|
◆ parse() [2/2]
template<template< typename U, typename V, typename... Args > class ObjectType = std::map, template< typename U, typename... Args > class ArrayType = std::vector, class StringType = std::string, class BooleanType = bool, class NumberIntegerType = std::int64_t, class NumberUnsignedType = std::uint64_t, class NumberFloatType = double, template< typename U > class AllocatorType = std::allocator, template< typename T, typename SFINAE=void > class JSONSerializer = adl_serializer>
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>
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.
-
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
- result of the deserialization
- 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"; basic_json<> json default JSON class
static basic_json parse(detail::input_adapter &&i, const parser_callback_t cb=nullptr, const bool allow_exceptions=true) deserialize from a compatible input
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 18583 of file json.hpp.
|