135 lines
2.6 KiB
Plaintext
135 lines
2.6 KiB
Plaintext
(*
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Copyright 2018, 2020 Anton Krotov
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This file is part of fb2read.
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fb2read is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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fb2read is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with fb2read. If not, see <http://www.gnu.org/licenses/>.
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*)
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MODULE LISTS;
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TYPE
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LIST* = POINTER TO rLIST;
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ITEM* = POINTER TO rITEM;
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rITEM* = RECORD
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prev*, next*: ITEM;
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destroy*: PROCEDURE (VAR item: ITEM)
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END;
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rLIST* = RECORD
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first*, last*: ITEM
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END;
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PROCEDURE push* (list: LIST; item: ITEM);
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BEGIN
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ASSERT(list # NIL);
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ASSERT(item # NIL);
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IF list.first = NIL THEN
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list.first := item;
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list.last := item;
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item.prev := NIL;
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item.next := NIL
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ELSE
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ASSERT(list.last # NIL);
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item.prev := list.last;
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list.last.next := item;
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item.next := NIL;
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list.last := item
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END
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END push;
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PROCEDURE get* (list: LIST; n: INTEGER): ITEM;
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VAR
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cur: ITEM;
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BEGIN
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cur := list.first;
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WHILE (cur # NIL) & (n > 0) DO
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cur := cur.next;
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DEC(n)
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END
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RETURN cur
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END get;
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PROCEDURE idx* (list: LIST; item: ITEM): INTEGER;
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VAR
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cur: ITEM;
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n: INTEGER;
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BEGIN
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ASSERT(item # NIL);
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n := 0;
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cur := list.first;
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WHILE (cur # NIL) & (cur # item) DO
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cur := cur.next;
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INC(n)
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END;
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IF cur = NIL THEN
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n := -1
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END
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RETURN n
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END idx;
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PROCEDURE create* (list: LIST): LIST;
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BEGIN
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IF list = NIL THEN
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NEW(list)
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END;
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list.first := NIL;
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list.last := NIL
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RETURN list
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END create;
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PROCEDURE destroy* (VAR list: LIST);
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VAR
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item, next: ITEM;
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BEGIN
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IF list # NIL THEN
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item := list.first;
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WHILE item # NIL DO
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next := item.next;
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IF item.destroy # NIL THEN
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item.destroy(item)
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ELSE
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DISPOSE(item)
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END;
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item := next
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END;
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DISPOSE(list)
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END
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END destroy;
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END LISTS. |