From d51c58e6d52265b2910bfb3090af8539f8a5a204 Mon Sep 17 00:00:00 2001
From: Andrew Noyes <andrew@weaselab.dev>
Date: Fri, 24 May 2024 13:38:41 -0700
Subject: [PATCH] Add operator== for Finger

---
 VersionedMap.cpp | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/VersionedMap.cpp b/VersionedMap.cpp
index f800dba..17b6276 100644
--- a/VersionedMap.cpp
+++ b/VersionedMap.cpp
@@ -449,6 +449,21 @@ struct Finger {
   Finger(Finger &&) = delete;
   Finger &operator=(Finger &&) = delete;
 
+  bool operator==(const Finger &other) const {
+    bool result = searchPathSize_ == other.searchPathSize_ &&
+                  (searchPathSize_ == 0 || backNode() == other.backNode());
+#ifndef NDEBUG
+    auto expected = searchPathSize_ == other.searchPathSize_ &&
+                    memcmp(searchPath, other.searchPath,
+                           searchPathSize_ * sizeof(searchPath[0])) == 0 &&
+                    (searchPathSize_ == 0 ||
+                     memcmp(direction + 1, other.direction + 1,
+                            (searchPathSize_ - 1) * sizeof(direction[0])) == 0);
+    assert(result == expected);
+#endif
+    return result;
+  }
+
 private:
   uint32_t searchPath[kPathLengthUpperBound];
   bool direction[kPathLengthUpperBound];
@@ -951,11 +966,7 @@ struct VersionedMap::Iterator::Impl {
   bool equals(const Impl &other) const {
     assert(map == other.map);
     assert(version == other.version);
-    if (finger.searchPathSize() == 0 || other.finger.searchPathSize() == 0) {
-      return finger.searchPathSize() == other.finger.searchPathSize();
-    }
-    return finger.backNode() == other.finger.backNode() &&
-           mutationIndex == other.mutationIndex;
+    return finger == other.finger && mutationIndex == other.mutationIndex;
   }
 };