// Internal header for TR1 unordered_set and unordered_map -*- C++ -*-

// Copyright (C) 2005, 2006 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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
// 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.

/** @file 
 *  This is a TR1 C++ Library header. 
 */

// This header file defines std::tr1::hashtable, which is used to
// implement std::tr1::unordered_set, std::tr1::unordered_map, 
// std::tr1::unordered_multiset, and std::tr1::unordered_multimap.
// hashtable has many template parameters, partly to accommodate
// the differences between those four classes and partly to 
// accommodate policy choices that go beyond what TR1 calls for.

// Class template hashtable attempts to encapsulate all reasonable
// variation among hash tables that use chaining.  It does not handle
// open addressing.

// References: 
// M. Austern, "A Proposal to Add Hash Tables to the Standard
//    Library (revision 4)," WG21 Document N1456=03-0039, 2003.
// D. E. Knuth, The Art of Computer Programming, v. 3, Sorting and Searching.
// A. Tavori and V. Dreizin, "Policy-Based Data Structures", 2004.
// http://gcc.gnu.org/onlinedocs/libstdc++/ext/pb_ds/index.html

#ifndef _TR1_HASHTABLE
#define _TR1_HASHTABLE 1

#include <utility>		// For std::pair
#include <memory>
#include <iterator>
#include <cstddef>
#include <cstdlib>
#include <cmath>
#include <bits/functexcept.h>
#include <tr1/type_traits>	// For true_type and false_type
#include <tr1/hashtable_policy.h>

namespace std
{ 
_GLIBCXX_BEGIN_NAMESPACE(tr1)

  // Class template hashtable, class definition.
  
  // Meaning of class template hashtable's template parameters
  
  // Key and Value: arbitrary CopyConstructible types.
  
  // Allocator: an allocator type ([lib.allocator.requirements]) whose
  // value type is Value.
  
  // ExtractKey: function object that takes a object of type Value
  // and returns a value of type Key.
  
  // Equal: function object that takes two objects of type k and returns
  // a bool-like value that is true if the two objects are considered equal.
  
  // H1: the hash function.  A unary function object with argument type
  // Key and result type size_t.  Return values should be distributed
  // over the entire range [0, numeric_limits<size_t>:::max()].
  
  // H2: the range-hashing function (in the terminology of Tavori and
  // Dreizin).  A binary function object whose argument types and result
  // type are all size_t.  Given arguments r and N, the return value is
  // in the range [0, N).
  
  // H: the ranged hash function (Tavori and Dreizin). A binary function
  // whose argument types are Key and size_t and whose result type is
  // size_t.  Given arguments k and N, the return value is in the range
  // [0, N).  Default: h(k, N) = h2(h1(k), N).  If H is anything other
  // than the default, H1 and H2 are ignored.
  
  // RehashPolicy: Policy class with three members, all of which govern
  // the bucket count. n_bkt(n) returns a bucket count no smaller
  // than n.  bkt_for_elements(n) returns a bucket count appropriate
  // for an element count of n.  need_rehash(n_bkt, n_elt, n_ins)
  // determines whether, if the current bucket count is n_bkt and the
  // current element count is n_elt, we need to increase the bucket
  // count.  If so, returns make_pair(true, n), where n is the new
  // bucket count.  If not, returns make_pair(false, <anything>).
  
  // ??? Right now it is hard-wired that the number of buckets never
  // shrinks.  Should we allow RehashPolicy to change that?
  
  // cache_hash_code: bool.  true if we store the value of the hash
  // function along with the value.  This is a time-space tradeoff.
  // Storing it may improve lookup speed by reducing the number of times
  // we need to call the Equal function.
  
  // constant_iterators: bool.  true if iterator and const_iterator are
  // both constant iterator types.  This is true for unordered_set and
  // unordered_multiset, false for unordered_map and unordered_multimap.
  
