PeterO.RandomGenerator.UniformLong C# (CSharp) Method

        public long UniformLong(long maxExclusive)
        {
            if (maxExclusive < 0) {
              throw new ArgumentException("maxExclusive (" + maxExclusive +
            ") is less than 0");
            }
              if (maxExclusive <= Int32.MaxValue) {
            return this.UniformInt((int)maxExclusive);
              }
              long lb = 0;
              long maxexc;
              var b = new byte[8];
              maxexc = (Int64.MaxValue / maxExclusive) * maxExclusive;
              while (true) {
            this.valueIrg.GetBytes(b, 0, 8);
            lb = b[0] & 0xffL;
            lb |= (b[1] & 0xffL) << 8;
            lb |= (b[2] & 0xffL) << 16;
            lb |= (b[3] & 0xffL) << 24;
            lb |= (b[4] & 0xffL) << 32;
            lb |= (b[5] & 0xffL) << 40;
            lb |= (b[6] & 0xffL) << 48;
            lb |= (b[7] & 0x7fL) << 56;
            if (lb < maxexc) {
              return lb % maxExclusive;
            }
              }
        }