From 2827eb5873257e7f8d4eef29036f453612aabec5 Mon Sep 17 00:00:00 2001
From: Eduard Valeyev <eduard@valeyev.net>
Date: Mon, 24 May 2021 15:22:10 -0400
Subject: [PATCH] Range avoids serializes rank only once and retains
 compatibility with old archives

---
 src/TiledArray/range.h | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/TiledArray/range.h b/src/TiledArray/range.h
index 3f4e809d37..c6cb472951 100644
--- a/src/TiledArray/range.h
+++ b/src/TiledArray/range.h
@@ -1118,7 +1118,19 @@ class Range {
 
   template <typename Archive>
   void serialize(Archive& ar) {
-    ar& rank_& datavec_& offset_& volume_;
+    ar& rank_;
+    const auto four_x_rank = rank_ << 2;
+    // read via madness::archive::wrap to be able to
+    // - avoid having to serialize datavec_'s size
+    // - read old archives that represented datavec_ by bare ptr
+    if constexpr (madness::archive::is_input_archive<Archive>::value) {
+      datavec_.resize(four_x_rank);
+      ar >> madness::archive::wrap(datavec_.data(), four_x_rank);
+    } else if constexpr (madness::archive::is_output_archive<Archive>::value) {
+      ar << madness::archive::wrap(datavec_.data(), four_x_rank);
+    } else
+      abort();  // unreachable
+    ar& offset_& volume_;
   }
 
   void swap(Range_& other) {