using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Xml.Serialization;

using System.Xml;

using System.Xml.Linq;

using System.IO;

using System.IO.Compression;

​

    //https://stackoverflow.com/questions/49139691/outofmemoryexception-while-reading-large-xml-file-in-c-sharp-windows-forms

​

    public class MeanVarianceTestResultsData

    {

        public int ResultsID { get; set; }

        public DateTime DateExecuted { get; set; }

        public string UserExecuted { get; set; }

        public string CorrectedMean { get; set; }

        public string CorrectedVariance { get; set; }

        public bool TestPassed { get; set; }

​

        public string TestResultImageFile { get; set; }

        public Stream TestResultImage { get; set; }

    }

​

    public static class MeanVarianceTestResultsDataExtensions

    {

        public static List<MeanVarianceTestResultsData> ReadResultListFrom(XmlReader reader, Func<MeanVarianceTestResultsData, Stream> openStream, Func<Stream, Stream> closeStream)

        {

            return reader.ReadSubtrees("TestResult").Select(r => ReadResultFrom(r, openStream, closeStream)).ToList();

        }

​

        public static MeanVarianceTestResultsData ReadResultFrom(XmlReader reader, Func<MeanVarianceTestResultsData, Stream> openStream, Func<Stream, Stream> closeStream)

        {

            if (reader == null || openStream == null)

                throw new ArgumentNullException();

            reader.MoveToContent();

            var result = new MeanVarianceTestResultsData();

            var isEmpty = reader.IsEmptyElement;

            // Read the root

            reader.Read();

            if (isEmpty)

                return result;

            while (!reader.EOF)

            {

                if (reader.NodeType == XmlNodeType.EndElement)

                {

                    reader.Read();

                    break;

                }

                else if (reader.NodeType != XmlNodeType.Element)

                    // Comment, text, CDATA, etc.

                    reader.Skip();

                else if (reader.Name == "ResultsID")

                    result.ResultsID = reader.ReadElementContentAsInt();

                else if (reader.Name == "DateExecuted")

                    result.DateExecuted = reader.ReadElementContentAsDateTime();

                else if (reader.Name == "UserExecuted")

                    result.UserExecuted = reader.ReadElementContentAsString();

                else if (reader.Name == "CorrectedMean")

                    result.CorrectedMean = reader.ReadElementContentAsString();

                else if (reader.Name == "TestPassed")

                    result.TestPassed = reader.ReadElementContentAsBoolean();

                else if (reader.Name == "TestResultImage")

                    result.TestResultImage = reader.ReadElementContentAsStream(() => openStream(result), closeStream);

                else

                    reader.Skip();

            }

            return result;

        }

    }

​

    public static class XmlReaderExtensions

    {

        public static Stream ReadElementContentAsStream(this XmlReader reader, Func<Stream> openStream, Func<Stream, Stream> closeStream)

        {

            if (reader == null || openStream == null)

                throw new ArgumentNullException();

            Stream stream = null;

            try

            {

                stream = openStream();

                byte[] buffer = new byte[4096];

                int readBytes = 0;

                while ((readBytes = reader.ReadElementContentAsBase64(buffer, 0, buffer.Length)) > 0)

                {

                    stream.Write(buffer, 0, readBytes);

                }

            }

            finally

            {

                if (closeStream != null && stream != null)

                    stream = closeStream(stream);

            }

            return stream;

        }

​

        public static IEnumerable<XmlReader> ReadSubtrees(this XmlReader reader, string name)

        {

            while (reader.ReadToFollowing(name))

            {

                using (var subReader = reader.ReadSubtree())

                    yield return subReader;

            }

        }

    }

​

    public class TestClass

    {

        public static void Test()

        {

            var fileName = "Question49159697.xml";

            var resultId = 49;

            var bytes = Enumerable.Range(0, 1024).Select(i => unchecked((byte)i)).ToArray();

​

            foreach (var xml in GetXml(resultId, bytes))

            {

                try

                {

                    Console.WriteLine("\nTesting XML: ");

                    Console.WriteLine(xml);

                    File.WriteAllText(fileName, xml);

                    Test(fileName, resultId, bytes);

                    TestToFile(fileName, resultId, bytes);

                }

                finally

                {

                    try

                    {

                        if (File.Exists(fileName))

                            File.Delete(fileName);

                    }

                    catch (Exception)

                    {

                    }

                }

            }

​

            Console.WriteLine("\nAll tests passed.");

        }

​

        static void TestToFile(string fileName, int resultId, byte[] bytes)

        {

            List<MeanVarianceTestResultsData> results;

            using (var reader = XmlReader.Create(fileName))

