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7483c888 AC |
1 | ------------------------------------------------------------------------------ |
2 | -- -- | |
3 | -- GNAT LIBRARY COMPONENTS -- | |
4 | -- -- | |
50878404 | 5 | -- A D A . C O N T A I N E R S . I N D E F I N I T E _ H O L D E R S -- |
7483c888 AC |
6 | -- -- |
7 | -- B o d y -- | |
8 | -- -- | |
4b490c1e | 9 | -- Copyright (C) 2012-2020, Free Software Foundation, Inc. -- |
7483c888 AC |
10 | -- -- |
11 | -- GNAT is free software; you can redistribute it and/or modify it under -- | |
12 | -- terms of the GNU General Public License as published by the Free Soft- -- | |
13 | -- ware Foundation; either version 3, or (at your option) any later ver- -- | |
14 | -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- | |
15 | -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- | |
16 | -- or FITNESS FOR A PARTICULAR PURPOSE. -- | |
17 | -- -- | |
18 | -- As a special exception under Section 7 of GPL version 3, you are granted -- | |
19 | -- additional permissions described in the GCC Runtime Library Exception, -- | |
20 | -- version 3.1, as published by the Free Software Foundation. -- | |
21 | -- -- | |
22 | -- You should have received a copy of the GNU General Public License and -- | |
23 | -- a copy of the GCC Runtime Library Exception along with this program; -- | |
24 | -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- | |
25 | -- <http://www.gnu.org/licenses/>. -- | |
26 | ------------------------------------------------------------------------------ | |
27 | ||
28 | with Ada.Unchecked_Deallocation; | |
29 | ||
30 | package body Ada.Containers.Indefinite_Holders is | |
31 | ||
32 | procedure Free is | |
33 | new Ada.Unchecked_Deallocation (Element_Type, Element_Access); | |
34 | ||
35 | --------- | |
36 | -- "=" -- | |
37 | --------- | |
38 | ||
39 | function "=" (Left, Right : Holder) return Boolean is | |
40 | begin | |
41 | if Left.Element = null and Right.Element = null then | |
42 | return True; | |
7483c888 AC |
43 | elsif Left.Element /= null and Right.Element /= null then |
44 | return Left.Element.all = Right.Element.all; | |
7483c888 AC |
45 | else |
46 | return False; | |
47 | end if; | |
48 | end "="; | |
49 | ||
50 | ------------ | |
51 | -- Adjust -- | |
52 | ------------ | |
53 | ||
54 | overriding procedure Adjust (Container : in out Holder) is | |
55 | begin | |
56 | if Container.Element /= null then | |
57 | Container.Element := new Element_Type'(Container.Element.all); | |
58 | end if; | |
59 | ||
60 | Container.Busy := 0; | |
61 | end Adjust; | |
62 | ||
aca670a0 AC |
63 | overriding procedure Adjust (Control : in out Reference_Control_Type) is |
64 | begin | |
65 | if Control.Container /= null then | |
129bbe43 RD |
66 | declare |
67 | B : Natural renames Control.Container.Busy; | |
68 | begin | |
69 | B := B + 1; | |
70 | end; | |
aca670a0 AC |
71 | end if; |
72 | end Adjust; | |
73 | ||
7483c888 AC |
74 | ------------ |
75 | -- Assign -- | |
76 | ------------ | |
77 | ||
78 | procedure Assign (Target : in out Holder; Source : Holder) is | |
79 | begin | |
80 | if Target.Busy /= 0 then | |
81 | raise Program_Error with "attempt to tamper with elements"; | |
82 | end if; | |
83 | ||
84 | if Target.Element /= Source.Element then | |
85 | Free (Target.Element); | |
86 | ||
87 | if Source.Element /= null then | |
88 | Target.Element := new Element_Type'(Source.Element.all); | |
89 | end if; | |
90 | end if; | |
91 | end Assign; | |
92 | ||
93 | ----------- | |
94 | -- Clear -- | |
95 | ----------- | |
96 | ||
97 | procedure Clear (Container : in out Holder) is | |
98 | begin | |
99 | if Container.Busy /= 0 then | |
100 | raise Program_Error with "attempt to tamper with elements"; | |
101 | end if; | |
102 | ||
103 | Free (Container.Element); | |
104 | end Clear; | |
105 | ||
aca670a0 AC |
106 | ------------------------ |
107 | -- Constant_Reference -- | |
108 | ------------------------ | |
109 | ||
110 | function Constant_Reference | |
111 | (Container : aliased Holder) return Constant_Reference_Type | |
112 | is | |
113 | Ref : constant Constant_Reference_Type := | |
129bbe43 | 114 | (Element => Container.Element.all'Access, |
