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// -*- C++ -*-

// Copyright (C) 2005, 2006, 2009 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 3, 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.

// Under Section 7 of GPL version 3, you are granted additional

// permissions described in the GCC Runtime Library Exception, version

// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and

// a copy of the GCC Runtime Library Exception along with this program;

// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see

// <http://www.gnu.org/licenses/>.

// Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.

// Permission to use, copy, modify, sell, and distribute this software

// is hereby granted without fee, provided that the above copyright

// notice appears in all copies, and that both that copyright notice

// and this permission notice appear in supporting documentation. None

// of the above authors, nor IBM Haifa Research Laboratories, make any

// representation about the suitability of this software for any

// purpose. It is provided "as is" without express or implied

// warranty.

/**

 * @file hash_policy.hpp

 * Contains hash-related policies.

 */

#ifndef PB_DS_HASH_POLICY_HPP

#define PB_DS_HASH_POLICY_HPP

#include <algorithm>

#include <vector>

#include <cmath>

#include <ext/pb_ds/exception.hpp>

#include <ext/pb_ds/detail/type_utils.hpp>

#include <ext/pb_ds/detail/hash_fn/mask_based_range_hashing.hpp>

#include <ext/pb_ds/detail/hash_fn/mod_based_range_hashing.hpp>

#include <ext/pb_ds/detail/resize_policy/hash_load_check_resize_trigger_size_base.hpp>

namespace __gnu_pbds

{

  // A null hash function, indicating that the combining hash function

  // is actually a ranged hash function.

  struct null_hash_fn

  { };

  // A null probe function, indicating that the combining probe

  // function is actually a ranged probe function.

  struct null_probe_fn

  { };

#define PB_DS_CLASS_T_DEC template<typename Size_Type>

#define PB_DS_CLASS_C_DEC linear_probe_fn<Size_Type>

  // A probe sequence policy using fixed increments.

  template<typename Size_Type = size_t>

  class linear_probe_fn

  {

  public:

    typedef Size_Type size_type;

    void

    swap(PB_DS_CLASS_C_DEC& other);

  protected:

    // Returns the i-th offset from the hash value.

    inline size_type

    operator()(size_type i) const;

  };

#include <ext/pb_ds/detail/hash_fn/linear_probe_fn_imp.hpp>

#undef PB_DS_CLASS_T_DEC

#undef PB_DS_CLASS_C_DEC

#define PB_DS_CLASS_T_DEC template<typename Size_Type>

#define PB_DS_CLASS_C_DEC quadratic_probe_fn<Size_Type>

  // A probe sequence policy using square increments.

  template<typename Size_Type = size_t>

  class quadratic_probe_fn

  {

  public:

    typedef Size_Type size_type;

    void

    swap(PB_DS_CLASS_C_DEC& other);

  protected:

    // Returns the i-th offset from the hash value.

    inline size_type

    operator()(size_type i) const;

  };

#include <ext/pb_ds/detail/hash_fn/quadratic_probe_fn_imp.hpp>

#undef PB_DS_CLASS_T_DEC

#undef PB_DS_CLASS_C_DEC

#define PB_DS_CLASS_T_DEC template<typename Size_Type>

#define PB_DS_CLASS_C_DEC direct_mask_range_hashing<Size_Type>

  // A mask range-hashing class (uses a bit-mask).

  template<typename Size_Type = size_t>

  class direct_mask_range_hashing

  : public detail::mask_based_range_hashing<Size_Type>

  {

  private:

    typedef detail::mask_based_range_hashing<Size_Type> mask_based_base;

  public:

    typedef Size_Type size_type;

    void

    swap(PB_DS_CLASS_C_DEC& other);

  protected:

    void

    notify_resized(size_type size);

    // Transforms the __hash value hash into a ranged-hash value

    // (using a bit-mask).

    inline size_type

    operator()(size_type hash) const;

  };

