From mboxrd@z Thu Jan 1 00:00:00 1970 From: Petr Mladek Subject: Re: [PATCH v1 1/4] lib/vsprintf: Allow to override date and time separator Date: Tue, 11 May 2021 16:14:56 +0200 Message-ID: References: <20210510150413.59356-1-andriy.shevchenko@linux.intel.com> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1620742497; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=K/INbdoVMnVmSuC17hTHtZF9dvmPCdhexs0UvUqBKdU=; b=ZZwWnWCNMaCOX6VuJYsh6oDMSznOuCqE3OHNdSQVV9/C2i0EXmlVIOuh76zDI23pRGvYVq EdiYKyL07Upk0ornxhN4Gi2nyy4RC7SRHE8PQ9BMhtJqB0xiBEOX6bKgzrgn7jH38dTUrN WPMatuYcPOyjzG1cFGyFyLMWper17QY= Content-Disposition: inline In-Reply-To: <20210510150413.59356-1-andriy.shevchenko-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Andy Shevchenko Cc: JC Kuo , Joe Perches , Sumit Garg , linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-nilfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kgdb-bugreport-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Steven Rostedt , Sergey Senozhatsky , Rasmus Villemoes , Jonathan Corbet , Mathias Nyman , Greg Kroah-Hartman , Thierry Reding , Jonathan Hunter , Ryusuke Konishi , Jason Wessel , Daniel Thompson , Douglas Anderson On Mon 2021-05-10 18:04:10, Andy Shevchenko wrote: > ISO 8601 defines 'T' as a separator between date and time. Though, > some ABIs use time and date with ' ' separator instead. > > Add a flavour to the %pt specifier to override default separator. > > Signed-off-by: Andy Shevchenko > --- > Documentation/core-api/printk-formats.rst | 6 +++++- > lib/test_printf.c | 5 +++++ > lib/vsprintf.c | 19 ++++++++++++++++--- > 3 files changed, 26 insertions(+), 4 deletions(-) > > diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst > index f063a384c7c8..bc85fd4685e7 100644 > --- a/Documentation/core-api/printk-formats.rst > +++ b/Documentation/core-api/printk-formats.rst > @@ -514,9 +514,10 @@ Time and date > :: > > %pt[RT] YYYY-mm-ddTHH:MM:SS > + %pt[RT]s YYYY-mm-dd HH:MM:SS > %pt[RT]d YYYY-mm-dd > %pt[RT]t HH:MM:SS > - %pt[RT][dt][r] > + %pt[RT][dt][rs] Sigh, we do not have clear rules what [xy] means. It might be: + always use one of them + optionally use one of them + always use any of them + optionally use any of them %pt[RT][dt][rs] is a great mix: + R or T is required, the rest is optional + 'd' or 't' can be used but both together are not supported + any variant of 'r' and 's' is supported including various ordering Honestly, I do not know about any magic solution that might make it easier to understand these monster modifiers. Well, what about using the following at least in this case: %pt[RT][dt][r][s] It might help to understand that both 'r' and 's' can be used at the same time. An attempt to distinguishing all the possibilities might be: %pt{RT}[{dt}][r][s] where [] means that it is optional and {} means one of them must be chosen. But I am not sure if it really makes the life easier. Anyway, this would be for another patch that updates the entire printk-formats.rst. > > For printing date and time as represented by:: > > @@ -528,6 +529,9 @@ in human readable format. > By default year will be incremented by 1900 and month by 1. > Use %pt[RT]r (raw) to suppress this behaviour. > > +The %pt[RT]s (space) will override ISO 8601 by using ' ' instead of 'T' > +between date and time. It won't have any effect when date or time is omitted. > + > Passed by reference. > > struct clk > diff --git a/lib/vsprintf.c b/lib/vsprintf.c > index f0c35d9b65bf..5f36c7a43cdc 100644 > --- a/lib/vsprintf.c > +++ b/lib/vsprintf.c > @@ -1834,7 +1834,8 @@ char *rtc_str(char *buf, char *end, const struct rtc_time *tm, > struct printf_spec spec, const char *fmt) > { > bool have_t = true, have_d = true; > - bool raw = false; > + bool raw = false, space = false; > + bool found = true; > int count = 2; > > if (check_pointer(&buf, end, tm, spec)) > @@ -1851,14 +1852,26 @@ char *rtc_str(char *buf, char *end, const struct rtc_time *tm, > break; > } > > - raw = fmt[count] == 'r'; > + do { > + switch (fmt[count++]) { > + case 'r': > + raw = true; > + break; > + case 's': > + space = true; > + break; > + default: > + found = false; > + break; > + } > + } while (found); > > if (have_d) > buf = date_str(buf, end, tm, raw); > if (have_d && have_t) { > /* Respect ISO 8601 */ The comment is slightly misleding now. What about something like? /* 'T' by ISO 8601. */ Or maybe call the variable: iso_8601, remove the comment, and invert the logic: bool iso_8601 = true; case 's': iso_8601 = false; break; *buf = iso_8601 ? 'T' : ' '; > if (buf < end) > - *buf = 'T'; > + *buf = space ? ' ' : 'T'; > buf++; > } > if (have_t) Best Regards, Petr