/// <summary>
/// If the given <see cref="Int64BitSet"/> is large enough to hold
/// <paramref name="numBits"/>, returns the given <paramref name="bits"/>, otherwise returns a new
/// <see cref="Int64BitSet"/> which can hold the requested number of bits.
///
/// <para/>
/// <b>NOTE:</b> the returned bitset reuses the underlying <see cref="T:long[]"/> of
/// the given <paramref name="bits"/> if possible. Also, reading <see cref="Length"/> on the
/// returned bits may return a value greater than <paramref name="numBits"/>.
/// </summary>
public static Int64BitSet EnsureCapacity(Int64BitSet bits, long numBits)
{
if (numBits < bits.Length)
{
return(bits);
}
else
{
int numWords = Bits2words(numBits);
long[] arr = bits.GetBits();
if (numWords >= arr.Length)
{
arr = ArrayUtil.Grow(arr, numWords + 1);
}
return(new Int64BitSet(arr, arr.Length << 6));
}
}