Synopsis

FileBack implements an array whose backing store is on disk.
Arrays based on IList may theoretically contain upto 2G elements.
However, long before reaching that limit, memory constraints and virtual memory page thrashing already cause performance issues.
By storing Serializable elements on disk, large arrays can be handled, at the cost of having to read and write files.

Usage

ValueTypeList
- Use ValueTypeList to store value types such as int.
- As int has a fixed size, the element indexed is easily addressed.
ReferenceEnumerator
- Use ReferenceEnumerator to store reference types.
- Reference types are serialized to the file store.
- A ValueTypeList is used to store the index to the variably sized reference type.

License

This code is released under a BSD styled license.

Source

BaseCollection.cs

/*
 * Copyright (c) 2011 Bumble Bee Laboratories Pte Ltd. All Rights Reserved.
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for NON-COMMERCIAL or COMMERCIAL purposes and
 * without fee is hereby granted, provided that this copyright notice is kept
 * intact.
 *
 * BUMBLE BEE LABORATORIES PTE LTD MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. BUMBLE BEE LABORATORIES PTE LTD SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
 *
 * THIS SOFTWARE IS NOT DESIGNED OR INTENDED FOR USE OR RESALE AS ON-LINE
 * CONTROL EQUIPMENT IN HAZARDOUS ENVIRONMENTS REQUIRING FAIL-SAFE
 * PERFORMANCE, SUCH AS IN THE OPERATION OF NUCLEAR FACILITIES, AIRCRAFT
 * NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL, DIRECT LIFE
 * SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH THE FAILURE OF THE
 * SOFTWARE COULD LEAD DIRECTLY TO DEATH, PERSONAL INJURY, OR SEVERE
 * PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH RISK ACTIVITIES").  BUMBLE BEE LABORATORIES PTE LTD
 * SPECIFICALLY DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR
 * HIGH RISK ACTIVITIES.
 */

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;

namespace FileBack
{
    public class BaseCollection: IDisposable
    {
        protected FileStream m_backingStream;

        public BaseCollection()
        {
            m_backingStream = FileUtil.CreateTemporaryFileStream();
        }

        #region IDisposable Members

        private bool m_disposed = false;

        public void Dispose()
        {
            Dispose(true);
        }

        protected virtual void Dispose(bool disposing)
        {
            // Check to see if Dispose has already been called.
            if (!this.m_disposed)
            {
                // If disposing equals true, dispose all managed
                // and unmanaged resources.
                if (disposing)
                {
                    // Dispose managed resources.
                    m_backingStream.Dispose();
                }

                // Call the appropriate methods to clean up
                // unmanaged resources here.
                // If disposing is false,
                // only the following code is executed.

                // Note disposing has been done.
                m_disposed = true;
            }
        }

        ~BaseCollection()
        {
            Dispose(false);
        }

        #endregion
    }
}

BinaryUtil.cs

/*
 * Copyright (c) 2011 Bumble Bee Laboratories Pte Ltd. All Rights Reserved.
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for NON-COMMERCIAL or COMMERCIAL purposes and
 * without fee is hereby granted, provided that this copyright notice is kept
 * intact.
 *
 * BUMBLE BEE LABORATORIES PTE LTD MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. BUMBLE BEE LABORATORIES PTE LTD SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
 *
 * THIS SOFTWARE IS NOT DESIGNED OR INTENDED FOR USE OR RESALE AS ON-LINE
 * CONTROL EQUIPMENT IN HAZARDOUS ENVIRONMENTS REQUIRING FAIL-SAFE
 * PERFORMANCE, SUCH AS IN THE OPERATION OF NUCLEAR FACILITIES, AIRCRAFT
 * NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL, DIRECT LIFE
 * SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH THE FAILURE OF THE
 * SOFTWARE COULD LEAD DIRECTLY TO DEATH, PERSONAL INJURY, OR SEVERE
 * PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH RISK ACTIVITIES").  BUMBLE BEE LABORATORIES PTE LTD
 * SPECIFICALLY DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR
 * HIGH RISK ACTIVITIES.
 */

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;

namespace FileBack
{
    class BinaryUtil
    {
        public static byte[] toByteArray<T>(T value) where T : struct
        {
            int size = Marshal.SizeOf(value);

            byte[] buffer = new byte[size];

            GCHandle handle = GCHandle.Alloc(buffer, GCHandleType.Pinned);
            try
            {
                Marshal.StructureToPtr(value, handle.AddrOfPinnedObject(), false);
            }
            finally
            {
                handle.Free();
            }

            return buffer;
        }

        public static T fromByteArray<T>(byte[] buffer) where T : struct
        {
            GCHandle handle = GCHandle.Alloc(buffer, GCHandleType.Pinned);
            try
            {
                T value = (T)Marshal.PtrToStructure(handle.AddrOfPinnedObject(), typeof(T));
                return value;
            }
            finally
            {
                handle.Free();
            }
        }
    }
}

