Make 30bit nanoseconds field always positive

gnieh · Jul 10, 2024 · 74323c6 · 74323c6
1 parent fba395b
commit 74323c6
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Showing 2 changed files with 13 additions and 1 deletion.
diff --git a/msgpack/src/main/scala/fs2/data/msgpack/low/model.scala b/msgpack/src/main/scala/fs2/data/msgpack/low/model.scala
@@ -48,7 +48,10 @@ object MsgpackItem {
     * @param combined [[nanoseconds]] and [[seconds]] combined into a signle 64-bit value
     */
   case class Timestamp64(combined: Long) extends MsgpackItem {
-    val nanoseconds: Int = (combined >> 34).toInt // we are sure that (x: Long) >> 34 fits in an int
+    /* We are sure that (x: Long) >> 34 fits in an int but we also need to add a mask so that we don't end up with
+     * a negative number.
+     */
+    val nanoseconds: Int = (0x000000003fffffffL & (combined >> 34)).toInt
     val seconds: Long = combined & 0x00000003ffffffffL
   }
   case class Timestamp96(nanoseconds: Int, seconds: Long) extends MsgpackItem

diff --git a/msgpack/src/test/scala/fs2/data/msgpack/ParserSpec.scala b/msgpack/src/test/scala/fs2/data/msgpack/ParserSpec.scala
@@ -21,6 +21,7 @@ import scodec.bits.*
 import weaver.SimpleIOSuite
 import fs2.*
 import fs2.data.msgpack.low.MsgpackItem
+
 import java.nio.charset.StandardCharsets
 
 object ParserSpec extends SimpleIOSuite {
@@ -323,4 +324,12 @@ object ParserSpec extends SimpleIOSuite {
 
     (s1 ++ s2).compile.foldMonoid
   }
+
+  pureTest("Timestamp64 nanoseconds field should always be positive") {
+    val nums = List(
+      0xFFFFFFFFFFFFFFFFL,
+      0b1000000000000000000000000000000000000000000000000000000000000000L
+    )
+    forEach(nums)(x => expect(MsgpackItem.Timestamp64(x).nanoseconds > 0))
+  }
 }