yjinnlee / extractbits Goto Github PK

         bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
byte 0  |      Header       |  length |  field1 |
        -----------------------------------------
byte 1  |  field2                          | f3 |
        -----------------------------------------
byte 2  |         f3             |  field4      |
        -----------------------------------------
byte 3  |               field4                  |
        -----------------------------------------
byte 4  | field4   |       field5               |
        -----------------------------------------

    Header = extractByte(data, 0, 7, 4); // byteOffset 0, bitOffset 7, bitLength=4
    length = extractByte(data, 0, 3, 2);
    field1 = extractByte(data, 0, 1, 2);
    field2 = extractByte(data, 1, 7, 6);
    f3 = extractByte(data, 1, 0, 6);
    field4 = extractWord(data, 2, 2, 12);
    field5 = extractWord(data, 4, 5, 6);
    // dest will store data as LSByte order. 
    // byte 0 : byte 4(bit 6, 7) and byte 3(bit 5 4 3 2 1 0), 
    // byte 1 : byte 3(bit 7, 6) and byte 2(bit 2 1 0)
    uint8_t dest[100];
    field4lsb = extractBits(data, 2, 2, 12, dest);