1-- CXA5011.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, for both Float_Random and Discrete_Random packages,
28--      the following are true:
29--      1) two objects of type Generator are initialized to the same state.
30--      2) when the Function Reset is used to reset two generators
31--         to different time-dependent states, the resulting random values
32--         from each generator are different.
33--      3) when the Function Reset uses the same integer initiator
34--         to reset two generators to the same state, the resulting random
35--         values from each generator are identical.
36--      4) when the Function Reset uses different integer initiator
37--         values to reset two generators, the resulting random numbers are
38--         different.
39--
40-- TEST DESCRIPTION:
41--      This test evaluates components of the Ada.Numerics.Float_Random and
42--      Ada.Numerics.Discrete_Random packages.
43--      This test checks to see that objects of type Generator are initialized
44--      to the same state. In addition, the functionality of Function Reset is
45--      validated.
46--      For each of the objectives above, evaluation of the various generators
47--      is performed using each of the following techniques. When the states of
48--      two generators are to be compared, each state is saved, then
49--      transformed to a bounded-string variable.  The bounded-strings can
50--      then be compared for equality.  In this case, matching bounded-strings
51--      are evidence that the states of two generators are the same.
52--      In addition, two generators are compared by evaluating a series of
53--      random numbers they produce.  A matching series of random numbers
54--      implies that the generators were in the same state prior to producing
55--      the numbers.
56--
57--
58-- CHANGE HISTORY:
59--      20 Apr 95   SAIC    Initial prerelease version.
60--      07 Jul 95   SAIC    Incorporated reviewer comments/suggestions.
61--      22 Apr 96   SAIC    Incorporated reviewer comments for ACVC 2.1.
62--      17 Aug 96   SAIC    Deleted Subtest #2.
63--      09 Feb 01   RLB     Repaired to work on implementations with a 16-bit
64--                          Integer.
65
66--!
67
68with Ada.Exceptions;
69with Ada.Numerics.Float_Random;
70with Ada.Numerics.Discrete_Random;
71with Ada.Strings.Bounded;
72with ImpDef;
73with Report;
74
75procedure CXA5011 is
76begin
77
78   Report.Test ("CXA5011", "Check the effect of Function Reset on the " &
79                           "state of random number generators");
80
81   Test_Block:
82   declare
83
84      use Ada.Exceptions;
85      use Ada.Numerics;
86      use Ada.Strings.Bounded;
87
88      -- Declare an modular subtype, and use it to instantiate the discrete
89      -- random number generator generic package.
90
91      type    Discrete_Range   is mod 2**(Integer'Size-1);
92      package Discrete_Package is new Discrete_Random(Discrete_Range);
93
94      -- Declaration of random number generator objects.
95
96      Discrete_Generator_1,
97      Discrete_Generator_2  : Discrete_Package.Generator;
98      Float_Generator_1,
99      Float_Generator_2     : Float_Random.Generator;
100
101      -- Declaration of bounded string packages instantiated with the
102      -- value of Max_Image_Width constant from each random number generator
103      -- package, and bounded string variables used to hold the image of
104      -- random number generator states.
105
106      package Discrete_String_Pack is
107        new Generic_Bounded_Length(Discrete_Package.Max_Image_Width);
108
109      package Float_String_Pack is
110        new Generic_Bounded_Length(Float_Random.Max_Image_Width);
111
112      use Discrete_String_Pack, Float_String_Pack;
113
114      TC_Seed                  : Integer;
115      TC_Max_Loop_Count        : constant Natural := 1000;
116      Allowed_Matches          : constant Natural := 2;
117      --
118      -- In a sequence of TC_Max_Loop_Count random numbers that should
119      -- not match, some may match by chance.  Up to Allowed_Matches
120      -- numbers may match before the test is considered to fail.
