isn't used at all. This is important because some
|
|
// methods rely on it (for *CORRECTNESS*).
|
|
// (3) Make sure that the unused bits in the last word are zeroed out, again
|
|
// other methods rely on it for *CORRECTNESS*.
|
|
// (4) `BitSet` is tightly coupled with `BitVec`, so any changes you make in
|
|
// `BitVec` will need to be reflected in `BitSet`.
|
|
|
|
//! Collections implemented with bit vectors.
|
|
//!
|
|
//! # Examples
|
|
//!
|
|
//! This is a simple example of the [Sieve of Eratosthenes][sieve]
|
|
//! which calculates prime numbers up to a given limit.
|
|
//!
|
|
//! [sieve]: http://en.wikipedia.org/wiki/Sieve_of_Eratosthenes
|
|
//!
|
|
//! ```
|
|
//! # #![feature(collections, core, step_by)]
|
|
//! use std::collections::{BitSet, BitVec};
|
|
//! use std::iter;
|
|
//!
|
|
//! let max_prime = 10000;
|
|
//!
|
|
//! // Store the primes as a BitSet
|
|
//! let primes = {
|
|
//! // Assume all numbers are prime to begin, and then we
|
|
//! // cross off non-primes progressively
|
|
//! let mut bv = BitVec::from_elem(max_prime, true);
|
|
//!
|
|
//! // Neither 0 nor 1 are prime
|
|
//! bv.set(0, false);
|
|
//! bv.set(1, false);
|
|
//!
|
|
//! for i in iter::range_inclusive(2, (max_prime as f64).sqrt() as usize) {
|
|
//! // if i is a prime
|
|
//! if bv[i] {
|
|
//! // Mark all multiples of i as non-prime (any multiples below i * i
|
|
//! // will have been marked as non-prime previously)
|
|
//! for j in (i * i..max_prime).step_by(i) { bv.set(j, false) }
|
|
//! }
|
|
//! }
|
|
//! BitSet::from_bit_vec(bv)
|
|
//! };
|
|
//!
|
|
//! // Simple primality tests below our max bound
|
|
//! let print_primes = 20;
|
|
//! print!("The primes below {} are: ", print_primes);
|
|
//! for x in 0..print_primes {
|
|
//! if primes.contains(&x) {
|
|
//! print!("{} ", x);
|
|
//! }
|
|
//! }
|
|
//! println!("");
|
|
//!
|
|
//! // We can manipulate the internal BitVec
|
|
//! let num_primes = primes.get_ref().iter().filter(|x| *x).count();
|
|
//! println!("There are {} primes below {}", num_primes, max_prime);
|
|
//! ```
|
|
|
|
use core::prelude::*;
|
|
|
|
use core::cmp::Ordering;
|
|
use core::cmp;
|
|
use core::fmt;
|
|
use core::hash;
|
|
use core::iter::RandomAccessIterator;
|
|
use core::iter::{Chain, Enumerate, Repeat, Skip, Take, repeat, Cloned};
|
|
use core::iter::{self, FromIterator};
|
|
use core::mem::swap;
|
|
use core::ops::Index;
|
|
use core::slice;
|
|
use core::{u8, u32, usize};
|
|
use bit_set; //so meta
|
|
|
|
use Vec;
|
|
|
|
type Blocks<'a> = Cloned<slice::Iter<'a, u32>>;
|
|
type MutBlocks<'a> = slice::IterMut<'a, u32>;
|
|
type MatchWords<'a> = Chain<Enumerate<Blocks<'a>>, Skip<Take<Enumerate<Repeat<u32>>>>>;
|
|
|
|
fn reverse_bits(byte: u8) -> u8 {
|
|
let mut result = 0;
|
|
for i in 0..u8::BITS {
|
|
result |= ((byte >> i) & 1) << (u8::BITS - 1 - i);
|
|
}
|
|
result
|
|
}
|
|
|
|
// 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>(a: &'a BitVec, b: &'b BitVec) -> (MatchWords<'a>, MatchWords<'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(0).enumerate().take(b_len).skip(a_len)),
|
|
b.blocks().enumerate().chain(iter::repeat(0).enumerate().take(0).skip(0)))
|
|
} else {
|
|
(a.blocks().enumerate().chain(iter::repeat(0).enumerate().take(0).skip(0)),
|
|
b.blocks().enumerate().chain(iter::repeat(0).enumerate().take(a_len).skip(b_len)))
|
|
}
|
|
}
|
|
|
|
static TRUE: bool = true;
|
|
static FALSE: bool = false;
|
|
|
|
/// The bitvector type.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let mut bv = BitVec::from_elem(10, false);
|
|
///
|
|
/// // insert all primes less than 10
|
|
/// bv.set(2, true);
|
|
/// bv.set(3, true);
|
|
/// bv.set(5, true);
|
|
/// bv.set(7, true);
|
|
/// println!("{:?}", bv);
|
|
/// println!("total bits set to true: {}", bv.iter().filter(|x| *x).count());
|
|
///
|
|
/// // flip all values in bitvector, producing non-primes less than 10
|
|
/// bv.negate();
|
|
/// println!("{:?}", bv);
|
|
/// println!("total bits set to true: {}", bv.iter().filter(|x| *x).count());
|
|
///
|
|
/// // reset bitvector to empty
|
|
/// bv.clear();
|
|
/// println!("{:?}", bv);
|
|
/// println!("total bits set to true: {}", bv.iter().filter(|x| *x).count());
|
|
/// ```
|
|
#[unstable(feature = "collections",
|
|
reason = "RFC 509")]
|
|
pub struct BitVec {
|
|
/// Internal representation of the bit vector
|
|
storage: Vec<u32>,
|
|
/// The number of valid bits in the internal representation
|
|
nbits: usize
|
|
}
|
|
|
|
// FIXME(Gankro): NopeNopeNopeNopeNope (wait for IndexGet to be a thing)
|
|
impl Index<usize> for BitVec {
|
|
type Output = bool;
|
|
|
|
#[inline]
|
|
fn index(&self, i: usize) -> &bool {
|
|
if self.get(i).expect("index out of bounds") {
|
|
&TRUE
|
|
} else {
|
|
&FALSE
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Computes how many blocks are needed to store that many bits
|
|
fn blocks_for_bits(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 + u32::BITS - 1) / 32::BITS`, but if nbits is almost usize::MAX this will overflow.
|
|
if bits % u32::BITS == 0 {
|
|
bits / u32::BITS
|
|
} else {
|
|
bits / u32::BITS + 1
|
|
}
|
|
}
|
|
|
|
/// Computes the bitmask for the final word of the vector
|
|
fn mask_for_bits(bits: usize) -> u32 {
|
|
// Note especially that a perfect multiple of u32::BITS should mask all 1s.
|
|
!0 >> (u32::BITS - bits % u32::BITS) % u32::BITS
|
|
}
|
|
|
|
impl BitVec {
|
|
/// Applies the given operation to the blocks of self and other, and sets
|
|
/// self to be the result. This relies on the caller not to corrupt the
|
|
/// last word.
