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feat: segments_view iterator constructors
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‎include/boost/url/detail/segments_range.hpp‎

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//
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// Copyright (c) 2025 Alan de Freitas (alandefreitas@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_SEGMENTS_RANGE_HPP
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#define BOOST_URL_DETAIL_SEGMENTS_RANGE_HPP
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#include <boost/url/detail/config.hpp>
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#include <boost/url/detail/url_impl.hpp>
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#include <boost/url/segments_base.hpp>
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#include <boost/url/segments_encoded_base.hpp>
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#include <boost/core/detail/string_view.hpp>
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#include <boost/assert.hpp>
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namespace boost {
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namespace urls {
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namespace detail {
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struct segments_iter_access
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{
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static
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segments_iter_impl const&
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impl(segments_base::iterator const& it) noexcept
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{
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return it.it_;
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}
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static
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segments_iter_impl const&
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impl(segments_encoded_base::iterator const& it) noexcept
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{
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return it.it_;
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}
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};
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inline
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path_ref
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make_subref_from_impls(
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segments_iter_impl const& first,
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segments_iter_impl const& last) noexcept
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{
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BOOST_ASSERT(first.ref.alias_of(last.ref));
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path_ref const& ref = first.ref;
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std::size_t const i0 = first.index;
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std::size_t const i1 = last.index;
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BOOST_ASSERT(i0 <= i1);
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std::size_t const nseg = i1 - i0;
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bool const absolute = ref.buffer().starts_with('/');
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// Empty range
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if (nseg == 0)
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{
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std::size_t off0;
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if (i0 == 0)
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{
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// [begin, begin): don't include the leading '/'
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// for absolute, start right after the leading '/';
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if (absolute)
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{
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off0 = 1;
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}
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// for relative, start at the first segment character.
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else
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{
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off0 = first.pos;
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}
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}
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else
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{
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// [it, it) in the middle:
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// skip the separator before segment i0
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off0 = first.pos + 1;
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}
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core::string_view const sub(ref.data() + off0, 0);
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return {sub, 0, 0};
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}
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// General case: non-empty range
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// Start offset
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std::size_t off0;
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bool include_leading_slash = false;
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if (i0 == 0)
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{
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if (absolute)
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{
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// include leading '/'
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off0 = 0;
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include_leading_slash = true;
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}
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else
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{
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// relative: start at first segment
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off0 = first.pos;
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}
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}
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else
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{
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// skip slash before segment i0
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off0 = first.pos + 1;
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}
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// End offset
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std::size_t off1;
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if(i1 == ref.nseg())
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{
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off1 = ref.size();
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}
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else
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{
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// stop before the slash preceding i1
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off1 = last.pos;
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}
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BOOST_ASSERT(off1 >= off0);
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core::string_view const sub(ref.data() + off0, off1 - off0);
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// Decoded-length:
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// sum per-segment decoded lengths + internal '/' + the leading '/'.
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std::size_t dn_sum = 0;
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{
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// copy to iterate
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segments_iter_impl cur = first;
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for (std::size_t k = 0; k < nseg; ++k)
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{
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// per-segment decoded length
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dn_sum += cur.dn;
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cur.increment();
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}
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// internal '/'s
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dn_sum += (nseg - 1);
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// leading '/'
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if (include_leading_slash)
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{
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++dn_sum;
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}
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}
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return {sub, dn_sum, nseg};
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}
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template<class Iter>
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inline
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path_ref
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make_subref(Iter const& first, Iter const& last) noexcept
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{
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auto const& f = segments_iter_access::impl(first);
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auto const& l = segments_iter_access::impl(last);
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return make_subref_from_impls(f, l);
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}
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} // detail
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} // urls
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} // boost
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#endif

‎include/boost/url/impl/segments_base.hpp‎

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namespace boost {
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namespace urls {
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namespace detail {
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struct segments_iter_access;
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}
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class segments_base::iterator
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{
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detail::segments_iter_impl it_;
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friend class segments_base;
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friend class segments_ref;
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friend struct detail::segments_iter_access;
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iterator(detail::path_ref const&) noexcept;
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iterator(detail::path_ref const&, int) noexcept;

