- Implemented "copy" in terms of "add".
- Added check for JSON Pointer array indices to make sure the complete reference token was processed.
- Added test suite from https://github.com/json-patch/json-patch-tests
The at function throws json::out_of_range.403 when a nonexistent object key is provided (just like the usual at function). This was not documented and users could assume json::out_of_range.404 would be thrown instead.
- Updated documentation.
- Added example code.
We had a lot of issues with failing roundtrips (i.e., parse errors from serializations) in case string were stored in the library that were not UTF-8 encoded. This PR adds an exception in this case.
The example in the documentation on how to "force" an array of arrays was wrong since the first release. Fixed the documentation and added checks for the README unit tests.
Hey, thanks for this great library which I've used in many occasions now. I know it's not much, but I wanted to contribute at least a tiny bit back to you by this PR :-) Keep up the good work!
o For some unknown reason, the complexity of the benchmark platform
prevented some C++ compilers from generating optimal code, properly
reflective of the real performance in actual deployment.
o Added the json_benchmarks_simple target, which performs the same
suite of tests as json_benchmarks.
o Simplified the benchmark platform, and emit an "Average" TPS
(Transactions Per Second) value reflective of aggregate parse/output
performance.
o We assume the same character int_type as the unerlying std::istream
o There are no assumptions on the value of eof(), other than that it
will not be a valid unsigned char value.
o To retain performance, we do not allow swapping out the underlying
std::streambuf during our use of the std::istream for parsing.
o We can retain -Weffc++ and specify default initializers by using
initializer lists. The risks are low (of additional non-conformat
compilers), because there is already one other such initialization
used in the code-base.
o An (-'ve valued, typically -1) EOF must never be allowed in
token_string, as it be converted to 255 -- a legitimate value.
o Comparing against a specific eof() (-1, typically) is more costly than
detecting +'ve/-'ve. Since EOF is the only non-positive value allowed
we can use the simpler test.
o Removed unnecessary test for token_string size, as it is already
tested in the method, and must never occur in correct code; used an
assert instead.
o Return its contents when necessary. In many cases, this avoids
construction of multiple copies of the yytext token. Exceeds
performance of current develop branch.
o Use std::streambuf I/O instead of std::istream; does not maintain
(unused) istream flags.
o Further simplify get/unget handling.
o Restore original handling of NUL in input stream; ignored during
token_string escaping.
The CBOR and MessagePack parsers now expect the input to be read until the end. Unless the new parameter "strict" is set to false (it is true by default), an exception is raised if the parser ends prematurely. This is a breaking change as the parsers ignored unread input so far.
Furthermore, the offset/startIndex paramter introduced in #462 was removed as this behavior can be mimicked with an iterator range. For instance, instead of calling "from_cbor(vec, 5);", you can write "from_cbor({vec.begin()+5, vec.end()});".
o To prevent the compilation issue on OSX with the intel compiler suite. The
error was found with icpc version 15.0.3.187 where the "__clang_version__" was
not defined correctly, while "__clang__" was.
- replaced list of pairs by flat list in next_byte_in_range
- implemented early exit in case of parse errors
- reused memory for object keys
- direct calls to embedded objects/arrays for insertions
The rewrite uses more cmake build-in automatisms and build-in generates
variables to allow better generic reuse.
* cmake files are installed to
``` <install_prefix>/lib/cmake/nlohmann_json/ ``` for best support on
most systems
* include path is set to ``` include ``` for usage as ``` #include
<nlohmann/json.hpp> ```
You can now pass a boolean "allow_exceptions" to the parse functions. If it is false, no exceptions are thrown in case of a parse error. Instead, parsing is stopped at the first error and a JSON value of type "discarded" (check with is_discarded()) is returned.
On MSVC compiler, temporaries that are constructed during a
list initialization, are sometimes destroyed even before calling
the initializing constructor, instead of at the end of the
containing full-expression. This is clearly non-conforming to
[class.temporary].
As the impact of this bug is silently producing incorrect
JSON values, move eagerly from rvalues to be safe.
See https://stackoverflow.com/questions/24586411
- You can now pass a reference to a vector to the to_cbor and to_msgpack functions. The output will be written (appended) to the vector. #476
- You can now pass an output stream with uint8_t character type to the to_cbor and to_msgpack functions. #477
- You can now read from uint8_t */size in the to_cbor and to_msgpack functions. An input adapter will be created from this pair, so you need to use braces. #478
This commit works around an issue in std::initializer_list design.
By using a detail::json_ref proxy with a mutable value inside,
rvalue-ness of an input to list initializer is remembered and
used later to move from the proxy instead of copying.
Travis found an error with Clang 3.8's sanitizers, see https://travis-ci.org/nlohmann/json/jobs/256366699. Unfortunately, I cannot reproduce this error with clang version 6.0.0 (trunk 308825) locally. However, this seems to be an issue, because so far, we did not reset a value after moving from it.
A complete rewrite of the string escape function. It now provides codepoint-to-\uxxxx escaping. Invalid UTF-8 byte sequences are not escaped, but copied as-is. I haven’t spent much time optimizing the code - but the library now agrees with Python on every single Unicode character’s escaping (see file test/data/json_nlohmann_tests/all_unicode_ascii.json).
Other minor changes: replaced "size_t" by "std::size_t"
It makes no sense to have this special exception. Instead of throwing when an input adapter is created, it is better to detect a parse error in later usage when an EOF is "read" unexpectedly.
These breaks were just added to silence a GCC warning - the GCC is right about warning as it cannot know that the expect function will not return in these two scenarios.
It seems these functions are not required any more. The code was added in commit 7e32457 to fix issue #171. There are still regression tests for #171, so when this commit passes the CI, the functions may be removed for good.
When an empty vector was passed to the parse function, an empty iterator range was used to construct an input iterator. Unfortunately, we then cannot use the start iterator to derive a pointer from.
Found with Xcode's undefined behavior sanitizer.
An optional parameter for dump() allows to set the character to use for
indentation (default: space). In case a JSON value is serialized to an
output stream, its fill character is used (and can be set with
std::setfill).
Creates all well-formed sequences of bytes up to length 4. Furthermore,
creates ill-formed sequences by removing required trailing bytes or
changing bytes. As the tests can take a lot of time, preprocessor
symbols are introduced.
As I learned in https://github.com/melpon/wandbox/issues/209, this
library is already installed at Wandbox, so we need to adjust the
examples to use `#include "json.hpp"` insteas of `#include <json.hpp>`.
These classes are now constructed with an interface adapter. This moves
complexity from various places into the interface adapter class, or to
some factories which now implement the different flavors of input.
Furthermore, input adapters are kept in std::shared_ptr to avoid the
need of manual deletion.
We totally forgot to implement the comparison operators other than ==
and != for scalar types. Consequently, comparing a JSON value with a
scalar type led to compile errors.
- removed uncached input stream adapter; it was too slow anyway
- implemented a class binary_read which parses CBOR based on input
adapters
- in the CBOR parser, numbers are created via memcpy to avoid undefined
behavior
The solution with a std::runtime_error member is more elegant. It
allows to have std::exception as base class again. However, I still
have no idea why GCC thinks the copy constructor may throw...
To have nothrow-copy-constructible exceptions, we inherit from
std::runtime_error which can cope with arbitrary-length error messages.
Intermediate strings are built with static functions and then passed to
the actual constructor.
This commit removed the re2c lexer and replaced it by a manual version.
Its integration is not yet complete: number parsing does not respect
locales or overflows. Furthermore, parsing does not need to end with
EOF. Therefore, a lot of test cases fail. The idea is to push this
branch forward so we can conduct performance comparisons. So far, a
nice side effect are better diagnosis messages in case of parse errors.
We should compare the binary serializations rather than the JSON values
themselves. This fix was already done for CBOR and apparently forgotten
for MessagePack.
- Removed unused headers.
- Added override where needed.
- Added description for parse_error.113 exception.
- Fixed some conversion warnings.
- Integrated cbor_expect_string function for CBOR maps.
- Added documentation on the supported CBOR/MessagePack features.
- Added test to check all initial bytes for CBOR input.
When <Windows.h> is included with MSVC, a macro NOMINMAX is defined
that yields compilation errors when max/min calls are encountered. This
can be fixed by un-defining NOMINMAX, or by placing parentheses around
all min/max calls. We chose the latter.
Since #329, NaN and inf numbers do not yield an exception, but are
stored internally and are dumped as “null”. This commit adjusts the
fuzz testers to deal with this special case.
- If an overflow occurs during parsing a number from a JSON text, an
exception (std::out_of_range for the moment, to be replaced by a
user-defined exception #244) is thrown so that the overflow is detected
early and roundtripping is guaranteed.
- NaN and INF floating-point values can be stored in a JSON value and
are not replaced by null. That is, the basic_json class behaves like
double in this regard (no exception occurs). However, NaN and INF are
serialized to “null”.
- Adjusted test cases appropriately.
To avoid the error described in #497, I added a function
msgpack_expect_string that is executed every time a string is expected
during the parsing of a map. In case the current byte does not belong
to a MsgPack string, an exception is thrown.
This test case relied on logics that have been replaced by CMake with
#461. This change enables compilation and execution of the test suite
without exceptions by adding an after_success task.
Added a test to check if the input stream is good() before executing
getline on it. Also added two test cases that set the failbit and
badbit before calling file_line_buffer.
I used __EXCEPTIONS to detect whether exceptions are supported.
Apparently, this is a macro that is only used by libstdc++
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64276). It’s much cleaner
to use __cpp_exceptions as it is in the standard since C++98.
Note that compiling the unit-tests with “-fno-exceptions” still does
not work, because Catch uses throw internally. However, the library’s
exceptions can be switched off by defining JSON_NOEXCEPTION.
The original test case relied on an invalidated iterator. This error
did not occur before, but only with GCC with -D_GLIBCXX_DEBUG. This
commit fixes the test case. The library is unaffected by this change.
Added class hierarchy for user-defined exceptions (#244). Integrated
parse exceptions 101-103. Parse exceptions include the byte count of
the last read character to locate the position of the error (#301).
The constructor basic_json(std::istream&, const parser_callback_t) has
been deprecated since version 2.0.0. This commit removes it together
with its code example, deprecation macro, and test cases. The code now
also compiles with -W-deprecated-declarations.
The library does not preserve the insertion order of object keys. There
are frequent requests to change the library in this aspect. The README
and the contribution guidelines now contain links to containers that
can be used to replace std::map to preserve the insertion order.
Moved all dump()-related functions into a class "serializer". This fix includes a lot of performance improvements yielding a 7% speedup for serialization. Details on the individual steps can be found in the commit messages.
Individual benchmark numbers:
before:
dump jeopardy.json 5 374555228 ns/op
dump jeopardy.json with indent 5 430953700 ns/op
dump numbers/floats.json 5 622938509 ns/op
dump numbers/signed_ints.json 20 82177979 ns/op
after:
dump jeopardy.json 5 335449757 ns/op -11%
dump jeopardy.json with indent 5 375467773 ns/op -13%
dump numbers/floats.json 5 584611852 ns/op -7%
dump numbers/signed_ints.json 20 68289574 ns/op -17%
- Added comments for the serializer class.