|
|
#[inline]
|
|
fn process<F>(&mut self, other: &BitVec, mut op: F) -> bool where F: FnMut(u32, u32) -> u32 {
|
|
assert_eq!(self.len(), other.len());
|
|
// This could theoretically be a `debug_assert!`.
|
|
assert_eq!(self.storage.len(), other.storage.len());
|
|
let mut changed_bits = 0;
|
|
for (a, b) in self.blocks_mut().zip(other.blocks()) {
|
|
let w = op(*a, b);
|
|
changed_bits |= *a ^ w;
|
|
*a = w;
|
|
}
|
|
changed_bits != 0
|
|
}
|
|
|
|
/// Iterator over mutable refs to the underlying blocks of data.
|
|
fn blocks_mut(&mut self) -> MutBlocks {
|
|
// (2)
|
|
self.storage.iter_mut()
|
|
}
|
|
|
|
/// Iterator over the underlying blocks of data
|
|
fn blocks(&self) -> Blocks {
|
|
// (2)
|
|
self.storage.iter().cloned()
|
|
}
|
|
|
|
/// An operation might screw up the unused bits in the last block of the
|
|
/// `BitVec`. As per (3), it's assumed to be all 0s. This method fixes it up.
|
|
fn fix_last_block(&mut self) {
|
|
let extra_bits = self.len() % u32::BITS;
|
|
if extra_bits > 0 {
|
|
let mask = (1 << extra_bits) - 1;
|
|
let storage_len = self.storage.len();
|
|
self.storage[storage_len - 1] &= mask;
|
|
}
|
|
}
|
|
|
|
/// Creates an empty `BitVec`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
/// let mut bv = BitVec::new();
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn new() -> BitVec {
|
|
BitVec { storage: Vec::new(), nbits: 0 }
|
|
}
|
|
|
|
/// Creates a `BitVec` that holds `nbits` elements, setting each element
|
|
/// to `bit`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let mut bv = BitVec::from_elem(10, false);
|
|
/// assert_eq!(bv.len(), 10);
|
|
/// for x in bv.iter() {
|
|
/// assert_eq!(x, false);
|
|
/// }
|
|
/// ```
|
|
pub fn from_elem(nbits: usize, bit: bool) -> BitVec {
|
|
let nblocks = blocks_for_bits(nbits);
|
|
let mut bit_vec = BitVec {
|
|
storage: repeat(if bit { !0 } else { 0 }).take(nblocks).collect(),
|
|
nbits: nbits
|
|
};
|
|
bit_vec.fix_last_block();
|
|
bit_vec
|
|
}
|
|
|
|
/// Constructs a new, empty `BitVec` with the specified capacity.
|
|
///
|
|
/// The bitvector will be able to hold at least `capacity` bits without
|
|
/// reallocating. If `capacity` is 0, it will not allocate.
|
|
///
|
|
/// It is important to note that this function does not specify the
|
|
/// *length* of the returned bitvector, but only the *capacity*.
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn with_capacity(nbits: usize) -> BitVec {
|
|
BitVec {
|
|
storage: Vec::with_capacity(blocks_for_bits(nbits)),
|
|
nbits: 0,
|
|
}
|
|
}
|
|
|
|
/// Transforms a byte-vector into a `BitVec`. Each byte becomes eight bits,
|
|
/// with the most significant bits of each byte coming first. Each
|
|
/// bit becomes `true` if equal to 1 or `false` if equal to 0.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let bv = BitVec::from_bytes(&[0b10100000, 0b00010010]);
|
|
/// assert!(bv.eq_vec(&[true, false, true, false,
|
|
/// false, false, false, false,
|
|
/// false, false, false, true,
|
|
/// false, false, true, false]));
|
|
/// ```
|
|
pub fn from_bytes(bytes: &[u8]) -> BitVec {
|
|
let len = bytes.len().checked_mul(u8::BITS).expect("capacity overflow");
|
|
let mut bit_vec = BitVec::with_capacity(len);
|
|
let complete_words = bytes.len() / 4;
|
|
let extra_bytes = bytes.len() % 4;
|
|
|
|
bit_vec.nbits = len;
|
|
|
|
for i in 0..complete_words {
|
|
bit_vec.storage.push(
|
|
((reverse_bits(bytes[i * 4 + 0]) as u32) << 0) |
|
|
((reverse_bits(bytes[i * 4 + 1]) as u32) << 8) |
|
|
((reverse_bits(bytes[i * 4 + 2]) as u32) << 16) |
|
|
((reverse_bits(bytes[i * 4 + 3]) as u32) << 24)
|
|
);
|
|
}
|
|
|
|
if extra_bytes > 0 {
|
|
let mut last_word = 0;
|
|
for (i, &byte) in bytes[complete_words*4..].iter().enumerate() {
|
|
last_word |= (reverse_bits(byte) as u32) << (i * 8);
|
|
}
|
|
bit_vec.storage.push(last_word);
|
|
}
|
|
|
|
bit_vec
|
|
}
|
|
|
|
/// Creates a `BitVec` of the specified length where the value at each index
|
|
/// is `f(index)`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let bv = BitVec::from_fn(5, |i| { i % 2 == 0 });
|
|
/// assert!(bv.eq_vec(&[true, false, true, false, true]));
|
|
/// ```
|
|
pub fn from_fn<F>(len: usize, mut f: F) -> BitVec where F: FnMut(usize) -> bool {
|
|
let mut bit_vec = BitVec::from_elem(len, false);
|
|
for i in 0..len {
|
|
bit_vec.set(i, f(i));
|
|
}
|
|
bit_vec
|
|
}
|
|
|
|
/// Retrieves the value at index `i`, or `None` if the index is out of bounds.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let bv = BitVec::from_bytes(&[0b01100000]);
|
|
/// assert_eq!(bv.get(0), Some(false));
|
|
/// assert_eq!(bv.get(1), Some(true));
|
|
/// assert_eq!(bv.get(100), None);
|
|
///
|
|
/// // Can also use array indexing
|
|
/// assert_eq!(bv[1], true);
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn get(&self, i: usize) -> Option<bool> {
|
|
if i >= self.nbits {
|
|
return None;
|
|
}
|
|
let w = i / u32::BITS;
|
|
let b = i % u32::BITS;
|
|
self.storage.get(w).map(|&block|
|
|
(block & (1 << b)) != 0
|
|
)
|
|
}
|
|
|
|
/// Sets the value of a bit at an index `i`.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// Panics if `i` is out of bounds.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let mut bv = BitVec::from_elem(5, false);
|
|
/// bv.set(3, true);
|
|
/// assert_eq!(bv[3], true);
|
|
/// ```
|
|
#[inline]
|
|
#[unstable(feature = "collections",
|
|
reason = "panic semantics are likely to change in the future")]
|
|
pub fn set(&mut self, i: usize, x: bool) {
|
|
assert!(i < self.nbits);
|
|
let w = i / u32::BITS;
|
|
let b = i % u32::BITS;
|
|
let flag = 1 << b;
|
|
let val = if x { self.storage[w] | flag }
|
|
else { self.storage[w] & !flag };
|
|
self.storage[w] = val;
|
|
}
|
|
|
|
/// Sets all bits to 1.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let before = 0b01100000;
|
|
/// let after = 0b11111111;
|
|
///
|
|
/// let mut bv = BitVec::from_bytes(&[before]);
|
|
/// bv.set_all();
|
|
/// assert_eq!(bv, BitVec::from_bytes(&[after]));
|
|
/// ```
|
|
#[inline]
|
|
pub fn set_all(&mut self) {
|
|
for w in &mut self.storage { *w = !0; }
|
|
self.fix_last_block();
|
|
}
|
|
|
|
/// Flips all bits.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let before = 0b01100000;
|
|
/// let after = 0b10011111;
|
|
///
|
|
/// let mut bv = BitVec::from_bytes(&[before]);
|
|
/// bv.negate();
|
|
/// assert_eq!(bv, BitVec::from_bytes(&[after]));
|
|
/// ```
|
|
#[inline]
|
|
pub fn negate(&mut self) {
|
|
for w in &mut self.storage { *w = !*w; }
|
|
self.fix_last_block();
|
|
}
|
|
|
|
/// Calculates the union of two bitvectors. This acts like the bitwise `or`
|
|
/// function.
