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- #include <u.h>
- #include <libc.h>
- #include <libsec.h>
- #define Maxrand ((1UL<<31)-1)
- ulong
- nfastrand(ulong n)
- {
- ulong m, r;
-
- /*
- * set m to the maximum multiple of n <= 2^31-1
- * so we want a random number < m.
- */
- if(n > Maxrand)
- sysfatal("nfastrand: n too large");
- m = Maxrand - Maxrand % n;
- while((r = fastrand()) >= m)
- ;
- return r%n;
- }
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