From 7cf452da77206e8fdfcb64062d2fd2c0ea84ccc0 Mon Sep 17 00:00:00 2001
From: artemp <artem@mapnik.org>
Date: Wed, 11 Dec 2013 13:56:11 -0500
Subject: [PATCH] generic ```to_integral``` helper function (convert strongly
 typed enumeration values to underlying type)

---
 include/mapnik/symbolizer.hpp |  7 ++++++-
 src/symbolizer_keys.cpp       | 12 ++++++------
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/include/mapnik/symbolizer.hpp b/include/mapnik/symbolizer.hpp
index 44ed70f4f..9bc8dba49 100644
--- a/include/mapnik/symbolizer.hpp
+++ b/include/mapnik/symbolizer.hpp
@@ -370,11 +370,16 @@ boost::optional<T> get_optional(symbolizer_base const& sym, keys key)
     return boost::optional<T>();
 }
 
+template<typename Enum>
+constexpr auto to_integral(Enum e) -> typename std::underlying_type<Enum>::type
+{
+    return static_cast<typename std::underlying_type<Enum>::type>(e);
+}
+
 typedef std::tuple<const char*, mapnik::symbolizer_base::value_type, std::function<std::string(enumeration_wrapper)> > property_meta_type;
 property_meta_type const& get_meta(mapnik::keys key);
 mapnik::keys get_key(std::string const& name);
 
-
 // concrete symbolizer types
 struct MAPNIK_DECL point_symbolizer : public symbolizer_base {};
 struct MAPNIK_DECL line_symbolizer : public symbolizer_base {};
diff --git a/src/symbolizer_keys.cpp b/src/symbolizer_keys.cpp
index f553fb622..ec15d3efd 100644
--- a/src/symbolizer_keys.cpp
+++ b/src/symbolizer_keys.cpp
@@ -101,13 +101,13 @@ mapnik::keys get_key(std::string const& name)
 {
    std::string name_copy(name);
    boost::algorithm::replace_all(name_copy,"_","-");
-   for (unsigned i=0;i<static_cast<unsigned>(keys::MAX_SYMBOLIZER_KEY);++i)
+   for (unsigned i=0; i< to_integral(keys::MAX_SYMBOLIZER_KEY) ; ++i)
    {
-        property_meta_type const& item = key_meta[i];
-        if (name_copy == std::get<0>(item))
-        {
-            return static_cast<mapnik::keys>(i);
-        }
+       property_meta_type const& item = key_meta[i];
+       if (name_copy == std::get<0>(item))
+       {
+           return static_cast<mapnik::keys>(i);
+       }
    }
    throw std::runtime_error("no key found for '" + name + "'");
    return static_cast<mapnik::keys>(0);