Smile (data interchange format)
| Filename extension |
.sml |
|---|---|
| Internet media type |
application/x-jackson-smile[1] (proposed) |
| Type of format | Data interchange |
| Extended from | JSON |
| Standard | no RFC yet |
| Website | wiki |
Smile is a computer data interchange format based on JSON. It can also be consider a binary serialization of generic JSON data model, which means that tools that operation on JSON may be used with Smile as well, as long as proper encoder/decoder exists for tool to use. The name comes from first 2 bytes of the 4 byte header, which consist of Smiley ":)" followed by a linefeed: choice made to make it easier to recognize Smile-encoded data files using textual command-line tools.
Efficiency
Compared to JSON, Smile is both more compact and more efficient to process (both to read and write). Part of this is due to more efficient binary encoding (similar to BSON and UBJSON), but an additional feature is optional use of back references for property names and values. Back referencing allows replacing of property names and/or short (64 bytes or less) String values with 1- or 2-byte reference ids.
Implementations
Libraries known to support Smile include:
- Jackson (Java) (with Smile dataformat module)
- libsmile (C/C++; wrappers for Ruby, Perl)