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//
 
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// Copyright (c) 2019 Vinnie Falco (vinnie.falco@gmail.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/url
 
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//
 
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#ifndef BOOST_URL_DETAIL_MOVE_CHARS_HPP
 
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#define BOOST_URL_DETAIL_MOVE_CHARS_HPP
 
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#include <boost/core/detail/string_view.hpp>
 
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#include <boost/assert.hpp>
 
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#include <cstring>
 
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#include <functional>
 
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namespace boost {
 
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namespace urls {
 
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namespace detail {
 
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// Moves characters, and adjusts any passed
 
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// views if they point to any moved characters.
 
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// true if s completely overlapped by buf
 
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inline
 
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bool
 
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is_overlapping(
 
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    core::string_view buf,
 
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    core::string_view s) noexcept
 
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{
 
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    auto const b0 = buf.data();
 
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    auto const e0 = b0 + buf.size();
 
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    auto const b1 = s.data();
 
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    auto const e1 = b1 + s.size();
 
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    auto const less_equal =
 
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        std::less_equal<char const*>();
 
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    if(less_equal(e0, b1))
 
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        return false;
 
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    if(less_equal(e1, b0))
 
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        return false;
 
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    // partial overlap is undefined
 
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    BOOST_ASSERT(less_equal(e1, e0));
 
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    BOOST_ASSERT(less_equal(b0, b1));
 
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    return true;
 
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}
 
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inline
 
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void
 
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move_chars_impl(
 
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    std::ptrdiff_t,
 
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    core::string_view const&) noexcept
 
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{
 
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}
 
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template<class... Sn>
 
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void
 
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move_chars_impl(
 
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    std::ptrdiff_t d,
 
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    core::string_view const& buf,
 
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    core::string_view& s,
 
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    Sn&... sn) noexcept
 
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{
 
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    if(is_overlapping(buf, s))
 
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        s = {s.data() + d, s.size()};
 
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    move_chars_impl(d, buf, sn...);
 
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}
 
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template<class... Args>
 
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void
 
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move_chars(
 
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    char* dest,
 
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    char const* src,
 
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    std::size_t n,
 
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    Args&... args) noexcept
 
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{
 
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    move_chars_impl(
 
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        dest - src,
 
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        core::string_view(src, n),
 
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        args...);
 
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    std::memmove(
 
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        dest, src, n);
 
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}
 
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} // detail
 
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} // urls
 
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} // boost
 
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#endif