public unsafe void ResizeToAtLeast(ref RawBuffer buffer, int targetSize, int copyCount)
{
Debug.Assert(copyCount <= buffer.Length, "Can't copy more than the capacity of the buffer.");
Debug.Assert(copyCount <= targetSize, "Can't copy more than the target size.");
//Only do anything if the new size is actually different from the current size.
targetSize = 1 << (SpanHelper.GetContainingPowerOf2(targetSize));
if (buffer.Allocated)
{
DecomposeId(buffer.Id, out var powerIndex, out var slotIndex);
var currentSize = 1 << powerIndex;
if (currentSize != targetSize || pools[powerIndex].GetStartPointerForSlot(slotIndex) != buffer.Memory)
{
TakeAtLeast(targetSize, out var newBuffer);
Buffer.MemoryCopy(buffer.Memory, newBuffer.Memory, buffer.Length, copyCount);
pools[powerIndex].Return(slotIndex);
buffer = newBuffer;
}
else
{
//While the allocation size is equal to the target size, the buffer might not be.
//Fortunately, if the allocation stays the same size and the buffer start is at its original location, we can skip doing any work.
//(With more work, you could expand *backwards*, we just didn't bother since this is exceptionally rare anyway.
//The typed codepath doesn't bother doing this at all, and that's fine.)
buffer.Length = targetSize;
}
}
else
{
//Nothing to return or copy.
TakeAtLeast(targetSize, out buffer);
}
}
public static int GetCapacityForCount <T>(int count)
{
if (count == 0)
{
count = 1;
}
return((1 << SpanHelper.GetContainingPowerOf2(count * Unsafe.SizeOf <T>())) / Unsafe.SizeOf <T>());
}
public PowerPool(int power, int minimumBlockSize, int expectedPooledCount)
{
Power = power;
SuballocationSize = 1 << power;
BlockSize = Math.Max(SuballocationSize, minimumBlockSize);
Slots = new ManagedIdPool(expectedPooledCount);
SuballocationsPerBlock = BlockSize / SuballocationSize;
SuballocationsPerBlockShift = SpanHelper.GetContainingPowerOf2(SuballocationsPerBlock);
SuballocationsPerBlockMask = (1 << SuballocationsPerBlockShift) - 1;
Blocks = new Block[1];
BlockCount = 0;
#if DEBUG
outstandingIds = new HashSet <int>();
#if LEAKDEBUG
outstandingAllocators = new Dictionary <string, HashSet <int> >();
#endif
#endif
}
public unsafe void Take(out RawBuffer buffer)
{
var slot = Slots.Take();
var blockIndex = slot >> SuballocationsPerBlockShift;
if (blockIndex >= Blocks.Length)
{
Array.Resize(ref Blocks, 1 << SpanHelper.GetContainingPowerOf2(blockIndex + 1));
}
if (blockIndex >= BlockCount)
{
#if DEBUG
for (int i = 0; i < blockIndex; ++i)
{
Debug.Assert(Blocks[i].Allocated, "If a block index is found to exceed the current block count, then every block preceding the index should be allocated.");
}
#endif
BlockCount = blockIndex + 1;
Debug.Assert(!Blocks[blockIndex].Allocated);
Blocks[blockIndex] = new Block(BlockSize);
}
var indexInBlock = slot & SuballocationsPerBlockMask;
buffer = new RawBuffer(Blocks[blockIndex].Allocate(indexInBlock, SuballocationSize), SuballocationSize, (Power << IdPowerShift) | slot);
Debug.Assert(buffer.Id >= 0 && Power >= 0 && Power < 32, "Slot/power should be safely encoded in a 32 bit integer.");
#if DEBUG
const int maximumOutstandingCount = 1 << 20;
Debug.Assert(outstandingIds.Count <= maximumOutstandingCount,
$"Do you actually truly really need to have {maximumOutstandingCount} allocations taken from this power pool, or is this a memory leak?");
Debug.Assert(outstandingIds.Add(slot), "Should not be able to request the same slot twice.");
#if LEAKDEBUG
var allocator = new StackTrace().ToString();
if (!outstandingAllocators.TryGetValue(allocator, out var idsForAllocator))
{
idsForAllocator = new HashSet <int>();
outstandingAllocators.Add(allocator, idsForAllocator);
}
Debug.Assert(idsForAllocator.Count < (1 << 25), "Do you actually have that many allocations for this one allocator?");
idsForAllocator.Add(slot);
#endif
#endif
}
public void TakeAtLeast(int count, out RawBuffer buffer)
{
TakeForPower(SpanHelper.GetContainingPowerOf2(count), out buffer);
}
/// <summary>
/// Gets the capacity allocated for a power.
/// </summary>
/// <param name="power">Power to check.</param>
/// <returns>Allocated capacity for the given power.</returns>
public int GetCapacityForPower(int power)
{
SpanHelper.ValidatePower(power);
return(pools[power].BlockCount * pools[power].BlockSize);
}
/// <summary>
/// Ensures that the pool associated with a given power has at least a certain amount of capacity, measured in bytes.
/// </summary>
/// <param name="byteCount">Minimum number of bytes to require for the power pool.</param>
/// <param name="power">Power associated with the pool to check.</param>
public void EnsureCapacityForPower(int byteCount, int power)
{
SpanHelper.ValidatePower(power);
ValidatePinnedState(true);
pools[power].EnsureCapacity(byteCount);
}
