Merge pull request #1134 from Daniel599/feature/items_iterator

fixed compile error for #1045

include/nlohmann/detail/conversions/to_json.hpp

@@ -294,6 +294,16 @@ void to_json(BasicJsonType& j, const std::pair<Args...>& p)
  j = {p.first, p.second};
 }
 
+template<typename IteratorType> class iteration_proxy; // TODO: Forward decl needed, maybe move somewhere else
+template<typename BasicJsonType, typename T,
+ enable_if_t<std::is_same<T, typename iteration_proxy<typename BasicJsonType::iterator>::iteration_proxy_internal>::value, int> = 0>
+void to_json(BasicJsonType& j, T b) noexcept
+{
+ typename BasicJsonType::object_t tmp_obj;
+ tmp_obj[b.key()] = b.value(); // TODO: maybe there is a better way?
+ external_constructor<value_t::object>::construct(j, std::move(tmp_obj));
+}
+
 template<typename BasicJsonType, typename Tuple, std::size_t... Idx>
 void to_json_tuple_impl(BasicJsonType& j, const Tuple& t, index_sequence<Idx...>)
 {

include/nlohmann/detail/iterators/iteration_proxy.hpp

@@ -2,6 +2,7 @@
 
 #include <cstddef> // size_t
 #include <string> // string, to_string
+#include <iterator> // input_iterator_tag
 
 #include <nlohmann/detail/value_t.hpp>
 
@@ -16,6 +17,13 @@ template<typename IteratorType> class iteration_proxy
  /// helper class for iteration
  class iteration_proxy_internal
  {
+ public:
+ using difference_type = std::ptrdiff_t;
+ using value_type = iteration_proxy_internal;
+ using pointer = iteration_proxy_internal*;
+ using reference = iteration_proxy_internal&;
+ using iterator_category = std::input_iterator_tag;
+
  private:
  /// the iterator
  IteratorType anchor;
@@ -31,6 +39,9 @@ template<typename IteratorType> class iteration_proxy
  public:
  explicit iteration_proxy_internal(IteratorType it) noexcept : anchor(it) {}
 
+ iteration_proxy_internal(const iteration_proxy_internal&) = default;
+ iteration_proxy_internal& operator=(const iteration_proxy_internal&) = default;
+
  /// dereference operator (needed for range-based for)
  iteration_proxy_internal& operator*()
  {
@@ -46,6 +57,12 @@ template<typename IteratorType> class iteration_proxy
  return *this;
  }
 
+ /// equality operator (needed for InputIterator)
+ bool operator==(const iteration_proxy_internal& o) const noexcept
+ {
+ return anchor == o.anchor;
+ }
+
  /// inequality operator (needed for range-based for)
  bool operator!=(const iteration_proxy_internal& o) const noexcept
  {

single_include/nlohmann/json.hpp

@@ -1606,6 +1606,16 @@ void to_json(BasicJsonType& j, const std::pair<Args...>& p)
  j = {p.first, p.second};
 }
 
+template<typename IteratorType> class iteration_proxy; // TODO: Forward decl needed, maybe move somewhere else
+template<typename BasicJsonType, typename T,
+ enable_if_t<std::is_same<T, typename iteration_proxy<typename BasicJsonType::iterator>::iteration_proxy_internal>::value, int> = 0>
+void to_json(BasicJsonType& j, T b) noexcept
+{
+ typename BasicJsonType::object_t tmp_obj;
+ tmp_obj[b.key()] = b.value(); // TODO: maybe there is a better way?
+ external_constructor<value_t::object>::construct(j, std::move(tmp_obj));
+}
+
 template<typename BasicJsonType, typename Tuple, std::size_t... Idx>
 void to_json_tuple_impl(BasicJsonType& j, const Tuple& t, index_sequence<Idx...>)
 {
@@ -5329,6 +5339,7 @@ class iter_impl
 
 #include <cstddef> // size_t
 #include <string> // string, to_string
+#include <iterator> // input_iterator_tag
 
