| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `/root/.cargo/registry/src/github.com-1ecc6299db9ec823/memchr-2.5.0/src/memmem/mod.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>mod.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../../normalize.css"><link rel="stylesheet" href="../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../../ayu.css" disabled><link rel="stylesheet" href="../../../dark.css" disabled><link rel="stylesheet" href="../../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../../storage.js"></script><script defer src="../../../source-script.js"></script><script defer src="../../../source-files.js"></script><script defer src="../../../main.js"></script><noscript><link rel="stylesheet" href="../../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../../memchr/index.html"><div class="logo-container"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../../memchr/index.html"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><span id="1">1</span> |
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| <span id="1102">1102</span> |
| <span id="1103">1103</span> |
| <span id="1104">1104</span> |
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| <span id="1301">1301</span> |
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| <span id="1310">1310</span> |
| <span id="1311">1311</span> |
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| <span id="1317">1317</span> |
| <span id="1318">1318</span> |
| <span id="1319">1319</span> |
| <span id="1320">1320</span> |
| <span id="1321">1321</span> |
| </pre><pre class="rust"><code><span class="doccomment">/*! |
| This module provides forward and reverse substring search routines. |
| |
| Unlike the standard library's substring search routines, these work on |
| arbitrary bytes. For all non-empty needles, these routines will report exactly |
| the same values as the corresponding routines in the standard library. For |
| the empty needle, the standard library reports matches only at valid UTF-8 |
| boundaries, where as these routines will report matches at every position. |
| |
| Other than being able to work on arbitrary bytes, the primary reason to prefer |
| these routines over the standard library routines is that these will generally |
| be faster. In some cases, significantly so. |
| |
| # Example: iterating over substring matches |
| |
| This example shows how to use [`find_iter`] to find occurrences of a substring |
| in a haystack. |
| |
| ``` |
| use memchr::memmem; |
| |
| let haystack = b"foo bar foo baz foo"; |
| |
| let mut it = memmem::find_iter(haystack, "foo"); |
| assert_eq!(Some(0), it.next()); |
| assert_eq!(Some(8), it.next()); |
| assert_eq!(Some(16), it.next()); |
| assert_eq!(None, it.next()); |
| ``` |
| |
| # Example: iterating over substring matches in reverse |
| |
| This example shows how to use [`rfind_iter`] to find occurrences of a substring |
| in a haystack starting from the end of the haystack. |
| |
| **NOTE:** This module does not implement double ended iterators, so reverse |
| searches aren't done by calling `rev` on a forward iterator. |
| |
| ``` |
| use memchr::memmem; |
| |
| let haystack = b"foo bar foo baz foo"; |
| |
| let mut it = memmem::rfind_iter(haystack, "foo"); |
| assert_eq!(Some(16), it.next()); |
| assert_eq!(Some(8), it.next()); |
| assert_eq!(Some(0), it.next()); |
| assert_eq!(None, it.next()); |
| ``` |
| |
| # Example: repeating a search for the same needle |
| |
| It may be possible for the overhead of constructing a substring searcher to be |
| measurable in some workloads. In cases where the same needle is used to search |
| many haystacks, it is possible to do construction once and thus to avoid it for |
| subsequent searches. This can be done with a [`Finder`] (or a [`FinderRev`] for |
| reverse searches). |
| |
| ``` |
| use memchr::memmem; |
| |
| let finder = memmem::Finder::new("foo"); |
| |
| assert_eq!(Some(4), finder.find(b"baz foo quux")); |
| assert_eq!(None, finder.find(b"quux baz bar")); |
| ``` |
| */ |
| |
| </span><span class="kw">pub use </span><span class="self">self</span>::prefilter::Prefilter; |
| |
| <span class="kw">use crate</span>::{ |
| cow::CowBytes, |
| memmem::{ |
| prefilter::{Pre, PrefilterFn, PrefilterState}, |
| rabinkarp::NeedleHash, |
| rarebytes::RareNeedleBytes, |
| }, |
| }; |
| |
| <span class="doccomment">/// Defines a suite of quickcheck properties for forward and reverse |
| /// substring searching. |
| /// |
| /// This is defined in this specific spot so that it can be used freely among |
| /// the different substring search implementations. I couldn't be bothered to |
| /// fight with the macro-visibility rules enough to figure out how to stuff it |
| /// somewhere more convenient. |
| </span><span class="attribute">#[cfg(all(test, feature = <span class="string">"std"</span>))] |
| </span><span class="macro">macro_rules! </span>define_memmem_quickcheck_tests { |
| (<span class="macro-nonterminal">$fwd</span>:expr, <span class="macro-nonterminal">$rev</span>:expr) => { |
| <span class="kw">use </span><span class="kw">crate</span>::memmem::proptests; |
| |
| <span class="macro">quickcheck::quickcheck! </span>{ |
| <span class="kw">fn </span>qc_fwd_prefix_is_substring(bs: Vec<u8>) -> bool { |
| proptests::prefix_is_substring(<span class="bool-val">false</span>, <span class="kw-2">&</span>bs, <span class="macro-nonterminal">$fwd</span>) |
| } |
| |
| <span class="kw">fn </span>qc_fwd_suffix_is_substring(bs: Vec<u8>) -> bool { |
| proptests::suffix_is_substring(<span class="bool-val">false</span>, <span class="kw-2">&</span>bs, <span class="macro-nonterminal">$fwd</span>) |
| } |
| |
| <span class="kw">fn </span>qc_fwd_matches_naive( |
| haystack: Vec<u8>, |
| needle: Vec<u8> |
| ) -> bool { |
| proptests::matches_naive(<span class="bool-val">false</span>, <span class="kw-2">&</span>haystack, <span class="kw-2">&</span>needle, <span class="macro-nonterminal">$fwd</span>) |
| } |
| |
| <span class="kw">fn </span>qc_rev_prefix_is_substring(bs: Vec<u8>) -> bool { |
| proptests::prefix_is_substring(<span class="bool-val">true</span>, <span class="kw-2">&</span>bs, <span class="macro-nonterminal">$rev</span>) |
| } |
| |
| <span class="kw">fn </span>qc_rev_suffix_is_substring(bs: Vec<u8>) -> bool { |
| proptests::suffix_is_substring(<span class="bool-val">true</span>, <span class="kw-2">&</span>bs, <span class="macro-nonterminal">$rev</span>) |
| } |
| |
| <span class="kw">fn </span>qc_rev_matches_naive( |
| haystack: Vec<u8>, |
| needle: Vec<u8> |
| ) -> bool { |
| proptests::matches_naive(<span class="bool-val">true</span>, <span class="kw-2">&</span>haystack, <span class="kw-2">&</span>needle, <span class="macro-nonterminal">$rev</span>) |
| } |
| } |
| }; |
| } |
| |
| <span class="doccomment">/// Defines a suite of "simple" hand-written tests for a substring |
| /// implementation. |
| /// |
| /// This is defined here for the same reason that |
| /// define_memmem_quickcheck_tests is defined here. |
| </span><span class="attribute">#[cfg(test)] |
| </span><span class="macro">macro_rules! </span>define_memmem_simple_tests { |
| (<span class="macro-nonterminal">$fwd</span>:expr, <span class="macro-nonterminal">$rev</span>:expr) => { |
| <span class="kw">use </span><span class="kw">crate</span>::memmem::testsimples; |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>simple_forward() { |
| testsimples::run_search_tests_fwd(<span class="macro-nonterminal">$fwd</span>); |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>simple_reverse() { |
| testsimples::run_search_tests_rev(<span class="macro-nonterminal">$rev</span>); |
| } |
| }; |
| } |
| |
| <span class="kw">mod </span>byte_frequencies; |
| <span class="attribute">#[cfg(memchr_runtime_simd)] |
| </span><span class="kw">mod </span>genericsimd; |
| <span class="kw">mod </span>prefilter; |
| <span class="kw">mod </span>rabinkarp; |
| <span class="kw">mod </span>rarebytes; |
| <span class="kw">mod </span>twoway; |
| <span class="kw">mod </span>util; |
| <span class="attribute">#[cfg(memchr_runtime_simd)] |
| </span><span class="kw">mod </span>vector; |
| <span class="attribute">#[cfg(all(memchr_runtime_wasm128))] |
| </span><span class="kw">mod </span>wasm; |
| <span class="attribute">#[cfg(all(not(miri), target_arch = <span class="string">"x86_64"</span>, memchr_runtime_simd))] |
| </span><span class="kw">mod </span>x86; |
| |
| <span class="doccomment">/// Returns an iterator over all non-overlapping occurrences of a substring in |
| /// a haystack. |
| /// |
| /// # Complexity |
| /// |
| /// This routine is guaranteed to have worst case linear time complexity |
| /// with respect to both the needle and the haystack. That is, this runs |
| /// in `O(needle.len() + haystack.len())` time. |
| /// |
| /// This routine is also guaranteed to have worst case constant space |
| /// complexity. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// use memchr::memmem; |
| /// |
| /// let haystack = b"foo bar foo baz foo"; |