#include <ext/pb_ds/detail/hash_fn/direct_mask_range_hashing_imp.hpp>

#undef PB_DS_CLASS_T_DEC

#undef PB_DS_CLASS_C_DEC

#define PB_DS_CLASS_T_DEC template<typename Size_Type>

#define PB_DS_CLASS_C_DEC direct_mod_range_hashing<Size_Type>

  // A mod range-hashing class (uses the modulo function).

  template<typename Size_Type = size_t>

  class direct_mod_range_hashing

  : public detail::mod_based_range_hashing<Size_Type>

  {

  public:

    typedef Size_Type size_type;

    void

    swap(PB_DS_CLASS_C_DEC& other);

  protected:

    void

    notify_resized(size_type size);

    // Transforms the __hash value hash into a ranged-hash value

    // (using a modulo operation).

    inline size_type

    operator()(size_type hash) const;

  private:

    typedef detail::mod_based_range_hashing<size_type> mod_based_base;

  };

#include <ext/pb_ds/detail/hash_fn/direct_mod_range_hashing_imp.hpp>

#undef PB_DS_CLASS_T_DEC

#undef PB_DS_CLASS_C_DEC

#define PB_DS_CLASS_T_DEC template<bool External_Load_Access, typename Size_Type>

#define PB_DS_CLASS_C_DEC hash_load_check_resize_trigger<External_Load_Access, Size_Type>

#define PB_DS_SIZE_BASE_C_DEC detail::hash_load_check_resize_trigger_size_base<Size_Type, External_Load_Access>

  // A resize trigger policy based on a load check. It keeps the

  // load factor between some load factors load_min and load_max.

  template<bool External_Load_Access = false, typename Size_Type = size_t>

  class hash_load_check_resize_trigger : private PB_DS_SIZE_BASE_C_DEC

  {

  public:

    typedef Size_Type size_type;

    enum

      {

        external_load_access = External_Load_Access

      };

    // Default constructor, or constructor taking load_min and

    // load_max load factors between which this policy will keep the

    // actual load.

    hash_load_check_resize_trigger(float load_min = 0.125,

                                   float load_max = 0.5);

    void

    swap(hash_load_check_resize_trigger& other);

    virtual

    ~hash_load_check_resize_trigger();

    // Returns a pair of the minimal and maximal loads, respectively.

    inline std::pair<float, float>

    get_loads() const;

    // Sets the loads through a pair of the minimal and maximal

    // loads, respectively.

    void

    set_loads(std::pair<float, float> load_pair);

  protected:

    inline void

    notify_insert_search_start();

    inline void

    notify_insert_search_collision();

    inline void

    notify_insert_search_end();

    inline void

    notify_find_search_start();

    inline void

    notify_find_search_collision();

    inline void

    notify_find_search_end();

    inline void

    notify_erase_search_start();

    inline void

    notify_erase_search_collision();

    inline void

    notify_erase_search_end();

    // Notifies an element was inserted. The total number of entries

    // in the table is num_entries.

    inline void

    notify_inserted(size_type num_entries);

    inline void

    notify_erased(size_type num_entries);

    // Notifies the table was cleared.

    void

    notify_cleared();

    // Notifies the table was resized as a result of this object's

    // signifying that a resize is needed.

    void

    notify_resized(size_type new_size);

    void

    notify_externally_resized(size_type new_size);

    inline bool

    is_resize_needed() const;

    inline bool

    is_grow_needed(size_type size, size_type num_entries) const;

  private:

    virtual void

    do_resize(size_type new_size);

    typedef PB_DS_SIZE_BASE_C_DEC size_base;

#ifdef _GLIBCXX_DEBUG

    void

    assert_valid() const;

#endif 

    float       m_load_min;

    float       m_load_max;

    size_type   m_next_shrink_size;

    size_type   m_next_grow_size;

    bool        m_resize_needed;

  };

#include <ext/pb_ds/detail/resize_policy/hash_load_check_resize_trigger_imp.hpp>

#undef PB_DS_CLASS_T_DEC

#undef PB_DS_CLASS_C_DEC

#undef PB_DS_SIZE_BASE_C_DEC

#define PB_DS_CLASS_T_DEC template<bool External_Load_Access, typename Size_Type>

