Complete documentation for 3.11.0 (#3464)

* 👥 update contributor and sponsor list

* 🚧 document BJData format

* 🚧 document BJData format

* 📝 clarified documentation of [json.exception.parse_error.112]

* ✏️ adjust titles

* 📝 add more examples

* 🚨 adjust warnings for index.md files

* 📝 add more examples

* 🔥 remove example for deprecated code

* 📝 add missing enum entry

* 📝 overwork table for binary formats

* ✅ add test to create table for binary formats

* 📝 fix wording in example

* 📝 add more examples

* Update iterators.md (#3481)

* ✨ add check for overloads to linter #3455

* 👥 update contributor list

* 📝 add more examples

* 📝 fix documentation

* 📝 add more examples

* 🎨 fix indentation

* 🔥 remove example for destructor

* 📝 overwork documentation

* Updated BJData documentation, #3464 (#3493)

* update bjdata.md for #3464

* Minor edit

* Fix URL typo

* Add info on demoting ND array to a 1-D optimized array when singleton dimension

Co-authored-by: Chaoqi Zhang <prncoprs@163.com>
Co-authored-by: Qianqian Fang <fangqq@gmail.com>

README.md

@@ -54,7 +54,7 @@ There are myriads of [JSON](https://json.org) libraries out there, and each may
 
 - **Trivial integration**. Our whole code consists of a single header file [`json.hpp`](https://github.com/nlohmann/json/blob/develop/single_include/nlohmann/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/tree/develop/tests/src) and covers [100%](https://coveralls.io/r/nlohmann/json) of the code, including all exceptional behavior. Furthermore, we checked with [Valgrind](https://valgrind.org) and the [Clang Sanitizers](https://clang.llvm.org/docs/index.html) that there are no memory leaks. [Google OSS-Fuzz](https://github.com/google/oss-fuzz/tree/master/projects/json) additionally runs fuzz tests against all parsers 24/7, effectively executing billions of tests so far. To maintain high quality, the project is following the [Core Infrastructure Initiative (CII) best practices](https://bestpractices.coreinfrastructure.org/projects/289).
+- **Serious testing**. Our code is heavily [unit-tested](https://github.com/nlohmann/json/tree/develop/tests/src) and covers [100%](https://coveralls.io/r/nlohmann/json) of the code, including all exceptional behavior. Furthermore, we checked with [Valgrind](https://valgrind.org) and the [Clang Sanitizers](https://clang.llvm.org/docs/index.html) that there are no memory leaks. [Google OSS-Fuzz](https://github.com/google/oss-fuzz/tree/master/projects/json) additionally runs fuzz tests against all parsers 24/7, effectively executing billions of tests so far. 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:
 
@@ -69,6 +69,10 @@ See the [contribution guidelines](https://github.com/nlohmann/json/blob/master/.
 
 You can sponsor this library at [GitHub Sponsors](https://github.com/sponsors/nlohmann).
 
+### :office: Corporate Sponsor
+
+[![](https://upload.wikimedia.org/wikipedia/commons/thumb/9/9e/Codacy-logo-black.svg/320px-Codacy-logo-black.svg.png)](https://github.com/codacy)
+
 ### :label: Named Sponsors
 
