mathnet-numerics/src/Numerics/LinearAlgebra/IO/MatlabReader.cs

// <copyright file="MatlabReader.cs" company="Math.NET">
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// http://numerics.mathdotnet.com
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// http://mathnetnumerics.codeplex.com
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namespace MathNet.Numerics.LinearAlgebra.IO
{
    using System;
    using System.Collections.Generic;
    using System.IO;
    using System.Linq;
    using Generic;
    using Matlab;
    using Properties;

    /// <summary>
    /// Creates matrices from Matlab files.
    /// </summary>
    /// <typeparam name="TDataType">The data type of the Matrix. It can be either: double, float, Complex, or Complex32.</typeparam>
    public class MatlabMatrixReader<TDataType> where TDataType : struct, IEquatable<TDataType>, IFormattable
    {
        /// <summary>
        /// The name of the file to read from.
        /// </summary>
        private readonly string _filename;

        /// <summary>
        /// The stream to read from if we are not reading from a file directly.
        /// </summary>
        private readonly Stream _stream;

        /// <summary>
        /// Initializes a new instance of the <see cref="MatlabMatrixReader{TDataType}"/> class.
        /// </summary>
        /// <param name="filename">Name of the file to read matrices from.</param>
        public MatlabMatrixReader(string filename)
        {
            if (string.IsNullOrEmpty(filename))
            {
                throw new ArgumentException(Resources.StringNullOrEmpty, "filename");
            }

            if (!File.Exists(filename))
            {
                throw new FileNotFoundException(Resources.FileDoesNotExist, "filename");
            }

            _filename = filename;
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="MatlabMatrixReader{TDataType}"/> class.
        /// </summary>
        /// <param name="stream">The stream to reader matrices from.</param>
        public MatlabMatrixReader(Stream stream)
        {
            if (stream == null)
            {
                throw new ArgumentNullException("stream");
            }

            _stream = stream;
        }

        /// <summary>
        /// Reads the first matrix from the file or stream.
        /// </summary>
        /// <returns>
        /// A sparse or dense matrix depending on how the matrix
        /// is defined in the Matlab file.
        /// </returns>
        public Matrix<TDataType> ReadMatrix()
        {
            return ReadMatrix(null);
        }

        /// <summary>
        /// Reads the named matrix from the file or stream.
        /// </summary>
        /// <param name="matrixName">The name of the matrix to read.</param>
        /// <returns>
        /// A sparse or dense matrix depending on how the matrix
        /// is defined in the Matlab file.
        /// <see langword="null"/> is returned if a matrix with the requests name doesn't exist.
        /// </returns>
        public Matrix<TDataType> ReadMatrix(string matrixName)
        {
            Stream stream;
            if (_filename == null)
            {
                stream = _stream;
                _stream.Seek(0, SeekOrigin.Begin);
            }
            else
            {
                stream = new FileStream(_filename, FileMode.Open, FileAccess.Read);
            }

            var names = string.IsNullOrEmpty(matrixName) ? new string[] { } : new[] { matrixName };
            var parser = new MatlabParser<TDataType>(stream, names);
            var file = parser.Parse();

            Matrix<TDataType> matrix = null;
            if (string.IsNullOrEmpty(matrixName))
            {
                matrix = file.FirstMatrix;
            }
            else if (file.Matrices.ContainsKey(matrixName))
            {
                matrix = file.Matrices[matrixName];
            }

            if (_filename != null)
            {
                stream.Close();
                stream.Dispose();
            }

            return matrix;
        }

        /// <summary>
        /// Reads all matrices from the file or stream.
        /// </summary>
        /// <returns>All matrices from the file or stream. The key to the <see cref="IDictionary{T,K}"/> 
        /// is the matrix's name.</returns>
        public IDictionary<string, Matrix<TDataType>> ReadMatrices()
        {
            return ReadMatrices(new string[] { });
        }

        /// <summary>
        /// Reads the named matrices from the file or stream.
        /// </summary>
        /// <param name="names">The names of the matrices to retrieve.</param>
        /// <returns>
        /// The named matrices from the file or stream. The key to the <see cref="IDictionary{T,K}"/> 
        /// is the matrix's name.</returns>
        public IDictionary<string, Matrix<TDataType>> ReadMatrices(IEnumerable<string> names)
        {
            Stream stream;
            if (_filename == null)
            {
                stream = _stream;
                _stream.Seek(0, SeekOrigin.Begin);
            }
            else
            {
                stream = new BufferedStream(new FileStream(_filename, FileMode.Open, FileAccess.Read));
            }

            var parser = new MatlabParser<TDataType>(stream, names);
            var file = parser.Parse();

            if (_filename != null)
            {
                stream.Close();
                stream.Dispose();
            }

            return file.Matrices.ToDictionary(matrix => matrix.Key, matrix => matrix.Value);
        }
    }
}