A-M baby

Task/Huffman-coding/Ada/huffman-coding-3.ada

@@ -0,0 +1,49 @@
+with Ada.Text_IO;
+with Huffman;
+procedure Main is
+   package Char_Natural_Huffman_Tree is new Huffman
+     (Symbol_Type => Character,
+      Put => Ada.Text_IO.Put,
+      Symbol_Sequence => String,
+      Frequency_Type => Natural);
+   Tree         : Char_Natural_Huffman_Tree.Huffman_Tree;
+   Frequencies  : Char_Natural_Huffman_Tree.Frequency_Maps.Map;
+   Input_String : constant String :=
+     "this is an example for huffman encoding";
+begin
+   -- build frequency map
+   for I in Input_String'Range loop
+      declare
+         use Char_Natural_Huffman_Tree.Frequency_Maps;
+         Position : constant Cursor := Frequencies.Find (Input_String (I));
+      begin
+         if Position = No_Element then
+            Frequencies.Insert (Key => Input_String (I), New_Item => 1);
+         else
+            Frequencies.Replace_Element
+              (Position => Position,
+               New_Item => Element (Position) + 1);
+         end if;
+      end;
+   end loop;
+
+   -- create huffman tree
+   Char_Natural_Huffman_Tree.Create_Tree
+     (Tree        => Tree,
+      Frequencies => Frequencies);
+
+   -- dump encodings
+   Char_Natural_Huffman_Tree.Dump_Encoding (Tree => Tree);
+
+   -- encode example string
+   declare
+      Code : constant Char_Natural_Huffman_Tree.Bit_Sequence :=
+        Char_Natural_Huffman_Tree.Encode
+          (Tree    => Tree,
+           Symbols => Input_String);
+   begin
+      Char_Natural_Huffman_Tree.Put (Code);
+      Ada.Text_IO.Put_Line
+        (Char_Natural_Huffman_Tree.Decode (Tree => Tree, Code => Code));
+   end;
+end Main;