53 lines
1.8 KiB
Ada
53 lines
1.8 KiB
Ada
with Ada.Numerics.Float_Random; use Ada.Numerics.Float_Random;
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with Ada.Text_IO; use Ada.Text_IO;
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procedure Test_Dining_Philosophers is
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type Philosopher is (Aristotle, Kant, Spinoza, Marx, Russel);
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protected type Fork is
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entry Grab;
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procedure Put_Down;
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private
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Seized : Boolean := False;
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end Fork;
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protected body Fork is
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entry Grab when not Seized is
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begin
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Seized := True;
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end Grab;
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procedure Put_Down is
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begin
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Seized := False;
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end Put_Down;
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end Fork;
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Life_Span : constant := 20; -- In his life a philosopher eats 20 times
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task type Person (ID : Philosopher; First, Second : not null access Fork);
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task body Person is
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Dice : Generator;
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begin
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Reset (Dice);
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for Life_Cycle in 1..Life_Span loop
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Put_Line (Philosopher'Image (ID) & " is thinking");
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delay Duration (Random (Dice) * 0.100);
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Put_Line (Philosopher'Image (ID) & " is hungry");
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First.Grab;
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Second.Grab;
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Put_Line (Philosopher'Image (ID) & " is eating");
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delay Duration (Random (Dice) * 0.100);
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Second.Put_Down;
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First.Put_Down;
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end loop;
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Put_Line (Philosopher'Image (ID) & " is leaving");
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end Person;
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Forks : array (1..5) of aliased Fork; -- Forks for hungry philosophers
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-- Start philosophers
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Ph_1 : Person (Aristotle, Forks (1)'Access, Forks (2)'Access);
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Ph_2 : Person (Kant, Forks (2)'Access, Forks (3)'Access);
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Ph_3 : Person (Spinoza, Forks (3)'Access, Forks (4)'Access);
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Ph_4 : Person (Marx, Forks (4)'Access, Forks (5)'Access);
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Ph_5 : Person (Russel, Forks (1)'Access, Forks (5)'Access);
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begin
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null; -- Nothing to do in the main task, just sit and behold
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end Test_Dining_Philosophers;
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