2.6.1.1.1 Allocating Space from the PST

Allocating space directly from the PST file for higher-level operations.

Requirement level	Actions
Required	MUST check the fAMapValid value in the ROOT structure before proceeding (section 2.6.1.3.7). Each allocation MUST NOT exceed 8 kilobytes (8192 bytes) in size. The corresponding AMap MUST be updated to reflect the allocation (section 2.2.2.7.2). The cbAMapFree and cbPMapFree fields in the HEADER.ROOT structure MUST be updated to reflect the allocation.
Recommended	Use the DList, PMap, FMap, FPMap as optimizations.
Optional	Update the DList. Update the PMap, FMap, FPMap.

Requirement level

Actions

Required

MUST check the fAMapValid value in the ROOT structure before proceeding (section 2.6.1.3.7).

Each allocation MUST NOT exceed 8 kilobytes (8192 bytes) in size.

The corresponding AMap MUST be updated to reflect the allocation (section 2.2.2.7.2).

The cbAMapFree and cbPMapFree fields in the HEADER.ROOT structure MUST be updated to reflect the allocation.

Recommended

Use the DList, PMap, FMap, FPMap as optimizations.

Optional

Update the DList.

Update the PMap, FMap, FPMap.

Possible side effects:

Scenario	Impact
Free slot of required size not found	The PST File needs to grow. See section 2.6.1.1.2 for additional considerations.

Additional resources