1 files changed, 32 insertions, 0 deletions
diff --git a/src/utils/TextScorer.scala b/src/utils/TextScorer.scala
new file mode 100644
index 0000000..b02c250
--- /dev/null
+++ b/src/utils/TextScorer.scala
@@ -0,0 +1,32 @@
+package ixee.cryptopals.utils
+
+import ByteUtils._
+
+object TextScorer {
+  val controlChars: Seq[Byte] = Seq(
+    0x08, 0x09, 0x0a, 0x0b, 0x0d
+  ).map(_.toByte)
+
+  def isText(s: Iterable[Byte]): Boolean =
+    s.forall(_ @& 0x80.toByte == 0) &&
+    s.filter(_ < 0x20).forall(controlChars.contains _)
+
+  def score(s: Seq[Byte]): Double =
+    if (!isText(s))
+      -1  // not English text!
+    else
+      scoreBy(new String(s.toArray), Frequencies.cornell40kSample)
+      //score s
+
+  def scoreBy(s: String, fm: FrequencyMap): Double = {
+    val sfm = FrequencyMap.of(s)
+    fm diff sfm
+  }
+
+  def looksEnglish(s: String)(implicit fm: FrequencyMap): Boolean =
+    if (!isText(s.toCharArray.map(_.toByte)))
+      false
+    else
+      FrequencyMap.of(s).likelyFitting(fm)
+}
+