- Added test case for resizing of the indentation string.
- Using std::none_of to check if “.0” needs to be added to
floating-point number.
A lot of small changes to avoid memory allocations:
- The locale is only queried once rather than with every number
serialization.
- The indentation string is recycled between different calls.
- The string escape function avoids a copy if no escaping is necessary.
- The string escape and the space function use a complete switch case
instead of cascaded ifs.
Cachegrind measures some 15% performance improvement.
Treated the size of the range as the number of thousand separators.
This logical error yielded a negative value for written_bytes and
eventually an infinite loop, as written_bytes was converted to an
unsigned value.
The class is currently just a wrapper for an std::ostream and collects
all functions related to serialization. The next step should be
recycling of variables to avoid repetitive initialization for each
recursive dump call.
numtostr now directly writes to a stream. Return value of snprintf is
reused to avoid finding end of string. Cachegrind suggests a 1%
performance increase.
All ‘<<‘ calls have been replaced by write()/put() calls. The
indentation strings needs not to be resized. Cachegrind measures 1%
performance improvement.
Indentation string is recycled to avoid allocations. Comma-separation
in objects does not need an if any more. Cachegrind measures 1%
performance improvement.
Added separate code paths for normal output and pritty-printed output.
This allowed to remove most of the ifs along the way. Benchmarks and
cachegrind suggest a 10% performance improvement.
- Add prefix header
- Include catch.hpp
- Include json.hpp
- Replace private with public for all json_unit files
- Move `unit.cpp` to an object library
- cotire issue: strip whitespace from CMAKE_INCLUDE_SYSTEM_FLAG_CXX
This can however not be done easily for value_t, since
external_constructor depends on it, as is operator< which was moved
outside basic_json too.
This is not really an issue, since all basic_json classes share the same
enum
Those warnings are not "fixed", but that's intentional.
Truncations are expected when ArithmeticType is not the same type than
number_unsigned_t (or another basic_json template argument)
only check for public types (iterators, json_pointer)
for private ones (m_array.iterator, primitive_iterator) simply double
parentheses on relevant Catch checks
- fixed a bug that did not discard strings with control characters
between 0x10 and 0x1f
- added termination proofs for two important loops
- made get_ref() constexpr
Instead of copying the test executable and the JSON files used by
the tests at install time, define CMake/CTest tests for running
the json_unit executable from any build directory with the project's
source directory as its working directory.
- call enable_testing in the main lists file to allow the definition
of tests
- remove install commands from the test directory's lists file
- define two tests
- json_unit_default for running the default tests by executing
json_unit without any arguments
- json_unit_all for running all the tests by executing json_unit
with the "*" argument
- update the AppVeyor configuration file to use the new testing method
It's sort of gnarly that it's still doing in-tree builds, but I
really, _really_ don't want to get any more friendly with CMake's
Visual Studio generator to work out how to make it stop doing it.
In-tree builds still work, after all, and the goal of this work is
to make out-of-tree builds work as well. Notional horrors like
this will have to wait ;)
The resulting install tree, when tests are enabled, looks like this:
```
.
├── cmake
│ ├── nlohmann_jsonConfig.cmake
│ ├── nlohmann_jsonConfigVersion.cmake
│ └── nlohmann_jsonTargets.cmake
├── include
│ └── nlohmann
│ └── json.hpp
└── test
├── bin
│ └── json_unit
└── data
├── json_nlohmann_tests
│ ├── all_unicode.json
│ └── bom.json
├── json.org
│ ├── 1.json
│ ├── ...
├── json_roundtrip
│ ├── roundtrip01.json
│ ├── roundtrip02.json
│ └── ...
├── json_tests
│ ├── fail10.json
│ └── ...
└── json_testsuite
└── sample.json
```
It has the property that you can invoke the test binary from the
root of the install tree and the tests work correctly (you no
longer depend on the test binary being run inside the source
tree).
If tests are disabled, the entire `test/` subtree is omitted.
Notice how that yields exactly what you want for using this
library in other projects.
I do not believe I need to update travis due to this change, as the
evil Makefile continues to do in-tree builds. I expect I'll find
out soon enough.
This introduces a clear separation between test data and test
binaries. Test data is moved into test/data, and the test binaries
move into test/src. A new CMake script specific to building the
tests is introduced in /test to slightly clean up the toplevel
one.
As well as tidying things up, this makes the next step trivial...
There exist lots of json libraries, and project/target names must
be globally unique. If someone integrated with this library in a
particularly stupid way, using a generic name like "json" might
cause a problem.
I'm not sure that using a variable for target names really helps
with clarity. Unlike paths, target names aren't really something
you change. In a sense, targets are themselves a sort of variable,
so having a variable to name a variable seems just a bit gnarly.
Generate the config files of the package in CMAKE_CURRENT_BINARY_DIR
instead of CMAKE_BINARY_DIR because the later will refer to the main
project's binary directory if the library is included in the project
using the add_subdirectory command.
- define the project's version in the cmake listfile
- create a config and config version file for the cmake package
- install the json.hpp file and the package's targets, config and
config version files
Define the library as an interface imported library so other targets
can use the library as a dependency and use the interface properties
of the library.
According to the c++11 standard, the declarations are within namespace
scope of the namespace `std'. Add `std::' to avoid unnecessary
requirement of implementations.
Internally, the elements in a map are always sorted by its key following a specific strict weak ordering criterion indicated by its internal comparison object (of type Compare).
With string type, the default comparator is alphabetical order, and thus two come after three.
"make fuzz" creates a simple executable that de-serialises stdin
and re-serialises to stdout.
"make fuzz_testcases" extracts the smaller json test cases into
a testcases directory.
The library can then be fuzzed as follows:
CC=afl-clang-fast make fuzz
make fuzz_testcases
mkdir out
afl-fuzz -i testcases -o out ./fuzz
It was a good idea to implement a const version of operator[] it in the
first place. I was a pity that this implementation was flawed. It was a
mistake to remove the const version completely. This commit
re-introduces the const version. My apologies for all the inconvenience.
STL iterators used by json::iterator don't pass this test in Debug mode.
The test does pass in Release mode, so I felt the best thing to do was selectively disable that test.
This project started as a little excuse to exercise some of the cool new C++11 features. Over time, people actually started to use the JSON library (yey!) and started to help improve it by proposing features, finding bugs, or even fixing my mistakes. I am really [thankful](https://github.com/nlohmann/json/blob/master/README.md#thanks) for this and try to keep track of all the helpers.
To make it as easy as possible for you to contribute and for me to keep an overview, here are a few guidelines which should help us avoid all kinds of unnecessary work or disappointment. And of course, this document is subject to discussion, so please [create an issue](https://github.com/nlohmann/json/issues/new) or a pull request if you find a way to improve it!
## Private reports
Usually, all issues are tracked publicly on [Github](https://github.com/nlohmann/json/issues). If you want to make a private report (e.g., for a vulnerability or to attach an example that is not meant to be publisheed), please send an email to <mail@nlohmann.me>.
## Prerequisites
Please [create an issue](https://github.com/nlohmann/json/issues/new), assuming one does not already exist, and describe your concern. Note you need a [GitHub account](https://github.com/signup/free) for this.
## Describe your issue
Clearly describe the issue:
- If it is a bug, please describe how to **reproduce** it. If possible, attach a complete example which demonstrates the error. Please also state what you **expected** to happen instead of the error.
- If you propose a change or addition, try to give an **example** how the improved code could look like or how to use it.
- If you found a compilation error, please tell us which **compiler** (version and operating system) you used and paste the (relevant part of) the error messages to the ticket.
Please stick to the [issue template](https://github.com/nlohmann/json/blob/develop/.github/ISSUE_TEMPLATE.md) if possible.
## Files to change
There are currently two files which need to be edited:
2. [`test/src/unit-*.cpp`](https://github.com/nlohmann/json/tree/develop/test/src) - These files contain the [Catch](https://github.com/philsquared/Catch) unit tests which currently cover [100 %](https://coveralls.io/github/nlohmann/json) of the library's code.
If you add or change a feature, please also add a unit test to this file. The unit tests can be compiled and executed with
```sh
$ mkdir build
$ cd build
$ cmake ..
$ cmake --build .
$ ctest
```
The test cases are also executed with several different compilers on [Travis](https://travis-ci.org/nlohmann/json) once you open a pull request.
## Note
- If you open a pull request, the code will be automatically tested with [Valgrind](http://valgrind.org)'s Memcheck tool to detect memory leaks. Please be aware that the execution with Valgrind _may_ in rare cases yield different behavior than running the code directly. This can result in failing unit tests which run successfully without Valgrind.
- There is a Makefile target `make pretty` which runs [Artistic Style](http://astyle.sourceforge.net) to fix indentation. If possible, run it before opening the pull request. Otherwise, we shall run it afterward.
## Please don't
- The C++11 support varies between different **compilers** and versions. Please note the [list of supported compilers](https://github.com/nlohmann/json/blob/master/README.md#supported-compilers). Some compilers like GCC 4.8 (and earlier), Clang 3.3 (and earlier), or Microsoft Visual Studio 13.0 and earlier are known not to work due to missing or incomplete C++11 support. Please refrain from proposing changes that work around these compiler's limitations with `#ifdef`s or other means.
- Specifically, I am aware of compilation problems with **Microsoft Visual Studio** (there even is an [issue label](https://github.com/nlohmann/json/issues?utf8=✓&q=label%3A%22visual+studio%22+) for these kind of bugs). I understand that even in 2016, complete C++11 support isn't there yet. But please also understand that I do not want to drop features or uglify the code just to make Microsoft's sub-standard compiler happy. The past has shown that there are ways to express the functionality such that the code compiles with the most recent MSVC - unfortunately, this is not the main objective of the project.
- Please refrain from proposing changes that would **break [JSON](http://json.org) conformance**. If you propose a conformant extension of JSON to be supported by the library, please motivate this extension.
- We shall not extend the library to **support comments**. There is quite some [controversy](https://www.reddit.com/r/programming/comments/4v6chu/why_json_doesnt_support_comments_douglas_crockford/) around this topic, and there were quite some [issues](https://github.com/nlohmann/json/issues/376) on this. We believe that JSON is fine without comments.
- We do not preserve the **insertion order of object elements**. The [JSON standard](https://tools.ietf.org/html/rfc7159.html) defines objects as "an unordered collection of zero or more name/value pairs". To this end, this library does not preserve insertion order of name/value pairs. (In fact, keys will be traversed in alphabetical order as `std::map` with `std::less` is used by default.) Note this behavior conforms to the standard, and we shall not change it to any other order. If you do want to preserve the insertion order, you can specialize the object type with containers like [`tsl::ordered_map`](https://github.com/Tessil/ordered-map) or [`nlohmann::fifo_map`](https://github.com/nlohmann/fifo_map).
- Please do not open pull requests that address **multiple issues**.
## Wanted
The following areas really need contribution:
- Extending the **continuous integration** toward more exotic compilers such as Android NDK, Intel's Compiler, or the bleeding-edge versions of GCC or Clang.
