[PATCH v1 1/1] lib/vsprintf.c: Amend static asserts for format specifier flags

[PATCH v1 1/1] lib/vsprintf.c: Amend static asserts for format specifier flags

[Andy Shevchenko]

There are couple of improvements to static asserts against
the format specifier flags:

- new static assert for SIGN
- fix static assert for SMALL

SMALL is not equal to ASCII code of white space, it equals to
the bit difference between capital and small letters (however
the value is the same, semantically expression means different
things).

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 lib/vsprintf.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index f15a49ff6fab..ddfb3d836f38 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -407,8 +407,9 @@ int num_to_str(char *buf, int size, unsigned long long num, unsigned int width)
 #define SMALL	32		/* use lowercase in hex (must be 32 == 0x20) */
 #define SPECIAL	64		/* prefix hex with "0x", octal with "0" */
 
+static_assert(SIGN == 1);
 static_assert(ZEROPAD == ('0' - ' '));
-static_assert(SMALL == ' ');
+static_assert(SMALL == ('a' ^ 'A'));
 
 enum format_type {
 	FORMAT_TYPE_NONE, /* Just a string part */
-- 
2.33.0

Re: [PATCH v1 1/1] lib/vsprintf.c: Amend static asserts for format specifier flags

[Petr Mladek]

On Tue 2021-10-26 17:03:56, Andy Shevchenko wrote:
> There are couple of improvements to static asserts against
> the format specifier flags:
> 
> - new static assert for SIGN
> - fix static assert for SMALL
> 
> SMALL is not equal to ASCII code of white space, it equals to
> the bit difference between capital and small letters (however
> the value is the same, semantically expression means different
> things).
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

The patch has been committed into printk/linux.git, branch for-5.16.

Best Regards,
Petr