Long story short, I needed a way to read and write the MAT files that MATLAB generates and loads with the ‘load’ and ’save’ commands. Using the C API directly seemed cumbersome and error prone, so this C++ wrapper was born.

Download it (4 kB) as .tar.bz2 or as zip.

A basic use case looks like this (also check out test.cc):

#include "matlabfile.h"
using namespace MatlabUtilities;
 
File matfile("some.mat");
std::vector<double> vec1;
matfile.read<Types::real_vector>("v1", vec1);
 
double[100] vec2;
matfile.read<Types::fixed_length_real_vector<100> >("v2", vec2);
 
matfile.write<Types::string>("hw", "Hello World!");


Not all MATLAB types are implemented (check Types namespace in matlabaccessors.h for a list), in particular real matrices with a column and row length different from one are missing for two reasons: I didn’t need them for the job and you probably have your own preferred matrix type anyway. But don’t worry, the template-design makes it easy to add these missing features. What needs to be implemented is

struct real_matrix {};
 
template <>
struct Reader<real_matrix, MyMatrix> {
    static void read(mxArray* var, MyMatrix& result);
}
 
template <>
struct Writer<real_matrix, MyMatrix> {
    static mxArray* write(MyMatrix& source);
}
 
template <>
struct TypeCheck<real_matrix> {
    static bool typeCheck(mxArray* var);
}


where the ‘read’ function reads data from the mxArray into result, ‘write’ returns a new mxArray filled with source’s data and ‘typeCheck’ returns true if the mxArray contains a real_matrix. With these template specializations in place you can use the new code like this:

MyMatrix mat;
matfile.read<real_matrix>("somevarname", mat);
matfile.write<real_matrix>("someother", mat);

Similarly, you can add a new reader to say ‘real_vector’ to accomodate for your own vector type.

The code snippet only contains code for reading and writing data. Other management functionality, like listing all fields in a MAT file is not implemented. I hope it will nevertheless be useful for someone.