- Improving the efficiency of the **JSON parser**. The current parser is implemented as a naive recursive descent parser with hand coded string handling. More sophisticated approaches like LALR parsers would be really appreciated. That said, parser generators like Bison or ANTLR do not play nice with single-header files -- I really would like to keep the parser inside the `json.hpp` header, and I am not aware of approaches similar to [`re2c`](http://re2c.org) for parsing.
- Extending and updating existing **benchmarks** to include (the most recent version of) this library. Though efficiency is not everything, speed and memory consumption are very important characteristics for C++ developers, so having proper comparisons would be interesting.
[Describe your pull request here. Please read the text below the line, and make sure you follow the checklist.]
* * *
## Pull request checklist
- [ ] Changes are described in the pull request, or an [existing issue is referenced](https://github.com/nlohmann/json/issues).
- [ ] The test suite [compiles and runs](https://github.com/nlohmann/json/blob/develop/README.md#execute-unit-tests) without error.
- [ ] [Code coverage](https://coveralls.io/github/nlohmann/json) is 100%. Test cases can be added by editing the [test suite](https://github.com/nlohmann/json/tree/develop/test/src).
## Please don't
- The C++11 support varies between different **compilers** and versions. Please note the [list of supported compilers](https://github.com/nlohmann/json/blob/master/README.md#supported-compilers). Some compilers like GCC 4.8 (and earlier), Clang 3.3 (and earlier), or Microsoft Visual Studio 13.0 and earlier are known not to work due to missing or incomplete C++11 support. Please refrain from proposing changes that work around these compiler's limitations with `#ifdef`s or other means.
- Specifically, I am aware of compilation problems with **Microsoft Visual Studio** (there even is an [issue label](https://github.com/nlohmann/json/issues?utf8=✓&q=label%3A%22visual+studio%22+) for these kind of bugs). I understand that even in 2016, complete C++11 support isn't there yet. But please also understand that I do not want to drop features or uglify the code just to make Microsoft's sub-standard compiler happy. The past has shown that there are ways to express the functionality such that the code compiles with the most recent MSVC - unfortunately, this is not the main objective of the project.
- Please refrain from proposing changes that would **break [JSON](http://json.org) conformance**. If you propose a conformant extension of JSON to be supported by the library, please motivate this extension.
- Please do not open pull requests that address **multiple issues**.
# Configuration for sentiment-bot - https://github.com/behaviorbot/sentiment-bot
# *Required* toxicity threshold between 0 and .99 with the higher numbers being the most toxic
# Anything higher than this threshold will be marked as toxic and commented on
sentimentBotToxicityThreshold:.7
# *Required* Comment to reply with
sentimentBotReplyComment:>
Please be sure to review the [code of conduct](https://github.com/nlohmann/json/blob/develop/CODE_OF_CONDUCT.md) and be respectful of other users. cc/ @nlohmann
# Configuration for request-info - https://github.com/behaviorbot/request-info
# *Required* Comment to reply with
requestInfoReplyComment:>
We would appreciate it if you could provide us with more info about this issue or pull request! Please check the [issue template](https://github.com/nlohmann/json/blob/develop/.github/ISSUE_TEMPLATE.md) and the [pull request template](https://github.com/nlohmann/json/blob/develop/.github/PULL_REQUEST_TEMPLATE.md).
# *OPTIONAL* Label to be added to Issues and Pull Requests with insufficient information given
In the interest of fostering an open and welcoming environment, we as contributors and maintainers pledge to making participation in our project and our community a harassment-free experience for everyone, regardless of age, body size, disability, ethnicity, gender identity and expression, level of experience, nationality, personal appearance, race, religion, or sexual identity and orientation.
## Our Standards
Examples of behavior that contributes to creating a positive environment include:
* Using welcoming and inclusive language
* Being respectful of differing viewpoints and experiences
* Gracefully accepting constructive criticism
* Focusing on what is best for the community
* Showing empathy towards other community members
Examples of unacceptable behavior by participants include:
* The use of sexualized language or imagery and unwelcome sexual attention or advances
* Trolling, insulting/derogatory comments, and personal or political attacks
* Public or private harassment
* Publishing others' private information, such as a physical or electronic address, without explicit permission
* Other conduct which could reasonably be considered inappropriate in a professional setting
## Our Responsibilities
Project maintainers are responsible for clarifying the standards of acceptable behavior and are expected to take appropriate and fair corrective action in response to any instances of unacceptable behavior.
Project maintainers have the right and responsibility to remove, edit, or reject comments, commits, code, wiki edits, issues, and other contributions that are not aligned to this Code of Conduct, or to ban temporarily or permanently any contributor for other behaviors that they deem inappropriate, threatening, offensive, or harmful.
## Scope
This Code of Conduct applies both within project spaces and in public spaces when an individual is representing the project or its community. Examples of representing a project or community include using an official project e-mail address, posting via an official social media account, or acting as an appointed representative at an online or offline event. Representation of a project may be further defined and clarified by project maintainers.
## Enforcement
Instances of abusive, harassing, or otherwise unacceptable behavior may be reported by contacting the project team at mail@nlohmann.me. The project team will review and investigate all complaints, and will respond in a way that it deems appropriate to the circumstances. The project team is obligated to maintain confidentiality with regard to the reporter of an incident. Further details of specific enforcement policies may be posted separately.
Project maintainers who do not follow or enforce the Code of Conduct in good faith may face temporary or permanent repercussions as determined by other members of the project's leadership.
## Attribution
This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4, available at [http://contributor-covenant.org/version/1/4][version]
- std::map\<std::string, std::string\> from json object yields C2665: 'std::pair\<const \_Kty,\_Ty\>::pair': none of the 2 overloads could convert all the argument types [\#827](https://github.com/nlohmann/json/issues/827)
- object.dump gives quoted string, want to use .dump\(\) to generate javascripts. [\#826](https://github.com/nlohmann/json/issues/826)
- Assertion failed on \["NoExistKey"\] of an not existing key of const json& [\#825](https://github.com/nlohmann/json/issues/825)
- vs2015 error : static member will remain uninitialized at runtime but use in constant-expressions is supported [\#824](https://github.com/nlohmann/json/issues/824)
- Code Checking Warnings from json.hpp on VS2017 Community [\#821](https://github.com/nlohmann/json/issues/821)
- Missing iostream in try online [\#820](https://github.com/nlohmann/json/issues/820)
- Floating point value loses decimal point during dump [\#818](https://github.com/nlohmann/json/issues/818)
- Conan package for the library [\#817](https://github.com/nlohmann/json/issues/817)
- Proposal: out\_of\_range should be a subclass of std::out\_of\_range [\#756](https://github.com/nlohmann/json/issues/756)
- Compiling with icpc [\#755](https://github.com/nlohmann/json/issues/755)
- Getter is setting the value to null if the key does not exist [\#754](https://github.com/nlohmann/json/issues/754)
- parsing works sometimes and crashes others [\#752](https://github.com/nlohmann/json/issues/752)
- Static\_assert failed "incompatible pointer type" with Xcode [\#751](https://github.com/nlohmann/json/issues/751)
- user-defined literal operator not found [\#750](https://github.com/nlohmann/json/issues/750)
- getting clean string from it.key\(\) [\#748](https://github.com/nlohmann/json/issues/748)
- Best method for exploring and obtaining values of nested json objects when the names are not known beforehand? [\#747](https://github.com/nlohmann/json/issues/747)
- null char at the end of string [\#746](https://github.com/nlohmann/json/issues/746)
- Incorrect sample for operator \>\> in docs [\#745](https://github.com/nlohmann/json/issues/745)
- How to construct an iteratable usage in nlohmann json? [\#636](https://github.com/nlohmann/json/issues/636)
- \[Question\] copy assign json-container to vector [\#635](https://github.com/nlohmann/json/issues/635)
- Get size without .dump\(\) [\#634](https://github.com/nlohmann/json/issues/634)
- Segmentation fault when parsing invalid json file [\#633](https://github.com/nlohmann/json/issues/633)
- How to serialize from json to vector\<customType\>? [\#632](https://github.com/nlohmann/json/issues/632)
- no member named 'thousands\_sep' in 'lconv' [\#631](https://github.com/nlohmann/json/issues/631)
- \[Question\] Any fork for \(the unsupported\) Visual Studio 2012 version? [\#628](https://github.com/nlohmann/json/issues/628)
- Dependency injection in serializer [\#627](https://github.com/nlohmann/json/issues/627)
- from\_json for std::array [\#625](https://github.com/nlohmann/json/issues/625)
- Discussion: How to structure the parsing function families [\#623](https://github.com/nlohmann/json/issues/623)
- Question: How to erase subtree [\#622](https://github.com/nlohmann/json/issues/622)
- Insertion into nested json field [\#621](https://github.com/nlohmann/json/issues/621)
- \[Question\] When using this as git submodule, will it clone the whole thing include test data and benchmark? [\#620](https://github.com/nlohmann/json/issues/620)
- Question: return static json object from function [\#618](https://github.com/nlohmann/json/issues/618)
- \[-Wdeprecated-declarations\] in row `j \>\> ss;` in file `json.hpp:7405:26` and FAILED unit tests with MinGWx64! [\#616](https://github.com/nlohmann/json/issues/616)
- to\_json for pairs, tuples [\#614](https://github.com/nlohmann/json/issues/614)
- Using uninitialized memory 'buf' in line 11173 v2.1.1? [\#613](https://github.com/nlohmann/json/issues/613)
- How to parse multiple same Keys of JSON and save them? [\#612](https://github.com/nlohmann/json/issues/612)
- "Multiple declarations" error when using types defined with `typedef` [\#611](https://github.com/nlohmann/json/issues/611)
- 2.1.1+ breaks compilation of shared\_ptr\<json\> == 0 [\#610](https://github.com/nlohmann/json/issues/610)
- a bug of inheritance ? [\#608](https://github.com/nlohmann/json/issues/608)
- std::map key conversion with to\_json [\#607](https://github.com/nlohmann/json/issues/607)
- json.hpp:6384:62: error: wrong number of template arguments \(1, should be 2\) [\#606](https://github.com/nlohmann/json/issues/606)
