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//
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//
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// Copyright (c) 2019 Vinnie Falco (vinnie.falco@gmail.com)
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// Copyright (c) 2019 Vinnie Falco (vinnie.falco@gmail.com)
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// Copyright (c) 2025 Mohammad Nejati
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// Copyright (c) 2025 Mohammad Nejati
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//
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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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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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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//
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// Official repository: https://github.com/cppalliance/http
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// Official repository: https://github.com/cppalliance/http
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//
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//
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#ifndef BOOST_HTTP_DETAIL_WORKSPACE_HPP
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#ifndef BOOST_HTTP_DETAIL_WORKSPACE_HPP
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#define BOOST_HTTP_DETAIL_WORKSPACE_HPP
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#define BOOST_HTTP_DETAIL_WORKSPACE_HPP
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#include <boost/http/detail/except.hpp>
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#include <boost/http/detail/except.hpp>
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#include <boost/assert.hpp>
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#include <boost/assert.hpp>
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#include <cstdlib>
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#include <cstdlib>
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#include <new>
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#include <new>
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#include <utility>
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#include <utility>
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#include <stddef.h> // ::max_align_t
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#include <stddef.h> // ::max_align_t
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namespace boost {
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namespace boost {
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namespace http {
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namespace http {
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namespace detail {
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namespace detail {
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/** A contiguous buffer of storage used by algorithms.
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/** A contiguous buffer of storage used by algorithms.
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    Objects of this type retain ownership of a
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    Objects of this type retain ownership of a
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    contiguous buffer of storage allocated upon
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    contiguous buffer of storage allocated upon
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    construction. This storage is divided into
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    construction. This storage is divided into
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    three regions:
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    three regions:
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    @code
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    @code
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    | front | free | acquired | back |
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    | front | free | acquired | back |
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    @endcode
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    @endcode
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    @li The reserved area, which starts at the
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    @li The reserved area, which starts at the
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        beginning of the buffer and can grow
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        beginning of the buffer and can grow
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        upwards towards the end of the buffer.
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        upwards towards the end of the buffer.
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    @li The acquired area, which starts at the
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    @li The acquired area, which starts at the
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        end of the buffer and can grow downwards
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        end of the buffer and can grow downwards
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        towards the beginning of the buffer.
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        towards the beginning of the buffer.
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    @li The unused area, which starts from the
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    @li The unused area, which starts from the
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        end of the reserved area and stretches
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        end of the reserved area and stretches
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        until the beginning of the acquired area.
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        until the beginning of the acquired area.
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*/
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*/
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class workspace
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class workspace
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{
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{
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    unsigned char* begin_ = nullptr;
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    unsigned char* begin_ = nullptr;
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    unsigned char* front_ = nullptr;
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    unsigned char* front_ = nullptr;
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    unsigned char* head_ = nullptr;
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    unsigned char* head_ = nullptr;
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    unsigned char* back_ = nullptr;
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    unsigned char* back_ = nullptr;
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    unsigned char* end_ = nullptr;
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    unsigned char* end_ = nullptr;
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    template<class>
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    template<class>
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    struct any_impl;
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    struct any_impl;
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    struct any;
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    struct any;
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    struct undo;
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    struct undo;
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public:
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public:
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    /** Return the number of aligned bytes required for T
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    /** Return the number of aligned bytes required for T
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    */
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    */
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    template<class T>
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    template<class T>
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    static
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    static
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    constexpr
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    constexpr
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    std::size_t
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    std::size_t
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    space_needed();
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    space_needed();
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    /** Destructor.
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    /** Destructor.
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    */
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    */
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    ~workspace();
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    ~workspace();
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    /** Constructor.
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    /** Constructor.
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        @param n The number of bytes of storage
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        @param n The number of bytes of storage
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            to allocate for the internal buffer.
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            to allocate for the internal buffer.
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    */
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    */
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    explicit
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    explicit
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    workspace(
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    workspace(
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        std::size_t n);
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        std::size_t n);
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    /** Constructor.
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    /** Constructor.
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    */
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    */
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    workspace() = default;
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    workspace() = default;
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    /** Constructor.
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    /** Constructor.
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    */
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    */
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    workspace(workspace&&) noexcept;
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    workspace(workspace&&) noexcept;
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    /** Assignment.
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    /** Assignment.
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    */
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    */
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    workspace&
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    workspace&
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    operator=(workspace&&) noexcept;
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    operator=(workspace&&) noexcept;
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    /** Allocate internal storage.
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    /** Allocate internal storage.
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        @throw std::logic_error this->size() > 0
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        @throw std::logic_error this->size() > 0
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        @throw std::invalid_argument n == 0
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        @throw std::invalid_argument n == 0
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    */
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    */
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    void
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    void
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    allocate(
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    allocate(
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        std::size_t n);
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        std::size_t n);
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    /** Return a pointer to the unused area.
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    /** Return a pointer to the unused area.
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    */
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    */
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    unsigned char*
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    unsigned char*
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    data() noexcept
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    data() noexcept
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    {
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    {
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        return front_;
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        return front_;
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    }
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    }
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    /** Return the size of the unused area.
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    /** Return the size of the unused area.
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    */
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    */
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    std::size_t
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    std::size_t
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    size() const noexcept
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    size() const noexcept
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    {
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    {
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        return head_ - front_;
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        return head_ - front_;
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    }
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    }
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    /** Clear the contents while preserving capacity.
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    /** Clear the contents while preserving capacity.
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    */
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    */
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    BOOST_HTTP_DECL
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    BOOST_HTTP_DECL
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    void
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    void
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    clear() noexcept;
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    clear() noexcept;
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    /** Convert unused storage to reserved storage.
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    /** Convert unused storage to reserved storage.
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        @throw std::invalid_argument n >= this->size()
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        @throw std::invalid_argument n >= this->size()
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    */
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    */
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    BOOST_HTTP_DECL
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    BOOST_HTTP_DECL
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    unsigned char*
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    unsigned char*
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    reserve_front(
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    reserve_front(
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        std::size_t n);
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        std::size_t n);
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    /** Convert unused storage to reserved storage.
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    /** Convert unused storage to reserved storage.
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        @return nullptr if n >= this->size()
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        @return nullptr if n >= this->size()
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    */
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    */
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    BOOST_HTTP_DECL
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    BOOST_HTTP_DECL
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    unsigned char*
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    unsigned char*
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    try_reserve_front(
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    try_reserve_front(
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        std::size_t n) noexcept;
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        std::size_t n) noexcept;
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    template<class T, class... Args>
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    template<class T, class... Args>
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    typename std::decay<T>::type&
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    typename std::decay<T>::type&
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    emplace(Args&&... args);
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    emplace(Args&&... args);
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    template<class T>
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    template<class T>
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    T*
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    T*
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    push_array(
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    push_array(
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        std::size_t n,
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        std::size_t n,
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        T const& t);
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        T const& t);
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    BOOST_HTTP_DECL
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    BOOST_HTTP_DECL
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    unsigned char*
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    unsigned char*
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    reserve_back(
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    reserve_back(
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        std::size_t n);
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        std::size_t n);
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private:
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private:
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    BOOST_HTTP_DECL
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    BOOST_HTTP_DECL
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    unsigned char*
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    unsigned char*
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    bump_down(
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    bump_down(
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        std::size_t size,
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        std::size_t size,
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        std::size_t align);
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        std::size_t align);
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};
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};
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} // detail
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} // detail
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} // http
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} // http
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} // boost
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} // boost
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#include <boost/http/detail/impl/workspace.hpp>
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#include <boost/http/detail/impl/workspace.hpp>
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#endif
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#endif