‎include/boost/url/impl/segments_encoded_base.hpp‎

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namespace boost {
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namespace urls {
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namespace detail {
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struct segments_iter_access;
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}
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class segments_encoded_base::iterator
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{
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friend class url_base;
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friend class segments_encoded_base;
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friend class segments_encoded_ref;
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friend struct detail::segments_iter_access;
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iterator(detail::path_ref const&) noexcept;
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iterator(detail::path_ref const&, int) noexcept;

‎include/boost/url/segments_encoded_view.hpp‎

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segments_encoded_view(
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core::string_view s);
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/** Constructor
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This function creates a new @ref segments_encoded_view
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from a pair of iterators referring to
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elements of another encoded segments
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view. The resulting view references
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the same underlying character buffer
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as the original.
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The caller is responsible for ensuring
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that the lifetime of the original buffer
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extends until the constructed view
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is no longer referenced.
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@par Example
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@code
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segments_encoded_view ps( "/path/to/file.txt" );
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segments_encoded_view sub(
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std::next(ps.begin()),
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ps.end());
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// sub represents "to/file.txt"
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@endcode
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@par Preconditions
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The iterators must be valid and belong to
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the same @ref segments_encoded_view.
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@par Postconditions
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`sub.buffer()` references characters in the
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original `ps.buffer()`.
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@par Complexity
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Linear in `sub.buffer()`
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@par Exception Safety
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Throws nothing.
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@param first The beginning iterator.
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@param last The ending iterator.
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*/
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BOOST_URL_DECL
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segments_encoded_view(
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iterator first,
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iterator last) noexcept;
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/** Assignment
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After assignment, both views

‎include/boost/url/segments_view.hpp‎

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segments_view(
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core::string_view s);
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/** Constructor
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This function creates a new @ref segments_view
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from a pair of iterators referring to
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elements of another segments view. The
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resulting view references the same
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underlying character buffer as the
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original.
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The caller is responsible for ensuring
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that the lifetime of the original buffer
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extends until the constructed view is no
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longer referenced.
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@par Example
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@code
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segments_view ps( "/path/to/file.txt" );
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segments_view sub(
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std::next(ps.begin()),
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ps.end());
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// sub represents "to/file.txt"
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@endcode
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@par Preconditions
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The iterators must be valid and belong to
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the same @ref segments_view.
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@par Postconditions
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`sub.buffer()` references characters in the
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original `ps.buffer()`.
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@par Complexity
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Linear in `sub.buffer()`
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@par Exception Safety
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Throws nothing.
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@param first The beginning iterator.
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@param last The ending iterator.
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*/
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BOOST_URL_DECL
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segments_view(
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iterator first,
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iterator last) noexcept;
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/** Assignment
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After assignment, both views

‎src/segments_encoded_view.cpp‎

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#include <boost/url/detail/config.hpp>
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#include <boost/url/detail/segments_range.hpp>
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#include <boost/url/segments_encoded_view.hpp>
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#include <boost/url/parse_path.hpp>
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{
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}
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segments_encoded_view::
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segments_encoded_view(iterator first, iterator last) noexcept
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: segments_encoded_base(detail::make_subref(first, last))
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{
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}
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segments_encoded_view::
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operator
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segments_view() const noexcept

‎src/segments_view.cpp‎

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#include <boost/url/detail/config.hpp>
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#include <boost/url/detail/segments_range.hpp>
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#include <boost/url/segments_view.hpp>
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#include <boost/url/parse_path.hpp>
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{
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}
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segments_view::
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segments_view(iterator first, iterator last) noexcept
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: segments_base(detail::make_subref(first, last))
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{
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}
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} // urls
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} // boost
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‎test/unit/segments_encoded_view.cpp‎

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BOOST_TEST_THROWS(segments_encoded_view("FA%"), system::system_error);
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}
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// segments_encoded_view(iterator, iterator)
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{
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segments_encoded_view ps = parse_path("/a/b/c").value();
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auto first = std::next(ps.begin());
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auto last = ps.end();
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segments_encoded_view sub(first, last);
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BOOST_TEST_EQ(sub.size(), 2u);
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BOOST_TEST(!sub.is_absolute());
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BOOST_TEST_EQ(sub.buffer(), "b/c");
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auto it = sub.begin();
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BOOST_TEST_EQ(*it++, "b");
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BOOST_TEST_EQ(*it++, "c");
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BOOST_TEST(it == sub.end());
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}
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// operator=(segments_encoded_view)
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{
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segments_encoded_view ps0("/path/to/file.txt");

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