- Incremental parsing: Where's the push version? [\#605](https://github.com/nlohmann/json/issues/605)
- Is there a way to validate the structure of a json object ? [\#604](https://github.com/nlohmann/json/issues/604)
- \[Question\] Issue when using Appveyor when compiling library [\#603](https://github.com/nlohmann/json/issues/603)
- BOM not skipped when using json:parse\(iterator\) [\#602](https://github.com/nlohmann/json/issues/602)
- Use of the binary type in CBOR and Message Pack [\#601](https://github.com/nlohmann/json/issues/601)
- Newbie issue: how does one convert a map in Json back to std::map? [\#600](https://github.com/nlohmann/json/issues/600)
- Plugin system [\#599](https://github.com/nlohmann/json/issues/599)
- NaN to json and back [\#515](https://github.com/nlohmann/json/issues/515)
- Comparison of NaN [\#514](https://github.com/nlohmann/json/issues/514)
- why it's not possible to serialize c++11 enums directly [\#513](https://github.com/nlohmann/json/issues/513)
- clang compile error: use of overloaded operator '\<=' is ambiguous with \(nlohmann::json{{"a", 5}}\)\["a"\] \<= 10 [\#512](https://github.com/nlohmann/json/issues/512)
- Why not also look inside the type for \(static\) to\_json and from\_json funtions? [\#511](https://github.com/nlohmann/json/issues/511)
- :boom: throwing an exception in case dump encounters a non-UTF-8 string \#838 [\#870](https://github.com/nlohmann/json/pull/870) ([nlohmann](https://github.com/nlohmann))
- cmake: use BUILD\_INTERFACE/INSTALL\_INTERFACE [\#855](https://github.com/nlohmann/json/pull/855) ([theodelrieu](https://github.com/theodelrieu))
- to/from\_json: add a MSVC-specific static\_assert to force a stacktrace [\#854](https://github.com/nlohmann/json/pull/854) ([theodelrieu](https://github.com/theodelrieu))
- Add .natvis for MSVC debug view [\#844](https://github.com/nlohmann/json/pull/844) ([TinyTinni](https://github.com/TinyTinni))
- add forwarding references to json\_ref constructor [\#807](https://github.com/nlohmann/json/pull/807) ([theodelrieu](https://github.com/theodelrieu))
- Add transparent comparator and perfect forwarding support to find\(\) and count\(\) [\#795](https://github.com/nlohmann/json/pull/795) ([jseward](https://github.com/jseward))
- Error : 'identifier "size\_t" is undefined' in linux [\#793](https://github.com/nlohmann/json/pull/793) ([sonulohani](https://github.com/sonulohani))
- Fix Visual Studio 2017 warnings [\#788](https://github.com/nlohmann/json/pull/788) ([jseward](https://github.com/jseward))
- Fix warning C4706 on Visual Studio 2017 [\#785](https://github.com/nlohmann/json/pull/785) ([jseward](https://github.com/jseward))
- Set GENERATE\_TAGFILE in Doxyfile [\#783](https://github.com/nlohmann/json/pull/783) ([eld00d](https://github.com/eld00d))
- using more CMake [\#765](https://github.com/nlohmann/json/pull/765) ([nlohmann](https://github.com/nlohmann))
- Fix "not constraint" grammar in docs [\#674](https://github.com/nlohmann/json/pull/674) ([wincent](https://github.com/wincent))
- Add documentation for integration with CMake and hunter [\#671](https://github.com/nlohmann/json/pull/671) ([dan-42](https://github.com/dan-42))
- REFACTOR: rewrite CMakeLists.txt for better inlcude and reuse [\#669](https://github.com/nlohmann/json/pull/669) ([dan-42](https://github.com/dan-42))
- enable\_testing only if the JSON\_BuildTests is ON [\#666](https://github.com/nlohmann/json/pull/666) ([effolkronium](https://github.com/effolkronium))
- Support moving from rvalues in std::initializer\_list [\#663](https://github.com/nlohmann/json/pull/663) ([himikof](https://github.com/himikof))
- add ensure\_ascii parameter to dump. \#330 [\#654](https://github.com/nlohmann/json/pull/654) ([ryanjmulder](https://github.com/ryanjmulder))
- Rename BuildTests to JSON\_BuildTests [\#652](https://github.com/nlohmann/json/pull/652) ([olegendo](https://github.com/olegendo))
- Don't include \<iostream\>, use std::make\_shared [\#650](https://github.com/nlohmann/json/pull/650) ([olegendo](https://github.com/olegendo))
- \#550 Fix iterator related compiling issues for Intel icc [\#598](https://github.com/nlohmann/json/pull/598) ([HenryRLee](https://github.com/HenryRLee))
- Issue \#593 Fix the arithmetic operators in the iterator and reverse iterator [\#595](https://github.com/nlohmann/json/pull/595) ([HenryRLee](https://github.com/HenryRLee))
- fix doxygen error of basic\_json::get\(\) [\#583](https://github.com/nlohmann/json/pull/583) ([zhaohuaxishi](https://github.com/zhaohuaxishi))
- Fixing assignement for iterator wrapper second, and adding unit test [\#579](https://github.com/nlohmann/json/pull/579) ([Type1J](https://github.com/Type1J))
- Adding first and second properties to iteration\_proxy\_internal [\#578](https://github.com/nlohmann/json/pull/578) ([Type1J](https://github.com/Type1J))
- Adding support for Meson. [\#576](https://github.com/nlohmann/json/pull/576) ([Type1J](https://github.com/Type1J))
- add enum class default conversions [\#545](https://github.com/nlohmann/json/pull/545) ([theodelrieu](https://github.com/theodelrieu))
- Properly pop diagnostics [\#540](https://github.com/nlohmann/json/pull/540) ([tinloaf](https://github.com/tinloaf))
- Add Visual Studio 17 image to appveyor build matrix [\#536](https://github.com/nlohmann/json/pull/536) ([vpetrigo](https://github.com/vpetrigo))
- Make exception base class visible in basic\_json [\#526](https://github.com/nlohmann/json/pull/526) ([krzysztofwos](https://github.com/krzysztofwos))
- :art: Namespace `uint8\_t` from the C++ stdlib [\#510](https://github.com/nlohmann/json/pull/510) ([alex-weej](https://github.com/alex-weej))
- add to\_json method for C arrays [\#508](https://github.com/nlohmann/json/pull/508) ([theodelrieu](https://github.com/theodelrieu))
- Parsing of floats locale dependent [\#302](https://github.com/nlohmann/json/issues/302)
- Speedup CI builds using cotire [\#461](https://github.com/nlohmann/json/pull/461) ([tusharpm](https://github.com/tusharpm))
- TurpentineDistillery feature/locale independent str to num [\#450](https://github.com/nlohmann/json/pull/450) ([nlohmann](https://github.com/nlohmann))
- README: adjust boost::optional example [\#439](https://github.com/nlohmann/json/pull/439) ([jaredgrubb](https://github.com/jaredgrubb))
- fix \#414 - comparing to 0 literal [\#415](https://github.com/nlohmann/json/pull/415) ([stanmihai4](https://github.com/stanmihai4))
- Replace class iterator and const\_iterator by using a single template class to reduce code. [\#395](https://github.com/nlohmann/json/pull/395) ([Bosswestfalen](https://github.com/Bosswestfalen))
- Clang: quiet a warning [\#391](https://github.com/nlohmann/json/pull/391) ([jaredgrubb](https://github.com/jaredgrubb))
- Fix issue \#380: Signed integer overflow check [\#390](https://github.com/nlohmann/json/pull/390) ([qwename](https://github.com/qwename))
- can function dump\(\) return string in the order I push in the json object ? [\#286](https://github.com/nlohmann/json/issues/286)
- Error on the Mac: Undefined symbols for architecture x86\_64 [\#285](https://github.com/nlohmann/json/issues/285)
- value\(\) does not work with \_json\_pointer types [\#283](https://github.com/nlohmann/json/issues/283)
- Build error for std::int64 [\#282](https://github.com/nlohmann/json/issues/282)
- strings can't be accessed after dump\(\)-\>parse\(\) - type is lost [\#281](https://github.com/nlohmann/json/issues/281)
- Easy serialization of classes [\#280](https://github.com/nlohmann/json/issues/280)
- recursive data structures [\#277](https://github.com/nlohmann/json/issues/277)
- hexify\(\) function emits conversion warning [\#270](https://github.com/nlohmann/json/issues/270)
- let the makefile choose the correct sed [\#279](https://github.com/nlohmann/json/pull/279) ([murinicanor](https://github.com/murinicanor))
- Update hexify to use array lookup instead of ternary \(\#270\) [\#275](https://github.com/nlohmann/json/pull/275) ([dtoma](https://github.com/dtoma))
- .get\<std::string\>\(\) works for non spaced string but returns as array for spaced/longer strings [\#236](https://github.com/nlohmann/json/issues/236)
- ambiguous overload for 'push\_back' and 'operator+=' [\#235](https://github.com/nlohmann/json/issues/235)
- Can't use basic\_json::iterator as a base iterator for std::move\_iterator [\#233](https://github.com/nlohmann/json/issues/233)
- json object's creation can freezes execution [\#231](https://github.com/nlohmann/json/issues/231)
- Incorrect dumping of parsed numbers with exponents, but without decimal places [\#230](https://github.com/nlohmann/json/issues/230)
- double values are serialized with commas as decimal points [\#228](https://github.com/nlohmann/json/issues/228)
- Move semantics with std::initializer\_list [\#225](https://github.com/nlohmann/json/issues/225)
- abort during getline in yyfill [\#223](https://github.com/nlohmann/json/issues/223)
- free\(\): invalid pointer error in GCC 5.2.1 [\#221](https://github.com/nlohmann/json/issues/221)
- Error compile Android NDK error: 'strtof' is not a member of 'std' [\#219](https://github.com/nlohmann/json/issues/219)
- Wrong link in the README.md [\#217](https://github.com/nlohmann/json/issues/217)
- Wide character strings not supported [\#216](https://github.com/nlohmann/json/issues/216)
- Memory allocations using range-based for loops [\#214](https://github.com/nlohmann/json/issues/214)
- would you like to support gcc 4.8.1? [\#211](https://github.com/nlohmann/json/issues/211)
- Reading concatenated json's from an istream [\#210](https://github.com/nlohmann/json/issues/210)
- Conflicting typedef of ssize\_t on Windows 32 bit when using Boost.Python [\#204](https://github.com/nlohmann/json/issues/204)
- Inconsistency between operator\[\] and push\_back [\#203](https://github.com/nlohmann/json/issues/203)
- Small bugs in json.hpp \(get\_number\) and unit.cpp \(non-standard integer type test\) [\#199](https://github.com/nlohmann/json/issues/199)
- GCC/clang floating point parsing bug in strtod\(\) [\#195](https://github.com/nlohmann/json/issues/195)
- What is within scope? [\#192](https://github.com/nlohmann/json/issues/192)
- Bugs in miloyip/nativejson-benchmark: roundtrips [\#187](https://github.com/nlohmann/json/issues/187)
- Floating point exceptions [\#181](https://github.com/nlohmann/json/issues/181)
- Integer conversion to unsigned [\#178](https://github.com/nlohmann/json/issues/178)
- map string string fails to compile [\#176](https://github.com/nlohmann/json/issues/176)
- In basic\_json::basic\_json\(const CompatibleArrayType& val\), the requirement of CompatibleArrayType is not strict enough. [\#174](https://github.com/nlohmann/json/issues/174)
- Provide a FAQ [\#163](https://github.com/nlohmann/json/issues/163)
- Implicit assignment to std::string fails [\#144](https://github.com/nlohmann/json/issues/144)
- Out of tree builds and a few other miscellaneous CMake cleanups. [\#242](https://github.com/nlohmann/json/pull/242) ([ChrisKitching](https://github.com/ChrisKitching))
- Add support for afl-fuzz testing [\#207](https://github.com/nlohmann/json/pull/207) ([mykter](https://github.com/mykter))
- replaced ssize\_t occurrences with auto \(addresses \#204\) [\#205](https://github.com/nlohmann/json/pull/205) ([nlohmann](https://github.com/nlohmann))
