Merge pull request #5128 from dumganhar/iss2789-perf-container

closed #2789: Adds a macro ‘’USE_STD_UNORDERED_MAP” for switching the implementation of Map<K, V> between using std::unordered_map and std::map.

cocos/base/CCMap.h

@@ -25,10 +25,17 @@
 #ifndef __CCMAP_H__
 #define __CCMAP_H__
 
+#define USE_STD_UNORDERED_MAP 1
+
 #include "ccMacros.h"
 #include "CCObject.h"
 #include <vector>
+
+#if USE_STD_UNORDERED_MAP
 #include <unordered_map>
+#else
+#include <map>
+#endif
 
 NS_CC_BEGIN
 
@@ -44,7 +51,11 @@ public:
     // ------------------------------------------
     // Iterators
     // ------------------------------------------
+#if USE_STD_UNORDERED_MAP
     typedef std::unordered_map<K, V> RefMap;
+#else
+    typedef std::map<K, V> RefMap;
+#endif
     
     typedef typename RefMap::iterator iterator;
     typedef typename RefMap::const_iterator const_iterator;
@@ -104,25 +115,39 @@ public:
     /** Sets capacity of the map */
     void reserve(ssize_t capacity)
     {
+#if USE_STD_UNORDERED_MAP
         _data.reserve(capacity);
+#endif
     }
     
     /** Returns the number of buckets in the Map container. */
     ssize_t bucketCount() const
     {
+#if USE_STD_UNORDERED_MAP
         return _data.bucket_count();
+#else
+        return 0;
+#endif
     }
     
     /** Returns the number of elements in bucket n. */
     ssize_t bucketSize(ssize_t n) const
     {
+#if USE_STD_UNORDERED_MAP
         return _data.bucket_size(n);
+#else
+        return 0;
+#endif
     }
     
     /** Returns the bucket number where the element with key k is located. */
     ssize_t bucket(const K& k) const
     {
+#if USE_STD_UNORDERED_MAP
         return _data.bucket(k);
+#else
+        return 0;
+#endif
     }
     
     /** The number of elements in the map. */