libs/libc/time: Add configuration options for the strftime#19024
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acassis
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Keep the memory optimizations coming!
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Rebase on latest master |
michallenc
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xiaoxiang781216
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Hi: Could you Rebase your PR with the Master Branch? We fixed the Segger SystemView Error in the CI Build. Thanks :-) |
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This adds 3 configuration options for the lib_strftime, which can be used to save flash memory when all the formatters are not needed by an embedded application. There is always a minimal set of formatters supported: "%a, %b/%h, %d, %H, %m, %M, %S, %Y, %%". To add on top of that one can specify: - LIBC_STRFTIME_C_STANDARD_FORMATS : All ISO-C conversion specifiers - LIBC_STRFTIME_POSIX_FORMATS : Additional posix formats - LIBC_STRFTIME_NONSTANDARD_FORMATS : Additional GNU nonstandard formats All of these are enabled by default unless building for CONFIG_DEFAULT_SMALL. Disabling these options can save over 3KB of flash on an 32-bit ARM system, when all the format specifiers are not needed. Signed-off-by: Jukka Laitinen <jukka.laitinen@tii.ae>
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re-based to pass the CI |
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FYI: I restarted the CI Build to fix the Docker Image |
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Summary
This adds 3 configuration options for the lib_strftime, which can be used to save flash memory when all the formatters are not needed by an embedded application.
There is always a minimal set of formatters supported: "%a, %b/%h, %d, %H, %m, %M, %S, %Y, %%". To add on top of that one can specify:
All of these are enabled by default unless building for CONFIG_DEFAULT_SMALL. Disabling these options can save over 3KB of flash on an 32-bit ARM system, when all the format specifiers are not needed.
I have grouped the switch-cases according to the flags, thinking that it was nicer. Now looking at this, I realize that it is quite difficult to review. I can also keep the switch-cases in order, and just scatter the ifdefs around, if that would be preferable, just let me know!
Impact
No impact, unless building for CONFIG_BUILD_SMALL (in which case the formatters needs to be enabled specifically), or if formatters are specifically disabled in the configuration.
Testing
Compilation has been tested on nucleo-f767zi:nsh:
boards/arm/stm32f7/nucleo-f767zi/configs/nsh/defconfig:
CONFIG_STM32F7_BKPSRAM=y
CONFIG_STM32F7_BBSRAM=y
CONFIG_STM32F7_PWR=y
CONFIG_STM32F7_SAVE_CRASHDUMP=y
boards/arm/stm32f7/nucleo-f767zi/configs/nsh/defconfig:
Diff: 3284 bytes smaller image
In addition, functionality is checked with "date" on Pixhawk4 board, using only minimal set of formatters: