include/bits/stl_map.h

// Map implementation -*- C++ -*-

// Copyright (C) 2001, 2002 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library 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, or (at your option)
// any later version.

// This library 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 library; see the file COPYING.  If not, write to the Free
// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
// USA.

// As a special exception, you may use this file as part of a free software
// library without restriction.  Specifically, if other files instantiate
// templates or use macros or inline functions from this file, or you compile
// this file and link it with other files to produce an executable, this
// file does not by itself cause the resulting executable to be covered by
// the GNU General Public License.  This exception does not however
// invalidate any other reasons why the executable file might be covered by
// the GNU General Public License.

/*
 *
 * Copyright (c) 1994
 * Hewlett-Packard Company
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Hewlett-Packard Company makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 *
 * Copyright (c) 1996,1997
 * Silicon Graphics Computer Systems, Inc.
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Silicon Graphics makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 */

/** @file stl_map.h
 *  This is an internal header file, included by other library headers.
 *  You should not attempt to use it directly.
 */

#ifndef __GLIBCPP_INTERNAL_MAP_H
#define __GLIBCPP_INTERNAL_MAP_H

#include <bits/concept_check.h>

namespace std
{
  /**
   *  @brief A standard container made up of (key,value) pairs, which can be
   *  retrieved based on a key, in logarithmic time.
   *
   *  @ingroup Containers
   *  @ingroup Assoc_containers
   *
   *  Meets the requirements of a <a href="tables.html#65">container</a>, a
   *  <a href="tables.html#66">reversible container</a>, and an
   *  <a href="tables.html#69">associative container</a> (using unique keys).
   *  For a @c map<Key,T> the key_type is Key, the mapped_type is T, and the
   *  value_type is std::pair<const Key,T>.
   *
   *  Maps support bidirectional iterators.
   *
   *  @if maint
   *  The private tree data is declared exactly the same way for map and
   *  multimap; the distinction is made entirely in how the tree functions are
   *  called (*_unique versus *_equal, same as the standard).
   *  @endif
  */
  template <typename _Key, typename _Tp, typename _Compare = less<_Key>,
            typename _Alloc = allocator<pair<const _Key, _Tp> > >
    class map
  {
    // concept requirements
    __glibcpp_class_requires(_Tp, _SGIAssignableConcept)
    __glibcpp_class_requires4(_Compare, bool, _Key, _Key, _BinaryFunctionConcept)

  public:
    typedef _Key                                          key_type;
    typedef _Tp                                           mapped_type;
    typedef pair<const _Key, _Tp>                         value_type;
    typedef _Compare                                      key_compare;

    class value_compare
      : public binary_function<value_type, value_type, bool>
      {
        friend class map<_Key,_Tp,_Compare,_Alloc>;
      protected:
        _Compare comp;
        value_compare(_Compare __c) : comp(__c) {}
      public:
        bool operator()(const value_type& __x, const value_type& __y) const
        { return comp(__x.first, __y.first); }
      };

  private:
    /// @if maint  This turns a red-black tree into a [multi]map.  @endif
    typedef _Rb_tree<key_type, value_type,
                     _Select1st<value_type>, key_compare, _Alloc> _Rep_type;
    /// @if maint  The actual tree structure.  @endif
    _Rep_type _M_t;

  public:
    // many of these are specified differently in ISO, but the following are
    // "functionally equivalent"
    typedef typename _Rep_type::allocator_type            allocator_type;
    typedef typename _Rep_type::reference                 reference;
    typedef typename _Rep_type::const_reference           const_reference;
    typedef typename _Rep_type::iterator                  iterator;
    typedef typename _Rep_type::const_iterator            const_iterator;
    typedef typename _Rep_type::size_type                 size_type;
    typedef typename _Rep_type::difference_type           difference_type;
    typedef typename _Rep_type::pointer                   pointer;
    typedef typename _Rep_type::const_pointer             const_pointer;
    typedef typename _Rep_type::reverse_iterator          reverse_iterator;
    typedef typename _Rep_type::const_reverse_iterator    const_reverse_iterator;


    // [23.3.1.1] construct/copy/destroy
    // (get_allocator() is normally listed in this section, but seems to have
    // been accidentally omitted in the printed standard)
    /**
     *  @brief  Default constructor creates no elements.
    */
    map() : _M_t(_Compare(), allocator_type()) { }

    // for some reason this was made a separate function
    /**
     *  @brief  Default constructor creates no elements.
    */
    explicit
    map(const _Compare& __comp, const allocator_type& __a = allocator_type())
      : _M_t(__comp, __a) { }

    /**
     *  @brief  Map copy constructor.
     *  @param  x  A %map of identical element and allocator types.
     *
     *  The newly-created %map uses a copy of the allocation object used
     *  by @a x.
    */
    map(const map& __x)
      : _M_t(__x._M_t) { }

    /**
     *  @brief  Builds a %map from a range.
     *  @param  first  An input iterator.
     *  @param  last  An input iterator.
     *
     *  Create a %map consisting of copies of the elements from [first,last).
     *  This is linear in N if the range is already sorted, and NlogN
     *  otherwise (where N is distance(first,last)).
    */
    template <typename _InputIterator>
      map(_InputIterator __first, _InputIterator __last)
      : _M_t(_Compare(), allocator_type())
      { _M_t.insert_unique(__first, __last); }

    /**
     *  @brief  Builds a %map from a range.
     *  @param  first  An input iterator.
     *  @param  last  An input iterator.
     *  @param  comp  A comparison functor.
     *  @param  a  An allocator object.
     *
     *  Create a %map consisting of copies of the elements from [first,last).
     *  This is linear in N if the range is already sorted, and NlogN
     *  otherwise (where N is distance(first,last)).
    */
    template <typename _InputIterator>
      map(_InputIterator __first, _InputIterator __last,
          const _Compare& __comp, const allocator_type& __a = allocator_type())
      : _M_t(__comp, __a)
      { _M_t.insert_unique(__first, __last); }

    // FIXME There is no dtor declared, but we should have something generated
    // by Doxygen.  I don't know what tags to add to this paragraph to make
    // that happen:
    /**
     *  The dtor only erases the elements, and note that if the elements
     *  themselves are pointers, the pointed-to memory is not touched in any
     *  way.  Managing the pointer is the user's responsibilty.
    */

    /**
     *  @brief  Map assignment operator.
     *  @param  x  A %map of identical element and allocator types.
     *
     *  All the elements of @a x are copied, but unlike the copy constructor,
     *  the allocator object is not copied.
    */
    map&
    operator=(const map& __x)
    {
      _M_t = __x._M_t;
      return *this;
    }

    /// Get a copy of the memory allocation object.
    allocator_type
    get_allocator() const { return _M_t.get_allocator(); }

    // iterators
    /**
     *  Returns a read/write iterator that points to the first pair in the %map.
     *  Iteration is done in ascending order according to the keys.
    */
    iterator
    begin() { return _M_t.begin(); }

    /**
     *  Returns a read-only (constant) iterator that points to the first pair
     *  in the %map.  Iteration is done in ascending order according to the
     *  keys.
    */
    const_iterator
    begin() const { return _M_t.begin(); }

    /**
     *  Returns a read/write iterator that points one past the last pair in the
     *  %map.  Iteration is done in ascending order according to the keys.
    */
    iterator
    end() { return _M_t.end(); }

    /**
     *  Returns a read-only (constant) iterator that points one past the last
     *  pair in the %map.  Iteration is done in ascending order according to the
     *  keys.
    */
    const_iterator
    end() const { return _M_t.end(); }

    /**
     *  Returns a read/write reverse iterator that points to the last pair in
     *  the %map.  Iteration is done in descending order according to the keys.
    */
    reverse_iterator
    rbegin() { return _M_t.rbegin(); }

    /**
     *  Returns a read-only (constant) reverse iterator that points to the last
     *  pair in the %map.  Iteration is done in descending order according to
     *  the keys.
    */
    const_reverse_iterator
    rbegin() const { return _M_t.rbegin(); }

    /**
     *  Returns a read/write reverse iterator that points to one before the
     *  first pair in the %map.  Iteration is done in descending order according
     *  to the keys.
    */
    reverse_iterator
    rend() { return _M_t.rend(); }

    /**
     *  Returns a read-only (constant) reverse iterator that points to one
     *  before the first pair in the %map.  Iteration is done in descending
     *  order according to the keys.
    */
    const_reverse_iterator
    rend() const { return _M_t.rend(); }

    // capacity
    /** Returns true if the %map is empty.  (Thus begin() would equal end().) */
    bool
    empty() const { return _M_t.empty(); }

    /** Returns the size of the %map.  */
    size_type
    size() const { return _M_t.size(); }

    /** Returns the maximum size of the %map.  */
    size_type
    max_size() const { return _M_t.max_size(); }

    // [23.3.1.2] element access
    /**
     *  @brief  Subscript ( @c [] ) access to %map data.
     *  @param  k  The key for which data should be retrieved.
     *  @return  A reference to the data of the (key,data) %pair.
     *
     *  Allows for easy lookup with the subscript ( @c [] ) operator.  Returns
     *  data associated with the key specified in subscript.  If the key does
     *  not exist, a pair with that key is created using default values, which
     *  is then returned.
     *
     *  Lookup requires logarithmic time.
    */
    mapped_type&
    operator[](const key_type& __k)
    {
      // concept requirements
      __glibcpp_function_requires(_DefaultConstructibleConcept<mapped_type>)

      iterator __i = lower_bound(__k);
      // __i->first is greater than or equivalent to __k.
      if (__i == end() || key_comp()(__k, (*__i).first))
        __i = insert(__i, value_type(__k, mapped_type()));
      return (*__i).second;
    }

    // modifiers
    /**
     *  @brief Attempts to insert a std::pair into the %map.
     *  @param  x  Pair to be inserted (see std::make_pair for easy creation of
     *             pairs).
     *  @return  A pair, of which the first element is an iterator that points
     *           to the possibly inserted pair, and the second is a bool that
     *           is true if the pair was actually inserted.
     *
     *  This function attempts to insert a (key, value) %pair into the %map.
     *  A %map relies on unique keys and thus a %pair is only inserted if its
     *  first element (the key) is not already present in the %map.
     *
     *  Insertion requires logarithmic time.
    */
    pair<iterator,bool>
    insert(const value_type& __x)
    { return _M_t.insert_unique(__x); }

    /**
     *  @brief Attempts to insert a std::pair into the %map.
     *  @param  position  An iterator that serves as a hint as to where the
     *                    pair should be inserted.
     *  @param  x  Pair to be inserted (see std::make_pair for easy creation of
     *             pairs).
     *  @return  An iterator that points to the element with key of @a x (may
     *           or may not be the %pair passed in).
     *
     *  This function is not concerned about whether the insertion took place,
     *  and thus does not return a boolean like the single-argument
     *  insert() does.  Note that the first parameter is only a hint and can
     *  potentially improve the performance of the insertion process.  A bad
     *  hint would cause no gains in efficiency.
     *
     *  See http://gcc.gnu.org/onlinedocs/libstdc++/23_containers/howto.html#4
     *  for more on "hinting".
     *
     *  Insertion requires logarithmic time (if the hint is not taken).
    */
    iterator
    insert(iterator position, const value_type& __x)
    { return _M_t.insert_unique(position, __x); }

    /**
     *  @brief A template function that attemps to insert a range of elements.
     *  @param  first  Iterator pointing to the start of the range to be
     *                 inserted.
     *  @param  last  Iterator pointing to the end of the range.
     *
     *  Complexity similar to that of the range constructor.
    */
    template <typename _InputIterator>
      void
      insert(_InputIterator __first, _InputIterator __last)
      { _M_t.insert_unique(__first, __last); }

    /**
     *  @brief Erases an element from a %map.
     *  @param  position  An iterator pointing to the element to be erased.
     *
     *  This function erases an element, pointed to by the given iterator, from
     *  a %map.  Note that this function only erases the element, and that if
     *  the element is itself a pointer, the pointed-to memory is not touched
     *  in any way.  Managing the pointer is the user's responsibilty.
    */
    void
    erase(iterator __position) { _M_t.erase(__position); }

    /**
     *  @brief Erases elements according to the provided key.
     *  @param  x  Key of element to be erased.
     *  @return  The number of elements erased.
     *
     *  This function erases all the elements located by the given key from
     *  a %map.
     *  Note that this function only erases the element, and that if
     *  the element is itself a pointer, the pointed-to memory is not touched
     *  in any way.  Managing the pointer is the user's responsibilty.
    */
    size_type
    erase(const key_type& __x) { return _M_t.erase(__x); }

    /**
     *  @brief Erases a [first,last) range of elements from a %map.
     *  @param  first  Iterator pointing to the start of the range to be erased.
     *  @param  last  Iterator pointing to the end of the range to be erased.
     *
     *  This function erases a sequence of elements from a %map.
     *  Note that this function only erases the element, and that if
     *  the element is itself a pointer, the pointed-to memory is not touched
     *  in any way.  Managing the pointer is the user's responsibilty.
    */
    void
    erase(iterator __first, iterator __last) { _M_t.erase(__first, __last); }

