Moving into subdirectory 'tools' + renamed

tools/text2base64.py

@@ -0,0 +1,71 @@
+#!/usr/bin/env python
+#Takes a string as an argument and returns 3 base64 encoded string partials.
+#One of these strings is guaranteed to be present in the base64 content if
+#the original plain-text code contained the (case-sensitive) input string.
+
+#Due to the 8 bit to 6 bit encoding conversion involved in base64 encoding,
+#the edges don't always align nicely, so trimming is required as the first
+#and last characters may be different depending on the immediate context.
+
+from base64 import b64encode
+import sys
+
+def main(input):
+        L_offset = 0
+        R_offset = 3 - ((len(input) + L_offset) % 3)
+        if (R_offset == 3):
+                R_offset = 0
+
+        e1, e2, e3 = encode(input)
+
+        e1 = trim(e1, L_offset, R_offset)
+
+        L_offset += 1
+        R_offset = 3 - ((len(input) + L_offset) % 3)
+        if (R_offset == 3):
+                R_offset = 0
+
+        e2 = trim(e2, L_offset, R_offset)
+
+        L_offset += 1
+        R_offset = 3 - ((len(input) + L_offset) % 3)
+        if (R_offset == 3):
+                R_offset = 0
+
+        e3 = trim(e3, L_offset, R_offset)
+
+        print(e1)
+        print(e2)
+        print(e3)
+
+def offset_2_chars(offset):
+        if (offset == 0):
+                return 0
+        elif (offset == 1):
+                return 2
+        else:
+                return 3
+
+def trim(input, L_offset, R_offset):
+        input = trimL(input, L_offset)
+        input = trimR(input, R_offset)
+        return input
+
+def trimL(input, offset):
+        left_cut = offset_2_chars(offset)
+        return input[left_cut:]
+
+def trimR(input, offset):
+        if (offset == 0):
+                return input
+        right_cut = offset_2_chars(offset)
+        return input[:-right_cut]
+
+def encode(input):
+        e1 = b64encode(input)
+        e2 = b64encode('0' + input)
+        e3 = b64encode('00' + input)
+        return e1, e2, e3
+
+if __name__ == '__main__':
+        main(sys.argv[1])