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| author | Tobias Markmann <tm@ayena.de> | 2017-02-17 17:15:41 (GMT) |
|---|---|---|
| committer | Tobias Markmann <tm@ayena.de> | 2017-02-22 10:54:22 (GMT) |
| commit | eea861301be0bf3e3f5db6cfc3cada38d133fef2 (patch) | |
| tree | 3c2aa07ce3724a73ce2124832bee6b8c7884c9df /3rdParty/Boost/src/boost/multi_index/detail/index_saver.hpp | |
| parent | 80801aaeba2d29e3a375a01d782cf081e778dfaf (diff) | |
| download | swift-eea861301be0bf3e3f5db6cfc3cada38d133fef2.zip swift-eea861301be0bf3e3f5db6cfc3cada38d133fef2.tar.bz2 | |
Add LRUCache utility class to Swiften
This implements a simple lookup cache with least recently used
replacement strategy.
This also adds Boost.MultiIndex from version 1.56 to 3rdParty.
Test-Information:
Added some unit tests for LRUCache, which pass on macOS 10.12.3
with clang-5.0
Change-Id: I0567945b1197d3fe786bf9d82fdb5e755743b975
Diffstat (limited to '3rdParty/Boost/src/boost/multi_index/detail/index_saver.hpp')
| -rw-r--r-- | 3rdParty/Boost/src/boost/multi_index/detail/index_saver.hpp | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/3rdParty/Boost/src/boost/multi_index/detail/index_saver.hpp b/3rdParty/Boost/src/boost/multi_index/detail/index_saver.hpp new file mode 100644 index 0000000..ae09d4e --- /dev/null +++ b/3rdParty/Boost/src/boost/multi_index/detail/index_saver.hpp @@ -0,0 +1,135 @@ +/* Copyright 2003-2013 Joaquin M Lopez Munoz. + * 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_INDEX_SAVER_HPP +#define BOOST_MULTI_INDEX_DETAIL_INDEX_SAVER_HPP + +#if defined(_MSC_VER) +#pragma once +#endif + +#include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */ +#include <boost/multi_index/detail/index_matcher.hpp> +#include <boost/noncopyable.hpp> +#include <boost/serialization/nvp.hpp> +#include <cstddef> + +namespace boost{ + +namespace multi_index{ + +namespace detail{ + +/* index_saver accepts a base sequence of previously saved elements + * and saves a possibly reordered subsequence in an efficient manner, + * serializing only the information needed to rearrange the subsequence + * based on the original order of the base. + * multi_index_container is in charge of supplying the info about the + * base sequence, and each index can subsequently save itself using the + * const interface of index_saver. + */ + +template<typename Node,typename Allocator> +class index_saver:private noncopyable +{ +public: + index_saver(const Allocator& al,std::size_t size):alg(al,size){} + + template<class Archive> + void add(Node* node,Archive& ar,const unsigned int) + { + ar<<serialization::make_nvp("position",*node); + alg.add(node); + } + + template<class Archive> + void add_track(Node* node,Archive& ar,const unsigned int) + { + ar<<serialization::make_nvp("position",*node); + } + + template<typename IndexIterator,class Archive> + void save( + IndexIterator first,IndexIterator last,Archive& ar, + const unsigned int)const + { + /* calculate ordered positions */ + + alg.execute(first,last); + + /* Given a consecutive subsequence of displaced elements + * x1,...,xn, the following information is serialized: + * + * p0,p1,...,pn,0 + * + * where pi is a pointer to xi and p0 is a pointer to the element + * preceding x1. Crealy, from this information is possible to + * restore the original order on loading time. If x1 is the first + * element in the sequence, the following is serialized instead: + * + * p1,p1,...,pn,0 + * + * For each subsequence of n elements, n+2 pointers are serialized. + * An optimization policy is applied: consider for instance the + * sequence + * + * a,B,c,D + * + * where B and D are displaced, but c is in its correct position. + * Applying the schema described above we would serialize 6 pointers: + * + * p(a),p(B),0 + * p(c),p(D),0 + * + * but this can be reduced to 5 pointers by treating c as a displaced + * element: + * + * p(a),p(B),p(c),p(D),0 + */ + + std::size_t last_saved=3; /* distance to last pointer saved */ + for(IndexIterator it=first,prev=first;it!=last;prev=it++,++last_saved){ + if(!alg.is_ordered(get_node(it))){ + if(last_saved>1)save_node(get_node(prev),ar); + save_node(get_node(it),ar); + last_saved=0; + } + else if(last_saved==2)save_node(null_node(),ar); + } + if(last_saved<=2)save_node(null_node(),ar); + + /* marks the end of the serialization info for [first,last) */ + + save_node(null_node(),ar); + } + +private: + template<typename IndexIterator> + static Node* get_node(IndexIterator it) + { + return it.get_node(); + } + + static Node* null_node(){return 0;} + + template<typename Archive> + static void save_node(Node* node,Archive& ar) + { + ar<<serialization::make_nvp("pointer",node); + } + + index_matcher::algorithm<Node,Allocator> alg; +}; + +} /* namespace multi_index::detail */ + +} /* namespace multi_index */ + +} /* namespace boost */ + +#endif |