* Move instead of deep-copy ordered_json values when an object grows
ordered_map keeps its elements in a std::vector<std::pair<const Key, T>>.
With a std::string key, that pair is not nothrow move constructible (the
const key has to be copied), so std::vector copies every element when it
reallocates. For ordered_json, this deep-copies every member value an
object already holds, including whole nested subtrees, on each growth
step.
Grow the storage in ordered_map instead, copying the keys and moving the
values. This happens in two phases, so the strong exception guarantee is
kept without try/catch. The first phase may throw, but only touches a
temporary buffer: it copies the keys, value-initializes the values, and
constructs the new element. The second phase moves the values (noexcept)
and swaps the buffers. Because the new element is constructed before any
value is moved, arguments that refer to elements of the container stay
valid, as with std::vector. Types that cannot take this path keep the
std::vector behavior.
Parsing into ordered_json (ParseStringOrdered, Apple M1 Max, clang -O3):
twitter 3.20 -> 1.70 ms, citm_catalog 7.73 -> 3.67 ms, jeopardy 219 ->
177 ms, canada unchanged. The number of allocations for twitter and
citm_catalog drops by two thirds.
Also add ParseStringOrdered rows to the benchmarks, and document the
growth behavior and the exception safety of ordered_map.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Fix CI: skip std::pair noexcept assumptions on EDG-based compilers
ci_icpc and ci_nvhpc failed to compile unit-ordered_map.cpp: the static
assertion that std::pair<const std::string, ordered_json> is not nothrow
move-constructible fails there. The EDG front end (Intel icpc 2021.10,
NVIDIA nvc++ 25.5) considers the defaulted move constructor of
std::pair<const Key, T> noexcept even if copying Key can throw. With these
compilers, std::vector already moves such elements itself when it grows,
and ordered_map correctly leaves growing to it.
The same misjudgement makes std::vector call std::terminate when a key copy
throws during growth, so the exception-safety test with throwing_key would
abort on these compilers as well.
Skip the static assertion and the exception-safety section when __EDG__ is
defined. Verified with icpc 2021.10 (-std=gnu++11) and nvc++ 25.5 (C++11 and
C++17) on Compiler Explorer: unit-ordered_map and unit-disabled_exceptions
build and pass.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
---------
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Fix compile error when using nlohmann ordered_map with WITH_DEFAULT macros
ordered_map inherits its copy and move assignment from the underlying std vector, which requires value_type to be CopyAssignable. value_type is pair<const Key, T> whose assignment is deleted because of the const Key, so any code that assigns ordered_map (for example the ternary in NLOHMANN_JSON_FROM_WITH_DEFAULT) fails to compile (issue #5122). Provide assignment operators on ordered_map that rebuild via clear plus push_back for copy and transfer the underlying buffer for move, neither of which needs pair assignment. Also switch the map-shaped from_json overload from a transform plus inserter idiom to a range-for plus emplace, which avoids the same hazard.
Signed-off-by: Samaresh Kumar Singh <ssam3003@gmail.com>
* Update ordered_map.hpp
removed unwanted comments
Signed-off-by: SamareshSingh <97642706+ssam18@users.noreply.github.com>
Signed-off-by: Samaresh Kumar Singh <ssam3003@gmail.com>
* Update json.hpp
Signed-off-by: SamareshSingh <97642706+ssam18@users.noreply.github.com>
Signed-off-by: Samaresh Kumar Singh <ssam3003@gmail.com>
* Address CI issues for ordered_map fix
Declare an explicit defaulted destructor on ordered_map so the rule of five is complete (clang-tidy cppcoreguidelines-special-member-functions and hicpp-special-member-functions). Initialize the ordered_map field in the regression test struct so GCC effective-C++ stops flagging Example_5122 with a missing member initializer.
Signed-off-by: Samaresh Kumar Singh <ssam3003@gmail.com>
* Suppress redundant-member-init lint on Example_5122::c
The empty brace-init on c{} is required by GCC -Weffc++ to mark the member as initialized in the synthesized default constructor, but clang-tidy readability-redundant-member-init flags the same line because ordered_map already has a default constructor. The two checks pull in opposite directions, so add a targeted NOLINT to keep both happy.
Signed-off-by: Samaresh Kumar Singh <ssam3003@gmail.com>
* Address review: strong exception safety in copy-assign, simplify move-assign noexcept
Copy assignment now constructs a temporary copy before move-assigning the
Container subobject, preserving *this if the copy throws. Move assignment
uses std::is_nothrow_move_assignable<Container> for a cleaner noexcept
specifier, matching the style of the move constructor.
Signed-off-by: Samaresh Kumar Singh <ssam3003@gmail.com>
* Restore self-assignment check in copy-assign to satisfy cert-oop54-cpp
clang-tidy's cert-oop54-cpp flagged the previous revision because it could
not recognize the implicit self-safety of the copy-then-move pattern.
Restore the explicit `if (this != &other)` guard — strong exception safety
is preserved since the temporary copy is still constructed before the
move-assign of the Container subobject.