| /// let mut it = memmem::find_iter(haystack, b"foo"); |
| /// assert_eq!(Some(0), it.next()); |
| /// assert_eq!(Some(8), it.next()); |
| /// assert_eq!(Some(16), it.next()); |
| /// assert_eq!(None, it.next()); |
| /// ``` |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>find_iter<<span class="lifetime">'h</span>, <span class="lifetime">'n</span>, N: <span class="lifetime">'n </span>+ <span class="question-mark">?</span>Sized + AsRef<[u8]>>( |
| haystack: <span class="kw-2">&</span><span class="lifetime">'h </span>[u8], |
| needle: <span class="kw-2">&</span><span class="lifetime">'n </span>N, |
| ) -> FindIter<<span class="lifetime">'h</span>, <span class="lifetime">'n</span>> { |
| FindIter::new(haystack, Finder::new(needle)) |
| } |
| |
| <span class="doccomment">/// Returns a reverse iterator over all non-overlapping occurrences of a |
| /// substring in a haystack. |
| /// |
| /// # Complexity |
| /// |
| /// This routine is guaranteed to have worst case linear time complexity |
| /// with respect to both the needle and the haystack. That is, this runs |
| /// in `O(needle.len() + haystack.len())` time. |
| /// |
| /// This routine is also guaranteed to have worst case constant space |
| /// complexity. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// use memchr::memmem; |
| /// |
| /// let haystack = b"foo bar foo baz foo"; |
| /// let mut it = memmem::rfind_iter(haystack, b"foo"); |
| /// assert_eq!(Some(16), it.next()); |
| /// assert_eq!(Some(8), it.next()); |
| /// assert_eq!(Some(0), it.next()); |
| /// assert_eq!(None, it.next()); |
| /// ``` |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>rfind_iter<<span class="lifetime">'h</span>, <span class="lifetime">'n</span>, N: <span class="lifetime">'n </span>+ <span class="question-mark">?</span>Sized + AsRef<[u8]>>( |
| haystack: <span class="kw-2">&</span><span class="lifetime">'h </span>[u8], |
| needle: <span class="kw-2">&</span><span class="lifetime">'n </span>N, |
| ) -> FindRevIter<<span class="lifetime">'h</span>, <span class="lifetime">'n</span>> { |
| FindRevIter::new(haystack, FinderRev::new(needle)) |
| } |
| |
| <span class="doccomment">/// Returns the index of the first occurrence of the given needle. |
| /// |
| /// Note that if you're are searching for the same needle in many different |
| /// small haystacks, it may be faster to initialize a [`Finder`] once, |
| /// and reuse it for each search. |
| /// |
| /// # Complexity |
| /// |
| /// This routine is guaranteed to have worst case linear time complexity |
| /// with respect to both the needle and the haystack. That is, this runs |
| /// in `O(needle.len() + haystack.len())` time. |
| /// |
| /// This routine is also guaranteed to have worst case constant space |
| /// complexity. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// use memchr::memmem; |
| /// |
| /// let haystack = b"foo bar baz"; |
| /// assert_eq!(Some(0), memmem::find(haystack, b"foo")); |
| /// assert_eq!(Some(4), memmem::find(haystack, b"bar")); |
| /// assert_eq!(None, memmem::find(haystack, b"quux")); |
| /// ``` |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>find(haystack: <span class="kw-2">&</span>[u8], needle: <span class="kw-2">&</span>[u8]) -> <span class="prelude-ty">Option</span><usize> { |
| <span class="kw">if </span>haystack.len() < <span class="number">64 </span>{ |
| rabinkarp::find(haystack, needle) |
| } <span class="kw">else </span>{ |
| Finder::new(needle).find(haystack) |
| } |
| } |
| |
| <span class="doccomment">/// Returns the index of the last occurrence of the given needle. |
| /// |
| /// Note that if you're are searching for the same needle in many different |
| /// small haystacks, it may be faster to initialize a [`FinderRev`] once, |
| /// and reuse it for each search. |
| /// |
| /// # Complexity |
| /// |
| /// This routine is guaranteed to have worst case linear time complexity |
| /// with respect to both the needle and the haystack. That is, this runs |
| /// in `O(needle.len() + haystack.len())` time. |
| /// |
| /// This routine is also guaranteed to have worst case constant space |
| /// complexity. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// use memchr::memmem; |
| /// |
| /// let haystack = b"foo bar baz"; |
| /// assert_eq!(Some(0), memmem::rfind(haystack, b"foo")); |
| /// assert_eq!(Some(4), memmem::rfind(haystack, b"bar")); |
| /// assert_eq!(Some(8), memmem::rfind(haystack, b"ba")); |
| /// assert_eq!(None, memmem::rfind(haystack, b"quux")); |
| /// ``` |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>rfind(haystack: <span class="kw-2">&</span>[u8], needle: <span class="kw-2">&</span>[u8]) -> <span class="prelude-ty">Option</span><usize> { |
| <span class="kw">if </span>haystack.len() < <span class="number">64 </span>{ |
| rabinkarp::rfind(haystack, needle) |
| } <span class="kw">else </span>{ |
| FinderRev::new(needle).rfind(haystack) |
| } |
| } |
| |
| <span class="doccomment">/// An iterator over non-overlapping substring matches. |
| /// |
| /// Matches are reported by the byte offset at which they begin. |
| /// |
| /// `'h` is the lifetime of the haystack while `'n` is the lifetime of the |
| /// needle. |
| </span><span class="attribute">#[derive(Debug)] |
| </span><span class="kw">pub struct </span>FindIter<<span class="lifetime">'h</span>, <span class="lifetime">'n</span>> { |
| haystack: <span class="kw-2">&</span><span class="lifetime">'h </span>[u8], |
| prestate: PrefilterState, |
| finder: Finder<<span class="lifetime">'n</span>>, |
| pos: usize, |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'h</span>, <span class="lifetime">'n</span>> FindIter<<span class="lifetime">'h</span>, <span class="lifetime">'n</span>> { |
| <span class="attribute">#[inline(always)] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>new( |
| haystack: <span class="kw-2">&</span><span class="lifetime">'h </span>[u8], |
| finder: Finder<<span class="lifetime">'n</span>>, |
| ) -> FindIter<<span class="lifetime">'h</span>, <span class="lifetime">'n</span>> { |
| <span class="kw">let </span>prestate = finder.searcher.prefilter_state(); |
| FindIter { haystack, prestate, finder, pos: <span class="number">0 </span>} |
| } |
| |
| <span class="doccomment">/// Convert this iterator into its owned variant, such that it no longer |
| /// borrows the finder and needle. |
| /// |
| /// If this is already an owned iterator, then this is a no-op. Otherwise, |
| /// this copies the needle. |
| /// |
| /// This is only available when the `std` feature is enabled. |
| </span><span class="attribute">#[cfg(feature = <span class="string">"std"</span>)] |
| #[inline] |
| </span><span class="kw">pub fn </span>into_owned(<span class="self">self</span>) -> FindIter<<span class="lifetime">'h</span>, <span class="lifetime">'static</span>> { |
| FindIter { |
| haystack: <span class="self">self</span>.haystack, |
| prestate: <span class="self">self</span>.prestate, |
| finder: <span class="self">self</span>.finder.into_owned(), |
| pos: <span class="self">self</span>.pos, |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'h</span>, <span class="lifetime">'n</span>> Iterator <span class="kw">for </span>FindIter<<span class="lifetime">'h</span>, <span class="lifetime">'n</span>> { |
| <span class="kw">type </span>Item = usize; |
| |
| <span class="kw">fn </span>next(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><usize> { |
| <span class="kw">if </span><span class="self">self</span>.pos > <span class="self">self</span>.haystack.len() { |
| <span class="kw">return </span><span class="prelude-val">None</span>; |
| } |
| <span class="kw">let </span>result = <span class="self">self |
| </span>.finder |
| .searcher |
| .find(<span class="kw-2">&mut </span><span class="self">self</span>.prestate, <span class="kw-2">&</span><span class="self">self</span>.haystack[<span class="self">self</span>.pos..]); |
| <span class="kw">match </span>result { |
| <span class="prelude-val">None </span>=> <span class="prelude-val">None</span>, |
| <span class="prelude-val">Some</span>(i) => { |
| <span class="kw">let </span>pos = <span class="self">self</span>.pos + i; |
| <span class="self">self</span>.pos = pos + core::cmp::max(<span class="number">1</span>, <span class="self">self</span>.finder.needle().len()); |
| <span class="prelude-val">Some</span>(pos) |
| } |
| } |
| } |
| } |
| |
| <span class="doccomment">/// An iterator over non-overlapping substring matches in reverse. |
| /// |
| /// Matches are reported by the byte offset at which they begin. |
| /// |
| /// `'h` is the lifetime of the haystack while `'n` is the lifetime of the |
| /// needle. |
| </span><span class="attribute">#[derive(Debug)] |
| </span><span class="kw">pub struct </span>FindRevIter<<span class="lifetime">'h</span>, <span class="lifetime">'n</span>> { |
| haystack: <span class="kw-2">&</span><span class="lifetime">'h </span>[u8], |
| finder: FinderRev<<span class="lifetime">'n</span>>, |
