Vendor dependencies for 0.3.0 release

vendor/memchr/src/tests/memchr/mod.rs

@@ -0,0 +1,307 @@
+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()
+    }
+}

vendor/memchr/src/tests/memchr/naive.rs

@@ -0,0 +1,33 @@
+pub(crate) fn memchr(n1: u8, haystack: &[u8]) -> Option<usize> {
+    haystack.iter().position(|&b| b == n1)
+}
+
+pub(crate) fn memchr2(n1: u8, n2: u8, haystack: &[u8]) -> Option<usize> {
+    haystack.iter().position(|&b| b == n1 || b == n2)
+}
+
+pub(crate) fn memchr3(
+    n1: u8,
+    n2: u8,
+    n3: u8,
+    haystack: &[u8],
+) -> Option<usize> {
+    haystack.iter().position(|&b| b == n1 || b == n2 || b == n3)
+}
+
+pub(crate) fn memrchr(n1: u8, haystack: &[u8]) -> Option<usize> {
+    haystack.iter().rposition(|&b| b == n1)
+}
+
+pub(crate) fn memrchr2(n1: u8, n2: u8, haystack: &[u8]) -> Option<usize> {
+    haystack.iter().rposition(|&b| b == n1 || b == n2)
+}
+
+pub(crate) fn memrchr3(
+    n1: u8,
+    n2: u8,
+    n3: u8,
+    haystack: &[u8],
+) -> Option<usize> {
+    haystack.iter().rposition(|&b| b == n1 || b == n2 || b == n3)
+}

