Partitioner.cs

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// 
// Partitioner.cs
//  
// Author:
//       Jérémie "Garuma" Laval <jeremie.laval@gmail.com>
// 
// Copyright (c) 2009 Jérémie "Garuma" Laval
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#if NET_4_0

using System;
using System.Collections.Generic;

namespace System.Collections.Concurrent
{
    using Partitioners;

    public static class Partitioner
    {
        public static OrderablePartitioner<TSource> Create<TSource> (IEnumerable<TSource> source)
        {
            IList<TSource> tempIList = source as IList<TSource>;
            if (tempIList != null)
                return Create (tempIList, true);
            
            return new EnumerablePartitioner<TSource> (source);
        }
        
        public static OrderablePartitioner<TSource> Create<TSource> (TSource[] array, bool loadBalance)
        {
            return Create ((IList<TSource>)array, loadBalance);
        }
        
        public static OrderablePartitioner<TSource> Create<TSource> (IList<TSource> list, bool loadBalance)
        {
            return new ListPartitioner<TSource> (list);
        }
        
        public static OrderablePartitioner<Tuple<int, int>> Create (int fromInclusive,
                                                                    int toExclusive)
        {
            // This formula that is somewhat non-straighforward was guessed based on MS output
            int rangeSize = (toExclusive - fromInclusive) / (Environment.ProcessorCount * 3);
            if (rangeSize < 1)
                rangeSize = 1;

            return Create (fromInclusive, toExclusive, rangeSize);
        }

        public static OrderablePartitioner<Tuple<int, int>> Create (int fromInclusive,
                                                                    int toExclusive,
                                                                    int rangeSize)
        {
            if (fromInclusive >= toExclusive)
                throw new ArgumentOutOfRangeException ("toExclusive");
            if (rangeSize <= 0)
                throw new ArgumentOutOfRangeException ("rangeSize");

            return new UserRangePartitioner (fromInclusive, toExclusive, rangeSize);
        }

        public static OrderablePartitioner<Tuple<long, long>> Create (long fromInclusive,
                                                                      long toExclusive)
        {
            long rangeSize = (toExclusive - fromInclusive) / (Environment.ProcessorCount * 3);
            if (rangeSize < 1)
                rangeSize = 1;

            return Create (fromInclusive, toExclusive, rangeSize);
        }

        public static OrderablePartitioner<Tuple<long, long>> Create (long fromInclusive,
                                                                      long toExclusive,
                                                                      long rangeSize)
        {
            if (rangeSize <= 0)
                throw new ArgumentOutOfRangeException ("rangeSize");
            if (fromInclusive >= toExclusive)
                throw new ArgumentOutOfRangeException ("toExclusive");

            return new UserLongRangePartitioner (fromInclusive, toExclusive, rangeSize);
        }
        
#if NET_4_5
        [MonoTODO]
        public static OrderablePartitioner<TSource> Create<TSource> (IEnumerable<TSource> source,
                                         EnumerablePartitionerOptions partitionerOptions)
        {
            throw new NotImplementedException ();
        }
#endif
    }
    
    public abstract class Partitioner<TSource>
    {
        protected Partitioner ()
        {
            
        }
        
        public virtual IEnumerable<TSource> GetDynamicPartitions ()
        {
            if (!SupportsDynamicPartitions)
                throw new NotSupportedException ();
            
            return null;
        }
        
        public abstract IList<IEnumerator<TSource>> GetPartitions (int partitionCount);
        
        public virtual bool SupportsDynamicPartitions {
            get {
                return false;
            }
        }
    }
}
#endif