AMQP Specification Transport

AMQP Specification.
Derived-types
7 Derived-types
7.1 Domains
An AMQP domain defines a new type with a format identical to another type, but with a restricted range of
values. In some cases a closed set of permitted values is formally restricted to a predetermined set of values,
and in other cases an open set of restricted values is specified.
7.2 Structs
An AMQP struct defines a compound type. That is a type whose format is defined entirely in terms of other
types. Each struct definition includes an ordered sequence of well known fields, each with a specified name,
type, and multiplicity. A struct is encoded as a set of packing flags that indicate which fields are present,
followed by the encoded field data for those fields that are present. Where fields are defined to permit
multiple values, the encoded data for that field starts with a 4 OCTET count indicating how many values are
present.
The first and second octet of packing flags contain presence indicators for fields 1-8 and fields 9-16
respectively. Within each octet the fields map in order from the least significant bit to the most significant
bit. If a packing flag is set the corresponding field MUST be included in the encoded data. If a packing flag
is not set the corresponding field MUST NOT be included in the encoded data. If the struct has fewer
properties than packing flags the extra packing flags are reserved for future extension of the struct and
MUST be set to zero.
Structs are specifically defined by the command, control, and struct definitions within this document. Each
definition includes a unique struct code for use with the struct primitive type as well as the order, name,
type, and multiplicity of the struct fields.
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