mariadb/sql/sql_list.h

/* Copyright (C) 2000-2003 MySQL AB

   This program is free software; 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.

   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 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, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */


#ifdef USE_PRAGMA_INTERFACE
#pragma interface			/* gcc class implementation */
#endif

/* mysql standard class memory allocator */

class Sql_alloc
{
public:
  static void *operator new(size_t size)
  {
    return (void*) sql_alloc((uint) size);
  }
  static void *operator new[](size_t size)
  {
    return (void*) sql_alloc((uint) size);
  }
  static void *operator new(size_t size, MEM_ROOT *mem_root)
  { return (void*) alloc_root(mem_root, (uint) size); }
  static void operator delete(void *ptr, size_t size) { TRASH(ptr, size); }
  static void operator delete(void *ptr, MEM_ROOT *mem_root)
  { /* never called */ }
  static void operator delete[](void *ptr, size_t size) { TRASH(ptr, size); }
#ifdef HAVE_purify
  bool dummy;
  inline Sql_alloc() :dummy(0) {}
  inline ~Sql_alloc() {}
#else
  inline Sql_alloc() {}
  inline ~Sql_alloc() {}
#endif

};


/*
  Basic single linked list
  Used for item and item_buffs.
  All list ends with a pointer to the 'end_of_list' element, which
  data pointer is a null pointer and the next pointer points to itself.
  This makes it very fast to traverse lists as we don't have to
  test for a specialend condition for list that can't contain a null
  pointer.
*/

class list_node :public Sql_alloc
{
public:
  list_node *next;
  void *info;
  list_node(void *info_par,list_node *next_par)
    :next(next_par),info(info_par)
    {}
  list_node()					/* For end_of_list */
    {
      info=0;
      next= this;
    }
  friend class base_list;
  friend class base_list_iterator;
};


extern list_node end_of_list;

class base_list :public Sql_alloc
{
protected:
  list_node *first,**last;

public:
  uint elements;

  inline void empty() { elements=0; first= &end_of_list; last=&first;}
  inline base_list() { empty(); }
  inline base_list(const base_list &tmp) :Sql_alloc()
  {
    elements=tmp.elements;
    first=tmp.first;
    last=tmp.last;
  }
  inline base_list(bool error) { }
  inline bool push_back(void *info)
  {
    if (((*last)=new list_node(info, &end_of_list)))
    {
      last= &(*last)->next;
      elements++;
      return 0;
    }
    return 1;
  }
  inline bool push_back(void *info, MEM_ROOT *mem_root)
  {
    if (((*last)=new (mem_root) list_node(info, &end_of_list)))
    {
      last= &(*last)->next;
      elements++;
      return 0;
    }
    return 1;
  }
  inline bool push_front(void *info)
  {
    list_node *node=new list_node(info,first);
    if (node)
    {
      if (last == &first)
	last= &node->next;
      first=node;
      elements++;
      return 0;
    }
    return 1;
  }
  void remove(list_node **prev)
  {
    list_node *node=(*prev)->next;
    if (!--elements)
      last= &first;
    else if (last == &(*prev)->next)
      last= prev;
    delete *prev;
    *prev=node;
  }
  inline void concat(base_list *list)
  {
    if (!list->is_empty())
    {
      *last= list->first;
      last= list->last;
      elements+= list->elements;
    }
  }
  inline void *pop(void)
  {
    if (first == &end_of_list) return 0;
    list_node *tmp=first;
    first=first->next;
    if (!--elements)
      last= &first;
    return tmp->info;
  }
  inline void disjoin(base_list *list)
  {
    list_node **prev= &first;
    list_node *node= first;
    list_node *list_first= list->first;
    elements=0;
    while (node && node != list_first)
    {
      prev= &node->next;
      node= node->next;
      elements++;
    }
    *prev= *last;
    last= prev;
  }
  inline void prepand(base_list *list)
  {
    if (!list->is_empty())
    {
      *list->last= first;
      first= list->first;
      elements+= list->elements;
    }
  }
  inline list_node* last_node() { return *last; }
  inline list_node* first_node() { return first;}
  inline void *head() { return first->info; }
  inline void **head_ref() { return first != &end_of_list ? &first->info : 0; }
  inline bool is_empty() { return first == &end_of_list ; }
  inline list_node *last_ref() { return &end_of_list; }
  friend class base_list_iterator;
  friend class error_list;
  friend class error_list_iterator;

#ifdef LIST_EXTRA_DEBUG
  /*
    Check list invariants and print results into trace. Invariants are:
      - (*last) points to end_of_list
      - There are no NULLs in the list.
      - base_list::elements is the number of elements in the list.

