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// -*- C++ -*-

// Copyright (C) 2007, 2008, 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/>.

/** @file parallel/find_selectors.h

 *  @brief _Function objects representing different tasks to be plugged

 *  into the parallel find algorithm.

 *  This file is a GNU parallel extension to the Standard C++ Library.

 */

// Written by Felix Putze.

#ifndef _GLIBCXX_PARALLEL_FIND_SELECTORS_H

#define _GLIBCXX_PARALLEL_FIND_SELECTORS_H 1

#include <parallel/tags.h>

#include <parallel/basic_iterator.h>

#include <bits/stl_pair.h>

namespace __gnu_parallel

{

  /** @brief Base class of all __gnu_parallel::__find_template selectors. */

  struct __generic_find_selector

  { };

  /**

   *  @brief Test predicate on a single element, used for std::find()

   *  and std::find_if ().

   */

  struct __find_if_selector : public __generic_find_selector

  {

    /** @brief Test on one position.

     * @param __i1 _Iterator on first sequence.

     * @param __i2 _Iterator on second sequence (unused).

     * @param __pred Find predicate.

     */

    template<typename _RAIter1, typename _RAIter2,

             typename _Pred>

      bool

      operator()(_RAIter1 __i1, _RAIter2 __i2, _Pred __pred)

      { return __pred(*__i1); }

    /** @brief Corresponding sequential algorithm on a sequence.

     *  @param __begin1 Begin iterator of first sequence.

     *  @param __end1 End iterator of first sequence.

     *  @param __begin2 Begin iterator of second sequence.

     *  @param __pred Find predicate.

     */

    template<typename _RAIter1, typename _RAIter2,

             typename _Pred>

      std::pair<_RAIter1, _RAIter2>

      _M_sequential_algorithm(_RAIter1 __begin1,

                           _RAIter1 __end1,

                           _RAIter2 __begin2, _Pred __pred)

      { return std::make_pair(find_if(__begin1, __end1, __pred,

                                      sequential_tag()), __begin2); }

  };

  /** @brief Test predicate on two adjacent elements. */

  struct __adjacent_find_selector : public __generic_find_selector

  {

    /** @brief Test on one position.

     *  @param __i1 _Iterator on first sequence.

     *  @param __i2 _Iterator on second sequence (unused).

     *  @param __pred Find predicate.

     */

    template<typename _RAIter1, typename _RAIter2,

             typename _Pred>

      bool

      operator()(_RAIter1 __i1, _RAIter2 __i2, _Pred __pred)

      {

        // Passed end iterator is one short.

        return __pred(*__i1, *(__i1 + 1));

      }

    /** @brief Corresponding sequential algorithm on a sequence.

     *  @param __begin1 Begin iterator of first sequence.

     *  @param __end1 End iterator of first sequence.

     *  @param __begin2 Begin iterator of second sequence.

     *  @param __pred Find predicate.

     */

    template<typename _RAIter1, typename _RAIter2,

             typename _Pred>

      std::pair<_RAIter1, _RAIter2>

      _M_sequential_algorithm(_RAIter1 __begin1,

                              _RAIter1 __end1,

                              _RAIter2 __begin2, _Pred __pred)

      {

        // Passed end iterator is one short.

        _RAIter1 __spot = adjacent_find(__begin1, __end1 + 1,

                                        __pred, sequential_tag());

        if (__spot == (__end1 + 1))

          __spot = __end1;

        return std::make_pair(__spot, __begin2);

      }

  };

  /** @brief Test inverted predicate on a single element. */

  struct __mismatch_selector : public __generic_find_selector

  {

    /**

     *  @brief Test on one position.

     *  @param __i1 _Iterator on first sequence.

     *  @param __i2 _Iterator on second sequence (unused).

     *  @param __pred Find predicate.

     */

    template<typename _RAIter1, typename _RAIter2,

             typename _Pred>

      bool

      operator()(_RAIter1 __i1, _RAIter2 __i2, _Pred __pred)

      { return !__pred(*__i1, *__i2); }

    /**

     *  @brief Corresponding sequential algorithm on a sequence.

     *  @param __begin1 Begin iterator of first sequence.

     *  @param __end1 End iterator of first sequence.

     *  @param __begin2 Begin iterator of second sequence.

     *  @param __pred Find predicate.

     */

    template<typename _RAIter1, typename _RAIter2,

             typename _Pred>

      std::pair<_RAIter1, _RAIter2>

      _M_sequential_algorithm(_RAIter1 __begin1,

                              _RAIter1 __end1,

                              _RAIter2 __begin2, _Pred __pred)

      { return mismatch(__begin1, __end1, __begin2,

                        __pred, sequential_tag()); }

  };

  /** @brief Test predicate on several elements. */

  template<typename _FIterator>

    struct __find_first_of_selector : public __generic_find_selector

    {

      _FIterator _M_begin;

      _FIterator _M_end;

      explicit __find_first_of_selector(_FIterator __begin,

                                        _FIterator __end)

      : _M_begin(__begin), _M_end(__end) { }

      /** @brief Test on one position.

       *  @param __i1 _Iterator on first sequence.

       *  @param __i2 _Iterator on second sequence (unused).

       *  @param __pred Find predicate. */

      template<typename _RAIter1, typename _RAIter2,

               typename _Pred>

        bool

        operator()(_RAIter1 __i1, _RAIter2 __i2, _Pred __pred)

        {

          for (_FIterator __pos_in_candidates = _M_begin;

               __pos_in_candidates != _M_end; ++__pos_in_candidates)

            if (__pred(*__i1, *__pos_in_candidates))

              return true;

          return false;

        }

      /** @brief Corresponding sequential algorithm on a sequence.

       *  @param __begin1 Begin iterator of first sequence.

       *  @param __end1 End iterator of first sequence.

       *  @param __begin2 Begin iterator of second sequence.

       *  @param __pred Find predicate. */

      template<typename _RAIter1, typename _RAIter2,

               typename _Pred>

        std::pair<_RAIter1, _RAIter2>

        _M_sequential_algorithm(_RAIter1 __begin1,

                                _RAIter1 __end1,

                                _RAIter2 __begin2, _Pred __pred)

        {

          return std::make_pair(find_first_of(__begin1, __end1,

                                              _M_begin, _M_end, __pred,

                                              sequential_tag()), __begin2);

        }

     };

}

#endif /* _GLIBCXX_PARALLEL_FIND_SELECTORS_H */