diff options
Diffstat (limited to 'src/tests/memchr/mod.rs')
| -rw-r--r-- | src/tests/memchr/mod.rs | 314 |
1 files changed, 307 insertions, 7 deletions
diff --git a/src/tests/memchr/mod.rs b/src/tests/memchr/mod.rs index 79f94ab..0564ad4 100644 --- a/src/tests/memchr/mod.rs +++ b/src/tests/memchr/mod.rs @@ -1,7 +1,307 @@ -#[cfg(all(feature = "std", not(miri)))] -mod iter; -#[cfg(all(feature = "std", not(miri)))] -mod memchr; -mod simple; -#[cfg(all(feature = "std", not(miri)))] -mod testdata; +use alloc::{ + string::{String, ToString}, + vec, + vec::Vec, +}; + +use crate::ext::Byte; + +pub(crate) mod naive; +#[macro_use] +pub(crate) mod prop; + +const SEEDS: &'static [Seed] = &[ + Seed { haystack: "a", needles: &[b'a'], positions: &[0] }, + Seed { haystack: "aa", needles: &[b'a'], positions: &[0, 1] }, + Seed { haystack: "aaa", needles: &[b'a'], positions: &[0, 1, 2] }, + Seed { haystack: "", needles: &[b'a'], positions: &[] }, + Seed { haystack: "z", needles: &[b'a'], positions: &[] }, + Seed { haystack: "zz", needles: &[b'a'], positions: &[] }, + Seed { haystack: "zza", needles: &[b'a'], positions: &[2] }, + Seed { haystack: "zaza", needles: &[b'a'], positions: &[1, 3] }, + Seed { haystack: "zzza", needles: &[b'a'], positions: &[3] }, + Seed { haystack: "\x00a", needles: &[b'a'], positions: &[1] }, + Seed { haystack: "\x00", needles: &[b'\x00'], positions: &[0] }, + Seed { haystack: "\x00\x00", needles: &[b'\x00'], positions: &[0, 1] }, + Seed { haystack: "\x00a\x00", needles: &[b'\x00'], positions: &[0, 2] }, + Seed { haystack: "zzzzzzzzzzzzzzzza", needles: &[b'a'], positions: &[16] }, + Seed { + haystack: "zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzza", + needles: &[b'a'], + positions: &[32], + }, + // two needles (applied to memchr2 + memchr3) + Seed { haystack: "az", needles: &[b'a', b'z'], positions: &[0, 1] }, + Seed { haystack: "az", needles: &[b'a', b'z'], positions: &[0, 1] }, + Seed { haystack: "az", needles: &[b'x', b'y'], positions: &[] }, + Seed { haystack: "az", needles: &[b'a', b'y'], positions: &[0] }, + Seed { haystack: "az", needles: &[b'x', b'z'], positions: &[1] }, + Seed { haystack: "yyyyaz", needles: &[b'a', b'z'], positions: &[4, 5] }, + Seed { haystack: "yyyyaz", needles: &[b'z', b'a'], positions: &[4, 5] }, + // three needles (applied to memchr3) + Seed { + haystack: "xyz", + needles: &[b'x', b'y', b'z'], + positions: &[0, 1, 2], + }, + Seed { + haystack: "zxy", + needles: &[b'x', b'y', b'z'], + positions: &[0, 1, 2], + }, + Seed { haystack: "zxy", needles: &[b'x', b'a', b'z'], positions: &[0, 1] }, + Seed { haystack: "zxy", needles: &[b't', b'a', b'z'], positions: &[0] }, + Seed { haystack: "yxz", needles: &[b't', b'a', b'z'], positions: &[2] }, +]; + +/// Runs a host of substring search tests. +/// +/// This has support for "partial" substring search implementations only work +/// for a subset of needles/haystacks. For example, the "packed pair" substring +/// search implementation only works for haystacks of some minimum length based +/// of the pair of bytes selected and the size of the vector used. +pub(crate) struct Runner { + needle_len: usize, +} + +impl Runner { + /// Create a new test runner for forward and reverse byte search + /// implementations. + /// + /// The `needle_len` given must be at most `3` and at least `1`. It + /// corresponds to the number of needle bytes to search for. + pub(crate) fn new(needle_len: usize) -> Runner { + assert!(needle_len >= 1, "needle_len must be at least 1"); + assert!(needle_len <= 3, "needle_len must be at most 3"); + Runner { needle_len } + } + + /// Run all tests. This panics on the first failure. + /// + /// If the implementation being tested returns `None` for a particular + /// haystack/needle combination, then that test is skipped. + pub(crate) fn forward_iter<F>(self, mut test: F) + where + F: FnMut(&[u8], &[u8]) -> Option<Vec<usize>> + 'static, + { + for seed in SEEDS.iter() { + if seed.needles.len() > self.needle_len { + continue; + } + for t in seed.generate() { + let results = match test(t.haystack.as_bytes(), &t.needles) { + None => continue, + Some(results) => results, + }; + assert_eq!( + t.expected, + results, + "needles: {:?}, haystack: {:?}", + t.needles + .iter() + .map(|&b| b.to_char()) + .collect::<Vec<char>>(), + t.haystack, + ); + } + } + } + + /// Run all tests in the reverse direction. This panics on the first + /// failure. + /// + /// If the implementation being tested returns `None` for a particular + /// haystack/needle combination, then that test is skipped. + pub(crate) fn reverse_iter<F>(self, mut test: F) + where + F: FnMut(&[u8], &[u8]) -> Option<Vec<usize>> + 'static, + { + for seed in SEEDS.iter() { + if seed.needles.len() > self.needle_len { + continue; + } + for t in seed.generate() { + let mut results = match test(t.haystack.as_bytes(), &t.needles) + { + None => continue, + Some(results) => results, + }; + results.reverse(); + assert_eq!( + t.expected, + results, + "needles: {:?