#define PB_DS_CLASS_C_DEC cc_hash_max_collision_check_resize_trigger<External_Load_Access, Size_Type>

  // A resize trigger policy based on collision checks. It keeps the

  // simulated load factor lower than some given load factor.

  template<bool External_Load_Access = false, typename Size_Type = size_t>

  class cc_hash_max_collision_check_resize_trigger

  {

  public:

    typedef Size_Type size_type;

    enum

      {

        external_load_access = External_Load_Access

      };

    // Default constructor, or constructor taking load, a __load

    // factor which it will attempt to maintain.

    cc_hash_max_collision_check_resize_trigger(float load = 0.5);

    void

    swap(PB_DS_CLASS_C_DEC& other);

    // Returns the current load.

    inline float

    get_load() const;

    // Sets the load; does not resize the container.

    void

    set_load(float load);

  protected:

    inline void

    notify_insert_search_start();

    inline void

    notify_insert_search_collision();

    inline void

    notify_insert_search_end();

    inline void

    notify_find_search_start();

    inline void

    notify_find_search_collision();

    inline void

    notify_find_search_end();

    inline void

    notify_erase_search_start();

    inline void

    notify_erase_search_collision();

    inline void

    notify_erase_search_end();

    inline void

    notify_inserted(size_type num_entries);

    inline void

    notify_erased(size_type num_entries);

    void

    notify_cleared();

    // Notifies the table was resized as a result of this object's

    // signifying that a resize is needed.

    void

    notify_resized(size_type new_size);

    void

    notify_externally_resized(size_type new_size);

    inline bool

    is_resize_needed() const;

    inline bool

    is_grow_needed(size_type size, size_type num_entries) const;

  private:

    void

    calc_max_num_coll();

    inline void

    calc_resize_needed();

    float       m_load;

    size_type   m_size;

    size_type   m_num_col;

    size_type   m_max_col;

    bool        m_resize_needed;

  };

#include <ext/pb_ds/detail/resize_policy/cc_hash_max_collision_check_resize_trigger_imp.hpp>

#undef PB_DS_CLASS_T_DEC

#undef PB_DS_CLASS_C_DEC

#define PB_DS_CLASS_T_DEC template<typename Size_Type>

#define PB_DS_CLASS_C_DEC hash_exponential_size_policy<Size_Type>

  // A size policy whose sequence of sizes form an exponential

  // sequence (typically powers of 2.

  template<typename Size_Type = size_t>

  class hash_exponential_size_policy

  {

  public:

    typedef Size_Type size_type;

    // Default constructor, or onstructor taking a start_size, or

    // constructor taking a start size and grow_factor. The policy

    // will use the sequence of sizes start_size, start_size*

    // grow_factor, start_size* grow_factor^2, ...

    hash_exponential_size_policy(size_type start_size = 8,

                                 size_type grow_factor = 2);

    void

    swap(PB_DS_CLASS_C_DEC& other);

  protected:

    size_type

    get_nearest_larger_size(size_type size) const;

    size_type

    get_nearest_smaller_size(size_type size) const;

  private:

    size_type m_start_size;

    size_type m_grow_factor;

  };

#include <ext/pb_ds/detail/resize_policy/hash_exponential_size_policy_imp.hpp>

#undef PB_DS_CLASS_T_DEC

#undef PB_DS_CLASS_C_DEC

#define PB_DS_CLASS_T_DEC

#define PB_DS_CLASS_C_DEC hash_prime_size_policy

  // A size policy whose sequence of sizes form a nearly-exponential

  // sequence of primes.

  class hash_prime_size_policy

  {

  public:

    // Size type.

    typedef size_t size_type;

    // Default constructor, or onstructor taking a start_size The

    // policy will use the sequence of sizes approximately

    // start_size, start_size* 2, start_size* 2^2, ...