- Fixed issue \#199 - Small bugs in json.hpp \(get\_number\) and unit.cpp \(non-standard integer type test\) [\#200](https://github.com/nlohmann/json/pull/200) ([twelsby](https://github.com/twelsby))
- Fix broken link [\#197](https://github.com/nlohmann/json/pull/197) ([vog](https://github.com/vog))
- Issue \#195 - update Travis to Trusty due to gcc/clang strtod\(\) bug [\#196](https://github.com/nlohmann/json/pull/196) ([twelsby](https://github.com/twelsby))
- Issue \#178 - Extending support to full uint64\_t/int64\_t range and unsigned type \(updated\) [\#193](https://github.com/nlohmann/json/pull/193) ([twelsby](https://github.com/twelsby))
- Question about get\_ref\(\) [\#128](https://github.com/nlohmann/json/issues/128)
- range based for loop for objects [\#83](https://github.com/nlohmann/json/issues/83)
- Consider submitting this to the Boost Library Incubator [\#66](https://github.com/nlohmann/json/issues/66)
- Fixed Issue \#186 - add strto\(f|d|ld\) overload wrappers, "-0.0" special case and FP trailing zero [\#191](https://github.com/nlohmann/json/pull/191) ([twelsby](https://github.com/twelsby))
- Issue \#185 - remove approx\(\) and use \#pragma to kill warnings [\#190](https://github.com/nlohmann/json/pull/190) ([twelsby](https://github.com/twelsby))
- Fixed Issue \#171 - added two extra template overloads of operator\[\] for T\* arguments [\#189](https://github.com/nlohmann/json/pull/189) ([twelsby](https://github.com/twelsby))
- add key name to exception [\#160](https://github.com/nlohmann/json/issues/160)
- Getting member discarding qualifyer [\#159](https://github.com/nlohmann/json/issues/159)
- basic\_json::iterator::value\(\) output includes quotes while basic\_json::iterator::key\(\) doesn't [\#158](https://github.com/nlohmann/json/issues/158)
- Indexing `const basic\_json\<\>` with `const basic\_string\<char\>` [\#157](https://github.com/nlohmann/json/issues/157)
- token\_type\_name\(token\_type t\): not all control paths return a value [\#156](https://github.com/nlohmann/json/issues/156)
- prevent json.hpp from emitting compiler warnings [\#154](https://github.com/nlohmann/json/issues/154)
- json::parse\(string\) does not check utf8 bom [\#152](https://github.com/nlohmann/json/issues/152)
- unsigned 64bit values output as signed [\#151](https://github.com/nlohmann/json/issues/151)
- Unable to compile on MSVC 2015 with SDL checking enabled: This function or variable may be unsafe. [\#149](https://github.com/nlohmann/json/issues/149)
- "Json Object" type does not keep object order [\#148](https://github.com/nlohmann/json/issues/148)
- dump\(\) convert strings encoded by utf-8 to shift-jis on windows 10. [\#147](https://github.com/nlohmann/json/issues/147)
- Unable to get field names in a json object [\#145](https://github.com/nlohmann/json/issues/145)
- Question: Is the use of incomplete type correct? [\#138](https://github.com/nlohmann/json/issues/138)
- json.hpp:5746:32: error: 'to\_string' is not a member of 'std' [\#136](https://github.com/nlohmann/json/issues/136)
- Bug in basic\_json::operator\[\] const overload [\#135](https://github.com/nlohmann/json/issues/135)
- wrong enable\_if for const pointer \(instead of pointer-to-const\) [\#134](https://github.com/nlohmann/json/issues/134)
- overload of at\(\) with default value [\#133](https://github.com/nlohmann/json/issues/133)
- disabled "CopyAssignable" test for MSVC in Debug mode, see \#125 [\#131](https://github.com/nlohmann/json/pull/131) ([dariomt](https://github.com/dariomt))
- removed stream operator for iterator, resolution for \#125 [\#130](https://github.com/nlohmann/json/pull/130) ([dariomt](https://github.com/dariomt))
- fixed typos in comments for examples [\#129](https://github.com/nlohmann/json/pull/129) ([dariomt](https://github.com/dariomt))
- move code into namespace [\#9](https://github.com/nlohmann/json/issues/9)
- free functions for explicit objects and arrays in initializer lists [\#8](https://github.com/nlohmann/json/issues/8)
- unique\_ptr for ownership [\#7](https://github.com/nlohmann/json/issues/7)
- Add unit tests [\#4](https://github.com/nlohmann/json/issues/4)
- Drop C++98 support [\#3](https://github.com/nlohmann/json/issues/3)
- Test case coverage [\#2](https://github.com/nlohmann/json/issues/2)
- Runtime error in Travis job [\#1](https://github.com/nlohmann/json/issues/1)
- Keyword 'inline' is useless when member functions are defined in headers [\#87](https://github.com/nlohmann/json/pull/87) ([ahamez](https://github.com/ahamez))
- Replace `default\_callback` function with `nullptr` and check for null… [\#72](https://github.com/nlohmann/json/pull/72) ([aburgh](https://github.com/aburgh))
- support enum [\#71](https://github.com/nlohmann/json/pull/71) ([likebeta](https://github.com/likebeta))
- Fix performance regression introduced with the parsing callback feature. [\#69](https://github.com/nlohmann/json/pull/69) ([aburgh](https://github.com/aburgh))
- Improve the implementations of the comparission-operators [\#63](https://github.com/nlohmann/json/pull/63) ([Florianjw](https://github.com/Florianjw))
- Fix compilation of json\_unit with GCC 5 [\#59](https://github.com/nlohmann/json/pull/59) ([dkopecek](https://github.com/dkopecek))
- template version with re2c scanner [\#36](https://github.com/nlohmann/json/pull/36) ([nlohmann](https://github.com/nlohmann))
- more descriptive documentation in example [\#33](https://github.com/nlohmann/json/pull/33) ([luxe](https://github.com/luxe))
- Fix string conversion under Clang [\#26](https://github.com/nlohmann/json/pull/26) ([wancw](https://github.com/wancw))
- Fixed dumping of strings [\#24](https://github.com/nlohmann/json/pull/24) ([Teemperor](https://github.com/Teemperor))
- Added a remark to the readme that coverage is GCC only for now [\#23](https://github.com/nlohmann/json/pull/23) ([Teemperor](https://github.com/Teemperor))
- Implemented the JSON spec for string parsing for everything but the \uXXXX escaping [\#21](https://github.com/nlohmann/json/pull/21) ([Teemperor](https://github.com/Teemperor))
- add the std iterator typedefs to iterator and const\_iterator [\#19](https://github.com/nlohmann/json/pull/19) ([kirkshoop](https://github.com/kirkshoop))
gsed -i '2i All notable changes to this project will be documented in this file. This project adheres to [Semantic Versioning](http://semver.org/).' ChangeLog.md
[](http://isitmaintained.com/project/nlohmann/json "Average time to resolve an issue")
[](https://bestpractices.coreinfrastructure.org/projects/289)
- [Design goals](#design-goals)
- [Integration](#integration)
- [Examples](#examples)
- [JSON as first-class data type](#json-as-first-class-data-type)
- [Projects using JSON for Modern C++](#projects-using-json-for-modern-c)
- [Notes](#notes)
- [Execute unit tests](#execute-unit-tests)
## Design goals
There are myriads of [JSON](http://json.org) libraries out there, and each may even have its reason to exist. Our class had these design goals:
- **Intuitive syntax**. In languages such as Python, JSON feels like a first class data type. We used all the operator magic of modern C++ to achieve the same feeling in your code. Check out the [examples below](#examples) and you know, what I mean.
- **Intuitive syntax**. In languages such as Python, JSON feels like a first class data type. We used all the operator magic of modern C++ to achieve the same feeling in your code. Check out the [examples below](#examples) and you'll know what I mean.
- **Trivial integration**. Our whole code consists of a single header file `json.hpp`. That's it. No library, no subproject, no dependencies, no complex build system. The class is written in vanilla C++11. All in all, everything should require no adjustment of your compiler flags or project settings.
- **Trivial integration**. Our whole code consists of a single header file [`json.hpp`](https://github.com/nlohmann/json/blob/develop/src/json.hpp). That's it. No library, no subproject, no dependencies, no complex build system. The class is written in vanilla C++11. All in all, everything should require no adjustment of your compiler flags or project settings.
- **Serious testing**. Our class is heavily [unit-tested](https://github.com/nlohmann/json/blob/master/test/json_unit.cc) and covers [100%](https://coveralls.io/r/nlohmann/json) of the code, including all exceptional behavior. Furthermore, we checked with [Valgrind](http://valgrind.org) that there are no memory leaks.
- **Serious testing**. Our class is heavily [unit-tested](https://github.com/nlohmann/json/blob/master/test/src/unit.cpp) and covers [100%](https://coveralls.io/r/nlohmann/json) of the code, including all exceptional behavior. Furthermore, we checked with [Valgrind](http://valgrind.org) that there are no memory leaks. To maintain high quality, the project is following the [Core Infrastructure Initiative (CII) best practices](https://bestpractices.coreinfrastructure.org/projects/289).
Other aspects were not so important to us:
- **Memory efficiency**. Each JSON object has an overhead of one pointer (the maximal size of a union) and one enumeration element (1 byte). The default generalization uses the following C++ data types: `std::string` for strings, `int64_t` or `double` for numbers, `std::map` for objects, `std::vector` for arrays, and `bool` for Booleans. However, you can template the generalized class `basic_json` to your needs.
- **Memory efficiency**. Each JSON object has an overhead of one pointer (the maximal size of a union) and one enumeration element (1 byte). The default generalization uses the following C++ data types: `std::string` for strings, `int64_t`, `uint64_t` or `double` for numbers, `std::map` for objects, `std::vector` for arrays, and `bool` for Booleans. However, you can template the generalized class `basic_json` to your needs.
- **Speed**. There are certainly [faster JSON libraries](https://github.com/miloyip/nativejson-benchmark#parsing-time) out there. However, if your goal is to speed up your development by adding JSON support with a single header, then this library is the way to go. If you know how to use a `std::vector` or `std::map`, you are already set.
See the [contribution guidelines](https://github.com/nlohmann/json/blob/master/.github/CONTRIBUTING.md#please-dont) for more information.
- **Speed**. We currently implement the parser as naive [recursive descent parser](http://en.wikipedia.org/wiki/Recursive_descent_parser) with hand coded string handling. It is fast enough, but a [LALR-parser](http://en.wikipedia.org/wiki/LALR_parser) with a decent regular expression processor should be even faster (but would consist of more files which makes the integration harder).
## Integration
@@ -38,18 +65,23 @@ using json = nlohmann::json;
to the files you want to use JSON objects. That's it. Do not forget to set the necessary switches to enable C++11 (e.g., `-std=c++11` for GCC and Clang).
## Supported compilers
:beer: If you are using OS X and [Homebrew](http://brew.sh), just type `brew tap nlohmann/json` and `brew install nlohmann_json` and you're set. If you want the bleeding edge rather than the latest release, use `brew install nlohmann_json --HEAD`.
Though it's 2015 already, the support for C++11 is still a bit sparse. Currently, the following compilers are known to work:
If you are using the [Meson Build System](http://mesonbuild.com), then you can wrap this repo as a subproject.