    SYNOPSIS
      check_list()
        name  Name to print to trace file

    RETURN 
      1  The list is Ok.
      0  List invariants are not met.
  */

  bool check_list(const char *name)
  {
    base_list *list= this;
    list_node *node= first;
    uint cnt= 0;

    while (node->next != &end_of_list)
    {
      if (!node->info)
      {
        DBUG_PRINT("list_invariants",("%s: error: NULL element in the list", 
                                      name));
        return FALSE;
      }
      node= node->next;
      cnt++;
    }
    if (last != &(node->next))
    {
      DBUG_PRINT("list_invariants", ("%s: error: wrong last pointer", name));
      return FALSE;
    }
    if (cnt+1 != elements)
    {
      DBUG_PRINT("list_invariants", ("%s: error: wrong element count", name));
      return FALSE;
    }
    DBUG_PRINT("list_invariants", ("%s: list is ok", name));
    return TRUE;
  }
#endif // LIST_EXTRA_DEBUG

protected:
  void after(void *info,list_node *node)
  {
    list_node *new_node=new list_node(info,node->next);
    node->next=new_node;
    elements++;
    if (last == &(node->next))
      last= &new_node->next;
  }
};


class base_list_iterator
{
protected:
  base_list *list;
  list_node **el,**prev,*current;
  void sublist(base_list &ls, uint elm)
  {
    ls.first= *el;
    ls.last= list->last;
    ls.elements= elm;
  }
public:
  base_list_iterator(base_list &list_par) 
    :list(&list_par), el(&list_par.first), prev(0), current(0)
  {}

  inline void *next(void)
  {
    prev=el;
    current= *el;
    el= &current->next;
    return current->info;
  }
  inline void *next_fast(void)
  {
    list_node *tmp;
    tmp= *el;
    el= &tmp->next;
    return tmp->info;
  }
  inline void rewind(void)
  {
    el= &list->first;
  }
  inline void *replace(void *element)
  {						// Return old element
    void *tmp=current->info;
    DBUG_ASSERT(current->info != 0);
    current->info=element;
    return tmp;
  }
  void *replace(base_list &new_list)
  {
    void *ret_value=current->info;
    if (!new_list.is_empty())
    {
      *new_list.last=current->next;
      current->info=new_list.first->info;
      current->next=new_list.first->next;
      if ((list->last == &current->next) && (new_list.elements > 1))
	list->last= new_list.last;
      list->elements+=new_list.elements-1;
    }
    return ret_value;				// return old element
  }
  inline void remove(void)			// Remove current
  {
    list->remove(prev);
    el=prev;
    current=0;					// Safeguard
  }
  void after(void *element)			// Insert element after current
  {
    list->after(element,current);
    current=current->next;
    el= &current->next;
  }
  inline void **ref(void)			// Get reference pointer
  {
    return &current->info;
  }
  inline bool is_last(void)
  {
    return el == &list->last_ref()->next;
  }
  friend class error_list_iterator;
};

template <class T> class List :public base_list
{
public:
  inline List() :base_list() {}
  inline List(const List<T> &tmp) :base_list(tmp) {}
  inline bool push_back(T *a) { return base_list::push_back(a); }
  inline bool push_back(T *a, MEM_ROOT *mem_root)
  { return base_list::push_back(a, mem_root); }
  inline bool push_front(T *a) { return base_list::push_front(a); }
  inline T* head() {return (T*) base_list::head(); }
  inline T** head_ref() {return (T**) base_list::head_ref(); }
  inline T* pop()  {return (T*) base_list::pop(); }
  inline void concat(List<T> *list) { base_list::concat(list); }
  inline void disjoin(List<T> *list) { base_list::disjoin(list); }
  inline void prepand(List<T> *list) { base_list::prepand(list); }
  void delete_elements(void)
  {
    list_node *element,*next;
    for (element=first; element != &end_of_list; element=next)
    {
      next=element->next;
      delete (T*) element->info;
    }
    empty();
  }
};


