/// <summary>
/// Set the most significate parity bit for supplied byte array.
/// </summary>
/// <param name="array">Input byte array.</param>
/// <param name="parity">Parity to set.</param>
/// <returns>New byte array with the correct parity.</returns>
public static byte[] SetParity(byte[] array, ParityOptions parity)
{
if (array == null)
throw new ArgumentNullException("array");
// An odd parity bit is set to 1 if the number of ones in a given set of bits is even
// (making the total number of ones, including the parity bit, odd).
// http://en.wikipedia.org/wiki/Parity_bit
// load the bytes into one contiguous bit array structure
BitArray bits = new BitArray(array);
byte[] buffer = Clone(array);
// two loops - the outer is to loop through the bytes
// and the inner is to loop through the bits in a particular byte
for (int i = 0; i < array.Length; i++)
{
int oneCount = 0;
// loop through the bits in the byte starting with
// the second bit and running to the 8th bit.
// (remember that the array is zero indexed so it is off by 1)
for (int j = 0; j < 7; j++)
{
if (bits[i * 8 + j] == true)
oneCount++;
}
// set the parity bit (bit position 0) for the byte now that we have the one's count
// if the number of one's is even then set to 1 ("true" for the BitArray)
// so that now the total number of bits (8) are now odd when added up
// the opposite is true for even parity
switch (parity)
{
case ParityOptions.Odd:
if (oneCount % 2 == 0)
buffer[i] |= (1 << 7);
else
buffer[i] &= unchecked((byte)(~(1 << 7)));
break;
case ParityOptions.Even:
if (oneCount % 2 == 0)
buffer[i] &= unchecked((byte)(~(1 << 7)));
else
buffer[i] |= (1 << 7);
break;
}
}
return buffer;
}
/// <summary>
/// Set the most significate parity bit for supplied byte array.
/// </summary>
/// <param name="array">Input byte array.</param>
/// <param name="parity">Parity to set.</param>
/// <returns>New byte array with the correct parity.</returns>
public static byte[] SetParity(byte[] array, ParityOptions parity)
{
if (array == null)
{
throw new ArgumentNullException("array");
}
// An odd parity bit is set to 1 if the number of ones in a given set of bits is even
// (making the total number of ones, including the parity bit, odd).
// http://en.wikipedia.org/wiki/Parity_bit
// load the bytes into one contiguous bit array structure
BitArray bits = new BitArray(array);
byte[] buffer = Clone(array);
// two loops - the outer is to loop through the bytes
// and the inner is to loop through the bits in a particular byte
for (int i = 0; i < array.Length; i++)
{
int oneCount = 0;
// loop through the bits in the byte starting with
// the second bit and running to the 8th bit.
// (remember that the array is zero indexed so it is off by 1)
for (int j = 0; j < 7; j++)
{
if (bits[i * 8 + j] == true)
{
oneCount++;
}
}
// set the parity bit (bit position 0) for the byte now that we have the one's count
// if the number of one's is even then set to 1 ("true" for the BitArray)
// so that now the total number of bits (8) are now odd when added up
// the opposite is true for even parity
switch (parity)
{
case ParityOptions.Odd:
if (oneCount % 2 == 0)
{
buffer[i] |= (1 << 7);
}
else
{
buffer[i] &= unchecked ((byte)(~(1 << 7)));
}
break;
case ParityOptions.Even:
if (oneCount % 2 == 0)
{
buffer[i] &= unchecked ((byte)(~(1 << 7)));
}
else
{
buffer[i] |= (1 << 7);
}
break;
}
}
return(buffer);
}