  // unique_keys: bool.  true if the return value of hashtable::count(k)
  // is always at most one, false if it may be an arbitrary number.  This
  // true for unordered_set and unordered_map, false for unordered_multiset
  // and unordered_multimap.
  
  template<typename Key, typename Value, typename Allocator,
	   typename ExtractKey, typename Equal,
	   typename H1, typename H2, typename H, 
	   typename RehashPolicy,
	   bool cache_hash_code,
	   bool constant_iterators,
	   bool unique_keys>
    class hashtable
    : public detail::rehash_base<RehashPolicy,
				 hashtable<Key, Value, Allocator, ExtractKey,
					   Equal, H1, H2, H, RehashPolicy,
					   cache_hash_code, constant_iterators,
					   unique_keys> >,
      public detail::hash_code_base<Key, Value, ExtractKey, Equal, H1, H2, H,
				    cache_hash_code>,
      public detail::map_base<Key, Value, ExtractKey, unique_keys,
			      hashtable<Key, Value, Allocator, ExtractKey,
					Equal, H1, H2, H, RehashPolicy,
					cache_hash_code, constant_iterators,
					unique_keys> >
    {
    public:
      typedef Allocator                                   allocator_type;
      typedef Value                                       value_type;
      typedef Key                                         key_type;
      typedef Equal                                       key_equal;
      // mapped_type, if present, comes from map_base.
      // hasher, if present, comes from hash_code_base.
      typedef typename Allocator::difference_type         difference_type;
      typedef typename Allocator::size_type               size_type;
      typedef typename Allocator::reference               reference;
      typedef typename Allocator::const_reference         const_reference;
      
      typedef detail::node_iterator<value_type, constant_iterators,
				      cache_hash_code>
                                                          local_iterator;
      typedef detail::node_const_iterator<value_type, constant_iterators,
					    cache_hash_code>
                                                          const_local_iterator;

      typedef detail::hashtable_iterator<value_type, constant_iterators,
					   cache_hash_code>
                                                          iterator;
      typedef detail::hashtable_const_iterator<value_type, constant_iterators,
						 cache_hash_code>
                                                          const_iterator;

      template<typename K, typename Pair, typename Hashtable>
        friend struct detail::map_base;

    private:
      typedef detail::hash_node<Value, cache_hash_code> node;
      typedef typename Allocator::template rebind<node>::other
                                                          node_allocator_t;
      typedef typename Allocator::template rebind<node*>::other
                                                          bucket_allocator_t;

      node_allocator_t      m_node_allocator;
      node**                m_buckets;
      size_type             m_bucket_count;
      size_type             m_element_count;
      RehashPolicy          m_rehash_policy;
      
      node*
      m_allocate_node(const value_type& v);
  
      void
      m_deallocate_node(node* n);
  
      void
      m_deallocate_nodes(node**, size_type);

      node**
      m_allocate_buckets(size_type n);
  
      void
      m_deallocate_buckets(node**, size_type n);

    public:			    
      // Constructor, destructor, assignment, swap
      hashtable(size_type bucket_hint,
		const H1&, const H2&, const H&,
		const Equal&, const ExtractKey&,
		const allocator_type&);
  
      template<typename InIter>
        hashtable(InIter first, InIter last,
		  size_type bucket_hint,
		  const H1&, const H2&, const H&, 
		  const Equal&, const ExtractKey&,
		  const allocator_type&);
  
      hashtable(const hashtable&);
      
      hashtable&
      operator=(const hashtable&);
  
      ~hashtable();

      void swap(hashtable&);

      // Basic container operations
      iterator
      begin()
      {
	iterator i(m_buckets);
	if (!i.m_cur_node)
	  i.m_incr_bucket();
	return i;
      }

      const_iterator
      begin() const
      {
	const_iterator i(m_buckets);
	if (!i.m_cur_node)
	  i.m_incr_bucket();
	return i;
      }

      iterator
      end()
      { return iterator(m_buckets + m_bucket_count); }

      const_iterator
      end() const
      { return const_iterator(m_buckets + m_bucket_count); }

      size_type
      size() const
      { return m_element_count; }
  
      bool
      empty() const
      { return size() == 0; }

      allocator_type
      get_allocator() const
      { return m_node_allocator; }
  
      size_type
      max_size() const
      { return m_node_allocator.max_size(); }

      // Observers
      key_equal
      key_eq() const
      { return this->m_eq; }

      // hash_function, if present, comes from hash_code_base.

