1-- CC70001.A
2--
3--                             Grant of Unlimited Rights
4--
5--     Under contracts F33600-87-D-0337, F33600-84-D-0280, MDA903-79-C-0687,
6--     F08630-91-C-0015, and DCA100-97-D-0025, the U.S. Government obtained
7--     unlimited rights in the software and documentation contained herein.
8--     Unlimited rights are defined in DFAR 252.227-7013(a)(19).  By making
9--     this public release, the Government intends to confer upon all
10--     recipients unlimited rights  equal to those held by the Government.
11--     These rights include rights to use, duplicate, release or disclose the
12--     released technical data and computer software in whole or in part, in
13--     any manner and for any purpose whatsoever, and to have or permit others
14--     to do so.
15--
16--                                    DISCLAIMER
17--
18--     ALL MATERIALS OR INFORMATION HEREIN RELEASED, MADE AVAILABLE OR
19--     DISCLOSED ARE AS IS.  THE GOVERNMENT MAKES NO EXPRESS OR IMPLIED
20--     WARRANTY AS TO ANY MATTER WHATSOEVER, INCLUDING THE CONDITIONS OF THE
21--     SOFTWARE, DOCUMENTATION OR OTHER INFORMATION RELEASED, MADE AVAILABLE
22--     OR DISCLOSED, OR THE OWNERSHIP, MERCHANTABILITY, OR FITNESS FOR A
23--     PARTICULAR PURPOSE OF SAID MATERIAL.
24--*
25--
26-- OBJECTIVE:
27--      Check that the template for a generic formal package may be a child
28--      package, and that a child instance which is an instance of the
29--      template may be passed as an actual to the formal package. Check that
30--      the visible part of the generic formal package includes the first list
31--      of basic declarative items of the package specification.
32--
33-- TEST DESCRIPTION:
34--      Declare a list abstraction in a generic package which manages lists of
35--      elements of any nonlimited type. Declare a generic child package of
36--      this package which defines additional list operations. Declare a
37--      generic subprogram which operates on lists of elements of discrete
38--      types. Provide the generic subprogram with three formal parameters:
39--      (1) a formal discrete type which represents a list element type, (2)
40--      a generic formal package with the parent list generic as template, and
41--      (3) a generic formal package with the child list generic as template.
42--      Use the formal discrete type as the generic formal actual part for the
43--      parent formal package. In the main program, declare an instance of
44--      parent, then declare an instance of the child which is itself a child
45--      the parent's instance. Pass these instances as actuals to the generic
46--      subprogram instance.
47--
48--
49-- CHANGE HISTORY:
50--      06 Dec 94   SAIC    ACVC 2.0
51--      05 Nov 95   SAIC    ACVC 2.0.1 fixes: Corrected syntax of formal
52--                          package declaration.
53--      27 Feb 97   PWB.CTA Added an elaboration pragma.
54--!
55
56generic
57   type Element_Type is private;  -- List elems may be of any nonlimited type.
58package CC70001_0 is              -- List abstraction.
59
60   type List_Type is limited private;
61
62
63   -- Return true if current element is last in the list.
64   function End_Of_List (L : List_Type) return Boolean;
65
66   -- Set "current" pointer to first list element.
67   procedure Reset (L : in out List_Type);
68
69private
70
71   type Node_Type;
72   type Node_Pointer is access Node_Type;
73
74   type Node_Type is record
75      Item : Element_Type;
76      Next : Node_Pointer;
77   end record;
78
79   type List_Type is record
80      First   : Node_Pointer;
81      Current : Node_Pointer;
82      Last    : Node_Pointer;
83   end record;
84
85end CC70001_0;
86
87
88     --==================================================================--
89
90
91package body CC70001_0 is
92
93   function End_Of_List (L : List_Type) return Boolean is
94   begin
95      return (L.Current = null);
96   end End_Of_List;
97
98
99   procedure Reset (L : in out List_Type) is
100   begin
101      L.Current := L.First;                 -- Set "current" pointer to first
102   end Reset;                               -- list element.
103
104end CC70001_0;
105
106
107     --==================================================================--
108
109
110-- Child must be generic since parent is generic. A formal parameter for
111-- "element type" can not be provided here, because then the type of list
112-- element assumed by these new operations would be different from that
113-- defined by the list type declared in the parent.
114
115generic
116package CC70001_0.CC70001_1 is    -- Additional list operations.
117
118   -- Read from current element and advance "current" pointer.
119   procedure Read_Element (L : in out List_Type; E : out Element_Type);
120
121   -- Write to current element and advance "current" pointer.
122   procedure Write_Element (L : in out List_Type; E : in Element_Type);
123
124   -- Add element to end of list.
125   procedure Add_Element (L : in out List_Type; E : in Element_Type);
126
127end CC70001_0.CC70001_1;
128
129
130     --==================================================================--
131
132
133package body CC70001_0.CC70001_1 is
134
135   procedure Read_Element (L : in out List_Type; E : out Element_Type) is
136   begin
137      -- ... Error-checking code omitted for brevity.
138      E         := L.Current.Item;       -- Retrieve current element.
139      L.Current := L.Current.Next;       -- Advance "current" pointer.
140   end Read_Element;
141
142
143   procedure Write_Element (L : in out List_Type; E : in Element_Type) is
144   begin
145      -- ... Error-checking code omitted for brevity.