    /**
     *  @brief  Swaps data with another %map.
     *  @param  x  A %map of the same element and allocator types.
     *
     *  This exchanges the elements between two maps in constant time.
     *  (It is only swapping a pointer, an integer, and an instance of
     *  the @c Compare type (which itself is often stateless and empty), so it
     *  should be quite fast.)
     *  Note that the global std::swap() function is specialized such that
     *  std::swap(m1,m2) will feed to this function.
    */
    void
    swap(map& __x) { _M_t.swap(__x._M_t); }

    /**
     *  Erases all elements in a %map.  Note that this function only erases
     *  the elements, and that if the elements themselves are pointers, the
     *  pointed-to memory is not touched in any way.  Managing the pointer is
     *  the user's responsibilty.
    */
    void
    clear() { _M_t.clear(); }

    // observers
    /**
     *  Returns the key comparison object out of which the %map was constructed.
    */
    key_compare
    key_comp() const { return _M_t.key_comp(); }

    /**
     *  Returns a value comparison object, built from the key comparison
     *  object out of which the %map was constructed.
    */
    value_compare
    value_comp() const { return value_compare(_M_t.key_comp()); }

    // [23.3.1.3] map operations
    /**
     *  @brief Tries to locate an element in a %map.
     *  @param  x  Key of (key, value) %pair to be located.
     *  @return  Iterator pointing to sought-after element, or end() if not
     *           found.
     *
     *  This function takes a key and tries to locate the element with which
     *  the key matches.  If successful the function returns an iterator
     *  pointing to the sought after %pair.  If unsuccessful it returns the
     *  past-the-end ( @c end() ) iterator.
    */
    iterator
    find(const key_type& __x) { return _M_t.find(__x); }

    /**
     *  @brief Tries to locate an element in a %map.
     *  @param  x  Key of (key, value) %pair to be located.
     *  @return  Read-only (constant) iterator pointing to sought-after
     *           element, or end() if not found.
     *
     *  This function takes a key and tries to locate the element with which
     *  the key matches.  If successful the function returns a constant iterator
     *  pointing to the sought after %pair. If unsuccessful it returns the
     *  past-the-end ( @c end() ) iterator.
    */
    const_iterator
    find(const key_type& __x) const { return _M_t.find(__x); }

    /**
     *  @brief  Finds the number of elements with given key.
     *  @param  x  Key of (key, value) pairs to be located.
     *  @return  Number of elements with specified key.
     *
     *  This function only makes sense for multimaps; for map the result will
     *  either be 0 (not present) or 1 (present).
    */
    size_type
    count(const key_type& __x) const
    { return _M_t.find(__x) == _M_t.end() ? 0 : 1; }

    /**
     *  @brief Finds the beginning of a subsequence matching given key.
     *  @param  x  Key of (key, value) pair to be located.
     *  @return  Iterator pointing to first element matching given key, or
     *           end() if not found.
     *
     *  This function is useful only with multimaps.  It returns the first
     *  element of a subsequence of elements that matches the given key.  If
     *  unsuccessful it returns an iterator pointing to the first element that
     *  has a greater value than given key or end() if no such element exists.
    */
    iterator
    lower_bound(const key_type& __x) { return _M_t.lower_bound(__x); }

    /**
     *  @brief Finds the beginning of a subsequence matching given key.
     *  @param  x  Key of (key, value) pair to be located.
     *  @return  Read-only (constant) iterator pointing to first element
     *           matching given key, or end() if not found.
     *
     *  This function is useful only with multimaps.  It returns the first
     *  element of a subsequence of elements that matches the given key.  If
     *  unsuccessful the iterator will point to the next greatest element or,
     *  if no such greater element exists, to end().
    */
    const_iterator
    lower_bound(const key_type& __x) const { return _M_t.lower_bound(__x); }

    /**
     *  @brief Finds the end of a subsequence matching given key.
     *  @param  x  Key of (key, value) pair to be located.
     *  @return Iterator pointing to last element matching given key.
     *
     *  This function only makes sense with multimaps.
    */
    iterator
    upper_bound(const key_type& __x) { return _M_t.upper_bound(__x); }

    /**
     *  @brief Finds the end of a subsequence matching given key.
     *  @param  x  Key of (key, value) pair to be located.
     *  @return  Read-only (constant) iterator pointing to last element matching
     *           given key.
     *
     *  This function only makes sense with multimaps.
    */
    const_iterator
    upper_bound(const key_type& __x) const
    { return _M_t.upper_bound(__x); }

