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143 lines
3.6 KiB
143 lines
3.6 KiB
// Copyright 2015 The Rust Project Developers. See the COPYRIGHT |
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// file at the top-level directory of this distribution and at |
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// http://rust-lang.org/COPYRIGHT. |
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// |
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
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// option. This file may not be copied, modified, or distributed |
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// except according to those terms. |
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// |
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// Original implementation taken from rust-memchr |
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// Copyright 2015 Andrew Gallant, bluss and Nicolas Koch |
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/// A safe interface to `memchr`. |
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/// |
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/// Returns the index corresponding to the first occurrence of `needle` in |
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/// `haystack`, or `None` if one is not found. |
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/// |
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/// memchr reduces to super-optimized machine code at around an order of |
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/// magnitude faster than `haystack.iter().position(|&b| b == needle)`. |
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/// (See benchmarks.) |
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/// |
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/// # Examples |
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/// |
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/// This shows how to find the first position of a byte in a byte string. |
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/// |
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/// ```ignore (cannot-doctest-private-modules) |
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/// use memchr::memchr; |
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/// |
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/// let haystack = b"the quick brown fox"; |
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/// assert_eq!(memchr(b'k', haystack), Some(8)); |
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/// ``` |
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#[inline] |
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pub fn memchr(needle: u8, haystack: &[u8]) -> Option<usize> { |
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::sys::memchr::memchr(needle, haystack) |
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} |
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/// A safe interface to `memrchr`. |
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/// |
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/// Returns the index corresponding to the last occurrence of `needle` in |
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/// `haystack`, or `None` if one is not found. |
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/// |
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/// # Examples |
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/// |
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/// This shows how to find the last position of a byte in a byte string. |
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/// |
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/// ```ignore (cannot-doctest-private-modules) |
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/// use memchr::memrchr; |
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/// |
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/// let haystack = b"the quick brown fox"; |
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/// assert_eq!(memrchr(b'o', haystack), Some(17)); |
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/// ``` |
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#[inline] |
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pub fn memrchr(needle: u8, haystack: &[u8]) -> Option<usize> { |
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::sys::memchr::memrchr(needle, haystack) |
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} |
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#[cfg(test)] |
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mod tests { |
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// test the implementations for the current plattform |
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use super::{memchr, memrchr}; |
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#[test] |
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fn matches_one() { |
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assert_eq!(Some(0), memchr(b'a', b"a")); |
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} |
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#[test] |
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fn matches_begin() { |
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assert_eq!(Some(0), memchr(b'a', b"aaaa")); |
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} |
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#[test] |
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fn matches_end() { |
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assert_eq!(Some(4), memchr(b'z', b"aaaaz")); |
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} |
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#[test] |
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fn matches_nul() { |
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assert_eq!(Some(4), memchr(b'\x00', b"aaaa\x00")); |
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} |
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#[test] |
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fn matches_past_nul() { |
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assert_eq!(Some(5), memchr(b'z', b"aaaa\x00z")); |
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} |
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#[test] |
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fn no_match_empty() { |
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assert_eq!(None, memchr(b'a', b"")); |
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} |
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#[test] |
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fn no_match() { |
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assert_eq!(None, memchr(b'a', b"xyz")); |
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} |
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#[test] |
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fn matches_one_reversed() { |
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assert_eq!(Some(0), memrchr(b'a', b"a")); |
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} |
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#[test] |
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fn matches_begin_reversed() { |
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assert_eq!(Some(3), memrchr(b'a', b"aaaa")); |
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} |
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#[test] |
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fn matches_end_reversed() { |
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assert_eq!(Some(0), memrchr(b'z', b"zaaaa")); |
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} |
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#[test] |
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fn matches_nul_reversed() { |
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assert_eq!(Some(4), memrchr(b'\x00', b"aaaa\x00")); |
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} |
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#[test] |
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fn matches_past_nul_reversed() { |
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assert_eq!(Some(0), memrchr(b'z', b"z\x00aaaa")); |
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} |
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#[test] |
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fn no_match_empty_reversed() { |
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assert_eq!(None, memrchr(b'a', b"")); |
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} |
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#[test] |
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fn no_match_reversed() { |
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assert_eq!(None, memrchr(b'a', b"xyz")); |
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} |
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#[test] |
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fn each_alignment() { |
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let mut data = [1u8; 64]; |
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let needle = 2; |
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let pos = 40; |
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data[pos] = needle; |
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for start in 0..16 { |
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assert_eq!(Some(pos - start), memchr(needle, &data[start..])); |
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} |
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} |
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}
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