/// <summary>
/// This method will spread out the work items--like dealing cards around the table, you only get every other K'th card,
/// where K is the number of people, when batchCount=1. (Or else you get sets of batchCount-contiguous cards).
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="enumerable"></param>
/// <param name="pieceIndexRangeCollection"></param>
/// <param name="pieceCount"></param>
/// <param name="batchCount"></param>
/// <param name="skipListOrNull"></param>
/// <returns>The item and it's original index in the enumerable.</returns>
public static IEnumerable <KeyValuePair <T, long> > DivideWork <T>(IEnumerable <T> enumerable, RangeCollection pieceIndexRangeCollection,
long pieceCount, long batchCount, RangeCollection skipListOrNull)
{
if (pieceIndexRangeCollection == null)
{
throw new ArgumentNullException("pieceIndexRangeCollection");
}
Helper.CheckCondition(batchCount > 0, string.Format(CultureInfo.CurrentCulture, Properties.Resource.BatchCountCondition));
long pieceIndex = 0;
long batchIndex = 0;
bool inRange = pieceIndexRangeCollection.Contains(pieceIndex);
foreach (var tAndRowIndex in UseSkipList(enumerable, skipListOrNull))
{
if (inRange)
{
yield return(tAndRowIndex);
}
++batchIndex;
if (batchIndex == batchCount)
{
batchIndex = 0;
pieceIndex = (pieceIndex + 1) % pieceCount;
inRange = pieceIndexRangeCollection.Contains(pieceIndex);
}
}
}
private static IEnumerable <KeyValuePair <T, long> > UseSkipList <T>(IEnumerable <T> enumerable, RangeCollection skipListOrNull)
{
long rowIndex = -1;
foreach (T t in enumerable)
{
++rowIndex;
if (null != skipListOrNull && skipListOrNull.Contains(rowIndex))
{
continue;
}
yield return(new KeyValuePair <T, long>(t, rowIndex));
}
}