Messages in this thread | | | Date | Fri, 14 Mar 2008 10:11:57 -0700 | From | Randy Dunlap <> | Subject | Re: [PATCH 01/10] Add macros similar to min/max/min_t/max_t. |
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Harvey Harrison wrote: > On Fri, 2008-03-14 at 09:49 -0700, Randy Dunlap wrote: >> Harvey Harrison wrote: >>> On Fri, 2008-03-14 at 09:34 -0700, Randy Dunlap wrote: >>>> On Thu, 13 Mar 2008 22:18:45 -0700 Harvey Harrison wrote: >>>> Where is some blurb/comment about what "clamp" means/does? >>>> min/max are well understood, but clamp? Is that a shop tool? >>>> I think I have a few out in my garage. >>> Sure, I'll do that..does kernel-doc actually work for macros? >> Yes, it does. >> > > OK, here's what I've come up with: > > /** > * clamp - return a value clamped to a given range with strict typechecking > * @val: current value > * @min: minimum allowable value > * @max: maximum allowable value > * > * This macro does strict typechecking of min/max to make sure they of the
they are of
> * same type as val. See the unnecessary pointer comparisons. > */ > #define clamp(val, min, max) ({ \ > typeof(val) __val = (val); \ > typeof(min) __min = (min); \ > typeof(max) __max = (max); \ > (void) (&__val == &__min); \ > (void) (&__val == &__max); \ > __val = __val < __min ? __min: __val; \ > __val > __max ? __max: __val; }) > > /** > * clamp_t - return a value clamped to a given range using a given type > * @type: the type of variable to use > * @val: current value > * @min: minimum allowable value > * @max: maximum allowable value > * > * This macro does no typechecking and uses temporary variables of type > * 'type' to make all the comparisons. > */ > #define clamp_t(type, val, min, max) ({ \ > type __val = (val); \ > type __min = (min); \ > type __max = (max); \ > __val = __val < __min ? __min: __val; \ > __val > __max ? __max: __val; }) > > /** > * clamp_val - return a value clamped to a given range using val's type > * @val: current value > * @min: minimum allowable value > * @max: maximum allowable value > * > * This macro does no typechecking and uses temporary variables of whatever > * type the input argument 'val' is. This is useful when val is an unisgned
unsigned
> * type and min and max are literals that will otherwise be assigned a signed > * integer type. > */ > #define clamp_val(val, min, max) ({ \ > typeof(val) __val = (val); \ > typeof(val) __min = (min); \ > typeof(val) __max = (max); \ > __val = __val < __min ? __min: __val; \ > __val > __max ? __max: __val; }) > > Comments? Please let me know if I got the kerneldoc format right.
Yes, it looks fine. Thanks.
-- ~Randy
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