org.bouncycastle.pqc.math.linearalgebra.RandUtils Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of bouncycastle Show documentation

The Bouncy Castle Java APIs for CMS, PKCS, EAC, TSP, CMP, CRMF, OCSP, and certificate generation. This jar contains APIs for JDK 1.5 and up. The APIs can be used in conjunction with a JCE/JCA provider such as the one provided with the Bouncy Castle Cryptography APIs.

There is a newer version: 1.2.2.1-jre17

Show newest version

package org.bouncycastle.pqc.math.linearalgebra;

import java.security.SecureRandom;

public class RandUtils
{
    static int nextInt(SecureRandom rand, int n)
    {

        if ((n & -n) == n)  // i.e., n is a power of 2
        {
            return (int)((n * (long)(rand.nextInt() >>> 1)) >> 31);
        }

        int bits, value;
        do
        {
            bits = rand.nextInt() >>> 1;
            value = bits % n;
        }
        while (bits - value + (n - 1) < 0);

        return value;
    }
}