      // Bucket operations
      size_type
      bucket_count() const
      { return m_bucket_count; }
  
      size_type
      max_bucket_count() const
      { return max_size(); }
  
      size_type
      bucket_size(size_type n) const
      { return std::distance(begin(n), end(n)); }
  
      size_type
      bucket(const key_type& k) const
      { 
	return this->bucket_index(k, this->m_hash_code(k),
				  this->m_bucket_count);
      }

      local_iterator
      begin(size_type n)
      { return local_iterator(m_buckets[n]); }
  
      local_iterator
      end(size_type)
      { return local_iterator(0); }
  
      const_local_iterator
      begin(size_type n) const
      { return const_local_iterator(m_buckets[n]); }
  
      const_local_iterator
      end(size_type) const
      { return const_local_iterator(0); }

      float
      load_factor() const
      { 
	return static_cast<float>(size()) / static_cast<float>(bucket_count());
      }

      // max_load_factor, if present, comes from rehash_base.

      // Generalization of max_load_factor.  Extension, not found in TR1.  Only
      // useful if RehashPolicy is something other than the default.
      const RehashPolicy&
      rehash_policy() const
      { return m_rehash_policy; }
      
      void 
      rehash_policy(const RehashPolicy&);

      // Lookup.
      iterator
      find(const key_type& k);

      const_iterator
      find(const key_type& k) const;

      size_type
      count(const key_type& k) const;

      std::pair<iterator, iterator>
      equal_range(const key_type& k);

      std::pair<const_iterator, const_iterator>
      equal_range(const key_type& k) const;

    private:			// Find, insert and erase helper functions
      // ??? This dispatching is a workaround for the fact that we don't
      // have partial specialization of member templates; it would be
      // better to just specialize insert on unique_keys.  There may be a
      // cleaner workaround.
      typedef typename __gnu_cxx::__conditional_type<unique_keys,
		       	    std::pair<iterator, bool>, iterator>::__type
        Insert_Return_Type;

      typedef typename __gnu_cxx::__conditional_type<unique_keys,
					   std::_Select1st<Insert_Return_Type>,
				  	   std::_Identity<Insert_Return_Type>
                                   >::__type
        Insert_Conv_Type;

      node*
      m_find_node(node*, const key_type&,
		  typename hashtable::hash_code_t) const;

      iterator
      m_insert_bucket(const value_type&, size_type,
		      typename hashtable::hash_code_t);

      std::pair<iterator, bool>
      m_insert(const value_type&, std::tr1::true_type);

      iterator
      m_insert(const value_type&, std::tr1::false_type);

      void
      m_erase_node(node*, node**);

    public:				
      // Insert and erase
      Insert_Return_Type
      insert(const value_type& v) 
      { return m_insert(v, std::tr1::integral_constant<bool, unique_keys>()); }

      iterator
      insert(iterator, const value_type& v)
      { return iterator(Insert_Conv_Type()(this->insert(v))); }

      const_iterator
      insert(const_iterator, const value_type& v)
      { return const_iterator(Insert_Conv_Type()(this->insert(v))); }

      template<typename InIter>
        void
        insert(InIter first, InIter last);

      iterator
      erase(iterator);

      const_iterator
      erase(const_iterator);

      size_type
      erase(const key_type&);

      iterator
      erase(iterator, iterator);

      const_iterator
      erase(const_iterator, const_iterator);

      void
      clear();

      // Set number of buckets to be appropriate for container of n element.
      void rehash(size_type n);
      
    private:
      // Unconditionally change size of bucket array to n.
      void m_rehash(size_type n);
    };