 - [Michael Hartmann](https://github.com/reFX-Mike)
@@ -1599,6 +1603,20 @@ I deeply appreciate the help of the following people.
 - [Dirk Stolle](https://github.com/striezel) fixed typos in documentation.
 - [Daniel Albuschat](https://github.com/daniel-kun) corrected the parameter name in the `parse` documentation.
 - [Prince Mendiratta](https://github.com/Prince-Mendiratta) fixed a link to the FAQ.
+- [Florian Albrechtskirchinger](https://github.com/falbrechtskirchinger) implemented `std::string_view` support for object keys and made dozens of other improvements.
+- [Qianqian Fang](https://github.com/fangq) implemented the Binary JData (BJData) format.
+- [pketelsen](https://github.com/pketelsen) added macros `NLOHMANN_DEFINE_TYPE_INTRUSIVE_WITH_DEFAULT` and `NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE_WITH_DEFAULT`.
+- [DarkZeros](https://github.com/DarkZeros) adjusted to code to not clash with Arduino defines.
+- [flagarde](https://github.com/flagarde) fixed the output of `meta()` for MSVC.
+- [Giovanni Cerretani](https://github.com/gcerretani) fixed a check for `std::filesystem`.
+- [Dimitris Apostolou](https://github.com/rex4539) fixed a typo.
+- [Ferry Huberts](https://github.com/fhuberts) fixed a typo.
+- [Michael Nosthoff](https://github.com/heinemml) fixed a typo.
+- [JungHoon Lee](https://github.com/jhnlee) fixed a typo.
+- [Faruk D.](https://github.com/fdiblen) fixed the CITATION.CFF file.
+- [Andrea Cocito](https://github.com/puffetto) added a clarification on macro usage to the documentation.
+- [Krzysiek Karbowiak](https://github.com/kkarbowiak) refactored the tests to use `CHECK_THROWS_WITH_AS`.
+- [Chaoqi Zhang](https://github.com/prncoprs) fixed a typo.
 
 Thanks a lot for helping out! Please [let me know](mailto:mail@nlohmann.me) if I forgot someone.
 
@@ -1613,7 +1631,7 @@ The library itself consists of a single header file licensed under the MIT licen
 - [**Artistic Style**](http://astyle.sourceforge.net) for automatic source code indentation
 - [**Clang**](https://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)
+- [**Codacy**](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

docs/examples/byte_container_with_subtype__byte_container_with_subtype.cpp

@@ -0,0 +1,23 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+// define a byte container based on std::vector
+using byte_container_with_subtype = nlohmann::byte_container_with_subtype<std::vector<std::uint8_t>>;
+
+using json = nlohmann::json;
+
+int main()
+{
+    // (1) create empty container
+    auto c1 = byte_container_with_subtype();
+
+    std::vector<std::uint8_t> bytes = {{0xca, 0xfe, 0xba, 0xbe}};
+
+    // (2) create container
+    auto c2 = byte_container_with_subtype(bytes);
+
+    // (3) create container with subtype
+    auto c3 = byte_container_with_subtype(bytes, 42);
+
+    std::cout << json(c1) << "\n" << json(c2) << "\n" << json(c3) << std::endl;
+}

docs/examples/byte_container_with_subtype__byte_container_with_subtype.output

@@ -0,0 +1,3 @@
+{"bytes":[],"subtype":null}
+{"bytes":[202,254,186,190],"subtype":null}
+{"bytes":[202,254,186,190],"subtype":42}

docs/examples/byte_container_with_subtype__clear_subtype.cpp

@@ -0,0 +1,21 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+// define a byte container based on std::vector
+using byte_container_with_subtype = nlohmann::byte_container_with_subtype<std::vector<std::uint8_t>>;
+
+using json = nlohmann::json;
+
+int main()
+{
+    std::vector<std::uint8_t> bytes = {{0xca, 0xfe, 0xba, 0xbe}};
+
+    // create container with subtype
+    auto c1 = byte_container_with_subtype(bytes, 42);
+
+    std::cout << "before calling clear_subtype(): " << json(c1) << '\n';
+
+    c1.clear_subtype();
+
+    std::cout << "after calling clear_subtype(): " << json(c1) << '\n';
+}

docs/examples/byte_container_with_subtype__clear_subtype.output

@@ -0,0 +1,2 @@
+before calling clear_subtype(): {"bytes":[202,254,186,190],"subtype":42}
+after calling clear_subtype(): {"bytes":[202,254,186,190],"subtype":null}

docs/examples/byte_container_with_subtype__has_subtype.cpp

@@ -0,0 +1,19 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+// define a byte container based on std::vector
+using byte_container_with_subtype = nlohmann::byte_container_with_subtype<std::vector<std::uint8_t>>;
+
+int main()
+{
+    std::vector<std::uint8_t> bytes = {{0xca, 0xfe, 0xba, 0xbe}};
+
+    // create container
+    auto c1 = byte_container_with_subtype(bytes);
+
+    // create container with subtype
+    auto c2 = byte_container_with_subtype(bytes, 42);
+
+    std::cout << std::boolalpha << "c1.has_subtype() = " << c1.has_subtype()
+              << "\nc2.has_subtype() = " << c2.has_subtype() << std::endl;
+}

