C# Byte To 4 Bit 用4bit儲存資料 可以節省一半空間

public static class HalfByteArray
{
    public static byte HalfByteAyGet(byte[] bAy, int idx)
    {
        int bIndex = idx / 2;
        if (idx % 2 == 0)
        {
            return (byte)(bAy[bIndex] >> 4);
        }
        else
        {
            return (byte)(bAy[bIndex] & 0b0000_1111);
        }
    }

    public static byte[] Byte2Half(byte[] og)
    {
        byte[] bAry = new byte[og.Length / 2];
        for (int i = 0; i < og.Length; i += 2)
        {
            byte HLv0 = og[i];
            byte HLv1 = og[i + 1];

            byte b = (byte)((HLv0 << 4) + HLv1);
            bAry[i / 2] = b;
        }
        return bAry;
    }

    public static void TestCase()
    {
        byte[] og = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 };
        byte[] halfB = Byte2Half(og);

        for (int i = 0; i < og.Length; i++)
        {
            byte back = HalfByteAyGet(halfB, i);
            UnityEngine.Assertions.Assert.AreEqual(back, og[i]);
        }
    }
}