util-core: Enable ByteReader to Read Unsigned Longs

Problem

readUnsignedLongBE and readUnsignedLongLE are missing in ByteReader
implementation.

Solution

Added readUnsignedLongBE and readUnsignedLongLE to ByteReader and
implemented in ByteReaderImpl.

Signed-off-by: Ryan O'Neill <ryano@twitter.com>

RB_ID=917289

finagle-netty4/src/main/scala/com/twitter/finagle/netty4/AbstractByteBufByteReader.scala

@@ -109,6 +109,42 @@ private[netty4] abstract class AbstractByteBufByteReader(bb: ByteBuf) extends By
     bb.readLongLE()
   }
 
+  final def readUnsignedLongBE(): BigInt = {
+    checkRemaining(8)
+
+    // 9 (8+1) so sign bit is always positive
+    val bytes: Array[Byte] = new Array[Byte](9)
+    bytes(0) = 0
+    bytes(1) = bb.readByte()
+    bytes(2) = bb.readByte()
+    bytes(3) = bb.readByte()
+    bytes(4) = bb.readByte()
+    bytes(5) = bb.readByte()
+    bytes(6) = bb.readByte()
+    bytes(7) = bb.readByte()
+    bytes(8) = bb.readByte()
+
+    BigInt(bytes)
+  }
+
+  final def readUnsignedLongLE(): BigInt = {
+    checkRemaining(8)
+
+    // 9 (8+1) so sign bit is always positive
+    val bytes: Array[Byte] = new Array[Byte](9)
+    bytes(8) = bb.readByte()
+    bytes(7) = bb.readByte()
+    bytes(6) = bb.readByte()
+    bytes(5) = bb.readByte()
+    bytes(4) = bb.readByte()
+    bytes(3) = bb.readByte()
+    bytes(2) = bb.readByte()
+    bytes(1) = bb.readByte()
+    bytes(0) = 0
+
+    BigInt(bytes)
+  }
+
   final def readFloatBE(): Float = {
     JFloat.intBitsToFloat(readIntBE())
   }

finagle-netty4/src/test/scala/com/twitter/finagle/netty4/AbstractByteBufByteReaderTest.scala

@@ -4,6 +4,7 @@ import com.twitter.io.ByteReader.UnderflowException
 import com.twitter.io.{Buf, ByteReader}
 import io.netty.buffer.{ByteBuf, UnpooledByteBufAllocator}
 import java.lang.{Double => JDouble, Float => JFloat}
+import org.scalacheck.Gen
 import org.scalatest.FunSuite
 import org.scalatest.prop.GeneratorDrivenPropertyChecks
 
@@ -184,6 +185,38 @@ abstract class AbstractByteBufByteReaderTest extends FunSuite with GeneratorDriv
     assert(br.readUnsignedIntLE() == (i & 0xffffffffl))
   })
 
+  val uInt64s: Gen[BigInt] = Gen.chooseNum(Long.MinValue, Long.MaxValue)
+    .map(x => BigInt(x) + BigInt(2).pow(63))
+
+  test("readUnsignedLongBE") (forAll(uInt64s) { bi: BigInt =>
+    val br = readerWith(
+      ((bi >> 56) & 0xff).toByte,
+      ((bi >> 48) & 0xff).toByte,
+      ((bi >> 40) & 0xff).toByte,
+      ((bi >> 32) & 0xff).toByte,
+      ((bi >> 24) & 0xff).toByte,
+      ((bi >> 16) & 0xff).toByte,
+      ((bi >>  8) & 0xff).toByte,
+      ((bi      ) & 0xff).toByte)
+    assert(br.readUnsignedLongBE() == bi)
+    val exc = intercept[UnderflowException] { br.readByte() }
+  })
+
+  test("readUnsignedLongLE") (forAll(uInt64s) { bi1: BigInt =>
+    val bi = bi1.abs
+    val br = readerWith(
+      ((bi      ) & 0xff).toByte,
+      ((bi >>  8) & 0xff).toByte,
+      ((bi >> 16) & 0xff).toByte,
+      ((bi >> 24) & 0xff).toByte,
+      ((bi >> 32) & 0xff).toByte,
+      ((bi >> 40) & 0xff).toByte,
+      ((bi >> 48) & 0xff).toByte,
+      ((bi >> 56) & 0xff).toByte)
+    assert(br.readUnsignedLongLE() == bi)
+    val exc = intercept[UnderflowException] { br.readByte() }
+  })
+
   // .equals is required to handle NaN
   test("readFloatBE") (forAll { i: Int =>
     val br = newReader(_.writeInt(i))