vendor/memchr/src/tests/memchr/prop.rs

@@ -0,0 +1,323 @@
+/// Defines a host of quickcheck tests for the given memchr searcher.
+#[cfg(miri)]
+#[macro_export]
+macro_rules! define_memchr_quickcheck {
+    ($($tt:tt)*) => {};
+}
+
+/// Defines a host of quickcheck tests for the given memchr searcher.
+#[cfg(not(miri))]
+#[macro_export]
+macro_rules! define_memchr_quickcheck {
+    ($mod:ident) => {
+        define_memchr_quickcheck!($mod, new);
+    };
+    ($mod:ident, $cons:ident) => {
+        use alloc::vec::Vec;
+
+        use quickcheck::TestResult;
+
+        use crate::tests::memchr::{
+            naive,
+            prop::{double_ended_take, naive1_iter, naive2_iter, naive3_iter},
+        };
+
+        quickcheck::quickcheck! {
+            fn qc_memchr_matches_naive(n1: u8, corpus: Vec<u8>) -> TestResult {
+                let expected = naive::memchr(n1, &corpus);
+                let got = match $mod::One::$cons(n1) {
+                    None => return TestResult::discard(),
+                    Some(f) => f.find(&corpus),
+                };
+                TestResult::from_bool(expected == got)
+            }
+
+            fn qc_memrchr_matches_naive(n1: u8, corpus: Vec<u8>) -> TestResult {
+                let expected = naive::memrchr(n1, &corpus);
+                let got = match $mod::One::$cons(n1) {
+                    None => return TestResult::discard(),
+                    Some(f) => f.rfind(&corpus),
+                };
+                TestResult::from_bool(expected == got)
+            }
+
+            fn qc_memchr2_matches_naive(n1: u8, n2: u8, corpus: Vec<u8>) -> TestResult {
+                let expected = naive::memchr2(n1, n2, &corpus);
+                let got = match $mod::Two::$cons(n1, n2) {
+                    None => return TestResult::discard(),
+                    Some(f) => f.find(&corpus),
+                };
+                TestResult::from_bool(expected == got)
+            }
+
+            fn qc_memrchr2_matches_naive(n1: u8, n2: u8, corpus: Vec<u8>) -> TestResult {
+                let expected = naive::memrchr2(n1, n2, &corpus);
+                let got = match $mod::Two::$cons(n1, n2) {
+                    None => return TestResult::discard(),
+                    Some(f) => f.rfind(&corpus),
+                };
+                TestResult::from_bool(expected == got)
+            }
+
+            fn qc_memchr3_matches_naive(
+                n1: u8, n2: u8, n3: u8,
+                corpus: Vec<u8>
+            ) -> TestResult {
+                let expected = naive::memchr3(n1, n2, n3, &corpus);
+                let got = match $mod::Three::$cons(n1, n2, n3) {
+                    None => return TestResult::discard(),
+                    Some(f) => f.find(&corpus),
+                };
+                TestResult::from_bool(expected == got)
+            }
+
+            fn qc_memrchr3_matches_naive(
+                n1: u8, n2: u8, n3: u8,
+                corpus: Vec<u8>
+            ) -> TestResult {
+                let expected = naive::memrchr3(n1, n2, n3, &corpus);
+                let got = match $mod::Three::$cons(n1, n2, n3) {
+                    None => return TestResult::discard(),
+                    Some(f) => f.rfind(&corpus),
+                };
+                TestResult::from_bool(expected == got)
+            }
+
+            fn qc_memchr_double_ended_iter(
+                needle: u8, data: Vec<u8>, take_side: Vec<bool>
+            ) -> TestResult {
+                // make nonempty
+                let mut take_side = take_side;
+                if take_side.is_empty() { take_side.push(true) };
+
+                let finder = match $mod::One::$cons(needle) {
+                    None => return TestResult::discard(),
+                    Some(finder) => finder,
+                };
+                let iter = finder.iter(&data);
+                let got = double_ended_take(
+                    iter,
+                    take_side.iter().cycle().cloned(),
+                );
+                let expected = naive1_iter(needle, &data);
+
+                TestResult::from_bool(got.iter().cloned().eq(expected))
+            }
+
+            fn qc_memchr2_double_ended_iter(
+                needle1: u8, needle2: u8, data: Vec<u8>, take_side: Vec<bool>
+            ) -> TestResult {
+                // make nonempty
+                let mut take_side = take_side;
+                if take_side.is_empty() { take_side.push(true) };
+
+                let finder = match $mod::Two::$cons(needle1, needle2) {
+                    None => return TestResult::discard(),
+                    Some(finder) => finder,
+                };
+                let iter = finder.iter(&data);
+                let got = double_ended_take(
+                    iter,
+                    take_side.iter().cycle().cloned(),
+                );
+                let expected = naive2_iter(needle1, needle2, &data);
+
+                TestResult::from_bool(got.iter().cloned().eq(expected))
+            }
+
+            fn qc_memchr3_double_ended_iter(
+                needle1: u8, needle2: u8, needle3: u8,
+                data: Vec<u8>, take_side: Vec<bool>
+            ) -> TestResult {
+                // make nonempty
+                let mut take_side = take_side;
+                if take_side.is_empty() { take_side.push(true) };
+
+                let finder = match $mod::Three::$cons(needle1, needle2, needle3) {
+                    None => return TestResult::discard(),
+                    Some(finder) => finder,
+                };
+                let iter = finder.iter(&data);
+                let got = double_ended_take(
+                    iter,
+                    take_side.iter().cycle().cloned(),
+                );
+                let expected = naive3_iter(needle1, needle2, needle3, &data);
+
+                TestResult::from_bool(got.iter().cloned().eq(expected))
+            }
+
+            fn qc_memchr1_iter(data: Vec<u8>) -> TestResult {
