Brainfuck interpreter in Ada

1 files changed, 124 insertions, 0 deletions

diff --git a/src/Brainfuck/brainfuck.adb b/src/Brainfuck/brainfuck.adb
new file mode 100644
index 0000000..26de72c
--- /dev/null
+++ b/src/Brainfuck/brainfuck.adb
@@ -0,0 +1,124 @@
+
+
+with Ada.Text_IO;
+with Ada.Direct_IO;
+with Ada.Command_Line;
+
+
+procedure Brainfuck is
+
+
+    package CL renames Ada.Command_Line;
+    package Text_IO renames Ada.Text_IO;
+
+
+    package Direct_IO is new Ada.Direct_IO(Character);
+    use type Direct_IO.Count;
+
+
+    type Cell is mod 256;
+    type Tape_Position is mod 5000;
+    type Program_Tape is array (Tape_Position'Range) of Cell;
+    pragma Pack (Program_Tape);
+
+
+    Input_File : Direct_IO.File_Type;
+    File_Position : Direct_IO.Positive_Count;
+    Counter : Integer;
+    Current_Char : Character;
+    Tape : Program_Tape;
+    Current_Cell : Tape_Position;
+
+
+begin
+
+
+    if CL.Argument_Count /= 1 then
+        Text_IO.Put_Line(Text_IO.Standard_Error, "Please supply the filename of a brainfuck program");
+        CL.Set_Exit_Status(CL.Failure);
+        return;
+    end if;
+
+
+    begin
+        Direct_IO.Open( File => Input_File,
+        	            Mode => Direct_IO.In_File,
+        	            Name => CL.Argument(1) );
+    exception
+        when others =>
+            Text_IO.Put_Line(Text_IO.Standard_Error, "Can not open the file '" & CL.Argument(1) & "'. Does it exist?");
+            CL.Set_Exit_Status(CL.Failure);
+            return;
+    end;
+
+
+    Tape := (others => 0);
+    Current_Cell := Tape_Position'First;
+
+    while not Direct_IO.End_Of_File(Input_File) loop
+        Direct_IO.Read(Input_File, Current_Char);
+        
+        case Current_Char is
+
+            when '>' =>
+                Current_Cell := Current_Cell + 1;
+
+            when '<' =>
+                Current_Cell := Current_Cell - 1;
+            
+            when '+' =>
+                Tape(Current_Cell) := Tape(Current_Cell) + 1;
+            
+            when '-' =>
+                Tape(Current_Cell) := Tape(Current_Cell) - 1;
+            
+            when '.' =>
+                Text_IO.Put(Character'Val(Tape(Current_Cell)));
+            
+            when ',' =>
+                Text_IO.Get(Current_Char);
+                Tape(Current_Cell) := Character'Pos(Current_Char);
+
+            when '[' =>
+                if Tape(Current_Cell) = 0 then
+                    Counter := 1;
+                    while Counter > 0 and not Direct_IO.End_Of_File(Input_File) loop
+                        Direct_IO.Read(Input_File, Current_Char);
+                        if Current_Char = '[' then
+                            Counter := Counter + 1;
+                        elsif Current_Char = ']' then
+                            Counter := Counter - 1;
+                        end if;
+                    end loop;
+                end if;
+
+            when ']' =>
+                if Tape(Current_Cell) /= 0 then
+                    Counter := 0;
+                    File_Position := Direct_IO.Index(Input_File) - 1;
+                    loop
+                        Direct_IO.Set_Index(Input_File, File_Position);
+                        Direct_IO.Read(Input_File, Current_Char);
+                        if Current_Char = ']' then
+                            Counter := Counter + 1;
+                        elsif Current_Char = '[' then
+                            Counter := Counter - 1;
+                        end if;
+                        File_Position := File_Position - 1;
+                        exit when Counter < 1;
+                    end loop;
+                end if;
+
+            when others =>
+                null;
+
+        end case;
+
+    end loop;
+
+
+    Direct_IO.Close(Input_File);
+
+
+end Brainfuck;
+