1 files changed, 157 insertions, 51 deletions

diff --git a/sql/sql_array.h b/sql/sql_array.h
index e33e8932b42..d7eeaf7652d 100644
--- a/sql/sql_array.h
+++ b/sql/sql_array.h
@@ -19,8 +19,81 @@
 
 #include <my_sys.h>
 
+/**
+   A wrapper class which provides array bounds checking.
+   We do *not* own the array, we simply have a pointer to the first element,
+   and a length.
+
+   @remark
+   We want the compiler-generated versions of:
+   - the copy CTOR (memberwise initialization)
+   - the assignment operator (memberwise assignment)
+
+   @param Element_type The type of the elements of the container.
+ */
+template <typename Element_type> class Bounds_checked_array
+{
+public:
+  Bounds_checked_array() : m_array(NULL), m_size(0) {}
+
+  Bounds_checked_array(Element_type *el, size_t size)
+    : m_array(el), m_size(size)
+  {}
+
+  void reset() { m_array= NULL; m_size= 0; }
+ 
+  void reset(Element_type *array, size_t size)
+  {
+    m_array= array;
+    m_size= size;
+  }
+
+  /**
+    Set a new bound on the array. Does not resize the underlying
+    array, so the new size must be smaller than or equal to the
+    current size.
+   */
+  void resize(size_t new_size)
+  {
+    DBUG_ASSERT(new_size <= m_size);
+    m_size= new_size;
+  }
+
+  Element_type &operator[](size_t n)
+  {
+    DBUG_ASSERT(n < m_size);
+    return m_array[n];
+  }
+
+  const Element_type &operator[](size_t n) const
+  {
+    DBUG_ASSERT(n < m_size);
+    return m_array[n];
+  }
+
+  size_t element_size() const { return sizeof(Element_type); }
+  size_t size() const         { return m_size; }
+
+  bool is_null() const { return m_array == NULL; }
+
+  void pop_front()
+  {
+    DBUG_ASSERT(m_size > 0);
+    m_array+= 1;
+    m_size-= 1;
+  }
+
+  Element_type *array() const { return m_array; }
+
+private:
+  Element_type *m_array;
+  size_t        m_size;
+};
+
 /*
   A typesafe wrapper around DYNAMIC_ARRAY
+
+  TODO: Change creator to take a THREAD_SPECIFIC option.
 */
 
 template <class Elem> class Dynamic_array
@@ -29,114 +102,147 @@ template <class Elem> class Dynamic_array
 public:
   Dynamic_array(uint prealloc=16, uint increment=16)
   {
-    my_init_dynamic_array(&array, sizeof(Elem), prealloc, increment);
+    init(prealloc, increment);
+  }
+
+  void init(uint prealloc=16, uint increment=16)
+  {
+    init_dynamic_array2(&array, sizeof(Elem), 0, prealloc, increment, MYF(0));
   }
 
-  Elem& at(int idx)
+  /**
+     @note Though formally this could be declared "const" it would be
+     misleading at it returns a non-const pointer to array's data.
+  */
+  Elem& at(size_t idx)
+  {
+    DBUG_ASSERT(idx < array.elements);
+    return *(((Elem*)array.buffer) + idx);
+  }
+  /// Const variant of at(), which cannot change data
+  const Elem& at(size_t idx) const
   {
     return *(((Elem*)array.buffer) + idx);
   }
 
+  /// @returns pointer to first element
   Elem *front()
   {
     return (Elem*)array.buffer;
   }
 
+  /// @returns pointer to first element
+  const Elem *front() const
+  {
+    return (const Elem*)array.buffer;
+  }
+
+  /// @returns pointer to last element
   Elem *back()
   {
-    return ((Elem*)array.buffer) + array.elements;
+    return ((Elem*)array.buffer) + array.elements - 1;
   }
 
-  bool append(Elem &el)
+  /// @returns pointer to last element
+  const Elem *back() const
   {
-    return (insert_dynamic(&array, (uchar*)&el));
+    return ((const Elem*)array.buffer) + array.elements - 1;
   }
 
