From: Philip Oakley <philipoakley@iee.org>
Date: Fri, 08 Nov 2013 14:13:30 GMT
Subject: Re: [PATCH v4 02/14] add a hashtable implementation that supports O(1) removal
Message-ID: <2BEA8A50DFB9411BA89CAB9236687F5B@PhilipOakley>
In-Reply-To: <527CBC8E.6050507@gmail.com>

From: "Karsten Blees" <karsten.blees@gmail.com>

> However, defining the constants inversely is a bit unintuitive (i.e. 
> 1.25 instead of 0.8, 6 instead of 0.166). Perhaps the thresholds 
> should also be calculated once on resize, not on every add / remove.
>
> What about this:
>
> #define HASHMAP_GROW_AT 80
> #define HASHMAP_SHRINK_AT 16

mico-bikeshed adding a code comment...

 #define HASHMAP_GROW_AT 80    /* percent */
 #define HASHMAP_SHRINK_AT 16    /* percent */

>
> ...in rehash:
>
> map->grow_at = (unsigned int)((uint64_t) map->tablesize * 
> HASHMAP_GROW_AT / 100);
> map->shrink_at = (unsigned int)((uint64_t) map->tablesize * 
> HASHMAP_SHRINK_AT / 100);
>

[No need to add to cc...]

regards

Philip