X-Git-Url: http://g0dil.de/git?a=blobdiff_plain;f=boost_ext%2Fboost%2Fmulti_index%2Fdetail%2Frnd_index_loader.hpp;fp=boost_ext%2Fboost%2Fmulti_index%2Fdetail%2Frnd_index_loader.hpp;h=69ec8b73abbfd1b952c16d625021e9e4e184422e;hb=4123b4fe58a7fd4659fa01476581690b47c83600;hp=0000000000000000000000000000000000000000;hpb=79564b90f6c9f7cd0bc5b11a6146bb7067b11a75;p=senf.git diff --git a/boost_ext/boost/multi_index/detail/rnd_index_loader.hpp b/boost_ext/boost/multi_index/detail/rnd_index_loader.hpp new file mode 100644 index 0000000..69ec8b7 --- /dev/null +++ b/boost_ext/boost/multi_index/detail/rnd_index_loader.hpp @@ -0,0 +1,176 @@ +/* Copyright 2003-2007 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_RND_INDEX_LOADER_HPP +#define BOOST_MULTI_INDEX_DETAIL_RND_INDEX_LOADER_HPP + +#if defined(_MSC_VER)&&(_MSC_VER>=1200) +#pragma once +#endif + +#include /* keep it first to prevent nasty warns in MSVC */ +#include +#include +#include +#include +#include +#include +#include + +namespace boost{ + +namespace multi_index{ + +namespace detail{ + +/* This class implements a serialization rearranger for random access + * indices. In order to achieve O(n) performance, the following strategy + * is followed: the nodes of the index are handled as if in a bidirectional + * list, where the next pointers are stored in the original + * random_access_index_ptr_array and the prev pointers are stored in + * an auxiliary array. Rearranging of nodes in such a bidirectional list + * is constant time. Once all the arrangements are performed (on destruction + * time) the list is traversed in reverse order and + * pointers are swapped and set accordingly so that they recover its + * original semantics ( *(node->up())==node ) while retaining the + * new order. + */ + +template +class random_access_index_loader_base:private noncopyable +{ +protected: + typedef typename prevent_eti< + Allocator, + random_access_index_node_impl< + typename boost::detail::allocator::rebind_to< + Allocator, + void + >::type + > + >::type node_impl_type; + typedef typename node_impl_type::pointer node_impl_pointer; + typedef random_access_index_ptr_array ptr_array; + + random_access_index_loader_base(const Allocator& al_,ptr_array& ptrs_): + al(al_), + ptrs(ptrs_), + header(*ptrs.end()), + prev_spc(al,0), + preprocessed(false) + {} + + ~random_access_index_loader_base() + { + if(preprocessed) + { + node_impl_pointer n=header; + next(n)=n; + + for(std::size_t i=ptrs.size();i--;){ + n=prev(n); + std::size_t d=position(n); + if(d!=i){ + node_impl_pointer m=prev(next_at(i)); + std::swap(m->up(),n->up()); + next_at(d)=next_at(i); + std::swap(prev_at(d),prev_at(i)); + } + next(n)=n; + } + } + } + + void rearrange(node_impl_pointer position,node_impl_pointer x) + { + preprocess(); /* only incur this penalty if rearrange() is ever called */ + if(position==node_impl_pointer(0))position=header; + next(prev(x))=next(x); + prev(next(x))=prev(x); + prev(x)=position; + next(x)=next(position); + next(prev(x))=prev(next(x))=x; + } + +private: + void preprocess() + { + if(!preprocessed){ + /* get space for the auxiliary prev array */ + auto_space tmp(al,ptrs.size()+1); + prev_spc.swap(tmp); + + /* prev_spc elements point to the prev nodes */ + std::rotate_copy( + &*ptrs.begin(),&*ptrs.end(),&*ptrs.end()+1,&*prev_spc.data()); + + /* ptrs elements point to the next nodes */ + std::rotate(&*ptrs.begin(),&*ptrs.begin()+1,&*ptrs.end()+1); + + preprocessed=true; + } + } + + std::size_t position(node_impl_pointer x)const + { + return (std::size_t)(x->up()-ptrs.begin()); + } + + node_impl_pointer& next_at(std::size_t n)const + { + return *ptrs.at(n); + } + + node_impl_pointer& prev_at(std::size_t n)const + { + return *(prev_spc.data()+n); + } + + node_impl_pointer& next(node_impl_pointer x)const + { + return *(x->up()); + } + + node_impl_pointer& prev(node_impl_pointer x)const + { + return prev_at(position(x)); + } + + Allocator al; + ptr_array& ptrs; + node_impl_pointer header; + auto_space prev_spc; + bool preprocessed; +}; + +template +class random_access_index_loader: + private random_access_index_loader_base +{ + typedef random_access_index_loader_base super; + typedef typename super::node_impl_pointer node_impl_pointer; + typedef typename super::ptr_array ptr_array; + +public: + random_access_index_loader(const Allocator& al_,ptr_array& ptrs_): + super(al_,ptrs_) + {} + + void rearrange(Node* position,Node *x) + { + super::rearrange(position?position->impl():node_impl_pointer(0),x->impl()); + } +}; + +} /* namespace multi_index::detail */ + +} /* namespace multi_index */ + +} /* namespace boost */ + +#endif