- GCC 4.8 - 5.2
- Clang 3.4 - 3.7
- Microsoft Visual C++ 14.0 RC
If you are using [Conan](https://www.conan.io/) to manage your dependencies, merely add `jsonformoderncpp/x.y.z@vthiery/stable` to your `conanfile.py`'s requires, where `x.y.z` is the release version you want to use. Please file issues [here](https://github.com/vthiery/conan-jsonformoderncpp/issues) if you experience problems with the packages.
If you are using [hunter](https://github.com/ruslo/hunter/) on your project for external dependencies, then you can use the [nlohmann_json package](https://docs.hunter.sh/en/latest/packages/pkg/nlohmann_json.html). Please see the hunter project for any issues regarding the packaging.
If you are using [vcpkg](https://github.com/Microsoft/vcpkg/) on your project for external dependencies, then you can use the [nlohmann-json package](https://github.com/Microsoft/vcpkg/tree/master/ports/nlohmann-json). Please see the vcpkg project for any issues regarding the packaging.
I would be happy to learn about other compilers/versions.
## Examples
Beside the examples below, you may want to check the [documentation](https://nlohmann.github.io/json/) where each function contains a separate code example (e.g., check out [`emplace()`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a602f275f0359ab181221384989810604.html#a602f275f0359ab181221384989810604)). All [example files](https://github.com/nlohmann/json/tree/develop/doc/examples) can be compiled and executed on their own (e.g., file [emplace.cpp](https://github.com/nlohmann/json/blob/develop/doc/examples/emplace.cpp)).
### JSON as first-class data type
Here are some examples to give you an idea how to use the class.
You can create an object (deserialization) by appending `_json` to a string literal:
```cpp
// create object from string literal
jsonj="{ \"happy\": true, \"pi\": 3.141 }"_json;
// or even nicer (thanks http://isocpp.org/blog/2015/01/json-for-modern-cpp)
// or even nicer with a raw string literal
autoj2=R"(
{
"happy":true,
"pi":3.141
}
)"_json;
```
// or explicitly
Note that without appending the `_json` suffix, the passed string literal is not parsed, but just used as JSON string value. That is, `json j = "{ \"happy\": true, \"pi\": 3.141 }"` would just store the string `"{ "happy": true, "pi": 3.141 }"` rather than parsing the actual object.
The above example can also be expressed explicitly using `json::parse()`:
`.dump()` always returns the serialized value, and `.get<std::string>()` returns the originally stored string value.
#### To/from streams (e.g. files, string streams)
You can also use streams to serialize and deserialize:
```cpp
// deserialize from standard input
jsonj;
j<<std::cin;
std::cin>>j;
// serialize to standard output
std::cout<<j;
@@ -178,7 +244,37 @@ std::cout << j;
std::cout<<std::setw(4)<<j<<std::endl;
```
These operators work for any subclasses of `std::istream` or `std::ostream`.
These operators work for any subclasses of `std::istream` or `std::ostream`. Here is the same example with files:
```cpp
// read a JSON file
std::ifstreami("file.json");
jsonj;
i>>j;
// write prettified JSON to another file
std::ofstreamo("pretty.json");
o<<std::setw(4)<<j<<std::endl;
```
Please note that setting the exception bit for `failbit` is inappropriate for this use case. It will result in program termination due to the `noexcept` specifier in use.
#### Read from iterator range
You can also read JSON from an iterator range; that is, from any container accessible by iterators whose content is stored as contiguous byte sequence, for instance a `std::vector<std::uint8_t>`:
```cpp
std::vector<std::uint8_t>v={'t','r','u','e'};
jsonj=json::parse(v.begin(),v.end());
```
You may leave the iterators for the range [begin, end):
```cpp
std::vector<std::uint8_t> v = {'t', 'r', 'u', 'e'};
json j = json::parse(v);
```
### STL-like access
@@ -191,13 +287,16 @@ j.push_back("foo");
j.push_back(1);
j.push_back(true);
// also use emplace_back
j.emplace_back(1.78);
// iterate the array
for(json::iteratorit=j.begin();it!=j.end();++it){
std::cout<<*it<<'\n';
}
// range-based for
for(autoelement:j){
for(auto&element:j){
std::cout<<element<<'\n';
}
@@ -206,6 +305,9 @@ const std::string tmp = j[0];
j[1]=42;
boolfoo=j.at(2);
// comparison
j=="[\"foo\", 1, true]"_json;// true
// other stuff
j.size();// 3 entries
j.empty();// false
@@ -220,15 +322,15 @@ j.is_object();
j.is_array();
j.is_string();
// comparison
j=="[\"foo\", 1, true]"_json;// true
// create an object
jsono;
o["foo"]=23;
o["bar"]=false;
o["baz"]=3.141;
// also use emplace
o.emplace("weather","sunny");
// special iterator member functions for objects
for(json::iteratorit=o.begin();it!=o.end();++it){
std::cout<<it.key()<<" : "<<it.value()<<"\n";
@@ -247,9 +349,10 @@ int fob_present = o.count("fob"); // 0
o.erase("foo");
```
### Conversion from STL containers
Any sequence container (`std::array`, `std::vector`, `std::deque`, `std::forward_list`, `std::list`) whose values can be used to construct JSON types (e.g., integers, floating point numbers, Booleans, string types, or again STL containers described in this section) can be used to create a JSON array. The same holds for similar associative containers (`std::set`, `std::multiset`, `std::unordered_set`, `std::unordered_multiset`), but in these cases the order of the elements of the array depends how the elements are ordered in the respective STL container.
Any sequence container (`std::array`, `std::vector`, `std::deque`, `std::forward_list`, `std::list`) whose values can be used to construct JSON types (e.g., integers, floating point numbers, Booleans, string types, or again STL containers described in this section) can be used to create a JSON array. The same holds for similar associative containers (`std::set`, `std::multiset`, `std::unordered_set`, `std::unordered_multiset`), but in these cases the order of the elements of the array depends on how the elements are ordered in the respective STL container.
```cpp
std::vector<int>c_vector{1,2,3,4};
@@ -281,20 +384,20 @@ json j_uset(c_uset); // only one entry for "one" is used
jsonj_umset(c_umset);// both entries for "one" are used
// maybe ["one", "two", "one", "four"]
```
Likewise, any associative key-value containers (`std::map`, `std::multimap`, `std::unordered_map`, `std::unordered_multimap`) whose keys are can construct an `std::string` and whose values can be used to construct JSON types (see examples above) can be used to to create a JSON object. Note that in case of multimaps only one key is used in the JSON object and the value depends on the internal order of the STL container.
Likewise, any associative key-value containers (`std::map`, `std::multimap`, `std::unordered_map`, `std::unordered_multimap`) whose keys can construct an `std::string` and whose values can be used to construct JSON types (see examples above) can be used to create a JSON object. Note that in case of multimaps only one key is used in the JSON object and the value depends on the internal order of the STL container.
The library supports **JSON Pointer** ([RFC 6901](https://tools.ietf.org/html/rfc6901)) as alternative means to address structured values. On top of this, **JSON Patch** ([RFC 6902](https://tools.ietf.org/html/rfc6902)) allows to describe differences between two JSON values - effectively allowing patch and diff operations known from Unix.
That's all! When calling the `json` constructor with your type, your custom `to_json` method will be automatically called.
Likewise, when calling `get<your_type>()`, the `from_json` method will be called.
Some important things:
* Those methods **MUST** be in your type's namespace (which can be the global namespace), or the library will not be able to locate them (in this example, they are in namespace `ns`, where `person` is defined).
* When using `get<your_type>()`, `your_type`**MUST** be [DefaultConstructible](http://en.cppreference.com/w/cpp/concept/DefaultConstructible). (There is a way to bypass this requirement described later.)
* In function `from_json`, use function [`at()`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a93403e803947b86f4da2d1fb3345cf2c.html#a93403e803947b86f4da2d1fb3345cf2c) to access the object values rather than `operator[]`. In case a key does not exist, `at` throws an exception that you can handle, whereas `operator[]` exhibits undefined behavior.
* In case your type contains several `operator=` definitions, code like `your_variable = your_json;` [may not compile](https://github.com/nlohmann/json/issues/667). You need to write `your_variable = your_json.get<decltype your_variable>();` instead.
* You do not need to add serializers or deserializers for STL types like `std::vector`: the library already implements these.
* Be careful with the definition order of the `from_json`/`to_json` functions: If a type `B` has a member of type `A`, you **MUST** define `to_json(A)` before `to_json(B)`. Look at [issue 561](https://github.com/nlohmann/json/issues/561) for more details.
#### How do I convert third-party types?
This requires a bit more advanced technique. But first, let's see how this conversion mechanism works:
The library uses **JSON Serializers** to convert types to json.
The default serializer for `nlohmann::json` is `nlohmann::adl_serializer` (ADL means [Argument-Dependent Lookup](http://en.cppreference.com/w/cpp/language/adl)).
It is implemented like this (simplified):
```cpp
template<typenameT>
structadl_serializer{
staticvoidto_json(json&j,constT&value){
// calls the "to_json" method in T's namespace
}
staticvoidfrom_json(constjson&j,T&value){
// same thing, but with the "from_json" method
}
};
```
This serializer works fine when you have control over the type's namespace. However, what about `boost::optional`, or `std::filesystem::path` (C++17)? Hijacking the `boost` namespace is pretty bad, and it's illegal to add something other than template specializations to `std`...
To solve this, you need to add a specialization of `adl_serializer` to the `nlohmann` namespace, here's an example:
```cpp
// partial specialization (full specialization works too)
#### How can I use `get()` for non-default constructible/non-copyable types?
There is a way, if your type is [MoveConstructible](http://en.cppreference.com/w/cpp/concept/MoveConstructible). You will need to specialize the `adl_serializer` as well, but with a special `from_json` overload:
```cpp
structmove_only_type{
move_only_type()=delete;
move_only_type(intii):i(ii){}
move_only_type(constmove_only_type&)=delete;
move_only_type(move_only_type&&)=default;
inti;
};
namespacenlohmann{
template<>
structadl_serializer<move_only_type>{
// note: the return type is no longer 'void', and the method only takes
// one argument
staticmove_only_typefrom_json(constjson&j){
return{j.get<int>()};
}
// Here's the catch! You must provide a to_json method! Otherwise you
// will not be able to convert move_only_type to json, since you fully
// specialized adl_serializer on that type
staticvoidto_json(json&j,move_only_typet){
j=t.i;
}
};
}
```
#### Can I write my own serializer? (Advanced use)
Yes. You might want to take a look at [`unit-udt.cpp`](https://github.com/nlohmann/json/blob/develop/test/src/unit-udt.cpp) in the test suite, to see a few examples.
If you write your own serializer, you'll need to do a few things:
* use a different `basic_json` alias than `nlohmann::json` (the last template parameter of `basic_json` is the `JSONSerializer`)
* use your `basic_json` alias (or a template parameter) in all your `to_json`/`from_json` methods
* use `nlohmann::to_json` and `nlohmann::from_json` when you need ADL
Here is an example, without simplifications, that only accepts types with a size <= 32, and uses ADL.