| <span class="doccomment">/// When searching with an empty needle, this gets set to `None` after |
| /// we've yielded the last element at `0`. |
| </span>pos: <span class="prelude-ty">Option</span><usize>, |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'h</span>, <span class="lifetime">'n</span>> FindRevIter<<span class="lifetime">'h</span>, <span class="lifetime">'n</span>> { |
| <span class="attribute">#[inline(always)] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>new( |
| haystack: <span class="kw-2">&</span><span class="lifetime">'h </span>[u8], |
| finder: FinderRev<<span class="lifetime">'n</span>>, |
| ) -> FindRevIter<<span class="lifetime">'h</span>, <span class="lifetime">'n</span>> { |
| <span class="kw">let </span>pos = <span class="prelude-val">Some</span>(haystack.len()); |
| FindRevIter { haystack, finder, pos } |
| } |
| |
| <span class="doccomment">/// Convert this iterator into its owned variant, such that it no longer |
| /// borrows the finder and needle. |
| /// |
| /// If this is already an owned iterator, then this is a no-op. Otherwise, |
| /// this copies the needle. |
| /// |
| /// This is only available when the `std` feature is enabled. |
| </span><span class="attribute">#[cfg(feature = <span class="string">"std"</span>)] |
| #[inline] |
| </span><span class="kw">pub fn </span>into_owned(<span class="self">self</span>) -> FindRevIter<<span class="lifetime">'h</span>, <span class="lifetime">'static</span>> { |
| FindRevIter { |
| haystack: <span class="self">self</span>.haystack, |
| finder: <span class="self">self</span>.finder.into_owned(), |
| pos: <span class="self">self</span>.pos, |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'h</span>, <span class="lifetime">'n</span>> Iterator <span class="kw">for </span>FindRevIter<<span class="lifetime">'h</span>, <span class="lifetime">'n</span>> { |
| <span class="kw">type </span>Item = usize; |
| |
| <span class="kw">fn </span>next(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><usize> { |
| <span class="kw">let </span>pos = <span class="kw">match </span><span class="self">self</span>.pos { |
| <span class="prelude-val">None </span>=> <span class="kw">return </span><span class="prelude-val">None</span>, |
| <span class="prelude-val">Some</span>(pos) => pos, |
| }; |
| <span class="kw">let </span>result = <span class="self">self</span>.finder.rfind(<span class="kw-2">&</span><span class="self">self</span>.haystack[..pos]); |
| <span class="kw">match </span>result { |
| <span class="prelude-val">None </span>=> <span class="prelude-val">None</span>, |
| <span class="prelude-val">Some</span>(i) => { |
| <span class="kw">if </span>pos == i { |
| <span class="self">self</span>.pos = pos.checked_sub(<span class="number">1</span>); |
| } <span class="kw">else </span>{ |
| <span class="self">self</span>.pos = <span class="prelude-val">Some</span>(i); |
| } |
| <span class="prelude-val">Some</span>(i) |
| } |
| } |
| } |
| } |
| |
| <span class="doccomment">/// A single substring searcher fixed to a particular needle. |
| /// |
| /// The purpose of this type is to permit callers to construct a substring |
| /// searcher that can be used to search haystacks without the overhead of |
| /// constructing the searcher in the first place. This is a somewhat niche |
| /// concern when it's necessary to re-use the same needle to search multiple |
| /// different haystacks with as little overhead as possible. In general, using |
| /// [`find`] is good enough, but `Finder` is useful when you can meaningfully |
| /// observe searcher construction time in a profile. |
| /// |
| /// When the `std` feature is enabled, then this type has an `into_owned` |
| /// version which permits building a `Finder` that is not connected to |
| /// the lifetime of its needle. |
| </span><span class="attribute">#[derive(Clone, Debug)] |
| </span><span class="kw">pub struct </span>Finder<<span class="lifetime">'n</span>> { |
| searcher: Searcher<<span class="lifetime">'n</span>>, |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'n</span>> Finder<<span class="lifetime">'n</span>> { |
| <span class="doccomment">/// Create a new finder for the given needle. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>new<B: <span class="question-mark">?</span>Sized + AsRef<[u8]>>(needle: <span class="kw-2">&</span><span class="lifetime">'n </span>B) -> Finder<<span class="lifetime">'n</span>> { |
| FinderBuilder::new().build_forward(needle) |
| } |
| |
| <span class="doccomment">/// Returns the index of the first occurrence of this needle in the given |
| /// haystack. |
| /// |
| /// # Complexity |
| /// |
| /// This routine is guaranteed to have worst case linear time complexity |
| /// with respect to both the needle and the haystack. That is, this runs |
| /// in `O(needle.len() + haystack.len())` time. |
| /// |
| /// This routine is also guaranteed to have worst case constant space |
| /// complexity. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// use memchr::memmem::Finder; |
| /// |
| /// let haystack = b"foo bar baz"; |
| /// assert_eq!(Some(0), Finder::new("foo").find(haystack)); |
| /// assert_eq!(Some(4), Finder::new("bar").find(haystack)); |
| /// assert_eq!(None, Finder::new("quux").find(haystack)); |
| /// ``` |
| </span><span class="kw">pub fn </span>find(<span class="kw-2">&</span><span class="self">self</span>, haystack: <span class="kw-2">&</span>[u8]) -> <span class="prelude-ty">Option</span><usize> { |
| <span class="self">self</span>.searcher.find(<span class="kw-2">&mut </span><span class="self">self</span>.searcher.prefilter_state(), haystack) |
| } |
| |
| <span class="doccomment">/// Returns an iterator over all occurrences of a substring in a haystack. |
| /// |
| /// # Complexity |
| /// |
| /// This routine is guaranteed to have worst case linear time complexity |
| /// with respect to both the needle and the haystack. That is, this runs |
| /// in `O(needle.len() + haystack.len())` time. |
| /// |
| /// This routine is also guaranteed to have worst case constant space |
| /// complexity. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// use memchr::memmem::Finder; |
| /// |
| /// let haystack = b"foo bar foo baz foo"; |
| /// let finder = Finder::new(b"foo"); |
| /// let mut it = finder.find_iter(haystack); |
| /// assert_eq!(Some(0), it.next()); |
| /// assert_eq!(Some(8), it.next()); |
| /// assert_eq!(Some(16), it.next()); |
| /// assert_eq!(None, it.next()); |
| /// ``` |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>find_iter<<span class="lifetime">'a</span>, <span class="lifetime">'h</span>>( |
| <span class="kw-2">&</span><span class="lifetime">'a </span><span class="self">self</span>, |
| haystack: <span class="kw-2">&</span><span class="lifetime">'h </span>[u8], |
| ) -> FindIter<<span class="lifetime">'h</span>, <span class="lifetime">'a</span>> { |
| FindIter::new(haystack, <span class="self">self</span>.as_ref()) |
| } |
| |
| <span class="doccomment">/// Convert this finder into its owned variant, such that it no longer |
| /// borrows the needle. |
| /// |
| /// If this is already an owned finder, then this is a no-op. Otherwise, |
| /// this copies the needle. |
| /// |
| /// This is only available when the `std` feature is enabled. |
| </span><span class="attribute">#[cfg(feature = <span class="string">"std"</span>)] |
| #[inline] |
| </span><span class="kw">pub fn </span>into_owned(<span class="self">self</span>) -> Finder<<span class="lifetime">'static</span>> { |
| Finder { searcher: <span class="self">self</span>.searcher.into_owned() } |
| } |
| |
| <span class="doccomment">/// Convert this finder into its borrowed variant. |
| /// |
| /// This is primarily useful if your finder is owned and you'd like to |
| /// store its borrowed variant in some intermediate data structure. |
| /// |
| /// Note that the lifetime parameter of the returned finder is tied to the |
| /// lifetime of `self`, and may be shorter than the `'n` lifetime of the |
| /// needle itself. Namely, a finder's needle can be either borrowed or |
| /// owned, so the lifetime of the needle returned must necessarily be the |
| /// shorter of the two. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>as_ref(<span class="kw-2">&</span><span class="self">self</span>) -> Finder<<span class="lifetime">'_</span>> { |
| Finder { searcher: <span class="self">self</span>.searcher.as_ref() } |
| } |
| |
| <span class="doccomment">/// Returns the needle that this finder searches for. |
| /// |
| /// Note that the lifetime of the needle returned is tied to the lifetime |
| /// of the finder, and may be shorter than the `'n` lifetime. Namely, a |
| /// finder's needle can be either borrowed or owned, so the lifetime of the |
| /// needle returned must necessarily be the shorter of the two. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>needle(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span>[u8] { |
| <span class="self">self</span>.searcher.needle() |
| } |
| } |
| |
