On Sat, Jul 5, 2008 at 3:24 PM, Jan Engelhardt <jengelh@xxxxxxxxxx> wrote: > > On Saturday 2008-07-05 14:52, Vegard Nossum wrote: >>> On Saturday 2008-07-05 00:01, Andrew Morton wrote: >>>> >>>>We don't know how much interest there would be in churning NIPQUAD from >>>>the net guys. Interestingly, there's also %C (wint_t) which is a >>>>32-bit quantity. So we could just go and say "%C prints an ipv4 >>>>address" and be done with it. But there's no way of doing that for >>>>ipv6 addresses so things would become asymmetrical there. >>> >>> struct in6_addr src; >>> printk("Source address: %p{ipv6}\n", &src); >>> >>> How about %p{feature}? >> >>Something like this? >> >>+static char *custom_format(char *buf, char *end, >>+ const char *fmt, unsigned int fmtlen, void *arg) > > I'd use const void *arg here, so nobody gets the idea > that you could modify the argument while printing :) > Oops, of course. Thanks. >>+{ >>+ if (!strncmp(fmt, "sym", fmtlen)) { ... >>+ } > > And I assume it's then as simple as > > } else if (strncmp(fmt, "nip6", fmtlen) == 0) { > snprintf(buf, end - buf (+1?), NIP6_FMT in expanded form, > NIP6 in expanded form(arg)); > } > > Hm, that's going to get a big function when everyone adds their > fmttypes. > Yes. Luckily, the entry point is then fixed in a single place and it's easy to convert it into something more dynamic :-) A static array wouldn't help much because it still concentrates all the names. But we could at least do a binary search on that and get some speed improvements if it grows large. I think the most elegant solution would be a macro similar to the initcall macros, that adds the custom extensions to a table which is defined by a special linker section. This allows complete decentralization, but I don't think it's possible to do binary search on the names anymore. Dynamic registering/unregistering could be done too. Maybe this is a good thing for modules... Thoughts? >>+ >>+ return buf; >>+} >>+ >> static char *number(char *buf, char *end, unsigned long long num, int base, int size, int precision, int type) >> { >> /* we are called with base 8, 10 or 16, only, thus don't need "G..." */ >>@@ -648,6 +673,25 @@ int vsnprintf(char *buf, size_t size, const char *fmt, va_list args) >> continue; >> >> case 'p': >>+ if (fmt[1] == '{') { >>+ const char *cfmt; >>+ >>+ /* Skip the '%{' */ >>+ ++fmt; >>+ ++fmt; >>+ > > Not this? > > /* Skip the '%p{' */ > fmt += 3; > Oops, the comment is wrong. It should say: "Skip the p{". But fmt += 3 is wrong. Since fmt[0] is at this point 'p', and fmt[1] is '{'. The % and flags, etc. have already been skipped by the common code. So it should be fmt += 2 :-) Thanks! Vegard -- "The animistic metaphor of the bug that maliciously sneaked in while the programmer was not looking is intellectually dishonest as it disguises that the error is the programmer's own creation." -- E. W. Dijkstra, EWD1036 -- To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
![]() |