// -*- C++ -*-

// Copyright (C) 2007 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.

/** @file parallel/algobase.h
 *  @brief Parallel STL function calls corresponding to the
 *  stl_algobase.h header.  The functions defined here mainly do case
 *  switches and call the actual parallelized versions in other files.
 *  Inlining policy: Functions that basically only contain one
 *  function call, are declared inline.
 *  This file is a GNU parallel extension to the Standard C++ Library.
 */

// Written by Johannes Singler and Felix Putze.

#ifndef _GLIBCXX_PARALLEL_ALGOBASE_H
#define _GLIBCXX_PARALLEL_ALGOBASE_H 1

#include <parallel/algorithmfwd.h>
#include <bits/stl_algobase.h>
#include <parallel/base.h>
#include <parallel/tags.h>
#include <parallel/settings.h>
#include <parallel/find.h>
#include <parallel/find_selectors.h>
#include <parallel/for_each.h>
#include <parallel/for_each_selectors.h>

namespace std
{
namespace __parallel
{
  // Sequential fallback
  template<typename InputIterator1, typename InputIterator2>
  inline bool
  equal(InputIterator1 begin1, InputIterator1 end1, InputIterator2 begin2, 
	__gnu_parallel::sequential_tag)
  { return _GLIBCXX_STD_P::equal(begin1, end1, begin2); }

  // Sequential fallback
  template<typename InputIterator1, typename InputIterator2, typename Predicate>
  inline bool
  equal(InputIterator1 begin1, InputIterator1 end1, InputIterator2 begin2, 
	Predicate pred, __gnu_parallel::sequential_tag)
  { return _GLIBCXX_STD_P::equal(begin1, end1, begin2, pred); }

  // Public interface
  template<typename InputIterator1, typename InputIterator2>
  inline bool
  equal(InputIterator1 begin1, InputIterator1 end1, InputIterator2 begin2)
  { return mismatch(begin1, end1, begin2).first == end1; }

  // Public interface
  template<typename InputIterator1, typename InputIterator2, typename Predicate>
  inline bool
  equal(InputIterator1 begin1, InputIterator1 end1, InputIterator2 begin2, 
	Predicate pred)
  { return mismatch(begin1, end1, begin2, pred).first == end1; }

  // NB: lexicographical_compare equires mismatch.

  // Sequential fallback
  template<typename InputIterator1, typename InputIterator2>
  inline pair<InputIterator1, InputIterator2>
  mismatch(InputIterator1 begin1, InputIterator1 end1, InputIterator2 begin2, 
	   __gnu_parallel::sequential_tag)
  { return _GLIBCXX_STD_P::mismatch(begin1, end1, begin2); }

  // Sequential fallback
  template<typename InputIterator1, typename InputIterator2, typename Predicate>
  inline pair<InputIterator1, InputIterator2>
  mismatch(InputIterator1 begin1, InputIterator1 end1, InputIterator2 begin2, 
	   Predicate pred, __gnu_parallel::sequential_tag)
  { return _GLIBCXX_STD_P::mismatch(begin1, end1, begin2, pred); }

  // Sequential fallback for input iterator case
  template<typename InputIterator1, typename InputIterator2, typename Predicate, typename IteratorTag1, typename IteratorTag2>
  inline pair<InputIterator1, InputIterator2>
  mismatch_switch(InputIterator1 begin1, InputIterator1 end1, 
		  InputIterator2 begin2, Predicate pred, IteratorTag1, 
		  IteratorTag2)
  { return _GLIBCXX_STD_P::mismatch(begin1, end1, begin2, pred); }

  // Parallel mismatch for random access iterators
  template<typename RandomAccessIterator1, typename RandomAccessIterator2, typename Predicate>
  pair<RandomAccessIterator1, RandomAccessIterator2>
  mismatch_switch(RandomAccessIterator1 begin1, RandomAccessIterator1 end1, 
		  RandomAccessIterator2 begin2, Predicate pred, 
		  random_access_iterator_tag, random_access_iterator_tag)
  {
    if (_GLIBCXX_PARALLEL_CONDITION(true))
      {
	RandomAccessIterator1 res = __gnu_parallel::find_template(begin1, end1, begin2, pred, __gnu_parallel::mismatch_selector()).first;
	return make_pair(res , begin2 + (res - begin1));
      }
    else
      return _GLIBCXX_STD_P::mismatch(begin1, end1, begin2, pred);
  }

  // Public interface
  template<typename InputIterator1, typename InputIterator2>
  inline pair<InputIterator1, InputIterator2>
  mismatch(InputIterator1 begin1, InputIterator1 end1, InputIterator2 begin2)
  {
    typedef std::iterator_traits<InputIterator1> iterator1_traits;
    typedef std::iterator_traits<InputIterator2> iterator2_traits;
    typedef typename iterator1_traits::value_type value1_type;
    typedef typename iterator2_traits::value_type value2_type;
    typedef typename iterator1_traits::iterator_category iterator1_category;
    typedef typename iterator2_traits::iterator_category iterator2_category;

    typedef __gnu_parallel::equal_to<value1_type, value2_type> equal_to_type;

    return mismatch_switch(begin1, end1, begin2, equal_to_type(),
			   iterator1_category(), iterator2_category());
  }

