oatpp-bob

(oatpp-BinaryOBject - BOB)
Object-Mapper for binary serialization/deserialization.

BOB Format

BOB is basically a regular JSON in which values are written in binary format. It supports JSON data types only - [object, array, string, number(ints and floats), true, false, null]. Thus, JSON and oatpp-BOB are 100% interchangeable.

Format Structure

BOB uses big-endian format (network byte order) to store binary values.

type	description	format
int1	1 - byte signed integer	'1'<1-byte value>
int2	2 - byte signed integer	'2'<2-byte value>
int4	4 - byte signed integer	'4'<4-byte value>
int8	8 - byte signed integer	'8'<8-byte value>
uint1	1 - byte unsigned integer	'b'<1-byte value>
uint2	2 - byte unsigned integer	'i'<2-byte value>
uint4	4 - byte unsigned integer	'I'<4-byte value>
uint8	8 - byte unsigned integer	'L'<8-byte value>
float4	4 - byte float	'f'<4-byte value>
float8	8 - byte float	'd'<8-byte value>
true	boolean true	'+'
false	boolean false	'-'
null	null value	'0'
string1	string with max length of 2^8 - 1 chars	's'<1-byte size><data>
string2	string with max length of 2^16 - 1 chars	'S'<2-byte size><data>
string4	string with max length of 2^32 - 1 chars	'$'<4-byte size><data>
object	sequence of key-value pairs	'{'<key-value pairs>')'
array	sequence of values	'['<values>')'

• Note: <key-value> pairs in object are stored without any delimiters. Each key is encoded as a null-terminated string.
• Note: <values> in array are stored without any delimiters. Each value begins with the type-designating byte (char).

Example - JSONs and their equivalent BOBs

json = '{"key":"value"}'; // size: 15 bytes
bob  = "{key\0s\7value)"; // size: 13 bytes 

json = '{"key1":"value1","key2":5}'; // size: 26 bytes 
bob  = "{key1\0s\6value1key2\0b\5)"; // size: 22 bytes 

Examples in C++

oatpp::String bob("{key\0s\5value)", 13); // <- You have to provide length explicitly because of the '\0' char in the middle of string
auto obj = bobMapper.readFromString<oatpp::Any>(bob);
auto json = jsonMapper.writeToString(obj);
OATPP_LOGD(TAG, "json='%s'", json->c_str()) // <- json='{"key":"value"}'

oatpp::String bob("{key1\0s\6value1key2\0b\5)", 22); // <- You have to provide length explicitly because of the '\0' char in the middle of string
auto obj = bobMapper.readFromString<oatpp::Any>(bob);
auto json = jsonMapper.writeToString(obj);
OATPP_LOGD(TAG, "json='%s'", json->c_str()) // <- json='{"key1":"value1","key2":5}'