aca670a0 | 115 | Control => (Controlled with Container'Unrestricted_Access)); |
129bbe43 | 116 | B : Natural renames Ref.Control.Container.Busy; |
aca670a0 | 117 | begin |
129bbe43 | 118 | B := B + 1; |
aca670a0 AC |
119 | return Ref; |
120 | end Constant_Reference; | |
121 | ||
7483c888 AC |
122 | ---------- |
123 | -- Copy -- | |
124 | ---------- | |
125 | ||
126 | function Copy (Source : Holder) return Holder is | |
127 | begin | |
128 | if Source.Element = null then | |
aca670a0 | 129 | return (Controlled with null, 0); |
7483c888 | 130 | else |
aca670a0 | 131 | return (Controlled with new Element_Type'(Source.Element.all), 0); |
7483c888 AC |
132 | end if; |
133 | end Copy; | |
134 | ||
135 | ------------- | |
136 | -- Element -- | |
137 | ------------- | |
138 | ||
139 | function Element (Container : Holder) return Element_Type is | |
140 | begin | |
141 | if Container.Element = null then | |
142 | raise Constraint_Error with "container is empty"; | |
7483c888 AC |
143 | else |
144 | return Container.Element.all; | |
145 | end if; | |
146 | end Element; | |
147 | ||
148 | -------------- | |
149 | -- Finalize -- | |
150 | -------------- | |
151 | ||
152 | overriding procedure Finalize (Container : in out Holder) is | |
153 | begin | |
154 | if Container.Busy /= 0 then | |
155 | raise Program_Error with "attempt to tamper with elements"; | |
156 | end if; | |
157 | ||
158 | Free (Container.Element); | |
159 | end Finalize; | |
160 | ||
129bbe43 | 161 | overriding procedure Finalize (Control : in out Reference_Control_Type) is |
aca670a0 AC |
162 | begin |
163 | if Control.Container /= null then | |
129bbe43 RD |
164 | declare |
165 | B : Natural renames Control.Container.Busy; | |
166 | begin | |
167 | B := B - 1; | |
168 | end; | |
aca670a0 | 169 | end if; |
129bbe43 | 170 | |
aca670a0 AC |
171 | Control.Container := null; |
172 | end Finalize; | |
173 | ||
7483c888 AC |
174 | -------------- |
175 | -- Is_Empty -- | |
176 | -------------- | |
177 | ||
178 | function Is_Empty (Container : Holder) return Boolean is | |
179 | begin | |
180 | return Container.Element = null; | |
181 | end Is_Empty; | |
182 | ||
183 | ---------- | |
184 | -- Move -- | |
185 | ---------- | |
186 | ||
187 | procedure Move (Target : in out Holder; Source : in out Holder) is | |
188 | begin | |
189 | if Target.Busy /= 0 then | |
190 | raise Program_Error with "attempt to tamper with elements"; | |
191 | end if; | |
192 | ||
193 | if Source.Busy /= 0 then | |
194 | raise Program_Error with "attempt to tamper with elements"; | |
195 | end if; | |
196 | ||
197 | if Target.Element /= Source.Element then | |
198 | Free (Target.Element); | |
199 | Target.Element := Source.Element; | |
200 | Source.Element := null; | |
201 | end if; | |
202 | end Move; | |
203 | ||
204 | ------------------- | |
205 | -- Query_Element -- | |
206 | ------------------- | |
207 | ||
208 | procedure Query_Element | |
209 | (Container : Holder; | |
210 | Process : not null access procedure (Element : Element_Type)) | |
211 | is | |
212 | B : Natural renames Container'Unrestricted_Access.Busy; | |
213 | ||
214 | begin | |
215 | if Container.Element = null then | |
216 | raise Constraint_Error with "container is empty"; | |
217 | end if; | |
218 | ||
219 | B := B + 1; | |
220 | ||
221 | begin | |
222 | Process (Container.Element.all); | |
7483c888 AC |
223 | exception |
224 | when others => | |
225 | B := B - 1; | |
7483c888 AC |
226 | raise; |
227 | end; | |
228 | ||
229 | B := B - 1; | |
230 | end Query_Element; | |
231 | ||
232 | ---------- | |
233 | -- Read -- | |
234 | ---------- | |
235 | ||
236 | procedure Read | |
237 | (Stream : not null access Ada.Streams.Root_Stream_Type'Class; | |
26e7e1a0 AC |
238 | Container : out Holder) |
239 | is | |
7483c888 AC |
240 | begin |
241 | Clear (Container); | |
242 | ||
243 | if not Boolean'Input (Stream) then | |
244 | Container.Element := new Element_Type'(Element_Type'Input (Stream)); | |
245 | end if; | |
246 | end Read; | |
247 | ||
aca670a0 AC |
248 | procedure Read |
249 | (Stream : not null access Root_Stream_Type'Class; | |
250 | Item : out Constant_Reference_Type) | |
251 | is | |
252 | begin | |
253 | raise Program_Error with "attempt to stream reference"; | |
