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◆ parse() [2/2]
template<class IteratorType , typename std::enable_if< std::is_base_of< std::random_access_iterator_tag, typename std::iterator_traits< IteratorType >::iterator_category >::value, int >::type = 0>
static basic_json nlohmann::basic_json::parse |
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IteratorType |
first, |
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IteratorType |
last, |
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const parser_callback_t |
cb = nullptr , |
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const bool |
allow_exceptions = true |
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) |
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inlinestatic |
This function reads from an iterator range of a container with contiguous storage of 1-byte values. Compatible container types include std::vector , std::string , std::array , std::valarray , and std::initializer_list . Furthermore, C-style arrays can be used with std::begin() /std::end() . User-defined containers can be used as long as they implement random-access iterators and a contiguous storage.
- Precondition
- The iterator range is contiguous. Violating this precondition yields undefined behavior. This precondition is enforced with an assertion.
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Each element in the range has a size of 1 byte. Violating this precondition yields undefined behavior. This precondition is enforced with a static assertion.
- Warning
- There is no way to enforce all preconditions at compile-time. If the function is called with noncompliant iterators and with assertions switched off, the behavior is undefined and will most likely yield segmentation violation.
- Template Parameters
-
IteratorType | iterator of container with contiguous storage |
- Parameters
-
[in] | first | begin of the range to parse (included) |
[in] | last | end of the range to parse (excluded) |
[in] | cb | a parser callback function of type parser_callback_t which is used to control the deserialization by filtering unwanted values (optional) |
[in] | allow_exceptions | whether to throw exceptions in case of a parse error (optional, true by default) |
- Returns
- deserialized JSON value; in case of a parse error and allow_exceptions set to
false , the return value will be value_t::discarded.
- Exceptions
-
parse_error.101 | in case of an unexpected token |
parse_error.102 | if to_unicode fails or surrogate error |
parse_error.103 | if to_unicode fails |
- Complexity
- Linear in the length of the input. The parser is a predictive LL(1) parser. The complexity can be higher if the parser callback function cb has a super-linear complexity.
- Note
- A UTF-8 byte order mark is silently ignored.
- Example
- The example below demonstrates the
parse() function reading from an iterator range.
3 #include <nlohmann/json.hpp>
10 std::vector<uint8_t> text = { '[', '1', ',', '2', ',', '3', ']', '\0'};
14 std::cout << std::setw(4) << j_complete << "\n\n";
Output (play with this example online): [
1,
2,
3
]
The example code above can be translated withg++ -std=c++11 -Isingle_include doc/examples/parse__iteratortype__parser_callback_t.cpp -o parse__iteratortype__parser_callback_t
- Since
- version 2.0.3
Definition at line 20887 of file json.hpp.
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