File.cs

/*
 * Copyright (c) 2011 Bumble Bee Laboratories Pte Ltd. All Rights Reserved.
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for NON-COMMERCIAL or COMMERCIAL purposes and
 * without fee is hereby granted, provided that this copyright notice is kept
 * intact.
 *
 * BUMBLE BEE LABORATORIES PTE LTD MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. BUMBLE BEE LABORATORIES PTE LTD SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
 *
 * THIS SOFTWARE IS NOT DESIGNED OR INTENDED FOR USE OR RESALE AS ON-LINE
 * CONTROL EQUIPMENT IN HAZARDOUS ENVIRONMENTS REQUIRING FAIL-SAFE
 * PERFORMANCE, SUCH AS IN THE OPERATION OF NUCLEAR FACILITIES, AIRCRAFT
 * NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL, DIRECT LIFE
 * SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH THE FAILURE OF THE
 * SOFTWARE COULD LEAD DIRECTLY TO DEATH, PERSONAL INJURY, OR SEVERE
 * PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH RISK ACTIVITIES").  BUMBLE BEE LABORATORIES PTE LTD
 * SPECIFICALLY DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR
 * HIGH RISK ACTIVITIES.
 */

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;

namespace FileBack
{
    class FileUtil
    {
        public static FileStream CreateTemporaryFileStream()
        {
            FileStream tempFS;
            string path = Path.Combine(Path.GetTempPath(),Guid.NewGuid().ToString() + ".tmp");
            //Console.WriteLine("temp file " + path);
            tempFS = File.Create(path, 65536, FileOptions.DeleteOnClose);
            return tempFS;
        }
    }
}

ReferenceEnumerator.cs

/*
 * Copyright (c) 2011 Bumble Bee Laboratories Pte Ltd. All Rights Reserved.
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for NON-COMMERCIAL or COMMERCIAL purposes and
 * without fee is hereby granted, provided that this copyright notice is kept
 * intact.
 *
 * BUMBLE BEE LABORATORIES PTE LTD MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. BUMBLE BEE LABORATORIES PTE LTD SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
 *
 * THIS SOFTWARE IS NOT DESIGNED OR INTENDED FOR USE OR RESALE AS ON-LINE
 * CONTROL EQUIPMENT IN HAZARDOUS ENVIRONMENTS REQUIRING FAIL-SAFE
 * PERFORMANCE, SUCH AS IN THE OPERATION OF NUCLEAR FACILITIES, AIRCRAFT
 * NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL, DIRECT LIFE
 * SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH THE FAILURE OF THE
 * SOFTWARE COULD LEAD DIRECTLY TO DEATH, PERSONAL INJURY, OR SEVERE
 * PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH RISK ACTIVITIES").  BUMBLE BEE LABORATORIES PTE LTD
 * SPECIFICALLY DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR
 * HIGH RISK ACTIVITIES.
 */

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace FileBack
{
    class ReferenceEnumerator<T> : IEnumerator<T>
    {
        ReferenceList<T> m_parent;
        T m_current;
        int m_index = -1;

        public ReferenceEnumerator(ReferenceList<T> parent)
        {
            m_parent = parent;
        }

        protected T getCurrent()
        {
            if (m_index == -1)
            {
                throw new InvalidOperationException();
            }
            else
            {
                return m_current;
            }
        }

        #region IEnumerator<T> Members

        public T Current
        {
            get {
                return getCurrent();
            }
        }

        #endregion

        #region IDisposable Members

        public void Dispose()
        {
        }

        #endregion

        #region IEnumerator Members

        object System.Collections.IEnumerator.Current
        {
            get { return getCurrent(); }
        }

        public bool MoveNext()
        {
            int i = m_index + 1;

            if (i >= m_parent.Count())
            {
                return false;
            }
            else
            {
                m_index = i;
                m_current = m_parent[i];
            }

            return true;
        }

        public void Reset()
        {
            m_index = -1;
        }

        #endregion
    }
}

ReferenceList.cs

/*
 * Copyright (c) 2011 Bumble Bee Laboratories Pte Ltd. All Rights Reserved.
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for NON-COMMERCIAL or COMMERCIAL purposes and
 * without fee is hereby granted, provided that this copyright notice is kept
 * intact.
 *
 * BUMBLE BEE LABORATORIES PTE LTD MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. BUMBLE BEE LABORATORIES PTE LTD SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
 *
 * THIS SOFTWARE IS NOT DESIGNED OR INTENDED FOR USE OR RESALE AS ON-LINE
 * CONTROL EQUIPMENT IN HAZARDOUS ENVIRONMENTS REQUIRING FAIL-SAFE
 * PERFORMANCE, SUCH AS IN THE OPERATION OF NUCLEAR FACILITIES, AIRCRAFT
 * NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL, DIRECT LIFE
 * SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH THE FAILURE OF THE
 * SOFTWARE COULD LEAD DIRECTLY TO DEATH, PERSONAL INJURY, OR SEVERE
 * PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH RISK ACTIVITIES").  BUMBLE BEE LABORATORIES PTE LTD
 * SPECIFICALLY DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR
 * HIGH RISK ACTIVITIES.
 */

