From: Philippe Pepos Petitclerc <ppeposp@gmail.com>
Date: Thu, 5 Nov 2015 19:22:28 +0000 (-0500)
Subject: Introduced xoring of String and a sequence of Bytes
X-Git-Tag: v0.8~106^2~2
X-Git-Url: http://nitlanguage.org

Introduced xoring of String and a sequence of Bytes

Signed-off-by: Philippe Pepos Petitclerc <ppeposp@gmail.com>
---

diff --git a/lib/crypto.nit b/lib/crypto.nit
index 011347d..73488d8 100644
--- a/lib/crypto.nit
+++ b/lib/crypto.nit
@@ -154,6 +154,32 @@ redef class String
 		end
 		return arr.to_s
 	end
+
+	# Returns `self` xored with `key`
+	#
+	# The shortest of the two is cycled through until the longest has been
+	# completely xored.
+	#
+	#     assert "goodmorning".xor(" ".to_bytes) == "GOODMORNING"
+	fun xor(key: SequenceRead[Byte]): String do
+		var xored = new Bytes.empty
+		var shortest: SequenceRead[Byte]
+		var longest: SequenceRead[Byte]
+
+		if key.length > self.length then
+			shortest = self.to_bytes
+			longest = key
+		else
+			shortest = key
+			longest = self.to_bytes
+		end
+
+		for i in longest.length.times do
+			xored.add(longest[i] ^ shortest[i % shortest.length])
+		end
+
+		return xored.to_s
+	end
 end
 
 redef class Int