From a209f961a67e9675bc34810ba66207b7a4028206 Mon Sep 17 00:00:00 2001
From: Mathew Sutcliffe <oktal3700@gmail.com>
Date: Mon, 4 Jul 2016 18:12:16 +0100
Subject: [PATCH] refs #698 Added unorderedEqualsByKeys method for sequences.

---
 src/blackmisc/sequence.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/blackmisc/sequence.h b/src/blackmisc/sequence.h
index f17673b4d..4180d4d30 100644
--- a/src/blackmisc/sequence.h
+++ b/src/blackmisc/sequence.h
@@ -463,6 +463,16 @@ namespace BlackMisc
             return partiallySorted(n, BlackMisc::Predicates::MemberLess(key1, keys...));
         }
 
+        //! Return true if this container equals another container, considering only the given element members.
+        //! Order of elements is not considered; this is implemented using a transient sort, so don't overuse.
+        template <class U, class Key0, class... Keys>
+        bool unorderedEqualsByKeys(const U &other, Key0 k0, Keys... keys) const
+        {
+            if (equalPointers(this, &other)) { return true; }
+            if (size() != other.size()) { return false; }
+            return sorted(k0, keys...).equalsByKeys(other.sorted(k0, keys...));
+        }
+
         //! Split up the sequence into subsequences for which the given predicate returns the same value.
         template <class Predicate>
         auto separate(Predicate p) const -> QMap<decltype(p(std::declval<T>())), CSequence>