basic_json::from_bson

// (1)
template<typename InputType>
static basic_json from_bson(InputType&& i,
                            const bool strict = true,
                            const bool allow_exceptions = true);
// (2)
template<typename IteratorType>
static basic_json from_bson(IteratorType first, IteratorType last,
                            const bool strict = true,
                            const bool allow_exceptions = true);

Deserializes a given input to a JSON value using the BSON (Binary JSON) serialization format.

Reads from a compatible input.
Reads from an iterator range.

The library maps BSON record types to JSON value types as follows:

BSON type	BSON marker byte	JSON value type
double	0x01	number_float
string	0x02	string
document	0x03	object
array	0x04	array
binary	0x05	binary
undefined	0x06	still unsupported
ObjectId	0x07	still unsupported
boolean	0x08	boolean
UTC Date-Time	0x09	still unsupported
null	0x0A	null
Regular Expr.	0x0B	still unsupported
DB Pointer	0x0C	still unsupported
JavaScript Code	0x0D	still unsupported
Symbol	0x0E	still unsupported
JavaScript Code	0x0F	still unsupported
int32	0x10	number_integer
Timestamp	0x11	still unsupported
128-bit decimal float	0x13	still unsupported
Max Key	0x7F	still unsupported
Min Key	0xFF	still unsupported

!!! warning

The mapping is **incomplete**. The unsupported mappings are indicated in the table above.

Template parameters

InputType

A compatible input, for instance:

an std::istream object
a FILE pointer
a C-style array of characters
a pointer to a null-terminated string of single byte characters
an object obj for which begin(obj) and end(obj) produces a valid pair of iterators.

IteratorType

a compatible iterator type

Parameters

i (in): an input in BSON format convertible to an input adapter
first (in): iterator to start of the input
last (in): iterator to end of the input
strict (in): whether to expect the input to be consumed until EOF (#!cpp true by default)
allow_exceptions (in): whether to throw exceptions in case of a parse error (optional, #!cpp true by default)

Return value

deserialized JSON value; in case of a parse error and allow_exceptions set to #!cpp false, the return value will be value_t::discarded. The latter can be checked with is_discarded.

Exceptions

Throws parse_error.114 if an unsupported BSON record type is encountered.

Exception safety

Strong guarantee: if an exception is thrown, there are no changes in the JSON value.

Complexity

Linear in the size of the input.

Example

??? example

The example shows the deserialization of a byte vector in BSON format to a JSON value.
 
```cpp
--8<-- "examples/from_bson.cpp"
```

Output:

```json
--8<-- "examples/from_bson.output"
```

Version history

Added in version 3.4.0.

3.8 KiB Raw Blame History