Niels Lohmann
4b35877ae5
Add an "Extension types (ext, fixext)" section to the MessagePack page: ext/fixext are read as binary, the signed ext type is exposed as an unsigned subtype 0..255 (-1 reads as 255), Timestamp is not interpreted, subtypes are always written as ext/fixext, and subtypes above 255 throw out_of_range.415. Add the 0xC1 row to the deserialization table, note that duplicate keys keep the last value, and correct the NaN/Infinity explanation, the "31 bytes / 15 elements" wording, the ill-formed UTF-8 sentence, and the generic 0xC1-key error message. Add fixext16 and the unsigned subtype mapping to binary_t.md and binary_values.md, reword "maximum of the MessagePack ext type" in to_msgpack.md and exceptions.md, and mark MessagePack deserialization as incomplete (non-string keys) in the binary formats overview. Signed-off-by: Niels Lohmann <mail@nlohmann.me>
3.9 KiB
3.9 KiB
Binary Formats
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
- BJData (Binary JData),
- BON8 (Binary Object Notation 8),
- BSON (Binary JSON),
- CBOR (Concise Binary Object Representation),
- MessagePack, and
- UBJSON (Universal Binary JSON)
to efficiently encode JSON values to byte vectors and to decode such vectors.
Comparison
Completeness
| Format | Serialization | Deserialization |
|---|---|---|
| BJData | complete | complete |
| BON8 | incomplete: no unsigned integers above int64 | complete |
| BSON | incomplete: top-level value must be an object | incomplete, but all JSON types are supported |
| CBOR | complete | incomplete, but all JSON types are supported |
| MessagePack | complete | incomplete, but all JSON types are supported |
| UBJSON | complete | complete |
Binary values
| Format | Binary values | Binary subtypes |
|---|---|---|
| BJData | not supported | not supported |
| BON8 | not supported | not supported |
| BSON | supported | supported |
| CBOR | supported | supported |
| MessagePack | supported | supported |
| UBJSON | not supported | not supported |
See binary values for more information.
Sizes
| Format | canada.json | twitter.json | citm_catalog.json | jeopardy.json |
|---|---|---|---|---|
| BJData | 53.2 % | 91.1 % | 78.1 % | 96.6 % |
| BJData (size) | 58.6 % | 92.1 % | 86.7 % | 97.4 % |
| BJData (size+type) | 58.6 % | 92.1 % | 86.5 % | 97.4 % |
| BON8 | 50.5 % | 83.8 % | 63.5 % | 87.5 % |
| BSON | 85.8 % | 95.2 % | 95.8 % | 106.7 % |
| CBOR | 50.5 % | 86.3 % | 68.4 % | 88.0 % |
| MessagePack | 50.5 % | 86.0 % | 68.5 % | 87.9 % |
| UBJSON | 53.2 % | 91.3 % | 78.2 % | 96.6 % |
| UBJSON (size) | 58.6 % | 92.3 % | 86.8 % | 97.4 % |
| UBJSON (size+type) | 55.9 % | 92.3 % | 85.0 % | 95.0 % |
Sizes compared to minified JSON value; the smallest size per file is printed in bold.
See also
- Binary values - binary values and subtypes
- to_cbor / from_cbor, to_msgpack / from_msgpack, to_bson / from_bson, to_ubjson / from_ubjson, to_bjdata / from_bjdata, to_bon8 / from_bon8 - the conversion functions
- Parsing untrusted input
- SAX interface - decode binary formats without building a value