public int[] Allocate(int blockCount)
{
if (blockCount <= 0)
{
throw new ArgumentOutOfRangeException(nameof(blockCount));
}
var allocatedFromIndexBlocks = new int[0];
lock (lockObject)
{
var allocatedFromIndexBlockCount = Math.Min(ReleasedBlockCount, blockCount);
if (allocatedFromIndexBlockCount > 0)
{
allocatedFromIndexBlocks = new int[allocatedFromIndexBlockCount];
var position = ReleasedBlockCount - allocatedFromIndexBlockCount;
blockStream.Read(position, allocatedFromIndexBlocks);
blockStream.Write(position, new int[allocatedFromIndexBlockCount]);
ReleasedBlockCount -= allocatedFromIndexBlockCount;
}
var leftBlocks = blockCount - allocatedFromIndexBlockCount;
if (leftBlocks > 0)
{
var blocks = storage.Extend(leftBlocks);
return(allocatedFromIndexBlocks.Concat(blocks).ToArray());
}
}
EraseBlocks(allocatedFromIndexBlocks);
return(allocatedFromIndexBlocks);
}