|
|
///
|
|
/// Sets `self` to the union of `self` and `other`. Both bitvectors must be
|
|
/// the same length. Returns `true` if `self` changed.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// Panics if the bitvectors are of different lengths.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let a = 0b01100100;
|
|
/// let b = 0b01011010;
|
|
/// let res = 0b01111110;
|
|
///
|
|
/// let mut a = BitVec::from_bytes(&[a]);
|
|
/// let b = BitVec::from_bytes(&[b]);
|
|
///
|
|
/// assert!(a.union(&b));
|
|
/// assert_eq!(a, BitVec::from_bytes(&[res]));
|
|
/// ```
|
|
#[inline]
|
|
pub fn union(&mut self, other: &BitVec) -> bool {
|
|
self.process(other, |w1, w2| w1 | w2)
|
|
}
|
|
|
|
/// Calculates the intersection of two bitvectors. This acts like the
|
|
/// bitwise `and` function.
|
|
///
|
|
/// Sets `self` to the intersection of `self` and `other`. Both bitvectors
|
|
/// must be the same length. Returns `true` if `self` changed.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// Panics if the bitvectors are of different lengths.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let a = 0b01100100;
|
|
/// let b = 0b01011010;
|
|
/// let res = 0b01000000;
|
|
///
|
|
/// let mut a = BitVec::from_bytes(&[a]);
|
|
/// let b = BitVec::from_bytes(&[b]);
|
|
///
|
|
/// assert!(a.intersect(&b));
|
|
/// assert_eq!(a, BitVec::from_bytes(&[res]));
|
|
/// ```
|
|
#[inline]
|
|
pub fn intersect(&mut self, other: &BitVec) -> bool {
|
|
self.process(other, |w1, w2| w1 & w2)
|
|
}
|
|
|
|
/// Calculates the difference between two bitvectors.
|
|
///
|
|
/// Sets each element of `self` to the value of that element minus the
|
|
/// element of `other` at the same index. Both bitvectors must be the same
|
|
/// length. Returns `true` if `self` changed.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// Panics if the bitvectors are of different length.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let a = 0b01100100;
|
|
/// let b = 0b01011010;
|
|
/// let a_b = 0b00100100; // a - b
|
|
/// let b_a = 0b00011010; // b - a
|
|
///
|
|
/// let mut bva = BitVec::from_bytes(&[a]);
|
|
/// let bvb = BitVec::from_bytes(&[b]);
|
|
///
|
|
/// assert!(bva.difference(&bvb));
|
|
/// assert_eq!(bva, BitVec::from_bytes(&[a_b]));
|
|
///
|
|
/// let bva = BitVec::from_bytes(&[a]);
|
|
/// let mut bvb = BitVec::from_bytes(&[b]);
|
|
///
|
|
/// assert!(bvb.difference(&bva));
|
|
/// assert_eq!(bvb, BitVec::from_bytes(&[b_a]));
|
|
/// ```
|
|
#[inline]
|
|
pub fn difference(&mut self, other: &BitVec) -> bool {
|
|
self.process(other, |w1, w2| w1 & !w2)
|
|
}
|
|
|
|
/// Returns `true` if all bits are 1.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let mut bv = BitVec::from_elem(5, true);
|
|
/// assert_eq!(bv.all(), true);
|
|
///
|
|
/// bv.set(1, false);
|
|
/// assert_eq!(bv.all(), false);
|
|
/// ```
|
|
pub fn all(&self) -> bool {
|
|
let mut last_word = !0;
|
|
// Check that every block but the last is all-ones...
|
|
self.blocks().all(|elem| {
|
|
let tmp = last_word;
|
|
last_word = elem;
|
|
tmp == !0
|
|
// and then check the last one has enough ones
|
|
}) && (last_word == mask_for_bits(self.nbits))
|
|
}
|
|
|
|
/// Returns an iterator over the elements of the vector in order.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let bv = BitVec::from_bytes(&[0b01110100, 0b10010010]);
|
|
/// assert_eq!(bv.iter().filter(|x| *x).count(), 7);
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn iter(&self) -> Iter {
|
|
Iter { bit_vec: self, next_idx: 0, end_idx: self.nbits }
|
|
}
|
|
|
|
/// Moves all bits from `other` into `Self`, leaving `other` empty.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections, bit_vec_append_split_off)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let mut a = BitVec::from_bytes(&[0b10000000]);
|
|
/// let mut b = BitVec::from_bytes(&[0b01100001]);
|
|
///
|
|
/// a.append(&mut b);
|
|
///
|
|
/// assert_eq!(a.len(), 16);
|
|
/// assert_eq!(b.len(), 0);
|
|
/// assert!(a.eq_vec(&[true, false, false, false, false, false, false, false,
|
|
/// false, true, true, false, false, false, false, true]));
|
|
/// ```
|
|
#[unstable(feature = "bit_vec_append_split_off",
|
|
reason = "recently added as part of collections reform 2")]
|
|
pub fn append(&mut self, other: &mut Self) {
|
|
let b = self.len() % u32::BITS;
|
|
|
|
self.nbits += other.len();
|
|
other.nbits = 0;
|
|
|
|
if b == 0 {
|
|
self.storage.append(&mut other.storage);
|
|
} else {
|
|
self.storage.reserve(other.storage.len());
|
|
|
|
for block in other.storage.drain(..) {
|
|
*(self.storage.last_mut().unwrap()) |= block << b;
|
|
self.storage.push(block >> (u32::BITS - b));
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Splits the `BitVec` into two at the given bit,
|
|
/// retaining the first half in-place and returning the second one.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// Panics if `at` is out of bounds.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections, bit_vec_append_split_off)]
|
|
/// use std::collections::BitVec;
|
|
/// let mut a = BitVec::new();
|
|
/// a.push(true);
|
|
/// a.push(false);
|
|
/// a.push(false);
|
|
