Commit Graph

4 Commits

Author SHA1 Message Date
Nicolas Pitre
fb73ac392c lib/os/cbprintf_nano.c: several improvements
This makes cbprintf_nano.c much closer to the standard printf and
therefore more useful. The following are now implemented:

- right justification for everything (only for numbers previously)
- precision value for numbers, chars and strings
- width/precision passed as arguments with *
- "unlimited" padding length
- lower/uppercase hex output
- the #, + and ' ' flags are supported

And the code was heavily reworked to reduce its size as much as
possible to mitigate the size growth. Still, the binary resulting
from cbprintf_nano.c is now between 10% and 20% bigger depending on
the architecture. This is still far smaller than cbprintf_complete.c
which remains about twice as big on average even without FP support.

Many unit tests that were skipped with CONFIG_CBPRINTF_NANO are now
enabled, and a few more were added for good measure.

Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
2021-02-23 19:39:59 +01:00
Peter Bigot
d12a99588b lib: cbprintf: remove cbprintf_arglen
This function was designed to support the logging infrastructure's
need to copy values from va_list structures.  It did not meet that
need, since some values need to be changed based on additional data
that is only available when the complete format specification is
examined.  Remove the function as unnecessary.

Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
2021-01-07 14:02:06 +01:00
Nicolas Pitre
d583af7707 lib/os/cbprintf_nano.c: simplifications and enhancements
Simplify the code to increase readability, and fix right-padding
for %p.

Also, the compiled code is smaller with those changes applied.

Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
2020-11-17 11:34:25 +01:00
Peter Bigot
33103828dc lib: add cbprintf capability
This commit adds a C99 stdio value formatter capability where
generated text is emitted through a callback.  This allows generation
of arbitrarily long output without a buffer, functionality that is
core to printk, logging, and other system and application needs.

The formatter supports most C99 specifications, excluding:
* %Lf long double conversion
* wide character output

Kconfig options allow disabling features like floating-point
conversion if they are not necessary.  By default most conversions are
enabled.

The original z_vprintk() implementation is adapted to meet the
interface requirements of cbvprintf, and made available as an opt-in
feature for space-constrained applications that do not need full
formatting support.

Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
2020-11-13 06:38:01 -05:00