254 | end Read; | |
255 | ||
256 | procedure Read | |
257 | (Stream : not null access Root_Stream_Type'Class; | |
258 | Item : out Reference_Type) | |
259 | is | |
260 | begin | |
261 | raise Program_Error with "attempt to stream reference"; | |
262 | end Read; | |
263 | ||
264 | --------------- | |
265 | -- Reference -- | |
266 | --------------- | |
267 | ||
268 | function Reference | |
269 | (Container : aliased in out Holder) return Reference_Type | |
270 | is | |
271 | Ref : constant Reference_Type := | |
129bbe43 | 272 | (Element => Container.Element.all'Access, |
aca670a0 AC |
273 | Control => (Controlled with Container'Unrestricted_Access)); |
274 | begin | |
129bbe43 | 275 | Container.Busy := Container.Busy + 1; |
aca670a0 AC |
276 | return Ref; |
277 | end Reference; | |
278 | ||
7483c888 AC |
279 | --------------------- |
280 | -- Replace_Element -- | |
281 | --------------------- | |
282 | ||
283 | procedure Replace_Element | |
26e7e1a0 AC |
284 | (Container : in out Holder; |
285 | New_Item : Element_Type) | |
286 | is | |
7483c888 AC |
287 | begin |
288 | if Container.Busy /= 0 then | |
289 | raise Program_Error with "attempt to tamper with elements"; | |
290 | end if; | |
291 | ||
50878404 AC |
292 | declare |
293 | X : Element_Access := Container.Element; | |
294 | ||
50878404 AC |
295 | -- Element allocator may need an accessibility check in case actual |
296 | -- type is class-wide or has access discriminants (RM 4.8(10.1) and | |
297 | -- AI12-0035). | |
29ba9f52 RD |
298 | |
299 | pragma Unsuppress (Accessibility_Check); | |
300 | ||
50878404 AC |
301 | begin |
302 | Container.Element := new Element_Type'(New_Item); | |
303 | Free (X); | |
304 | end; | |
7483c888 AC |
305 | end Replace_Element; |
306 | ||
307 | --------------- | |
308 | -- To_Holder -- | |
309 | --------------- | |
310 | ||
311 | function To_Holder (New_Item : Element_Type) return Holder is | |
129bbe43 | 312 | |
50878404 AC |
313 | -- The element allocator may need an accessibility check in the case the |
314 | -- actual type is class-wide or has access discriminants (RM 4.8(10.1) | |
315 | -- and AI12-0035). | |
29ba9f52 RD |
316 | |
317 | pragma Unsuppress (Accessibility_Check); | |
318 | ||
7483c888 | 319 | begin |
aca670a0 | 320 | return (Controlled with new Element_Type'(New_Item), 0); |
7483c888 AC |
321 | end To_Holder; |
322 | ||
323 | -------------------- | |
324 | -- Update_Element -- | |
325 | -------------------- | |
326 | ||
327 | procedure Update_Element | |
d6f824bf | 328 | (Container : in out Holder; |
7483c888 AC |
329 | Process : not null access procedure (Element : in out Element_Type)) |
330 | is | |
d6f824bf | 331 | B : Natural renames Container.Busy; |
7483c888 AC |
332 | |
333 | begin | |
334 | if Container.Element = null then | |
335 | raise Constraint_Error with "container is empty"; | |
336 | end if; | |
337 | ||
338 | B := B + 1; | |
339 | ||
340 | begin | |
341 | Process (Container.Element.all); | |
7483c888 AC |
342 | exception |
343 | when others => | |
344 | B := B - 1; | |
7483c888 AC |
345 | raise; |
346 | end; | |
347 | ||
348 | B := B - 1; | |
349 | end Update_Element; | |
350 | ||
351 | ----------- | |
352 | -- Write -- | |
353 | ----------- | |
354 | ||
355 | procedure Write | |
356 | (Stream : not null access Ada.Streams.Root_Stream_Type'Class; | |
26e7e1a0 AC |
357 | Container : Holder) |
358 | is | |
7483c888 AC |
359 | begin |
360 | Boolean'Output (Stream, Container.Element = null); | |
361 | ||
362 | if Container.Element /= null then | |
363 | Element_Type'Output (Stream, Container.Element.all); | |
364 | end if; | |
365 | end Write; | |
129bbe43 | 366 | |
aca670a0 AC |
367 | procedure Write |
368 | (Stream : not null access Root_Stream_Type'Class; | |
369 | Item : Reference_Type) | |
370 | is | |
371 | begin | |
372 | raise Program_Error with "attempt to stream reference"; | |
373 | end Write; | |
374 | ||
375 | procedure Write | |
376 | (Stream : not null access Root_Stream_Type'Class; | |
377 | Item : Constant_Reference_Type) | |
378 | is | |
379 | begin | |
380 | raise Program_Error with "attempt to stream reference"; | |
381 | end Write; | |
7483c888 AC |
382 | |
383 | end Ada.Containers.Indefinite_Holders; |