[英]How to get the value of a bit at a certain positions from a byte array?
byte[] sample = new byte[]{10,20,30};
-值是6位,從第三位開始(從右到左)
新的byte [] {10,20,30}看起來像是“ 00001010 00010100 00011110”(應該按字節順序排列),所以我需要“ 00001010 00010100 * 000111 * 10”-我的值是7
基於幫助的解決方案( Yaur的答案1),僅改變了方向
public static bool GetValue(byte[] data, int position)
{
var bytePos = data.Length - 1 - position / 8;//right -> left
//var bytePos = position / 8;//left -> right
var bitPos = position % 8;
return ((data[bytePos] & (1 << bitPos)) != 0);//right -> left
//return ((data[bytePos] & (1 << (7 - bitPos))) != 0); //left -> right
}
public static long GetValue(byte[] data, int position, int length)
{
if (length > 62)
{
throw new ArgumentException("not going to work properly with 63 bits if the first bit is 1");
}
long retv = 0;
for (int i = position + length - 1; i > position - 1; i--)
//for(int i = position;i<position+length;i++)//left -> right
{
if (GetValue(data, i)) retv |= 1;
retv = retv << 1;
}
retv = retv >> 1;
return retv;
}
這應該適用於大多數輸入:
public bool GetValue(byte[] data, int position)
{
var bytePos = position / 8;
var bitPos = position % 8;
return ((data[bytePos] & (1 << bitPos))!=0)
// depending on the order in which you expect the bits you might need this instead
//return ((data[bytePos] & (1 << (7-bitPos)))!=0)
}
public long GetValue(byte[] data, int position, int length)
{
if(length > 62)
{
throw new ArgumentException("not going to work properly with 63 bits if the first bit is 1");
}
long retv=0;
for(int i = position;i<position+length;i++)
{
if(GetValue(data,i)
{
retv |=1;
}
retv = retv << 1;
}
retv = retv >> 1;
}
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.