C# 从 BitArray 转换为字节
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Convert from BitArray to Byte
提问by Graviton
I have a BitArraywith the length of 8, and I need a function to convert it to a byte. How to do it?
我有一个BitArray长度为 8 的 ，我需要一个函数将它转换为byte. 怎么做？
Specifically, I need a correct function of ConvertToByte:
具体来说，我需要一个正确的函数ConvertToByte：
BitArray bit = new BitArray(new bool[]
{
false, false, false, false,
false, false, false, true
});
//How to write ConvertToByte
byte myByte = ConvertToByte(bit);
var recoveredBit = new BitArray(new[] { myByte });
Assert.AreEqual(bit, recoveredBit);
采纳答案by Jon Skeet
This should work:
这应该有效：
byte ConvertToByte(BitArray bits)
{
if (bits.Count != 8)
{
throw new ArgumentException("bits");
}
byte[] bytes = new byte[1];
bits.CopyTo(bytes, 0);
return bytes[0];
}
回答by Caleb Vear
This should do the trick. However the previous answer is quite likely the better option.
这应该可以解决问题。然而，之前的答案很可能是更好的选择。
public byte ConvertToByte(BitArray bits)
{
if (bits.Count > 8)
throw new ArgumentException("ConvertToByte can only work with a BitArray containing a maximum of 8 values");
byte result = 0;
for (byte i = 0; i < bits.Count; i++)
{
if (bits[i])
result |= (byte)(1 << i);
}
return result;
}
In the example you posted the resulting byte will be 0x80. In other words the first value in the BitArray coresponds to the first bit in the returned byte.
在您发布的示例中，结果字节将为 0x80。换句话说，BitArray 中的第一个值对应于返回字节中的第一个位。
回答by tehvan
A poor man's solution:
一个穷人的解决方案：
protected byte ConvertToByte(BitArray bits)
{
if (bits.Count != 8)
{
throw new ArgumentException("illegal number of bits");
}
byte b = 0;
if (bits.Get(7)) b++;
if (bits.Get(6)) b += 2;
if (bits.Get(5)) b += 4;
if (bits.Get(4)) b += 8;
if (bits.Get(3)) b += 16;
if (bits.Get(2)) b += 32;
if (bits.Get(1)) b += 64;
if (bits.Get(0)) b += 128;
return b;
}
回答by Tedd Hansen
A bit late post, but this works for me:
发布有点晚，但这对我有用：
public static byte[] BitArrayToByteArray(BitArray bits)
{
byte[] ret = new byte[(bits.Length - 1) / 8 + 1];
bits.CopyTo(ret, 0);
return ret;
}
Works with:
适用于：
string text = "Test";
byte[] bytes = System.Text.Encoding.ASCII.GetBytes(text);
BitArray bits = new BitArray(bytes);
bytes[] bytesBack = BitArrayToByteArray(bits);
string textBack = System.Text.Encoding.ASCII.GetString(bytesBack);
// bytes == bytesBack
// text = textBack
.
.
回答by Dmitry Kakhovsky
That's should be the ultimate one. Works with any length of array.
那应该是终极的了。适用于任何长度的数组。
private List<byte> BoolList2ByteList(List<bool> values)
{
List<byte> ret = new List<byte>();
int count = 0;
byte currentByte = 0;
foreach (bool b in values)
{
if (b) currentByte |= (byte)(1 << count);
count++;
if (count == 7) { ret.Add(currentByte); currentByte = 0; count = 0; };
}
if (count < 7) ret.Add(currentByte);
return ret;
}
回答by NothinRandom
byte GetByte(BitArray input)
{
int len = input.Length;
if (len > 8)
len = 8;
int output = 0;
for (int i = 0; i < len; i++)
if (input.Get(i))
output += (1 << (len - 1 - i)); //this part depends on your system (Big/Little)
//output += (1 << i); //depends on system
return (byte)output;
}
Cheers!
干杯!
回答by underscore
Little endian byte array converter : First bit (indexed with "0") in the BitArray assumed to represents least significant bit (rightmost bit in the bit-octet) which interpreted as "zero" or "one" as binary.
小端字节数组转换器：假定 BitArray 中的第一位（以“0”为索引）表示最低有效位（位八位字节中的最右边位），其解释为“零”或“一”为二进制。
public static class BitArrayExtender {
public static byte[] ToByteArray( this BitArray bits ) {
const int BYTE = 8;
int length = ( bits.Count / BYTE ) + ( (bits.Count % BYTE == 0) ? 0 : 1 );
var bytes = new byte[ length ];
for ( int i = 0; i < bits.Length; i++ ) {
int bitIndex = i % BYTE;
int byteIndex = i / BYTE;
int mask = (bits[ i ] ? 1 : 0) << bitIndex;
bytes[ byteIndex ] |= (byte)mask;
}//for
return bytes;
}//ToByteArray
}//class
回答by Ali
In addition to @JonSkeet's answer you can use an Extension Method as below:
除了@JonSkeet 的回答之外，您还可以使用如下扩展方法：
public static byte ToByte(this BitArray bits)
{
if (bits.Count != 8)
{
throw new ArgumentException("bits");
}
byte[] bytes = new byte[1];
bits.CopyTo(bytes, 0);
return bytes[0];
}
And use like:
并使用如下：
BitArray foo = new BitArray(new bool[]
{
false, false, false, false,false, false, false, true
});
foo.ToByte();
回答by LoxLox
Unfortunately, the BitArray class is partially implemented in .Net Core class (UWP). For example BitArray class is unable to call the CopyTo() and Count() methods. I wrote this extension to fill the gap:
不幸的是，BitArray 类在 .Net Core 类 (UWP) 中部分实现。例如，BitArray 类无法调用 CopyTo() 和 Count() 方法。我写了这个扩展来填补空白：
public static IEnumerable<byte> ToBytes(this BitArray bits, bool MSB = false)
{
int bitCount = 7;
int outByte = 0;
foreach (bool bitValue in bits)
{
if (bitValue)
outByte |= MSB ? 1 << bitCount : 1 << (7 - bitCount);
if (bitCount == 0)
{
yield return (byte) outByte;
bitCount = 8;
outByte = 0;
}
bitCount--;
}
// Last partially decoded byte
if (bitCount < 7)
yield return (byte) outByte;
}
The method decodes the BitArray to a byte array using LSB (Less Significant Byte) logic. This is the same logic used by the BitArray class. Calling the method with the MSB parameter set on true will produce a MSB decoded byte sequence. In this case, remember that you maybe also need to reverse the final output byte collection.
该方法使用 LSB（低有效字节）逻辑将 BitArray 解码为字节数组。这与 BitArray 类使用的逻辑相同。在 MSB 参数设置为 true 的情况下调用该方法将产生一个 MSB 解码字节序列。在这种情况下，请记住您可能还需要反转最终输出字节集合。
