/// <summary>
/// Returns the memory to write to that is at least the requested size.
/// </summary>
/// <param name="sizeHint">The minimum length of the returned memory.</param>
/// <returns>The memory block of at least the size <paramref name="sizeHint"/>.</returns>
/// <exception cref="OutOfMemoryException">The requested buffer size is not available.</exception>
public Span <T> GetSpan(int sizeHint = 0)
{
if (sizeHint < 0)
{
throw new ArgumentOutOfRangeException(nameof(sizeHint));
}
Span <T> result;
int? newSize;
if (extraBuffer.IsEmpty)
{
newSize = IGrowableBuffer <T> .GetBufferSize(sizeHint, initialBuffer.Length, position);
// need to copy initial buffer
if (newSize.HasValue)
{
extraBuffer = allocator.Invoke(newSize.GetValueOrDefault(), false);
initialBuffer.CopyTo(extraBuffer.Memory.Span);
initialBuffer.Clear();
result = extraBuffer.Memory.Span;
}
else
{
result = initialBuffer;
}
}
else
{
newSize = IGrowableBuffer <T> .GetBufferSize(sizeHint, extraBuffer.Length, position);
// no need to copy initial buffer
if (newSize.HasValue)
{
var newBuffer = allocator.Invoke(newSize.GetValueOrDefault(), false);
extraBuffer.Memory.CopyTo(newBuffer.Memory);
extraBuffer.Dispose();
extraBuffer = newBuffer;
}
result = extraBuffer.Memory.Span;
}
return(result.Slice(position));
}