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1eee94d3 GM |
1 | (* wlists.mod word lists module. |
2 | ||
83ffe9cd | 3 | Copyright (C) 2015-2023 Free Software Foundation, Inc. |
1eee94d3 GM |
4 | Contributed by Gaius Mulley <gaius@glam.ac.uk>. |
5 | ||
6 | This file is part of GNU Modula-2. | |
7 | ||
8 | GNU Modula-2 is free software; you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation; either version 3, or (at your option) | |
11 | any later version. | |
12 | ||
13 | GNU Modula-2 is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
19 | along with GNU Modula-2; see the file COPYING3. If not see | |
20 | <http://www.gnu.org/licenses/>. *) | |
21 | ||
22 | IMPLEMENTATION MODULE wlists ; | |
23 | ||
24 | ||
25 | FROM Storage IMPORT ALLOCATE, DEALLOCATE ; | |
26 | ||
27 | CONST | |
28 | maxNoOfElements = 5 ; | |
29 | ||
30 | TYPE | |
31 | wlist = POINTER TO RECORD | |
32 | noOfElements: CARDINAL ; | |
33 | elements : ARRAY [1..maxNoOfElements] OF WORD ; | |
34 | next : wlist ; | |
35 | END ; | |
36 | ||
37 | ||
38 | (* | |
39 | initList - creates a new wlist, l. | |
40 | *) | |
41 | ||
42 | PROCEDURE initList () : wlist ; | |
43 | VAR | |
44 | l: wlist ; | |
45 | BEGIN | |
46 | NEW (l) ; | |
47 | WITH l^ DO | |
48 | noOfElements := 0 ; | |
49 | next := NIL | |
50 | END ; | |
51 | RETURN l | |
52 | END initList ; | |
53 | ||
54 | ||
55 | (* | |
56 | killList - deletes the complete wlist, l. | |
57 | *) | |
58 | ||
59 | PROCEDURE killList (VAR l: wlist) ; | |
60 | BEGIN | |
61 | IF l#NIL | |
62 | THEN | |
63 | IF l^.next#NIL | |
64 | THEN | |
65 | killList (l^.next) | |
66 | END ; | |
67 | DISPOSE (l) | |
68 | END | |
69 | END killList ; | |
70 | ||
71 | ||
72 | (* | |
73 | replaceItemInList - replace the nth WORD in wlist, l. | |
74 | The first item in a wlists is at index, 1. | |
75 | If the index, n, is out of range nothing is changed. | |
76 | *) | |
77 | ||
78 | PROCEDURE replaceItemInList (l: wlist; n: CARDINAL; w: WORD) ; | |
79 | BEGIN | |
80 | WHILE l#NIL DO | |
81 | WITH l^ DO | |
82 | IF n<=noOfElements | |
83 | THEN | |
84 | elements[n] := w | |
85 | ELSE | |
86 | DEC (n, noOfElements) | |
87 | END | |
88 | END ; | |
89 | l := l^.next | |
90 | END | |
91 | END replaceItemInList ; | |
92 | ||
93 | ||
94 | (* | |
95 | putItemIntoList - places an WORD, c, into wlist, l. | |
96 | *) | |
97 | ||
98 | PROCEDURE putItemIntoList (l: wlist; c: WORD) ; | |
99 | BEGIN | |
100 | WITH l^ DO | |
101 | IF noOfElements<maxNoOfElements | |
102 | THEN | |
103 | INC (noOfElements) ; | |
104 | elements[noOfElements] := c | |
105 | ELSIF next#NIL | |
106 | THEN | |
107 | putItemIntoList (next, c) | |
108 | ELSE | |
109 | next := initList () ; | |
110 | putItemIntoList (next, c) | |
111 | END | |
112 | END | |
113 | END putItemIntoList ; | |
114 | ||
115 | ||
116 | (* | |
117 | getItemFromList - retrieves the nth WORD from wlist, l. | |
118 | *) | |
119 | ||
120 | PROCEDURE getItemFromList (l: wlist; n: CARDINAL) : WORD ; | |
121 | BEGIN | |
122 | WHILE l#NIL DO | |
123 | WITH l^ DO | |
124 | IF n<=noOfElements | |
125 | THEN | |
126 | RETURN elements[n] | |
127 | ELSE | |
128 | DEC (n, noOfElements) | |
129 | END | |
130 | END ; | |
131 | l := l^.next | |
132 | END ; | |
133 | RETURN 0 | |
134 | END getItemFromList ; | |
135 | ||
136 | ||
137 | (* | |
138 | getIndexOfList - returns the index for WORD, c, in wlist, l. | |
139 | If more than one WORD, c, exists the index | |
140 | for the first is returned. | |
141 | *) | |
142 | ||
143 | PROCEDURE getIndexOfList (l: wlist; c: WORD) : CARDINAL ; | |
144 | VAR | |
145 | i: CARDINAL ; | |
146 | BEGIN | |
147 | IF l=NIL | |
148 | THEN | |
149 | RETURN 0 | |
150 | ELSE | |
151 | WITH l^ DO | |
152 | i := 1 ; | |
153 | WHILE i<=noOfElements DO | |
154 | IF elements[i]=c | |
155 | THEN | |
156 | RETURN i | |
157 | ELSE | |
158 | INC(i) | |
159 | END | |
160 | END ; | |
161 | RETURN noOfElements + getIndexOfList (next, c) | |
162 | END | |