/// a.push(true);
|
|
///
|
|
/// let b = a.split_off(2);
|
|
///
|
|
/// assert_eq!(a.len(), 2);
|
|
/// assert_eq!(b.len(), 2);
|
|
/// assert!(a.eq_vec(&[true, false]));
|
|
/// assert!(b.eq_vec(&[false, true]));
|
|
/// ```
|
|
#[unstable(feature = "bit_vec_append_split_off",
|
|
reason = "recently added as part of collections reform 2")]
|
|
pub fn split_off(&mut self, at: usize) -> Self {
|
|
assert!(at <= self.len(), "`at` out of bounds");
|
|
|
|
let mut other = BitVec::new();
|
|
|
|
if at == 0 {
|
|
swap(self, &mut other);
|
|
return other;
|
|
} else if at == self.len() {
|
|
return other;
|
|
}
|
|
|
|
let w = at / u32::BITS;
|
|
let b = at % u32::BITS;
|
|
other.nbits = self.nbits - at;
|
|
self.nbits = at;
|
|
if b == 0 {
|
|
// Split at block boundary
|
|
other.storage = self.storage.split_off(w);
|
|
} else {
|
|
other.storage.reserve(self.storage.len() - w);
|
|
|
|
{
|
|
let mut iter = self.storage[w..].iter();
|
|
let mut last = *iter.next().unwrap();
|
|
for &cur in iter {
|
|
other.storage.push((last >> b) | (cur << (u32::BITS - b)));
|
|
last = cur;
|
|
}
|
|
other.storage.push(last >> b);
|
|
}
|
|
|
|
self.storage.truncate(w+1);
|
|
self.fix_last_block();
|
|
}
|
|
|
|
other
|
|
}
|
|
|
|
/// Returns `true` if all bits are 0.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let mut bv = BitVec::from_elem(10, false);
|
|
/// assert_eq!(bv.none(), true);
|
|
///
|
|
/// bv.set(3, true);
|
|
/// assert_eq!(bv.none(), false);
|
|
/// ```
|
|
pub fn none(&self) -> bool {
|
|
self.blocks().all(|w| w == 0)
|
|
}
|
|
|
|
/// Returns `true` if any bit is 1.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let mut bv = BitVec::from_elem(10, false);
|
|
/// assert_eq!(bv.any(), false);
|
|
///
|
|
/// bv.set(3, true);
|
|
/// assert_eq!(bv.any(), true);
|
|
/// ```
|
|
#[inline]
|
|
pub fn any(&self) -> bool {
|
|
!self.none()
|
|
}
|
|
|
|
/// Organises the bits into bytes, such that the first bit in the
|
|
/// `BitVec` becomes the high-order bit of the first byte. If the
|
|
/// size of the `BitVec` is not a multiple of eight then trailing bits
|
|
/// will be filled-in with `false`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let mut bv = BitVec::from_elem(3, true);
|
|
/// bv.set(1, false);
|
|
///
|
|
/// assert_eq!(bv.to_bytes(), [0b10100000]);
|
|
///
|
|
/// let mut bv = BitVec::from_elem(9, false);
|
|
/// bv.set(2, true);
|
|
/// bv.set(8, true);
|
|
///
|
|
/// assert_eq!(bv.to_bytes(), [0b00100000, 0b10000000]);
|
|
/// ```
|
|
pub fn to_bytes(&self) -> Vec<u8> {
|
|
fn bit(bit_vec: &BitVec, byte: usize, bit: usize) -> u8 {
|
|
let offset = byte * 8 + bit;
|
|
if offset >= bit_vec.nbits {
|
|
0
|
|
} else {
|
|
(bit_vec[offset] as u8) << (7 - bit)
|
|
}
|
|
}
|
|
|
|
let len = self.nbits/8 +
|
|
if self.nbits % 8 == 0 { 0 } else { 1 };
|
|
(0..len).map(|i|
|
|
bit(self, i, 0) |
|
|
bit(self, i, 1) |
|
|
bit(self, i, 2) |
|
|
bit(self, i, 3) |
|
|
bit(self, i, 4) |
|
|
bit(self, i, 5) |
|
|
bit(self, i, 6) |
|
|
bit(self, i, 7)
|
|
).collect()
|
|
}
|
|
|
|
/// Compares a `BitVec` to a slice of `bool`s.
|
|
/// Both the `BitVec` and slice must have the same length.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// Panics if the `BitVec` and slice are of different length.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let bv = BitVec::from_bytes(&[0b10100000]);
|
|
///
|
|
/// assert!(bv.eq_vec(&[true, false, true, false,
|
|
/// false, false, false, false]));
|
|
/// ```
|
|
pub fn eq_vec(&self, v: &[bool]) -> bool {
|
|
assert_eq!(self.nbits, v.len());
|
|
iter::order::eq(self.iter(), v.iter().cloned())
|
|
}
|
|
|
|
/// Shortens a `BitVec`, dropping excess elements.
|
|
///
|
|
/// If `len` is greater than the vector's current length, this has no
|
|
/// effect.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let mut bv = BitVec::from_bytes(&[0b01001011]);
|
|
/// bv.truncate(2);
|
|
/// assert!(bv.eq_vec(&[false, true]));
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn truncate(&mut self, len: usize) {
|
|
if len < self.len() {
|
|
self.nbits = len;
|
|
// This fixes (2).
|
|
self.storage.truncate(blocks_for_bits(len));
|
|
self.fix_last_block();
|
|
}
|
|
}
|
|
|
|
/// Reserves capacity for at least `additional` more bits to be inserted in the given
|
|
/// `BitVec`. The collection may reserve more space to avoid frequent reallocations.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// Panics if the new capacity overflows `usize`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let mut bv = BitVec::from_elem(3, false);
|
|
/// bv.reserve(10);
|
|
/// assert_eq!(bv.len(), 3);
|
|
/// assert!(bv.capacity() >= 13);
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn reserve(&mut self, additional: usize) {
|
|
let desired_cap = self.len().checked_add(additional).expect("capacity overflow");
|
|
let storage_len = self.storage.len();
|
|
if desired_cap > self.capacity() {
|
|
self.storage.reserve(blocks_for_bits(desired_cap) - storage_len);
|
|
}
|
|
}
|
|
|
|
/// Reserves the minimum capacity for exactly `additional` more bits to be inserted in the
|
|
/// given `BitVec`. Does nothing if the capacity is already sufficient.
