Sparse module:

* add a MappedSparseMatrix class (like Eigen::Map but for sparse
  matrices)
* rename SparseArray to CompressedStorage

Eigen/src/Sparse/CompressedStorage.h

@@ -0,0 +1,144 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra. Eigen itself is part of the KDE project.
+//
+// Copyright (C) 2008 Gael Guennebaud <g.gael@free.fr>
+//
+// Eigen is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 3 of the License, or (at your option) any later version.
+//
+// Alternatively, you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of
+// the License, or (at your option) any later version.
+//
+// Eigen is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+// FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License or the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License and a copy of the GNU General Public License along with
+// Eigen. If not, see <http://www.gnu.org/licenses/>.
+
+#ifndef EIGEN_COMPRESSED_STORAGE_H
+#define EIGEN_COMPRESSED_STORAGE_H
+
+/** Stores a sparse set of values as a list of values and a list of indices.
+  *
+  */
+template<typename Scalar>
+class CompressedStorage
+{
+  public:
+    CompressedStorage()
+      : m_values(0), m_indices(0), m_size(0), m_allocatedSize(0)
+    {}
+
+    CompressedStorage(int size)
+      : m_values(0), m_indices(0), m_size(0), m_allocatedSize(0)
+    {
+      resize(size);
+    }
+
+    CompressedStorage(const CompressedStorage& other)
+    {
+      *this = other;
+    }
+
+    CompressedStorage& operator=(const CompressedStorage& other)
+    {
+      resize(other.size());
+      memcpy(m_values, other.m_values, m_size * sizeof(Scalar));
+      memcpy(m_indices, other.m_indices, m_size * sizeof(int));
+      return *this;
+    }
+
+    void swap(CompressedStorage& other)
+    {
+      std::swap(m_values, other.m_values);
+      std::swap(m_indices, other.m_indices);
+      std::swap(m_size, other.m_size);
+      std::swap(m_allocatedSize, other.m_allocatedSize);
+    }
+
+    ~CompressedStorage()
+    {
+      delete[] m_values;
+      delete[] m_indices;
+    }
+
+    void reserve(int size)
+    {
+      int newAllocatedSize = m_size + size;
+      if (newAllocatedSize > m_allocatedSize)
+        reallocate(newAllocatedSize);
+    }
+
+    void squeeze()
+    {
+      if (m_allocatedSize>m_size)
+        reallocate(m_size);
+    }
+
+    void resize(int size, int reserveSizeFactor = 0)
+    {
+      if (m_allocatedSize<size)
+        reallocate(size + reserveSizeFactor*size);
+      m_size = size;
+    }
+
+    void append(const Scalar& v, int i)
+    {
+      int id = m_size;
+      resize(m_size+1, 1);
+      m_values[id] = v;
+      m_indices[id] = i;
+    }
+
+    int size() const { return m_size; }
+    void clear() { m_size = 0; }
+
+    Scalar& value(int i) { return m_values[i]; }
+    const Scalar& value(int i) const { return m_values[i]; }
+
+    int& index(int i) { return m_indices[i]; }
+    const int& index(int i) const { return m_indices[i]; }
+
+    static CompressedStorage Map(int* indices, Scalar* values, int size)
+    {
+      CompressedStorage res;
+      res.m_indices = indices;
+      res.m_values = values;
+      res.m_allocatedSize = res.m_size = size;
+      return res;
+    }
+
+  protected:
+
+    void reallocate(int size)
+    {
+      Scalar* newValues  = new Scalar[size];
+      int* newIndices = new int[size];
+      int copySize = std::min(size, m_size);
+      // copy
+      memcpy(newValues,  m_values,  copySize * sizeof(Scalar));
+      memcpy(newIndices, m_indices, copySize * sizeof(int));
+      // delete old stuff
+      delete[] m_values;
+      delete[] m_indices;
+      m_values = newValues;
+      m_indices = newIndices;
+      m_allocatedSize = size;
+    }
+
+  protected:
+    Scalar* m_values;
+    int* m_indices;
+    int m_size;
+    int m_allocatedSize;
+
+};
+
+#endif // EIGEN_COMPRESSED_STORAGE_H