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Diffstat (limited to 'vendor/memchr/src/tests/substring/naive.rs')
-rw-r--r-- | vendor/memchr/src/tests/substring/naive.rs | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/vendor/memchr/src/tests/substring/naive.rs b/vendor/memchr/src/tests/substring/naive.rs new file mode 100644 index 000000000..1bc600984 --- /dev/null +++ b/vendor/memchr/src/tests/substring/naive.rs @@ -0,0 +1,45 @@ +/*! +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() + } +} |