diff options
Diffstat (limited to 'vendor/memchr/src/memmem/x86/sse.rs')
-rw-r--r-- | vendor/memchr/src/memmem/x86/sse.rs | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/vendor/memchr/src/memmem/x86/sse.rs b/vendor/memchr/src/memmem/x86/sse.rs new file mode 100644 index 000000000..22e7d9933 --- /dev/null +++ b/vendor/memchr/src/memmem/x86/sse.rs @@ -0,0 +1,89 @@ +use core::arch::x86_64::__m128i; + +use crate::memmem::{genericsimd, NeedleInfo}; + +/// An SSE accelerated vectorized substring search routine that only works on +/// small needles. +#[derive(Clone, Copy, Debug)] +pub(crate) struct Forward(genericsimd::Forward); + +impl Forward { + /// Create a new "generic simd" forward searcher. If one could not be + /// created from the given inputs, then None is returned. + pub(crate) fn new(ninfo: &NeedleInfo, needle: &[u8]) -> Option<Forward> { + if !cfg!(memchr_runtime_sse2) { + return None; + } + genericsimd::Forward::new(ninfo, needle).map(Forward) + } + + /// Returns the minimum length of haystack that is needed for this searcher + /// to work. Passing a haystack with a length smaller than this will cause + /// `find` to panic. + #[inline(always)] + pub(crate) fn min_haystack_len(&self) -> usize { + self.0.min_haystack_len::<__m128i>() + } + + #[inline(always)] + pub(crate) fn find( + &self, + haystack: &[u8], + needle: &[u8], + ) -> Option<usize> { + // SAFETY: sse2 is enabled on all x86_64 targets, so this is always + // safe to call. + unsafe { self.find_impl(haystack, needle) } + } + + /// The implementation of find marked with the appropriate target feature. + /// + /// # Safety + /// + /// This is safe to call in all cases since sse2 is guaranteed to be part + /// of x86_64. It is marked as unsafe because of the target feature + /// attribute. + #[target_feature(enable = "sse2")] + unsafe fn find_impl( + &self, + haystack: &[u8], + needle: &[u8], + ) -> Option<usize> { + genericsimd::fwd_find::<__m128i>(&self.0, haystack, needle) + } +} + +#[cfg(all(test, feature = "std", not(miri)))] +mod tests { + use crate::memmem::{prefilter::PrefilterState, NeedleInfo}; + + fn find( + _: &mut PrefilterState, + ninfo: &NeedleInfo, + haystack: &[u8], + needle: &[u8], + ) -> Option<usize> { + super::Forward::new(ninfo, needle).unwrap().find(haystack, needle) + } + + #[test] + fn prefilter_permutations() { + use crate::memmem::prefilter::tests::PrefilterTest; + + // SAFETY: sse2 is enabled on all x86_64 targets, so this is always + // safe to call. + unsafe { + PrefilterTest::run_all_tests_filter(find, |t| { + // This substring searcher only works on certain configs, so + // filter our tests such that Forward::new will be guaranteed + // to succeed. (And also remove tests with a haystack that is + // too small.) + let fwd = match super::Forward::new(&t.ninfo, &t.needle) { + None => return false, + Some(fwd) => fwd, + }; + t.haystack.len() >= fwd.min_haystack_len() + }) + } + } +} |