+                let needle = 0;
+                let finder = match $mod::One::$cons(needle) {
+                    None => return TestResult::discard(),
+                    Some(finder) => finder,
+                };
+                let got = finder.iter(&data);
+                let expected = naive1_iter(needle, &data);
+                TestResult::from_bool(got.eq(expected))
+            }
+
+            fn qc_memchr1_rev_iter(data: Vec<u8>) -> TestResult {
+                let needle = 0;
+
+                let finder = match $mod::One::$cons(needle) {
+                    None => return TestResult::discard(),
+                    Some(finder) => finder,
+                };
+                let got = finder.iter(&data).rev();
+                let expected = naive1_iter(needle, &data).rev();
+                TestResult::from_bool(got.eq(expected))
+            }
+
+            fn qc_memchr2_iter(data: Vec<u8>) -> TestResult {
+                let needle1 = 0;
+                let needle2 = 1;
+
+                let finder = match $mod::Two::$cons(needle1, needle2) {
+                    None => return TestResult::discard(),
+                    Some(finder) => finder,
+                };
+                let got = finder.iter(&data);
+                let expected = naive2_iter(needle1, needle2, &data);
+                TestResult::from_bool(got.eq(expected))
+            }
+
+            fn qc_memchr2_rev_iter(data: Vec<u8>) -> TestResult {
+                let needle1 = 0;
+                let needle2 = 1;
+
+                let finder = match $mod::Two::$cons(needle1, needle2) {
+                    None => return TestResult::discard(),
+                    Some(finder) => finder,
+                };
+                let got = finder.iter(&data).rev();
+                let expected = naive2_iter(needle1, needle2, &data).rev();
+                TestResult::from_bool(got.eq(expected))
+            }
+
+            fn qc_memchr3_iter(data: Vec<u8>) -> TestResult {
+                let needle1 = 0;
+                let needle2 = 1;
+                let needle3 = 2;
+
+                let finder = match $mod::Three::$cons(needle1, needle2, needle3) {
+                    None => return TestResult::discard(),
+                    Some(finder) => finder,
+                };
+                let got = finder.iter(&data);
+                let expected = naive3_iter(needle1, needle2, needle3, &data);
+                TestResult::from_bool(got.eq(expected))
+            }
+
+            fn qc_memchr3_rev_iter(data: Vec<u8>) -> TestResult {
+                let needle1 = 0;
+                let needle2 = 1;
+                let needle3 = 2;
+
+                let finder = match $mod::Three::$cons(needle1, needle2, needle3) {
+                    None => return TestResult::discard(),
+                    Some(finder) => finder,
+                };
+                let got = finder.iter(&data).rev();
+                let expected = naive3_iter(needle1, needle2, needle3, &data).rev();
+                TestResult::from_bool(got.eq(expected))
+            }
+
+            fn qc_memchr1_iter_size_hint(data: Vec<u8>) -> TestResult {
+                // test that the size hint is within reasonable bounds
+                let needle = 0;
+                let finder = match $mod::One::$cons(needle) {
+                    None => return TestResult::discard(),
+                    Some(finder) => finder,
+                };
+                let mut iter = finder.iter(&data);
+                let mut real_count = data
+                    .iter()
+                    .filter(|&&elt| elt == needle)
+                    .count();
+
+                while let Some(index) = iter.next() {
+                    real_count -= 1;
+                    let (lower, upper) = iter.size_hint();
+                    assert!(lower <= real_count);
+                    assert!(upper.unwrap() >= real_count);
+                    assert!(upper.unwrap() <= data.len() - index);
+                }
+                TestResult::passed()
+            }
+        }
+    };
+}
+
+// take items from a DEI, taking front for each true and back for each false.
+// Return a vector with the concatenation of the fronts and the reverse of the
+// backs.
+#[cfg(not(miri))]
+pub(crate) fn double_ended_take<I, J>(
+    mut iter: I,
+    take_side: J,
+) -> alloc::vec::Vec<I::Item>
+where
+    I: DoubleEndedIterator,
+    J: Iterator<Item = bool>,
+{
+    let mut found_front = alloc::vec![];
+    let mut found_back = alloc::vec![];
+
+    for take_front in take_side {
+        if take_front {
+            if let Some(pos) = iter.next() {
+                found_front.push(pos);
+            } else {
+                break;
+            }
+        } else {
+            if let Some(pos) = iter.next_back() {
+                found_back.push(pos);
+            } else {
+                break;
+            }
+        };
+    }
+
+    let mut all_found = found_front;
+    all_found.extend(found_back.into_iter().rev());
+    all_found
+}
+
+// return an iterator of the 0-based indices of haystack that match the needle
+#[cfg(not(miri))]
+pub(crate) fn naive1_iter<'a>(
+    n1: u8,
+    haystack: &'a [u8],
+) -> impl DoubleEndedIterator<Item = usize> + 'a {
+    haystack.iter().enumerate().filter(move |&(_, &b)| b == n1).map(|t| t.0)
+}
+
+#[cfg(not(miri))]
+pub(crate) fn naive2_iter<'a>(
+    n1: u8,
+    n2: u8,
+    haystack: &'a [u8],
+) -> impl DoubleEndedIterator<Item = usize> + 'a {
+    haystack
+        .iter()
+        .enumerate()
+        .filter(move |&(_, &b)| b == n1 || b == n2)
+        .map(|t| t.0)
+}
+
+#[cfg(not(miri))]
+pub(crate) fn naive3_iter<'a>(
+    n1: u8,
+    n2: u8,
+    n3: u8,
+    haystack: &'a [u8],
+) -> impl DoubleEndedIterator<Item = usize> + 'a {
+    haystack
+        .iter()
+        .enumerate()
+        .filter(move |&(_, &b)| b == n1 || b == n2 || b == n3)
+        .map(|t| t.0)
+}

