InterruptDB + AffineSolver

HeuristicLib.py

@@ -0,0 +1,68 @@
+#!/usr/bin/env python3
+import re
+from RuneText import RuneText
+from NGrams import NGrams
+
+
+def normalized_probability(int_prob):
+    total = sum(int_prob)
+    return [x / total for x in int_prob]  # math.log(x / total, 10)
+
+
+RUNES = 'ᚠᚢᚦᚩᚱᚳᚷᚹᚻᚾᛁᛄᛇᛈᛉᛋᛏᛒᛖᛗᛚᛝᛟᛞᚪᚫᚣᛡᛠ'
+re_norune = re.compile('[^' + RUNES + ']')
+PROB_INT = [0] * 29
+for k, v in NGrams.load().items():
+    PROB_INT[RUNES.index(k)] = v
+PROB_NORM = normalized_probability(PROB_INT)
+K_r = 1 / 29   # 0.034482758620689655
+K_p = sum(x ** 2 for x in PROB_INT)  # 0.06116195419412538
+
+
+#########################################
+#  Probability  :  Count runes and do simple frequency analysis
+#########################################
+
+class Probability(object):
+    def __init__(self, numstream):
+        self.prob = [0] * 29
+        for r in numstream:
+            self.prob[r] += 1
+        self.N = len(numstream)
+
+    def IC(self):
+        X = sum(x * (x - 1) for x in self.prob)
+        return X / ((self.N * (self.N - 1)) / 29)
+
+    def friedman(self):
+        return (K_p - K_r) / (self.IC() - K_r)
+
+    def similarity(self):
+        probs = normalized_probability(self.prob)
+        return sum((x - y) ** 2 for x, y in zip(PROB_NORM, probs))
+
+    @staticmethod
+    def IC_w_keylen(nums, keylen):
+        val = sum(Probability(nums[x::keylen]).IC() for x in range(keylen))
+        return val / keylen
+
+
+#########################################
+#  load page and convert to indices for faster access
+#########################################
+
+def load_indices(fname, interrupt, maxinterrupt=None, minlen=None, limit=None):
+    with open(fname, 'r') as f:
+        data = RuneText(re_norune.sub('', f.read()))['index'][:limit]
+    if maxinterrupt is not None:
+        # incl. everything up to but not including next interrupt
+        # e.g., maxinterrupt = 0 will return text until first interrupt
+        for i, x in enumerate(data):
+            if x != interrupt:
+                continue
+            if maxinterrupt == 0:
+                if minlen and i < minlen:
+                    continue
+                return data[:i]
+            maxinterrupt -= 1
+    return data