3.1.5.4.3.2.3 Bitmask Command (0x42)
The decoder only encounters the Bitmask command, as specified in section 2.2.2.6.3, when there are five bytes in the common byte stack. The server SHOULD send the client an RpcFormat error (0x000004B6), and MAY send the client a FormatError error (0x000004ED )<29>, as specified in [MS-OXCDATA] section 2.4.1, if the decoder encounters the Bitmask command when there are more or fewer than five bytes in the common byte stack.
For more details about the format of the Bitmask command and its fields, see section 2.2.2.6.3.
Using the StartingValue and the Bitmask fields, as specified in section 2.2.2.6.3, a set of low-order bytes can be produced. For more details about decoding the Bitmask field to produce individual low-order values, see section 3.1.5.4.3.1.3. Each low-order byte MUST be combined with the required five high-order bytes on the common byte stack to form a complete 6-byte GLOBCNT structure, as specified in section 2.2.2.5, which MUST be added to the GLOBSET structure.