//
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// Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot com)
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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// Official repository: https://github.com/boostorg/beast
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//
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#ifndef BOOST_BEAST_IMPL_BUFFERS_PREFIX_HPP
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#define BOOST_BEAST_IMPL_BUFFERS_PREFIX_HPP
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#include <boost/beast/core/buffer_traits.hpp>
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#include <boost/config/workaround.hpp>
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#include <algorithm>
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#include <cstdint>
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#include <iterator>
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#include <stdexcept>
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#include <type_traits>
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#include <utility>
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namespace boost {
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namespace beast {
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template<class Buffers>
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class buffers_prefix_view<Buffers>::const_iterator
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{
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friend class buffers_prefix_view<Buffers>;
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buffers_prefix_view const* b_ = nullptr;
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std::size_t remain_ = 0;
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iter_type it_{};
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public:
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#if BOOST_WORKAROUND(BOOST_MSVC, < 1910)
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using value_type = typename std::conditional<
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boost::is_convertible<typename
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std::iterator_traits<iter_type>::value_type,
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net::mutable_buffer>::value,
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net::mutable_buffer,
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net::const_buffer>::type;
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#else
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using value_type = buffers_type<Buffers>;
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#endif
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BOOST_STATIC_ASSERT(std::is_same<
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typename const_iterator::value_type,
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typename buffers_prefix_view::value_type>::value);
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using pointer = value_type const*;
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using reference = value_type;
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using difference_type = std::ptrdiff_t;
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using iterator_category =
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std::bidirectional_iterator_tag;
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const_iterator() = default;
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const_iterator(
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const_iterator const& other) = default;
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const_iterator& operator=(
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const_iterator const& other) = default;
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bool
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operator==(const_iterator const& other) const
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{
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return b_ == other.b_ && it_ == other.it_;
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}
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bool
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operator!=(const_iterator const& other) const
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{
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return !(*this == other);
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}
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reference
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operator*() const
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{
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value_type v(*it_);
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if(remain_ < v.size())
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return {v.data(), remain_};
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return v;
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}
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pointer
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operator->() const = delete;
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const_iterator&
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operator++()
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{
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value_type const v = *it_++;
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remain_ -= v.size();
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return *this;
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}
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const_iterator
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operator++(int)
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{
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auto temp = *this;
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value_type const v = *it_++;
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remain_ -= v.size();
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return temp;
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}
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const_iterator&
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operator--()
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{
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value_type const v = *--it_;
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remain_ += v.size();
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return *this;
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}
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const_iterator
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operator--(int)
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{
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auto temp = *this;
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value_type const v = *--it_;
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remain_ += v.size();
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return temp;
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}
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private:
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const_iterator(
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buffers_prefix_view const& b,
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std::true_type)
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: b_(&b)
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, remain_(b.remain_)
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, it_(b_->end_)
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{
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}
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const_iterator(
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buffers_prefix_view const& b,
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std::false_type)
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: b_(&b)
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, remain_(b_->size_)
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, it_(net::buffer_sequence_begin(b_->bs_))
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{
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}
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};
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//------------------------------------------------------------------------------
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template<class Buffers>
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void
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buffers_prefix_view<Buffers>::
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setup(std::size_t size)
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{
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size_ = 0;
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remain_ = 0;
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end_ = net::buffer_sequence_begin(bs_);
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auto const last = bs_.end();
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while(end_ != last)
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{
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auto const len = buffer_bytes(*end_++);
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if(len >= size)
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{
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size_ += size;
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// by design, this subtraction can wrap
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BOOST_STATIC_ASSERT(std::is_unsigned<
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decltype(remain_)>::value);
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remain_ = size - len;
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break;
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}
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size -= len;
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size_ += len;
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}
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}
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template<class Buffers>
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buffers_prefix_view<Buffers>::
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buffers_prefix_view(
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buffers_prefix_view const& other,
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std::size_t dist)
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: bs_(other.bs_)
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, size_(other.size_)
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, remain_(other.remain_)
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, end_(std::next(bs_.begin(), dist))
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{
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}
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template<class Buffers>
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buffers_prefix_view<Buffers>::
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buffers_prefix_view(buffers_prefix_view const& other)
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: buffers_prefix_view(other,
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std::distance<iter_type>(
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net::buffer_sequence_begin(other.bs_),
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other.end_))
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{
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}
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template<class Buffers>
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auto
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buffers_prefix_view<Buffers>::
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operator=(buffers_prefix_view const& other) ->
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buffers_prefix_view&
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{
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auto const dist = std::distance<iter_type>(
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net::buffer_sequence_begin(other.bs_),
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other.end_);
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bs_ = other.bs_;
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size_ = other.size_;
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remain_ = other.remain_;
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end_ = std::next(
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net::buffer_sequence_begin(bs_),
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dist);
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return *this;
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}
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template<class Buffers>
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buffers_prefix_view<Buffers>::
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buffers_prefix_view(
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std::size_t size,
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Buffers const& bs)
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: bs_(bs)
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{
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setup(size);
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}
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template<class Buffers>
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template<class... Args>
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buffers_prefix_view<Buffers>::
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buffers_prefix_view(
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std::size_t size,
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boost::in_place_init_t,
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Args&&... args)
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: bs_(std::forward<Args>(args)...)
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{
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setup(size);
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}
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template<class Buffers>
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auto
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buffers_prefix_view<Buffers>::
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begin() const ->
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const_iterator
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{
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return const_iterator{
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*this, std::false_type{}};
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}
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template<class Buffers>
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auto
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buffers_prefix_view<Buffers>::
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end() const ->
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const_iterator
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{
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return const_iterator{
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*this, std::true_type{}};
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}
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//------------------------------------------------------------------------------
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template<>
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class buffers_prefix_view<net::const_buffer>
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: public net::const_buffer
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{
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public:
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using net::const_buffer::const_buffer;
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buffers_prefix_view(buffers_prefix_view const&) = default;
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buffers_prefix_view& operator=(buffers_prefix_view const&) = default;
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buffers_prefix_view(
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std::size_t size,
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net::const_buffer buffer)
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: net::const_buffer(
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buffer.data(),
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std::min<std::size_t>(size, buffer.size())
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#if defined(BOOST_ASIO_ENABLE_BUFFER_DEBUGGING)
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, buffer.get_debug_check()
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#endif
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)
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{
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}
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template<class... Args>
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buffers_prefix_view(
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std::size_t size,
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boost::in_place_init_t,
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Args&&... args)
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: buffers_prefix_view(size,
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net::const_buffer(
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std::forward<Args>(args)...))
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{
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}
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};
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//------------------------------------------------------------------------------
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template<>
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class buffers_prefix_view<net::mutable_buffer>
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: public net::mutable_buffer
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{
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public:
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using net::mutable_buffer::mutable_buffer;
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buffers_prefix_view(buffers_prefix_view const&) = default;
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buffers_prefix_view& operator=(buffers_prefix_view const&) = default;
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buffers_prefix_view(
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std::size_t size,
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net::mutable_buffer buffer)
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: net::mutable_buffer(
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buffer.data(),
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std::min<std::size_t>(size, buffer.size())
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#if defined(BOOST_ASIO_ENABLE_BUFFER_DEBUGGING)
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, buffer.get_debug_check()
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#endif
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)
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{
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}
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template<class... Args>
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buffers_prefix_view(
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std::size_t size,
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boost::in_place_init_t,
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Args&&... args)
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: buffers_prefix_view(size,
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net::mutable_buffer(
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std::forward<Args>(args)...))
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{
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}
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};
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} // beast
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} // boost
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#endif
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