Add sharing_mapt::iterate

This gives a simple const iterator without copying the whole dataset.

Author: smowton

src/util/sharing_map.h

@@ -444,6 +444,18 @@ class sharing_mapt
     delta_viewt &delta_view,
     const bool only_common = true) const;
 
+  /// Call a function for every key-value pair in the map.
+  ///
+  /// Complexity: as \ref sharing_mapt::get_view
+  void
+  iterate(std::function<void(const key_type &k, const mapped_type &m)> f) const
+  {
+    if(empty())
+      return;
+
+    iterate(map, 0, f);
+  }
+
 #if !defined(_MSC_VER)
   /// Stats about sharing between several sharing map instances. An instance of
   /// this class is returned by the get_sharing_map_stats_* functions.

unit/util/sharing_map.cpp

@@ -297,7 +297,7 @@ TEST_CASE("Sharing map collisions", "[core][util]")
   REQUIRE(!sm.has_key(some_keyt(8)));
 }
 
-TEST_CASE("Sharing map views", "[core][util]")
+TEST_CASE("Sharing map views and iteration", "[core][util]")
 {
   SECTION("View of empty map")
   {
@@ -349,6 +349,25 @@ TEST_CASE("Sharing map views", "[core][util]")
     REQUIRE((pairs[3] == pt("l", "3")));
   }
 
+  SECTION("Iterate")
+  {
+    sharing_map_standardt sm;
+    fill(sm);
+
+    typedef std::pair<dstringt, std::string> pt;
+    std::vector<pt> pairs;
+
+    sm.iterate([&pairs](const irep_idt &key, const std::string &value) {
+      pairs.push_back({key, value});
+    });
+
+    std::sort(pairs.begin(), pairs.end());
+    REQUIRE(pairs.size() == 3);
+    REQUIRE((pairs[0] == pt("i", "0")));
+    REQUIRE((pairs[1] == pt("j", "1")));
+    REQUIRE((pairs[2] == pt("k", "2")));
+  }
+
   SECTION("Delta view (no sharing, same keys)")
   {
     sharing_map_standardt sm1;