[C#]我自己写的一个对字节中每位进行修改值的函数

位操作方法

代码如下：

1. 设置字节中某位的值

static public Byte s_SetBit(Byte byTargetByte, int nTargetPos, int nValue)

{

	int nValueOfTargetPos = -1;



	if (nValue != 0 && nValue != 1)

	{

		return 0;

	}

	if (!(nTargetPos >= 0 && nTargetPos < 8))

	{

		return 0;

	}



	switch (nTargetPos)

	{

		case 0:

			nValueOfTargetPos = (byTargetByte >> 7) & 0x01;

			if (nValue == 1)

			{

				byTargetByte = Convert.ToByte(byTargetByte | 0x80);

			}

			else if (nValue == 0)

			{

				byTargetByte = Convert.ToByte(byTargetByte & 0x7f);

			}

			break;



		case 1:

			nValueOfTargetPos = (byTargetByte >> 6) & 0x01;



			if (nValue == 1)

			{

				byTargetByte = Convert.ToByte(byTargetByte | 0x40);

			}

			else if (nValue == 0)

			{

				byTargetByte = Convert.ToByte(byTargetByte & 0xbf);

			}

			break;



		case 2:

			nValueOfTargetPos = (byTargetByte >> 5) & 0x01;



			if (nValue == 1)

			{

				byTargetByte = Convert.ToByte(byTargetByte | 0x20);

			}

			else if (nValue == 0)

			{

				byTargetByte = Convert.ToByte(byTargetByte & 0xdf);

			}

			break;



		case 3:

			nValueOfTargetPos = (byTargetByte >> 4) & 0x01;



			if (nValue == 1)

			{

				byTargetByte = Convert.ToByte(byTargetByte | 0x10);

			}

			else if (nValue == 0)

			{

				byTargetByte = Convert.ToByte(byTargetByte & 0xef);

			}

			break;



		case 4:

			nValueOfTargetPos = (byTargetByte >> 3) & 0x01;



			if (nValue == 1)

			{

				byTargetByte = Convert.ToByte(byTargetByte | 0x08);

			}

			else if (nValue == 0)

			{

				byTargetByte = Convert.ToByte(byTargetByte & 0xf7);

			}

			break;



		case 5:

			nValueOfTargetPos = (byTargetByte >> 2) & 0x01;



			if (nValue == 1)

			{

				byTargetByte = Convert.ToByte(byTargetByte | 0x04);

			}

			else if (nValue == 0)

			{

				byTargetByte = Convert.ToByte(byTargetByte & 0xfb);

			}

			break;



		case 6:

			nValueOfTargetPos = (byTargetByte >> 1) & 0x01;



			if (nValue == 1)

			{

				byTargetByte = Convert.ToByte(byTargetByte | 0x02);

			}

			else if (nValue == 0)

			{

				byTargetByte = Convert.ToByte(byTargetByte & 0xfd);

			}

			break;



		case 7:

			nValueOfTargetPos = byTargetByte & 0x01;



			if (nValue == 1)

			{

				byTargetByte = Convert.ToByte(byTargetByte | 0x01);

			}

			else if (nValue == 0)

			{

				byTargetByte = Convert.ToByte(byTargetByte & 0xfe);

			}

			break;



		default:

			break;

	}



	if (nValueOfTargetPos != -1)

	{

		return byTargetByte;

	}

	else

	{

		return 0;

	}

}

测试案例：

把每位全为1的字节置0

Byte b = Convert.ToByte(0xff);

richTextBoxMain.Text = "byte初始状态： " + Convert.ToString(b, 2).PadLeft(8, '0') + "\r\n";

for (int i = 0; i < 8; i++)

{

	b = s_SetBit(b, i, 0);

	richTextBoxMain.Text += "byte修改第" + i + "位后的结果： ";

	richTextBoxMain.Text += Convert.ToString(b, 2).PadLeft(8, '0') + "\r\n";

}

结果如下：

byte初始状态： 11111111
byte修改第0位后的结果： 01111111
byte修改第1位后的结果： 00111111
byte修改第2位后的结果： 00011111
byte修改第3位后的结果： 00001111
byte修改第4位后的结果： 00000111
byte修改第5位后的结果： 00000011
byte修改第6位后的结果： 00000001
byte修改第7位后的结果： 00000000

 

 

2. 获得字节中某位的值

static public int s_GetBit(Byte byTargetByte, int nTargetPos)

{

	int nValue = -1;



	switch (nTargetPos)

	{

		case 0:

			nValue = (byTargetByte >> 7) & 0x01;

			break;

		case 1:

			nValue = (byTargetByte >> 6) & 0x01;

			break;

		case 2:

			nValue = (byTargetByte >> 5) & 0x01;

			break;

		case 3:

			nValue = (byTargetByte >> 4) & 0x01;

			break;

		case 4:

			nValue = (byTargetByte >> 3) & 0x01;

			break;

		case 5:

			nValue = (byTargetByte >> 2) & 0x01;

			break;

		case 6:

			nValue = (byTargetByte >> 1) & 0x01;

			break;

		case 7:

			nValue = byTargetByte & 0x01;

			break;

		default:

			break;

	}



	return nValue;

}