// Parallelized merge sort algorithm. Uses Task infrastructure to spread sort across available resources
private static async Task ParallelSort(TDataStructure arrayToSort, int index, int length, TComparer comparer)
{
if (length < ParallelSortThreshold)
{
SequentialSort(arrayToSort, index, length, comparer);
}
else
{
TDataStructureAccessor accessor = default(TDataStructureAccessor);
int halfLen = length / 2;
TaskCompletionSource <bool> rightSortComplete = new System.Threading.Tasks.TaskCompletionSource <bool>();
_ = Task.Run(async() =>
{
await ParallelSort(arrayToSort, index + halfLen, length - halfLen, comparer);
rightSortComplete.SetResult(true);
});
T[] localCopyOfHalfOfArray = new T[halfLen];
accessor.Copy(arrayToSort, index, localCopyOfHalfOfArray, 0, halfLen);
await MergeSortCore <T, T[], ArrayAccessor <T>, TComparer, TCompareAsEqualAction> .ParallelSort(localCopyOfHalfOfArray, 0, halfLen, comparer);
await rightSortComplete.Task;
Merge(localCopyOfHalfOfArray, arrayToSort, index, halfLen, length, comparer);
}
}
// Parallelized merge sort algorithm. Uses Task infrastructure to spread sort across available resources
private static async Task ParallelSort(TDataStructure arrayToSort, int index, int length, TComparer comparer)
{
if (length < ParallelSortThreshold)
{
SequentialSort(arrayToSort, index, length, comparer);
}
else
{
TDataStructureAccessor accessor = default(TDataStructureAccessor);
int halfLen = length / 2;
Task rightSortTask = Task.Run(() => ParallelSort(arrayToSort, index + halfLen, length - halfLen, comparer));
T[] localCopyOfHalfOfArray = new T[halfLen];
accessor.Copy(arrayToSort, index, localCopyOfHalfOfArray, 0, halfLen);
await MergeSortCore <T, T[], ArrayAccessor <T>, TComparer, TCompareAsEqualAction> .ParallelSort(localCopyOfHalfOfArray, 0, halfLen, comparer);
await rightSortTask;
Merge(localCopyOfHalfOfArray, arrayToSort, index, halfLen, length, comparer);
}
}
