Null represents a null pointer.

The byte 'N' represents the null pointer.

null values are allowed in place of any string, xml, binary, list, map, or remote.

The byte 'F' represents false and the byte 'T' represents true.

A 32-bit signed integer. An integer is represented by the byte 'I' followed by the 4-bytes of the integer in big-endian order

A 64-bit signed integer. An long is represented by the byte 'L' followed by the 8-bytes of the integer in big-endian order

A 64-bit IEEE floating pointer number.

Date represented by a 64-bits long of milliseconds since the epoch.

A 16-bit unicode character string encoded in UTF-8. Strings are encoded in chunks. 'S' represents the final chunk and 's' represents any initial chunk. Each chunk has a 16-bit length value.

The length is the number of characters, which may be different than the number of bytes.

An XML document encoded as a 16-bit unicode character string encoded in UTF-8. XML data is encoded in chunks. 'X' represents the final chunk and 'x' represents any initial chunk.

Each chunk has a 16-bit length value. The length is the number of characters, which may be different than the number of bytes.

A binary value.

Binary data is encoded in chunks. 'B' represents the final chunk and 'b' represents any initial chunk. Each chunk has a 16-bit length value.

An ordered list, like an array. All lists have a type string, a length, a list of objects, and a trailing 'z'. The type string may be an arbitrary UTF-8 string understood by the service (often a Java class name, but this isn't required.) The length may be -1 to indicate that the list is variable length.

Each list item is added to the reference list to handle shared and circular elements. See the ref element.

Any parser expecting a list must also accept a null or a shared ref.

Represents serialized objects and Maps. The type element describes the type of the map. Objects are represented by a map from field names to their values and type is the class of the object itself.

The type may be empty, i.e. a zero length. The parser is responsible for choosing a type if one is not specified. For objects, unrecognized keys will be ignored.

Each map is added to the reference list. Any time the parser expects a map, it must also be able to support a null or a ref.

An integer referring to a previous list or map instance. As each list or map is read from the input stream, it is assigned the integer position in the stream, i.e. the first list or map is '0', the next is '1', etc. A later ref can then use the previous object. Writers are not required to generate refs, but parsers must be able to recognize them.

ref can refer to incompletely-read items. For example, a circular linked-list will refer to the first link before the entire list has been read.

A possible implementation would add each map and list to an array as it's read. The ref will return the corresponding object from the array. To support circular structures, the implementation would store the map or list immediately, before filling in the object's contents.

Each <list> or <array> is stored into an array as it is parsed. <ref> selects one of the stored objects. The first object is numbered '0'.

A reference to a remote object. The remote has a type and a utf-8 string representing the object's URL.