vendor/memchr/src/tests/mod.rs

@@ -0,0 +1,15 @@
+#[macro_use]
+pub(crate) mod memchr;
+pub(crate) mod packedpair;
+#[macro_use]
+pub(crate) mod substring;
+
+// For debugging, particularly in CI, print out the byte order of the current
+// target.
+#[test]
+fn byte_order() {
+    #[cfg(target_endian = "little")]
+    std::eprintln!("LITTLE ENDIAN");
+    #[cfg(target_endian = "big")]
+    std::eprintln!("BIG ENDIAN");
+}

vendor/memchr/src/tests/packedpair.rs

@@ -0,0 +1,216 @@
+use alloc::{boxed::Box, vec, vec::Vec};
+
+/// A set of "packed pair" test seeds. Each seed serves as the base for the
+/// generation of many other tests. In essence, the seed captures the pair of
+/// bytes we used for a predicate and first byte among our needle. The tests
+/// generated from each seed essentially vary the length of the needle and
+/// haystack, while using the rare/first byte configuration from the seed.
+///
+/// The purpose of this is to test many different needle/haystack lengths.
+/// In particular, some of the vector optimizations might only have bugs
+/// in haystacks of a certain size.
+const SEEDS: &[Seed] = &[
+    // Why not use different 'first' bytes? It seemed like a good idea to be
+    // able to configure it, but when I wrote the test generator below, it
+    // didn't seem necessary to use for reasons that I forget.
+    Seed { first: b'x', index1: b'y', index2: b'z' },
+    Seed { first: b'x', index1: b'x', index2: b'z' },
+    Seed { first: b'x', index1: b'y', index2: b'x' },
+    Seed { first: b'x', index1: b'x', index2: b'x' },
+    Seed { first: b'x', index1: b'y', index2: b'y' },
+];
+
+/// Runs a host of "packed pair" search tests.
+///
+/// These tests specifically look for the occurrence of a possible substring
+/// match based on a pair of bytes matching at the right offsets.
+pub(crate) struct Runner {
+    fwd: Option<
+        Box<
+            dyn FnMut(&[u8], &[u8], u8, u8) -> Option<Option<usize>> + 'static,
+        >,
+    >,
+}
+
+impl Runner {
+    /// Create a new test runner for "packed pair" substring search.
+    pub(crate) fn new() -> Runner {
+        Runner { fwd: None }
+    }
+
+    /// 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.
+    ///
+    /// This runs tests on both the forward and reverse implementations given.
+    /// If either (or both) are missing, then tests for that implementation are
+    /// skipped.
+    pub(crate) fn run(self) {
+        if let Some(mut fwd) = self.fwd {
+            for seed in SEEDS.iter() {
+                for t in seed.generate() {
+                    match fwd(&t.haystack, &t.needle, t.index1, t.index2) {
+                        None => continue,
+                        Some(result) => {
+                            assert_eq!(
+                                t.fwd, result,
+                                "FORWARD, needle: {:?}, haystack: {:?}, \
+                                 index1: {:?}, index2: {:?}",
+                                t.needle, t.haystack, t.index1, t.index2,
+                            )
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    /// Set the implementation for forward "packed pair" substring search.
+    ///
+    /// If the closure returns `None`, then it is assumed that the given
+    /// test cannot be applied to the particular implementation and it is
+    /// skipped. For example, if a particular implementation only supports
+    /// needles or haystacks for some minimum length.
+    ///
+    /// If this is not set, then forward "packed pair" search is not tested.
+    pub(crate) fn fwd(
+        mut self,
+        search: impl FnMut(&[u8], &[u8], u8, u8) -> Option<Option<usize>> + 'static,
+    ) -> Runner {
+        self.fwd = Some(Box::new(search));
+        self
+    }
+}
+
+/// A test that represents the input and expected output to a "packed pair"
+/// search function. The test should be able to run with any "packed pair"
+/// implementation and get the expected output.
+struct Test {
+    haystack: Vec<u8>,
+    needle: Vec<u8>,
+    index1: u8,
+    index2: u8,
+    fwd: Option<usize>,
+}
+
+impl Test {
+    /// Create a new "packed pair" test from a seed and some given offsets to
+    /// the pair of bytes to use as a predicate in the seed's needle.
+    ///
+    /// If a valid test could not be constructed, then None is returned.
+    /// (Currently, we take the approach of massaging tests to be valid
+    /// instead of rejecting them outright.)
+    fn new(
+        seed: Seed,
+        index1: usize,
+        index2: usize,
+        haystack_len: usize,
+        needle_len: usize,
+        fwd: Option<usize>,
+    ) -> Option<Test> {
+        let mut index1: u8 = index1.try_into().unwrap();
+        let mut index2: u8 = index2.try_into().unwrap();
+        // The '#' byte is never used in a haystack (unless we're expecting
+        // a match), while the '@' byte is never used in a needle.
+        let mut haystack = vec![b'@'; haystack_len];
+        let mut needle = vec![b'#'; needle_len];
+        needle[0] = seed.first;
+        needle[index1 as usize] = seed.index1;
+        needle[index2 as usize] = seed.index2;
+        // If we're expecting a match, then make sure the needle occurs
+        // in the haystack at the expected position.
+        if let Some(i) = fwd {
+            haystack[i..i + needle.len()].copy_from_slice(&needle);
+        }
+        // If the operations above lead to rare offsets pointing to the
+        // non-first occurrence of a byte, then adjust it. This might lead
+        // to redundant tests, but it's simpler than trying to change the
+        // generation process I think.
+        if let Some(i) = crate::memchr(seed.index1, &needle) {
+            index1 = u8::try_from(i).unwrap();
+        }
+        if let Some(i) = crate::memchr(seed.index2, &needle) {
+            index2 = u8::try_from(i).unwrap();
+        }
+        Some(Test { haystack, needle, index1, index2, fwd })
+    }
+}
+
+/// Data that describes a single prefilter test seed.
+#[derive(Clone, Copy)]
+struct Seed {
+    first: u8,
+    index1: u8,
+    index2: u8,
+}
+
+impl Seed {
+    const NEEDLE_LENGTH_LIMIT: usize = {
+        #[cfg(not(miri))]
+        {
+            33
+        }
+        #[cfg(miri)]
+        {
+            5
+        }
+    };
+
+    const HAYSTACK_LENGTH_LIMIT: usize = {
+        #[cfg(not(miri))]
+        {
+            65
+        }
+        #[cfg(miri)]
+        {
+            8
+        }
+    };
+
+    /// Generate a series of prefilter tests from this seed.
+    fn generate(self) -> impl Iterator<Item = Test> {
+        let len_start = 2;
+        // The iterator below generates *a lot* of tests. The number of
+        // tests was chosen somewhat empirically to be "bearable" when
+        // running the test suite.
+        //
+        // We use an iterator here because the collective haystacks of all
+        // these test cases add up to enough memory to OOM a conservative
+        // sandbox or a small laptop.
+        (len_start..=Seed::NEEDLE_LENGTH_LIMIT).flat_map(move |needle_len| {
+            let index_start = len_start - 1;
+            (index_start..needle_len).flat_map(move |index1| {
+                (index1..needle_len).flat_map(move |index2| {
+                    (needle_len..=Seed::HAYSTACK_LENGTH_LIMIT).flat_map(
+                        move |haystack_len| {
+                            Test::new(
+                                self,
+                                index1,
+                                index2,
+                                haystack_len,
+                                needle_len,
+                                None,
+                            )
+                            .into_iter()
+                            .chain(
+                                (0..=(haystack_len - needle_len)).flat_map(
+                                    move |output| {
+                                        Test::new(
+                                            self,
+                                            index1,
+                                            index2,
+                                            haystack_len,
+                                            needle_len,
+                                            Some(output),
+                                        )
+                                    },
+                                ),
+                            )
+                        },
+                    )
+                })
+            })
+        })
+    }
+}