```cpp
// You should use void as a second template argument
Be **very** careful when reimplementing your serializer, you can stack overflow if you don't pay attention:
```cpp
template<typenameT,void>
structbad_serializer
{
template<typenameBasicJsonType>
staticvoidto_json(BasicJsonType&j,constT&value){
// this calls BasicJsonType::json_serializer<T>::to_json(j, value);
// if BasicJsonType::json_serializer == bad_serializer ... oops!
j=value;
}
template<typenameBasicJsonType>
staticvoidto_json(constBasicJsonType&j,T&value){
// this calls BasicJsonType::json_serializer<T>::from_json(j, value);
// if BasicJsonType::json_serializer == bad_serializer ... oops!
value=j.templateget<T>();// oops!
}
};
```
### Binary formats (CBOR and MessagePack)
Though JSON is a ubiquitous data format, it is not a very compact format suitable for data exchange, for instance over a network. Hence, the library supports [CBOR](http://cbor.io) (Concise Binary Object Representation) and [MessagePack](http://msgpack.org) to efficiently encode JSON values to byte vectors and to decode such vectors.
Though it's 2017 already, the support for C++11 is still a bit sparse. Currently, the following compilers are known to work:
- GCC 4.9 - 7.2 (and possibly later)
- Clang 3.4 - 5.0 (and possibly later)
- Intel C++ Compiler 17.0.2 (and possibly later)
- Microsoft Visual C++ 2015 / Build Tools 14.0.25123.0 (and possibly later)
- Microsoft Visual C++ 2017 / Build Tools 15.5.180.51428 (and possibly later)
I would be happy to learn about other compilers/versions.
Please note:
- GCC 4.8 does not work because of two bugs ([55817](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55817) and [57824](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57824)) in the C++11 support. Note there is a [pull request](https://github.com/nlohmann/json/pull/212) to fix some of the issues.
- Android defaults to using very old compilers and C++ libraries. To fix this, add the following to your `Application.mk`. This will switch to the LLVM C++ library, the Clang compiler, and enable C++11 and other features disabled by default.
```
APP_STL := c++_shared
NDK_TOOLCHAIN_VERSION := clang3.6
APP_CPPFLAGS += -frtti -fexceptions
```
The code compiles successfully with [Android NDK](https://developer.android.com/ndk/index.html?hl=ml), Revision 9 - 11 (and possibly later) and [CrystaX's Android NDK](https://www.crystax.net/en/android/ndk) version 10.
- For GCC running on MinGW or Android SDK, the error `'to_string' is not a member of 'std'` (or similarly, for `strtod`) may occur. Note this is not an issue with the code, but rather with the compiler itself. On Android, see above to build with a newer environment. For MinGW, please refer to [this site](http://tehsausage.com/mingw-to-string) and [this discussion](https://github.com/nlohmann/json/issues/136) for information on how to fix this bug. For Android NDK using `APP_STL := gnustl_static`, please refer to [this discussion](https://github.com/nlohmann/json/issues/219).
The following compilers are currently used in continuous integration at [Travis](https://travis-ci.org/nlohmann/json) and [AppVeyor](https://ci.appveyor.com/project/nlohmann/json):
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
If you have questions regarding the library, I would like to invite you to [open an issue at Github](https://github.com/nlohmann/json/issues/new). Please describe your request, problem, or question as detailed as possible, and also mention the version of the library you are using as well as the version of your compiler and operating system. Opening an issue at Github allows other users and contributors to this library to collaborate. For instance, I have little experience with MSVC, and most issues in this regard have been solved by a growing community. If you have a look at the [closed issues](https://github.com/nlohmann/json/issues?q=is%3Aissue+is%3Aclosed), you will see that we react quite timely in most cases.
Only if your request would contain confidential information, please [send me an email](mailto:mail@nlohmann.me). For encrypted messages, please use [this key](https://keybase.io/nlohmann/pgp_keys.asc).
## Thanks
I deeply appreciate the help of the following people.
- [Teemperor](https://github.com/Teemperor) implemented CMake support and lcov integration, realized escape and Unicode handling in the string parser, and fixed the JSON serialization.
- [elliotgoodrich](https://github.com/elliotgoodrich) fixed an issue with double deletion in the iterator classes.
- [kirkshoop](https://github.com/kirkshoop) made the iterators of the class composable to other libraries.
@@ -372,20 +832,153 @@ I deeply appreciate the help of the following people.
- [Eric Cornelius](https://github.com/EricMCornelius) pointed out a bug in the handling with NaN and infinity values. He also improved the performance of the string escaping.
- [易思龙](https://github.com/likebeta) implemented a conversion from anonymous enums.
- [kepkin](https://github.com/kepkin) patiently pushed forward the support for Microsoft Visual studio.
- [gregmarr](https://github.com/gregmarr) simplified the implementation of reverse iterators.
- [gregmarr](https://github.com/gregmarr) simplified the implementation of reverse iterators and helped with numerous hints and improvements. In particular, he pushed forward the implementation of user-defined types.
- [Caio Luppi](https://github.com/caiovlp) fixed a bug in the Unicode handling.
- [dariomt](https://github.com/dariomt) fixed some typos in the examples.
- [Daniel Frey](https://github.com/d-frey) cleaned up some pointers and implemented exception-safe memory allocation.
- [Colin Hirsch](https://github.com/ColinH) took care of a small namespace issue.
- [Huu Nguyen](https://github.com/whoshuu) correct a variable name in the documentation.
- [Silverweed](https://github.com/silverweed) overloaded `parse()` to accept an rvalue reference.
- [dariomt](https://github.com/dariomt) fixed a subtlety in MSVC type support and implemented the `get_ref()` function to get a reference to stored values.
- [ZahlGraf](https://github.com/ZahlGraf) added a workaround that allows compilation using Android NDK.
- [whackashoe](https://github.com/whackashoe) replaced a function that was marked as unsafe by Visual Studio.
- [406345](https://github.com/406345) fixed two small warnings.
- [Glen Fernandes](https://github.com/glenfe) noted a potential portability problem in the `has_mapped_type` function.
- [Corbin Hughes](https://github.com/nibroc) fixed some typos in the contribution guidelines.
- [twelsby](https://github.com/twelsby) fixed the array subscript operator, an issue that failed the MSVC build, and floating-point parsing/dumping. He further added support for unsigned integer numbers and implemented better roundtrip support for parsed numbers.
- [Volker Diels-Grabsch](https://github.com/vog) fixed a link in the README file.
- [msm-](https://github.com/msm-) added support for american fuzzy lop.
- [Annihil](https://github.com/Annihil) fixed an example in the README file.
- [Themercee](https://github.com/Themercee) noted a wrong URL in the README file.
- [Lv Zheng](https://github.com/lv-zheng) fixed a namespace issue with `int64_t` and `uint64_t`.
- [abc100m](https://github.com/abc100m) analyzed the issues with GCC 4.8 and proposed a [partial solution](https://github.com/nlohmann/json/pull/212).
- [zewt](https://github.com/zewt) added useful notes to the README file about Android.
- [Róbert Márki](https://github.com/robertmrk) added a fix to use move iterators and improved the integration via CMake.
- [Chris Kitching](https://github.com/ChrisKitching) cleaned up the CMake files.
- [Tom Needham](https://github.com/06needhamt) fixed a subtle bug with MSVC 2015 which was also proposed by [Michael K.](https://github.com/Epidal).
- [Mário Feroldi](https://github.com/thelostt) fixed a small typo.
- [duncanwerner](https://github.com/duncanwerner) found a really embarrassing performance regression in the 2.0.0 release.
- [Damien](https://github.com/dtoma) fixed one of the last conversion warnings.
- [Thomas Braun](https://github.com/t-b) fixed a warning in a test case.
- [Théo DELRIEU](https://github.com/theodelrieu) patiently and constructively oversaw the long way toward [iterator-range parsing](https://github.com/nlohmann/json/issues/290). He also implemented the magic behind the serialization/deserialization of user-defined types.
- [Stefan](https://github.com/5tefan) fixed a minor issue in the documentation.
- [Vasil Dimov](https://github.com/vasild) fixed the documentation regarding conversions from `std::multiset`.
- [ChristophJud](https://github.com/ChristophJud) overworked the CMake files to ease project inclusion.
- [Vladimir Petrigo](https://github.com/vpetrigo) made a SFINAE hack more readable and added Visual Studio 17 to the build matrix.
- [Denis Andrejew](https://github.com/seeekr) fixed a grammar issue in the README file.
- [Pierre-Antoine Lacaze](https://github.com/palacaze) found a subtle bug in the `dump()` function.
- [TurpentineDistillery](https://github.com/TurpentineDistillery) pointed to [`std::locale::classic()`](http://en.cppreference.com/w/cpp/locale/locale/classic) to avoid too much locale joggling, found some nice performance improvements in the parser, improved the benchmarking code, and realized locale-independent number parsing and printing.
- [cgzones](https://github.com/cgzones) had an idea how to fix the Coverity scan.
- [Jared Grubb](https://github.com/jaredgrubb) silenced a nasty documentation warning.
- [Yixin Zhang](https://github.com/qwename) fixed an integer overflow check.
- [Bosswestfalen](https://github.com/Bosswestfalen) merged two iterator classes into a smaller one.
- [Daniel599](https://github.com/Daniel599) helped to get Travis execute the tests with Clang's sanitizers.
- [Jonathan Lee](https://github.com/vjon) fixed an example in the README file.
- [gnzlbg](https://github.com/gnzlbg) supported the implementation of user-defined types.
- [Alexej Harm](https://github.com/qis) helped to get the user-defined types working with Visual Studio.
- [Jared Grubb](https://github.com/jaredgrubb) supported the implementation of user-defined types.
- [EnricoBilla](https://github.com/EnricoBilla) noted a typo in an example.
- [Martin Hořeňovský](https://github.com/horenmar) found a way for a 2x speedup for the compilation time of the test suite.
- [ukhegg](https://github.com/ukhegg) found proposed an improvement for the examples section.
- [rswanson-ihi](https://github.com/rswanson-ihi) noted a typo in the README.
- [Mihai Stan](https://github.com/stanmihai4) fixed a bug in the comparison with `nullptr`s.
- [Tushar Maheshwari](https://github.com/tusharpm) added [cotire](https://github.com/sakra/cotire) support to speed up the compilation.
- [TedLyngmo](https://github.com/TedLyngmo) noted a typo in the README, removed unnecessary bit arithmetic, and fixed some `-Weffc++` warnings.
- [Krzysztof Woś](https://github.com/krzysztofwos) made exceptions more visible.
- [ftillier](https://github.com/ftillier) fixed a compiler warning.
- [tinloaf](https://github.com/tinloaf) made sure all pushed warnings are properly popped.
- [Fytch](https://github.com/Fytch) found a bug in the documentation.
- [Jay Sistar](https://github.com/Type1J) implemented a Meson build description.
- [Henry Lee](https://github.com/HenryRLee) fixed a warning in ICC and improved the iterator implementation.
- [Vincent Thiery](https://github.com/vthiery) maintains a package for the Conan package manager.
- [Steffen](https://github.com/koemeet) fixed a potential issue with MSVC and `std::min`.
- [Mike Tzou](https://github.com/Chocobo1) fixed some typos.
- [amrcode](https://github.com/amrcode) noted a missleading documentation about comparison of floats.
- [Oleg Endo](https://github.com/olegendo) reduced the memory consumption by replacing `<iostream>` with `<iosfwd>`.
