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XBin Format Reference

The XBin (XINA Binary) format provides a XINA standard binary format for time based data files. It uses the file extension xbin.

The xbin format organizes key-value data by time. The data content is a series of rows in ascending time order, with each row having a single microsecond precision Unix time, unique within the file.

Segment Format

XBin data is often encoded in segments, which are defined by an initial signed integer byte length, then that number of bytes. These are referred to in this document as:

  • seg1 (up to 127 bytes)
  • seg2 (up to 32,767 bytes)
  • seg4 (up to 2,147,483,647 bytes)

If the length value of a segment is zero there is no following data and the value is considered empty.

Value Format

Each value starts with a 1 byte signed integer indicating the value type, followed by additional byte(s) containing the value itself, as applicable.

Value Type Definition

Code Value Length Description
0 null 0 literal null / empty string
1 reference dict index variable see below
2 true boolean literal 0
3 false boolean literal 0
4 1 byte signed integer 1
5 2 byte signed integer 2
6 4 byte signed integer 4
7 8 byte signed integer 8
8 4 byte floating point 4
9 8 byte floating point 8
10 string1 variable seg1 UTF-8 encoded string
11 string2 variable seg2 UTF-8 encoded string
12 string4 variable seg4 UTF-8 encoded string
13 json1 variable seg1 UTF-8 encoded JSON
14 json2 variable seg2 UTF-8 encoded JSON
15 json4 variable seg4 UTF-8 encoded JSON
16 xstring1 variable seg1 xstring
17 xstring2 variable seg2 xstring
18 xstring4 variable seg4 xstring
19 xjsonarray1 variable seg1 xjson array
20 xjsonarray2 variable seg2 xjson array
21 xjsonarray4 variable seg4 xjson array
22 xjsonobject1 variable seg1 xjson array
23 xjsonobject2 variable seg2 xjson array
24 xjsonobject4 variable seg4 xjson array
(-128, -1) code dict index 0 see below

XString Format

The xstring value type allows chaining mutliple encoded values to be interpretted as a string. The xstring segment length must be the total number of bytes of all encoded values in the string.

XJSON Array Format

The xjsonarray value type allows chaining mutliple encoded values to be interpretted as a JSON array. The xjsonarray segment length must be the total number of bytes of all encoded values in the array.

UUID

The file starts with a 16 byte binary encoded UUID. This is intended to uniquely identify the file, but the exact implementation and usage beyond this is not explicitly defined as part of the format definition. For XINA purposes two xbin files with the same UUID would be expected to be identical.

Header

This is followed by a seg4, which contains a single JSON object with UTF-8 encoding. It may be empty. This is currently a placeholder with no defined parameters.

Rows

Each row starts with an 8 byte signed integer containing Unix time with microsecond precision. This is followed by a 4 byte unsigned integer denoting the length of the row in bytes.

Values