-- Zone.mesa (last edited by: McJones on: January 8, 1981 1:29 PM)

DIRECTORY

Environment USING [Base];

Zone: DEFINITIONS =

BEGIN

-- Types known by clients of the zone allocator

Alignment: TYPE = {a1, a2, a4, a8, a16};

Base: TYPE = Environment.Base; -- for upward compatibility

Handle: TYPE = PRIVATE RECORD[LONG UNSPECIFIED];

SegmentHandle: TYPE = PRIVATE RECORD[UNSPECIFIED];

BlockSize: TYPE = CARDINAL [0..77777B--largest block is 215-1 words--];

-- Useful constants

minimumNodeSize: READONLY BlockSize;

nullSegment: READONLY SegmentHandle;

nil: READONLY Base RELATIVE POINTER;

-- Status returned by Zone operations

Status: TYPE = {okay, noRoomInZone, nonEmptySegment, storageOutOfRange, zoneTooSmall, segmentTooSmall, invalidNode, invalidZone, invalidSegment, nodeLoop, wrongSeal, wrongVersion};

-- Node allocation and deallocation

MakeNode: PROCEDURE [zH: Handle, n: BlockSize, alignment: Alignment ← a1] RETURNS [node: Base RELATIVE POINTER, s: Status];

FreeNode: PROCEDURE [zH: Handle, p: LONG POINTER] RETURNS [s: Status];

SplitNode: PROCEDURE [zH: Handle, p: LONG POINTER, n: BlockSize] RETURNS [s: Status];

NodeSize: PROCEDURE [p: LONG POINTER] RETURNS [n: BlockSize];

-- Zone and segment management

Create: PROCEDURE [storage: LONG POINTER, length: BlockSize, zoneBase: Base, threshold: BlockSize ← minimumNodeSize, checking: BOOLEAN ← FALSE] RETURNS [zH: Handle, s: Status];

AddSegment: PROCEDURE [zH: Handle, storage: LONG POINTER, length: BlockSize] RETURNS [sH: SegmentHandle, s: Status];

RemoveSegment: PROCEDURE [zH: Handle, sH: SegmentHandle] RETURNS [storage: LONG POINTER, s: Status];

Recreate: PROCEDURE [storage: LONG POINTER, zoneBase: Base] RETURNS [zH: Handle, rootNode: Base RELATIVE POINTER, s: Status];

-- Zone and segment attributes

GetAttributes: PROCEDURE [zH: Handle] RETURNS [zoneBase: Base, threshold: BlockSize, checking: BOOLEAN, storage: LONG POINTER, length: BlockSize, next: SegmentHandle];

SetChecking: PROCEDURE [zH: Handle, checking: BOOLEAN] RETURNS [s: Status];

GetSegmentAttributes: PROCEDURE [zH: Handle, sH: SegmentHandle] RETURNS [storage: LONG POINTER, length: BlockSize, next: SegmentHandle];

GetRootNode: PROCEDURE [zH: Handle] RETURNS [node: Base RELATIVE POINTER];

SetRootNode: PROCEDURE [zH: Handle, node: Base RELATIVE POINTER];

END.

LOG

Time: February 21, 1979 10:50 AMBy: LauerAction: Created file

Time: July 18, 1979 4:19 PMBy: KnutsenAction: Added alignment parameter to MakeNode

Time: January 8, 1981 1:29 PMBy: McJonesAction: Added Recreate and RootNode procedures