From f684dfa0044c016b39a8527627cd72604a27efea Mon Sep 17 00:00:00 2001
From: Conrad <grosserconrad@gmail.com>
Date: Mon, 15 Jul 2019 21:27:52 +0200
Subject: [PATCH] Added the calc_entro.py calculator

---
 calc_entro.py | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 calc_entro.py

diff --git a/calc_entro.py b/calc_entro.py
new file mode 100644
index 0000000..ac70f33
--- /dev/null
+++ b/calc_entro.py
@@ -0,0 +1,87 @@
+'''
+    calc_entro.py calculates the entropy of a given string or file
+
+    This uses the negative sum of the log (to the base of 2) of the probability
+    times the probability of a char to occur in a certain string as the entropy.
+'''
+
+import math
+import argparse
+
+
+# Calculates the entropy of a given string (as described in the docstring)
+def calcEntropy(string):
+    alphabet, alphabet_size, entropy = {}, 0, 0
+
+    for char in string:
+        if char in alphabet:
+            alphabet[char] += 1
+        else:
+            alphabet[char] = 1
+        alphabet_size += 1
+
+    for char in alphabet:
+        alphabet[char] = alphabet[char] / alphabet_size
+        entropy += alphabet[char] * math.log(alphabet[char], 2)
+
+    return -entropy, alphabet
+
+
+# Outputs a given entropy including the original text and the alphabet with probabilities
+def printEntropy(original, entropy, alphabet, simple):
+    print('---')
+    if simple == False:
+        print('Content: ' + original)
+        print('Probabilities: ' + str(alphabet))
+    print('Entropy: ' + str(entropy))
+    print('---')
+
+
+# Reads a file by a given path
+def getFile(path):
+    f = open(path, 'r')
+    content = f.read().replace('\n', ' ')
+    f.close()
+    return content.strip()
+
+
+# List of the arguments one can use to influence the behavior of the program
+parser = argparse.ArgumentParser(description='Calculate the information entropy of some strings.')
+
+# INPUT ARGUMENTS
+parser.add_argument('strings', nargs='*', default='', type=str, help='Strings to calculate the entropy of.')
+parser.add_argument('--files', nargs='*', type=str, default='', help='Provide file path(s) to calculate the entropy of.')
+
+# OUTPUT OPTIONS
+parser.add_argument('--simple', nargs='?', type=bool, default=False, help='Determines the explicitness of the output. (True = only entropy shown)')
+
+# CONVERT OPTIONS
+parser.add_argument('--lower', nargs='?', type=bool, default=False, help='Converts given strings or textfiles to lowercase before calculating.')
+parser.add_argument('--upper', nargs='?', type=bool, default=False, help='Converts given strings or textfiles to uppercase before calculating.')
+parser.add_argument('--squash', nargs='?', type=bool, default=False, help='Removes all whitespaces before calculating.')
+args = parser.parse_args()
+
+# Prepares the queue of different strings
+queue = []
+
+# Add all the provided strings to the list
+for string in args.strings:
+    queue.append(string)
+
+# Add all the provided files to the list
+for file in args.files:
+    string = getFile(file)
+    queue.append(string)
+
+# Interates over the collected strings and prints the entropies
+for string in queue:
+    if args.lower != False:
+        string = string.lower()
+    elif args.upper != False:
+        string = string.upper()
+
+    if args.squash != False:
+        string = string.replace(" ", "")
+
+    a, b = calcEntropy(string)
+    printEntropy(string, a, b, args.simple)