Finished new position unpickling code.

Pickling still has to be written.

1 files changed, 37 insertions, 0 deletions

diff --git a/src/dotty/tools/dotc/core/pickling/PositionUnpickler.scala b/src/dotty/tools/dotc/core/pickling/PositionUnpickler.scala
new file mode 100644
index 000000000..c341d58cc
--- /dev/null
+++ b/src/dotty/tools/dotc/core/pickling/PositionUnpickler.scala
@@ -0,0 +1,37 @@
+package dotty.tools
+package dotc
+package core
+package pickling
+
+import util.Positions._
+import collection.mutable
+import TastyBuffer.Addr
+
+object PositionUnpickler {
+  type AddrToPosition = mutable.HashMap[Addr, Position]
+}
+
+/** Unpickler for tree positions */
+class PositionUnpickler(reader: TastyReader) {
+  import PositionUnpickler._
+  import reader._
+
+  def unpickle(): (Position, AddrToPosition) = {
+    val positions = new mutable.HashMap[Addr, Position] // Dotty deviation: Can't use new AddrToPosition here. TODO: fix this!
+    val sourceLength = readNat()
+    def readDelta() = if (isAtEnd) 0 else readInt()
+    var curIndex: Addr = Addr(readDelta())
+    while (!isAtEnd) {
+      val delta1 = readDelta()
+      val delta2 = readDelta()
+      val (startDelta, endDelta, indexDelta) = 
+        if (delta2 <= 0) (delta1, -delta2, readDelta())
+        else if (delta1 < 0) (0, -delta1, delta2)
+        else (delta1, 0, delta2)
+      positions(curIndex) = Position(startDelta, endDelta, 0) 
+        // make non-synthetic position; will be made synthetic by normalization.
+      curIndex += indexDelta
+    }
+    (Position(0, sourceLength), positions)
+  }
+}
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