Hi!, On Thu, 2008-02-14 at 17:31 +0100, Laurent Aguerreche wrote: > Le mercredi 13 février 2008 à 18:09 +0100, Carlos Garnacho a écrit : > > Hi!, > > > > This was just a heads up to these three bugs: > > > > #513692 : This one just packs booleans in guints, so it should improve > > size in most used structs. > > Is it so interesting to save some bytes this way? > > In tracker-utils, this patch will replace 25 gbooleans with 25 "uint:1". > If I assume that gboolean is a typedef of gint and that gint uses 4 > bytes, this patch will save (25*4)-25 = 75 bytes (perhaps a little bit > more but IMHO not much more because we use pointers everywhere and we > take care of memory allocations). > So we would prefer to write some weird things (using of unsigned int > instead of booleans) to save ~75 bytes?
There are several copies of such structures during all the application lifetime, so if you save for example 16 bytes (5 gboolean = 20 bytes, 1 guint = 4 bytes) in one structure, having say 100 of these structures around saves you already 1600 bytes. To me it's a no brainer trying to get used to do such effortless improvements as you code. > > Another question: why glib does use a typedef of gint instead of a > typedef of "guint:1" for its booleans? This is only applicable to structs and unions, and the define would have to get like: #define gboolean(var) guint (var) : 1 quite weird for a data type. > > > #513691 : a similar improvement to #511788 (already committed) in a > > different function. > > + res = g_ptr_array_sized_new (100); > > What is "100"?! Perhaps should have done a #define for that :), it's just a good enough default value, so the array has a sensible initial size, and it doesn't need too frequent reallocations when the array grows at first. Regards, Carlos _______________________________________________ tracker-list mailing list [email protected] http://mail.gnome.org/mailman/listinfo/tracker-list
