//******************************************************************************************************//  DataPointScanner.cs - Gbtc////  Copyright © 2014, Grid Protection Alliance.  All Rights Reserved.////  Licensed to the Grid Protection Alliance (GPA) under one or more contributor license agreements. See//  the NOTICE file distributed with this work for additional information regarding copyright ownership.//  The GPA licenses this file to you under the MIT License (MIT), the "License"; you may//  not use this file except in compliance with the License. You may obtain a copy of the License at:////      http://www.opensource.org/licenses/MIT////  Unless agreed to in writing, the subject software distributed under the License is distributed on an//  "AS-IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. Refer to the//  License for the specific language governing permissions and limitations.////  Code Modification History://  ----------------------------------------------------------------------------------------------------//  09/22/2014 - Stephen C. Wills//       Generated original version of source code.////****************************************************************************************************** using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks; namespace GSF.Historian.Files{    /// <summary>    /// Scans an archive file for data points in a given time    /// range and returns them in the order that they are scanned.    /// </summary>    public class ArchiveFileScanner : IArchiveFileScanner    {        #region [ Members ]         // Fields        private ArchiveFileAllocationTable m_fileAllocationTable;        private IEnumerable<int> m_historianIDs;        private TimeTag m_startTime;        private TimeTag m_endTime;        private IDataPoint m_resumeFrom;        private EventHandler<EventArgs<Exception>> m_dataReadExceptionHandler;         #endregion         #region [ Constructors ]         #endregion         #region [ Properties ]         /// <summary>        /// Gets or sets the file allocation table of        /// the file that this scanner is reading from.        /// </summary>        public ArchiveFileAllocationTable FileAllocationTable        {            get            {                return m_fileAllocationTable;            }            set            {                m_fileAllocationTable = value;            }        }         /// <summary>        /// Gets or sets the collection of        /// point IDs to be scanned from the file.        /// </summary>        public IEnumerable<int> HistorianIDs        {            get            {                return m_historianIDs;            }            set            {                m_historianIDs = value;            }        }         /// <summary>        /// Gets or sets the minimum value of the timestamps        /// of the data points returned by the scanner.        /// </summary>        public TimeTag StartTime        {            get            {                return m_startTime;            }            set            {                m_startTime = value;            }        }         /// <summary>        /// Gets or sets the maximum value of the timestamps        /// of the data points returned by the scanner.        /// </summary>        public TimeTag EndTime        {            get            {                return m_endTime;            }            set            {                m_endTime = value;            }        }         /// <summary>        /// Gets or sets the data point from which to resume        /// the scan if it was interrupted by a rollover.        /// </summary>        public IDataPoint ResumeFrom        {            get            {                return m_resumeFrom;            }            set            {                m_resumeFrom = value;            }        }         /// <summary>        /// Gets or sets the handler used to handle        /// errors that occur while scanning the file.        /// </summary>        public EventHandler<EventArgs<Exception>> DataReadExceptionHandler        {            get            {                return m_dataReadExceptionHandler;            }            set            {                m_dataReadExceptionHandler = value;            }        }         #endregion         #region [ Methods ]         /// <summary>        /// Reads all <see cref="IDataPoint"/>s for the specified historian IDs.        /// </summary>        /// <returns>Each <see cref="IDataPoint"/> for the specified historian IDs.</returns>        public IEnumerable<IDataPoint> Read()        {            foreach (DataPointScanner scanner in GetScanners())            {                foreach (IDataPoint dataPoint in scanner.Read())                    yield return dataPoint;            }        }         // Gets the list of data point scanners used to        // scan the file for data belonging to this query.        private List<DataPointScanner> GetScanners()        {            List<DataPointScanner> dataPointScanners = new List<DataPointScanner>();            bool alreadyScanned = ((object)m_resumeFrom != null);             foreach (int historianID in m_historianIDs)            {                if (!alreadyScanned)                {                    dataPointScanners.Add(new DataPointScanner(m_fileAllocationTable, historianID, m_startTime, m_endTime, true, m_dataReadExceptionHandler));                }                else if (historianID == m_resumeFrom.HistorianID)                {                    dataPointScanners.Add(new DataPointScanner(m_fileAllocationTable, historianID, m_resumeFrom.Time, m_endTime, false, m_dataReadExceptionHandler));                    alreadyScanned = false;                }            }             return dataPointScanners;        }         #endregion    }}