  // Definitions of class template hashtable's out-of-line member functions.
  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    typename hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::node*
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    m_allocate_node(const value_type& v)
    {
      node* n = m_node_allocator.allocate(1);
      try
	{
	  get_allocator().construct(&n->m_v, v);
	  n->m_next = 0;
	  return n;
	}
      catch(...)
	{
	  m_node_allocator.deallocate(n, 1);
	  __throw_exception_again;
	}
    }

  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    void
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    m_deallocate_node(node* n)
    {
      get_allocator().destroy(&n->m_v);
      m_node_allocator.deallocate(n, 1);
    }

  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    void
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    m_deallocate_nodes(node** array, size_type n)
    {
      for (size_type i = 0; i < n; ++i)
	{
	  node* p = array[i];
	  while (p)
	    {
	      node* tmp = p;
	      p = p->m_next;
	      m_deallocate_node(tmp);
	    }
	  array[i] = 0;
	}
    }

  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    typename hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::node**
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    m_allocate_buckets(size_type n)
    {
      bucket_allocator_t alloc(m_node_allocator);

      // We allocate one extra bucket to hold a sentinel, an arbitrary
      // non-null pointer.  Iterator increment relies on this.
      node** p = alloc.allocate(n + 1);
      std::fill(p, p + n, (node*) 0);
      p[n] = reinterpret_cast<node*>(0x1000);
      return p;
    }

  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    void
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    m_deallocate_buckets(node** p, size_type n)
    {
      bucket_allocator_t alloc(m_node_allocator);
      alloc.deallocate(p, n + 1);
    }

  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    hashtable(size_type bucket_hint,
	      const H1& h1, const H2& h2, const H& h,
	      const Eq& eq, const Ex& exk,
	      const allocator_type& a)
    : detail::rehash_base<RP, hashtable>(),
      detail::hash_code_base<K, V, Ex, Eq, H1, H2, H, c>(exk, eq, h1, h2, h),
      detail::map_base<K, V, Ex, u, hashtable>(),
      m_node_allocator(a),
      m_bucket_count(0),
      m_element_count(0),
      m_rehash_policy()
    {
      m_bucket_count = m_rehash_policy.next_bkt(bucket_hint);
      m_buckets = m_allocate_buckets(m_bucket_count);
    }

  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    template<typename InIter>
      hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
      hashtable(InIter f, InIter l,
		size_type bucket_hint,
		const H1& h1, const H2& h2, const H& h,
		const Eq& eq, const Ex& exk,
		const allocator_type& a)
      : detail::rehash_base<RP, hashtable>(),
	detail::hash_code_base<K, V, Ex, Eq, H1, H2, H, c>(exk, eq,
							     h1, h2, h),
	detail::map_base<K, V, Ex, u, hashtable>(),
	m_node_allocator(a),
	m_bucket_count(0),
	m_element_count(0),
	m_rehash_policy()
      {
	m_bucket_count = std::max(m_rehash_policy.next_bkt(bucket_hint),
				  m_rehash_policy.
				  bkt_for_elements(detail::
						   distance_fw(f, l)));
	m_buckets = m_allocate_buckets(m_bucket_count);
	try
	  {
	    for (; f != l; ++f)
	      this->insert(*f);
	  }
	catch(...)
	  {
	    clear();
	    m_deallocate_buckets(m_buckets, m_bucket_count);
	    __throw_exception_again;
	  }
      }
  
  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    hashtable(const hashtable& ht)
    : detail::rehash_base<RP, hashtable>(ht),
      detail::hash_code_base<K, V, Ex, Eq, H1, H2, H, c>(ht),
      detail::map_base<K, V, Ex, u, hashtable>(ht),
      m_node_allocator(ht.get_allocator()),
      m_bucket_count(ht.m_bucket_count),
      m_element_count(ht.m_element_count),
      m_rehash_policy(ht.m_rehash_policy)
    {
      m_buckets = m_allocate_buckets(m_bucket_count);
      try
	{
	  for (size_type i = 0; i < ht.m_bucket_count; ++i)
	    {
	      node* n = ht.m_buckets[i];
	      node** tail = m_buckets + i;
	      while (n)
		{
		  *tail = m_allocate_node(n->m_v);
		  this->copy_code(*tail, n);
		  tail = &((*tail)->m_next);
		  n = n->m_next;
		}
	    }
	}
      catch(...)
	{
	  clear();
	  m_deallocate_buckets(m_buckets, m_bucket_count);
	  __throw_exception_again;
	}
    }

