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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 . |
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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. |