| <span class="doccomment">/// A single substring reverse searcher fixed to a particular needle. |
| /// |
| /// The purpose of this type is to permit callers to construct a substring |
| /// searcher that can be used to search haystacks without the overhead of |
| /// constructing the searcher in the first place. This is a somewhat niche |
| /// concern when it's necessary to re-use the same needle to search multiple |
| /// different haystacks with as little overhead as possible. In general, |
| /// using [`rfind`] is good enough, but `FinderRev` is useful when you can |
| /// meaningfully observe searcher construction time in a profile. |
| /// |
| /// When the `std` feature is enabled, then this type has an `into_owned` |
| /// version which permits building a `FinderRev` that is not connected to |
| /// the lifetime of its needle. |
| </span><span class="attribute">#[derive(Clone, Debug)] |
| </span><span class="kw">pub struct </span>FinderRev<<span class="lifetime">'n</span>> { |
| searcher: SearcherRev<<span class="lifetime">'n</span>>, |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'n</span>> FinderRev<<span class="lifetime">'n</span>> { |
| <span class="doccomment">/// Create a new reverse finder for the given needle. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>new<B: <span class="question-mark">?</span>Sized + AsRef<[u8]>>(needle: <span class="kw-2">&</span><span class="lifetime">'n </span>B) -> FinderRev<<span class="lifetime">'n</span>> { |
| FinderBuilder::new().build_reverse(needle) |
| } |
| |
| <span class="doccomment">/// Returns the index of the last occurrence of this needle in the given |
| /// haystack. |
| /// |
| /// The haystack may be any type that can be cheaply converted into a |
| /// `&[u8]`. This includes, but is not limited to, `&str` and `&[u8]`. |
| /// |
| /// # Complexity |
| /// |
| /// This routine is guaranteed to have worst case linear time complexity |
| /// with respect to both the needle and the haystack. That is, this runs |
| /// in `O(needle.len() + haystack.len())` time. |
| /// |
| /// This routine is also guaranteed to have worst case constant space |
| /// complexity. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// use memchr::memmem::FinderRev; |
| /// |
| /// let haystack = b"foo bar baz"; |
| /// assert_eq!(Some(0), FinderRev::new("foo").rfind(haystack)); |
| /// assert_eq!(Some(4), FinderRev::new("bar").rfind(haystack)); |
| /// assert_eq!(None, FinderRev::new("quux").rfind(haystack)); |
| /// ``` |
| </span><span class="kw">pub fn </span>rfind<B: AsRef<[u8]>>(<span class="kw-2">&</span><span class="self">self</span>, haystack: B) -> <span class="prelude-ty">Option</span><usize> { |
| <span class="self">self</span>.searcher.rfind(haystack.as_ref()) |
| } |
| |
| <span class="doccomment">/// Returns a reverse iterator over all occurrences of a substring in a |
| /// haystack. |
| /// |
| /// # Complexity |
| /// |
| /// This routine is guaranteed to have worst case linear time complexity |
| /// with respect to both the needle and the haystack. That is, this runs |
| /// in `O(needle.len() + haystack.len())` time. |
| /// |
| /// This routine is also guaranteed to have worst case constant space |
| /// complexity. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// use memchr::memmem::FinderRev; |
| /// |
| /// let haystack = b"foo bar foo baz foo"; |
| /// let finder = FinderRev::new(b"foo"); |
| /// let mut it = finder.rfind_iter(haystack); |
| /// assert_eq!(Some(16), it.next()); |
| /// assert_eq!(Some(8), it.next()); |
| /// assert_eq!(Some(0), it.next()); |
| /// assert_eq!(None, it.next()); |
| /// ``` |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>rfind_iter<<span class="lifetime">'a</span>, <span class="lifetime">'h</span>>( |
| <span class="kw-2">&</span><span class="lifetime">'a </span><span class="self">self</span>, |
| haystack: <span class="kw-2">&</span><span class="lifetime">'h </span>[u8], |
| ) -> FindRevIter<<span class="lifetime">'h</span>, <span class="lifetime">'a</span>> { |
| FindRevIter::new(haystack, <span class="self">self</span>.as_ref()) |
| } |
| |
| <span class="doccomment">/// Convert this finder into its owned variant, such that it no longer |
| /// borrows the needle. |
| /// |
| /// If this is already an owned finder, then this is a no-op. Otherwise, |
| /// this copies the needle. |
| /// |
| /// This is only available when the `std` feature is enabled. |
| </span><span class="attribute">#[cfg(feature = <span class="string">"std"</span>)] |
| #[inline] |
| </span><span class="kw">pub fn </span>into_owned(<span class="self">self</span>) -> FinderRev<<span class="lifetime">'static</span>> { |
| FinderRev { searcher: <span class="self">self</span>.searcher.into_owned() } |
| } |
| |
| <span class="doccomment">/// Convert this finder into its borrowed variant. |
| /// |
| /// This is primarily useful if your finder is owned and you'd like to |
| /// store its borrowed variant in some intermediate data structure. |
| /// |
| /// Note that the lifetime parameter of the returned finder is tied to the |
| /// lifetime of `self`, and may be shorter than the `'n` lifetime of the |
| /// needle itself. Namely, a finder's needle can be either borrowed or |
| /// owned, so the lifetime of the needle returned must necessarily be the |
| /// shorter of the two. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>as_ref(<span class="kw-2">&</span><span class="self">self</span>) -> FinderRev<<span class="lifetime">'_</span>> { |
| FinderRev { searcher: <span class="self">self</span>.searcher.as_ref() } |
| } |
| |
| <span class="doccomment">/// Returns the needle that this finder searches for. |
| /// |
| /// Note that the lifetime of the needle returned is tied to the lifetime |
| /// of the finder, and may be shorter than the `'n` lifetime. Namely, a |
| /// finder's needle can be either borrowed or owned, so the lifetime of the |
| /// needle returned must necessarily be the shorter of the two. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>needle(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span>[u8] { |
| <span class="self">self</span>.searcher.needle() |
| } |
| } |
| |
| <span class="doccomment">/// A builder for constructing non-default forward or reverse memmem finders. |
| /// |
| /// A builder is primarily useful for configuring a substring searcher. |
| /// Currently, the only configuration exposed is the ability to disable |
| /// heuristic prefilters used to speed up certain searches. |
| </span><span class="attribute">#[derive(Clone, Debug, Default)] |
| </span><span class="kw">pub struct </span>FinderBuilder { |
| config: SearcherConfig, |
| } |
| |
| <span class="kw">impl </span>FinderBuilder { |
| <span class="doccomment">/// Create a new finder builder with default settings. |
| </span><span class="kw">pub fn </span>new() -> FinderBuilder { |
| FinderBuilder::default() |
| } |
| |
| <span class="doccomment">/// Build a forward finder using the given needle from the current |
| /// settings. |
| </span><span class="kw">pub fn </span>build_forward<<span class="lifetime">'n</span>, B: <span class="question-mark">?</span>Sized + AsRef<[u8]>>( |
| <span class="kw-2">&</span><span class="self">self</span>, |
| needle: <span class="kw-2">&</span><span class="lifetime">'n </span>B, |
| ) -> Finder<<span class="lifetime">'n</span>> { |
| Finder { searcher: Searcher::new(<span class="self">self</span>.config, needle.as_ref()) } |
| } |
| |
| <span class="doccomment">/// Build a reverse finder using the given needle from the current |
| /// settings. |
| </span><span class="kw">pub fn </span>build_reverse<<span class="lifetime">'n</span>, B: <span class="question-mark">?</span>Sized + AsRef<[u8]>>( |
| <span class="kw-2">&</span><span class="self">self</span>, |
| needle: <span class="kw-2">&</span><span class="lifetime">'n </span>B, |
| ) -> FinderRev<<span class="lifetime">'n</span>> { |
| FinderRev { searcher: SearcherRev::new(needle.as_ref()) } |
| } |
| |
| <span class="doccomment">/// Configure the prefilter setting for the finder. |
| /// |
| /// See the documentation for [`Prefilter`] for more discussion on why |
| /// you might want to configure this. |
| </span><span class="kw">pub fn </span>prefilter(<span class="kw-2">&mut </span><span class="self">self</span>, prefilter: Prefilter) -> <span class="kw-2">&mut </span>FinderBuilder { |
| <span class="self">self</span>.config.prefilter = prefilter; |
| <span class="self">self |
| </span>} |
| } |
| |
| <span class="doccomment">/// The internal implementation of a forward substring searcher. |
| /// |
| /// The reality is that this is a "meta" searcher. Namely, depending on a |
| /// variety of parameters (CPU support, target, needle size, haystack size and |
| /// even dynamic properties such as prefilter effectiveness), the actual |
| /// algorithm employed to do substring search may change. |
| </span><span class="attribute">#[derive(Clone, Debug)] |
| </span><span class="kw">struct </span>Searcher<<span class="lifetime">'n</span>> { |
