hashmap: size hashmap bucket array dynamically

Instead of fixing the hashmap bucket array to 127 entries dynamically
size it, starting with a smaller one of 31. As soon as a fill level of
75% is reached, quadruple the size, and so on.

This should siginficantly optimize the lookup time in large tables
(from O(n) back to O(1)), and save memory on smaller tables (which most
are).

1 files changed, 1 insertions, 0 deletions

diff --git a/src/shared/hashmap.h b/src/shared/hashmap.h
index 15b7e27585..3d4f6721bc 100644
--- a/src/shared/hashmap.h
+++ b/src/shared/hashmap.h
@@ -76,6 +76,7 @@ int hashmap_move_one(Hashmap *h, Hashmap *other, const void *key);
 
 unsigned hashmap_size(Hashmap *h) _pure_;
 bool hashmap_isempty(Hashmap *h) _pure_;
+unsigned hashmap_buckets(Hashmap *h) _pure_;
 
 void *hashmap_iterate(Hashmap *h, Iterator *i, const void **key);
 void *hashmap_iterate_backwards(Hashmap *h, Iterator *i, const void **key);