121      --
122
123
124      procedure Check_Float_State (Gen_1, Gen_2 : Float_Random.Generator;
125                                   Sub_Test     : Integer;
126                                   States_Should_Match : Boolean) is
127
128         use type Float_Random.State;
129
130         State_1,
131         State_2         : Float_Random.State;
132
133         State_String_1,
134         State_String_2  : Float_String_Pack.Bounded_String :=
135                             Float_String_Pack.Null_Bounded_String;
136      begin
137
138         Float_Random.Save(Gen => Gen_1, To_State => State_1);
139         Float_Random.Save(Gen_2, State_2);
140
141         State_String_1 :=
142           Float_String_Pack.To_Bounded_String(Source =>
143             Float_Random.Image(Of_State => State_1));
144
145         State_String_2 :=
146           Float_String_Pack.To_Bounded_String(Float_Random.Image(State_2));
147
148         case States_Should_Match is
149            when True  =>
150               if State_1 /= State_2 then
151                  Report.Failed("Subtest #" & Integer'Image(Sub_Test)    &
152                                "   State values from Float generators " &
153                                "are not the same");
154               end if;
155               if State_String_1 /= State_String_2 then
156                  Report.Failed("Subtest #" & Integer'Image(Sub_Test)     &
157                                "   State strings from Float generators " &
158                                "are not the same");
159               end if;
160            when False =>
161               if State_1 = State_2 then
162                  Report.Failed("Subtest #" & Integer'Image(Sub_Test)    &
163                                "   State values from Float generators " &
164                                "are the same");
165               end if;
166               if State_String_1 = State_String_2 then
167                  Report.Failed("Subtest #" & Integer'Image(Sub_Test)     &
168                                "   State strings from Float generators " &
169                                "are the same");
170               end if;
171         end case;
172      end Check_Float_State;
173
174
175
176      procedure Check_Discrete_State (Gen_1,
177                                      Gen_2    : Discrete_Package.Generator;
178                                      Sub_Test : Integer;
179                                      States_Should_Match : Boolean) is
180
181         use type Discrete_Package.State;
182
183         State_1, State_2  : Discrete_Package.State;
184
185         State_String_1,
186         State_String_2    : Discrete_String_Pack.Bounded_String :=
187                               Discrete_String_Pack.Null_Bounded_String;
188      begin
189
190         Discrete_Package.Save(Gen      => Gen_1,
191                               To_State => State_1);
192         Discrete_Package.Save(Gen_2, To_State => State_2);
193
194         State_String_1 :=
195           Discrete_String_Pack.To_Bounded_String(Source =>
196             Discrete_Package.Image(Of_State => State_1));
197
198         State_String_2 :=
199           Discrete_String_Pack.To_Bounded_String(Source =>
200             Discrete_Package.Image(Of_State => State_2));
201
202         case States_Should_Match is
203            when True  =>
204               if State_1 /= State_2 then
205                  Report.Failed("Subtest #" & Integer'Image(Sub_Test) &
206                                "   State values from Discrete "      &
207                                "generators are not the same");
208               end if;
209               if State_String_1 /= State_String_2 then
210                  Report.Failed("Subtest #" & Integer'Image(Sub_Test) &
211                                "   State strings from Discrete "     &
212                                "generators are not the same");
213               end if;
214            when False =>
215               if State_1 = State_2 then
216                  Report.Failed("Subtest #" & Integer'Image(Sub_Test) &
217                                "   State values from Discrete "      &
218                                "generators are the same");
219               end if;
220               if State_String_1 = State_String_2 then
221                  Report.Failed("Subtest #" & Integer'Image(Sub_Test) &
222                                "   State strings from Discrete "     &
223                                "generators are the same");
224               end if;
225         end case;
226      end Check_Discrete_State;
227
228
229
230      procedure Check_Float_Values (Gen_1, Gen_2 : Float_Random.Generator;
231                                    Sub_Test     : Integer;
232                                    Values_Should_Match : Boolean) is
