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;
}