forked from NPM/numass-framework
3.7 KiB
3.7 KiB
| content_type | title | chapter | ordering | label | published |
|---|---|---|---|---|---|
| doc_shard | Binary meta | envelope | 50 | binary_meta | false |
Binary meta format is made to limit size and simplify parsing to automatic messages. The notation for the node looks the following way (all numeric values use BigEndian encoding):
<br>
All strings are encoded in a following way: 2 bytes for string length, byte array of given length representing UTF-8 encoded string.
<br>
1. Meta name as string.
2. 2 bytes unsigned integer representing the number of values in the node. Could be zero.
3. For each of values an encoded name of the value and then:
* `0` for Null value.
* `T` for `TIME` value, followed by two unsigned long values representing epoch second and nanosecond adjustment.
* `S` for `STRING` value followed by encoded string.
* `D` for double based `NUMBER` followed by double (double encoding specified by [Java serialization](https://docs.oracle.com/javase/8/docs/api/java/io/DataOutput.html#writeDouble-double-)).
* `I` for integer based `NUMBER` followed by signed 4-bytes integer value.
* `B` for [`BigDecimal`](https://docs.oracle.com/javase/8/docs/api/java/math/BigDecimal.html) based `NUMBER` followed by 2-byte unsigned integer defining the number of bytes in representation, bytes themselves and 4-byte scale factor.
* `+` for boolean `true`.
* `-` for boolean `false`.
* `L` for list value and then 2-byte list size followed by sequence of values (as in item 3, but without a name).
4. 2 bytes unsigned integer representing the number of child nodes in this node. Could be zero.
5. For each of child nodes:
* child node name,
* 2-byte unsigned integer representing number of children with this name.
* The sequence of nodes with given name encoding like the root node, but without name.