|
|
///
|
|
/// 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` if future
|
|
/// insertions are expected.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// Panics if the new capacity overflows `usize`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let mut bv = BitVec::from_elem(3, false);
|
|
/// bv.reserve(10);
|
|
/// assert_eq!(bv.len(), 3);
|
|
/// assert!(bv.capacity() >= 13);
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn reserve_exact(&mut self, additional: usize) {
|
|
let desired_cap = self.len().checked_add(additional).expect("capacity overflow");
|
|
let storage_len = self.storage.len();
|
|
if desired_cap > self.capacity() {
|
|
self.storage.reserve_exact(blocks_for_bits(desired_cap) - storage_len);
|
|
}
|
|
}
|
|
|
|
/// Returns the capacity in bits for this bit vector. Inserting any
|
|
/// element less than this amount will not trigger a resizing.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let mut bv = BitVec::new();
|
|
/// bv.reserve(10);
|
|
/// assert!(bv.capacity() >= 10);
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn capacity(&self) -> usize {
|
|
self.storage.capacity().checked_mul(u32::BITS).unwrap_or(usize::MAX)
|
|
}
|
|
|
|
/// Grows the `BitVec` in-place, adding `n` copies of `value` to the `BitVec`.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// Panics if the new len overflows a `usize`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let mut bv = BitVec::from_bytes(&[0b01001011]);
|
|
/// bv.grow(2, true);
|
|
/// assert_eq!(bv.len(), 10);
|
|
/// assert_eq!(bv.to_bytes(), [0b01001011, 0b11000000]);
|
|
/// ```
|
|
pub fn grow(&mut self, n: usize, value: bool) {
|
|
// Note: we just bulk set all the bits in the last word in this fn in multiple places
|
|
// which is technically wrong if not all of these bits are to be used. However, at the end
|
|
// of this fn we call `fix_last_block` at the end of this fn, which should fix this.
|
|
|
|
let new_nbits = self.nbits.checked_add(n).expect("capacity overflow");
|
|
let new_nblocks = blocks_for_bits(new_nbits);
|
|
let full_value = if value { !0 } else { 0 };
|
|
|
|
// Correct the old tail word, setting or clearing formerly unused bits
|
|
let num_cur_blocks = blocks_for_bits(self.nbits);
|
|
if self.nbits % u32::BITS > 0 {
|
|
let mask = mask_for_bits(self.nbits);
|
|
if value {
|
|
self.storage[num_cur_blocks - 1] |= !mask;
|
|
} else {
|
|
// Extra bits are already zero by invariant.
|
|
}
|
|
}
|
|
|
|
// Fill in words after the old tail word
|
|
let stop_idx = cmp::min(self.storage.len(), new_nblocks);
|
|
for idx in num_cur_blocks..stop_idx {
|
|
self.storage[idx] = full_value;
|
|
}
|
|
|
|
// Allocate new words, if needed
|
|
if new_nblocks > self.storage.len() {
|
|
let to_add = new_nblocks - self.storage.len();
|
|
self.storage.extend(repeat(full_value).take(to_add));
|
|
}
|
|
|
|
// Adjust internal bit count
|
|
self.nbits = new_nbits;
|
|
|
|
self.fix_last_block();
|
|
}
|
|
|
|
/// Removes the last bit from the BitVec, and returns it. Returns None if the BitVec is empty.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let mut bv = BitVec::from_bytes(&[0b01001001]);
|
|
/// assert_eq!(bv.pop(), Some(true));
|
|
/// assert_eq!(bv.pop(), Some(false));
|
|
/// assert_eq!(bv.len(), 6);
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn pop(&mut self) -> Option<bool> {
|
|
if self.is_empty() {
|
|
None
|
|
} else {
|
|
let i = self.nbits - 1;
|
|
let ret = self[i];
|
|
// (3)
|
|
self.set(i, false);
|
|
self.nbits = i;
|
|
if self.nbits % u32::BITS == 0 {
|
|
// (2)
|
|
self.storage.pop();
|
|
}
|
|
Some(ret)
|
|
}
|
|
}
|
|
|
|
/// Pushes a `bool` onto the end.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitVec;
|
|
///
|
|
/// let mut bv = BitVec::new();
|
|
/// bv.push(true);
|
|
/// bv.push(false);
|
|
/// assert!(bv.eq_vec(&[true, false]));
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn push(&mut self, elem: bool) {
|
|
if self.nbits % u32::BITS == 0 {
|
|
self.storage.push(0);
|
|
}
|
|
let insert_pos = self.nbits;
|
|
self.nbits = self.nbits.checked_add(1).expect("Capacity overflow");
|
|
self.set(insert_pos, elem);
|
|
}
|
|
|
|
/// Returns the total number of bits in this vector
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn len(&self) -> usize { self.nbits }
|
|
|
|
/// Returns true if there are no bits in this vector
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn is_empty(&self) -> bool { self.len() == 0 }
|
|
|
|
/// Clears all bits in this vector.
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn clear(&mut self) {
|
|
for w in &mut self.storage { *w = 0; }
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl Default for BitVec {
|
|
#[inline]
|
|
fn default() -> BitVec { BitVec::new() }
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl FromIterator<bool> for BitVec {
|
|
fn from_iter<I: IntoIterator<Item=bool>>(iter: I) -> BitVec {
|
|
let mut ret = BitVec::new();
|
|
ret.extend(iter);
|
|
ret
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl Extend<bool> for BitVec {
|
|
#[inline]
|
|
fn extend<I: IntoIterator<Item=bool>>(&mut self, iterable: I) {
|
|
let iterator = iterable.into_iter();
|
|
let (min, _) = iterator.size_hint();
|
|
self.reserve(min);
|
|
for element in iterator {
|
|
self.push(element)
|
|
}
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl Clone for BitVec {
|
|
#[inline]
|
|
fn clone(&self) -> BitVec {
|
|
BitVec { storage: self.storage.clone(), nbits: self.nbits }
|
|
}
|
|
|
|
#[inline]
|
|
fn clone_from(&mut self, source: &BitVec) {
|
|
self.nbits = source.nbits;
|
|
self.storage.clone_from(&source.storage);
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl PartialOrd for BitVec {
|
|
#[inline]
|
|
fn partial_cmp(&self, other: &BitVec) -> Option<Ordering> {
|
|
iter::order::partial_cmp(self.iter(), other.iter())
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl Ord for BitVec {
|
|
#[inline]
|
|
fn cmp(&self, other: &BitVec) -> Ordering {
|
|
iter::order::cmp(self.iter(), other.iter())
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl fmt::Debug for BitVec {
|
|
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
|
|
for bit in self {
|
|
try!(write!(fmt, "{}", if bit { 1 } else { 0 }));
|
|
}
|
|
Ok(())
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl hash::Hash for BitVec {
|
|
fn hash<H: hash::Hasher>(&self, state: &mut H) {
|
|
self.nbits.hash(state);
|
|
for elem in self.blocks() {
|
|
elem.hash(state);
|
|
}
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl cmp::PartialEq for BitVec {
|
|
#[inline]
|
|
fn eq(&self, other: &BitVec) -> bool {
|
|
if self.nbits != other.nbits {
|
|
return false;
|
|
}
|
|
self.blocks().zip(other.blocks()).all(|(w1, w2)| w1 == w2)
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl cmp::Eq for BitVec {}
|
|
|
|
/// An iterator for `BitVec`.
