-- BTreeSupportDefs May 23, 1980 2:01 PM

BTreeSupportDefs: DEFINITIONS =

BEGIN

FileHandle: TYPE = RECORD[fileH: UNSPECIFIED];

PageHandle: TYPE = RECORD[pageH: POINTER TO ARRAY OF WORD];

PageNumber: TYPE = CARDINAL;

ReadPage: PROCEDURE[fileH: FileHandle, pageN: PageNumber] RETURNS [pageH: PageHandle]; -- does allocation of main memory.

UsePage: PROCEDURE[fileH: FileHandle, pageN: PageNumber] RETURNS [pageH: PageHandle]; -- for when the page has no valid data. Avoids unnecessary disk read if < eof, works for 1 page > eof. does not zero the page.

WritePage: PROCEDURE[fileH: FileHandle, pageN: PageNumber, pageH: PageHandle]; -- deallocates main memory.

ReleasePage: PROCEDURE[pageH: PageHandle]; -- for when page has not been dirtied.

SetLength: PROCEDURE[fileH: FileHandle, pageN: PageNumber]; -- will be used by PruneBTree.

PageSize: PROCEDURE RETURNS[nWords: CARDINAL];

AllocateWords: PROCEDURE[nWords: CARDINAL] RETURNS[POINTER];

FreeWords: PROCEDURE[POINTER];

END.

Edit Log

Change: May 13, 1980 1:04 PM: KK: interface changes so the message system and Juniper can both use the btree package.