/* Copyright 2003-2004 Joaquín M López Muñoz.
 * Distributed under the Boost Software License, Version 1.0.
 * (See accompanying file LICENSE_1_0.txt or copy at
 * http://www.boost.org/LICENSE_1_0.txt)
 *
 * See http://www.boost.org/libs/multi_index for library home page.
 */

#ifndef BOOST_MULTI_INDEX_DETAIL_SEQ_INDEX_OPS_HPP
#define BOOST_MULTI_INDEX_DETAIL_SEQ_INDEX_OPS_HPP

#include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
#include <boost/aligned_storage.hpp>
#include <boost/detail/no_exceptions_support.hpp>
#include <boost/multi_index/detail/seq_index_node.hpp>
#include <boost/limits.hpp>
#include <cstddef>

namespace boost{

namespace multi_index{

namespace detail{

/* Common code for sequenced_index memfuns having templatized and
 * non-templatized versions.
 */

template <typename SequencedIndex,typename Predicate>
void sequenced_index_remove(SequencedIndex& x,Predicate pred)
{
  typedef typename SequencedIndex::iterator iterator;
  iterator first=x.begin(),last=x.end();
  while(first!=last){
    if(pred(*first))x.erase(first++);
    else ++first;
  }
}

template <typename SequencedIndex,class BinaryPredicate>
void sequenced_index_unique(SequencedIndex& x,BinaryPredicate binary_pred)
{
  typedef typename SequencedIndex::iterator iterator;
  iterator first=x.begin();
  iterator last=x.end();
  if(first!=last){
    for(iterator middle=first;++middle!=last;middle=first){
      if(binary_pred(*middle,*first))x.erase(middle);
      else first=middle;
    }
  }
}

template <typename SequencedIndex,typename Compare>
void sequenced_index_merge(SequencedIndex& x,SequencedIndex& y,Compare comp)
{
  typedef typename SequencedIndex::iterator iterator;
  if(x!=y){
    iterator first0=x.begin(),last0=x.end();
    iterator first1=y.begin(),last1=y.end();
    while(first0!=last0&&first1!=last1){
      if(comp(*first1,*first0))x.splice(first0,y,first1++);
      else ++first0;
    }
    x.splice(last0,y,first1,last1);
  }
}

/* sorting  */

/* auxiliary stuff */

template<typename Node,typename Compare>
void sequenced_index_collate(
  sequenced_index_node_impl* x,sequenced_index_node_impl* y,Compare comp
  BOOST_APPEND_EXPLICIT_TEMPLATE_TYPE(Node))
{
  sequenced_index_node_impl* first0=x->next();
  sequenced_index_node_impl* last0=x;
  sequenced_index_node_impl* first1=y->next();
  sequenced_index_node_impl* last1=y;
  while(first0!=last0&&first1!=last1){
    if(comp(Node::from_impl(first1)->value,Node::from_impl(first0)->value)){
      sequenced_index_node_impl* tmp=first1->next();
      sequenced_index_node_impl::relink(first0,first1);
      first1=tmp;
    }
    else first0=first0->next();
  }
  sequenced_index_node_impl::relink(last0,first1,last1);
}

template<typename Node,typename Compare>
void sequenced_index_sort(Node* header,Compare comp)
{
  /* Musser's mergesort, see http://www.cs.rpi.edu/~musser/gp/List/lists1.html.
   * The implementation is a little convoluted: in the original code
   * counter elements and carry are std::lists: here we do not want
   * to use multi_index instead, so we do things at a lower level, managing
   * directly the internal node representation.
   * Incidentally, the implementations I've seen of this algorithm (SGI,
   * Dinkumware, STLPort) are not exception-safe: this is. Moreover, we do not
   * use any dynamic storage.
   */

  if(header->next()==header->impl()||
     header->next()->next()==header->impl())return;

  BOOST_STATIC_CONSTANT(
    std::size_t,
    max_fill=(std::size_t)std::numeric_limits<std::size_t>::digits+1);

  aligned_storage<
    sizeof(sequenced_index_node_impl)>      carry_spc;
  sequenced_index_node_impl&                carry=
    *static_cast<sequenced_index_node_impl*>(carry_spc.address());
  aligned_storage<
    sizeof(
      sequenced_index_node_impl[max_fill])> counter_spc;
  sequenced_index_node_impl*                counter=
    static_cast<sequenced_index_node_impl*>(counter_spc.address());
  std::size_t                               fill=0;

  carry.prior()=carry.next()=&carry;
  counter[0].prior()=counter[0].next()=&counter[0];

  BOOST_TRY{
    while(header->next()!=header->impl()){
      sequenced_index_node_impl::relink(carry.next(),header->next());
      std::size_t i=0;
      while(i<fill&&counter[i].next()!=&counter[i]){
        sequenced_index_collate<Node>(&carry,&counter[i++],comp);
      }
      sequenced_index_node_impl::swap(&carry,&counter[i]);
      if(i==fill){
        ++fill;
        counter[fill].prior()=counter[fill].next()=&counter[fill];
      }
    }

    for(std::size_t i=1;i<fill;++i){
      sequenced_index_collate<Node>(&counter[i],&counter[i-1],comp);
    }
    sequenced_index_node_impl::swap(header->impl(),&counter[fill-1]);
  }
  BOOST_CATCH(...)
  {
    sequenced_index_node_impl::relink(header->impl(),carry.next(),&carry);
    for(std::size_t i=0;i<=fill;++i){
      sequenced_index_node_impl::relink(
        header->impl(),counter[i].next(),&counter[i]);
    }
    BOOST_RETHROW;
  }
  BOOST_CATCH_END
}

} /* namespace multi_index::detail */

} /* namespace multi_index */

} /* namespace boost */

#endif