vendor/memchr/src/tests/substring/mod.rs

@@ -0,0 +1,232 @@
+/*!
+This module defines tests and test helpers for substring implementations.
+*/
+
+use alloc::{
+    boxed::Box,
+    format,
+    string::{String, ToString},
+};
+
+pub(crate) mod naive;
+#[macro_use]
+pub(crate) mod prop;
+
+const SEEDS: &'static [Seed] = &[
+    Seed::new("", "", Some(0), Some(0)),
+    Seed::new("", "a", Some(0), Some(1)),
+    Seed::new("", "ab", Some(0), Some(2)),
+    Seed::new("", "abc", Some(0), Some(3)),
+    Seed::new("a", "", None, None),
+    Seed::new("a", "a", Some(0), Some(0)),
+    Seed::new("a", "aa", Some(0), Some(1)),
+    Seed::new("a", "ba", Some(1), Some(1)),
+    Seed::new("a", "bba", Some(2), Some(2)),
+    Seed::new("a", "bbba", Some(3), Some(3)),
+    Seed::new("a", "bbbab", Some(3), Some(3)),
+    Seed::new("a", "bbbabb", Some(3), Some(3)),
+    Seed::new("a", "bbbabbb", Some(3), Some(3)),
+    Seed::new("a", "bbbbbb", None, None),
+    Seed::new("ab", "", None, None),
+    Seed::new("ab", "a", None, None),
+    Seed::new("ab", "b", None, None),
+    Seed::new("ab", "ab", Some(0), Some(0)),
+    Seed::new("ab", "aab", Some(1), Some(1)),
+    Seed::new("ab", "aaab", Some(2), Some(2)),
+    Seed::new("ab", "abaab", Some(0), Some(3)),
+    Seed::new("ab", "baaab", Some(3), Some(3)),
+    Seed::new("ab", "acb", None, None),
+    Seed::new("ab", "abba", Some(0), Some(0)),
+    Seed::new("abc", "ab", None, None),
+    Seed::new("abc", "abc", Some(0), Some(0)),
+    Seed::new("abc", "abcz", Some(0), Some(0)),
+    Seed::new("abc", "abczz", Some(0), Some(0)),
+    Seed::new("abc", "zabc", Some(1), Some(1)),
+    Seed::new("abc", "zzabc", Some(2), Some(2)),
+    Seed::new("abc", "azbc", None, None),
+    Seed::new("abc", "abzc", None, None),
+    Seed::new("abczdef", "abczdefzzzzzzzzzzzzzzzzzzzz", Some(0), Some(0)),
+    Seed::new("abczdef", "zzzzzzzzzzzzzzzzzzzzabczdef", Some(20), Some(20)),
+    Seed::new(
+        "xyz",
+        "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaxyz",
+        Some(32),
+        Some(32),
+    ),
+    Seed::new("\u{0}\u{15}", "\u{0}\u{15}\u{15}\u{0}", Some(0), Some(0)),
+    Seed::new("\u{0}\u{1e}", "\u{1e}\u{0}", None, None),
+];
+
+/// 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 {
+    fwd: Option<
+        Box<dyn FnMut(&[u8], &[u8]) -> Option<Option<usize>> + 'static>,
+    >,
+    rev: Option<
+        Box<dyn FnMut(&[u8], &[u8]) -> Option<Option<usize>> + 'static>,
+    >,
+}
+
+impl Runner {
+    /// Create a new test runner for forward and reverse substring search
+    /// implementations.
+    pub(crate) fn new() -> Runner {
+        Runner { fwd: None, rev: None }
+    }
+
+    /// 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.
+    ///
+    /// This runs tests on both the forward and reverse implementations given.
+    /// If either (or both) are missing, then tests for that implementation are
+    /// skipped.
+    pub(crate) fn run(self) {
+        if let Some(mut fwd) = self.fwd {
+            for seed in SEEDS.iter() {
+                for t in seed.generate() {
+                    match fwd(t.haystack.as_bytes(), t.needle.as_bytes()) {
+                        None => continue,
+                        Some(result) => {
+                            assert_eq!(
+                                t.fwd, result,
+                                "FORWARD, needle: {:?}, haystack: {:?}",
+                                t.needle, t.haystack,
+                            );
+                        }
+                    }
+                }
+            }
+        }
+        if let Some(mut rev) = self.rev {
+            for seed in SEEDS.iter() {
+                for t in seed.generate() {
+                    match rev(t.haystack.as_bytes(), t.needle.as_bytes()) {
+                        None => continue,
+                        Some(result) => {
+                            assert_eq!(
+                                t.rev, result,
+                                "REVERSE, needle: {:?}, haystack: {:?}",
+                                t.needle, t.haystack,
