Allow Array's of non-POD types through specialized Array_Element class.

1 files changed, 194 insertions, 18 deletions

diff --git a/libdimensionxx/dimensionxx/array.hpp b/libdimensionxx/dimensionxx/array.hpp
index 84bc06b..aa1f805 100644
--- a/libdimensionxx/dimensionxx/array.hpp
+++ b/libdimensionxx/dimensionxx/array.hpp
@@ -25,9 +25,38 @@
 
 #include <tr1/memory> // For tr1::shared_ptr
 #include <cstdlib>    // For size_t
+#include <vector>
 
 namespace Dimension
 {
+  // Class to store POD types, and wrapped dmnsn_* types, including polymorphic
+  // types.  The non-specialized version will only handle POD types; specialize
+  // it to allow storage of classes in Array's.
+  template <typename T>
+  class Array_Element
+  {
+  public:
+    typedef T C_Type;
+
+    inline Array_Element();
+    inline Array_Element(T t);
+
+    // Specializations should implement this constructor if C_Type differs from
+    // T - but it should throw if T is a polymorphic type
+    // Array_Element(C_Type c);
+
+    // Array_Element(const Array_Element& ae);
+    // ~Array_Element();
+
+    // Array_Element& operator=(const Array_Element& ae);
+
+    C_Type dmnsn() const { return m_t; }
+    T& object(C_Type* c) const { return *c; }
+
+  private:
+    T m_t;
+  };
+
   // Array template class, wraps a dmnsn_array*.  Copying is possible, but
   // copies refer to the same object, which is reference counted.  T must be
   // a POD type.
@@ -35,32 +64,95 @@ namespace Dimension
   class Array
   {
   public:
-    Array();
-    explicit Array(dmnsn_array* array);
+    inline Array();
+    explicit inline Array(dmnsn_array* array);
     // Array(const Array& a);
     ~Array()
-    { if (m_array && m_array.unique()) { dmnsn_delete_array(dmnsn()); } }
+      { if (m_array && m_array.unique()) { dmnsn_delete_array(dmnsn()); } }
 
     // Array& operator=(const Array& a);
 
-    T& operator[](std::size_t i)
-    { return *reinterpret_cast<T*>(dmnsn_array_at(dmnsn(), i)); }
-    const T& operator[](std::size_t i) const
-    { return *reinterpret_cast<const T*>(dmnsn_array_at(dmnsn(), i)); }
+    inline T&       operator[](std::size_t i);
+    inline const T& operator[](std::size_t i) const;
 
     std::size_t size() const { return dmnsn_array_size(dmnsn()); }
-    void resize(std::size_t size) { dmnsn_array_resize(dmnsn(), size); }
+    inline void resize(std::size_t size);
+
+    inline void push(T& object);
+    inline void push(const T& object); // Not valid for polymorphic types
+    inline void pop();
 
     // Access the wrapped C object.
-    dmnsn_array*       dmnsn();
-    const dmnsn_array* dmnsn() const;
+    inline dmnsn_array*       dmnsn();
+    inline const dmnsn_array* dmnsn() const;
 
     // Release ownership of the dmnsn_array*, needed for returning a
     // dmnsn_array* from a function.
-    dmnsn_array* release();
+    inline dmnsn_array* release();
 
   private:
+    typedef typename Array_Element<T>::C_Type C_Type;
+
     std::tr1::shared_ptr<dmnsn_array*> m_array;
+    std::vector<Array_Element<T> > m_elements;
+  };
+
+  // Base class for non-polymorphic wrappers
+  template <typename T, typename C>
+  class DMNSN_Array_Element
+  {
+  public:
+    typedef C C_Type;
+
+    DMNSN_Array_Element() {
+      throw Dimension_Error("Couldn't default-construct an array element.");
+    }
+
+    DMNSN_Array_Element(const T& object) : m_object(new T(object)) { }
+    DMNSN_Array_Element(C_Type c) : m_object(new T(c)) { }
+    // DMNSN_Array_Element(const DMNSN_Array_Element& ae);
+    // ~DMNSN_Array_Element();
+
+    // DMNSN_Array_Element& operator=(const DMNSN_Array_Element& ae);
+
+    C_Type dmnsn() const { return m_object->dmnsn(); }
+    T& object(C_Type* c) const { return *m_object; }
+
+  private:
+    std::tr1::shared_ptr<T> m_object;
+  };
+
+  // Base class for polymorphic wrappers
+  template <typename T, typename C>
+  class Polymorphic_Array_Element
+  {
+  public:
+    typedef C C_Type;
+
+    Polymorphic_Array_Element()
+    {
+      throw Dimension_Error("Cannot default-construct a polymorphic array"
+                            " object.");
+    }
+
+    Polymorphic_Array_Element(T& object) : m_object(object.copy()) { }
+
+    Polymorphic_Array_Element(C_Type c)
+    {
+      throw Dimension_Error("Cannot wrap existing dmnsn_array* elements in"
+                            " polymorphic class.");
+    }
+
+    // Polymorphic_Array_Element(const Polymorphic_Array_Element& ae);
+    // ~Polymorphic_Array_Element();
+
+    // Polymorphic_Array_Element& operator=(const Polymorphic_Array_Element& e);
+
+    C_Type dmnsn() const { return m_object->dmnsn(); }
+    T& object(C_Type* c) const { return *m_object; }
+
+  private:
+    std::tr1::shared_ptr<T> m_object;
   };
 