233         Matches         : Natural := 0;
234         Check_Failed    : Boolean := False;
235      begin
236         case Values_Should_Match is
237            when True  =>
238               for i in 1..TC_Max_Loop_Count loop
239                  if Float_Random.Random(Gen_1) /= Float_Random.Random(Gen_2)
240                  then
241                     Check_Failed := True;
242                     exit;
243                  end if;
244               end loop;
245               if Check_Failed then
246                  Report.Failed("Sub_Test # " & Integer'Image(Sub_Test)    &
247                                "   Random numbers from Float generators " &
248                                "Failed check");
249               end if;
250            when False =>
251               for i in 1..TC_Max_Loop_Count loop
252                  if Float_Random.Random(Gen_1) = Float_Random.Random(Gen_2)
253                  then
254                     Matches := Matches + 1;
255                  end if;
256               end loop;
257         end case;
258
259         if (Values_Should_Match and Check_Failed) or
260            (not Values_Should_Match and Matches > Allowed_Matches)
261         then
262            Report.Failed("Sub_Test # " & Integer'Image(Sub_Test)    &
263                          "   Random numbers from Float generators " &
264                          "Failed check");
265         end if;
266
267      end Check_Float_Values;
268
269
270
271      procedure Check_Discrete_Values (Gen_1,
272                                       Gen_2    : Discrete_Package.Generator;
273                                       Sub_Test : Integer;
274                                       Values_Should_Match : Boolean) is
275         Matches         : Natural := 0;
276         Check_Failed    : Boolean := False;
277      begin
278         case Values_Should_Match is
279            when True  =>
280               for i in 1..TC_Max_Loop_Count loop
281                  if Discrete_Package.Random(Gen_1) /=
282                     Discrete_Package.Random(Gen_2)
283                  then
284                     Check_Failed := True;
285                     exit;
286                  end if;
287               end loop;
288            when False =>
289               for i in 1..TC_Max_Loop_Count loop
290                  if Discrete_Package.Random(Gen_1) =
291                     Discrete_Package.Random(Gen_2)
292                  then
293                     Matches := Matches + 1;
294                  end if;
295               end loop;
296         end case;
297
298         if (Values_Should_Match and Check_Failed) or
299            (not Values_Should_Match and Matches > Allowed_Matches)
300         then
301            Report.Failed("Sub_Test # " & Integer'Image(Sub_Test)    &
302                          "   Random numbers from Discrete generators " &
303                          "Failed check");
304         end if;
305
306      end Check_Discrete_Values;
307
308
309
310   begin
311
312      Sub_Test_1:
313         -- Check that two objects of type Generator are initialized to the
314         -- same state.
315      begin
316
317         -- Since the discrete and float random generators are in the initial
318         -- state, using Procedure Save to save the states of the generator
319         -- objects, and transforming these states into strings using
320         -- Function Image, should yield identical strings.
321
322         Check_Discrete_State (Discrete_Generator_1,
323                               Discrete_Generator_2,
324                               Sub_Test => 1,
325                               States_Should_Match => True);
326
327         Check_Float_State (Float_Generator_1,
328                            Float_Generator_2,
329                            Sub_Test => 1,
330                            States_Should_Match => True);
331
332         -- Since the two random generator objects are in their initial
333         -- state, the values produced from each (upon calls to Random)
334         -- should be identical.
335
336         Check_Discrete_Values (Discrete_Generator_1,
337                                Discrete_Generator_2,
338                                Sub_Test => 1,
339                                Values_Should_Match => True);
340
341         Check_Float_Values (Float_Generator_1,
342                             Float_Generator_2,
343                             Sub_Test => 1,
344                             Values_Should_Match => True);
345
346      end Sub_Test_1;
347
348
349
350      Sub_Test_3:
351         -- Check that when the Function Reset uses the same integer
352         -- initiator to reset two generators to the same state, the
353         -- resulting random values and the state from each generator
354         -- are identical.