+                            );
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    /// Set the implementation for forward substring search.
+    ///
+    /// If the closure returns `None`, then it is assumed that the given
+    /// test cannot be applied to the particular implementation and it is
+    /// skipped. For example, if a particular implementation only supports
+    /// needles or haystacks for some minimum length.
+    ///
+    /// If this is not set, then forward substring search is not tested.
+    pub(crate) fn fwd(
+        mut self,
+        search: impl FnMut(&[u8], &[u8]) -> Option<Option<usize>> + 'static,
+    ) -> Runner {
+        self.fwd = Some(Box::new(search));
+        self
+    }
+
+    /// Set the implementation for reverse substring search.
+    ///
+    /// If the closure returns `None`, then it is assumed that the given
+    /// test cannot be applied to the particular implementation and it is
+    /// skipped. For example, if a particular implementation only supports
+    /// needles or haystacks for some minimum length.
+    ///
+    /// If this is not set, then reverse substring search is not tested.
+    pub(crate) fn rev(
+        mut self,
+        search: impl FnMut(&[u8], &[u8]) -> Option<Option<usize>> + 'static,
+    ) -> Runner {
+        self.rev = Some(Box::new(search));
+        self
+    }
+}
+
+/// A single substring test for forward and reverse searches.
+#[derive(Clone, Debug)]
+struct Test {
+    needle: String,
+    haystack: String,
+    fwd: Option<usize>,
+    rev: Option<usize>,
+}
+
+/// A single substring test for forward and reverse searches.
+///
+/// Each seed is valid on its own, but it also serves as a starting point
+/// to generate more tests. Namely, we pad out the haystacks with other
+/// characters so that we get more complete coverage. This is especially useful
+/// for testing vector algorithms that tend to have weird special cases for
+/// alignment and loop unrolling.
+///
+/// Padding works by assuming certain characters never otherwise appear in a
+/// needle or a haystack. Neither should contain a `#` character.
+#[derive(Clone, Copy, Debug)]
+struct Seed {
+    needle: &'static str,
+    haystack: &'static str,
+    fwd: Option<usize>,
+    rev: Option<usize>,
+}
+
+impl Seed {
+    const MAX_PAD: usize = 34;
+
+    const fn new(
+        needle: &'static str,
+        haystack: &'static str,
+        fwd: Option<usize>,
+        rev: Option<usize>,
+    ) -> Seed {
+        Seed { needle, haystack, fwd, rev }
+    }
+
+    fn generate(self) -> impl Iterator<Item = Test> {
+        assert!(!self.needle.contains('#'), "needle must not contain '#'");
+        assert!(!self.haystack.contains('#'), "haystack must not contain '#'");
+        (0..=Seed::MAX_PAD)
+            // Generate tests for padding at the beginning of haystack.
+            .map(move |pad| {
+                let needle = self.needle.to_string();
+                let prefix = "#".repeat(pad);
+                let haystack = format!("{}{}", prefix, self.haystack);
+                let fwd = if needle.is_empty() {
+                    Some(0)
+                } else {
+                    self.fwd.map(|i| pad + i)
+                };
+                let rev = if needle.is_empty() {
+                    Some(haystack.len())
+                } else {
+                    self.rev.map(|i| pad + i)
+                };
+                Test { needle, haystack, fwd, rev }
+            })
+            // Generate tests for padding at the end of haystack.
+            .chain((1..=Seed::MAX_PAD).map(move |pad| {
+                let needle = self.needle.to_string();
+                let suffix = "#".repeat(pad);
+                let haystack = format!("{}{}", self.haystack, suffix);
+                let fwd = if needle.is_empty() { Some(0) } else { self.fwd };
+                let rev = if needle.is_empty() {
+                    Some(haystack.len())
+                } else {
+                    self.rev
+                };
+                Test { needle, haystack, fwd, rev }
+            }))
+    }
+}

