Merge remote-tracking branch 'upstream/master' into aucmd_textputpostaucmd_textputpost

1 files changed, 59 insertions, 0 deletions

diff --git a/src/nvim/hashtab_defs.h b/src/nvim/hashtab_defs.h
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+++ b/src/nvim/hashtab_defs.h
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+#pragma once
+
+#include <stddef.h>
+
+/// Type for hash number (hash calculation result).
+typedef size_t hash_T;
+
+/// Hashtable item.
+///
+/// Each item has a NUL terminated string key.
+/// A key can appear only once in the table.
+///
+/// A hash number is computed from the key for quick lookup.  When the hashes
+/// of two different keys point to the same entry an algorithm is used to
+/// iterate over other entries in the table until the right one is found.
+/// To make the iteration work removed keys are different from entries where a
+/// key was never present.
+///
+/// Note that this does not contain a pointer to the key and another pointer to
+/// the value. Instead, it is assumed that the key is contained within the
+/// value, so that you can get a pointer to the value subtracting an offset from
+/// the pointer to the key.
+/// This reduces the size of this item by 1/3.
+typedef struct hashitem_S {
+  /// Cached hash number for hi_key.
+  hash_T hi_hash;
+
+  /// Item key.
+  ///
+  /// Possible values mean the following:
+  /// NULL                      : Item was never used.
+  /// HI_KEY_REMOVED            : Item was removed.
+  /// (Any other pointer value) : Item is currently being used.
+  char *hi_key;
+} hashitem_T;
+
+/// Initial size for a hashtable.
+/// Our items are relatively small and growing is expensive, thus start with 16.
+/// Must be a power of 2.
+/// This allows for storing 10 items (2/3 of 16) before a resize is needed.
+enum { HT_INIT_SIZE = 16, };
+
+/// An array-based hashtable.
+///
+/// Keys are NUL terminated strings. They cannot be repeated within a table.
+/// Values are of any type.
+///
+/// The hashtable grows to accommodate more entries when needed.
+typedef struct hashtable_S {
+  hash_T ht_mask;        ///< mask used for hash value
+                         ///< (nr of items in array is "ht_mask" + 1)
+  size_t ht_used;        ///< number of items used
+  size_t ht_filled;      ///< number of items used or removed
+  int ht_changed;        ///< incremented when adding or removing an item
+  int ht_locked;         ///< counter for hash_lock()
+  hashitem_T *ht_array;  ///< points to the array, allocated when it's
+                         ///< not "ht_smallarray"
+  hashitem_T ht_smallarray[HT_INIT_SIZE];  ///< initial array
+} hashtab_T;