- [dan-42](https://github.com/dan-42) cleaned up the CMake files to simplify including/reusing of the library.
- [Nikita Ofitserov](https://github.com/himikof) allowed for moving values from initializer lists.
- [Greg Hurrell](https://github.com/wincent) fixed a typo.
- [Dmitry Kukovinets](https://github.com/DmitryKuk) fixed a typo.
- [kbthomp1](https://github.com/kbthomp1) fixed an issue related to the Intel OSX compiler.
- [Markus Werle](https://github.com/daixtrose) fixed a typo.
- [WebProdPP](https://github.com/WebProdPP) fixed a subtle error in a precondition check.
- [Alex](https://github.com/leha-bot) noted an error in a code sample.
- [Tom de Geus](https://github.com/tdegeus) reported some warnings with ICC and helped fixing them.
- [Perry Kundert](https://github.com/pjkundert) simplified reading from input streams.
- [Sonu Lohani](https://github.com/sonulohani) fixed a small compilation error.
- [Jamie Seward](https://github.com/jseward) fixed all MSVC warnings.
- [Nate Vargas](https://github.com/eld00d) added a Doxygen tag file.
- [pvleuven](https://github.com/pvleuven) helped fixing a warning in ICC.
- [Pavel](https://github.com/crea7or) helped fixing some warnings in MSVC.
- [Jamie Seward](https://github.com/jseward) avoided unneccessary string copies in `find()` and `count()`.
- [Mitja](https://github.com/Itja) fixed some typos.
- [Jorrit Wronski](https://github.com/jowr) updated the Hunter package links.
- [Matthias Möller](https://github.com/TinyTinni) added a `.natvis` for the MSVC debug view.
- [bogemic](https://github.com/bogemic) fixed some C++17 deprecation warnings.
- [Eren Okka](https://github.com/erengy) fixed some MSVC warnings.
Thanks a lot for helping out! Please [let me know](mailto:mail@nlohmann.me) if I forgot someone.
## Used third-party tools
The library itself contains of a single header file licensed under the MIT license. However, it is built, tested, documented, and whatnot using a lot of third-party tools and services. Thanks a lot!
- [**American fuzzy lop**](http://lcamtuf.coredump.cx/afl/) for fuzz testing
- [**AppVeyor**](https://www.appveyor.com) for [continuous integration](https://ci.appveyor.com/project/nlohmann/json) on Windows
- [**Artistic Style**](http://astyle.sourceforge.net) for automatic source code identation
- [**benchpress**](https://github.com/sbs-ableton/benchpress) to benchmark the code
- [**Catch**](https://github.com/philsquared/Catch) for the unit tests
- [**Clang**](http://clang.llvm.org) for compilation with code sanitizers
- [**Cmake**](https://cmake.org) for build automation
- [**Codacity**](https://www.codacy.com) for further [code analysis](https://www.codacy.com/app/nlohmann/json)
- [**Coveralls**](https://coveralls.io) to measure [code coverage](https://coveralls.io/github/nlohmann/json)
- [**Coverity Scan**](https://scan.coverity.com) for [static analysis](https://scan.coverity.com/projects/nlohmann-json)
- [**cppcheck**](http://cppcheck.sourceforge.net) for static analysis
- [**cxxopts**](https://github.com/jarro2783/cxxopts) to let benchpress parse command-line parameters
- [**Doxygen**](http://www.stack.nl/~dimitri/doxygen/) to generate [documentation](https://nlohmann.github.io/json/)
- [**git-update-ghpages**](https://github.com/rstacruz/git-update-ghpages) to upload the documentation to gh-pages
- [**Github Changelog Generator**](https://github.com/skywinder/github-changelog-generator) to generate the [ChangeLog](https://github.com/nlohmann/json/blob/develop/ChangeLog.md)
- [**libFuzzer**](http://llvm.org/docs/LibFuzzer.html) to implement fuzz testing for OSS-Fuzz
- [**OSS-Fuzz**](https://github.com/google/oss-fuzz) for continuous fuzz testing of the library
- [**Probot**](https://probot.github.io) for automating maintainer tasks such as closing stale issues, requesting missing information, or detecting toxic comments.
- [**send_to_wandbox**](https://github.com/nlohmann/json/blob/develop/doc/scripts/send_to_wandbox.py) to send code examples to [Wandbox](http://melpon.org/wandbox)
- [**Travis**](https://travis-ci.org) for [continuous integration](https://travis-ci.org/nlohmann/json) on Linux and macOS
- [**Valgrind**](http://valgrind.org) to check for correct memory management
- [**Wandbox**](http://melpon.org/wandbox) for [online examples](https://wandbox.org/permlink/Op57X0V7fTf2tdwl)
## Projects using JSON for Modern C++
The library is currently used in Apple macOS Sierra and iOS 10. I am not sure what they are using the library for, but I am happy that it runs on so many devices.
## Notes
- The code contains numerous debug **assertions** which can be switched off by defining the preprocessor macro `NDEBUG`, see the [documentation of `assert`](http://en.cppreference.com/w/cpp/error/assert). In particular, note [`operator[]`](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a2e26bd0b0168abb61f67ad5bcd5b9fa1.html#a2e26bd0b0168abb61f67ad5bcd5b9fa1) implements **unchecked access** for const objects: If the given key is not present, the behavior is undefined (think of a dereferenced null pointer) and yields an [assertion failure](https://github.com/nlohmann/json/issues/289) if assertions are switched on. If you are not sure whether an element in an object exists, use checked access with the [`at()` function](https://nlohmann.github.io/json/classnlohmann_1_1basic__json_a674de1ee73e6bf4843fc5dc1351fb726.html#a674de1ee73e6bf4843fc5dc1351fb726).
- As the exact type of a number is not defined in the [JSON specification](http://rfc7159.net/rfc7159), this library tries to choose the best fitting C++ number type automatically. As a result, the type `double` may be used to store numbers which may yield [**floating-point exceptions**](https://github.com/nlohmann/json/issues/181) in certain rare situations if floating-point exceptions have been unmasked in the calling code. These exceptions are not caused by the library and need to be fixed in the calling code, such as by re-masking the exceptions prior to calling library functions.
- The library supports **Unicode input** as follows:
- Only **UTF-8** encoded input is supported which is the default encoding for JSON according to [RFC 7159](http://rfc7159.net/rfc7159#rfc.section.8.1).
- Other encodings such as Latin-1, UTF-16, or UTF-32 are not supported and will yield parse or serialization errors.
- [Unicode noncharacters](http://www.unicode.org/faq/private_use.html#nonchar1) will not be replaced by the library.
- Invalid surrogates (e.g., incomplete pairs such as `\uDEAD`) will yield parse errors.
- The strings stored in the library are UTF-8 encoded. When using the default string type (`std::string`), note that its length/size functions return the number of stored bytes rather than the number of characters or glyphs.
- The code can be compiled without C++ **runtime type identification** features; that is, you can use the `-fno-rtti` compiler flag.
- **Exceptions** are used widely within the library. They can, however, be switched off with either using the compiler flag `-fno-exceptions` or by defining the symbol `JSON_NOEXCEPTION`. In this case, exceptions are replaced by an `abort()` call.
- By default, the library does not preserve the **insertion order of object elements**. This is standards-compliant, as the [JSON standard](https://tools.ietf.org/html/rfc7159.html) defines objects as "an unordered collection of zero or more name/value pairs". If you do want to preserve the insertion order, you can specialize the object type with containers like [`tsl::ordered_map`](https://github.com/Tessil/ordered-map) ([integration](https://github.com/nlohmann/json/issues/546#issuecomment-304447518)) or [`nlohmann::fifo_map`](https://github.com/nlohmann/fifo_map) ([integration](https://github.com/nlohmann/json/issues/485#issuecomment-333652309)).
The 1.0.0 release should be the first "official" release after the initial announcement of the class in January 2015 via reddit ("0.1.0") and a heavily overworked second version ("0.2.0") in February.
### Changes
- *Changed:* In the generic class `basic_json`, all JSON value types (array, object, string, bool, integer number, and floating-point) are now **templated**. That is, you can choose whether you like a `std::list` for your arrays or an `std::unordered_map` for your objects. The specialization `json` sets some reasonable defaults.
- *Changed:* The library now consists of a **single header**, called `json.hpp`. Consequently, build systems such as Automake or CMake are not any longer required.
- *Changed:* The **deserialization** is now supported by a lexer generated with [re2c](http://re2c.org) from file [`src/json.hpp.re2c`](https://github.com/nlohmann/json/blob/master/src/json.hpp.re2c). As a result, we strictly follow the JSON specification. Note neither the tool re2c nor its input are required to use the class.
- *Added:* The library now satisfies the [**ReversibleContainer**](http://en.cppreference.com/w/cpp/concept/ReversibleContainer) requirement. It hence provides four different iterators (`iterator`, `const_iterator`, `reverse_iterator`, and `const_reverse_iterator`), comparison functions, `swap()`, `size()`, `max_size()`, and `empty()` member functions.
- *Added*: The class uses **user-defined allocators** which default to `std::allocator`, but can be templated via parameter `Allocator`.
- *Added:* To simplify pretty-printing, the `std::setw`**stream manipulator** has been overloaded to set the desired indentation. Pretty-printing a JSON object `j` is as simple as `std::cout << std::setw(4) << j << '\n'`.
- *Changed*: The type `json::value_t::number` is now called `json::value_t::number_integer` to be more symmetric compared to `json::value_t::number_float`.
-*Added*: The documentation is generated with Doxygen and hosted at [nlohmann.github.io/json](http://nlohmann.github.io/json/). Every public member function is thoroughly described including an example which also can be [tried online](http://melpon.org/wandbox/permlink/GnGKwji06WeVonlI).
- *Added*: The class is heavily unit-tested (3341774 assertions) and has a [line coverage of 100%](https://coveralls.io/github/nlohmann/json). With every commit, the code is compiled with g++ 4.9, g++ 5.0, Clang 3.6 (thanks to [Travis CI](https://travis-ci.org/nlohmann/json)), and Microsoft Visual Studio 14 2015 (thanks to [AppVeyor](https://ci.appveyor.com/project/nlohmann/json)).
ALIASES+= liveexample{2}="@par Example\n \1 \n @includelineno \2.cpp \n Output (play with this example @htmlinclude \2.link):\n @verbinclude \2.output \n The example code above can be translated with @verbatim g++ -std=c++11 -Isrc doc/examples/\2.cpp -o \2 @endverbatim"
ALIASES+= requirement="@par Requirements\n"
ALIASES = "complexity=@par Complexity\n" \
"liveexample{2}=@par Example\n \1 \n @includelineno \2.cpp \n Output (play with this example @htmlinclude \2.link):\n @verbinclude \2.output \n The <a href= https://github.com/nlohmann/json/blob/develop/doc/examples/\2.cpp>example code</a> above can be translated with @verbatim g++ -std=c++11 -Isrc doc/examples/\2.cpp -o \2 @endverbatim" \
Some files were not shown because too many files have changed in this diff
Show More
Reference in New Issue
Block a user
Blocking a user prevents them from interacting with repositories, such as opening or commenting on pull requests or issues. Learn more about blocking a user.