Initial vendor packages

Signed-off-by: Valentin Popov <valentin@popov.link>

1 files changed, 216 insertions, 0 deletions

diff --git a/vendor/memchr/src/tests/packedpair.rs b/vendor/memchr/src/tests/packedpair.rs
new file mode 100644
index 0000000..204635b
--- /dev/null
+++ b/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),
+                                        )
+                                    },
+                                ),
+                            )
+                        },
+                    )
+                })
+            })
+        })
+    }
+}