docs/examples/byte_container_with_subtype__has_subtype.output

@@ -0,0 +1,2 @@
+c1.has_subtype() = false
+c2.has_subtype() = true

docs/examples/byte_container_with_subtype__set_subtype.cpp

@@ -0,0 +1,22 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+// define a byte container based on std::vector
+using byte_container_with_subtype = nlohmann::byte_container_with_subtype<std::vector<std::uint8_t>>;
+
+using json = nlohmann::json;
+
+int main()
+{
+    std::vector<std::uint8_t> bytes = {{0xca, 0xfe, 0xba, 0xbe}};
+
+    // create container without subtype
+    auto c = byte_container_with_subtype(bytes);
+
+    std::cout << "before calling set_subtype(42): " << json(c) << '\n';
+
+    // set the subtype
+    c.set_subtype(42);
+
+    std::cout << "after calling set_subtype(42): " << json(c) << '\n';
+}

docs/examples/byte_container_with_subtype__set_subtype.output

@@ -0,0 +1,2 @@
+before calling set_subtype(42): {"bytes":[202,254,186,190],"subtype":null}
+after calling set_subtype(42): {"bytes":[202,254,186,190],"subtype":42}

docs/examples/byte_container_with_subtype__subtype.cpp

@@ -0,0 +1,22 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+// define a byte container based on std::vector
+using byte_container_with_subtype = nlohmann::byte_container_with_subtype<std::vector<std::uint8_t>>;
+
+int main()
+{
+    std::vector<std::uint8_t> bytes = {{0xca, 0xfe, 0xba, 0xbe}};
+
+    // create container
+    auto c1 = byte_container_with_subtype(bytes);
+
+    // create container with subtype
+    auto c2 = byte_container_with_subtype(bytes, 42);
+
+    std::cout << "c1.subtype() = " << c1.subtype()
+              << "\nc2.subtype() = " << c2.subtype() << std::endl;
+
+    // in case no subtype is set, return special value
+    assert(c1.subtype() == static_cast<byte_container_with_subtype::subtype_type>(-1));
+}

docs/examples/byte_container_with_subtype__subtype.output

@@ -0,0 +1,2 @@
+c1.subtype() = 18446744073709551615
+c2.subtype() = 42

docs/examples/cbor_tag_handler_t.cpp

@@ -0,0 +1,28 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+using json = nlohmann::json;
+
+int main()
+{
+    // tagged byte string
+    std::vector<std::uint8_t> vec = {{0xd8, 0x42, 0x44, 0xcA, 0xfe, 0xba, 0xbe}};
+
+    // cbor_tag_handler_t::error throws
+    try
+    {
+        auto b_throw_on_tag = json::from_cbor(vec, true, true, json::cbor_tag_handler_t::error);
+    }
+    catch (json::parse_error& e)
+    {
+        std::cout << e.what() << std::endl;
+    }
+
+    // cbor_tag_handler_t::ignore ignores the tag
+    auto b_ignore_tag = json::from_cbor(vec, true, true, json::cbor_tag_handler_t::ignore);
+    std::cout << b_ignore_tag << std::endl;
+
+    // cbor_tag_handler_t::store stores the tag as binary subtype
+    auto b_store_tag = json::from_cbor(vec, true, true, json::cbor_tag_handler_t::store);
+    std::cout << b_store_tag << std::endl;
+}

docs/examples/cbor_tag_handler_t.output

@@ -0,0 +1,3 @@
+[json.exception.parse_error.112] parse error at byte 1: syntax error while parsing CBOR value: invalid byte: 0xD8
+{"bytes":[202,254,186,190],"subtype":null}
+{"bytes":[202,254,186,190],"subtype":66}

docs/examples/default_object_comparator_t.cpp

@@ -0,0 +1,11 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+using json = nlohmann::json;
+
+int main()
+{
+    std::cout << std::boolalpha
+              << "one < two : " << json::default_object_comparator_t{}("one", "two") << "\n"
+              << "three < four : " << json::default_object_comparator_t{}("three", "four") << std::endl;
+}