}, haystack: {:?}", + t.needles + .iter() + .map(|&b| b.to_char()) + .collect::<Vec<char>>(), + t.haystack, + ); + } + } + } + + /// Run all tests as counting tests. This panics on the first failure. + /// + /// That is, this only checks that the number of matches is correct and + /// not whether the offsets of each match are. + pub(crate) fn count_iter<F>(self, mut test: F) + where + F: FnMut(&[u8], &[u8]) -> Option<usize> + 'static, + { + for seed in SEEDS.iter() { + if seed.needles.len() > self.needle_len { + continue; + } + for t in seed.generate() { + let got = match test(t.haystack.as_bytes(), &t.needles) { + None => continue, + Some(got) => got, + }; + assert_eq!( + t.expected.len(), + got, + "needles: {:?}, haystack: {:?}", + t.needles + .iter() + .map(|&b| b.to_char()) + .collect::<Vec<char>>(), + t.haystack, + ); + } + } + } + + /// Like `Runner::forward`, but for a function that returns only the next + /// match and not all matches. + /// + /// If the function returns `None`, then it is skipped. + pub(crate) fn forward_oneshot<F>(self, mut test: F) + where + F: FnMut(&[u8], &[u8]) -> Option<Option<usize>> + 'static, + { + self.forward_iter(move |haystack, needles| { + let mut start = 0; + let mut results = vec![]; + while let Some(i) = test(&haystack[start..], needles)? { + results.push(start + i); + start += i + 1; + } + Some(results) + }) + } + + /// Like `Runner::reverse`, but for a function that returns only the last + /// match and not all matches. + /// + /// If the function returns `None`, then it is skipped. + pub(crate) fn reverse_oneshot<F>(self, mut test: F) + where + F: FnMut(&[u8], &[u8]) -> Option<Option<usize>> + 'static, + { + self.reverse_iter(move |haystack, needles| { + let mut end = haystack.len(); + let mut results = vec![]; + while let Some(i) = test(&haystack[..end], needles)? { + results.push(i); + end = i; + } + Some(results) + }) + } +} + +/// A single test for memr?chr{,2,3}. +#[derive(Clone, Debug)] +struct Test { + /// The string to search in. + haystack: String, + /// The needles to look for. + needles: Vec<u8>, + /// The offsets that are expected to be found for all needles in the + /// forward direction. + expected: Vec<usize>, +} + +impl Test { + fn new(seed: &Seed) -> Test { + Test { + haystack: seed.haystack.to_string(), + needles: seed.needles.to_vec(), + expected: seed.positions.to_vec(), + } + } +} + +/// Data that can be expanded into many memchr tests by padding out the corpus. +#[derive(Clone, Debug)] +struct Seed { + /// The thing to search. We use `&str` instead of `&[u8]` because they + /// are nicer to write in tests, and we don't miss much since memchr + /// doesn't care about UTF-8. + /// + /// Corpora cannot contain either '%' or '#'. We use these bytes when + /// expanding test cases into many test cases, and we assume they are not + /// used. If they are used, `memchr_tests` will panic. + haystack: &'static str, + /// The needles to search for. This is intended to be an alternation of + /// needles. The number of needles may cause this test to be skipped for + /// some memchr variants. For example, a test with 2 needles cannot be used + /// to test `memchr`, but can be used to test `memchr2` and `memchr3`. + /// However, a test with only 1 needle can be used to test all of `memchr`, + /// `memchr2` and `memchr3`. We achieve this by filling in the needles with + /// bytes that we never used in the corpus (such as '#'). + needles: &'static [u8], + /// The positions expected to match for all of the needles. + positions: &'static [usize], +} + +impl Seed { + /// Controls how much we expand the haystack on either side for each test. + /// We lower this on Miri because otherwise running the tests would take + /// forever. + const EXPAND_LEN: usize = { + #[cfg(not(miri))] + { + 515 + } + #[cfg(miri)] + { + 6 + } + }; + + /// Expand this test into many variations of the same test. + /// + /// In particular, this will generate more tests with larger corpus sizes. + /// The expected positions are updated to maintain the integrity of the + /// test. + /// + /// This is important in testing a memchr implementation, because there are + /// often different cases depending on the length of the corpus. + /// + /// Note that we extend the corpus by adding `%` bytes, which we + /// don't otherwise use as a needle. + fn generate(&self) -> impl Iterator<Item = Test> { + let mut more = vec![]; + + // Add bytes to the start of the corpus. + for i in 0..Seed::EXPAND_LEN { + let mut t = Test::new(self); + let mut new: String = core::iter::repeat('%').take(i).collect(); + new.push_str(&t.haystack); + t.haystack = new; + t.expected = t.expected.into_iter().map(|p| p + i).collect(); + more.push(t); + } + // Add bytes to the end of the corpus. + for i in 1..Seed::EXPAND_LEN { + let mut t = Test::new(self); + let padding: String = core::iter::repeat('%').take(i).collect(); + t.haystack.push_str(&padding); + more.push(t); + } + + more.into_iter() + } +} |