355      declare
356         use Discrete_Package, Float_Random;
357      begin
358
359         -- Reset the generators to the same states, using the version of
360         -- Function Reset with both generator parameter and initiator
361         -- specified.
362
363         TC_Seed := Integer(Random(Discrete_Generator_1));
364         Reset(Gen => Discrete_Generator_1, Initiator => TC_Seed);
365         Reset(Discrete_Generator_2, Initiator => TC_Seed);
366         Reset(Float_Generator_1, TC_Seed);
367         Reset(Float_Generator_2, TC_Seed);
368
369         -- Since the random generators have been reset to identical states,
370         -- bounded string images of these states should yield identical
371         -- strings.
372
373         Check_Discrete_State (Discrete_Generator_1,
374                               Discrete_Generator_2,
375                               Sub_Test => 3,
376                               States_Should_Match => True);
377
378         Check_Float_State (Float_Generator_1,
379                            Float_Generator_2,
380                            Sub_Test => 3,
381                            States_Should_Match => True);
382
383         -- Since the random generators have been reset to identical states,
384         -- the values produced from each (upon calls to Random) should
385         -- be identical.
386
387         Check_Discrete_Values (Discrete_Generator_1,
388                                Discrete_Generator_2,
389                                Sub_Test => 3,
390                                Values_Should_Match => True);
391
392         Check_Float_Values (Float_Generator_1,
393                             Float_Generator_2,
394                             Sub_Test => 3,
395                             Values_Should_Match => True);
396
397      end Sub_Test_3;
398
399
400
401      Sub_Test_4:
402         -- Check that when the Function Reset uses different integer
403         -- initiator values to reset two generators, the resulting random
404         -- numbers and states are different.
405      begin
406
407         -- Reset the generators to different states.
408
409         TC_Seed :=
410           Integer(Discrete_Package.Random(Discrete_Generator_1));
411
412         Discrete_Package.Reset(Gen       => Discrete_Generator_1,
413                                Initiator => TC_Seed);
414
415         -- Set the seed value to a different value for the second call
416         -- to Reset.
417         -- Note: A second call to Random could be made, as above, but that
418         --       would not ensure that the resulting seed value was
419         --       different from the first.
420
421         if TC_Seed /= Integer'Last then
422            TC_Seed := TC_Seed + 1;
423         else
424            TC_Seed := TC_Seed - 1;
425         end if;
426
427         Discrete_Package.Reset(Gen       => Discrete_Generator_2,
428                                Initiator => TC_Seed);
429
430         Float_Random.Reset(Float_Generator_1, 16#FF#);             -- 255
431         Float_Random.Reset(Float_Generator_2, 2#1110_0000#);       -- 224
432
433         -- Since the two float random generators are in different
434         -- states, the bounded string images depicting their states should
435         -- differ.
436
437         Check_Discrete_State (Discrete_Generator_1,
438                               Discrete_Generator_2,
439                               Sub_Test => 4,
440                               States_Should_Match => False);
441
442         Check_Float_State (Float_Generator_1,
443                            Float_Generator_2,
444                            Sub_Test => 4,
445                            States_Should_Match => False);
446
447         -- Since the two discrete random generator objects were reset
448         -- to different states, the values produced from each (upon calls
449         -- to Random) should differ.
450
451         Check_Discrete_Values (Discrete_Generator_1,
452                                Discrete_Generator_2,
453                                Sub_Test => 4,
454                                Values_Should_Match => False);
455
456         Check_Float_Values (Float_Generator_1,
457                             Float_Generator_2,
458                             Sub_Test => 4,
459                             Values_Should_Match => False);
460
461      end Sub_Test_4;
462
463   exception
464      when The_Error : others =>
465         Report.Failed ("The following exception was raised in the " &
466                        "Test_Block: " & Exception_Name(The_Error));
467   end Test_Block;
468
469   Report.Result;
470
471end CXA5011;
472