On Fri, Apr 17, 2015 at 01:54:27PM -0700, Junio C Hamano wrote: > > Since the strings we are matching are literals, we could also record > > their sizes in the object_type_strings array and check the length first > > before even calling strncmp. I doubt this is a performance hot-spot, > > though. > > > > You could also potentially just use strlen(object_type_strings[i]), but > > I'm not sure if compilers will optimize out the strlen in this case, > > since it is in a loop. > > That thought crossed my mind while reading your patch. It could > even make it go faster if we made object_type_strings into an array > of counted strings (i.e. "struct { const char *str; int len; }") > and then took advantage of the fact that we have lengths of both. Right, that was what I meant. I'd be surprised if it appreciably speeds things up, but I guess it is not too complicated to do. > +static struct { > + const char *str; > + int len; > +} object_type_name[] = { > + { NULL, 0 }, /* OBJ_NONE = 0 */ > + { "commit", 6 }, /* OBJ_COMMIT = 1 */ > + { "tree", 4 }, /* OBJ_TREE = 2 */ > + { "blob", 4 }, /* OBJ_BLOB = 3 */ > + { "tag", 3 }, /* OBJ_TAG = 4 */ > }; I had envisioned a macro like: #define SIZED_STRING(x) { (x), (sizeof(x) - 1) } though perhaps that is overkill for such a short list (that we don't even expect to change). -Peff -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html