encoder and compare

main.py

@@ -26,13 +26,79 @@ def Q_statistik():
     return freq, prob, info_content, entropy
 
 
+def fano_encoder(probabilities):
+    # Key = probability im Dictionary
+    sorted_probs = sorted(probabilities.items(), key=lambda x: x[1], reverse=True)
+
+    def fano_recursive(symbols):
+        if len(symbols) == 1:  # Keine neuen Teilmengen möglich
+            return {symbols[0][0]: ""}
+
+        total = sum([symbol[1] for symbol in symbols])
+        acc = 0
+        split_index = 0
+        for i in range(len(symbols)):
+            acc += symbols[i][1]
+            if acc >= total / 2:
+                split_index = i
+                break
+
+        left_symbols = symbols[:split_index + 1]
+        right_symbols = symbols[split_index + 1:]
+
+        left_codes = fano_recursive(left_symbols)
+        right_codes = fano_recursive(right_symbols)
+
+        for key in left_codes:
+            left_codes[key] = '0' + left_codes[key]
+        for key in right_codes:
+            right_codes[key] = '1' + right_codes[key]
+
+        left_codes.update(right_codes)
+        return left_codes
+
+    return fano_recursive(sorted_probs)
+
+
+def Q_Fanoencoder(input_path='Text.txt', output_path='EncodedText.txt'):
+    _, probabilities, _, _ = Q_statistik()
+    fano_codes = fano_encoder(probabilities)
+
+    with open(input_path, 'r', encoding='utf-8') as file:
+        text = file.read()
+
+    encoded_text = ''.join([fano_codes[char] for char in text])
+
+    with open(output_path, 'w', encoding='utf-8') as file:
+        file.write(encoded_text)
+
+    return text, encoded_text, fano_codes
+
+
+def calculate_compression_rate(original_text, encoded_text, fano_codes):
+    original_length_bits = len(original_text) * 8
+    encoded_length_bits = len(encoded_text)
+    code_table_bits = sum([len(code) for code in fano_codes.values()]) * 8 + len(fano_codes) * 8
+    total_encoded_bits = encoded_length_bits + code_table_bits
+    compression_rate = (original_length_bits - total_encoded_bits) / original_length_bits * 100
+
+    return original_length_bits, total_encoded_bits, compression_rate
+
+
 def main():
     frequencies, probabilities, information_content, entropy = Q_statistik()
     print("Häufigkeiten:", frequencies)
     print("Wahrscheinlichkeiten:", probabilities)
     print("Informationsgehalt:", information_content)
     print("Entropie:", entropy)
+    original_text, encoded_text, fano_codes = Q_Fanoencoder()
+    original_length_bits, total_encoded_bits, compression_rate = (
+        calculate_compression_rate(original_text, encoded_text, fano_codes)
+    )
+    print(f"Originale Länge in Bits: {original_length_bits}")
+    print(f"Gesamte codierte Länge in Bits (inkl. Codetabelle): {total_encoded_bits}")
+    print(f"Kompressionsrate: {compression_rate:.2f}%")
 
 
 if __name__ == '__main__':
-        main()
+    main()