Add getblocksubsidy RPC command to return the block reward for a given

block, taking into account the mining slow start.

src/rpcclient.cpp

@@ -95,7 +95,8 @@ static const CRPCConvertParam vRPCConvertParams[] =
     { "zcrawpour", 2 },
     { "zcrawpour", 3 },
     { "zcrawpour", 4 },
-    { "zcbenchmark", 1 }
+    { "zcbenchmark", 1 },
+    { "getblocksubsidy", 0}
 };
 
 class CRPCConvertTable

src/rpcmining.cpp

@@ -766,3 +766,27 @@ Value estimatepriority(const Array& params, bool fHelp)
 
     return mempool.estimatePriority(nBlocks);
 }
+
+Value getblocksubsidy(const Array& params, bool fHelp)
+{
+    if (fHelp || params.size() != 1)
+        throw runtime_error(
+            "getblocksubsidy index\n"
+            "\nReturns block subsidy reward, taking into account the mining slow start, of block at index provided.\n"
+            "\nArguments:\n"
+            "1. index         (numeric, required) The block index\n"
+            "\nResult:\n"
+            "amount           (numeric) The block reward amount in ZEC.\n"
+            "\nExamples:\n"
+            + HelpExampleCli("getblocksubsidy", "1000")
+            + HelpExampleRpc("getblockubsidy", "1000")
+        );
+
+    LOCK(cs_main);
+    int nHeight = params[0].get_int();
+    if (nHeight < 0 || nHeight > chainActive.Height())
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Block height out of range");
+
+    CAmount nReward = GetBlockSubsidy(nHeight, Params().GetConsensus());
+    return ValueFromAmount(nReward);
+}

src/rpcserver.cpp

@@ -304,6 +304,7 @@ static const CRPCCommand vRPCCommands[] =
     { "mining",             "getnetworkhashps",       &getnetworkhashps,       true  },
     { "mining",             "prioritisetransaction",  &prioritisetransaction,  true  },
     { "mining",             "submitblock",            &submitblock,            true  },
+    { "mining",             "getblocksubsidy",        &getblocksubsidy,        true  },
 
 #ifdef ENABLE_WALLET
     /* Coin generation */

src/rpcserver.h

@@ -240,6 +240,8 @@ extern json_spirit::Value getchaintips(const json_spirit::Array& params, bool fH
 extern json_spirit::Value invalidateblock(const json_spirit::Array& params, bool fHelp);
 extern json_spirit::Value reconsiderblock(const json_spirit::Array& params, bool fHelp);
 
+extern json_spirit::Value getblocksubsidy(const json_spirit::Array& params, bool fHelp);
+
 // in rest.cpp
 extern bool HTTPReq_REST(AcceptedConnection *conn,
                   const std::string& strURI,