docs/examples/default_object_comparator_t.output

@@ -0,0 +1,2 @@
+one < two : true
+three < four : false

docs/examples/error_handler_t.cpp

@@ -0,0 +1,24 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+using json = nlohmann::json;
+
+int main()
+{
+    // create JSON value with invalid UTF-8 byte sequence
+    json j_invalid = "ä\xA9ü";
+    try
+    {
+        std::cout << j_invalid.dump() << std::endl;
+    }
+    catch (json::type_error& e)
+    {
+        std::cout << e.what() << std::endl;
+    }
+
+    std::cout << "string with replaced invalid characters: "
+              << j_invalid.dump(-1, ' ', false, json::error_handler_t::replace)
+              << "\nstring with ignored invalid characters: "
+              << j_invalid.dump(-1, ' ', false, json::error_handler_t::ignore)
+              << '\n';
+}

docs/examples/error_handler_t.output

@@ -0,0 +1,3 @@
+[json.exception.type_error.316] invalid UTF-8 byte at index 2: 0xA9
+string with replaced invalid characters: "ä�ü"
+string with ignored invalid characters: "äü"

docs/examples/from_bjdata.cpp

@@ -0,0 +1,20 @@
+#include <iostream>
+#include <iomanip>
+#include <nlohmann/json.hpp>
+
+using json = nlohmann::json;
+
+int main()
+{
+    // create byte vector
+    std::vector<std::uint8_t> v = {0x7B, 0x69, 0x07, 0x63, 0x6F, 0x6D, 0x70, 0x61,
+                                   0x63, 0x74, 0x54, 0x69, 0x06, 0x73, 0x63, 0x68,
+                                   0x65, 0x6D, 0x61, 0x69, 0x00, 0x7D
+                                  };
+
+    // deserialize it with BJData
+    json j = json::from_bjdata(v);
+
+    // print the deserialized JSON value
+    std::cout << std::setw(2) << j << std::endl;
+}

docs/examples/from_bjdata.output

@@ -0,0 +1,4 @@
+{
+  "compact": true,
+  "schema": 0
+}

docs/examples/get_allocator.cpp

@@ -0,0 +1,18 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+using json = nlohmann::json;
+
+int main()
+{
+    auto alloc = json::get_allocator();
+    using traits_t = std::allocator_traits<decltype(alloc)>;
+
+    json* j = traits_t::allocate(alloc, 1);
+    traits_t::construct(alloc, j, "Hello, world!");
+
+    std::cout << *j << std::endl;
+
+    traits_t::destroy(alloc, j);
+    traits_t::deallocate(alloc, j, 1);
+}

docs/examples/get_allocator.output

@@ -0,0 +1 @@
+"Hello, world!"

docs/examples/json_pointer__operator_string.cpp

@@ -0,0 +1,19 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+using json = nlohmann::json;
+
+int main()
+{
+    // different JSON Pointers
+    json::json_pointer ptr1("/foo/0");
+    json::json_pointer ptr2("/a~1b");
+
+    // implicit conversion to string
+    std::string s;
+    s += ptr1;
+    s += "\n";
+    s += ptr2;
+
+    std::cout << s << std::endl;
+}

docs/examples/json_pointer__operator_string.output

@@ -0,0 +1,2 @@
+/foo/0
+/a~1b

docs/examples/json_pointer__string_t.cpp

@@ -0,0 +1,13 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+using json = nlohmann::json;
+
+int main()
+{
+    json::json_pointer::string_t s = "This is a string.";
+
+    std::cout << s << std::endl;
+
+    std::cout << std::boolalpha << std::is_same<json::json_pointer::string_t, json::string_t>::value << std::endl;
+}

docs/examples/json_pointer__string_t.output

@@ -0,0 +1,2 @@
+This is a string.
+true

docs/examples/json_pointer__to_string.cpp

@@ -19,7 +19,6 @@ int main()
     json::json_pointer ptr11("/ ");
     json::json_pointer ptr12("/m~0n");
 
-
     std::cout << ptr1.to_string() << '\n'
               << ptr2.to_string() << '\n'
               << ptr3.to_string() << '\n'