Fix path serialised_size calculation

achamayou · achamayou · commit f4997c04877a · 2023-12-15T10:58:09.000Z
diff --git a/merklecpp.h b/merklecpp.h
@@ -424,7 +424,14 @@ namespace merkle
     /// @brief The size of the serialised path in number of bytes
     size_t serialised_size() const
     {
-      return sizeof(_leaf) + elements.size() * sizeof(Element);
+      return sizeof(_leaf) +
+      sizeof(uint64_t) + // leaf index
+      sizeof(uint64_t) + // max index
+      sizeof(uint64_t) + // number of elements
+      elements.size() * (
+        sizeof(Element::hash) + // hash
+        sizeof(uint8_t) // direction
+      );
     }
 
     /// @brief Index of the leaf of the path
diff --git a/test/paths.cpp b/test/paths.cpp
@@ -56,6 +56,10 @@ int main()
         auto path = mt.path(i);
         if (!path->verify(root))
           throw std::runtime_error("path verification failed");
+        std::vector<uint8_t> serialised_path;
+        path->serialise(serialised_path);
+        if (path->serialised_size() != serialised_path.size())
+          throw std::runtime_error("serialised_size() != serialised_path.size()");
       }
     }
 

Original file line number	Diff line number	Diff line change
`@@ -56,6 +56,10 @@ int main()`
`56`	`56`	`auto path = mt.path(i);`
`57`	`57`	`if (!path->verify(root))`
`58`	`58`	`throw std::runtime_error("path verification failed");`
	`59`	`+ std::vector<uint8_t> serialised_path;`
	`60`	`+ path->serialise(serialised_path);`
	`61`	`+ if (path->serialised_size() != serialised_path.size())`
	`62`	`+ throw std::runtime_error("serialised_size() != serialised_path.size()");`
`59`	`63`	`}`
`60`	`64`	`}`
`61`	`65`