private static IOrderedDataProducer <TSource> OrderBy <TSource, TKey>(IDataProducer <TSource> source, DotNet20.Func <TSource, TKey> selector, IComparer <TKey> comparer, bool descending)
{
source.ThrowIfNull("source");
comparer.ThrowIfNull("comparer");
IComparer <TSource> itemComparer = new ProjectionComparer <TSource, TKey>(selector, comparer);
if (descending)
{
itemComparer = itemComparer.Reverse();
}
// first, discard any existing "order by"s by going back to the producer
IOrderedDataProducer <TSource> orderedProducer;
bool first = true;
while ((orderedProducer = source as IOrderedDataProducer <TSource>) != null)
{
if (first)
{
// keep the top-most comparer to enforce a balanced sort
itemComparer = new LinkedComparer <TSource>(itemComparer, orderedProducer.Comparer);
first = false;
}
source = orderedProducer.BaseProducer;
}
return(new OrderedDataProducer <TSource>(source, itemComparer));
}
private static IOrderedDataProducer <TSource> ThenBy <TSource, TKey>(IOrderedDataProducer <TSource> source, DotNet20.Func <TSource, TKey> selector, IComparer <TKey> comparer, bool descending)
{
comparer.ThrowIfNull("comparer");
IComparer <TSource> itemComparer = new ProjectionComparer <TSource, TKey>(selector, comparer);
if (descending)
{
itemComparer = itemComparer.Reverse();
}
itemComparer = new LinkedComparer <TSource>(source.Comparer, itemComparer);
return(new OrderedDataProducer <TSource>(source, itemComparer));
}
/// <summary>
/// Sorts the elements in the entire System.Collections.Generic.List{T} using
/// a projection.
/// </summary>
/// <param name="source">Data source</param>
/// <param name="selector">The projection to use to obtain values for comparison</param>
/// <param name="comparer">The comparer to use to compare projected values (on null to use the default comparer)</param>
/// <param name="descending">Should the list be sorted ascending or descending?</param>
public static void Sort <T, TValue>(this List <T> source, DotNet20.Func <T, TValue> selector, IComparer <TValue> comparer, bool descending)
{
if (source == null)
{
throw new ArgumentNullException("source");
}
if (comparer == null)
{
comparer = Comparer <TValue> .Default;
}
IComparer <T> itemComparer = new ProjectionComparer <T, TValue>(selector, comparer);
if (descending)
{
itemComparer = itemComparer.Reverse();
}
source.Sort(itemComparer);
}
/// <summary>
/// Sorts the elements in the entire System.Collections.Generic.List{T} using
/// a projection.
/// </summary>
/// <param name="source">Data source</param>
/// <param name="selector">The projection to use to obtain values for comparison</param>
/// <param name="comparer">The comparer to use to compare projected values (on null to use the default comparer)</param>
/// <param name="descending">Should the list be sorted ascending or descending?</param>
public static void Sort <T, TValue>(this List <T> source, Func <T, TValue> selector, IComparer <TValue> comparer, bool descending)
{
switch (source)
{
case null:
throw new ArgumentNullException("source");
}
comparer = comparer switch
{
null => Comparer <TValue> .Default,
_ => comparer
};
IComparer <T> itemComparer = new ProjectionComparer <T, TValue>(selector, comparer);
switch (descending)
{
case true:
itemComparer = itemComparer.Reverse();
break;
}
source.Sort(itemComparer);
}