Tweaked the hash table resizer, it now is more careful about increasing the

size of the table when it can reclaim empty space from deletes, and it allows
the table to shrink if little enough space is being used.

1 files changed, 14 insertions, 2 deletions

diff --git a/src/hash.h b/src/hash.h
index 26b16c7..5c7bc78 100644
--- a/src/hash.h
+++ b/src/hash.h
@@ -42,10 +42,22 @@ namespace Bu
          */
         struct __calcNextTSize_fast
         {
-                uint32_t operator()( uint32_t nCapacity, uint32_t, uint32_t nDeleted ) const
+                uint32_t operator()( uint32_t nCapacity, uint32_t nFilled,
+                                uint32_t nDeleted ) const
                 {
-                        if( nDeleted >= nCapacity/2 )
+                        // This frist case will allow hashtables that are mostly deleted
+                        // items to reset to small allocations
+                        if( nFilled-nDeleted <= nCapacity/4 )
+                        {
+                                nCapacity = 11;
+                                while( nCapacity < nFilled*5/4 )
+                                        nCapacity = nCapacity*2+1;
+                                return nCapacity;
+                        }
+                        // This will hopefully prevent hash tables from growing needlessly
+                        if( nFilled-nDeleted <= nCapacity/2 )
                                 return nCapacity;
+                        // Otherwise, just increase the capacity
                         return nCapacity*2+1;
                 }
         };