146      L.Current.Item := E;               -- Write to current element.
147      L.Current      := L.Current.Next;  -- Advance "current" pointer.
148   end Write_Element;
149
150
151   procedure Add_Element (L : in out List_Type; E : in Element_Type) is
152      New_Node : Node_Pointer := new Node_Type'(E, null);
153   begin
154      if L.First = null then             -- No elements in list, so add new
155         L.First := New_Node;            -- element at beginning of list.
156      else
157         L.Last.Next := New_Node;        -- Add new element at end of list.
158      end if;
159      L.Last := New_Node;                -- Set last-in-list pointer.
160   end Add_Element;
161
162end CC70001_0.CC70001_1;
163
164
165     --==================================================================--
166
167
168with CC70001_0.CC70001_1;  -- Generic list abstraction + additional operations.
169generic
170
171   -- Import the list abstraction defined in CC70001_0, as well as the
172   -- additional operations defined in CC70001_0.CC70001_1. Declare a formal
173   -- discrete type. Restrict this generic procedure to operate only on lists
174   -- of discrete elements by passing the formal discrete type as an actual
175   -- parameter to the formal (parent) package.
176
177   type Elem_Type is (<>);                  -- Discrete types only.
178   with package List_Mgr is new CC70001_0 (Elem_Type);
179   with package List_Ops is new List_Mgr.CC70001_1 (<>);
180
181procedure CC70001_2 (L : in out List_Mgr.List_Type);
182
183
184     --==================================================================--
185
186
187procedure CC70001_2 (L : in out List_Mgr.List_Type) is
188begin
189   List_Mgr.Reset (L);
190   while not List_Mgr.End_Of_List (L) loop
191      List_Ops.Write_Element (L, Elem_Type'First);
192   end loop;
193end CC70001_2;
194
195
196     --==================================================================--
197
198
199package CC70001_3 is
200
201   type Points is range 0 .. 10;
202
203   -- ... Various other types used by the application.
204
205end CC70001_3;
206
207
208-- No body for CC70001_3;
209
210
211     --==================================================================--
212
213
214-- Declare instances of the generic list packages for the discrete type.
215-- In order to establish that the type passed as an actual to the parent
216-- generic (CC70001_0) is the one utilized by the child generic (CC70001_1),
217-- the instance of the child must itself be declared as a child of the
218-- instance of the parent. Since only library units may have or be children,
219-- both instances must be library units.
220
221with CC70001_0;            -- Generic list abstraction.
222with CC70001_3;            -- Package containing discrete type declaration.
223pragma Elaborate (CC70001_0);
224package CC70001_4 is new CC70001_0 (CC70001_3.Points);
225
226with CC70001_0.CC70001_1;  -- Generic extension to list abstraction.
227with CC70001_4;
228package CC70001_4.CC70001_5 is new CC70001_4.CC70001_1;
229
230
231     --==================================================================--
232
233
234with CC70001_2;            -- Generic "zeroing" op for lists of discrete types.
235with CC70001_3;            -- Types for application.
236with CC70001_4.CC70001_5;  -- Discrete list abstraction + additional ops.
237
238with Report;
239procedure CC70001 is
240
241   package Lists_Of_Scores renames CC70001_4;
242   package Score_Ops       renames CC70001_4.CC70001_5;
243
244   Scores : Lists_Of_Scores.List_Type;                -- List of points.
245
246   procedure Reset_All_Scores is new CC70001_2        -- Operation on lists of
247     (Elem_Type => CC70001_3.Points,                  -- points.
248      List_Mgr  => Lists_Of_Scores,
249      List_Ops  => Score_Ops);
250
251
252   -- Begin test code declarations: -----------------------
253
254   type TC_Score_Array is array (1 .. 3) of CC70001_3.Points;
255
256   TC_Initial_Values : constant TC_Score_Array := (2, 4, 6);
257   TC_Final_Values   : constant TC_Score_Array := (0, 0, 0);
258
259   TC_Correct_Initial_Values : Boolean := False;
260   TC_Correct_Final_Values   : Boolean := False;
261
262
263   procedure TC_Initialize_List (L : in out Lists_of_Scores.List_Type) is
264   begin                                  -- Initial list contains 3 scores
265      for I in TC_Score_Array'Range loop  -- with the values 2, 4, and 6.
266         Score_Ops.Add_Element (L, TC_Initial_Values(I));
267      end loop;
268   end TC_Initialize_List;
269
270
271   procedure TC_Verify_List (L        : in out Lists_of_Scores.List_Type;
272                             Expected : in     TC_Score_Array;
273                             OK       :    out Boolean) is
274      Actual : TC_Score_Array;
275   begin                                  -- Verify that all scores have been
276      Lists_of_Scores.Reset (L);          -- set to zero.
277      for I in TC_Score_Array'Range loop
278         Score_Ops.Read_Element (L, Actual(I));
279      end loop;
280      OK := (Actual = Expected);
281   end TC_Verify_List;
282
283   -- End test code declarations. -------------------------
284
285
286begin
287   Report.Test ("CC70001", "Check that the template for a generic formal "   &
288                "package may be a child package, and that a child instance " &
289                "which is an instance of the template may be passed as an "  &
290                "actual to the formal package. Check that the visible part " &
291                "of the generic formal package includes the first list of "  &
292                "basic declarative items of the package specification");
293
294   TC_Initialize_List (Scores);
295   TC_Verify_List (Scores, TC_Initial_Values, TC_Correct_Initial_Values);
296
297   if not TC_Correct_Initial_Values then
298      Report.Failed ("List contains incorrect initial values");
299   end if;
300
301   Reset_All_Scores (Scores);
302   TC_Verify_List (Scores, TC_Final_Values, TC_Correct_Final_Values);
303
304   if not TC_Correct_Final_Values then
305      Report.Failed ("List contains incorrect final values");
306   end if;
307
308   Report.Result;
309end CC70001;
310