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SubjectRe: [PATCH] Add parse_integer() (replacement for simple_strto*())
On Thu, 9 Apr 2015 18:26:14 +0300 Alexey Dobriyan <adobriyan@gmail.com> wrote:

> kstrto*() and kstrto*_from_user() family of functions were added
> help with parsing one integer written as string to proc/sysfs/debugfs
> files and pass it elsewhere. But they have a limitation: string passed
> must end with \0 or \n\0. There are enough places where kstrto*()
> functions can't be used because of this limitation. Trivial example:
> parse "%u.%u".
>
> ...
>
> include/linux/kernel.h | 72 +++++++++++++++++++
> lib/Makefile | 1
> lib/kstrtox.c | 27 +------
> lib/parse-integer.c | 180 +++++++++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 257 insertions(+), 23 deletions(-)

That's a lot of code for something which is almost the same as
kstrtofoo().

Can we hack up _kstrtoull() to optionally provide the new behaviour?
We could use the top bit of `base' to select the behaviour. Something
like

--- a/lib/kstrtox.c~a
+++ a/lib/kstrtox.c
@@ -87,19 +87,23 @@ static int _kstrtoull(const char *s, uns
{
unsigned long long _res;
unsigned int rv;
+ const char *cursor;
+ const unsigned int __base = base & 0x7fffffff;

- s = _parse_integer_fixup_radix(s, &base);
- rv = _parse_integer(s, base, &_res);
+ cursor = _parse_integer_fixup_radix(s, &__base);
+ rv = _parse_integer(cursor, __base, &_res);
if (rv & KSTRTOX_OVERFLOW)
return -ERANGE;
if (rv == 0)
return -EINVAL;
- s += rv;
- if (*s == '\n')
- s++;
- if (*s)
- return -EINVAL;
+ cursor += rv;
*res = _res;
+ if (base & 0x80000000)
+ return cursor - s;
+ if (*cursor == '\n')
+ cursor++;
+ if (*cursor)
+ return -EINVAL;
return 0;
}

then add a bunch of wrappers?

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