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[derive(Clone)]
|
|
pub struct Iter<'a> {
|
|
bit_vec: &'a BitVec,
|
|
next_idx: usize,
|
|
end_idx: usize,
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a> Iterator for Iter<'a> {
|
|
type Item = bool;
|
|
|
|
#[inline]
|
|
fn next(&mut self) -> Option<bool> {
|
|
if self.next_idx != self.end_idx {
|
|
let idx = self.next_idx;
|
|
self.next_idx += 1;
|
|
Some(self.bit_vec[idx])
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
let rem = self.end_idx - self.next_idx;
|
|
(rem, Some(rem))
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a> DoubleEndedIterator for Iter<'a> {
|
|
#[inline]
|
|
fn next_back(&mut self) -> Option<bool> {
|
|
if self.next_idx != self.end_idx {
|
|
self.end_idx -= 1;
|
|
Some(self.bit_vec[self.end_idx])
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a> ExactSizeIterator for Iter<'a> {}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a> RandomAccessIterator for Iter<'a> {
|
|
#[inline]
|
|
fn indexable(&self) -> usize {
|
|
self.end_idx - self.next_idx
|
|
}
|
|
|
|
#[inline]
|
|
fn idx(&mut self, index: usize) -> Option<bool> {
|
|
if index >= self.indexable() {
|
|
None
|
|
} else {
|
|
Some(self.bit_vec[index])
|
|
}
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a> IntoIterator for &'a BitVec {
|
|
type Item = bool;
|
|
type IntoIter = Iter<'a>;
|
|
|
|
fn into_iter(self) -> Iter<'a> {
|
|
self.iter()
|
|
}
|
|
}
|
|
|
|
/// 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
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::{BitSet, BitVec};
|
|
///
|
|
/// // 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_bit_vec(BitVec::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: BitVec = s.into_bit_vec();
|
|
/// assert!(bv[3]);
|
|
/// ```
|
|
#[derive(Clone)]
|
|
#[unstable(feature = "collections",
|
|
reason = "RFC 509")]
|
|
pub struct BitSet {
|
|
bit_vec: BitVec,
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl Default for BitSet {
|
|
#[inline]
|
|
fn default() -> BitSet { BitSet::new() }
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl FromIterator<usize> for BitSet {
|
|
fn from_iter<I: IntoIterator<Item=usize>>(iter: I) -> BitSet {
|
|
let mut ret = BitSet::new();
|
|
ret.extend(iter);
|
|
ret
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl Extend<usize> for BitSet {
|
|
#[inline]
|
|
fn extend<I: IntoIterator<Item=usize>>(&mut self, iter: I) {
|
|
for i in iter {
|
|
self.insert(i);
|
|
}
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl PartialOrd for BitSet {
|
|
#[inline]
|
|
fn partial_cmp(&self, other: &BitSet) -> Option<Ordering> {
|
|
let (a_iter, b_iter) = match_words(self.get_ref(), other.get_ref());
|
|
iter::order::partial_cmp(a_iter, b_iter)
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl Ord for BitSet {
|
|
#[inline]
|
|
fn cmp(&self, other: &BitSet) -> Ordering {
|
|
let (a_iter, b_iter) = match_words(self.get_ref(), other.get_ref());
|
|
iter::order::cmp(a_iter, b_iter)
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl cmp::PartialEq for BitSet {
|
|
#[inline]
|
|
fn eq(&self, other: &BitSet) -> bool {
|
|
let (a_iter, b_iter) = match_words(self.get_ref(), other.get_ref());
|
|
iter::order::eq(a_iter, b_iter)
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl cmp::Eq for BitSet {}
|
|
|
|
impl BitSet {
|
|
/// Creates a new empty `BitSet`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitSet;
|
|
///
|
|
/// let mut s = BitSet::new();
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn new() -> BitSet {
|
|
BitSet { bit_vec: BitVec::new() }
|
|
}
|
|
|
|
/// Creates a new `BitSet` with initially no contents, able to
|
|
/// hold `nbits` elements without resizing.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitSet;
|
|
///
|
|
/// let mut s = BitSet::with_capacity(100);
|
|
/// assert!(s.capacity() >= 100);
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn with_capacity(nbits: usize) -> BitSet {
|
|
let bit_vec = BitVec::from_elem(nbits, false);
|
|
BitSet::from_bit_vec(bit_vec)
|
|
}
|
|
|
|
/// Creates a new `BitSet` from the given bit vector.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::{BitVec, 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) -> BitSet {
|
|
BitSet { bit_vec: bit_vec }
|
|
}
|
|
|
|
/// Returns the capacity in bits for this bit vector. Inserting any
|
|
/// element less than this amount will not trigger a resizing.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitSet;
|
|
///
|
|
/// let mut s = BitSet::with_capacity(100);
|
|
/// assert!(s.capacity() >= 100);
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
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
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitSet;
|
|
///
|
|
/// let mut s = BitSet::new();
|
|
/// s.reserve_len(10);
|
|
/// assert!(s.capacity() >= 10);
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
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
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitSet;
|
|
///
|
|
/// let mut s = BitSet::new();
|
|
/// s.reserve_len_exact(10);
|
|
/// assert!(s.capacity() >= 10);
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
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
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::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 {
|
|
self.bit_vec
|
|
}
|
|
|
|
/// Returns a reference to the underlying bit vector.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitSet;
|
|
///
|
|
/// let mut s = BitSet::new();
|
|
/// s.insert(0);
|
|
///
|
|
/// let bv = s.get_ref();
|
|
/// assert_eq!(bv[0], true);
|
|
/// ```
|
|
#[inline]
|
|
pub fn get_ref(&self) -> &BitVec {
|
|
&self.bit_vec
|
|
}
|
|
|
|
#[inline]
|
|
fn other_op<F>(&mut self, other: &BitSet, mut f: F) where F: FnMut(u32, u32) -> u32 {
|
|
// 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);
|
|
self_bit_vec.storage[i] = new;
|
|
}
|
|
}
|
|
|
|
/// Truncates the underlying vector to the least length required.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::BitSet;
|
|
///
|
|
/// let mut s = BitSet::new();
|
|
/// s.insert(32183231);
|
|
/// s.remove(&32183231);
|
|
///
|
|
/// // Internal storage will probably be bigger than necessary
|
|
/// println!("old capacity: {}", s.capacity());
|
|
///
|
|
/// // Now should be smaller
|
|
/// s.shrink_to_fit();
|
|
/// println!("new capacity: {}", s.capacity());
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
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 == 0).count();
|
|
// Truncate
|
|
let trunc_len = cmp::max(old_len - n, 1);
|
|
bit_vec.storage.truncate(trunc_len);
|
|
bit_vec.nbits = trunc_len * u32::BITS;
|
|
}
|
|
|
|
/// Iterator over each usize stored in the `BitSet`.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::{BitVec, BitSet};
|
|
///
|
|
/// let s = BitSet::from_bit_vec(BitVec::from_bytes(&[0b01001010]));
|
|
///
|
|
/// // Print 1, 4, 6 in arbitrary order
|
|
/// for x in s.iter() {
|
|
/// println!("{}", x);
|
|
/// }
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn iter(&self) -> bit_set::Iter {
|
|
SetIter(BlockIter::from_blocks(self.bit_vec.blocks()))
|
|
}
|
|
|
|
/// Iterator over each usize stored in `self` union `other`.