 // #include <nlohmann/detail/value_t.hpp>
 
@@ -5344,6 +5355,13 @@ template<typename IteratorType> class iteration_proxy
  /// helper class for iteration
  class iteration_proxy_internal
  {
+ public:
+ using difference_type = std::ptrdiff_t;
+ using value_type = iteration_proxy_internal;
+ using pointer = iteration_proxy_internal*;
+ using reference = iteration_proxy_internal&;
+ using iterator_category = std::input_iterator_tag;
+
  private:
  /// the iterator
  IteratorType anchor;
@@ -5359,6 +5377,9 @@ template<typename IteratorType> class iteration_proxy
  public:
  explicit iteration_proxy_internal(IteratorType it) noexcept : anchor(it) {}
 
+ iteration_proxy_internal(const iteration_proxy_internal&) = default;
+ iteration_proxy_internal& operator=(const iteration_proxy_internal&) = default;
+
  /// dereference operator (needed for range-based for)
  iteration_proxy_internal& operator*()
  {
@@ -5374,6 +5395,12 @@ template<typename IteratorType> class iteration_proxy
  return *this;
  }
 
+ /// equality operator (needed for InputIterator)
+ bool operator==(const iteration_proxy_internal& o) const noexcept
+ {
+ return anchor == o.anchor;
+ }
+
  /// inequality operator (needed for range-based for)
  bool operator!=(const iteration_proxy_internal& o) const noexcept
  {
@@ -8544,7 +8571,7 @@ boundaries compute_boundaries(FloatType value)
  constexpr int kMinExp = 1 - kBias;
  constexpr uint64_t kHiddenBit = uint64_t{1} << (kPrecision - 1); // = 2^(p-1)
 
- using bits_type = typename std::conditional< kPrecision == 24, uint32_t, uint64_t >::type;
+ using bits_type = typename std::conditional<kPrecision == 24, uint32_t, uint64_t>::type;
 
  const uint64_t bits = reinterpret_bits<bits_type>(value);
  const uint64_t E = bits >> (kPrecision - 1);
@@ -8955,7 +8982,10 @@ inline void grisu2_digit_gen(char* buffer, int& length, int& decimal_exponent,
  // = ((p1 ) * 2^-e + (p2 )) * 2^e
  // = p1 + p2 * 2^e
 
- const diyfp one(uint64_t{1} << -M_plus.e, M_plus.e);
+ const diyfp one(uint64_t
+ {
+ 1
+ } << -M_plus.e, M_plus.e);
 
  uint32_t p1 = static_cast<uint32_t>(M_plus.f >> -one.e); // p1 = f div 2^-e (Since -e >= 32, p1 fits into a 32-bit int.)
  uint64_t p2 = M_plus.f & (one.f - 1); // p2 = f mod 2^-e
@@ -18475,7 +18505,7 @@ struct hash<nlohmann::json>
 /// @note: do not remove the space after '<',
 /// see https://github.com/nlohmann/json/pull/679
 template<>
-struct less< ::nlohmann::detail::value_t>
+struct less<::nlohmann::detail::value_t>
 {
  /*!
  @brief compare two value_t enum values

test/src/unit-regression.cpp

@@ -1581,4 +1581,26 @@ TEST_CASE("regression tests")
  float_json j2 = {1000.0, 2000.0, 3000.0};
  CHECK(float_json::from_ubjson(float_json::to_ubjson(j2, true, true)) == j2);
  }
+
+ SECTION("issue #1045 - Using STL algorithms with JSON containers with expected results?")
+ {
+ json diffs = nlohmann::json::array();
+ json m1{{"key1", 42}};
+ json m2{{"key2", 42}};
+ auto p1 = m1.items();
+ auto p2 = m2.items();
+
+ using it_type = decltype(p1.begin());
+
+ std::set_difference(
+ p1.begin(), p1.end(),
+ p2.begin(), p2.end(),
+ std::inserter(diffs, diffs.end()), [&](const it_type & e1, const it_type & e2) -> bool
+ {
+ using comper_pair = std::pair<std::string, decltype(e1.value())>; // Trying to avoid unneeded copy
+ return comper_pair(e1.key(), e1.value()) < comper_pair(e2.key(), e2.value()); // Using pair comper
+ });
+
+ CHECK(diffs.size() == 1); // Note the change here, was 2
+ }
 }