  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>&
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    operator=(const hashtable& ht)
    {
      hashtable tmp(ht);
      this->swap(tmp);
      return *this;
    }

  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    ~hashtable()
    {
      clear();
      m_deallocate_buckets(m_buckets, m_bucket_count);
    }

  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    void
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    swap(hashtable& x)
    {
      // The only base class with member variables is hash_code_base.  We
      // define hash_code_base::m_swap because different specializations
      // have different members.
      detail::hash_code_base<K, V, Ex, Eq, H1, H2, H, c>::m_swap(x);

      // _GLIBCXX_RESOLVE_LIB_DEFECTS
      // 431. Swapping containers with unequal allocators.
      std::__alloc_swap<node_allocator_t>::_S_do_it(m_node_allocator,
						    x.m_node_allocator);

      std::swap(m_rehash_policy, x.m_rehash_policy);
      std::swap(m_buckets, x.m_buckets);
      std::swap(m_bucket_count, x.m_bucket_count);
      std::swap(m_element_count, x.m_element_count);
    }

  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    void
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    rehash_policy(const RP& pol)
    {
      m_rehash_policy = pol;
      size_type n_bkt = pol.bkt_for_elements(m_element_count);
      if (n_bkt > m_bucket_count)
	m_rehash(n_bkt);
    }

  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    typename hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::iterator
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    find(const key_type& k)
    {
      typename hashtable::hash_code_t code = this->m_hash_code(k);
      std::size_t n = this->bucket_index(k, code, this->bucket_count());
      node* p = m_find_node(m_buckets[n], k, code);
      return p ? iterator(p, m_buckets + n) : this->end();
    }

  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    typename hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::const_iterator
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    find(const key_type& k) const
    {
      typename hashtable::hash_code_t code = this->m_hash_code(k);
      std::size_t n = this->bucket_index(k, code, this->bucket_count());
      node* p = m_find_node(m_buckets[n], k, code);
      return p ? const_iterator(p, m_buckets + n) : this->end();
    }

  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    typename hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::size_type
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    count(const key_type& k) const
    {
      typename hashtable::hash_code_t code = this->m_hash_code(k);
      std::size_t n = this->bucket_index(k, code, this->bucket_count());
      std::size_t result = 0;
      for (node* p = m_buckets[n]; p; p = p->m_next)
	if (this->compare(k, code, p))
	  ++result;
      return result;
    }

  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    std::pair<typename hashtable<K, V, A, Ex, Eq, H1,
				 H2, H, RP, c, ci, u>::iterator,
	      typename hashtable<K, V, A, Ex, Eq, H1,
				 H2, H, RP, c, ci, u>::iterator>
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    equal_range(const key_type& k)
    {
      typename hashtable::hash_code_t code = this->m_hash_code(k);
      std::size_t n = this->bucket_index(k, code, this->bucket_count());
      node** head = m_buckets + n;
      node* p = m_find_node(*head, k, code);
      
      if (p)
	{
	  node* p1 = p->m_next;
	  for (; p1; p1 = p1->m_next)
	    if (!this->compare(k, code, p1))
	      break;

	  iterator first(p, head);
	  iterator last(p1, head);
	  if (!p1)
	    last.m_incr_bucket();
	  return std::make_pair(first, last);
	}
      else
	return std::make_pair(this->end(), this->end());
    }

