Use boost::unordered_map for mapBlockIndex

src/main.h

@@ -29,6 +29,8 @@
 #include <utility>
 #include <vector>
 
+#include <boost/unordered_map.hpp>
+
 class CBlockIndex;
 class CBloomFilter;
 class CInv;
@@ -81,11 +83,15 @@ static const unsigned char REJECT_DUST = 0x41;
 static const unsigned char REJECT_INSUFFICIENTFEE = 0x42;
 static const unsigned char REJECT_CHECKPOINT = 0x43;
 
+struct BlockHasher
+{
+    size_t operator()(const uint256& hash) const { return hash.GetLow64(); }
+};
 
 extern CScript COINBASE_FLAGS;
 extern CCriticalSection cs_main;
 extern CTxMemPool mempool;
-typedef std::map<uint256, CBlockIndex*> BlockMap;
+typedef boost::unordered_map<uint256, CBlockIndex*, BlockHasher> BlockMap;
 extern BlockMap mapBlockIndex;
 extern uint64_t nLastBlockTx;
 extern uint64_t nLastBlockSize;