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace FileBack
{
    public class ReferenceList<T> : BaseCollection, IList<T>
    {
        protected ValueTypeList<long> m_index = new ValueTypeList<long>();  // index into file for serialized object
        protected System.Runtime.Serialization.Formatters.Binary.BinaryFormatter m_serdes = new System.Runtime.Serialization.Formatters.Binary.BinaryFormatter();

        #region IList<T> Members

        public int IndexOf(T item)
        {
            throw new NotImplementedException();
        }

        public void Insert(int index, T item)
        {
            throw new NotImplementedException();
        }

        public void RemoveAt(int index)
        {
            throw new NotImplementedException();
        }

        /// <summary>
        /// To update a member of an object in the collection, don't do list[i].member = value.
        /// Instead, copy into p = list[i], do p.member = value, and assign list[i] = p.
        /// Then the list item will be updated.
        /// </summary>
        /// <param name="index"></param>
        /// <returns></returns>
        public T this[int index]
        {
            get
            {
                long offset = m_index[index];
                m_backingStream.Position = offset;
                T item = (T)m_serdes.Deserialize(m_backingStream);
                return item;
            }
            set
            {
                long offset = m_backingStream.Length;
                m_backingStream.Position = offset;
                m_serdes.Serialize(m_backingStream, value);
                m_index[index] = offset;
            }
        }

        #endregion

        #region ICollection<T> Members

        public void Add(T item)
        {
            long offset = m_backingStream.Length;
            m_backingStream.Position = offset;
            m_serdes.Serialize(m_backingStream, item);
            m_index.Add(offset);
        }

        public void Clear()
        {
            m_backingStream.SetLength(0);
            m_index.Clear();
        }

        public bool Contains(T item)
        {
            throw new NotImplementedException();
        }

        public void CopyTo(T[] array, int arrayIndex)
        {
            throw new NotImplementedException();
        }

        public int Count
        {
            get { return m_index.Count(); }
        }

        public bool IsReadOnly
        {
            get { return false; }
        }

        public bool Remove(T item)
        {
            throw new NotImplementedException();
        }

        #endregion

        #region IEnumerable<T> Members

        public IEnumerator<T> GetEnumerator()
        {
            return new ReferenceEnumerator<T>(this);
        }

        #endregion

        #region IEnumerable Members

        System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
        {
            return new ReferenceEnumerator<T>(this);
        }

        #endregion
    }
}

ValueTypeEnumerator.cs

/*
 * Copyright (c) 2011 Bumble Bee Laboratories Pte Ltd. All Rights Reserved.
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for NON-COMMERCIAL or COMMERCIAL purposes and
 * without fee is hereby granted, provided that this copyright notice is kept
 * intact.
 *
 * BUMBLE BEE LABORATORIES PTE LTD MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. BUMBLE BEE LABORATORIES PTE LTD SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
 *
 * THIS SOFTWARE IS NOT DESIGNED OR INTENDED FOR USE OR RESALE AS ON-LINE
 * CONTROL EQUIPMENT IN HAZARDOUS ENVIRONMENTS REQUIRING FAIL-SAFE
 * PERFORMANCE, SUCH AS IN THE OPERATION OF NUCLEAR FACILITIES, AIRCRAFT
 * NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL, DIRECT LIFE
 * SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH THE FAILURE OF THE
 * SOFTWARE COULD LEAD DIRECTLY TO DEATH, PERSONAL INJURY, OR SEVERE
 * PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH RISK ACTIVITIES").  BUMBLE BEE LABORATORIES PTE LTD
 * SPECIFICALLY DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR
 * HIGH RISK ACTIVITIES.
 */

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace FileBack
{
    class ValueTypeEnumerator<T> : IEnumerator<T> where T : struct
    {
        ValueTypeList<T> m_parent;
        T m_current = default(T);
        int m_index = -1;

        public ValueTypeEnumerator(ValueTypeList<T> parent)
        {
            m_parent = parent;
        }

        protected T getCurrent()
        {
            if (m_index == -1)
            {
                throw new InvalidOperationException();
            }
            else
            {
                return m_current;
            }
        }

        #region IEnumerator<T> Members

        public T Current
        {
            get {
                return getCurrent();
            }
        }

