/// <summary>
/// Performs a circular shift on the bits in the current <see cref="BitArray" />.
/// </summary>
/// <param name="target">
/// The current <see cref="BitArray" />.
/// </param>
/// <param name="direction">
/// A direction to shift the bits in the current <see cref="BitArray" />. The default value is
/// <see cref="BitShiftDirection.Right" />.
/// </param>
/// <param name="bitShiftCount">
/// The number of bits to shift by.
/// </param>
/// <exception cref="ArgumentOutOfRangeException">
/// The value of <paramref name="bitShiftCount" /> is less than zero.
/// </exception>
public static BitArray PerformCircularShift(this BitArray target, BitShiftDirection direction, Int32 bitShiftCount)
{
var arrayLength = target.Length;
if (arrayLength < 2)
{
return(target);
}
Int32 directionalBitShiftCount;
switch (direction)
{
case BitShiftDirection.Left:
// Sign the shift count negative for left shifts.
directionalBitShiftCount = (bitShiftCount.RejectIf().IsLessThan(0, nameof(bitShiftCount)) * -1);
break;
case BitShiftDirection.Right:
// Sign the shift count positive for right shifts.
directionalBitShiftCount = bitShiftCount.RejectIf().IsLessThan(0, nameof(bitShiftCount));
break;
default:
goto case BitShiftDirection.Right;
}
var newBitArray = new BitArray(arrayLength, false);
for (var i = 0; i < arrayLength; i++)
{
newBitArray.Set(DetermineNewCircularPosition(i, arrayLength, directionalBitShiftCount), target.Get(i));
}
return(newBitArray);
}
/// <summary>
/// Performs a circular shift on the bits in the current <see cref="Byte" /> array.
/// </summary>
/// <param name="target">
/// The current <see cref="Byte" /> array.
/// </param>
/// <param name="direction">
/// A direction to shift the bits in the current <see cref="Byte" /> array. The default value is
/// <see cref="BitShiftDirection.Right" />.
/// </param>
/// <param name="bitShiftCount">
/// The number of bits to shift by.
/// </param>
/// <exception cref="ArgumentOutOfRangeException">
/// The value of <paramref name="direction" /> is equal to <see cref="BitShiftDirection.Unspecified" /> and/or the value of
/// <paramref name="bitShiftCount" /> is less than zero.
/// </exception>
public static Byte[] PerformCircularBitShift(this Byte[] target, BitShiftDirection direction, Int32 bitShiftCount)
{
direction.RejectIf().IsEqualToValue(BitShiftDirection.Unspecified, nameof(direction));
if (target.Length == 0)
{
return(target);
}
var collectionByteLength = target.Length;
var collectionBitLength = (collectionByteLength * 8);
var simplifiedBitShiftCount = (bitShiftCount.RejectIf().IsLessThan(0, nameof(bitShiftCount)) % collectionBitLength);
if (simplifiedBitShiftCount == 0)
{
return(target);
}
var simplifiedByteShiftCount = (simplifiedBitShiftCount / 8);
var bitShiftRemainder = (simplifiedBitShiftCount % 8);
var outputBuffer = new Byte[collectionByteLength];
Int32 headIndex;
Int32 readIndex;
Int32 writeIndex;
switch (direction)
{
case BitShiftDirection.Left:
headIndex = simplifiedByteShiftCount;
if (bitShiftRemainder == 0)
{
for (readIndex = headIndex, writeIndex = 0; readIndex < collectionByteLength; readIndex++, writeIndex++)
{
outputBuffer[writeIndex] = target[readIndex];
}
for (readIndex = 0; readIndex < headIndex; readIndex++, writeIndex++)
{
outputBuffer[writeIndex] = target[readIndex];
}
}
else
{
Byte leftElement;
Byte rightElement;
for (readIndex = headIndex, writeIndex = 0; readIndex < collectionByteLength; readIndex++, writeIndex++)
{
leftElement = target[readIndex];
rightElement = target[readIndex == (collectionByteLength - 1) ? 0 : (readIndex + 1)];
outputBuffer[writeIndex] = unchecked ((Byte)(leftElement >> bitShiftRemainder | rightElement << (8 - bitShiftRemainder)));
}
for (readIndex = 0; readIndex < headIndex; readIndex++, writeIndex++)
{
leftElement = target[readIndex];
rightElement = target[readIndex + 1];
outputBuffer[writeIndex] = unchecked ((Byte)(leftElement >> bitShiftRemainder | rightElement << (8 - bitShiftRemainder)));
}
}
break;
case BitShiftDirection.Right:
headIndex = (collectionByteLength - simplifiedByteShiftCount);
if (bitShiftRemainder == 0)
{
for (readIndex = headIndex, writeIndex = 0; readIndex < collectionByteLength; readIndex++, writeIndex++)
{
outputBuffer[writeIndex] = target[readIndex];
}
for (readIndex = 0; readIndex < headIndex; readIndex++, writeIndex++)
{
outputBuffer[writeIndex] = target[readIndex];
}
}
else
{
Byte leftElement;
Byte rightElement;
for (readIndex = headIndex, writeIndex = 0; readIndex < collectionByteLength; readIndex++, writeIndex++)
{
leftElement = target[readIndex - 1];
rightElement = target[readIndex];
outputBuffer[writeIndex] = unchecked ((Byte)(leftElement >> (8 - bitShiftRemainder) | rightElement << bitShiftRemainder));
}
for (readIndex = 0; readIndex < headIndex; readIndex++, writeIndex++)
{
leftElement = target[readIndex == 0 ? (collectionByteLength - 1) : (readIndex - 1)];
rightElement = target[readIndex];
outputBuffer[writeIndex] = unchecked ((Byte)(leftElement >> (8 - bitShiftRemainder) | rightElement << bitShiftRemainder));
}
}
break;
default:
throw new ArgumentException($"{direction} is not a supported {nameof(BitShiftDirection)}.", nameof(direction));
}
return(outputBuffer);
}
/// <summary> /// Converts the current <see cref="BitShiftDirection" /> to an array of bytes. /// </summary> /// <param name="target"> /// The current instance of the <see cref="BitShiftDirection" />. /// </param> /// <returns> /// An array of bytes representing the current <see cref="BitShiftDirection" />. /// </returns> public static Byte[] ToByteArray(this BitShiftDirection target) => BitConverter.GetBytes((Int32)target);