Signed-off-by: Samaresh Kumar Singh <ssam3003@gmail.com>
* Address review: add explicit self-assignment and move-assignment tests for ordered_map
Signed-off-by: Samaresh Kumar Singh <ssam3003@gmail.com>
* Address review: gate -Wself-assign-overloaded suppression on Clang version
-Wself-assign-overloaded was introduced in Clang 7. Older Clang versions fail the build with "unknown warning group" when the suppression pragma references it unconditionally. Use __has_warning inside an __clang__ branch so the suppression is only emitted on Clang versions that recognize the warning. The inner check stays inside the __clang__ guard because GCC does not provide __has_warning and would tokenize-error on the argument list.
Signed-off-by: Samaresh Kumar Singh <ssam3003@gmail.com>
* Address CI: drop unused gating macro to silence -Wunused-macros
The previous attempt defined JSON_TEST_5122_SUPPRESS_SELF_ASSIGN_OVERLOADED
as 0 unconditionally and then overrode it to 1 on Clang versions that recognize the warning. On those Clangs the initial define is immediately
undef'd without being read, which trips Clang's -Wunused-macros under -Weverything in the ci_test_clang job. Drop the macro and gate the
DOCTEST_CLANG_SUPPRESS_WARNING_PUSH/POP pragmas directly with __has_warning inside the existing __clang__ branch.
Signed-off-by: Samaresh Kumar Singh <ssam3003@gmail.com>
---------
Signed-off-by: Samaresh Kumar Singh <ssam3003@gmail.com>
Signed-off-by: SamareshSingh <97642706+ssam18@users.noreply.github.com>
* Add versioned inline namespace
Add a versioned inline namespace to prevent ABI issues when linking code
using multiple library versions.
* Add namespace macros
* Encode ABI information in inline namespace
Add _diag suffix to inline namespace if JSON_DIAGNOSTICS is enabled, and
_ldvcmp suffix if JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON is enabled.
* Move ABI-affecting macros into abi_macros.hpp
* Move std_fs namespace definition into std_fs.hpp
* Remove std_fs namespace from unit test
* Format more files in tests directory
* Add unit tests
* Update documentation
* Fix GDB pretty printer
* fixup! Add namespace macros
* Derive ABI prefix from NLOHMANN_JSON_VERSION_*
* Add overloads for more key types to ordered_map
Add overloads to accept additional key types defined by type trait
detail::is_usable_as_key_type to ordered_map.
The same key types that can be used with json can now also be used with
ordered_json.
* Fix ordered_map::erase(first, last) with first == last
* Modify element access unit test to also test ordered_json
* Add key_compare member to ordered_map
* Replace == with key_compare in ordered_map
* Expose the actual comparison function used by object_t
nlohmann::ordered_map uses a different comparison function than the one
provided via template parameter.
* Introduce a type trait to detect if object_t has a key_compare member.
* Rename object_comparator_t to default_object_comparator_t.
* Add object_comparator_t to be conditionally defined as
object_t::key_compare, if available, or default_object_comparator_t
otherwise.
* Update the documentation accordingly.
Co-authored-by: Niels Lohmann <niels.lohmann@gmail.com>
* Add type traits to check if a type is usable as object key
Add type trait to check:
* if a type is a specialization of a template.
* if a type is a json_pointer.
* if a type is a basic_json::{const_,}iterator.
* if two types are comparable using a given comparison functor.
* if a type is comparable to basic_json::object_t::key_type.
* if a type has a member type is_transparent.
* if a type is usable as object key.
* if a type has an erase() function accepting a given KeyType.
Co-authored-by: Niels Lohmann <niels.lohmann@gmail.com>
* Rework basic_json element access to accept more key types
Rework basic_json element access member functions and operators to
accept any type that meets the requirements defined by type trait
detail::is_usable_as_key_type.
Member functions and operators:
* at()
* operator[]
* value()
* erase()
* find()
* count()
* contains()
Update documentation to reflect these changes.
Add unit tests to excercise the new functions using std::string_view.
Co-authored-by: Niels Lohmann <niels.lohmann@gmail.com>
Co-authored-by: Niels Lohmann <niels.lohmann@gmail.com>
* 🔧 use proper GCC binary
* 🔧 add more GCC warning flags
* ⚗️ try fix from https://github.com/nlohmann/json/issues/3138#issuecomment-1015562666
* Fix custom allocator test build failures (C++20)
Allocator tests fail to compile in C++20 mode with clang+MS STL due
to missing copy constructors.
* Fix test build failures due to missing noexcept (gcc-12)
* alt_string has multiple member functions that should be marked noexcept.
* nlohmann::ordered_map constructors can be noexcept.
Compilation failures result from the warning flag -Werror=noexcept and
gcc-12.
* Disable broken comparison tests in C++20 mode
Co-authored-by: Niels Lohmann <mail@nlohmann.me>
One of the ordered_map constructors was incorrectly accepting a
std::initializer_list<T> instead of std::initializer_list<value_type>.
Add regression test.
Fixes#3343.
