c# - 包含最小值和最大值的 RNGCryptoServiceProvider

Question

我需要一个方法，它返回从最小值到最大值的随机数，包括这两个数字。我在文章 .NET Matters: Tales from the CryptoRandom 中找到了一些代码来自 Stephen Toub 和 Shawn Farkas，该方法看起来像这样:

// Note - maxValue is excluded!
public static int GetRandomIntBetween(int minValue, int maxValue)
{
    if (minValue > maxValue) throw new ArgumentOutOfRangeException("minValue");
    if (minValue == maxValue) return minValue;

    var rng = new RNGCryptoServiceProvider();
    var uint32Buffer = new byte[4];
    long diff = maxValue - minValue;

    while (true)
    {
        rng.GetBytes(uint32Buffer);
        uint rand = BitConverter.ToUInt32(uint32Buffer, 0);
        const long max = (1 + (long)int.MaxValue);
        long remainder = max % diff;
        if (rand < max - remainder)
        {
            return (int)(minValue + (rand % diff));
        }
    }
}

我试图使 maxValue 包含在内:

public static int GetRandomIntBetween(int minValue, int maxValue)
{
    if (minValue > maxValue) throw new ArgumentOutOfRangeException("minValue");
    if (minValue == maxValue) return minValue;

    // Make maxValue inclusive.
    maxValue++;

    var rng = new RNGCryptoServiceProvider();
    var uint32Buffer = new byte[4];
    long diff = maxValue - minValue;

    while (true)
    {
        rng.GetBytes(uint32Buffer);
        uint rand = BitConverter.ToUInt32(uint32Buffer, 0);
        const long max = (1 + (long)int.MaxValue);
        long remainder = max % diff;
        if (rand < max - remainder)
        {
            return (int)(minValue + (rand % diff));
        }
    }
}

看起来很奇怪，但似乎我可以保持前两个检查不变，即使语义略有不同，它仍然有效。结果数据看起来也不错。我是不是漏掉了什么或者找零钱可以吗？

PS - 我问这个是因为生成随机数显然是一件非常微妙的事情，我想确保我的方法是正确的。

Answer 1

Look at my solution (click there)

您可以向类中添加其他方法:

public int NextInclusive(int minValue, int maxValue) {
        return Next(minValue, maxValue + 1);
}