epoc32/include/stdapis/boost/multi_index/detail/hash_index_args.hpp
author William Roberts <williamr@symbian.org>
Wed, 31 Mar 2010 12:27:01 +0100
branchSymbian2
changeset 3 e1b950c65cb4
permissions -rw-r--r--
Attempt to represent the S^2->S^3 header reorganisation as a series of "hg rename" operations
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/* Copyright 2003-2005 Joaquín M López Muñoz.
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 * Distributed under the Boost Software License, Version 1.0.
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 * (See accompanying file LICENSE_1_0.txt or copy at
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 * http://www.boost.org/LICENSE_1_0.txt)
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 *
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 * See http://www.boost.org/libs/multi_index for library home page.
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 */
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#ifndef BOOST_MULTI_INDEX_DETAIL_HASH_INDEX_ARGS_HPP
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#define BOOST_MULTI_INDEX_DETAIL_HASH_INDEX_ARGS_HPP
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#if defined(_MSC_VER)&&(_MSC_VER>=1200)
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#pragma once
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#endif
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#include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
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#include <boost/functional/hash/hash.hpp>
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#include <boost/mpl/aux_/na.hpp>
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#include <boost/mpl/eval_if.hpp>
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#include <boost/mpl/identity.hpp>
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#include <boost/mpl/if.hpp>
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#include <boost/multi_index/tag.hpp>
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#include <boost/static_assert.hpp>
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#include <boost/type_traits/is_same.hpp>
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#include <functional>
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namespace boost{
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template<class T> struct hash; /* fwd decl. */
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namespace multi_index{
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namespace detail{
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/* Hashed index specifiers can be instantiated in two forms:
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 *
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 *   (hashed_unique|hashed_non_unique)<
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 *     KeyFromValue,
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 *     Hash=boost::hash<KeyFromValue::result_type>,
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 *     Pred=std::equal_to<KeyFromValue::result_type> >
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 *   (hashed_unique|hashed_non_unique)<
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 *     TagList,
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 *     KeyFromValue,
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 *     Hash=boost::hash<KeyFromValue::result_type>,
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 *     Pred=std::equal_to<KeyFromValue::result_type> >
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 *
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 * hashed_index_args implements the machinery to accept this
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 * argument-dependent polymorphism.
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 */
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template<typename KeyFromValue>
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struct index_args_default_hash
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{
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  typedef ::boost::hash<typename KeyFromValue::result_type> type;
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};
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template<typename KeyFromValue>
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struct index_args_default_pred
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{
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  typedef std::equal_to<typename KeyFromValue::result_type> type;
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};
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template<typename Arg1,typename Arg2,typename Arg3,typename Arg4>
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struct hashed_index_args
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{
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  typedef is_tag<Arg1> full_form;
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  typedef typename mpl::if_<
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    full_form,
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    Arg1,
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    tag< > >::type                                   tag_list_type;
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  typedef typename mpl::if_<
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    full_form,
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    Arg2,
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    Arg1>::type                                      key_from_value_type;
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  typedef typename mpl::if_<
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    full_form,
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    Arg3,
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    Arg2>::type                                      supplied_hash_type;
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  typedef typename mpl::eval_if<
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    mpl::is_na<supplied_hash_type>,
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    index_args_default_hash<key_from_value_type>,
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    mpl::identity<supplied_hash_type>
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  >::type                                            hash_type;
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  typedef typename mpl::if_<
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    full_form,
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    Arg4,
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    Arg3>::type                                      supplied_pred_type;
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  typedef typename mpl::eval_if<
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    mpl::is_na<supplied_pred_type>,
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    index_args_default_pred<key_from_value_type>,
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    mpl::identity<supplied_pred_type>
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  >::type                                            pred_type;
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  BOOST_STATIC_ASSERT(is_tag<tag_list_type>::value);
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  BOOST_STATIC_ASSERT(!mpl::is_na<key_from_value_type>::value);
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  BOOST_STATIC_ASSERT(!mpl::is_na<hash_type>::value);
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  BOOST_STATIC_ASSERT(!mpl::is_na<pred_type>::value);
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};
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} /* namespace multi_index::detail */
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} /* namespace multi_index */
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} /* namespace boost */
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#endif