avoid creating default initialised values if key doesn't exist

mapnik · Oct 27, 2011 · 0f5ab18 · 0f5ab18
1 parent 28e7c83
commit 0f5ab18
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Showing 3 changed files with 42 additions and 4 deletions.
diff --git a/include/mapnik/attribute.hpp b/include/mapnik/attribute.hpp
@@ -23,20 +23,31 @@
 #ifndef MAPNIK_ATTRIBUTE_HPP
 #define MAPNIK_ATTRIBUTE_HPP
 
+// mapnik
+#include <mapnik/value.hpp>
+// stl
 #include <string>
 
 namespace mapnik {
 
+static mapnik::value _null_value;
+
 struct attribute
 {
     std::string name_;
     explicit attribute(std::string const& name)
         : name_(name) {}
 
     template <typename V ,typename F>
-    V value(F const& f) const
+    V const& value(F const& f) const
     {
-        return f[name_];
+        typedef typename F::const_iterator const_iterator;
+        const_iterator itr = f.find(name_);
+        if (itr != f.end())
+        {
+            return itr->second;
+        }
+        return _null_value;
     }
     std::string const& name() const { return name_;}
 };

diff --git a/include/mapnik/feature.hpp b/include/mapnik/feature.hpp
@@ -65,6 +65,7 @@ struct feature : public properties,
     std::map<std::string,value> props_;
 public:
     typedef std::map<std::string,value>::iterator iterator;
+    typedef std::map<std::string,value>::const_iterator const_iterator;
     explicit feature(int id)
         : properties(props_),
           id_(id),
@@ -145,7 +146,7 @@ struct feature : public properties,
     {
         return props_;
     }
-    
+
     iterator begin()
     {
         return props_.begin();
@@ -155,7 +156,22 @@ struct feature : public properties,
     {
         return props_.end();
     }
+
+    const_iterator begin() const
+    {
+        return props_.begin();
+    }
 
+    const_iterator end() const
+    {
+        return props_.end();
+    }
+
+    const_iterator find(std::string const& key) const
+    {
+        return props_.find(key);
+    }
+
     std::string to_string() const
     {
         std::stringstream ss;

diff --git a/include/mapnik/metawriter.hpp b/include/mapnik/metawriter.hpp
@@ -47,11 +47,22 @@ struct placement;
 class metawriter_property_map
 {
 public:
+    typedef std::map<std::string, UnicodeString> property_map;
+    typedef property_map::const_iterator const_iterator;
+
     metawriter_property_map() {}
     UnicodeString const& operator[](std::string const& key) const;
     UnicodeString& operator[](std::string const& key) {return m_[key];}
+    std::map<std::string, UnicodeString>::const_iterator find(std::string const& key) const
+    {
+        return m_.find(key);
+    }
+    std::map<std::string, UnicodeString>::const_iterator end() const
+    {
+        return m_.end();
+    }
 private:
-    std::map<std::string, UnicodeString> m_;
+    property_map m_;
     UnicodeString not_found_;
 };