Use Long to back the UInt64 type (#1109)

* Use Long to back the UInt64 type

* Define comparison operators between UInt64 and MilliSatoshi

eclair-core/src/main/scala/fr/acinq/eclair/MilliSatoshi.scala

@@ -16,7 +16,6 @@
 
 package fr.acinq.eclair
 
-import com.google.common.primitives.UnsignedLongs
 import fr.acinq.bitcoin.{Btc, BtcAmount, MilliBtc, Satoshi, btc2satoshi, millibtc2satoshi}
 
 /**
@@ -41,7 +40,6 @@ case class MilliSatoshi(private val underlying: Long) extends Ordered[MilliSatos
   override def compare(other: MilliSatoshi): Int = underlying.compareTo(other.underlying)
   // Since BtcAmount is a sealed trait that MilliSatoshi cannot extend, we need to redefine comparison operators.
   def compare(other: BtcAmount): Int = compare(other.toMilliSatoshi)
-  def compareUnsigned(other: UInt64): Int = UnsignedLongs.compare(underlying, other.toBigInt.longValue())
   def <=(other: BtcAmount): Boolean = compare(other) <= 0
   def >=(other: BtcAmount): Boolean = compare(other) >= 0
   def <(other: BtcAmount): Boolean = compare(other) < 0

eclair-core/src/main/scala/fr/acinq/eclair/UInt64.scala

@@ -16,40 +16,40 @@
 
 package fr.acinq.eclair
 
-import java.math.BigInteger
-
+import com.google.common.primitives.UnsignedLongs
 import scodec.bits.ByteVector
+import scodec.bits.HexStringSyntax
 
-case class UInt64(private val underlying: BigInt) extends Ordered[UInt64] {
+case class UInt64(private val underlying: Long) extends Ordered[UInt64] {
 
-  require(underlying >= 0, s"uint64 must be positive (actual=$underlying)")
-  require(underlying <= UInt64.MaxValueBigInt, s"uint64 must be < 2^64 -1 (actual=$underlying)")
+  override def compare(o: UInt64): Int = UnsignedLongs.compare(underlying, o.underlying)
+  private def compare(other: MilliSatoshi): Int = other.toLong match {
+    case l if l < 0 => 1                    // if @param 'other' is negative then is always smaller than 'this'
+    case _ => compare(UInt64(other.toLong)) // we must do an unsigned comparison here because the uint64 can exceed the capacity of MilliSatoshi class
+  }
 
-  override def compare(o: UInt64): Int = underlying.compare(o.underlying)
+  def <(other: MilliSatoshi): Boolean = compare(other) < 0
+  def >(other: MilliSatoshi): Boolean = compare(other) > 0
+  def <=(other: MilliSatoshi): Boolean = compare(other) <= 0
+  def >=(other: MilliSatoshi): Boolean = compare(other) >= 0
 
-  def toByteVector: ByteVector = ByteVector.view(underlying.toByteArray.takeRight(8))
+  def toByteVector: ByteVector = ByteVector.fromLong(underlying)
 
-  def toBigInt: BigInt = underlying
+  def toBigInt: BigInt = (BigInt(underlying >>> 1) << 1) + (underlying & 1)
 
-  override def toString: String = underlying.toString
+  override def toString: String = UnsignedLongs.toString(underlying, 10)
 }
 
-
 object UInt64 {
 
-  private val MaxValueBigInt = BigInt(new BigInteger("ffffffffffffffff", 16))
+  val MaxValue = UInt64(hex"0xffffffffffffffff")
 
-  val MaxValue = UInt64(MaxValueBigInt)
-
-  def apply(bin: ByteVector) = new UInt64(new BigInteger(1, bin.toArray))
-
-  def apply(value: Long) = new UInt64(BigInt(value))
+  def apply(bin: ByteVector): UInt64 = UInt64(bin.toLong(signed = false))
 
   object Conversions {
 
     implicit def intToUint64(l: Int) = UInt64(l)
 
     implicit def longToUint64(l: Long) = UInt64(l)
   }
-
 }

eclair-core/src/main/scala/fr/acinq/eclair/channel/Commitments.scala

@@ -149,8 +149,7 @@ object Commitments {
     val outgoingHtlcs = reduced.htlcs.filter(_.direction == IN)
 
     val htlcValueInFlight = outgoingHtlcs.map(_.add.amountMsat).sum
-    // we must use unsigned comparison here because 'maxHtlcValueInFlightMsat' is effectively an uint64 and can exceed the capacity of MilliSatoshi class
-    if (htlcValueInFlight.compareUnsigned(commitments1.remoteParams.maxHtlcValueInFlightMsat) > 0) {
+    if (commitments1.remoteParams.maxHtlcValueInFlightMsat < htlcValueInFlight) {
       // TODO: this should be a specific UPDATE error
       return Left(HtlcValueTooHighInFlight(commitments.channelId, maximum = commitments1.remoteParams.maxHtlcValueInFlightMsat, actual = htlcValueInFlight))
     }
@@ -185,8 +184,7 @@ object Commitments {
     val incomingHtlcs = reduced.htlcs.filter(_.direction == IN)
 
     val htlcValueInFlight = incomingHtlcs.map(_.add.amountMsat).sum
-    // we must use unsigned comparison here because 'maxHtlcValueInFlightMsat' is effectively an uint64 and can exceed the capacity of MilliSatoshi class
-    if (htlcValueInFlight.compareUnsigned(commitments1.localParams.maxHtlcValueInFlightMsat) > 0) {
+    if (commitments1.localParams.maxHtlcValueInFlightMsat < htlcValueInFlight) {
       throw HtlcValueTooHighInFlight(commitments.channelId, maximum = commitments1.localParams.maxHtlcValueInFlightMsat, actual = htlcValueInFlight)
     }
 

