2.4.7 Named Property Lookup Map

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The mapping between NPIDs and property names is done using a special Name-to-ID-Map in the PST, with a special NID of NID_NAME_TO_ID_MAP (0x61). There is one Name-to-ID-Map per PST. From an implementation point of view, the Name-to-ID-Map is a standard PC with some special properties. Specifically, the properties in the PC do not refer to real property identifiers, but instead point to specific data sections of the Name-to-ID-Map.

A named property is identified by a (GUID, identifier) value pair, otherwise known as the property name. The identifier can be a string or a 16-bit numerical value. The GUID value identifies the property set to which the property name is associated. Well-known property names and a list of property set GUIDs are specified in [MS-OXPROPS].

The Name-to-ID-Map (NPMAP) consists of several components: an Entry Stream, a GUID Stream, a String Stream, and a hash table to expedite searching. The following are the data structures used for the NPMAP.