-- VultureOps.mesa
-- Scavanger for Mail Archive files.
-- Maurice Herlihy August 7, 1982


DIRECTORY
    BodyDefs,
    Rope,
    Space,
    VultureDefs;

VultureOps: DEFINITIONS
    IMPORTS Rope, Space, BodyDefs
    = {
        
    -- Public types.
    Item: TYPE = LONG POINTER TO BodyDefs.ItemHeader;
    
    -- Opaque types
    ItemStream: TYPE = REF ItemStreamRep;
    ItemStreamRep: TYPE;
    DirStream: TYPE = REF DirStreamRep;
    DirStreamRep: TYPE;
    
    ROPE: TYPE = Rope.ROPE;
EndOfStream:  ERROR;
BadFormat: ERROR;
OpenDirStream: PROC [space: Space.Handle] RETURNS [dirstream: DirStream] -- Signals EndOfStream --;
-- Creates a DirStream from given space. EndOfStream => file VERY broken.
NextDirectory: PROC [dirSteam: DirStream] RETURNS [directory: VultureDefs.Directory]
    -- Signals EndOfStream --;
<<-- Return next directory in stream.>>
CloseDirStream: PROC [dirSteam: DirStream];
-- Mark any unseen directories as deleted.

OpenItemStream: PROC [space: Space.Handle] RETURNS [ItemStream]-- Signals EndOfStream --;
-- Creates an item stream from given space.

NextItem: PROC [stream: ItemStream] RETURNS [item: Item] -- Signals EndOfStream, BadFormat --;
<<-- Returns next item in stream.
>>
FindPostmark: PROC [stream: ItemStream] RETURNS [INT] -- Signals EndOfStream --;
<<-- Moves stream ahead to next apparent postmark item.>>
NoMoreItems: PROC [stream: ItemStream] RETURNS [BOOL];
<<-- Any items left in the stream?>>
ParseItem: PUBLIC PROC [item: Item] RETURNS [ROPE];
<<-- Prints item type.>>
Reset: PUBLIC PROC [stream: ItemStream, address: INT] -- signals EndOfStream--;
<<-- Sets current stream address to address.>>
Current: PUBLIC PROC [stream: ItemStream] RETURNS [INT];
<<-- Current stream address>>
     }.