    /**
     *  @brief Finds a subsequence matching given key.
     *  @param  x  Key of (key, value) pairs to be located.
     *  @return  Pair of iterators that possibly points to the subsequence
     *           matching given key.
     *
     *  This function returns a pair of which the first
     *  element possibly points to the first element matching the given key
     *  and the second element possibly points to the last element matching the
     *  given key.  If unsuccessful the first element of the returned pair will
     *  contain an iterator pointing to the next greatest element or, if no such
     *  greater element exists, to end().
     *
     *  This function only makes sense for multimaps.
    */
    pair<iterator,iterator>
    equal_range(const key_type& __x)
    { return _M_t.equal_range(__x); }

    /**
     *  @brief Finds a subsequence matching given key.
     *  @param  x  Key of (key, value) pairs to be located.
     *  @return  Pair of read-only (constant) iterators that possibly points to
     *           the subsequence matching given key.
     *
     *  This function returns a pair of which the first
     *  element possibly points to the first element matching the given key
     *  and the second element possibly points to the last element matching the
     *  given key.  If unsuccessful the first element of the returned pair will
     *  contain an iterator pointing to the next greatest element or, if no such
     *  a greater element exists, to end().
     *
     *  This function only makes sense for multimaps.
    */
    pair<const_iterator,const_iterator>
    equal_range(const key_type& __x) const
    { return _M_t.equal_range(__x); }

    template <typename _K1, typename _T1, typename _C1, typename _A1>
    friend bool operator== (const map<_K1,_T1,_C1,_A1>&,
                            const map<_K1,_T1,_C1,_A1>&);
    template <typename _K1, typename _T1, typename _C1, typename _A1>
    friend bool operator< (const map<_K1,_T1,_C1,_A1>&,
                           const map<_K1,_T1,_C1,_A1>&);
  };


  /**
   *  @brief  Map equality comparison.
   *  @param  x  A %map.
   *  @param  y  A %map of the same type as @a x.
   *  @return  True iff the size and elements of the maps are equal.
   *
   *  This is an equivalence relation.  It is linear in the size of the
   *  maps.  Maps are considered equivalent if their sizes are equal,
   *  and if corresponding elements compare equal.
  */
  template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
    inline bool
    operator==(const map<_Key,_Tp,_Compare,_Alloc>& __x,
               const map<_Key,_Tp,_Compare,_Alloc>& __y)
    { return __x._M_t == __y._M_t; }

  /**
   *  @brief  Map ordering relation.
   *  @param  x  A %map.
   *  @param  y  A %map of the same type as @a x.
   *  @return  True iff @a x is lexographically less than @a y.
   *
   *  This is a total ordering relation.  It is linear in the size of the
   *  maps.  The elements must be comparable with @c <.
   *
   *  See std::lexographical_compare() for how the determination is made.
  */
  template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
    inline bool
    operator<(const map<_Key,_Tp,_Compare,_Alloc>& __x,
              const map<_Key,_Tp,_Compare,_Alloc>& __y)
    { return __x._M_t < __y._M_t; }

  /// Based on operator==
  template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
    inline bool
    operator!=(const map<_Key,_Tp,_Compare,_Alloc>& __x,
               const map<_Key,_Tp,_Compare,_Alloc>& __y)
    { return !(__x == __y); }

  /// Based on operator<
  template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
    inline bool
    operator>(const map<_Key,_Tp,_Compare,_Alloc>& __x,
              const map<_Key,_Tp,_Compare,_Alloc>& __y)
    { return __y < __x; }

  /// Based on operator<
  template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
    inline bool
    operator<=(const map<_Key,_Tp,_Compare,_Alloc>& __x,
               const map<_Key,_Tp,_Compare,_Alloc>& __y)
    { return !(__y < __x); }

  /// Based on operator<
  template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
    inline bool
    operator>=(const map<_Key,_Tp,_Compare,_Alloc>& __x,
               const map<_Key,_Tp,_Compare,_Alloc>& __y)
    { return !(__x < __y); }

  /// See std::map::swap().
  template <typename _Key, typename _Tp, typename _Compare, typename _Alloc>
    inline void
    swap(map<_Key,_Tp,_Compare,_Alloc>& __x, map<_Key,_Tp,_Compare,_Alloc>& __y)
    { __x.swap(__y); }
} // namespace std

#endif /* __GLIBCPP_INTERNAL_MAP_H */