1 files changed, 159 insertions, 0 deletions
diff --git a/src/nvim/map_key_impl.c.h b/src/nvim/map_key_impl.c.h
new file mode 100644
index 0000000000..5568c049ab
--- /dev/null
+++ b/src/nvim/map_key_impl.c.h
@@ -0,0 +1,159 @@
+#include "nvim/map_defs.h"
+#include "nvim/memory.h"
+
+#ifndef KEY_NAME
+// Don't error out. it is nice to type-check the file in isolation, in clangd or otherwise
+# define KEY_NAME(x) x##int
+# define hash_int(x) ((uint32_t)x)
+# define equal_int(x, y) ((x) == (y))
+#endif
+
+#define SET_TYPE KEY_NAME(Set_)
+#define KEY_TYPE KEY_NAME()
+
+/// find bucket to get or put "key"
+///
+/// set->h.hash assumed already allocated!
+///
+/// @return bucket index, or MH_TOMBSTONE if not found and `put` was false
+///         mh_is_either(hash[rv]) : not found, but this is the place to put
+///         otherwise: hash[rv]-1 is index into key/value arrays
+uint32_t KEY_NAME(mh_find_bucket_)(SET_TYPE *set, KEY_TYPE key, bool put)
+{
+  MapHash *h = &set->h;
+  uint32_t step = 0;
+  uint32_t mask = h->n_buckets - 1;
+  uint32_t k = KEY_NAME(hash_)(key);
+  uint32_t i = k & mask;
+  uint32_t last = i;
+  uint32_t site = put ? last : MH_TOMBSTONE;
+  while (!mh_is_empty(h, i)) {
+    if (mh_is_del(h, i)) {
+      if (site == last) {
+        site = i;
+      }
+    } else if (KEY_NAME(equal_)(set->keys[h->hash[i] - 1], key)) {
+      return i;
+    }
+    i = (i + (++step)) & mask;
+    if (i == last) {
+      abort();
+    }
+  }
+  if (site == last) {
+    site = i;
+  }
+  return site;
+}
+
+/// @return index into set->keys if found, MH_TOMBSTONE otherwise
+uint32_t KEY_NAME(mh_get_)(SET_TYPE *set, KEY_TYPE key)
+{
+  if (set->h.n_buckets == 0) {
+    return MH_TOMBSTONE;
+  }
+  uint32_t idx = KEY_NAME(mh_find_bucket_)(set, key, false);
+  return (idx != MH_TOMBSTONE) ? set->h.hash[idx] - 1 : MH_TOMBSTONE;
+}
+
+/// Rebuild hash from keys[] array
+///
+/// set->h.hash must be allocated and empty before&alling!
+void KEY_NAME(mh_rehash_)(SET_TYPE *set)
+{
+  for (uint32_t k = 0; k < set->h.n_keys; k++) {
+    uint32_t idx = KEY_NAME(mh_find_bucket_)(set, set->keys[k], true);
+    // there must be tombstones when we do a rehash
+    if (!mh_is_empty((&set->h), idx)) {
+      abort();
+    }
+    set->h.hash[idx] = k + 1;
+  }
+  set->h.n_occupied = set->h.size = set->h.n_keys;
+}
+
+/// Put a key. Return the existing item if found
+///
+/// Allocates/resizes the hash table and/or keys[] table if needed.
+///
+/// @param[out] new mandatory. Reveals if an existing key was found. In addition,
+///                 if new item, indicates if keys[] was resized.
+///
+/// @return keys index
+uint32_t KEY_NAME(mh_put_)(SET_TYPE *set, KEY_TYPE key, MHPutStatus *new)
+{
+  MapHash *h = &set->h;
+  // Might rehash ahead of time if "key" already existed. But it was
+  // going to happen soon anyway.
+  if (h->n_occupied >= h->upper_bound) {
+    // If we likely were to resize soon, do it now to avoid extra rehash
+    // TODO(bfredl): we never shrink. but maybe that's fine
+    if (h->size >= h->upper_bound * 0.9) {
+      mh_realloc(h, h->n_buckets + 1);
+    } else {
+      // Just a lot of tombstones from deleted items, start all over again
+      memset(h->hash, 0, h->n_buckets * sizeof(*h->hash));
+      h->size = h->n_occupied = 0;
+    }
+    KEY_NAME(mh_rehash_)(set);
+  }
+
+  uint32_t idx = KEY_NAME(mh_find_bucket_)(set, key, true);
+
+  if (mh_is_either(h, idx)) {
+    h->size++;
+    if (mh_is_empty(h, idx)) {
+      h->n_occupied++;
+    }
+
+    uint32_t pos = h->n_keys++;
+    if (pos >= h->keys_capacity) {
+      h->keys_capacity = MAX(h->keys_capacity * 2, 8);
+      set->keys = xrealloc(set->keys, h->keys_capacity * sizeof(KEY_TYPE));
+      *new = kMHNewKeyRealloc;
+    } else {
+      *new = kMHNewKeyDidFit;
+    }
+    set->keys[pos] = key;
+    h->hash[idx] = pos + 1;
+    return pos;
+  } else {
+    *new = kMHExisting;
+    uint32_t pos = h->hash[idx] - 1;
+    if (!KEY_NAME(equal_)(set->keys[pos], key)) {
+      abort();
+    }
+    return pos;
+  }
+}
+
+/// Deletes `*key` if found, do nothing otherwise
+///
+/// @param[in, out] key modified to the value contained in the set
+/// @return the index the item used to have in keys[]
+///         MH_TOMBSTONE if key was not found
+uint32_t KEY_NAME(mh_delete_)(SET_TYPE *set, KEY_TYPE *key)
+{
+  if (set->h.size == 0) {
+    return MH_TOMBSTONE;
+  }
+  uint32_t idx = KEY_NAME(mh_find_bucket_)(set, *key, false);
+  if (idx != MH_TOMBSTONE) {
+    uint32_t k = set->h.hash[idx] - 1;
+    set->h.hash[idx] = MH_TOMBSTONE;
+
+    uint32_t last = --set->h.n_keys;
+    *key = set->keys[k];
+    set->h.size--;
+    if (last != k) {
+      uint32_t idx2 = KEY_NAME(mh_find_bucket_)(set, set->keys[last], false);
+      if (set->h.hash[idx2] != last + 1) {
+        abort();
+      }
+      set->h.hash[idx2] = k + 1;
+      set->keys[k] = set->keys[last];
+    }
+    return k;
+  }
+  return MH_TOMBSTONE;
+}