| // |
| // Original implementation taken from rust-memchr |
| // Copyright 2015 Andrew Gallant, bluss and Nicolas Koch |
| |
| /// A safe interface to `memchr`. |
| /// |
| /// Returns the index corresponding to the first occurrence of `needle` in |
| /// `haystack`, or `None` if one is not found. |
| /// |
| /// memchr reduces to super-optimized machine code at around an order of |
| /// magnitude faster than `haystack.iter().position(|&b| b == needle)`. |
| /// (See benchmarks.) |
| /// |
| /// # Examples |
| /// |
| /// This shows how to find the first position of a byte in a byte string. |
| /// |
| /// ```ignore (cannot-doctest-private-modules) |
| /// use memchr::memchr; |
| /// |
| /// let haystack = b"the quick brown fox"; |
| /// assert_eq!(memchr(b'k', haystack), Some(8)); |
| /// ``` |
| #[inline] |
| pub fn memchr(needle: u8, haystack: &[u8]) -> Option<usize> { |
| ::sys::memchr::memchr(needle, haystack) |
| } |
| |
| /// A safe interface to `memrchr`. |
| /// |
| /// Returns the index corresponding to the last occurrence of `needle` in |
| /// `haystack`, or `None` if one is not found. |
| /// |
| /// # Examples |
| /// |
| /// This shows how to find the last position of a byte in a byte string. |
| /// |
| /// ```ignore (cannot-doctest-private-modules) |
| /// use memchr::memrchr; |
| /// |
| /// let haystack = b"the quick brown fox"; |
| /// assert_eq!(memrchr(b'o', haystack), Some(17)); |
| /// ``` |
| #[inline] |
| pub fn memrchr(needle: u8, haystack: &[u8]) -> Option<usize> { |
| ::sys::memchr::memrchr(needle, haystack) |
| } |
| |
| #[cfg(test)] |
| mod tests { |
| // test the implementations for the current platform |
| use super::{memchr, memrchr}; |
| |
| #[test] |
| fn matches_one() { |
| assert_eq!(Some(0), memchr(b'a', b"a")); |
| } |
| |
| #[test] |
| fn matches_begin() { |
| assert_eq!(Some(0), memchr(b'a', b"aaaa")); |
| } |
| |
| #[test] |
| fn matches_end() { |
| assert_eq!(Some(4), memchr(b'z', b"aaaaz")); |
| } |
| |
| #[test] |
| fn matches_nul() { |
| assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00")); |
| } |
| |
| #[test] |
| fn matches_past_nul() { |
| assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z")); |
| } |
| |
| #[test] |
| fn no_match_empty() { |
| assert_eq!(None, memchr(b'a', b"")); |
| } |
| |
| #[test] |
| fn no_match() { |
| assert_eq!(None, memchr(b'a', b"xyz")); |
| } |
| |
| #[test] |
| fn matches_one_reversed() { |
| assert_eq!(Some(0), memrchr(b'a', b"a")); |
| } |
| |
| #[test] |
| fn matches_begin_reversed() { |
| assert_eq!(Some(3), memrchr(b'a', b"aaaa")); |
| } |
| |
| #[test] |
| fn matches_end_reversed() { |
| assert_eq!(Some(0), memrchr(b'z', b"zaaaa")); |
| } |
| |
| #[test] |
| fn matches_nul_reversed() { |
| assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00")); |
| } |
| |
| #[test] |
| fn matches_past_nul_reversed() { |
| assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa")); |
| } |
| |
| #[test] |
| fn no_match_empty_reversed() { |
| assert_eq!(None, memrchr(b'a', b"")); |
| } |
| |
| #[test] |
| fn no_match_reversed() { |
| assert_eq!(None, memrchr(b'a', b"xyz")); |
| } |
| |
| #[test] |
| fn each_alignment() { |
| let mut data = [1u8; 64]; |
| let needle = 2; |
| let pos = 40; |
| data[pos] = needle; |
| for start in 0..16 { |
| assert_eq!(Some(pos - start), memchr(needle, &data[start..])); |
| } |
| } |
| } |