| <span class="doccomment">/// The actual needle we're searching for. |
| /// |
| /// A CowBytes is like a Cow<[u8]>, except in no_std environments, it is |
| /// specialized to a single variant (the borrowed form). |
| </span>needle: CowBytes<<span class="lifetime">'n</span>>, |
| <span class="doccomment">/// A collection of facts computed on the needle that are useful for more |
| /// than one substring search algorithm. |
| </span>ninfo: NeedleInfo, |
| <span class="doccomment">/// A prefilter function, if it was deemed appropriate. |
| /// |
| /// Some substring search implementations (like Two-Way) benefit greatly |
| /// if we can quickly find candidate starting positions for a match. |
| </span>prefn: <span class="prelude-ty">Option</span><PrefilterFn>, |
| <span class="doccomment">/// The actual substring implementation in use. |
| </span>kind: SearcherKind, |
| } |
| |
| <span class="doccomment">/// A collection of facts computed about a search needle. |
| /// |
| /// We group these things together because it's useful to be able to hand them |
| /// to prefilters or substring algorithms that want them. |
| </span><span class="attribute">#[derive(Clone, Copy, Debug)] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">struct </span>NeedleInfo { |
| <span class="doccomment">/// The offsets of "rare" bytes detected in the needle. |
| /// |
| /// This is meant to be a heuristic in order to maximize the effectiveness |
| /// of vectorized code. Namely, vectorized code tends to focus on only |
| /// one or two bytes. If we pick bytes from the needle that occur |
| /// infrequently, then more time will be spent in the vectorized code and |
| /// will likely make the overall search (much) faster. |
| /// |
| /// Of course, this is only a heuristic based on a background frequency |
| /// distribution of bytes. But it tends to work very well in practice. |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) rarebytes: RareNeedleBytes, |
| <span class="doccomment">/// A Rabin-Karp hash of the needle. |
| /// |
| /// This is store here instead of in a more specific Rabin-Karp search |
| /// since Rabin-Karp may be used even if another SearchKind corresponds |
| /// to some other search implementation. e.g., If measurements suggest RK |
| /// is faster in some cases or if a search implementation can't handle |
| /// particularly small haystack. (Moreover, we cannot use RK *generally*, |
| /// since its worst case time is multiplicative. Instead, we only use it |
| /// some small haystacks, where "small" is a constant.) |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) nhash: NeedleHash, |
| } |
| |
| <span class="doccomment">/// Configuration for substring search. |
| </span><span class="attribute">#[derive(Clone, Copy, Debug, Default)] |
| </span><span class="kw">struct </span>SearcherConfig { |
| <span class="doccomment">/// This permits changing the behavior of the prefilter, since it can have |
| /// a variable impact on performance. |
| </span>prefilter: Prefilter, |
| } |
| |
| <span class="attribute">#[derive(Clone, Debug)] |
| </span><span class="kw">enum </span>SearcherKind { |
| <span class="doccomment">/// A special case for empty needles. An empty needle always matches, even |
| /// in an empty haystack. |
| </span>Empty, |
| <span class="doccomment">/// This is used whenever the needle is a single byte. In this case, we |
| /// always use memchr. |
| </span>OneByte(u8), |
| <span class="doccomment">/// Two-Way is the generic work horse and is what provides our additive |
| /// linear time guarantee. In general, it's used when the needle is bigger |
| /// than 8 bytes or so. |
| </span>TwoWay(twoway::Forward), |
| <span class="attribute">#[cfg(all(not(miri), target_arch = <span class="string">"x86_64"</span>, memchr_runtime_simd))] |
| </span>GenericSIMD128(x86::sse::Forward), |
| <span class="attribute">#[cfg(memchr_runtime_wasm128)] |
| </span>GenericSIMD128(wasm::Forward), |
| <span class="attribute">#[cfg(all(not(miri), target_arch = <span class="string">"x86_64"</span>, memchr_runtime_simd))] |
| </span>GenericSIMD256(x86::avx::Forward), |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'n</span>> Searcher<<span class="lifetime">'n</span>> { |
| <span class="kw">fn </span>new(config: SearcherConfig, needle: <span class="kw-2">&</span><span class="lifetime">'n </span>[u8]) -> Searcher<<span class="lifetime">'n</span>> { |
| <span class="kw">use </span><span class="self">self</span>::SearcherKind::<span class="kw-2">*</span>; |
| |
| <span class="kw">let </span>ninfo = NeedleInfo::new(needle); |
| <span class="kw">let </span>mk = |kind: SearcherKind| { |
| <span class="kw">let </span>prefn = prefilter::forward( |
| <span class="kw-2">&</span>config.prefilter, |
| <span class="kw-2">&</span>ninfo.rarebytes, |
| needle, |
| ); |
| Searcher { needle: CowBytes::new(needle), ninfo, prefn, kind } |
| }; |
| <span class="kw">if </span>needle.len() == <span class="number">0 </span>{ |
| <span class="kw">return </span>mk(Empty); |
| } |
| <span class="kw">if </span>needle.len() == <span class="number">1 </span>{ |
| <span class="kw">return </span>mk(OneByte(needle[<span class="number">0</span>])); |
| } |
| <span class="attribute">#[cfg(all(not(miri), target_arch = <span class="string">"x86_64"</span>, memchr_runtime_simd))] |
| </span>{ |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(fwd) = x86::avx::Forward::new(<span class="kw-2">&</span>ninfo, needle) { |
| <span class="kw">return </span>mk(GenericSIMD256(fwd)); |
| } <span class="kw">else if let </span><span class="prelude-val">Some</span>(fwd) = x86::sse::Forward::new(<span class="kw-2">&</span>ninfo, needle) { |
| <span class="kw">return </span>mk(GenericSIMD128(fwd)); |
| } |
| } |
| <span class="attribute">#[cfg(all(target_arch = <span class="string">"wasm32"</span>, memchr_runtime_simd))] |
| </span>{ |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(fwd) = wasm::Forward::new(<span class="kw-2">&</span>ninfo, needle) { |
| <span class="kw">return </span>mk(GenericSIMD128(fwd)); |
| } |
| } |
| |
| mk(TwoWay(twoway::Forward::new(needle))) |
| } |
| |
| <span class="doccomment">/// Return a fresh prefilter state that can be used with this searcher. |
| /// A prefilter state is used to track the effectiveness of a searcher's |
| /// prefilter for speeding up searches. Therefore, the prefilter state |
| /// should generally be reused on subsequent searches (such as in an |
| /// iterator). For searches on a different haystack, then a new prefilter |
| /// state should be used. |
| /// |
| /// This always initializes a valid (but possibly inert) prefilter state |
| /// even if this searcher does not have a prefilter enabled. |
| </span><span class="kw">fn </span>prefilter_state(<span class="kw-2">&</span><span class="self">self</span>) -> PrefilterState { |
| <span class="kw">if </span><span class="self">self</span>.prefn.is_none() { |
| PrefilterState::inert() |
| } <span class="kw">else </span>{ |
| PrefilterState::new() |
| } |
| } |
| |
| <span class="kw">fn </span>needle(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span>[u8] { |
| <span class="self">self</span>.needle.as_slice() |
| } |
| |
| <span class="kw">fn </span>as_ref(<span class="kw-2">&</span><span class="self">self</span>) -> Searcher<<span class="lifetime">'_</span>> { |
| <span class="kw">use </span><span class="self">self</span>::SearcherKind::<span class="kw-2">*</span>; |
| |
| <span class="kw">let </span>kind = <span class="kw">match </span><span class="self">self</span>.kind { |
| Empty => Empty, |
| OneByte(b) => OneByte(b), |
| TwoWay(tw) => TwoWay(tw), |
| <span class="attribute">#[cfg(all(not(miri), memchr_runtime_simd))] |
| </span>GenericSIMD128(gs) => GenericSIMD128(gs), |
| <span class="attribute">#[cfg(all( |
| not(miri), |
| target_arch = <span class="string">"x86_64"</span>, |
| memchr_runtime_simd |
| ))] |
| </span>GenericSIMD256(gs) => GenericSIMD256(gs), |
| }; |
| Searcher { |
| needle: CowBytes::new(<span class="self">self</span>.needle()), |
| ninfo: <span class="self">self</span>.ninfo, |
| prefn: <span class="self">self</span>.prefn, |
| kind, |
| } |
| } |
| |
| <span class="attribute">#[cfg(feature = <span class="string">"std"</span>)] |
| </span><span class="kw">fn </span>into_owned(<span class="self">self</span>) -> Searcher<<span class="lifetime">'static</span>> { |
| <span class="kw">use </span><span class="self">self</span>::SearcherKind::<span class="kw-2">*</span>; |
| |
| <span class="kw">let </span>kind = <span class="kw">match </span><span class="self">self</span>.kind { |
| Empty => Empty, |
| OneByte(b) => OneByte(b), |
| TwoWay(tw) => TwoWay(tw), |
| <span class="attribute">#[cfg(all(not(miri), memchr_runtime_simd))] |
| </span>GenericSIMD128(gs) => GenericSIMD128(gs), |
| <span class="attribute">#[cfg(all( |
| not(miri), |
| target_arch = <span class="string">"x86_64"</span>, |
| memchr_runtime_simd |
| ))] |
| </span>GenericSIMD256(gs) => GenericSIMD256(gs), |
