darvell · December 13, 2011 00:29 · Dec 13, 2011
diff --git a/gistfile1.py b/gistfile1.py
@@ -0,0 +1,36 @@
+def CorruptHuffman(filename,chance,maxlen):
+  with open(filename,"r+b") as f:
+    filesize = os.path.getsize(filename)
+    huffmanStart = 0
+    huffmanEnd = 0
+    found = 0
+
+    for i in range(0,filesize):
+      if found == 2:
+        break
+      f.seek(i)
+      if f.read(1) == '\xFF':
+        f.seek(i + 1)
+        if f.read(1) == '\xC4':
+          # Ok, we found a single huffman table, that's good!
+          # Let's go hunt for the end of it.
+          huffmanStart = i + 2
+          found += 1
+
+    found = False
+
+    for i in range(huffmanStart + 2,filesize):
+      if found == True:
+        break
+      f.seek(i)
+      if f.read(1) == '\xFF':
+        f.seek(i + 1)
+        if f.read(1) != '\x00':
+          huffmanEnd = i - 2
+          found = True
+
+    f.seek(random.randint(huffmanStart,huffmanEnd))
+    f.write(hex(random.randint(1,250)))
+    print 'Filesize: ' + str(filesize)
+    print 'Huffman Start: ' + str(huffmanStart)
+    print 'Huffman End: ' + str(huffmanEnd)