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 <andriy.shevchenko@xxxxxxxxxxxxxxx>
> ---
> 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
