File: DBIndexOp.mesa
Copyright © 1985 by Xerox Corporation. All rights reserved.
Willie-Sue, February 15, 1985 3:46:17 pm PST
Donahue, May 22, 1986 12:04:35 pm PDT
Page: TYPE = DBIndex.Page;
State: TYPE = DBIndex.State;
IndexKey: TYPE = DBIndex.IndexKey;
OverFlow: PROC [p: Page, key: REF TEXT] RETURNS [BOOLEAN];
EntrySize:
PROC [p: Page, i:
CARDINAL]
RETURNS [
CARDINAL];
Returns the size of the entry: key plus value
RopeForKey: PROC[key: IndexKey] RETURNS[REF TEXT];
SplitPage:
PROC [p: Page, loc:
CARDINAL, insertSize:
INTEGER]
RETURNS [splitLoc:
CARDINAL, splitKey:
REF TEXT, overflow: Page];
SplitLeaf:
PROC [p: Page, key:
REF TEXT, value:
LONG
CARDINAL]
RETURNS [Page,
REF TEXT];
The page overflows if we insert <key, value> pair. We allocate a page to the right of p and moves contents, and insert <key, value> at the same time.
SplitInternal:
PROC [p: Page, insertLoc:
CARDINAL, key:
REF TEXT, value:
LONG
CARDINAL]
RETURNS [Page, REF TEXT];
InsertInInternalPage:
PROC [p: Page, i:
CARDINAL, newPage:
LONG
CARDINAL, newKey:
REF TEXT]
RETURNS [State, Page,
REF TEXT];
DeleteFromLeafPage:
PROC [p: Page, key:
REF TEXT, tid: DBCommon.TID]
RETURNS [State, Page,
REF TEXT];
MergeInLeafPage:
PROC [p: Page, son: Page, index:
CARDINAL]
RETURNS [State, Page,
REF TEXT];
ChangeKey:
PROC[p: Page, newKey:
REF TEXT, index:
CARDINAL]
RETURNS[state: State, overflow: Page, key:
REF TEXT];
Sets indexed key in leaf page p to be newKey.
MoveScanIndexLeft:
PUBLIC
PROC [from, to: Page, nentries:
CARDINAL];
"from" is to the right of "to"
moves the first "nentries" in "from" to "to"
MoveScanIndexRight:
PUBLIC
PROC [from, to: Page, after:
CARDINAL];
moves the scan index on "from" to "to", if the index is greater than "after"
"to" is empty
DecrementScanIndex:
PROC [page: Page, atOrAfter:
CARDINAL];
Decrements any effected scan indices by one, if they are on "page" with index greater or equal to "atOrAfter"
IncrementScanIndex:
PUBLIC
PROC [page: Page, atOrAfter:
CARDINAL, howMuch:
CARDINAL ← 1];
Increments any effected scan indices by howMuch, if they are on "page" with index greater or equal to "atOrAfter"
By Cattell September 22, 1982 9:20 am: Re-organized DBIndex interfaces for isolating page writes. Moved some procs from here to DBIndexMod.
Changed by Willie-Sue on February 15, 1985
made Cedar, added tioga formatting