Struct fid::bit_vector::BitVector

pub struct BitVector { /* fields omitted */ }

A succinct bit vector that supports FID operations (rank and select) in constant time.

Bits are divided in small and large blocks. Each small block is identified by a class (number of 1s in the block) and an index within the class. Classes are stored in ceil(log(SBLOCK_WIDTH + 1)) bits. Indices are stored in log(C(SBLOCK_WIDTH, index)) bits with enumerative code if its compressed size is less than MAX_CODE_SIZE. Otherwise the bit pattern of the small block is explicitly stored as an index for the sake of efficiency. This idea originally comes from [2]. For each large block, we store the number of 1s up to its beginning and a pointer for the index of the first small block.

Examples

use fid::{BitVector, FID};
let mut bv = BitVector::new();
bv.push(false); bv.push(true); bv.push(true); bv.push(false);
bv.push(true); bv.push(true); bv.push(false); bv.push(true);

assert_eq!(bv.rank0(5), 2);
assert_eq!(bv.rank1(5), 3);
assert_eq!(bv.select0(2), 6);
assert_eq!(bv.select1(2), 4);

References

[1] Gonzalo Navarro and Eliana Providel. 2012. Fast, small, simple rank/select on bitmaps. In Proceedings of the 11th international conference on Experimental Algorithms (SEA'12), Ralf Klasing (Ed.). Springer-Verlag, Berlin, Heidelberg, 295-306. DOI=http://dx.doi.org/10.1007/978-3-642-30850-5_26

[2] rsdic by Daisuke Okanohara. https://github.com/hillbig/rsdic

Methods

impl BitVector

pub fn new() -> Self

pub fn push(&mut self, b: bool)

Appends a bit at the end of the vector.

Trait Implementations

impl Debug for BitVector

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.

impl FID for BitVector

fn len(&self) -> u64

Returns the total number of bits.

fn rank1(&self, i: u64) -> u64

Compute the number of 0s in [0..i).

fn select1(&self, r: u64) -> u64

Locate the position of the (r + 1)-th 1.

fn select0(&self, r: u64) -> u64

Locate the position of the (r + 1)-th 0.

fn rank(&self, b: bool, i: u64) -> u64

Compute the number of bits in [0..i).

fn rank0(&self, i: u64) -> u64

Compute the number of 0s in [0..i).

fn select(&self, b: bool, r: u64) -> u64

Locate the position of the (r + 1)-th bit.