From 6fc51c1b49cc2470591d6612622a9f8f543c557c Mon Sep 17 00:00:00 2001
From: Patrick Fasano <patrick@patrickfasano.com>
Date: Thu, 21 Jul 2022 12:19:58 -0400
Subject: [PATCH] execution: Overloads of for_each and for_each_m taking
 ExecutionPolicy

* Adds additional overloads to `for_each` and `for_each_m` that accept execution policies.
* Execution policy is applied to the loop over subsets.
---
 parallel_hashmap/phmap.h | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/parallel_hashmap/phmap.h b/parallel_hashmap/phmap.h
index 4e357c7..a6592bc 100644
--- a/parallel_hashmap/phmap.h
+++ b/parallel_hashmap/phmap.h
@@ -3318,14 +3318,41 @@ public:
         }
     }
 
+#if __cplusplus >= 201703L
+    template <class ExecutionPolicy, class F>
+    void for_each(ExecutionPolicy&& policy, F&& fCallback) const {
+        std::for_each(
+            std::forward<ExecutionPolicy>(policy), sets_.begin(), sets_.end(),
+            [&](auto const& inner) {
+                typename Lockable::SharedLock m(const_cast<Inner&>(inner));
+                std::for_each(inner.set_.begin(), inner.set_.end(), fCallback);
+            }
+        );
+    }
+#endif
+
     // this version allows to modify the values
-    void for_each_m(std::function<void (value_type&)> && fCallback) {
+    template <class F>
+    void for_each_m(F&& fCallback) {
         for (auto& inner : sets_) {
             typename Lockable::UniqueLock m(const_cast<Inner&>(inner));
             std::for_each(inner.set_.begin(), inner.set_.end(), fCallback);
         }
     }
 
+#if __cplusplus >= 201703L
+    template <class ExecutionPolicy, class F>
+    void for_each_m(ExecutionPolicy&& policy, F&& fCallback) {
+        std::for_each(
+            std::forward<ExecutionPolicy>(policy), sets_.begin(), sets_.end(),
+            [&](auto& inner) {
+                typename Lockable::UniqueLock m(const_cast<Inner&>(inner));
+                std::for_each(inner.set_.begin(), inner.set_.end(), fCallback);
+            }
+        );
+    }
+#endif
+
     // Extension API: support for heterogeneous keys.
     //
     //   std::unordered_set<std::string> s;