Comment lire les 4 premiers et les 4 derniers bits d'octets?

dans une structure pratique:

Utilisation h3> xxx pré>

code h3> xxx pré>

bonus: tableau (non testé)

Si vous avez besoin d'utiliser un tableau de ces demi-octets, cela simplifiera l'accès: P>

public class HalvedByteArray
{
    public int Capacity { get; private set; }
    public HalvedByte[] Array { get; private set; }

    public byte this[int index]
    {
        get
        {
            if (index < 0 || index >= Capacity)
            {
                throw new IndexOutOfRangeException();
            }

            var hb = Array[index / 2];

            return (index % 2 == 0) ? hb.Low : hb.High;
        }
        set
        {
            if (index < 0 || index >= Capacity)
            {
                throw new IndexOutOfRangeException();
            }

            var hb = Array[index / 2];

            if (index % 2 == 0)
            {
                hb.Low = value;
            }
            else
            {
                hb.High = value;
            }
        }
    }

    public HalvedByteArray(int capacity)
    {
        if (capacity < 0)
        {
            throw new ArgumentException("Capacity must be positive.", "capacity");
        }

        Capacity = capacity;
        Array = new HalvedByte[capacity / 2];
    }
}

Je préférerais simplement utiliser cela -

byte a = 68;
byte high_bits = a>>4;
byte low_bits = a&15;

Méthode simple pour le faire.

Exemple Utilisez: P>

A: 10101110 P>

B: 00001110 P>

Obtenez 4 bits de la dernière Cette sortie est comme B P>

GetBitRange (10101110, 0, 4); P>

//gets a bits from a byte, and return a byte of the new bits
byte getBitRange(byte data, int start, int _end){

//shift binary to starting point of range
byte shifted = (data >> start);

//calculate range length (+1 for 0 index)
int rangeLength = (_end-start)+1;

//get binary mask based on range length 
byte maskBinary;
 
switch (rangeLength){
case 1: maskBinary = 0b00000001; break;
case 2: maskBinary = 0b00000011; break;
case 3: maskBinary = 0b00000111; break;
case 4: maskBinary = 0b00001111; break;
case 5: maskBinary = 0b00011111; break;
case 6: maskBinary = 0b00111111; break;
case 7: maskBinary = 0b01111111; break;
case 8: maskBinary = 0b11111111; break;
default:
  // default statements
  Serial.println("Error: Range length too long!!");
}

//cancel out 
byte finalByte = (shifted & maskBinary);

return finalByte;
}