Struct BitParallelSearcher 

pub struct BitParallelSearcher { /* private fields */ }

Pre-computed searcher for a specific pattern.

Creating the searcher has O(m) setup cost where m is pattern length. Reuse the searcher across multiple texts to amortize this cost.

Implementation Details

Uses the Shift-Or algorithm (also known as Baeza-Yates–Gonnet algorithm). Each bit in a u64 represents whether the pattern matches up to that position.

Implementations

impl BitParallelSearcher

pub fn new(pattern: &[u8]) -> Self

Create a new searcher for the given pattern.

Performance

• Setup: O(m) where m = pattern.len()
• Memory: 2KB (256 * 8 bytes for mask table)

Panics

Panics if pattern is empty.

Example

use bit_parallel_search::BitParallelSearcher;

let searcher = BitParallelSearcher::new(b"pattern");

pub fn find_in(&self, text: &[u8]) -> Option<usize>

Search for the pattern in the given text.

Performance

• Time: O(n) where n = text.len()
• Memory: O(1)

Returns

Position of first match, or None if pattern not found.

Example

use bit_parallel_search::BitParallelSearcher;

let searcher = BitParallelSearcher::new(b"fox");
let text = b"The quick brown fox";
assert_eq!(searcher.find_in(text), Some(16));

pub fn find_all_in<'t>( &self, text: &'t [u8], ) -> impl Iterator<Item = usize> + 't

Available on crate feature std only.

Find all occurrences of the pattern in text.

Performance

Same as find_in but continues searching after each match.

Example

use bit_parallel_search::BitParallelSearcher;

let searcher = BitParallelSearcher::new(b"ab");
let text = b"ababab";
let matches: Vec<_> = searcher.find_all_in(text).collect();
assert_eq!(matches, vec![0, 2, 4]);

pub fn count_in(&self, text: &[u8]) -> usize

Count occurrences without collecting positions.

More efficient than find_all_in().count() as it avoids iterator overhead.

Example

use bit_parallel_search::BitParallelSearcher;

let searcher = BitParallelSearcher::new(b"ab");
assert_eq!(searcher.count_in(b"ababab"), 3);

pub fn exists_in(&self, text: &[u8]) -> bool

Returns true if pattern exists in text.

Equivalent to find_in(text).is_some() but may be slightly faster.

pub fn pattern_len(&self) -> usize

Get the pattern length.

Trait Implementations

impl Clone for BitParallelSearcher

fn clone(&self) -> BitParallelSearcher

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for BitParallelSearcher

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

Formats the value using the given formatter.

impl Send for BitParallelSearcher

impl Sync for BitParallelSearcher