max / goingson

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1	//! Shared text utilities for parsing and matching.
2
3	/// Case-insensitive prefix check without allocation.
4	///
5	/// Returns the remaining part of the string if `s` starts with `prefix`
6	/// (case-insensitive), otherwise returns `None`. Safe for multi-byte UTF-8.
7	pub fn strip_prefix_ci<'a>(s: &'a str, prefix: &str) -> Option<&'a str> {
8	if s.len() < prefix.len() \|\| !s.is_char_boundary(prefix.len()) {
9	return None;
10	}
11	let s_prefix = &s[..prefix.len()];
12	if s_prefix.eq_ignore_ascii_case(prefix) {
13	Some(&s[prefix.len()..])
14	} else {
15	None
16	}
17	}
18
19	#[cfg(test)]
20	mod tests {
21	use super::*;
22
23	#[test]
24	fn test_basic_match() {
25	assert_eq!(strip_prefix_ci("PROJECT:test", "project:"), Some("test"));
26	assert_eq!(strip_prefix_ci("Project:test", "project:"), Some("test"));
27	}
28
29	#[test]
30	fn test_no_match() {
31	assert_eq!(strip_prefix_ci("proj:test", "project:"), None);
32	assert_eq!(strip_prefix_ci("pr", "project:"), None);
33	}
34
35	#[test]
36	fn test_multibyte_utf8_safe() {
37	// Ensure no panic on multi-byte characters near prefix boundary
38	assert_eq!(strip_prefix_ci("pr😀:H", "pri:"), None);
39	assert_eq!(strip_prefix_ci("düe:tom", "due:"), None);
40	}
41	}
42