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CDR is a transfer syntax, mapping from data types defined in OMG IDL to a bicanonical, low-level representation for transfer
between agents. CDR has the following features:
• Variable byte ordering -Machines with a common byte order may exchange messages without byte swapping. When communicating machines have different byte order, the message originator determines the message byte order, and the receiver is responsible for swapping bytes to match its native ordering. Each GIOP message (and CDR encapsulation) contains a flag that indicates the appropriate byte order.
• Aligned primitive types -Primitive OMG IDL data types are aligned on their natural boundaries within GIOP messages, permitting data to be handled efficiently by architectures that enforce data alignment in memory.
• Complete OMG IDL Mapping -CDR describes representations for all OMG IDL data types, including transferable pseudo-objects such as TypeCodes. Where necessary, CDR defines representations for data types whose representations are undefined or implementation-dependent in the CORBA Core specifications.