| }; |
| Searcher { |
| needle: <span class="self">self</span>.needle.into_owned(), |
| ninfo: <span class="self">self</span>.ninfo, |
| prefn: <span class="self">self</span>.prefn, |
| kind, |
| } |
| } |
| |
| <span class="doccomment">/// Implements forward substring search by selecting the implementation |
| /// chosen at construction and executing it on the given haystack with the |
| /// prefilter's current state of effectiveness. |
| </span><span class="attribute">#[inline(always)] |
| </span><span class="kw">fn </span>find( |
| <span class="kw-2">&</span><span class="self">self</span>, |
| state: <span class="kw-2">&mut </span>PrefilterState, |
| haystack: <span class="kw-2">&</span>[u8], |
| ) -> <span class="prelude-ty">Option</span><usize> { |
| <span class="kw">use </span><span class="self">self</span>::SearcherKind::<span class="kw-2">*</span>; |
| |
| <span class="kw">let </span>needle = <span class="self">self</span>.needle(); |
| <span class="kw">if </span>haystack.len() < needle.len() { |
| <span class="kw">return </span><span class="prelude-val">None</span>; |
| } |
| <span class="kw">match </span><span class="self">self</span>.kind { |
| Empty => <span class="prelude-val">Some</span>(<span class="number">0</span>), |
| OneByte(b) => <span class="kw">crate</span>::memchr(b, haystack), |
| TwoWay(<span class="kw-2">ref </span>tw) => { |
| <span class="comment">// For very short haystacks (e.g., where the prefilter probably |
| // can't run), it's faster to just run RK. |
| </span><span class="kw">if </span>rabinkarp::is_fast(haystack, needle) { |
| rabinkarp::find_with(<span class="kw-2">&</span><span class="self">self</span>.ninfo.nhash, haystack, needle) |
| } <span class="kw">else </span>{ |
| <span class="self">self</span>.find_tw(tw, state, haystack, needle) |
| } |
| } |
| <span class="attribute">#[cfg(all(not(miri), memchr_runtime_simd))] |
| </span>GenericSIMD128(<span class="kw-2">ref </span>gs) => { |
| <span class="comment">// The SIMD matcher can't handle particularly short haystacks, |
| // so we fall back to RK in these cases. |
| </span><span class="kw">if </span>haystack.len() < gs.min_haystack_len() { |
| rabinkarp::find_with(<span class="kw-2">&</span><span class="self">self</span>.ninfo.nhash, haystack, needle) |
| } <span class="kw">else </span>{ |
| gs.find(haystack, needle) |
| } |
| } |
| <span class="attribute">#[cfg(all( |
| not(miri), |
| target_arch = <span class="string">"x86_64"</span>, |
| memchr_runtime_simd |
| ))] |
| </span>GenericSIMD256(<span class="kw-2">ref </span>gs) => { |
| <span class="comment">// The SIMD matcher can't handle particularly short haystacks, |
| // so we fall back to RK in these cases. |
| </span><span class="kw">if </span>haystack.len() < gs.min_haystack_len() { |
| rabinkarp::find_with(<span class="kw-2">&</span><span class="self">self</span>.ninfo.nhash, haystack, needle) |
| } <span class="kw">else </span>{ |
| gs.find(haystack, needle) |
| } |
| } |
| } |
| } |
| |
| <span class="doccomment">/// Calls Two-Way on the given haystack/needle. |
| /// |
| /// This is marked as unlineable since it seems to have a better overall |
| /// effect on benchmarks. However, this is one of those cases where |
| /// inlining it results an improvement in other benchmarks too, so I |
| /// suspect we just don't have enough data yet to make the right call here. |
| /// |
| /// I suspect the main problem is that this function contains two different |
| /// inlined copies of Two-Way: one with and one without prefilters enabled. |
| </span><span class="attribute">#[inline(never)] |
| </span><span class="kw">fn </span>find_tw( |
| <span class="kw-2">&</span><span class="self">self</span>, |
| tw: <span class="kw-2">&</span>twoway::Forward, |
| state: <span class="kw-2">&mut </span>PrefilterState, |
| haystack: <span class="kw-2">&</span>[u8], |
| needle: <span class="kw-2">&</span>[u8], |
| ) -> <span class="prelude-ty">Option</span><usize> { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(prefn) = <span class="self">self</span>.prefn { |
| <span class="comment">// We used to look at the length of a haystack here. That is, if |
| // it was too small, then don't bother with the prefilter. But two |
| // things changed: the prefilter falls back to memchr for small |
| // haystacks, and, above, Rabin-Karp is employed for tiny haystacks |
| // anyway. |
| </span><span class="kw">if </span>state.is_effective() { |
| <span class="kw">let </span><span class="kw-2">mut </span>pre = Pre { state, prefn, ninfo: <span class="kw-2">&</span><span class="self">self</span>.ninfo }; |
| <span class="kw">return </span>tw.find(<span class="prelude-val">Some</span>(<span class="kw-2">&mut </span>pre), haystack, needle); |
| } |
| } |
| tw.find(<span class="prelude-val">None</span>, haystack, needle) |
| } |
| } |
| |
| <span class="kw">impl </span>NeedleInfo { |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>new(needle: <span class="kw-2">&</span>[u8]) -> NeedleInfo { |
| NeedleInfo { |
| rarebytes: RareNeedleBytes::forward(needle), |
| nhash: NeedleHash::forward(needle), |
| } |
| } |
| } |
| |
| <span class="doccomment">/// The internal implementation of a reverse substring searcher. |
| /// |
| /// See the forward searcher docs for more details. Currently, the reverse |
| /// searcher is considerably simpler since it lacks prefilter support. This |
| /// was done because it adds a lot of code, and more surface area to test. And |
| /// in particular, it's not clear whether a prefilter on reverse searching is |
| /// worth it. (If you have a compelling use case, please file an issue!) |
| </span><span class="attribute">#[derive(Clone, Debug)] |
| </span><span class="kw">struct </span>SearcherRev<<span class="lifetime">'n</span>> { |
| <span class="doccomment">/// The actual needle we're searching for. |
| </span>needle: CowBytes<<span class="lifetime">'n</span>>, |
| <span class="doccomment">/// A Rabin-Karp hash of the needle. |
| </span>nhash: NeedleHash, |
| <span class="doccomment">/// The actual substring implementation in use. |
| </span>kind: SearcherRevKind, |
| } |
| |
| <span class="attribute">#[derive(Clone, Debug)] |
| </span><span class="kw">enum </span>SearcherRevKind { |
| <span class="doccomment">/// A special case for empty needles. An empty needle always matches, even |
| /// in an empty haystack. |
| </span>Empty, |
| <span class="doccomment">/// This is used whenever the needle is a single byte. In this case, we |
| /// always use memchr. |
| </span>OneByte(u8), |
| <span class="doccomment">/// Two-Way is the generic work horse and is what provides our additive |
| /// linear time guarantee. In general, it's used when the needle is bigger |
| /// than 8 bytes or so. |
| </span>TwoWay(twoway::Reverse), |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'n</span>> SearcherRev<<span class="lifetime">'n</span>> { |
| <span class="kw">fn </span>new(needle: <span class="kw-2">&</span><span class="lifetime">'n </span>[u8]) -> SearcherRev<<span class="lifetime">'n</span>> { |
| <span class="kw">use </span><span class="self">self</span>::SearcherRevKind::<span class="kw-2">*</span>; |
| |
| <span class="kw">let </span>kind = <span class="kw">if </span>needle.len() == <span class="number">0 </span>{ |
| Empty |
| } <span class="kw">else if </span>needle.len() == <span class="number">1 </span>{ |
| OneByte(needle[<span class="number">0</span>]) |
| } <span class="kw">else </span>{ |
| TwoWay(twoway::Reverse::new(needle)) |
| }; |
| SearcherRev { |
| needle: CowBytes::new(needle), |
| nhash: NeedleHash::reverse(needle), |
| kind, |
| } |
| } |
| |
| <span class="kw">fn </span>needle(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span>[u8] { |
| <span class="self">self</span>.needle.as_slice() |
| } |
| |
| <span class="kw">fn </span>as_ref(<span class="kw-2">&</span><span class="self">self</span>) -> SearcherRev<<span class="lifetime">'_</span>> { |
| <span class="kw">use </span><span class="self">self</span>::SearcherRevKind::<span class="kw-2">*</span>; |
| |
| <span class="kw">let </span>kind = <span class="kw">match </span><span class="self">self</span>.kind { |
| Empty => Empty, |
| OneByte(b) => OneByte(b), |
| TwoWay(tw) => TwoWay(tw), |
| }; |
| SearcherRev { |
| needle: CowBytes::new(<span class="self">self</span>.needle()), |
| nhash: <span class="self">self</span>.nhash, |
| kind, |
| } |
| } |
| |
| <span class="attribute">#[cfg(feature = <span class="string">"std"</span>)] |
| </span><span class="kw">fn </span>into_owned(<span class="self">self</span>) -> SearcherRev<<span class="lifetime">'static</span>> { |
| <span class="kw">use </span><span class="self">self</span>::SearcherRevKind::<span class="kw-2">*</span>; |
| |
| <span class="kw">let </span>kind = <span class="kw">match </span><span class="self">self</span>.kind { |
| Empty => Empty, |
| OneByte(b) => OneByte(b), |
| TwoWay(tw) => TwoWay(tw), |
| }; |
| SearcherRev { |
| needle: <span class="self">self</span>.needle.into_owned(), |
