Data: Matlab: delayed deserialization, allow matrix file to contain matrices of multiple types

src/Data/Matlab/MatlabFile.cs

@@ -4,7 +4,7 @@
 // http://github.com/mathnet/mathnet-numerics
 // http://mathnetnumerics.codeplex.com
 //
-// Copyright (c) 2009-2013 Math.NET
+// Copyright (c) 2009-2014 Math.NET
 //
 // Permission is hereby granted, free of charge, to any person
 // obtaining a copy of this software and associated documentation
@@ -37,13 +37,12 @@ namespace MathNet.Numerics.Data.Matlab
     /// <summary>
     /// Represents a MATLAB file
     /// </summary>
-    /// <typeparam name="TDataType">The data type of the matrix to return.</typeparam>
-    internal class MatlabFile<TDataType> where TDataType : struct, IEquatable<TDataType>, IFormattable
+    internal class MatlabFile
     {
         /// <summary>
         /// Matrices in a MATLAB file stored as 1-D arrays
         /// </summary>
-        readonly IDictionary<string, Matrix<TDataType>> _matrices = new SortedList<string, Matrix<TDataType>>();
+        readonly IDictionary<string, byte[]> _matrices = new SortedList<string, byte[]>();
 
         /// <summary>
         /// Gets or sets the header text.
@@ -55,32 +54,26 @@ namespace MathNet.Numerics.Data.Matlab
         /// Gets or sets the first name of the matrix.
         /// </summary>
         /// <value>The first name of the matrix.</value>
-        internal string FirstMatrixName { get; set; }
+        internal string FirstMatrixName { get; private set; }
 
-        /// <summary>
-        /// Gets the first matrix.
-        /// </summary>
-        /// <value>The first matrix.</value>
-        internal Matrix<TDataType> FirstMatrix
+        internal ICollection<string> MatrixNames
         {
-            get
-            {
-                if (string.IsNullOrEmpty(FirstMatrixName) || !_matrices.ContainsKey(FirstMatrixName))
-                {
-                    return null;
-                }
+            get { return _matrices.Keys; }
+        }
 
-                return _matrices[FirstMatrixName];
+        internal void Add(string name, byte[] data)
+        {
+            if (FirstMatrixName == null)
+            {
+                FirstMatrixName = name;
             }
+
+            _matrices.Add(name, data);
         }
 
-        /// <summary>
-        /// Gets the matrices.
-        /// </summary>
-        /// <value>The matrices.</value>
-        internal IDictionary<string, Matrix<TDataType>> Matrices
+        internal Matrix<TDataType> ReadMatrix<TDataType>(string name) where TDataType : struct, IEquatable<TDataType>, IFormattable
         {
-            get { return _matrices; }
+            return Parser<TDataType>.ReadMatrix(_matrices[name]);
         }
     }
 }

src/Data/Matlab/MatlabReader.cs

@@ -51,15 +51,15 @@ namespace MathNet.Numerics.Data.Matlab
 
             if (string.IsNullOrEmpty(matrixName))
             {
-                return file.FirstMatrix;
+                return file.ReadMatrix<TDataType>(file.FirstMatrixName);
             }
 
-            if (!file.Matrices.ContainsKey(matrixName))
+            if (!file.MatrixNames.Contains(matrixName))
             {
                 throw new KeyNotFoundException("Matrix with the provided name was not found.");
             }
 
-            return file.Matrices[matrixName];
+            return file.ReadMatrix<TDataType>(matrixName);
         }
 
         /// <typeparam name="TDataType">The data type of the Matrix. It can be either: double, float, Complex, or Complex32.</typeparam>
@@ -78,7 +78,7 @@ namespace MathNet.Numerics.Data.Matlab
         {
             var parser = new Parser<TDataType>(stream, matrixNames);
             var file = parser.Parse();
-            return file.Matrices.ToDictionary(matrix => matrix.Key, matrix => matrix.Value);
+            return file.MatrixNames.ToDictionary(name => name, file.ReadMatrix<TDataType>);
         }
 
         /// <typeparam name="TDataType">The data type of the Matrix. It can be either: double, float, Complex, or Complex32.</typeparam>

src/Data/Matlab/Parser.cs

@@ -136,9 +136,9 @@ namespace MathNet.Numerics.Data.Matlab
         /// Parses the file.
         /// </summary>
         /// <returns>The parsed MATLAB file as a <see cref="MatlabFile{TDataType}"/> object.</returns>
-        internal MatlabFile<TDataType> Parse()
+        internal MatlabFile Parse()
         {
-            var file = new MatlabFile<TDataType>();
+            var file = new MatlabFile();
 
             using (var reader = new BinaryReader(_stream))
             {
@@ -245,10 +245,43 @@ namespace MathNet.Numerics.Data.Matlab
         /// </summary>
         /// <param name="data">The data of the matrix.</param>
         /// <param name="file">The <see cref="MatlabFile{TDataType}"/> instance.</param>
-        void AddMatrix(byte[] data, MatlabFile<TDataType> file)
+        void AddMatrix(byte[] data, MatlabFile file)
         {
             using (var ms = new MemoryStream(data))
             using (var reader = new BinaryReader(ms))
+            {
+                // skip unneeded bytes
+                reader.BaseStream.Seek(20, SeekOrigin.Current);
+
+                var numDimensions = reader.ReadInt32()/8;
+                if (numDimensions > 2)
+                {
+                    throw new NotSupportedException(Resources.MoreThan2D);
+                }
+
+                // skip unneeded bytes
+                reader.BaseStream.Seek(10, SeekOrigin.Current);
+
+                int size = reader.ReadInt16();
+                if (size == 0)
+                {
+                    size = reader.ReadInt32();
+                }
+
+                var name = Encoding.ASCII.GetString(reader.ReadBytes(size));
+
+                // only grab wanted objects
+                if (_names.Count == 0 || _names.Contains(name))
+                {
+                    file.Add(name, data);
+                }
+            }
+        }
+
+        internal static Matrix<TDataType> ReadMatrix(byte[] data)
+        {
+            using (var stream = new MemoryStream(data))
+            using (var reader = new BinaryReader(stream))
             {
                 // skip tag - doesn't tell us anything we don't already know
                 reader.BaseStream.Seek(8, SeekOrigin.Current);
@@ -282,12 +315,6 @@ namespace MathNet.Numerics.Data.Matlab
                 var name = Encoding.ASCII.GetString(reader.ReadBytes(size));
                 AlignData(reader.BaseStream, size, smallBlock);
 
-                // only grab wanted objects
-                if (_names.Count != 0 && !_names.Contains(name))
-                {
-                    return;
-                }
-
                 var type = (DataType)reader.ReadInt16();
                 size = reader.ReadInt16();
                 if (size == 0)
@@ -313,11 +340,7 @@ namespace MathNet.Numerics.Data.Matlab
                         break;
                 }
 
-                file.Matrices.Add(name, matrix);
-                if (file.FirstMatrixName == null)
-                {
-                    file.FirstMatrixName = name;
-                }
+                return matrix;
             }
         }
     }