1 files changed, 27 insertions, 5 deletions
diff --git a/src/utils/ByteUtils.scala b/src/utils/ByteUtils.scala
index 2c51917..18942c0 100644
--- a/src/utils/ByteUtils.scala
+++ b/src/utils/ByteUtils.scala
@@ -1,6 +1,7 @@
 package ixee.cryptopals.utils
 
 import FunctionUtils.tup
+import ConversionUtils._
 
 object ByteUtils {
   trait SizedNumeric[T] {
@@ -9,8 +10,8 @@ object ByteUtils {
     def bitSize: Int
     def fromLong(l: Long): T
     def toLong(l: T): Long
-    def buildFrom[U : SizedNumeric](from: U): T = fromLong(from.toLong)
-    def truncate[U : SizedNumeric](from: U): T = buildFrom(from)
+    def buildFrom[U : SizedNumeric : BitOps](from: U): T = fromLong(from.toLong)
+    def truncate[U : SizedNumeric : BitOps](from: U): T = buildFrom(from)
     override def toString = s"SizedNumeric[${manifest}]"
   }
 
@@ -21,6 +22,7 @@ object ByteUtils {
     def @&(a: T, b: T): T
     def @^(a: T, b: T): T
     def @+(a: T, b: T): T
+    def @-(a: T, b: T): T
   }
 
   implicit val byteOps: BitOps[Byte] = new BitOps[Byte] {
@@ -30,6 +32,7 @@ object ByteUtils {
     def @&(a: Byte, b: Byte): Byte = (a & b).toByte
     def @^(a: Byte, b: Byte): Byte = (a ^ b).toByte
     def @+(a: Byte, b: Byte): Byte = (a + b).toByte
+    def @-(a: Byte, b: Byte): Byte = (a - b).toByte
   }
 
   implicit val intOps: BitOps[Int] = new BitOps[Int] {
@@ -39,6 +42,7 @@ object ByteUtils {
     def @&(a: Int, b: Int): Int = a & b
     def @^(a: Int, b: Int): Int = a ^ b
     def @+(a: Int, b: Int): Int = a + b
+    def @-(a: Int, b: Int): Int = a - b
   }
 
   implicit class WithBitOpts[T : BitOps](x: T) {
@@ -48,9 +52,10 @@ object ByteUtils {
     def @&(b: T): T = implicitly[BitOps[T]].@&(x, b)
     def @^(b: T): T = implicitly[BitOps[T]].@^(x, b)
     def @+(b: T): T = implicitly[BitOps[T]].@+(x, b)
+    def @-(b: T): T = implicitly[BitOps[T]].@-(x, b)
   }
 
-  implicit class SizedWithByteInfo[T : SizedNumeric](x: T) {
+  implicit class SizedWithByteInfo[T : SizedNumeric : BitOps](x: T) {
     def byteSize = implicitly[SizedNumeric[T]].byteSize
     def octetSize = byteSize * 2
     def bitSize = implicitly[SizedNumeric[T]].bitSize
@@ -65,6 +70,17 @@ object ByteUtils {
       uSize.buildFrom(x)
     }
     def hex: String = s"%0${octetSize}x" format x
+    def bitsSet: Int = {
+      var bits = 0
+      var num = x
+
+      while (num.toLong > 0) {
+        bits = bits + 1
+        num = num @& (num @- 1.truncatedTo[T])
+      }
+
+      bits
+    }
     def truncatedTo[U : SizedNumeric]: U = {
       implicitly[SizedNumeric[U]].truncate(x)
     }
@@ -82,8 +98,14 @@ object ByteUtils {
   implicit val shortized = sizedNumeric(2) { x: Long => x.toShort } { _.toLong }
   implicit val byteSized = sizedNumeric(1) { x: Long => x.toByte } { _.toLong }
 
-  implicit class SeqByteOps(seq: Seq[Byte]) {
-    def xor(other: Seq[Byte]): Seq[Byte] =
+  implicit class SeqByteOps[T : SizedNumeric : BitOps](seq: Seq[T]) {
+    def xor(other: Seq[T]): Seq[T] =
       seq.zip(other).map(tup(_ @^ _))
   }
+
+  def hammingDistance(a: String, b: String): Int =
+    hammingDistance(a.asBytes, b.asBytes)
+
+  def hammingDistance[T : BitOps : SizedNumeric](a: Seq[T], b: Seq[T]): Int =
+    (a xor b).map(_.bitsSet).reduce(_ @+ _)
 }