| 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() |
| }) |
| } |
| } |
| } |