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

CHANGES

@@ -15,6 +15,9 @@ New Features:
   * util-core: Added `writeBytes(Buf)` to the ByteWriter abstract class to allow
     for efficient writing of the `c.t.io.Buf` type. ``RB_ID=917094``
 
+  * util-core: Added `ByteReader.readUnsignedLongBE` and `ByteReader.readUnsignedLongLE`.
+    ``RB_ID=917289``
+
 API Changes:
 
   * util-collection: Removed deprecated `c.t.u.JMapWrapper`. Use

util-core/src/main/scala/com/twitter/io/ByteReader.scala

@@ -106,6 +106,16 @@ trait ByteReader extends AutoCloseable {
    */
   def readLongLE(): Long
 
+  /**
+    * Extract 64 bits and interpret as a big endian unsigned integer, advancing the byte cursor by 8.
+    */
+  def readUnsignedLongBE(): BigInt
+
+  /**
+    * Extract 64 bits and interpret as a little endian unsigned integer, advancing the byte cursor by 8.
+    */
+  def readUnsignedLongLE(): BigInt
+
   /**
    * Extract 32 bits and interpret as a big endian floating point, advancing the byte cursor by 4.
    */
@@ -187,6 +197,10 @@ private[twitter] trait ProxyByteReader extends ByteReader {
 
   def readLongLE(): Long = reader.readLongLE()
 
+  def readUnsignedLongBE(): BigInt = reader.readUnsignedLongBE()
+
+  def readUnsignedLongLE(): BigInt = reader.readUnsignedLongLE()
+
   def readFloatBE(): Float = reader.readFloatBE()
 
   def readFloatLE(): Float = reader.readFloatLE()
@@ -384,6 +398,39 @@ private class ByteReaderImpl(buf: Buf) extends ByteReader {
     ret
   }
 
+  def readUnsignedLongBE(): BigInt = {
+    checkRemaining(8)
+    val ret =
+      (buf.get(pos + 7) & 0xff).toLong        |
+      (buf.get(pos + 6) & 0xff).toLong <<  8  |
+      (buf.get(pos + 5) & 0xff).toLong << 16  |
+      (buf.get(pos + 4) & 0xff).toLong << 24  |
+      (buf.get(pos + 3) & 0xff).toLong << 32  |
+      (buf.get(pos + 2) & 0xff).toLong << 40  |
+      (buf.get(pos + 1) & 0xff).toLong << 48  |
+      BigInt((buf.get(pos) & 0xff).toLong) << 56
+    pos += 8
+
+    ret
+  }
+
+  def readUnsignedLongLE(): BigInt = {
+    checkRemaining(8)
+    val ret =
+      (buf.get(pos    ) & 0xff).toLong       |
+      (buf.get(pos + 1) & 0xff).toLong <<  8 |
+      (buf.get(pos + 2) & 0xff).toLong << 16 |
+      (buf.get(pos + 3) & 0xff).toLong << 24 |
+      (buf.get(pos + 4) & 0xff).toLong << 32 |
+      (buf.get(pos + 5) & 0xff).toLong << 40 |
+      (buf.get(pos + 6) & 0xff).toLong << 48 |
+      BigInt(buf.get(pos + 7) & 0xff) << 56
+    pos += 8
+
+    ret
+  }
+
+
   // - Floating Point -
   def readFloatBE(): Float = JFloat.intBitsToFloat(readIntBE())
 

util-core/src/test/scala/com/twitter/io/ByteReaderTest.scala

@@ -1,7 +1,9 @@
 package com.twitter.io
 
 import java.lang.{Double => JDouble, Float => JFloat}
+
 import org.junit.runner.RunWith
+import org.scalacheck.Gen
 import org.scalatest.FunSuite
 import org.scalatest.junit.JUnitRunner
 import org.scalatest.prop.GeneratorDrivenPropertyChecks
@@ -154,6 +156,39 @@ class ByteReaderTest extends FunSuite with GeneratorDrivenPropertyChecks {
     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 = new ByteReaderImpl(Buf.Empty) { override def readIntBE() = i }