vendor/memchr/src/tests/substring/naive.rs

@@ -0,0 +1,45 @@
+/*!
+This module defines "naive" implementations of substring search.
+
+These are sometimes useful to compare with "real" substring implementations.
+The idea is that they are so simple that they are unlikely to be incorrect.
+*/
+
+/// Naively search forwards for the given needle in the given haystack.
+pub(crate) fn find(haystack: &[u8], needle: &[u8]) -> Option<usize> {
+    let end = haystack.len().checked_sub(needle.len()).map_or(0, |i| i + 1);
+    for i in 0..end {
+        if needle == &haystack[i..i + needle.len()] {
+            return Some(i);
+        }
+    }
+    None
+}
+
+/// Naively search in reverse for the given needle in the given haystack.
+pub(crate) fn rfind(haystack: &[u8], needle: &[u8]) -> Option<usize> {
+    let end = haystack.len().checked_sub(needle.len()).map_or(0, |i| i + 1);
+    for i in (0..end).rev() {
+        if needle == &haystack[i..i + needle.len()] {
+            return Some(i);
+        }
+    }
+    None
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::substring;
+
+    use super::*;
+
+    #[test]
+    fn forward() {
+        substring::Runner::new().fwd(|h, n| Some(find(h, n))).run()
+    }
+
+    #[test]
+    fn reverse() {
+        substring::Runner::new().rev(|h, n| Some(rfind(h, n))).run()
+    }
+}

