ref: 5df8776cafe4ed614fa3c4a0f9e1e4f01de228de
dir: /libsec/nfastrand.c/
#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) abort(); m = Maxrand - Maxrand % n; while((r = fastrand()) >= m) ; return r%n; }