  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    std::pair<typename hashtable<K, V, A, Ex, Eq, H1,
				 H2, H, RP, c, ci, u>::const_iterator,
	      typename hashtable<K, V, A, Ex, Eq, H1,
				 H2, H, RP, c, ci, u>::const_iterator>
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    equal_range(const key_type& k) const
    {
      typename hashtable::hash_code_t code = this->m_hash_code(k);
      std::size_t n = this->bucket_index(k, code, this->bucket_count());
      node** head = m_buckets + n;
      node* p = m_find_node(*head, k, code);

      if (p)
	{
	  node* p1 = p->m_next;
	  for (; p1; p1 = p1->m_next)
	    if (!this->compare(k, code, p1))
	      break;

	  const_iterator first(p, head);
	  const_iterator last(p1, head);
	  if (!p1)
	    last.m_incr_bucket();
	  return std::make_pair(first, last);
	}
      else
	return std::make_pair(this->end(), this->end());
    }

  // Find the node whose key compares equal to k, beginning the search
  // at p (usually the head of a bucket).  Return nil if no node is found.
  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    typename hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::node* 
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    m_find_node(node* p, const key_type& k,
		typename hashtable::hash_code_t code) const
    {
      for (; p; p = p->m_next)
	if (this->compare(k, code, p))
	  return p;
      return false;
    }

  // Insert v in bucket n (assumes no element with its key already present).
  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    typename hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::iterator
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    m_insert_bucket(const value_type& v, size_type n,
		    typename hashtable::hash_code_t code)
    {
      std::pair<bool, std::size_t> do_rehash
	= m_rehash_policy.need_rehash(m_bucket_count, m_element_count, 1);

      // Allocate the new node before doing the rehash so that we don't
      // do a rehash if the allocation throws.
      node* new_node = m_allocate_node(v);

      try
	{
	  if (do_rehash.first)
	    {
	      const key_type& k = this->m_extract(v);
	      n = this->bucket_index(k, code, do_rehash.second);
	      m_rehash(do_rehash.second);
	    }

	  new_node->m_next = m_buckets[n];
	  this->store_code(new_node, code);
	  m_buckets[n] = new_node;
	  ++m_element_count;
	  return iterator(new_node, m_buckets + n);
	}
      catch(...)
	{
	  m_deallocate_node(new_node);
	  __throw_exception_again;
	}
    }

  // Insert v if no element with its key is already present.
  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    std::pair<typename hashtable<K, V, A, Ex, Eq, H1,
				 H2, H, RP, c, ci, u>::iterator, bool>
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    m_insert(const value_type& v, std::tr1::true_type)
    {
      const key_type& k = this->m_extract(v);
      typename hashtable::hash_code_t code = this->m_hash_code(k);
      size_type n = this->bucket_index(k, code, m_bucket_count);

      if (node* p = m_find_node(m_buckets[n], k, code))
	return std::make_pair(iterator(p, m_buckets + n), false);
      return std::make_pair(m_insert_bucket(v, n, code), true);
    }
  
  // Insert v unconditionally.
  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    typename hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::iterator
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    m_insert(const value_type& v, std::tr1::false_type)
    {
      std::pair<bool, std::size_t> do_rehash
	= m_rehash_policy.need_rehash(m_bucket_count, m_element_count, 1);
      if (do_rehash.first)
	m_rehash(do_rehash.second);
 
      const key_type& k = this->m_extract(v);
      typename hashtable::hash_code_t code = this->m_hash_code(k);
      size_type n = this->bucket_index(k, code, m_bucket_count);

      // First find the node, avoid leaking new_node if compare throws.
      node* prev = m_find_node(m_buckets[n], k, code);
      node* new_node = m_allocate_node(v);

      if (prev)
	{
	  new_node->m_next = prev->m_next;
	  prev->m_next = new_node;
	}
      else
	{
	  new_node->m_next = m_buckets[n];
	  m_buckets[n] = new_node;
	}
      this->store_code(new_node, code);

