mirror of
https://github.com/triqs/dft_tools
synced 2024-11-01 03:33:50 +01:00
97 lines
4.2 KiB
C++
97 lines
4.2 KiB
C++
// (C) Copyright 2008-10 Lukas Gamper <gamperl -at- gmail.com>
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// Brigitte Surer <surerb -at- phys.ethz.ch>
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// Bela Bauer <bauerb -at- phys.ethz.ch>
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//
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// downgraded by O. Parcollet for compilation with icc11 & boost 1.45
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//
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// Use, modification, and distribution are subject to the Boost Software
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// License, Version 1.0. (See at <http://www.boost.org/LICENSE_1_0.txt>.)
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#include <vector>
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#include <algorithm>
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#include <boost/function.hpp>
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#include <boost/ref.hpp>
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#include <boost/shared_ptr.hpp>
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#include <boost/make_shared.hpp>
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#include <boost/lambda/lambda.hpp>
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#include <boost/lambda/bind.hpp>
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#include <boost/lambda/construct.hpp>
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#include <boost/lambda/exceptions.hpp>
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namespace boost{
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template<typename R> class generator {
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public:
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static std::size_t const buffer_size = 1000;
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template<typename Generator> generator(Generator const & gen, std::size_t size = buffer_size)
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:
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buf(make_shared<buffer>(gen, size))
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, cur(buf->cur)
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, end(buf->end())
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{}
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inline R const operator()() {
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if (cur == end)
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buf->fill();
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return *cur++;
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}
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inline R const preview() {
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if (cur == end)
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buf->fill();
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return *cur;
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}
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generator(generator<R> const & rhs)
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:
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buf(new buffer (*rhs.buf))
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, cur(buf->cur)
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, end(buf->end())
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{}
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generator<R> & operator=(generator<R> rhs) {
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swap(*this, rhs);
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return *this;
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}
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private:
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class buffer: public std::vector<R> {
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public:
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friend class generator<R>;
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template<typename Generator> buffer(Generator const & gen, std::size_t size)
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: std::vector<R>(size)
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, engine(make_shared<Generator>(gen))
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, cur(this->end())
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, fill_helper(lambda::bind(std::generate<typename buffer::iterator, Generator &>, lambda::_1, lambda::_2, ref(*reinterpret_cast<Generator *>(engine.get()))))
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, clone(lambda::bind(buffer::template type_keeper<Generator>, lambda::_1, lambda::_2))
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{}
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template<typename Generator> buffer(reference_wrapper<Generator> gen, std::size_t size)
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: std::vector<R>(size)
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, cur(this->end())
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, fill_helper(lambda::bind(std::generate<typename buffer::iterator, Generator &>, lambda::_1, lambda::_2, gen))
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{}
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buffer(buffer const & rhs)
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: std::vector<R>(rhs)
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, cur(this->begin() + (rhs.cur - rhs.begin()))
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, fill_helper(rhs.fill_helper)
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, clone(rhs.clone)
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{
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if (rhs.engine)
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clone(*this, rhs);
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}
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inline void fill() {
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fill_helper(this->begin(), this->end());
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cur = this->begin();
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}
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private:
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template<typename Generator> static void type_keeper(buffer & lhs, buffer const & rhs) {
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lhs.engine = make_shared<Generator>(*reinterpret_cast<Generator *>(rhs.engine.get()));
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lhs.fill_helper = lambda::bind(std::generate<typename buffer::iterator, Generator &>, lambda::_1, lambda::_2, ref(*reinterpret_cast<Generator *>(lhs.engine.get())));
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}
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shared_ptr<void> engine;
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typename std::vector<R>::const_iterator cur;
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function<void(typename std::vector<R>::iterator, typename std::vector<R>::iterator)> fill_helper;
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function<void(buffer &, buffer const &)> clone;
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};
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shared_ptr<buffer> buf;
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typename buffer::const_iterator & cur;
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typename buffer::const_iterator end;
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};
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}
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