using System;

using System.Collections.Generic;

namespace ServiceStack

{

public static class CollectionExtensions

{

public static ICollection<T> CreateAndPopulate<T>(Type ofCollectionType, T[] withItems)

{

if (withItems == null)

return null;

if (ofCollectionType == null)

return new List<T>(withItems);

var genericType = ofCollectionType.FirstGenericType();

var genericTypeDefinition = genericType != null

? genericType.GetGenericTypeDefinition()

: null;

#if !XBOX

if (genericTypeDefinition == typeof(HashSet<>))

return new HashSet<T>(withItems);

#endif

if (genericTypeDefinition == typeof(LinkedList<>))

return new LinkedList<T>(withItems);

var collection = (ICollection<T>)ofCollectionType.CreateInstance();

foreach (var item in withItems)

{

collection.Add(item);

}

return collection;

}

public static T[] ToArray<T>(this ICollection<T> collection)

{

var to = new T[collection.Count];

collection.CopyTo(to, 0);

return to;

}

public static object Convert<T>(object objCollection, Type toCollectionType)

{

var collection = (ICollection<T>) objCollection;

var to = new T[collection.Count];

collection.CopyTo(to, 0);

return CreateAndPopulate(toCollectionType, to);

}

}

}