mysql-5.6.51/sql/sql_array.h

#ifndef SQL_ARRAY_INCLUDED
#define SQL_ARRAY_INCLUDED

/* Copyright (c) 2005, 2012, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.

   This program is also distributed with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have included with MySQL.

   This program 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 General Public License, version 2.0, for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA */

#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; }

  bool operator==(const Bounds_checked_array<Element_type>&rhs) const
  {
    return m_array == rhs.m_array && m_size == rhs.m_size;
  }
  bool operator!=(const Bounds_checked_array<Element_type>&rhs) const
  {
    return m_array != rhs.m_array || m_size != rhs.m_size;
  }

private:
  Element_type *m_array;
  size_t        m_size;
};

/*
  A typesafe wrapper around DYNAMIC_ARRAY
*/

template <class Elem> class Dynamic_array
{
  DYNAMIC_ARRAY  array;
public:
  Dynamic_array(uint prealloc=16, uint increment=16)
  {
    init(prealloc, increment);
  }

  void init(uint prealloc=16, uint increment=16)
  {
    my_init_dynamic_array(&array, sizeof(Elem), prealloc, increment);
  }

  /**
     @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(int idx)
  {
    return *(((Elem*)array.buffer) + idx);
  }
  /// Const variant of at(), which cannot change data
  const Elem& at(int idx) const
  {
    return *(((Elem*)array.buffer) + idx);
  }

  /// @returns pointer to first element; undefined behaviour if array is empty
  Elem *front()
  {
    DBUG_ASSERT(array.elements >= 1);
    return (Elem*)array.buffer;
  }

  /// @returns pointer to first element; undefined behaviour if array is empty
  const Elem *front() const
  {
    DBUG_ASSERT(array.elements >= 1);
    return (const Elem*)array.buffer;
  }

  /// @returns pointer to last element; undefined behaviour if array is empty.
  Elem *back()
  {
    DBUG_ASSERT(array.elements >= 1);
    return ((Elem*)array.buffer) + (array.elements - 1);
  }

  /// @returns pointer to last element; undefined behaviour if array is empty.
  const Elem *back() const
  {
    DBUG_ASSERT(array.elements >= 1);
    return ((const Elem*)array.buffer) + (array.elements - 1);
  }

  /**
     @retval false ok
     @retval true  OOM, @c my_error() has been called.
  */
  bool append(const Elem &el)
  {
    return insert_dynamic(&array, &el);
  }

  /// Pops the last element. Does nothing if array is empty.
  Elem& pop()
  {
    return *((Elem*)pop_dynamic(&array));
  }

  void del(uint idx)
  {
    delete_dynamic_element(&array, idx);
  }

  int elements() const
  {
    return array.elements;
  }

  void elements(uint num_elements)
  {
    DBUG_ASSERT(num_elements <= array.max_element);
    array.elements= num_elements;
  }

  void clear()
  {
    elements(0);
  }

  void set(uint idx, const Elem &el)
  {
    set_dynamic(&array, &el, idx);
  }

  ~Dynamic_array()
  {
    delete_dynamic(&array);
  }

  typedef int (*CMP_FUNC)(const Elem *el1, const Elem *el2);

  void sort(CMP_FUNC cmp_func)
  {
    my_qsort(array.buffer, array.elements, sizeof(Elem), (qsort_cmp)cmp_func);
  }
};

#endif /* SQL_ARRAY_INCLUDED */