From b4eea9f1fee2b6c8ff18d9423f55ab1b5041bc28 Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Mon, 8 Feb 2021 09:38:17 +1000
Subject: [PATCH] map/multi_fixed: add `erase_keys`

---
 map/multi_fixed.hpp      | 13 +++++++++++++
 test/map/multi_fixed.cpp |  9 +++++++++
 2 files changed, 22 insertions(+)

diff --git a/map/multi_fixed.hpp b/map/multi_fixed.hpp
index bb18302d..9393acfa 100644
--- a/map/multi_fixed.hpp
+++ b/map/multi_fixed.hpp
@@ -236,6 +236,19 @@ namespace cruft::map {
             m_store.data[m_size].~value_type ();
         }
 
+        template <typename IteratorT>
+        void
+        erase_keys (IteratorT first, IteratorT last)
+        {
+            CHECK (std::is_sorted (first, last));
+
+            // HACK: This is hopelessly naive, but it works.
+            for (auto cursor = first; cursor != last; ++cursor)
+                if (auto pos = find (*cursor); pos != end ())
+                    erase (pos);
+        }
+
+
         std::size_t erase (key_type const&);
 
         bool empty (void) const { return m_size == 0; }
diff --git a/test/map/multi_fixed.cpp b/test/map/multi_fixed.cpp
index 0225fbe1..3f13bcc0 100644
--- a/test/map/multi_fixed.cpp
+++ b/test/map/multi_fixed.cpp
@@ -87,6 +87,15 @@ int main ()
         tap.expect_eq (init, expected, "erase of last element");
     }
 
+    {
+        cruft::map::multi_fixed<4, int, int> init {{ {0,0}, {1,1}, {2,2}, {3,3} }};
+        static constexpr int keys[] = { 1, 3 };
+        init.erase_keys (std::begin (keys), std::end (keys));
+        cruft::map::multi_fixed<4, int, int> expected {{ {0,0}, {2,2} }};
+        tap.expect_eq (init, expected, "erase_keys");
+    }
+
+
     test_sorted_iterators (tap);
     test_bad_alloc (tap);