|
|
/// See [union_with](#method.union_with) for an efficient in-place version.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::{BitVec, BitSet};
|
|
///
|
|
/// let a = BitSet::from_bit_vec(BitVec::from_bytes(&[0b01101000]));
|
|
/// let b = BitSet::from_bit_vec(BitVec::from_bytes(&[0b10100000]));
|
|
///
|
|
/// // Print 0, 1, 2, 4 in arbitrary order
|
|
/// for x in a.union(&b) {
|
|
/// println!("{}", x);
|
|
/// }
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn union<'a>(&'a self, other: &'a BitSet) -> Union<'a> {
|
|
fn or(w1: u32, w2: u32) -> u32 { 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](#method.intersect_with) for an efficient in-place version.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::{BitVec, BitSet};
|
|
///
|
|
/// let a = BitSet::from_bit_vec(BitVec::from_bytes(&[0b01101000]));
|
|
/// let b = BitSet::from_bit_vec(BitVec::from_bytes(&[0b10100000]));
|
|
///
|
|
/// // Print 2
|
|
/// for x in a.intersection(&b) {
|
|
/// println!("{}", x);
|
|
/// }
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn intersection<'a>(&'a self, other: &'a BitSet) -> Intersection<'a> {
|
|
fn bitand(w1: u32, w2: u32) -> u32 { w1 & w2 }
|
|
let min = cmp::min(self.bit_vec.len(), other.bit_vec.len());
|
|
|
|
Intersection(BlockIter::from_blocks(TwoBitPositions {
|
|
set: self.bit_vec.blocks(),
|
|
other: other.bit_vec.blocks(),
|
|
merge: bitand,
|
|
}).take(min))
|
|
}
|
|
|
|
/// Iterator over each usize stored in the `self` setminus `other`.
|
|
/// See [difference_with](#method.difference_with) for an efficient in-place version.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::{BitSet, BitVec};
|
|
///
|
|
/// let a = BitSet::from_bit_vec(BitVec::from_bytes(&[0b01101000]));
|
|
/// let b = BitSet::from_bit_vec(BitVec::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);
|
|
/// }
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn difference<'a>(&'a self, other: &'a BitSet) -> Difference<'a> {
|
|
fn diff(w1: u32, w2: u32) -> u32 { 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](#method.symmetric_difference_with) for
|
|
/// an efficient in-place version.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::{BitSet, BitVec};
|
|
///
|
|
/// let a = BitSet::from_bit_vec(BitVec::from_bytes(&[0b01101000]));
|
|
/// let b = BitSet::from_bit_vec(BitVec::from_bytes(&[0b10100000]));
|
|
///
|
|
/// // Print 0, 1, 4 in arbitrary order
|
|
/// for x in a.symmetric_difference(&b) {
|
|
/// println!("{}", x);
|
|
/// }
|
|
/// ```
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn symmetric_difference<'a>(&'a self, other: &'a BitSet) -> SymmetricDifference<'a> {
|
|
fn bitxor(w1: u32, w2: u32) -> u32 { 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
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::{BitSet, BitVec};
|
|
///
|
|
/// let a = 0b01101000;
|
|
/// let b = 0b10100000;
|
|
/// let res = 0b11101000;
|
|
///
|
|
/// let mut a = BitSet::from_bit_vec(BitVec::from_bytes(&[a]));
|
|
/// let b = BitSet::from_bit_vec(BitVec::from_bytes(&[b]));
|
|
/// let res = BitSet::from_bit_vec(BitVec::from_bytes(&[res]));
|
|
///
|
|
/// a.union_with(&b);
|
|
/// assert_eq!(a, res);
|
|
/// ```
|
|
#[inline]
|
|
pub fn union_with(&mut self, other: &BitSet) {
|
|
self.other_op(other, |w1, w2| w1 | w2);
|
|
}
|
|
|
|
/// Intersects in-place with the specified other bit vector.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::{BitSet, BitVec};
|
|
///
|
|
/// let a = 0b01101000;
|
|
/// let b = 0b10100000;
|
|
/// let res = 0b00100000;
|
|
///
|
|
/// let mut a = BitSet::from_bit_vec(BitVec::from_bytes(&[a]));
|
|
/// let b = BitSet::from_bit_vec(BitVec::from_bytes(&[b]));
|
|
/// let res = BitSet::from_bit_vec(BitVec::from_bytes(&[res]));
|
|
///
|
|
/// a.intersect_with(&b);
|
|
/// assert_eq!(a, res);
|
|
/// ```
|
|
#[inline]
|
|
pub fn intersect_with(&mut self, other: &BitSet) {
|
|
self.other_op(other, |w1, w2| w1 & w2);
|
|
}
|
|
|
|
/// Makes this bit vector the difference with the specified other bit vector
|
|
/// in-place.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::{BitSet, BitVec};
|
|
///
|
|
/// let a = 0b01101000;
|
|
/// let b = 0b10100000;
|
|
/// let a_b = 0b01001000; // a - b
|
|
/// let b_a = 0b10000000; // b - a
|
|
///
|
|
/// let mut bva = BitSet::from_bit_vec(BitVec::from_bytes(&[a]));
|
|
/// let bvb = BitSet::from_bit_vec(BitVec::from_bytes(&[b]));
|
|
/// let bva_b = BitSet::from_bit_vec(BitVec::from_bytes(&[a_b]));
|
|
/// let bvb_a = BitSet::from_bit_vec(BitVec::from_bytes(&[b_a]));
|
|
///
|
|
/// bva.difference_with(&bvb);
|
|
/// assert_eq!(bva, bva_b);
|
|
///
|
|
/// let bva = BitSet::from_bit_vec(BitVec::from_bytes(&[a]));
|
|
/// let mut bvb = BitSet::from_bit_vec(BitVec::from_bytes(&[b]));
|
|
///
|
|
/// bvb.difference_with(&bva);
|
|
/// assert_eq!(bvb, bvb_a);
|
|
/// ```
|
|
#[inline]
|
|
pub fn difference_with(&mut self, other: &BitSet) {
|
|
self.other_op(other, |w1, w2| w1 & !w2);
|
|
}
|
|
|
|
/// Makes this bit vector the symmetric difference with the specified other
|
|
/// bit vector in-place.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections)]
|
|
/// use std::collections::{BitSet, BitVec};
|
|
///
|
|
/// let a = 0b01101000;
|
|
/// let b = 0b10100000;
|
|
/// let res = 0b11001000;
|
|
///
|
|
/// let mut a = BitSet::from_bit_vec(BitVec::from_bytes(&[a]));
|
|
/// let b = BitSet::from_bit_vec(BitVec::from_bytes(&[b]));
|
|
/// let res = BitSet::from_bit_vec(BitVec::from_bytes(&[res]));
|
|
///
|
|
/// a.symmetric_difference_with(&b);
|
|
/// assert_eq!(a, res);
|
|
/// ```
|
|
#[inline]
|
|
pub fn symmetric_difference_with(&mut self, other: &BitSet) {
|
|
self.other_op(other, |w1, w2| w1 ^ w2);
|
|
}
|
|
|
|
/// Moves all elements from `other` into `Self`, leaving `other` empty.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections, bit_set_append_split_off)]
|
|
/// use std::collections::{BitVec, 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_bit_vec(BitVec::from_bytes(&[0b01110010])));
|
|
/// ```
|
|
#[unstable(feature = "bit_set_append_split_off",
|
|
reason = "recently added as part of collections reform 2")]
|
|
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
|
|
///
|
|
/// ```
|
|
/// # #![feature(collections, bit_set_append_split_off)]
|
|
/// use std::collections::{BitSet, BitVec};
|
|
/// 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_bit_vec(BitVec::from_bytes(&[0b01100000])));
|
|
/// assert_eq!(b, BitSet::from_bit_vec(BitVec::from_bytes(&[0b00010010])));
|
|
/// ```
|
|
#[unstable(feature = "bit_set_append_split_off",
|
|
reason = "recently added as part of collections reform 2")]
|
|
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 / u32::BITS;
|
|
let b = at % u32::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.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[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]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn len(&self) -> usize {
|
|
self.bit_vec.blocks().fold(0, |acc, n| acc + n.count_ones() as usize)
|
|
}
|
|
|
|
/// Returns whether there are no bits set in this set
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn is_empty(&self) -> bool {
|
|
self.bit_vec.none()
|
|
}
|
|
|
|
/// Clears all bits in this set
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn clear(&mut self) {
|
|
self.bit_vec.clear();
|
|
}
|
|
|
|
/// Returns `true` if this set contains the specified integer.
