/// <summary>
/// Allocates a new SPSCRingbuffer. Capacity will be set to a power of 2.
/// </summary>
public static UnsafeSPSCQueue *Allocate <T>(int capacity) where T : unmanaged
{
if (capacity < 1)
{
throw new ArgumentOutOfRangeException(nameof(capacity), string.Format(ThrowHelper.ArgumentOutOfRange_MustBePositive, nameof(capacity)));
}
// Requires one extra element to distinguish between empty and full queue.
capacity++;
int stride = sizeof(T);
var alignment = Memory.GetAlignment(stride);
var sizeOfQueue = Memory.RoundToAlignment(sizeof(UnsafeSPSCQueue), alignment);
var sizeOfArray = stride * capacity;
var ptr = Memory.MallocAndZero(sizeOfQueue + sizeOfArray, alignment);
UnsafeSPSCQueue *queue = (UnsafeSPSCQueue *)ptr;
// initialize fixed buffer from same block of memory as the stack
UnsafeBuffer.InitFixed(&queue->_items, (byte *)ptr + sizeOfQueue, capacity, stride);
queue->_headAndTail = new HeadAndTail();
queue->_typeHandle = typeof(T).TypeHandle.Value;
return(queue);
}
public static void Clear(UnsafeSPSCQueue *queue)
{
UDebug.Assert(queue != null);
UDebug.Assert(queue->_items.Ptr != null);
queue->_headAndTail = new HeadAndTail();
}
public static void Clear(UnsafeMPSCQueue *queue)
{
UDebug.Assert(queue != null);
UDebug.Assert(queue->_items.Ptr != null);
queue->_headAndTail = new HeadAndTail();
// Initialize the sequence number for each slot.
// This is used to synchronize between consumer and producer threads.
var offset = queue->_slotOffset;
var items = queue->_items;
for (int i = 0; i < queue->_items.Length; i++)
{
*(int *)items.Element(i, offset) = i;
}
}