Move probing logic into control module

src/control/group/generic.rs

@@ -50,20 +50,23 @@ impl Group {
     /// Number of bytes in the group.
     pub(crate) const WIDTH: usize = mem::size_of::<Self>();
 
+    /// Double the group width; size of [`Group::static_empty`].
+    pub(crate) const DOUBLE_WIDTH: usize = Group::WIDTH * 2;
+
     /// Returns a full group of empty tags, suitable for use as the initial
     /// value for an empty hash table.
     ///
     /// This is guaranteed to be aligned to the group size.
     #[inline]
-    pub(crate) const fn static_empty() -> &'static [Tag; Group::WIDTH] {
+    pub(crate) const fn static_empty() -> &'static [Tag; Group::DOUBLE_WIDTH] {
         #[repr(C)]
         struct AlignedTags {
             _align: [Group; 0],
-            tags: [Tag; Group::WIDTH],
+            tags: [Tag; Group::DOUBLE_WIDTH],
         }
         const ALIGNED_TAGS: AlignedTags = AlignedTags {
             _align: [],
-            tags: [Tag::EMPTY; Group::WIDTH],
+            tags: [Tag::EMPTY; Group::DOUBLE_WIDTH],
         };
         &ALIGNED_TAGS.tags
     }

src/control/group/neon.rs

@@ -21,20 +21,23 @@ impl Group {
     /// Number of bytes in the group.
     pub(crate) const WIDTH: usize = mem::size_of::<Self>();
 
+    /// Double the group width; size of [`Group::static_empty`].
+    pub(crate) const DOUBLE_WIDTH: usize = Group::WIDTH * 2;
+
     /// Returns a full group of empty tags, suitable for use as the initial
     /// value for an empty hash table.
     ///
     /// This is guaranteed to be aligned to the group size.
     #[inline]
-    pub(crate) const fn static_empty() -> &'static [Tag; Group::WIDTH] {
+    pub(crate) const fn static_empty() -> &'static [Tag; Group::DOUBLE_WIDTH] {
         #[repr(C)]
         struct AlignedTags {
             _align: [Group; 0],
-            tags: [Tag; Group::WIDTH],
+            tags: [Tag; Group::DOUBLE_WIDTH],
         }
         const ALIGNED_TAGS: AlignedTags = AlignedTags {
             _align: [],
-            tags: [Tag::EMPTY; Group::WIDTH],
+            tags: [Tag::EMPTY; Group::DOUBLE_WIDTH],
         };
         &ALIGNED_TAGS.tags
     }

src/control/group/sse2.rs

@@ -26,21 +26,24 @@ impl Group {
     /// Number of bytes in the group.
     pub(crate) const WIDTH: usize = mem::size_of::<Self>();
 
+    /// Double the group width; size of [`Group::static_empty`].
+    pub(crate) const DOUBLE_WIDTH: usize = Group::WIDTH * 2;
+
     /// Returns a full group of empty tags, suitable for use as the initial
     /// value for an empty hash table.
     ///
     /// This is guaranteed to be aligned to the group size.
     #[inline]
     #[allow(clippy::items_after_statements)]
-    pub(crate) const fn static_empty() -> &'static [Tag; Group::WIDTH] {
+    pub(crate) const fn static_empty() -> &'static [Tag; Group::DOUBLE_WIDTH] {
         #[repr(C)]
         struct AlignedTags {
             _align: [Group; 0],
-            tags: [Tag; Group::WIDTH],
+            tags: [Tag; Group::DOUBLE_WIDTH],
         }
         const ALIGNED_TAGS: AlignedTags = AlignedTags {
             _align: [],
-            tags: [Tag::EMPTY; Group::WIDTH],
+            tags: [Tag::EMPTY; Group::DOUBLE_WIDTH],
         };
         &ALIGNED_TAGS.tags
     }

src/control/mod.rs

@@ -1,10 +1,12 @@
 mod bitmask;
 mod group;
+mod probe;
 mod tag;
 
 use self::bitmask::BitMask;
 pub(crate) use self::{
     bitmask::BitMaskIter,
     group::Group,
+    probe::{Probe, ProbeItems},
     tag::{Tag, TagSliceExt},
 };