eclair-core/src/test/scala/fr/acinq/eclair/CoinUtilsSpec.scala

@@ -18,21 +18,9 @@ package fr.acinq.eclair
 
 import fr.acinq.bitcoin.{Btc, MilliBtc, Satoshi}
 import org.scalatest.FunSuite
-import scodec.bits._
-
 
 class CoinUtilsSpec  extends FunSuite {
 
-  test("use unsigned comparison when comparing millisatoshis to uint64") {
-    assert(MilliSatoshi(123).compareUnsigned(UInt64(123)) == 0)
-    assert(MilliSatoshi(1234).compareUnsigned(UInt64(123)) > 0)
-    assert(MilliSatoshi(123).compareUnsigned(UInt64(1234)) < 0)
-    assert(MilliSatoshi(123).compareUnsigned(UInt64(hex"ffffffffffffffff")) < 0)
-    assert(MilliSatoshi(-123).compareUnsigned(UInt64(hex"ffffffffffffffff")) < 0)
-    assert(MilliSatoshi(Long.MaxValue).compareUnsigned(UInt64(hex"7fffffffffffffff")) == 0) // 7fffffffffffffff == Long.MaxValue
-    assert(MilliSatoshi(Long.MaxValue).compareUnsigned(UInt64(hex"8000000000000000")) < 0)  // 8000000000000000 == Long.MaxValue + 1
-  }
-
   test("Convert string amount to the correct BtcAmount") {
     val am_btc: MilliSatoshi = CoinUtils.convertStringAmountToMsat("1", BtcUnit.code)
     assert(am_btc == MilliSatoshi(100000000000L))

eclair-core/src/test/scala/fr/acinq/eclair/UInt64Spec.scala

@@ -22,23 +22,63 @@ import scodec.bits._
 
 class UInt64Spec extends FunSuite {
 
-  test("handle values from 0 to 2^63-1") {
+  test("handle values from 0 to 2^64-1") {
     val a = UInt64(hex"0xffffffffffffffff")
     val b = UInt64(hex"0xfffffffffffffffe")
     val c = UInt64(42)
     val z = UInt64(0)
+    val l = UInt64(Long.MaxValue)
+    val l1 = UInt64(hex"8000000000000000") // Long.MaxValue + 1
+
     assert(a > b)
+    assert(a.toBigInt > b.toBigInt)
     assert(b < a)
-    assert(z < a && z < b && z < c)
+    assert(b.toBigInt < a.toBigInt)
+    assert(l.toBigInt < l1.toBigInt)
+    assert(z < a && z < b && z < c && z < l && c < l && l < l1 && l < b && l < a)
     assert(a == a)
-    assert(a.toByteVector === hex"0xffffffffffffffff")
-    assert(a.toString === "18446744073709551615")
-    assert(b.toByteVector === hex"0xfffffffffffffffe")
+    assert(a == UInt64.MaxValue)
+
+    assert(l.toByteVector == hex"7fffffffffffffff")
+    assert(l.toString == Long.MaxValue.toString)
+    assert(l.toBigInt == BigInt(Long.MaxValue))
+
+    assert(l1.toByteVector == hex"8000000000000000")
+    assert(l1.toString == "9223372036854775808")
+    assert(l1.toBigInt == BigInt("9223372036854775808"))
+
+    assert(a.toByteVector === hex"ffffffffffffffff")
+    assert(a.toString === "18446744073709551615") // 2^64 - 1
+    assert(a.toBigInt === BigInt("18446744073709551615"))
+
+    assert(b.toByteVector === hex"fffffffffffffffe")
     assert(b.toString === "18446744073709551614")
-    assert(c.toByteVector === hex"0x2a")
+    assert(b.toBigInt === BigInt("18446744073709551614"))
+
+    assert(c.toByteVector === hex"00000000000002a")
     assert(c.toString === "42")
-    assert(z.toByteVector === hex"0x00")
+    assert(c.toBigInt === BigInt("42"))
+
+    assert(z.toByteVector === hex"000000000000000")
     assert(z.toString === "0")
+    assert(z.toBigInt === BigInt("0"))
+
+    assert(UInt64(hex"ff").toByteVector ==  hex"0000000000000ff")
+    assert(UInt64(hex"800").toByteVector == hex"000000000000800")
   }
 
+  test("use unsigned comparison when comparing millisatoshis to uint64") {
+    assert(UInt64(123) <= MilliSatoshi(123) && UInt64(123) >= MilliSatoshi(123))
+    assert(UInt64(123) < MilliSatoshi(1234))
+    assert(UInt64(1234) > MilliSatoshi(123))
+    assert(UInt64(hex"ffffffffffffffff") > MilliSatoshi(123))
+    assert(UInt64(hex"ffffffffffffffff") > MilliSatoshi(-123))
+    assert(UInt64(hex"7ffffffffffffffe") < MilliSatoshi(Long.MaxValue))  // 7ffffffffffffffe == Long.MaxValue - 1
+    assert(UInt64(hex"7fffffffffffffff") <= MilliSatoshi(Long.MaxValue) && UInt64(hex"7fffffffffffffff") >= MilliSatoshi(Long.MaxValue)) // 7fffffffffffffff == Long.MaxValue
+    assert(UInt64(hex"8000000000000000") > MilliSatoshi(Long.MaxValue))  // 8000000000000000 == Long.MaxValue + 1
+    assert(UInt64(1) > MilliSatoshi(-1))
+    assert(UInt64(0) > MilliSatoshi(Long.MinValue))
+  }
+
+
 }