vendor/memchr/src/tests/substring/prop.rs

@@ -0,0 +1,126 @@
+/*!
+This module defines a few quickcheck properties for substring search.
+
+It also provides a forward and reverse macro for conveniently defining
+quickcheck tests that run these properties over any substring search
+implementation.
+*/
+
+use crate::tests::substring::naive;
+
+/// $fwd is a `impl FnMut(haystack, needle) -> Option<Option<usize>>`. When the
+/// routine returns `None`, then it's skipped, which is useful for substring
+/// implementations that don't work for all inputs.
+#[macro_export]
+macro_rules! define_substring_forward_quickcheck {
+    ($fwd:expr) => {
+        #[cfg(not(miri))]
+        quickcheck::quickcheck! {
+            fn qc_fwd_prefix_is_substring(bs: alloc::vec::Vec<u8>) -> bool {
+                crate::tests::substring::prop::prefix_is_substring(&bs, $fwd)
+            }
+
+            fn qc_fwd_suffix_is_substring(bs: alloc::vec::Vec<u8>) -> bool {
+                crate::tests::substring::prop::suffix_is_substring(&bs, $fwd)
+            }
+
+            fn qc_fwd_matches_naive(
+                haystack: alloc::vec::Vec<u8>,
+                needle: alloc::vec::Vec<u8>
+            ) -> bool {
+                crate::tests::substring::prop::same_as_naive(
+                    false,
+                    &haystack,
+                    &needle,
+                    $fwd,
+                )
+            }
+        }
+    };
+}
+
+/// $rev is a `impl FnMut(haystack, needle) -> Option<Option<usize>>`. When the
+/// routine returns `None`, then it's skipped, which is useful for substring
+/// implementations that don't work for all inputs.
+#[macro_export]
+macro_rules! define_substring_reverse_quickcheck {
+    ($rev:expr) => {
+        #[cfg(not(miri))]
+        quickcheck::quickcheck! {
+            fn qc_rev_prefix_is_substring(bs: alloc::vec::Vec<u8>) -> bool {
+                crate::tests::substring::prop::prefix_is_substring(&bs, $rev)
+            }
+
+            fn qc_rev_suffix_is_substring(bs: alloc::vec::Vec<u8>) -> bool {
+                crate::tests::substring::prop::suffix_is_substring(&bs, $rev)
+            }
+
+            fn qc_rev_matches_naive(
+                haystack: alloc::vec::Vec<u8>,
+                needle: alloc::vec::Vec<u8>
+            ) -> bool {
+                crate::tests::substring::prop::same_as_naive(
+                    true,
+                    &haystack,
+                    &needle,
+                    $rev,
+                )
+            }
+        }
+    };
+}
+
+/// Check that every prefix of the given byte string is a substring.
+pub(crate) fn prefix_is_substring(
+    bs: &[u8],
+    mut search: impl FnMut(&[u8], &[u8]) -> Option<Option<usize>>,
+) -> bool {
+    for i in 0..bs.len().saturating_sub(1) {
+        let prefix = &bs[..i];
+        let result = match search(bs, prefix) {
+            None => continue,
+            Some(result) => result,
+        };
+        if !result.is_some() {
+            return false;
+        }
+    }
+    true
+}
+
+/// Check that every suffix of the given byte string is a substring.
+pub(crate) fn suffix_is_substring(
+    bs: &[u8],
+    mut search: impl FnMut(&[u8], &[u8]) -> Option<Option<usize>>,
+) -> bool {
+    for i in 0..bs.len().saturating_sub(1) {
+        let suffix = &bs[i..];
+        let result = match search(bs, suffix) {
+            None => continue,
+            Some(result) => result,
+        };
+        if !result.is_some() {
+            return false;
+        }
+    }
+    true
+}
+
+/// Check that naive substring search matches the result of the given search
+/// algorithm.
+pub(crate) fn same_as_naive(
+    reverse: bool,
+    haystack: &[u8],
+    needle: &[u8],
+    mut search: impl FnMut(&[u8], &[u8]) -> Option<Option<usize>>,
+) -> bool {
+    let result = match search(haystack, needle) {
+        None => return true,
+        Some(result) => result,
+    };
+    if reverse {
+        result == naive::rfind(haystack, needle)
+    } else {
+        result == naive::find(haystack, needle)
+    }
+}