163 | END | |
164 | END getIndexOfList ; | |
165 | ||
166 | ||
167 | (* | |
168 | noOfItemsInList - returns the number of items in wlist, l. | |
169 | *) | |
170 | ||
171 | PROCEDURE noOfItemsInList (l: wlist) : CARDINAL ; | |
172 | VAR | |
173 | t: CARDINAL ; | |
174 | BEGIN | |
175 | IF l=NIL | |
176 | THEN | |
177 | RETURN 0 | |
178 | ELSE | |
179 | t := 0 ; | |
180 | REPEAT | |
181 | WITH l^ DO | |
182 | INC (t, noOfElements) | |
183 | END ; | |
184 | l := l^.next | |
185 | UNTIL l=NIL; | |
186 | RETURN t | |
187 | END | |
188 | END noOfItemsInList ; | |
189 | ||
190 | ||
191 | (* | |
192 | includeItemIntoList - adds an WORD, c, into a wlist providing | |
193 | the value does not already exist. | |
194 | *) | |
195 | ||
196 | PROCEDURE includeItemIntoList (l: wlist; c: WORD) ; | |
197 | BEGIN | |
198 | IF NOT isItemInList (l, c) | |
199 | THEN | |
200 | putItemIntoList (l, c) | |
201 | END | |
202 | END includeItemIntoList ; | |
203 | ||
204 | ||
205 | (* | |
206 | removeItem - remove an element at index, i, from the wlist data type. | |
207 | *) | |
208 | ||
209 | PROCEDURE removeItem (p, l: wlist; i: CARDINAL) ; | |
210 | BEGIN | |
211 | WITH l^ DO | |
212 | DEC (noOfElements) ; | |
213 | WHILE i<=noOfElements DO | |
214 | elements[i] := elements[i+1] ; | |
215 | INC (i) | |
216 | END ; | |
217 | IF (noOfElements=0) AND (p#NIL) | |
218 | THEN | |
219 | p^.next := l^.next ; | |
220 | DISPOSE (l) | |
221 | END | |
222 | END | |
223 | END removeItem ; | |
224 | ||
225 | ||
226 | (* | |
227 | removeItemFromList - removes a WORD, c, from a wlist. | |
228 | It assumes that this value only appears once. | |
229 | *) | |
230 | ||
231 | PROCEDURE removeItemFromList (l: wlist; c: WORD) ; | |
232 | VAR | |
233 | p : wlist ; | |
234 | i : CARDINAL ; | |
235 | found: BOOLEAN ; | |
236 | BEGIN | |
237 | IF l#NIL | |
238 | THEN | |
239 | found := FALSE ; | |
240 | p := NIL ; | |
241 | REPEAT | |
242 | WITH l^ DO | |
243 | i := 1 ; | |
244 | WHILE (i<=noOfElements) AND (elements[i]#c) DO | |
245 | INC (i) | |
246 | END ; | |
247 | END ; | |
248 | IF (i<=l^.noOfElements) AND (l^.elements[i]=c) | |
249 | THEN | |
250 | found := TRUE | |
251 | ELSE | |
252 | p := l ; | |
253 | l := l^.next | |
254 | END | |
255 | UNTIL (l=NIL) OR found ; | |
256 | IF found | |
257 | THEN | |
258 | removeItem (p, l, i) | |
259 | END | |
260 | END | |
261 | END removeItemFromList ; | |
262 | ||
263 | ||
264 | (* | |
265 | isItemInList - returns true if a WORD, c, was found in wlist, l. | |
266 | *) | |
267 | ||
268 | PROCEDURE isItemInList (l: wlist; c: WORD) : BOOLEAN ; | |
269 | VAR | |
270 | i: CARDINAL ; | |
271 | BEGIN | |
272 | REPEAT | |
273 | WITH l^ DO | |
274 | i := 1 ; | |
275 | WHILE i<=noOfElements DO | |
276 | IF elements[i]=c | |
277 | THEN | |
278 | RETURN TRUE | |
279 | ELSE | |
280 | INC (i) | |
281 | END | |
282 | END | |
283 | END ; | |
284 | l := l^.next | |
285 | UNTIL l=NIL ; | |
286 | RETURN FALSE | |
287 | END isItemInList ; | |
288 | ||
289 | ||
290 | (* | |
291 | foreachItemInListDo - calls procedure, P, foreach item in wlist, l. | |
292 | *) | |
293 | ||
294 | PROCEDURE foreachItemInListDo (l: wlist; p: performOperation) ; | |
295 | VAR | |
296 | i, n: CARDINAL ; | |
297 | BEGIN | |
298 | n := noOfItemsInList(l) ; | |
299 | i := 1 ; | |
300 | WHILE i<=n DO | |
301 | p (getItemFromList (l, i)) ; | |
302 | INC(i) | |
303 | END | |
304 | END foreachItemInListDo ; | |
305 | ||
306 | ||
307 | (* | |
308 | duplicateList - returns a duplicate wlist derived from, l. | |
309 | *) | |
310 | ||
311 | PROCEDURE duplicateList (l: wlist) : wlist ; | |
312 | VAR | |
313 | m : wlist ; | |
314 | n, i: CARDINAL ; | |
315 | BEGIN | |
316 | m := initList () ; | |
317 | n := noOfItemsInList (l) ; | |
318 | i := 1 ; | |
319 | WHILE i<=n DO | |
320 | putItemIntoList (m, getItemFromList (l, i)) ; | |
321 | INC (i) | |
322 | END ; | |
323 | RETURN m | |
324 | END duplicateList ; | |
325 | ||
326 | ||
327 | END wlists. |