re: lib/50009: strptime small enhancement

[matthew green <mrg%eterna.com.au@localhost>]

>  On Sun, Jun 28, 2015 at 07:50:00PM +0000, devnexen%gmail.com@localhost wrote:
>   > +#ifndef ISLEAPYEAR
>   > +#define ISLEAPYEAR(y) ((y % 400) == 0 && (y % 4) == 0 && (y % 100) != 0)
>   > +#endif
>  
>  ...this is wrong...

indeed, sys/clock.h has this:

63 /*
64  * This inline avoids some unnecessary modulo operations
65  * as compared with the usual macro:
66  *   ( ((year % 4) == 0 &&
67  *      (year % 100) != 0) ||
68  *     ((year % 400) == 0) )
69  * It is otherwise equivalent.
70  */
71 static inline int
72 is_leap_year(uint64_t year)
73 {
74         if ((year & 3) != 0)
75                 return 0;
76
77         if (__predict_false((year % 100) != 0))
78                 return 1;
79
80         return __predict_false((year % 400) == 0);
81 }

which should probably be used instead, for netbsd, or at
least the same expression in the comment.

(the macro above also doesn't work properly for various
inputs, like a good macro should.)


.mrg.