Sha256: df6f55d165382b8a53762ba4c324926cac13ebc62cde1805f4ce08740b326483
Contents?: true
Size: 1.2 KB
Versions: 23
Compression:
Stored size: 1.2 KB
Contents
/*!
This module defines "naive" implementations of substring search.
These are sometimes useful to compare with "real" substring implementations.
The idea is that they are so simple that they are unlikely to be incorrect.
*/
/// Naively search forwards for the given needle in the given haystack.
pub(crate) fn find(haystack: &[u8], needle: &[u8]) -> Option<usize> {
let end = haystack.len().checked_sub(needle.len()).map_or(0, |i| i + 1);
for i in 0..end {
if needle == &haystack[i..i + needle.len()] {
return Some(i);
}
}
None
}
/// Naively search in reverse for the given needle in the given haystack.
pub(crate) fn rfind(haystack: &[u8], needle: &[u8]) -> Option<usize> {
let end = haystack.len().checked_sub(needle.len()).map_or(0, |i| i + 1);
for i in (0..end).rev() {
if needle == &haystack[i..i + needle.len()] {
return Some(i);
}
}
None
}
#[cfg(test)]
mod tests {
use crate::tests::substring;
use super::*;
#[test]
fn forward() {
substring::Runner::new().fwd(|h, n| Some(find(h, n))).run()
}
#[test]
fn reverse() {
substring::Runner::new().rev(|h, n| Some(rfind(h, n))).run()
}
}
Version data entries
23 entries across 23 versions & 1 rubygems