[Cyan]<Cedar6.0>FS>FSPkgRefImpl.mesa!2

FSPkgRefImpl.mesa

Last Edited by:

Bob Hagmann February 4, 1985 9:40:26 am PST

Schroeder, November 15, 1983 1:35 pm

DIRECTORY

FSLock;

FSPkgRefImpl: CEDAR MONITOR

EXPORTS FSLock

= BEGIN

Exported to FSOpenFile

RecordREF: PUBLIC ENTRY PROC [r: REF] =

BEGIN

p: REF PRTEntry = NEW [PRTEntry];

hash: CARDINAL = Hash[r];

p.ref ← r;

p.chain ← prt[hash];

prt[hash] ← p;

recorded ← recorded + 1;

END;

RemoveREF: PUBLIC ENTRY PROC [r: REF] =

BEGIN

hash: CARDINAL = Hash[r];

p, q: REF PRTEntry;

q ← prt[hash];

IF q.ref = r

THEN prt[hash] ← q.chain

ELSE DO

p ← q;

q ← q.chain;

IF q.ref = r THEN {p.chain ← q.chain; EXIT};

ENDLOOP;

q.ref ← NIL;

removed ← removed + 1;

END;

Package Reference Table

buckets: CARDINAL = 251;

PackageReferenceTable: TYPE = ARRAY [0..buckets) OF REF PRTEntry;

PRTEntry: TYPE = RECORD [chain: REF PRTEntry, ref: REF];

prt: REF PackageReferenceTable ← NEW [PackageReferenceTable ← ALL[NIL]];

Hash: PROC [r: REF] RETURNS [CARDINAL] = INLINE

{ RETURN [ LOOPHOLE[r, LONG CARDINAL] MOD buckets] };

PRT statistics

recorded, removed: INT ← 0;

Stats: ENTRY PROC RETURNS [items, longestChain: INT, chains: ARRAY [0..10] OF CARDINAL] =

BEGIN

items ← 0;

longestChain ← 0;

chains ← ALL[0];

FOR i: CARDINAL IN [0 .. buckets) DO

chainLength: INT ← 0;

cIndex: CARDINAL;

FOR p: REF PRTEntry ← prt[i], p.chain UNTIL p = NIL DO

chainLength ← chainLength + 1;

ENDLOOP;

items ← items + chainLength;

IF chainLength > longestChain THEN longestChain ← chainLength;

cIndex ← MIN [chainLength, 10];

chains[cIndex] ← chains[cIndex] + 1;

ENDLOOP;

END;

END.

Bob Hagmann February 4, 1985 9:40:07 am PST