| nhash: <span class="self">self</span>.nhash, |
| kind, |
| } |
| } |
| |
| <span class="doccomment">/// Implements reverse substring search by selecting the implementation |
| /// chosen at construction and executing it on the given haystack with the |
| /// prefilter's current state of effectiveness. |
| </span><span class="attribute">#[inline(always)] |
| </span><span class="kw">fn </span>rfind(<span class="kw-2">&</span><span class="self">self</span>, haystack: <span class="kw-2">&</span>[u8]) -> <span class="prelude-ty">Option</span><usize> { |
| <span class="kw">use </span><span class="self">self</span>::SearcherRevKind::<span class="kw-2">*</span>; |
| |
| <span class="kw">let </span>needle = <span class="self">self</span>.needle(); |
| <span class="kw">if </span>haystack.len() < needle.len() { |
| <span class="kw">return </span><span class="prelude-val">None</span>; |
| } |
| <span class="kw">match </span><span class="self">self</span>.kind { |
| Empty => <span class="prelude-val">Some</span>(haystack.len()), |
| OneByte(b) => <span class="kw">crate</span>::memrchr(b, haystack), |
| TwoWay(<span class="kw-2">ref </span>tw) => { |
| <span class="comment">// For very short haystacks (e.g., where the prefilter probably |
| // can't run), it's faster to just run RK. |
| </span><span class="kw">if </span>rabinkarp::is_fast(haystack, needle) { |
| rabinkarp::rfind_with(<span class="kw-2">&</span><span class="self">self</span>.nhash, haystack, needle) |
| } <span class="kw">else </span>{ |
| tw.rfind(haystack, needle) |
| } |
| } |
| } |
| } |
| } |
| |
| <span class="doccomment">/// This module defines some generic quickcheck properties useful for testing |
| /// any substring search algorithm. It also runs those properties for the |
| /// top-level public API memmem routines. (The properties are also used to |
| /// test various substring search implementations more granularly elsewhere as |
| /// well.) |
| </span><span class="attribute">#[cfg(all(test, feature = <span class="string">"std"</span>, not(miri)))] |
| </span><span class="kw">mod </span>proptests { |
| <span class="comment">// N.B. This defines the quickcheck tests using the properties defined |
| // below. Because of macro-visibility weirdness, the actual macro is |
| // defined at the top of this file. |
| </span><span class="macro">define_memmem_quickcheck_tests!</span>(<span class="kw">super</span>::find, <span class="kw">super</span>::rfind); |
| |
| <span class="doccomment">/// Check that every prefix of the given byte string is a substring. |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>prefix_is_substring( |
| reverse: bool, |
| bs: <span class="kw-2">&</span>[u8], |
| <span class="kw-2">mut </span>search: <span class="kw">impl </span>FnMut(<span class="kw-2">&</span>[u8], <span class="kw-2">&</span>[u8]) -> <span class="prelude-ty">Option</span><usize>, |
| ) -> bool { |
| <span class="kw">if </span>bs.is_empty() { |
| <span class="kw">return </span><span class="bool-val">true</span>; |
| } |
| <span class="kw">for </span>i <span class="kw">in </span><span class="number">0</span>..(bs.len() - <span class="number">1</span>) { |
| <span class="kw">let </span>prefix = <span class="kw-2">&</span>bs[..i]; |
| <span class="kw">if </span>reverse { |
| <span class="macro">assert_eq!</span>(naive_rfind(bs, prefix), search(bs, prefix)); |
| } <span class="kw">else </span>{ |
| <span class="macro">assert_eq!</span>(naive_find(bs, prefix), search(bs, prefix)); |
| } |
| } |
| <span class="bool-val">true |
| </span>} |
| |
| <span class="doccomment">/// Check that every suffix of the given byte string is a substring. |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>suffix_is_substring( |
| reverse: bool, |
| bs: <span class="kw-2">&</span>[u8], |
| <span class="kw-2">mut </span>search: <span class="kw">impl </span>FnMut(<span class="kw-2">&</span>[u8], <span class="kw-2">&</span>[u8]) -> <span class="prelude-ty">Option</span><usize>, |
| ) -> bool { |
| <span class="kw">if </span>bs.is_empty() { |
| <span class="kw">return </span><span class="bool-val">true</span>; |
| } |
| <span class="kw">for </span>i <span class="kw">in </span><span class="number">0</span>..(bs.len() - <span class="number">1</span>) { |
| <span class="kw">let </span>suffix = <span class="kw-2">&</span>bs[i..]; |
| <span class="kw">if </span>reverse { |
| <span class="macro">assert_eq!</span>(naive_rfind(bs, suffix), search(bs, suffix)); |
| } <span class="kw">else </span>{ |
| <span class="macro">assert_eq!</span>(naive_find(bs, suffix), search(bs, suffix)); |
| } |
| } |
| <span class="bool-val">true |
| </span>} |
| |
| <span class="doccomment">/// Check that naive substring search matches the result of the given search |
| /// algorithm. |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>matches_naive( |
| reverse: bool, |
| haystack: <span class="kw-2">&</span>[u8], |
| needle: <span class="kw-2">&</span>[u8], |
| <span class="kw-2">mut </span>search: <span class="kw">impl </span>FnMut(<span class="kw-2">&</span>[u8], <span class="kw-2">&</span>[u8]) -> <span class="prelude-ty">Option</span><usize>, |
| ) -> bool { |
| <span class="kw">if </span>reverse { |
| naive_rfind(haystack, needle) == search(haystack, needle) |
| } <span class="kw">else </span>{ |
| naive_find(haystack, needle) == search(haystack, needle) |
| } |
| } |
| |
| <span class="doccomment">/// Naively search forwards for the given needle in the given haystack. |
| </span><span class="kw">fn </span>naive_find(haystack: <span class="kw-2">&</span>[u8], needle: <span class="kw-2">&</span>[u8]) -> <span class="prelude-ty">Option</span><usize> { |
| <span class="kw">if </span>needle.is_empty() { |
| <span class="kw">return </span><span class="prelude-val">Some</span>(<span class="number">0</span>); |
| } <span class="kw">else if </span>haystack.len() < needle.len() { |
| <span class="kw">return </span><span class="prelude-val">None</span>; |
| } |
| <span class="kw">for </span>i <span class="kw">in </span><span class="number">0</span>..(haystack.len() - needle.len() + <span class="number">1</span>) { |
| <span class="kw">if </span>needle == <span class="kw-2">&</span>haystack[i..i + needle.len()] { |
| <span class="kw">return </span><span class="prelude-val">Some</span>(i); |
| } |
| } |
| <span class="prelude-val">None |
| </span>} |
| |
| <span class="doccomment">/// Naively search in reverse for the given needle in the given haystack. |
| </span><span class="kw">fn </span>naive_rfind(haystack: <span class="kw-2">&</span>[u8], needle: <span class="kw-2">&</span>[u8]) -> <span class="prelude-ty">Option</span><usize> { |
| <span class="kw">if </span>needle.is_empty() { |
| <span class="kw">return </span><span class="prelude-val">Some</span>(haystack.len()); |
| } <span class="kw">else if </span>haystack.len() < needle.len() { |
| <span class="kw">return </span><span class="prelude-val">None</span>; |
| } |
| <span class="kw">for </span>i <span class="kw">in </span>(<span class="number">0</span>..(haystack.len() - needle.len() + <span class="number">1</span>)).rev() { |
| <span class="kw">if </span>needle == <span class="kw-2">&</span>haystack[i..i + needle.len()] { |
| <span class="kw">return </span><span class="prelude-val">Some</span>(i); |
| } |
| } |
| <span class="prelude-val">None |
| </span>} |
| } |
| |
| <span class="doccomment">/// This module defines some hand-written "simple" substring tests. It |
| /// also provides routines for easily running them on any substring search |
| /// implementation. |
| </span><span class="attribute">#[cfg(test)] |
| </span><span class="kw">mod </span>testsimples { |
| <span class="macro">define_memmem_simple_tests!</span>(<span class="kw">super</span>::find, <span class="kw">super</span>::rfind); |
| |
| <span class="doccomment">/// Each test is a (needle, haystack, expected_fwd, expected_rev) tuple. |
| </span><span class="kw">type </span>SearchTest = |
| (<span class="kw-2">&</span><span class="lifetime">'static </span>str, <span class="kw-2">&</span><span class="lifetime">'static </span>str, <span class="prelude-ty">Option</span><usize>, <span class="prelude-ty">Option</span><usize>); |
| |
| <span class="kw">const </span>SEARCH_TESTS: <span class="kw-2">&</span><span class="lifetime">'static </span>[SearchTest] = <span class="kw-2">&</span>[ |
| (<span class="string">""</span>, <span class="string">""</span>, <span class="prelude-val">Some</span>(<span class="number">0</span>), <span class="prelude-val">Some</span>(<span class="number">0</span>)), |
| (<span class="string">""</span>, <span class="string">"a"</span>, <span class="prelude-val">Some</span>(<span class="number">0</span>), <span class="prelude-val">Some</span>(<span class="number">1</span>)), |
| (<span class="string">""</span>, <span class="string">"ab"</span>, <span class="prelude-val">Some</span>(<span class="number">0</span>), <span class="prelude-val">Some</span>(<span class="number">2</span>)), |
