DIRECTORYRopeEditingAlloc,Rope,RopeReader,RopeFrom;RopeEditingAllocImpl: CEDAR MONITORIMPORTS RopeReaderEXPORTS RopeEditingAlloc =BEGIN OPEN RopeEditingAlloc;charsPerArray: NAT = RopeReader.charsPerArray;wordsPerArray: NAT = charsPerArray/2;charsArray: Chars _ NIL; -- current shared array of charscharsRemaining: NAT _ 0; -- amount of room remaining in current chars arraycharsRope: ROPE; -- rope pointing to current chars arrayAllocChars: PUBLIC ENTRY PROC [len: NAT]RETURNS [chars: Chars, start: NAT, base: ROPE] = {IF len > charsRemaining THEN {IF len > charsPerArray THEN ERROR;IF charsPerArray-len < charsRemaining THEN { -- keep the current onechars _ NEW[CharsArray]; start _ 0;base _ RopeReader.CharsRope[chars];RETURN };charsArray _ NEW[CharsArray]; charsRemaining _ charsPerArray;charsRope _ RopeReader.CharsRope[charsArray] };chars _ charsArray;start _ charsPerArray-charsRemaining;charsRemaining _ charsRemaining-len;base _ charsRope };AllocWords: PUBLIC ENTRY PROC [nwords: NAT]RETURNS [chars: Chars, start: NAT, base: ROPE] = {wordsRemaining: NAT;IF nwords > (wordsRemaining _ charsRemaining/2) THEN {IF nwords > wordsPerArray THEN ERROR;IF wordsPerArray-nwords < wordsRemaining THEN {chars _ NEW[CharsArray]; start _ 0;base _ RopeReader.CharsRope[chars];RETURN };charsArray _ NEW[CharsArray];wordsRemaining _ wordsPerArray;charsRope _ RopeReader.CharsRope[charsArray] };chars _ charsArray;start _ (wordsPerArray-wordsRemaining)*2;charsRemaining _ (wordsRemaining-nwords)*2;base _ charsRope };TryAllocAdjacent: PUBLIC ENTRY PROC [base: ROPE, start: NAT, len: NAT]RETURNS [ok: BOOLEAN, chars: Chars] = {IF base=charsRope ANDstart=charsPerArray-charsRemaining ANDcharsRemaining >= len THEN {charsRemaining _ charsRemaining-len; RETURN [TRUE, charsArray]};RETURN [FALSE, charsArray]};blockSize: NAT = 512;blk1, blk2: REF TEXT; -- shared buffersGetBlock: PUBLIC ENTRY PROC RETURNS [blk: REF TEXT] = {IF blk2 # NIL THEN { blk _ blk2; blk2 _ NIL }ELSE IF blk1 # NIL THEN { blk _ blk1; blk1 _ NIL }ELSE blk _ NEW[TEXT[blockSize]];blk.length _ 0 };FreeBlock: PUBLIC ENTRY PROC [blk: REF TEXT] = {IF blk2 = NIL THEN blk2 _ blk ELSE IF blk1 = NIL THEN blk1 _ blk };END.  |  -- RopeEditingAllocImpl.Mesa; written by Bill Paxton,  March 1981-- edited by Bill Paxton, July 11, 1983 10:58 am-- edited by McGregor, February 8, 1983 11:07 am-- returns chars array & starting index to fill with characters-- and a rope that points to that substring of the chars array-- ensures that start is even, i.e., start on word boundary-- ***** buffer cache Э╩A  Ш JЪ╧cAЩAJЪЭ0Щ0JЪЭ0Щ0JШ Ъ╧k	Ш	JШJШJШJШ	ЧJШ ЪЬЮШ#JЪЮЬШJЪЮЬШЧJЪЮЬЮЬШJШ JЪЬЮЬШ.JЪЬЮЬШ%JЪЬЮЬЭ Ш9JЪЬЮЬЭ2ШKJЪЬЮЬЭ'Ш8JШ Ъ
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