-  int elements()
+  /**
+     @retval false ok
+     @retval true  OOM, @c my_error() has been called.
+  */
+  bool append(const Elem &el)
   {
-    return array.elements;
+    return insert_dynamic(&array, &el);
   }
 
-  ~Dynamic_array()
+  bool append_val(Elem el)
   {
-    delete_dynamic(&array);
+    return (insert_dynamic(&array, (uchar*)&el));
   }
 
-  typedef int (*CMP_FUNC)(const Elem *el1, const Elem *el2);
+  bool push(Elem &el)
+  {
+    return append(el);
+  }
 
-  void sort(CMP_FUNC cmp_func)
+  /// Pops the last element. Does nothing if array is empty.
+  Elem& pop()
   {
-    my_qsort(array.buffer, array.elements, sizeof(Elem), (qsort_cmp)cmp_func);
+    return *((Elem*)pop_dynamic(&array));
   }
-};
 
-/* 
-  Array of pointers to Elem that uses memory from MEM_ROOT
+  void del(uint idx)
+  {
+    delete_dynamic_element(&array, idx);
+  }
 
-  MEM_ROOT has no realloc() so this is supposed to be used for cases when
-  reallocations are rare.
-*/
+  size_t elements() const
+  {
+    return array.elements;
+  }
 
-template <class Elem> class Array
-{
-  enum {alloc_increment = 16};
-  Elem **buffer;
-  uint n_elements, max_element;
-public:
-  Array(MEM_ROOT *mem_root, uint prealloc=16)
+  void elements(size_t num_elements)
   {
-    buffer= (Elem**)alloc_root(mem_root, prealloc * sizeof(Elem**));
-    max_element = buffer? prealloc : 0;
-    n_elements= 0;
+    DBUG_ASSERT(num_elements <= array.max_element);
+    array.elements= num_elements;
   }
 
-  Elem& at(int idx)
+  void clear()
   {
-    return *(((Elem*)buffer) + idx);
+    elements(0);
   }
 
-  Elem **front()
+  void set(uint idx, const Elem &el)
   {
-    return buffer;
+    set_dynamic(&array, &el, idx);
   }
 
-  Elem **back()
+  void freeze()
   {
-    return buffer + n_elements;
+    freeze_size(&array);
   }
 
-  bool append(MEM_ROOT *mem_root, Elem *el)
+  bool resize(size_t new_size, Elem default_val)
   {
-    if (n_elements == max_element)
+    size_t old_size= elements();
+    if (allocate_dynamic(&array, new_size))
+      return true;
+    
+    if (new_size > old_size)
     {
-      Elem **newbuf;
-      if (!(newbuf= (Elem**)alloc_root(mem_root, (n_elements + alloc_increment)*
-                                                  sizeof(Elem**))))
+      set_dynamic(&array, (uchar*)&default_val, new_size - 1);
+      /*for (size_t i= old_size; i != new_size; i++)
       {
-        return FALSE;
-      }
-      memcpy(newbuf, buffer, n_elements*sizeof(Elem*));
-      buffer= newbuf;
+        at(i)= default_val;
+      }*/
     }
-    buffer[n_elements++]= el;
-    return FALSE;
+    return false;
   }
 
-  int elements()
+  ~Dynamic_array()
   {
-    return n_elements;
+    delete_dynamic(&array);
   }
 
-  void clear()
+  void free_memory()
   {
-    n_elements= 0;
+    delete_dynamic(&array);
   }
 
-  typedef int (*CMP_FUNC)(Elem * const *el1, Elem *const *el2);
+  typedef int (*CMP_FUNC)(const Elem *el1, const Elem *el2);
 
   void sort(CMP_FUNC cmp_func)
   {
-    my_qsort(buffer, n_elements, sizeof(Elem*), (qsort_cmp)cmp_func);
+    my_qsort(array.buffer, array.elements, sizeof(Elem), (qsort_cmp)cmp_func);
+  }
+
+  typedef int (*CMP_FUNC2)(void *, const Elem *el1, const Elem *el2);
+  void sort(CMP_FUNC2 cmp_func, void *data)
+  {
+    my_qsort2(array.buffer, array.elements, sizeof(Elem), (qsort2_cmp)cmp_func, data);
   }
 };