   // A constraint enforcing that T is a POD type by making it part of a union.
@@ -77,26 +169,110 @@ namespace Dimension
     static_cast<void>(constraint); // Silence unused variable warning
   }
 
+  // Array_Element
+
   template <typename T>
-  Array<T>::Array()
-    : m_array(new dmnsn_array*(dmnsn_new_array(sizeof(T))))
+  inline
+  Array_Element<T>::Array_Element()
   {
     void (*constraint)() = &POD_constraint<T>;
     static_cast<void>(constraint); // Silence unused variable warning
   }
 
   template <typename T>
-  Array<T>::Array(dmnsn_array* array)
-    : m_array(new dmnsn_array*(array))
+  inline
+  Array_Element<T>::Array_Element(T t)
+    : m_t(t)
   {
     void (*constraint)() = &POD_constraint<T>;
     static_cast<void>(constraint); // Silence unused variable warning
   }
 
+  // Array constructors
+
+  template <typename T>
+  inline
+  Array<T>::Array()
+    : m_array(new dmnsn_array*(dmnsn_new_array(sizeof(T)))) { }
+
+  template <typename T>
+  inline
+  Array<T>::Array(dmnsn_array* array)
+    : m_array(new dmnsn_array*(array))
+  {
+    m_elements.reserve(dmnsn_array_size(dmnsn()));
+    for (std::size_t i = 0; i < dmnsn_array_size(dmnsn()); ++i) {
+      C_Type* c = reinterpret_cast<C_Type*>(dmnsn_array_at(dmnsn(), i));
+      m_elements.push_back(Array_Element<T>(*c));
+    }
+  }
+
+  // Array element access
+
+  template <typename T>
+  inline T&
+  Array<T>::operator[](std::size_t i)
+  {
+    if (i >= m_elements.size()) {
+      m_elements.resize(i + 1);
+    }
+    C_Type* c = reinterpret_cast<C_Type*>(dmnsn_array_at(dmnsn(), i));
+    return m_elements[i].object(c);
+  }
+
+  template <typename T>
+  inline const T&
+  Array<T>::operator[](std::size_t i) const
+  {
+    if (i >= m_elements.size()) {
+      m_elements.resize(i + 1);
+    }
+    C_Type* c = reinterpret_cast<C_Type*>(dmnsn_array_at(dmnsn(), i));
+    return m_elements[i].object(c);
+  }
+
+  template <typename T>
+  inline void
+  Array<T>::resize(std::size_t size)
+  {
+    m_elements.resize(size);
+    dmnsn_array_resize(dmnsn(), size);
+  }
+
+  template <typename T>
+  inline void
+  Array<T>::push(T& object)
+  {
+    Array_Element<T> ae(object);
+    m_elements.push_back(ae);
+
+    C_Type c = ae.dmnsn();
+    dmnsn_array_push(dmnsn(), &c);
+  }
+
+  template <typename T>
+  inline void
+  Array<T>::push(const T& object)
+  {
+    Array_Element<T> ae(object);
+    m_elements.push_back(ae);
+
+    C_Type c = ae.dmnsn();
+    dmnsn_array_push(dmnsn(), &c);
+  }
+
+  template <typename T>
+  inline void
+  Array<T>::pop()
+  {
+    m_elements.pop();
+    dmnsn_array_resize(dmnsn_array_size(dmnsn()) - 1);
+  }
+
   // Access the underlying dmnsn_array*
 
   template <typename T>
-  dmnsn_array*
+  inline dmnsn_array*
   Array<T>::dmnsn()
   {
     if (!m_array) {
@@ -107,7 +283,7 @@ namespace Dimension
   }
 
   template <typename T>
-  const dmnsn_array*
+  inline const dmnsn_array*
   Array<T>::dmnsn() const
   {
     if (!m_array) {
@@ -119,7 +295,7 @@ namespace Dimension
 
   // Release the dmnsn_array*, if we are the only Array holding it
   template <typename T>
-  dmnsn_array*
+  inline dmnsn_array*
   Array<T>::release()
   {
     dmnsn_array* array = dmnsn();