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mirror of https://github.com/nlohmann/json synced 2024-11-23 12:30:06 +00:00

add detail/iterators/iteration_proxy.hpp

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Théo DELRIEU 2017-08-14 17:26:22 +02:00
parent bf06cf6c22
commit 5fc9ef2b90
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3 changed files with 102 additions and 87 deletions

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@ -15,7 +15,8 @@ SRCS = ${SRCDIR}/json.hpp \
${SRCDIR}/detail/parsing/parser.hpp \
${SRCDIR}/detail/iterators/primitive_iterator.hpp \
${SRCDIR}/detail/iterators/internal_iterator.hpp \
${SRCDIR}/detail/iterators/iter_impl.hpp
${SRCDIR}/detail/iterators/iter_impl.hpp \
${SRCDIR}/detail/iterators/iteration_proxy.hpp

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@ -0,0 +1,99 @@
#ifndef NLOHMANN_JSON_DETAIL_ITERATORS_ITERATION_PROXY_HPP
#define NLOHMANN_JSON_DETAIL_ITERATORS_ITERATION_PROXY_HPP
#include <cstddef>
#include <string>
namespace nlohmann
{
namespace detail
{
/// proxy class for the iterator_wrapper functions
template<typename IteratorType> class iteration_proxy
{
private:
/// helper class for iteration
class iteration_proxy_internal
{
private:
/// the iterator
IteratorType anchor;
/// an index for arrays (used to create key names)
std::size_t array_index = 0;
public:
explicit iteration_proxy_internal(IteratorType it) noexcept : anchor(it) {}
/// dereference operator (needed for range-based for)
iteration_proxy_internal& operator*()
{
return *this;
}
/// increment operator (needed for range-based for)
iteration_proxy_internal& operator++()
{
++anchor;
++array_index;
return *this;
}
/// inequality operator (needed for range-based for)
bool operator!=(const iteration_proxy_internal& o) const noexcept
{
return anchor != o.anchor;
}
/// return key of the iterator
std::string key() const
{
assert(anchor.m_object != nullptr);
switch (anchor.m_object->type())
{
// use integer array index as key
case value_t::array:
return std::to_string(array_index);
// use key from the object
case value_t::object:
return anchor.key();
// use an empty key for all primitive types
default:
return "";
}
}
/// return value of the iterator
typename IteratorType::reference value() const
{
return anchor.value();
}
};
/// the container to iterate
typename IteratorType::reference container;
public:
/// construct iteration proxy from a container
explicit iteration_proxy(typename IteratorType::reference cont)
: container(cont) {}
/// return iterator begin (needed for range-based for)
iteration_proxy_internal begin() noexcept
{
return iteration_proxy_internal(container.begin());
}
/// return iterator end (needed for range-based for)
iteration_proxy_internal end() noexcept
{
return iteration_proxy_internal(container.end());
}
};
}
}
#endif

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@ -63,6 +63,7 @@ SOFTWARE.
#include "detail/iterators/primitive_iterator.hpp"
#include "detail/iterators/internal_iterator.hpp"
#include "detail/iterators/iter_impl.hpp"
#include "detail/iterators/iteration_proxy.hpp"
/*!
@brief namespace for Niels Lohmann
@ -77,92 +78,6 @@ namespace detail
// iterators //
///////////////
/// proxy class for the iterator_wrapper functions
template<typename IteratorType> class iteration_proxy
{
private:
/// helper class for iteration
class iteration_proxy_internal
{
private:
/// the iterator
IteratorType anchor;
/// an index for arrays (used to create key names)
std::size_t array_index = 0;
public:
explicit iteration_proxy_internal(IteratorType it) noexcept : anchor(it) {}
/// dereference operator (needed for range-based for)
iteration_proxy_internal& operator*()
{
return *this;
}
/// increment operator (needed for range-based for)
iteration_proxy_internal& operator++()
{
++anchor;
++array_index;
return *this;
}
/// inequality operator (needed for range-based for)
bool operator!=(const iteration_proxy_internal& o) const noexcept
{
return anchor != o.anchor;
}
/// return key of the iterator
std::string key() const
{
assert(anchor.m_object != nullptr);
switch (anchor.m_object->type())
{
// use integer array index as key
case value_t::array:
return std::to_string(array_index);
// use key from the object
case value_t::object:
return anchor.key();
// use an empty key for all primitive types
default:
return "";
}
}
/// return value of the iterator
typename IteratorType::reference value() const
{
return anchor.value();
}
};
/// the container to iterate
typename IteratorType::reference container;
public:
/// construct iteration proxy from a container
explicit iteration_proxy(typename IteratorType::reference cont)
: container(cont) {}
/// return iterator begin (needed for range-based for)
iteration_proxy_internal begin() noexcept
{
return iteration_proxy_internal(container.begin());
}
/// return iterator end (needed for range-based for)
iteration_proxy_internal end() noexcept
{
return iteration_proxy_internal(container.end());
}
};
/*!
@brief a template for a reverse iterator class