UserRangePartitioner.cs

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// 
// UserRangePartitioner.cs
//  
// Author:
//       Jérémie "Garuma" Laval <jeremie.laval@gmail.com>
// 
// Copyright (c) 2010 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 || UNITY_5_3_OR_NEWER

using System;
using System.Threading;
using System.Collections.Generic;

namespace System.Collections.Concurrent.Partitioners
{
    internal class UserRangePartitioner : OrderablePartitioner<Tuple<int,  int>>
    {
        readonly int start;
        readonly int end;
        readonly int rangeSize;

        public UserRangePartitioner (int start, int end, int rangeSize) : base (true, true, true)
        {
            this.start = start;
            this.end = end;
            this.rangeSize = rangeSize;
        }
        
        public override IList<IEnumerator<KeyValuePair<long, Tuple<int, int>>>> GetOrderablePartitions (int partitionCount)
        {
            if (partitionCount <= 0)
                throw new ArgumentOutOfRangeException ("partitionCount");
            
            int currentIndex = 0;
            Func<int> getNextIndex = () => Interlocked.Increment (ref currentIndex) - 1;

            var enumerators = new IEnumerator<KeyValuePair<long, Tuple<int, int>>>[partitionCount];
            for (int i = 0; i < partitionCount; i++)
                enumerators[i] = GetEnumerator (getNextIndex);

            return enumerators;
        }
        
        IEnumerator<KeyValuePair<long, Tuple<int, int>>> GetEnumerator (Func<int> getNextIndex)
        {
            while (true) {
                int index = getNextIndex ();
                int sliceStart = index * rangeSize + start;

                if (sliceStart >= end)
                    break;

                yield return new KeyValuePair<long, Tuple<int, int>> (index, Tuple.Create (sliceStart, Math.Min (end, sliceStart + rangeSize)));
                sliceStart += rangeSize;
            }
        }
    }

    internal class UserLongRangePartitioner : OrderablePartitioner<Tuple<long,  long>>
    {
        readonly long start;
        readonly long end;
        readonly long rangeSize;

        public UserLongRangePartitioner (long start, long end, long rangeSize) : base (true, true, true)
        {
            this.start = start;
            this.end = end;
            this.rangeSize = rangeSize;
        }
        
        public override IList<IEnumerator<KeyValuePair<long, Tuple<long, long>>>> GetOrderablePartitions (int partitionCount)
        {
            if (partitionCount <= 0)
                throw new ArgumentOutOfRangeException ("partitionCount");
            
            long currentIndex = 0;
            Func<long> getNextIndex = () => Interlocked.Increment (ref currentIndex) - 1;

            var enumerators = new IEnumerator<KeyValuePair<long, Tuple<long, long>>>[partitionCount];
            for (int i = 0; i < partitionCount; i++)
                enumerators[i] = GetEnumerator (getNextIndex);

            return enumerators;
        }
        
        IEnumerator<KeyValuePair<long, Tuple<long, long>>> GetEnumerator (Func<long> getNextIndex)
        {
            while (true) {
                long index = getNextIndex ();
                long sliceStart = index * rangeSize + start;

                if (sliceStart >= end)
                    break;

                yield return new KeyValuePair<long, Tuple<long, long>> (index, Tuple.Create (sliceStart, Math.Min (end, sliceStart + rangeSize)));
                sliceStart += rangeSize;
            }
        }
    }
}
#endif