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn contains(&self, value: &usize) -> bool {
|
|
let bit_vec = &self.bit_vec;
|
|
*value < bit_vec.nbits && 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]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn is_disjoint(&self, other: &BitSet) -> bool {
|
|
self.intersection(other).next().is_none()
|
|
}
|
|
|
|
/// Returns `true` if the set is a subset of another.
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn is_subset(&self, other: &BitSet) -> bool {
|
|
let self_bit_vec = &self.bit_vec;
|
|
let other_bit_vec = &other.bit_vec;
|
|
let other_blocks = blocks_for_bits(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 == 0)
|
|
}
|
|
|
|
/// Returns `true` if the set is a superset of another.
|
|
#[inline]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn is_superset(&self, other: &BitSet) -> bool {
|
|
other.is_subset(self)
|
|
}
|
|
|
|
/// Adds a value to the set. Returns `true` if the value was not already
|
|
/// present in the set.
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
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);
|
|
return true;
|
|
}
|
|
|
|
/// Removes a value from the set. Returns `true` if the value was
|
|
/// present in the set.
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub fn remove(&mut self, value: &usize) -> bool {
|
|
if !self.contains(value) {
|
|
return false;
|
|
}
|
|
|
|
self.bit_vec.set(*value, false);
|
|
|
|
return true;
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl fmt::Debug for BitSet {
|
|
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
|
|
try!(write!(fmt, "{{"));
|
|
let mut first = true;
|
|
for n in self {
|
|
if !first {
|
|
try!(write!(fmt, ", "));
|
|
}
|
|
try!(write!(fmt, "{:?}", n));
|
|
first = false;
|
|
}
|
|
write!(fmt, "}}")
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl hash::Hash for BitSet {
|
|
fn hash<H: hash::Hasher>(&self, state: &mut H) {
|
|
for pos in self {
|
|
pos.hash(state);
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Clone)]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
struct BlockIter<T> where T: Iterator<Item=u32> {
|
|
head: u32,
|
|
head_offset: usize,
|
|
tail: T,
|
|
}
|
|
|
|
impl<'a, T> BlockIter<T> where T: Iterator<Item=u32> {
|
|
fn from_blocks(mut blocks: T) -> BlockIter<T> {
|
|
let h = blocks.next().unwrap_or(0);
|
|
BlockIter {tail: blocks, head: h, head_offset: 0}
|
|
}
|
|
}
|
|
|
|
/// An iterator combining two `BitSet` iterators.
|
|
#[derive(Clone)]
|
|
struct TwoBitPositions<'a> {
|
|
set: Blocks<'a>,
|
|
other: Blocks<'a>,
|
|
merge: fn(u32, u32) -> u32,
|
|
}
|
|
|
|
/// An iterator for `BitSet`.
|
|
#[derive(Clone)]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub struct SetIter<'a>(BlockIter<Blocks<'a>>);
|
|
#[derive(Clone)]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub struct Union<'a>(BlockIter<TwoBitPositions<'a>>);
|
|
#[derive(Clone)]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub struct Intersection<'a>(Take<BlockIter<TwoBitPositions<'a>>>);
|
|
#[derive(Clone)]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub struct Difference<'a>(BlockIter<TwoBitPositions<'a>>);
|
|
#[derive(Clone)]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
pub struct SymmetricDifference<'a>(BlockIter<TwoBitPositions<'a>>);
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, T> Iterator for BlockIter<T> where T: Iterator<Item=u32> {
|
|
type Item = usize;
|
|
|
|
fn next(&mut self) -> Option<usize> {
|
|
while self.head == 0 {
|
|
match self.tail.next() {
|
|
Some(w) => self.head = w,
|
|
None => return None
|
|
}
|
|
self.head_offset += u32::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 + 1)) - 1;
|
|
// update block, removing the LSB
|
|
self.head &= self.head - 1;
|
|
// return offset + (index of LSB)
|
|
Some(self.head_offset + (u32::count_ones(k) as usize))
|
|
}
|
|
|
|
#[inline]
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
match self.tail.size_hint() {
|
|
(_, Some(h)) => (0, Some(1 + h * (u32::BITS as usize))),
|
|
_ => (0, None)
|
|
}
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a> Iterator for TwoBitPositions<'a> {
|
|
type Item = u32;
|
|
|
|
fn next(&mut self) -> Option<u32> {
|
|
match (self.set.next(), self.other.next()) {
|
|
(Some(a), Some(b)) => Some((self.merge)(a, b)),
|
|
(Some(a), None) => Some((self.merge)(a, 0)),
|
|
(None, Some(b)) => Some((self.merge)(0, b)),
|
|
_ => return 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)
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a> Iterator for SetIter<'a> {
|
|
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() }
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a> Iterator for Union<'a> {
|
|
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() }
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a> Iterator for Intersection<'a> {
|
|
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() }
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a> Iterator for Difference<'a> {
|
|
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() }
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a> Iterator for SymmetricDifference<'a> {
|
|
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() }
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a> IntoIterator for &'a BitSet {
|
|
type Item = usize;
|
|
type IntoIter = SetIter<'a>;
|
|
|
|
fn into_iter(self) -> SetIter<'a> {
|
|
self.iter()
|
|
}
|
|
}
|