    hash_prime_size_policy(size_type start_size = 8);

    inline void

    swap(PB_DS_CLASS_C_DEC& other);

  protected:

    size_type

    get_nearest_larger_size(size_type size) const;

    size_type

    get_nearest_smaller_size(size_type size) const;

  private:

    size_type m_start_size;

  };

#include <ext/pb_ds/detail/resize_policy/hash_prime_size_policy_imp.hpp>

#undef PB_DS_CLASS_T_DEC

#undef PB_DS_CLASS_C_DEC

#define PB_DS_CLASS_T_DEC template<typename Size_Policy, typename Trigger_Policy, bool External_Size_Access, typename Size_Type>

#define PB_DS_CLASS_C_DEC hash_standard_resize_policy<Size_Policy, Trigger_Policy, External_Size_Access, Size_Type>

  // A resize policy which delegates operations to size and trigger policies.

  template<typename Size_Policy = hash_exponential_size_policy<>,

           typename Trigger_Policy = hash_load_check_resize_trigger<>,

           bool External_Size_Access = false,

           typename Size_Type = size_t>

  class hash_standard_resize_policy

  : public Size_Policy, public Trigger_Policy

  {

  public:

    typedef Size_Type           size_type;

    typedef Trigger_Policy      trigger_policy;

    typedef Size_Policy         size_policy;

    enum

      {

        external_size_access = External_Size_Access

      };

    // Default constructor.

    hash_standard_resize_policy();

    // constructor taking some policies r_size_policy will be copied

    // by the Size_Policy object of this object.

    hash_standard_resize_policy(const Size_Policy& r_size_policy);

    // constructor taking some policies. r_size_policy will be

    // copied by the Size_Policy object of this

    // object. r_trigger_policy will be copied by the Trigger_Policy

    // object of this object.

    hash_standard_resize_policy(const Size_Policy& r_size_policy,

                                const Trigger_Policy& r_trigger_policy);

    virtual

    ~hash_standard_resize_policy();

    inline void

    swap(PB_DS_CLASS_C_DEC& other);

    // Access to the Size_Policy object used.

    Size_Policy&

    get_size_policy();

    // Const access to the Size_Policy object used.

    const Size_Policy&

    get_size_policy() const;

    // Access to the Trigger_Policy object used.

    Trigger_Policy&

    get_trigger_policy();

    // Access to the Trigger_Policy object used.

    const Trigger_Policy&

    get_trigger_policy() const;

    // Returns the actual size of the container.

    inline size_type

    get_actual_size() const;

    // Resizes the container to suggested_new_size, a suggested size

    // (the actual size will be determined by the Size_Policy

    // object).

    void

    resize(size_type suggested_new_size);

  protected:

    inline void

    notify_insert_search_start();

    inline void

    notify_insert_search_collision();

    inline void

    notify_insert_search_end();

    inline void

    notify_find_search_start();

    inline void

    notify_find_search_collision();

    inline void

    notify_find_search_end();

    inline void

    notify_erase_search_start();

    inline void

    notify_erase_search_collision();

    inline void

    notify_erase_search_end();

    inline void

    notify_inserted(size_type num_e);

    inline void

    notify_erased(size_type num_e);

    void

    notify_cleared();

    void

    notify_resized(size_type new_size);

    inline bool

    is_resize_needed() const;

    // Queries what the new size should be, when the container is

    // resized naturally. The current __size of the container is

    // size, and the number of used entries within the container is

    // num_used_e.

    size_type

    get_new_size(size_type size, size_type num_used_e) const;

  private:

    // Resizes to new_size.

    virtual void

    do_resize(size_type new_size);

    typedef Trigger_Policy trigger_policy_base;

    typedef Size_Policy size_policy_base;

    size_type m_size;

  };

#include <ext/pb_ds/detail/resize_policy/hash_standard_resize_policy_imp.hpp>

#undef PB_DS_CLASS_T_DEC

#undef PB_DS_CLASS_C_DEC

} // namespace __gnu_pbds

#endif