<> <> <> <> <> <> <> <> DIRECTORY Atom USING [EmptyAtom], Basics USING [BITXOR, LowHalf], FileOps USING [FormatIndex, LooksIndex, numFormats, numLooks, numProps, PropIndex], PGSupport USING [FormatHashIndex, formatHashSize, LooksHashIndex, looksHashSize, noLooks, PGF, PGFBody, PropHashIndex, propHashSize], PrincOps USING [zXOR], TextLooks USING [Looks, LooksBytes, noLooks]; PGSupportImpl: CEDAR MONITOR IMPORTS Atom, Basics EXPORTS PGSupport = BEGIN OPEN PGSupport; Looks: TYPE ~ TextLooks.Looks; noLooks: Looks ~ TextLooks.noLooks; PropIndex: TYPE ~ FileOps.PropIndex; FormatIndex: TYPE ~ FileOps.FormatIndex; LooksIndex: TYPE ~ FileOps.LooksIndex; <<-- PGF is the file-level structure for put/get>> CreatePGF: PUBLIC PROC RETURNS [pgf: PGF] = { pgf _ AllocPGF[]; pgf.looksTable[0] _ TextLooks.noLooks; pgf.looksNext _ 1; -- reserve 0 for noLooks FOR i:LooksHashIndex IN LooksHashIndex DO pgf.looksHashKeys[i].looks _ TextLooks.noLooks; ENDLOOP; pgf.formatTable[0] _ NIL; FOR i:FormatHashIndex IN FormatHashIndex DO pgf.formatHashKeys[i].formatName _ NIL; ENDLOOP; pgf.formatNext _ 1; -- reserve 0 for null formatname pgf.propNext _ 1; --reserve 0 for NIL FOR i:PropHashIndex IN PropHashIndex DO pgf.propHashKeys[i].propname _ NIL; ENDLOOP; [] _ EnterProp[$Prefix, pgf]; -- preload system atoms [] _ EnterProp[$Postfix, pgf]; }; pgf1, pgf2, pgf3: PGF _ NIL; AllocPGF: ENTRY PROC RETURNS [pgf: PGF] = { ENABLE UNWIND => NULL; IF pgf3 # NIL THEN { pgf _ pgf3; pgf3 _ NIL } ELSE IF pgf2 # NIL THEN { pgf _ pgf2; pgf2 _ NIL } ELSE IF pgf1 # NIL THEN { pgf _ pgf1; pgf1 _ NIL } ELSE pgf _ NEW[PGFBody] }; FreePGF: PUBLIC ENTRY PROC [pgf: PGF] = { ENABLE UNWIND => NULL; IF pgf3 = pgf OR pgf2 = pgf OR pgf1 = pgf THEN ERROR; IF pgf3 = NIL THEN pgf3 _ pgf ELSE IF pgf2 = NIL THEN pgf2 _ pgf ELSE IF pgf1 = NIL THEN pgf1 _ pgf }; BadIndex: PUBLIC ERROR = CODE; RetrieveFormatName: PUBLIC PROC [index: FormatIndex, pgf: PGF] RETURNS [formatName: ATOM] = { IF index >= pgf.formatNext THEN ERROR BadIndex; RETURN [pgf.formatTable[index]] }; RetrieveLooks: PUBLIC PROC [index: LooksIndex, pgf: PGF] RETURNS [looks: Looks] = { IF index >= pgf.looksNext THEN ERROR BadIndex; RETURN [pgf.looksTable[index]] }; RetrieveProp: PUBLIC PROC [index: PropIndex, pgf: PGF] RETURNS [propname: ATOM] = { IF index >= pgf.propNext THEN ERROR BadIndex; RETURN [pgf.propTable[index]] }; Munch: PROC [key: ATOM] RETURNS [CARDINAL] = TRUSTED MACHINE CODE { PrincOps.zXOR; }; true: BOOL[TRUE..TRUE] ~ (SIZE[ATOM]-SIZE[CARDINAL] = 1); EnterFormatName: PUBLIC PROC [formatName: ATOM, pgf: PGF] RETURNS [ok: BOOL, index: FileOps.FormatIndex] = { next: NAT _ pgf.formatNext; initloc, loc: NAT; IF formatName = NIL OR formatName = Atom.EmptyAtom[] THEN RETURN [TRUE, 0]; -- reserved loc _ initloc _ Munch[formatName] MOD formatHashSize; DO SELECT pgf.formatHashKeys[loc].formatName FROM formatName => RETURN [TRUE, pgf.formatHashVals[loc].index]; NIL => EXIT; -- this is an unused entry ENDCASE; SELECT (loc _ loc+1) FROM formatHashSize => IF (loc _ 0)=initloc THEN ERROR; initloc => ERROR; -- should never have full table ENDCASE; ENDLOOP; IF next < FileOps.numFormats THEN -- room left in table BEGIN pgf.formatTable[next] _ formatName; pgf.formatNext _ next+1; pgf.formatHashKeys[loc].formatName _ formatName; pgf.formatHashVals[loc].index _ LOOPHOLE[next]; END; RETURN [FALSE, 0] }; -- index irrelevant in this case EnterLooks: PUBLIC PROC [looks: TextLooks.Looks, pgf: PGF] RETURNS [ok: BOOL, index: FileOps.LooksIndex] = { next: NAT _ pgf.looksNext; initloc, loc: NAT; IF looks = TextLooks.noLooks THEN RETURN [TRUE, 0]; -- reserved loc _ initloc _ LOOPHOLE[ Basics.BITXOR[ LOOPHOLE[looks, TextLooks.LooksBytes].byte0, Basics.BITXOR[LOOPHOLE[looks, TextLooks.LooksBytes].byte1, LOOPHOLE[looks, TextLooks.LooksBytes].byte2]],NAT] MOD looksHashSize; DO SELECT pgf.looksHashKeys[loc].looks FROM looks => RETURN [TRUE, pgf.looksHashVals[loc].index]; TextLooks.noLooks => EXIT; -- this is an unused entry ENDCASE; SELECT (loc _ loc+1) FROM looksHashSize => IF (loc _ 0)=initloc THEN ERROR; initloc => ERROR; -- should never have full table ENDCASE; ENDLOOP; IF next < FileOps.numLooks THEN -- room left in table BEGIN pgf.looksTable[next] _ looks; pgf.looksNext _ next+1; pgf.looksHashKeys[loc].looks _ looks; pgf.looksHashVals[loc].index _ LOOPHOLE[next]; END; RETURN [FALSE, 0] }; -- index irrelevant in this case EnterProp: PUBLIC PROC [propname: ATOM, pgf: PGF] RETURNS [ok: BOOL, index: FileOps.PropIndex] = { next: NAT _ pgf.propNext; initloc, loc: NAT; IF propname = NIL THEN RETURN [TRUE, 0]; -- reserved loc _ initloc _ (LOOPHOLE[Basics.LowHalf[LOOPHOLE[propname]],NAT] / 16) MOD propHashSize; DO SELECT pgf.propHashKeys[loc].propname FROM propname => RETURN [TRUE, pgf.propHashVals[loc].index]; NIL => EXIT; -- this is an unused entry ENDCASE; SELECT (loc _ loc+1) FROM propHashSize => IF (loc _ 0)=initloc THEN ERROR; initloc => ERROR; -- should never have full table ENDCASE; ENDLOOP; IF next < FileOps.numProps THEN -- room left in table BEGIN pgf.propTable[next] _ propname; pgf.propNext _ next+1; pgf.propHashKeys[loc].propname _ propname; pgf.propHashVals[loc].index _ LOOPHOLE[next]; END; RETURN [FALSE, 0] }; -- index irrelevant in this case END.