        #endregion

        #region IDisposable Members

        public void Dispose()
        {
        }

        #endregion

        #region IEnumerator Members

        object System.Collections.IEnumerator.Current
        {
            get {
                return getCurrent();    
            }
        }

        public bool MoveNext()
        {
            int i = m_index + 1;

            if (i >= m_parent.Count())
            {
                return false;
            }
            else
            {
                m_index = i;
                m_current = m_parent[i];
            }

            return true;
        }

        public void Reset()
        {
            m_index = -1;
        }

        #endregion
    }
}

ValueTypeList.cs

/*
 * Copyright (c) 2011 Bumble Bee Laboratories Pte Ltd. All Rights Reserved.
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for NON-COMMERCIAL or COMMERCIAL purposes and
 * without fee is hereby granted, provided that this copyright notice is kept
 * intact.
 *
 * BUMBLE BEE LABORATORIES PTE LTD MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. BUMBLE BEE LABORATORIES PTE LTD SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
 *
 * THIS SOFTWARE IS NOT DESIGNED OR INTENDED FOR USE OR RESALE AS ON-LINE
 * CONTROL EQUIPMENT IN HAZARDOUS ENVIRONMENTS REQUIRING FAIL-SAFE
 * PERFORMANCE, SUCH AS IN THE OPERATION OF NUCLEAR FACILITIES, AIRCRAFT
 * NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL, DIRECT LIFE
 * SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH THE FAILURE OF THE
 * SOFTWARE COULD LEAD DIRECTLY TO DEATH, PERSONAL INJURY, OR SEVERE
 * PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH RISK ACTIVITIES").  BUMBLE BEE LABORATORIES PTE LTD
 * SPECIFICALLY DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR
 * HIGH RISK ACTIVITIES.
 */

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;

namespace FileBack
{
    public class ValueTypeList<T> : BaseCollection, IList<T> where T: struct
    {
        protected int m_elementSize;

        public ValueTypeList() : base()
        {
            T sample = new T();
            m_elementSize = Marshal.SizeOf(sample);
            //Console.WriteLine(sample.GetType().ToString() + "=" + m_elementSize);
        }

        protected long getFileOffset(int index)
        {
            if (index >= 0)
            {
                return (long)index * (long)m_elementSize;
            }
            else
            {
                throw new ArgumentOutOfRangeException("index out of range: " + index);
            }
        }

        #region ICollection<T> Members

        public void Add(T item)
        {
            m_backingStream.Seek(0, System.IO.SeekOrigin.End);

            byte[] buffer = BinaryUtil.toByteArray<T>(item);

            m_backingStream.Write(buffer, 0, buffer.Count());
        }

        public void Clear()
        {
            m_backingStream.SetLength(0);
        }

        public bool Contains(T item)
        {
            throw new NotImplementedException();
        }

        public void CopyTo(T[] array, int arrayIndex)
        {
            throw new NotImplementedException();
        }

        public int Count
        {
            get {
                long count = m_backingStream.Length;

                count = count / m_elementSize;

                if (count > int.MaxValue)
                {
                    throw new ArgumentOutOfRangeException("the returned count is " + count + ", which would not fit in an int");
                }

                return (int) count;
            }
        }

        public bool IsReadOnly
        {
            get { return false; }
        }

        public bool Remove(T item)
        {
            throw new NotImplementedException();
        }

        #endregion

        #region IEnumerable<T> Members

        public IEnumerator<T> GetEnumerator()
        {
            return new ValueTypeEnumerator<T>(this);
        }

        #endregion

        #region IEnumerable Members

        System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
        {
            return new ValueTypeEnumerator<T>(this);
        }

        #endregion

        #region IList<T> Members

        public int IndexOf(T item)
        {
            throw new NotImplementedException();
        }

        public void Insert(int index, T item)
        {
            throw new NotImplementedException();
        }

        public void RemoveAt(int index)
        {
            throw new NotImplementedException();
        }

        public T this[int index]
        {
            get
            {
                long offset = getFileOffset(index);
                m_backingStream.Seek(offset, System.IO.SeekOrigin.Begin);
                byte[] buffer = new byte[m_elementSize];
                int r = m_backingStream.Read(buffer,0,m_elementSize);
                if (r != m_elementSize)
                {
                    throw new System.IO.IOException("unable to read " + m_elementSize + " bytes from backing store");
                }
                T value = BinaryUtil.fromByteArray<T>(buffer);
                return value;
            }
            set
            {
                long offset = getFileOffset(index);
                m_backingStream.Seek(offset, System.IO.SeekOrigin.Begin);
                byte[] buffer = BinaryUtil.toByteArray<T>(value);
                m_backingStream.Write(buffer, 0, m_elementSize);
            }
        }

        #endregion
    }
}

Created on 06 Apr 2011

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