  // Public interface
  template<typename InputIterator1, typename InputIterator2, typename Predicate>
  inline pair<InputIterator1, InputIterator2>
  mismatch(InputIterator1 begin1, InputIterator1 end1, InputIterator2 begin2,
	   Predicate pred)
  {
    typedef std::iterator_traits<InputIterator1> iterator1_traits;
    typedef std::iterator_traits<InputIterator2> iterator2_traits;
    typedef typename iterator1_traits::iterator_category iterator1_category;
    typedef typename iterator2_traits::iterator_category iterator2_category;

    return mismatch_switch(begin1, end1, begin2, pred, iterator1_category(), 
			   iterator2_category());
  }

  // Sequential fallback
  template<typename InputIterator1, typename InputIterator2>
  inline bool
  lexicographical_compare(InputIterator1 begin1, InputIterator1 end1, 
			  InputIterator2 begin2, InputIterator2 end2, 
			  __gnu_parallel::sequential_tag)
  {
    return _GLIBCXX_STD_P::lexicographical_compare(begin1, end1, begin2, end2);
  }

  // Sequential fallback
  template<typename InputIterator1, typename InputIterator2, typename Predicate>
  inline bool
  lexicographical_compare(InputIterator1 begin1, InputIterator1 end1, 
			  InputIterator2 begin2, InputIterator2 end2, 
			  Predicate pred, __gnu_parallel::sequential_tag)
  {
    return _GLIBCXX_STD_P::lexicographical_compare(begin1, end1, 
						   begin2, end2, pred);
  }

  // Sequential fallback for input iterator case
  template<typename InputIterator1, typename InputIterator2, typename Predicate, typename IteratorTag1, typename IteratorTag2>
  inline bool
  lexicographical_compare_switch(InputIterator1 begin1, InputIterator1 end1, 
				 InputIterator2 begin2, InputIterator2 end2, 
				 Predicate pred, IteratorTag1, IteratorTag2)
  {
    return _GLIBCXX_STD_P::lexicographical_compare(begin1, end1, 
						   begin2, end2, pred);
  }

  // Parallel lexicographical_compare for random access iterators
  // Limitation: Both valuetypes must be the same
  template<typename RandomAccessIterator1, typename RandomAccessIterator2, typename Predicate>
  bool
  lexicographical_compare_switch(RandomAccessIterator1 begin1, 
				 RandomAccessIterator1 end1, 
				 RandomAccessIterator2 begin2, 
				 RandomAccessIterator2 end2, Predicate pred, 
				 random_access_iterator_tag, 
				 random_access_iterator_tag)
  {
    if (_GLIBCXX_PARALLEL_CONDITION(true))
      {
	typedef iterator_traits<RandomAccessIterator1> traits1_type;
	typedef typename traits1_type::value_type value1_type;

	typedef iterator_traits<RandomAccessIterator2> traits2_type;
	typedef typename traits2_type::value_type value2_type;
	
	typedef __gnu_parallel::equal_from_less<Predicate, value1_type, value2_type> equal_type;

	// Longer sequence in first place.
	if ((end1 - begin1) < (end2 - begin2))
	  {
	    typedef pair<RandomAccessIterator1, RandomAccessIterator2> pair_type;
	    pair_type mm = mismatch_switch(begin1, end1, begin2, 
					   equal_type(pred), 
					   random_access_iterator_tag(), 
					   random_access_iterator_tag());

	    // Less because shorter.
	    const bool lbs = mm.first == end1;

	    // Less because differing elements less.
	    const bool lbdel = pred(*mm.first, *mm.second);

	    return lbs || lbdel;
	  }
	else
	  {
	    typedef pair<RandomAccessIterator2, RandomAccessIterator1> pair_type;
	    pair_type mm = mismatch_switch(begin2, end2, begin1, 
					   equal_type(pred), 
					   random_access_iterator_tag(), 
					   random_access_iterator_tag());

	    // Less because shorter.
	    const bool lbs = mm.first != end2;

	    // Less because differing element less.
	    const bool lbdel = pred(*mm.second, *mm.first);

	    return lbs && lbdel;
	  }
      }
    else
      return _GLIBCXX_STD_P::lexicographical_compare(begin1, end1, begin2, end2, pred);
  }

  // Public interface
  template<typename InputIterator1, typename InputIterator2>
  inline bool
  lexicographical_compare(InputIterator1 begin1, InputIterator1 end1, InputIterator2 begin2, InputIterator2 end2)
  {
    typedef iterator_traits<InputIterator1> traits1_type;
    typedef typename traits1_type::value_type value1_type;
    typedef typename traits1_type::iterator_category iterator1_category;
    
    typedef iterator_traits<InputIterator2> traits2_type;
    typedef typename traits2_type::value_type value2_type;
    typedef typename traits2_type::iterator_category iterator2_category;
    typedef __gnu_parallel::less<value1_type, value2_type> less_type;

    return lexicographical_compare_switch(begin1, end1, begin2, end2, 
					  less_type(), iterator1_category(), 
					  iterator2_category());
  }

  // Public interface
  template<typename InputIterator1, typename InputIterator2, typename Predicate>
  inline bool
  lexicographical_compare(InputIterator1 begin1, InputIterator1 end1, InputIterator2 begin2, InputIterator2 end2, Predicate pred)
  {
    typedef iterator_traits<InputIterator1> traits1_type;
    typedef typename traits1_type::iterator_category iterator1_category;
    
    typedef iterator_traits<InputIterator2> traits2_type;
    typedef typename traits2_type::iterator_category iterator2_category;

    return lexicographical_compare_switch(begin1, end1, begin2, end2, pred, 
					  iterator1_category(), 
					  iterator2_category());
  }
} // end namespace
} // end namespace

#endif /* _GLIBCXX_ALGOBASE_H */
