55 lines
1.8 KiB
Rust
55 lines
1.8 KiB
Rust
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//! Small allocation-free text predicates shared across the hot parse paths.
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/// ASCII case-insensitive substring test — the allocation-free equivalent of
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/// `haystack_lower.contains(needle_lower)` when both are ASCII.
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///
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/// Callers pass an already-upper/lower-cased `needle` and get the same boolean
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/// `haystack.to_ascii_uppercase().contains(NEEDLE)` would, without the
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/// throwaway per-call `String`. Used by the search name-match classifier and by
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/// `ContactService::parse_vcard`'s per-line `TYPE=` routing
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/// (benches/ROUND20.md §A3).
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pub fn ascii_ci_contains(haystack: &[u8], needle: &[u8]) -> bool {
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if needle.is_empty() {
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return true;
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}
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if needle.len() > haystack.len() {
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return false;
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}
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haystack
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.windows(needle.len())
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.any(|w| w.eq_ignore_ascii_case(needle))
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn matches_uppercase_contains() {
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// Parity with the `to_ascii_uppercase().contains(NEEDLE)` shape it
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// replaced, across mixed case and the empty/oversize edge cases.
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let cases: &[(&str, &str)] = &[
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("EMAIL;TYPE=home:a@b.com", "TYPE=HOME"),
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("EMAIL;type=Work:a@b.com", "TYPE=WORK"),
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("TEL;TYPE=CELL:+1", "TYPE=CELL"),
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("TEL;TYPE=voice:+1", "TYPE=CELL"),
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("ADR;TYPE=Home:;;x", "TYPE=WORK"),
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("", "TYPE=HOME"),
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("short", "a-very-long-needle"),
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];
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for (hay, needle) in cases {
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let reference = hay.to_ascii_uppercase().contains(needle);
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assert_eq!(
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ascii_ci_contains(hay.as_bytes(), needle.as_bytes()),
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reference,
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"mismatch for haystack={hay:?} needle={needle:?}"
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);
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}
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}
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#[test]
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fn empty_needle_is_true() {
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assert!(ascii_ci_contains(b"anything", b""));
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}
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}
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