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Recursive Typed and Length-prefixed Object Encoding (RTL)

[TOC]

summary

header code pattern
single byte 0xxxxxxx
zero value/false of bool 10000000
true of bool 10000001
empty value 10000010
reserved 10000011
reserved 100001xx
array(single byte header) 1001xxxx
array(multi bytes header) 10001xxx
positive numeric(single byte header) 10100xxx
negative numeric(single byte header) 10101xxx
positive numeric(multi bytes header) big.Int 10110xxx
negative numeric(multi bytes header) big.Int 10111xxx
string = (array of bytes)(single byte header) 110xxxxx
string = (array of bytes)(multi bytes header) 11100xxx
struct version(single byte value) 1111xxxx
struct version(single byte header) 11101xxx

single byte

one byte for byte value <= 127 (0x7F)

basic value

zero value

zero value of all type(nil for pointer/slice/map, false of boolean,"" for string, empty for array, 0 for numeric)

true of bool

true value of bool type

emtpy value

empty value of slice, map

array value

  • array: followed by elements in array, byte array excluded (use string instead).

  • map: even index is the key, odd index is the value

  • struct: one property of the struct is an element in the array

single byte header

  • bit[7-4]:'1001'
  • bit[3-0]: the number of the length of the array. '0000': 16bytes, '0001': 1byte, '0010': 2bytes,...,'1111': 15bytes
  • empty array is a zero value, use zero value ['10000000'] instead
  • followed by bytes in array from lower index to upper index

multi byte header

  • bit[7-3]='10001', bit[2-0] is the length of the number of the elements of the array, followed by

bit[2-0]=len(trimPrefixZeros(hex(len(array))))

  • max bytes in the length number is 8: '000': 8bytes, '001':1byte, '010':2bytes,...,'111':7bytes
  • empty array is a zero value, use zero value ['10000000'] instead
  • the max number of elements in the array is $2^{8*8}$
  • followed by big-endian prefix-zero-trimed hexadecimal bytes of the length
  • followed by bytes in array from lower index to upper index

Numeric

Signed and unsigned integer, float, big.Int values are supported. We use one bit to identify the positive and negative of the number.

single byte header

  • bit[7-4]: '1010'
  • bit[3]: '0': positive number, '1': negative number
  • bit[2-0]: the number of the hexadecimal bytes of the number. '000': 8bytes, '001':1byte, '010':2bytes,...,'111':7bytes.
  • zero byte not support, use zero value ['10000000'] instead
  • followed by big-endian prefix-zero-trimed hexadecimal bytes of the absolute value of the number.
  • for int/int8/int16/int32/int64/uint/uint8/uint16/uint32/uint64/float32/float64 and all there aliases

multi bytes header

  • bit[7-4]: '1011'
  • bit[3]: '0': positive number, '1': negative number
  • bit[2-0]: the number of the hexadecimal bytes of length of the number. '000': 8bytes, '001':1byte, '010':2bytes,...,'111':7bytes
  • zero byte not support, use zero value ['10000000'] instead
  • the max bytes length of the number is: $2^{8*8}$
  • followed by big-endian prefix-zero-trimed hexadecimal bytes of the number of the length.
  • followed by hexadecimal bytes of the number
  • for big.Int

string & byte array

single byte header

  • bit[7-5]: '110'
  • bit[4-0]: the number of the bytes in string. '00000': 32bytes, '00001': 1byte, '00010': 2bytes,..., '11111': 31bytes
  • zero byte string is an empty string, use zero value ['10000000'] instead

multi bytes header

  • bit[7-3]: '11100'
  • bit[2-0]: the number of the bytes of the number of the bytes in string. max number of bytes is 8, '000': 8bytes, '001':1byte, '010':2bytes,...,'111':7bytes.
  • zero byte string is an empty string, use zero value ['10000000'] instead
  • the max length of the string is: $2^{8*8}$
  • followed by big-endian prefix-zero-trimed hexadecimal bytes of the number of the length
  • followed by bytes in UTF-8 of the string

struct version

struct version is an unsigned number to distinguish between different version of struct stream data.

single byte value

  • bit[7-4]: '1111'
  • bit[3-0]: the version number of the struct, '0000'-'1111' means version 0 to 15
  • default struct version is 0
  • struct version absentness means version equals 0

single byte header

  • bit[7-3]: '11101'
  • bit[2-0]: the number of the bytes of the version number. Max number of bytes is 8, '000': 8bytes, '001':1byte, '010':2bytes, ..., '111':7bytes.
  • followed by big-endian prefix-zero-trimed hexadecimal bytes of the version number
  • the max version number is $2^{8*8}$