            {

                results = MeanVarianceTestResultsDataExtensions.ReadResultListFrom(

                    reader,

                    m => { m.TestResultImageFile = Path.GetTempFileName(); return File.Open(m.TestResultImageFile, FileMode.Create); },

                    s => { s.Dispose(); return null; });

            }

​

            Console.WriteLine("Read {0} results of type {1}", results.Count, typeof(MeanVarianceTestResultsData));

            Assert.IsTrue(results.Count == 2);

​

            foreach (var result in results)

            {

                Assert.IsTrue(File.ReadAllBytes(result.TestResultImageFile).SequenceEqual(bytes));

                Assert.IsTrue(result.ResultsID == resultId);

                File.Delete(result.TestResultImageFile);

            }

        }

​

        static void Test(string fileName, int resultId, byte[] bytes)

        {

            List<MeanVarianceTestResultsData> results;

            using (var reader = XmlReader.Create(fileName))

            {

                results = MeanVarianceTestResultsDataExtensions.ReadResultListFrom(reader, m => new MemoryStream(), s => { s.Position = 0; return s; });

            }

​

            Console.WriteLine("Read {0} results of type {1}", results.Count, typeof(MeanVarianceTestResultsData));

            Assert.IsTrue(results.Count == 2);

            foreach (var result in results)

            {

                Assert.IsTrue(((MemoryStream)result.TestResultImage).ToArray().SequenceEqual(bytes));

                Assert.IsTrue(result.ResultsID == resultId);

            }

        }

​

        static IEnumerable<string> GetXml(int resultId, byte [] bytes)

        {

            var template = @"<Root><SubRoot>

  <TestResult>

    <ResultsID>{0}</ResultsID>

    <DateExecuted>2018-02-20T09:36:12.787</DateExecuted>

    <UserExecuted>xxx</UserExecuted>

    <IrrelevantTag><IrrelevantTag>AA<n />{1}</IrrelevantTag>ss</IrrelevantTag>

    <CorrectedMean>1966.32245</CorrectedMean>

    <CorrectedVariance>19525.66320199{0}</CorrectedVariance>

    <TestPassed>true</TestPassed>

    <TestResultImage>{1}</TestResultImage>

    <IrrelevantTag><IrrelevantTag>AA<n />{1}</IrrelevantTag>ss</IrrelevantTag>

  </TestResult>

  <TestResult>Ignore This Text

    <!--Have a comment 

        on multiple lines  -->

    <ResultsID>{0}</ResultsID>

    <DateExecuted>2018-02-20T09:36:12.787</DateExecuted>

    <UserExecuted />

    <IrrelevantTag><IrrelevantTag>AA<n />{1}</IrrelevantTag>ss</IrrelevantTag>

    <CorrectedMean>1966.32245</CorrectedMean>

    <CorrectedVariance>19525.66320199{0}</CorrectedVariance>

    <TestPassed>true</TestPassed>

    <TestResultImage>{1}</TestResultImage>

    <IrrelevantTag><IrrelevantTag>AA<n />{1}</IrrelevantTag>ss><IrrelevantTag>AA<n />{1}</IrrelevantTag>ss

        <IrrelevantTag>AA<n />{1}</IrrelevantTag>ss><IrrelevantTag>AA<n />{1}</IrrelevantTag>ss

    </IrrelevantTag>

  </TestResult>

</SubRoot></Root>";

            var xml = string.Format(template, resultId, Convert.ToBase64String(bytes));

            return new[]

            {

                xml,

                XDocument.Parse(xml).ToString(SaveOptions.DisableFormatting),

                XDocument.Parse(xml).ToString(),

            };

        }

    }

​

    public class AssertionFailedException : System.Exception

    {

        public AssertionFailedException() : base() { }

​

        public AssertionFailedException(string s) : base(s) { }

    }

​

    public static class Assert

    {

        public static void IsTrue(bool value)

        {

            IsTrue(value, "failed");

        }

​

        public static void IsTrue(bool value, string message)

        {

            if (value == false)

                throw new AssertionFailedException(message ?? "failed");

        }

    }

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Roslyn 2.0 Compiler; Environment version: " + Environment.Version);

            Console.WriteLine();

​

            try

            {

                TestClass.Test();

            }

            catch (Exception ex)

            {

                Console.WriteLine("Uncaught exception: ");

                Console.WriteLine(ex);

                throw;

            }

        }

    }

​

    static class Path

    {

        // Work around the fact that Path.GetTempFileName() does not work on dotnetfiddle

        public static string GetTempFileName()

        {

            return Guid.NewGuid().ToString();

        }

    }

​