      ++m_element_count;
      return iterator(new_node, m_buckets + n);
    }

  // For erase(iterator) and erase(const_iterator).
  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    void
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    m_erase_node(node* p, node** b)
    {
      node* cur = *b;
      if (cur == p)
	*b = cur->m_next;
      else
	{
	  node* next = cur->m_next;
	  while (next != p)
	    {
	      cur = next;
	      next = cur->m_next;
	    }
	  cur->m_next = next->m_next;
	}

      m_deallocate_node(p);
      --m_element_count;
    }

  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    template<typename InIter>
      void 
      hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
      insert(InIter first, InIter last)
      {
	size_type n_elt = detail::distance_fw(first, last);
	std::pair<bool, std::size_t> do_rehash
	  = m_rehash_policy.need_rehash(m_bucket_count, m_element_count, n_elt);
	if (do_rehash.first)
	  m_rehash(do_rehash.second);

	for (; first != last; ++first)
	  this->insert(*first);
      }

  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    typename hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::iterator
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    erase(iterator it)
    {
      iterator result = it;
      ++result;
      m_erase_node(it.m_cur_node, it.m_cur_bucket);
      return result;
    }

  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    typename hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::const_iterator
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    erase(const_iterator it)
    {
      const_iterator result = it;
      ++result;
      m_erase_node(it.m_cur_node, it.m_cur_bucket);
      return result;
    }

  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    typename hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::size_type
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    erase(const key_type& k)
    {
      typename hashtable::hash_code_t code = this->m_hash_code(k);
      std::size_t n = this->bucket_index(k, code, m_bucket_count);
      size_type result = 0;
      
      node** slot = m_buckets + n;
      while (*slot && !this->compare(k, code, *slot))
	slot = &((*slot)->m_next);

      while (*slot && this->compare(k, code, *slot))
	{
	  node* p = *slot;
	  *slot = p->m_next;
	  m_deallocate_node(p);
	  --m_element_count;
	  ++result;
	}

      return result;
    }

  // ??? This could be optimized by taking advantage of the bucket
  // structure, but it's not clear that it's worth doing.  It probably
  // wouldn't even be an optimization unless the load factor is large.
  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    typename hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::iterator
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    erase(iterator first, iterator last)
    {
      while (first != last)
	first = this->erase(first);
      return last;
    }
  
  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    typename hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::const_iterator
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    erase(const_iterator first, const_iterator last)
    {
      while (first != last)
	first = this->erase(first);
      return last;
    }

  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    void
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    clear()
    {
      m_deallocate_nodes(m_buckets, m_bucket_count);
      m_element_count = 0;
    }
 
  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    void
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    rehash(size_type n)
    {
      m_rehash(std::max(m_rehash_policy.next_bkt(n),
			m_rehash_policy.bkt_for_elements(m_element_count
							 + 1)));
    }

  template<typename K, typename V, 
	   typename A, typename Ex, typename Eq,
	   typename H1, typename H2, typename H, typename RP,
	   bool c, bool ci, bool u>
    void
    hashtable<K, V, A, Ex, Eq, H1, H2, H, RP, c, ci, u>::
    m_rehash(size_type n)
    {
      node** new_array = m_allocate_buckets(n);
      try
	{
	  for (size_type i = 0; i < m_bucket_count; ++i)
	    while (node* p = m_buckets[i])
	      {
		std::size_t new_index = this->bucket_index(p, n);
		m_buckets[i] = p->m_next;
		p->m_next = new_array[new_index];
		new_array[new_index] = p;
	      }
	  m_deallocate_buckets(m_buckets, m_bucket_count);
	  m_bucket_count = n;
	  m_buckets = new_array;
	}
      catch(...)
	{
	  // A failure here means that a hash function threw an exception.
	  // We can't restore the previous state without calling the hash
	  // function again, so the only sensible recovery is to delete
	  // everything.
	  m_deallocate_nodes(new_array, n);
	  m_deallocate_buckets(new_array, n);
	  m_deallocate_nodes(m_buckets, m_bucket_count);
	  m_element_count = 0;
	  __throw_exception_again;
	}
    }

_GLIBCXX_END_NAMESPACE
} // namespace std::tr1

#endif // _TR1_HASHTABLE