JXON is a binary format for structured data.
- Simple to understand and use
- Uses modern binary types "as is": little-endian integers, IEEE-754 floats and UTF-8 strings
- Allows storing repeated keys in a special table for reducing memory consumption
JXONandJSONare not mutually exclusive, interchangeability is a design goal
Draft. Format for BigInt is yet to be chosen.
See examples directory. *.jxon files are JXON values,
*.txt are their hex dumps and *.json are their respective JSON equivalents.
- Python — reference implementation (still in development)
JXON value is a sequence of commands. Each command starts with 1 byte header
called head, which may be followed by arguments of the command.
Commands:
Head Arguments Meaning
(Hex)
--------- ---------------------------- ----------------------------------------
0x00-0x7F ERROR: forbidden ASCII characters
0x8? [integer] integer (see below)
0x9? [size] byte* BLOB (arbitrary binary data, also known as byte string)
0xA? [size] utf8char* 0 UTF-8 string
0xB? [size] utf8char* 0 index put UTF-8 string to table[index], 0<=index<128
0xC0-0xEF ERROR: reserved
0xF0 null
0xF1 false
0xF2 true
0xF3 start object
0xF4 start array
0xF5 end object or array
0xF6 0.0 (floating-point zero)
0xF7 float 32-bit IEEE float
0xF8 double 64-bit IEEE float
0xF9 BigInt BigInt large float (mantissa and binary exponent)
0xFA-0xFD ERROR: reserved
0xFE-0xFF ERROR: forbidden UTF-8/16/32 BOMs
Integers (0x8?) and sizes (in 0x9?, 0xA? and 0xB? commands) may be in
one of the following forms:
Head i Arguments Value
Binary
----------- ------- ------------------- ---------------------------------------
b10xx0000 0 0
b10xx0001 1 1
b10xx0010 2 2
b10xx0011 3 3
b10xx0100 4 4
b10xx0101 5 5
b10xx0110 6 6
b10xx0111 7 7
b10xx1000 8 8
b10xx1001 9 9
b10xx1010 10 Int8 Little-endian 8-bits signed integer
b10xx1011 11 Int16 Little-endian 16-bits signed integer
b10xx1100 12 Int32 Little-endian 32-bits signed integer
b10xx1101 13 Int64 Little-endian 64-bits signed integer
b10xx1110 14 BigInt Signed BigInt
b10xx1111 15 -1
Parser should keep up to 128 string values in a special array of strings called table while parsing. Each value in the table has an index in range 0..127. At the beginning of parsing the table should be filled with empty strings.
To store a string to the table command Bi is used. Format of the command is
similar to string value, the only difference is 1-byte index value at the end:
Binary Hex Arguments Meaning
1011iiii Bi <size> utf8char* 0 index put the string to table[index]
(0 <= index < 128)
Values in the table may be overwritten by following "put" commands.
The table is used only for keys. It cannot be used for values.
An array starts with F4 and ends with F5. Between the two must be a
sequence of JXON values.
An object starts with F3 and ends with F5. Between the two bytes must
be a sequence of key-value pairs.
Keys are always strings. They may be specified with an index to the table:
Binary Hex Arguments Meaning
0iiiiiii Use table[index] as the key, where index is the head byte
1010iiii Ai <size> utf8char* 0 Use the specified UTF-8 string as key