template <class T> class List_iterator :public base_list_iterator
{
public:
  List_iterator(List<T> &a) : base_list_iterator(a) {}
  inline T* operator++(int) { return (T*) base_list_iterator::next(); }
  inline T *replace(T *a)   { return (T*) base_list_iterator::replace(a); }
  inline T *replace(List<T> &a) { return (T*) base_list_iterator::replace(a); }
  inline void rewind(void)  { base_list_iterator::rewind(); }
  inline void remove()      { base_list_iterator::remove(); }
  inline void after(T *a)   { base_list_iterator::after(a); }
  inline T** ref(void)	    { return (T**) base_list_iterator::ref(); }
};


template <class T> class List_iterator_fast :public base_list_iterator
{
protected:
  inline T *replace(T *a)   { return (T*) 0; }
  inline T *replace(List<T> &a) { return (T*) 0; }
  inline void remove(void)  { }
  inline void after(T *a)   { }
  inline T** ref(void)	    { return (T**) 0; }

public:
  inline List_iterator_fast(List<T> &a) : base_list_iterator(a) {}
  inline T* operator++(int) { return (T*) base_list_iterator::next_fast(); }
  inline void rewind(void)  { base_list_iterator::rewind(); }
  void sublist(List<T> &list_arg, uint el_arg)
  {
    base_list_iterator::sublist(list_arg, el_arg);
  }
};


/*
  A simple intrusive list which automaticly removes element from list
  on delete (for THD element)
*/

struct ilink
{
  struct ilink **prev,*next;
  static void *operator new(size_t size)
  {
    return (void*)my_malloc((uint)size, MYF(MY_WME | MY_FAE));
  }
  static void operator delete(void* ptr_arg, size_t size)
  {
     my_free((gptr)ptr_arg, MYF(MY_WME|MY_ALLOW_ZERO_PTR));
  }

  inline ilink()
  {
    prev=0; next=0;
  }
  inline void unlink()
  {
    /* Extra tests because element doesn't have to be linked */
    if (prev) *prev= next;
    if (next) next->prev=prev;
    prev=0 ; next=0;
  }
  virtual ~ilink() { unlink(); }		/*lint -e1740 */
};


template <class T> class I_List_iterator;

/*
  WARNING: copy constructor of this class does not create a usable
  copy, as its members may point at each other.
*/

class base_ilist
{
public:
  struct ilink *first,last;
  inline void empty() { first= &last; last.prev= &first; }
  base_ilist() { empty(); }
  inline bool is_empty() {  return first == &last; }
  inline void append(ilink *a)
  {
    first->prev= &a->next;
    a->next=first; a->prev= &first; first=a;
  }
  inline void push_back(ilink *a)
  {
    *last.prev= a;
    a->next= &last;
    a->prev= last.prev;
    last.prev= &a->next;
  }
  inline struct ilink *get()
  {
    struct ilink *first_link=first;
    if (first_link == &last)
      return 0;
    first_link->unlink();			// Unlink from list
    return first_link;
  }
  inline struct ilink *head()
  {
    return (first != &last) ? first : 0;
  }
  friend class base_list_iterator;
};


class base_ilist_iterator
{
  base_ilist *list;
  struct ilink **el,*current;
public:
  base_ilist_iterator(base_ilist &list_par) :list(&list_par),
    el(&list_par.first),current(0) {}
  void *next(void)
  {
    /* This is coded to allow push_back() while iterating */
    current= *el;
    if (current == &list->last) return 0;
    el= &current->next;
    return current;
  }
};


template <class T>
class I_List :private base_ilist
{
public:
  I_List() :base_ilist()	{}
  inline void empty()		{ base_ilist::empty(); }
  inline bool is_empty()        { return base_ilist::is_empty(); } 
  inline void append(T* a)	{ base_ilist::append(a); }
  inline void push_back(T* a)	{ base_ilist::push_back(a); }
  inline T* get()		{ return (T*) base_ilist::get(); }
  inline T* head()		{ return (T*) base_ilist::head(); }
#ifndef _lint
  friend class I_List_iterator<T>;
#endif
};


template <class T> class I_List_iterator :public base_ilist_iterator
{
public:
  I_List_iterator(I_List<T> &a) : base_ilist_iterator(a) {}
  inline T* operator++(int) { return (T*) base_ilist_iterator::next(); }
};