| (<span class="string">""</span>, <span class="string">"abc"</span>, <span class="prelude-val">Some</span>(<span class="number">0</span>), <span class="prelude-val">Some</span>(<span class="number">3</span>)), |
| (<span class="string">"a"</span>, <span class="string">""</span>, <span class="prelude-val">None</span>, <span class="prelude-val">None</span>), |
| (<span class="string">"a"</span>, <span class="string">"a"</span>, <span class="prelude-val">Some</span>(<span class="number">0</span>), <span class="prelude-val">Some</span>(<span class="number">0</span>)), |
| (<span class="string">"a"</span>, <span class="string">"aa"</span>, <span class="prelude-val">Some</span>(<span class="number">0</span>), <span class="prelude-val">Some</span>(<span class="number">1</span>)), |
| (<span class="string">"a"</span>, <span class="string">"ba"</span>, <span class="prelude-val">Some</span>(<span class="number">1</span>), <span class="prelude-val">Some</span>(<span class="number">1</span>)), |
| (<span class="string">"a"</span>, <span class="string">"bba"</span>, <span class="prelude-val">Some</span>(<span class="number">2</span>), <span class="prelude-val">Some</span>(<span class="number">2</span>)), |
| (<span class="string">"a"</span>, <span class="string">"bbba"</span>, <span class="prelude-val">Some</span>(<span class="number">3</span>), <span class="prelude-val">Some</span>(<span class="number">3</span>)), |
| (<span class="string">"a"</span>, <span class="string">"bbbab"</span>, <span class="prelude-val">Some</span>(<span class="number">3</span>), <span class="prelude-val">Some</span>(<span class="number">3</span>)), |
| (<span class="string">"a"</span>, <span class="string">"bbbabb"</span>, <span class="prelude-val">Some</span>(<span class="number">3</span>), <span class="prelude-val">Some</span>(<span class="number">3</span>)), |
| (<span class="string">"a"</span>, <span class="string">"bbbabbb"</span>, <span class="prelude-val">Some</span>(<span class="number">3</span>), <span class="prelude-val">Some</span>(<span class="number">3</span>)), |
| (<span class="string">"a"</span>, <span class="string">"bbbbbb"</span>, <span class="prelude-val">None</span>, <span class="prelude-val">None</span>), |
| (<span class="string">"ab"</span>, <span class="string">""</span>, <span class="prelude-val">None</span>, <span class="prelude-val">None</span>), |
| (<span class="string">"ab"</span>, <span class="string">"a"</span>, <span class="prelude-val">None</span>, <span class="prelude-val">None</span>), |
| (<span class="string">"ab"</span>, <span class="string">"b"</span>, <span class="prelude-val">None</span>, <span class="prelude-val">None</span>), |
| (<span class="string">"ab"</span>, <span class="string">"ab"</span>, <span class="prelude-val">Some</span>(<span class="number">0</span>), <span class="prelude-val">Some</span>(<span class="number">0</span>)), |
| (<span class="string">"ab"</span>, <span class="string">"aab"</span>, <span class="prelude-val">Some</span>(<span class="number">1</span>), <span class="prelude-val">Some</span>(<span class="number">1</span>)), |
| (<span class="string">"ab"</span>, <span class="string">"aaab"</span>, <span class="prelude-val">Some</span>(<span class="number">2</span>), <span class="prelude-val">Some</span>(<span class="number">2</span>)), |
| (<span class="string">"ab"</span>, <span class="string">"abaab"</span>, <span class="prelude-val">Some</span>(<span class="number">0</span>), <span class="prelude-val">Some</span>(<span class="number">3</span>)), |
| (<span class="string">"ab"</span>, <span class="string">"baaab"</span>, <span class="prelude-val">Some</span>(<span class="number">3</span>), <span class="prelude-val">Some</span>(<span class="number">3</span>)), |
| (<span class="string">"ab"</span>, <span class="string">"acb"</span>, <span class="prelude-val">None</span>, <span class="prelude-val">None</span>), |
| (<span class="string">"ab"</span>, <span class="string">"abba"</span>, <span class="prelude-val">Some</span>(<span class="number">0</span>), <span class="prelude-val">Some</span>(<span class="number">0</span>)), |
| (<span class="string">"abc"</span>, <span class="string">"ab"</span>, <span class="prelude-val">None</span>, <span class="prelude-val">None</span>), |
| (<span class="string">"abc"</span>, <span class="string">"abc"</span>, <span class="prelude-val">Some</span>(<span class="number">0</span>), <span class="prelude-val">Some</span>(<span class="number">0</span>)), |
| (<span class="string">"abc"</span>, <span class="string">"abcz"</span>, <span class="prelude-val">Some</span>(<span class="number">0</span>), <span class="prelude-val">Some</span>(<span class="number">0</span>)), |
| (<span class="string">"abc"</span>, <span class="string">"abczz"</span>, <span class="prelude-val">Some</span>(<span class="number">0</span>), <span class="prelude-val">Some</span>(<span class="number">0</span>)), |
| (<span class="string">"abc"</span>, <span class="string">"zabc"</span>, <span class="prelude-val">Some</span>(<span class="number">1</span>), <span class="prelude-val">Some</span>(<span class="number">1</span>)), |
| (<span class="string">"abc"</span>, <span class="string">"zzabc"</span>, <span class="prelude-val">Some</span>(<span class="number">2</span>), <span class="prelude-val">Some</span>(<span class="number">2</span>)), |
| (<span class="string">"abc"</span>, <span class="string">"azbc"</span>, <span class="prelude-val">None</span>, <span class="prelude-val">None</span>), |
| (<span class="string">"abc"</span>, <span class="string">"abzc"</span>, <span class="prelude-val">None</span>, <span class="prelude-val">None</span>), |
| (<span class="string">"abczdef"</span>, <span class="string">"abczdefzzzzzzzzzzzzzzzzzzzz"</span>, <span class="prelude-val">Some</span>(<span class="number">0</span>), <span class="prelude-val">Some</span>(<span class="number">0</span>)), |
| (<span class="string">"abczdef"</span>, <span class="string">"zzzzzzzzzzzzzzzzzzzzabczdef"</span>, <span class="prelude-val">Some</span>(<span class="number">20</span>), <span class="prelude-val">Some</span>(<span class="number">20</span>)), |
| (<span class="string">"xyz"</span>, <span class="string">"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaxyz"</span>, <span class="prelude-val">Some</span>(<span class="number">32</span>), <span class="prelude-val">Some</span>(<span class="number">32</span>)), |
| <span class="comment">// Failures caught by quickcheck. |
| </span>(<span class="string">"\u{0}\u{15}"</span>, <span class="string">"\u{0}\u{15}\u{15}\u{0}"</span>, <span class="prelude-val">Some</span>(<span class="number">0</span>), <span class="prelude-val">Some</span>(<span class="number">0</span>)), |
| (<span class="string">"\u{0}\u{1e}"</span>, <span class="string">"\u{1e}\u{0}"</span>, <span class="prelude-val">None</span>, <span class="prelude-val">None</span>), |
| ]; |
| |
| <span class="doccomment">/// Run the substring search tests. `search` should be a closure that |
| /// accepts a haystack and a needle and returns the starting position |
| /// of the first occurrence of needle in the haystack, or `None` if one |
| /// doesn't exist. |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>run_search_tests_fwd( |
| <span class="kw-2">mut </span>search: <span class="kw">impl </span>FnMut(<span class="kw-2">&</span>[u8], <span class="kw-2">&</span>[u8]) -> <span class="prelude-ty">Option</span><usize>, |
| ) { |
| <span class="kw">for </span><span class="kw-2">&</span>(needle, haystack, expected_fwd, <span class="kw">_</span>) <span class="kw">in </span>SEARCH_TESTS { |
| <span class="kw">let </span>(n, h) = (needle.as_bytes(), haystack.as_bytes()); |
| <span class="macro">assert_eq!</span>( |
| expected_fwd, |
| search(h, n), |
| <span class="string">"needle: {:?}, haystack: {:?}, expected: {:?}"</span>, |
| n, |
| h, |
| expected_fwd |
| ); |
| } |
| } |
| |
| <span class="doccomment">/// Run the substring search tests. `search` should be a closure that |
| /// accepts a haystack and a needle and returns the starting position of |
| /// the last occurrence of needle in the haystack, or `None` if one doesn't |
| /// exist. |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>run_search_tests_rev( |
| <span class="kw-2">mut </span>search: <span class="kw">impl </span>FnMut(<span class="kw-2">&</span>[u8], <span class="kw-2">&</span>[u8]) -> <span class="prelude-ty">Option</span><usize>, |
| ) { |
| <span class="kw">for </span><span class="kw-2">&</span>(needle, haystack, <span class="kw">_</span>, expected_rev) <span class="kw">in </span>SEARCH_TESTS { |
| <span class="kw">let </span>(n, h) = (needle.as_bytes(), haystack.as_bytes()); |
| <span class="macro">assert_eq!</span>( |
| expected_rev, |
| search(h, n), |
| <span class="string">"needle: {:?}, haystack: {:?}, expected: {:?}"</span>, |
| n, |
| h, |
| expected_rev |
| ); |
| } |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../" data-current-crate="memchr" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |