/// <summary>
/// Clear out all the named fields
/// </summary>
public void ClearFields()
{
_fields.Clear();
_bits = new BitString();
}
/// <summary>
/// Concatenation of two BitStrings
/// </summary>
/// <param name="b1">A BitString that will be left concatenated with b2</param>
/// <param name="b2">A BitString that will be right concatenated with b1</param>
/// <returns></returns>
public static BitString operator +(BitString b1, BitString b2) // input; BitString object to concatenate
{
// Declare new bit string to hold result
Int32 newLength = b1.Length + b2.Length;
BitString newBitString = new BitString(newLength);
// First, check if both operands are empty strings
if (newLength == 0)
{
return(newBitString); // Return an empty string
}
// Now check if this object is empty
if (b1.Length == 0)
{
return(new BitString(b2)); // No need to concatenate -- just return copy of right operand
}
// Now check if the right operand is empty
if (b2.Length == 0)
{
return(new BitString(b1)); // No need to concatenate -- just return copy of left operand
}
// Otherwise start concatenation by copying this object into new bit string
for (Int32 i = 0; i < b1.StorageSize; i++)
{
newBitString._buffer[i] = b1._buffer[i];
}
// Now we need to concatenate the right operand onto the new bit string
// Calculate beginning left operand index
Int64 leftPos = b1.StorageSize - 1;
Int64 rightPos;
if ((b1.Length & 31) != 0) // Shifting needed since this object is not multiple of 32 bits
{
// Calculate the number of places to shift
Int32 shiftAmount = 32 - (b1.Length & 31); // Amount of bit shifting required
// Calculate the Left Mask
Int64 leftMask = -9223372036854775808; // Mask for tempLeft
leftMask >>= (b1.Length & 31) - 1;
// Calculate the Right Mask
const UInt64 rightMask = 0x00000000FFFFFFFF; // Mask for tempRight
// Now copy the right operand word by word to the end of the new bit string
// along with the required shifting, masking and ORing operations
for (rightPos = 0; rightPos < b2.StorageSize; rightPos++)
{
// grab right most word from left bit string
UInt64 tempLeft = newBitString._buffer[leftPos]; // Temporary buffer variable
tempLeft <<= 32;
// mask out the lower trash bits
tempLeft &= (UInt64)leftMask;
// grab left most byte from right operand
UInt64 tempRight = b2._buffer[rightPos]; // Temporary buffer variable
tempRight &= rightMask;
tempRight <<= shiftAmount;
// Now concatenate the words into temporary buffer by OR'ing them
tempLeft |= tempRight;
// Now copy this into the new bit string
Byte[] byteArray = BitConverter.GetBytes(tempLeft);
// Check for special end case of 1-word copy
if (rightPos == b2.StorageSize - 1 && (b2.Length & 31) != 0 &&
shiftAmount >= (b2.Length & 31))
{
UInt32 t1 = BitConverter.ToUInt32(byteArray, 4);
newBitString._buffer[leftPos] = t1; // Little Endian Machine
}
else // Normal 2 word copying
{
UInt32 t0 = BitConverter.ToUInt32(byteArray, 0);
UInt32 t1 = BitConverter.ToUInt32(byteArray, 4);
newBitString._buffer[leftPos] = t1; // Little Endian Machine
newBitString._buffer[leftPos + 1] = t0; // Little Endian Machine
}
// Adjust indices
++leftPos;
} // end for
}
else // No bit shifting needed since this object is multiple of 32 bits
{
// Pad the right operand to the new bit string
for (rightPos = 0; rightPos < b2.StorageSize; rightPos++)
{
newBitString._buffer[leftPos + 1] = b2._buffer[rightPos];
++leftPos;
}
}
// return the new bit string
return(newBitString);
}
/// <summary>
/// Initiates an empty BitField
/// </summary>
public BitField()
{
_bits = new BitString();
_fields = new OrderedDictionary();
}