added another command for getting difficulty numbers

src/currency_core/blockchain_storage.cpp

@@ -2665,6 +2665,46 @@ void blockchain_storage::print_db_cache_perfeormance_data() const
   );
 }
 //------------------------------------------------------------------
+void blockchain_storage::get_last_n_x_blocks(uint64_t n, bool pos_blocks, std::list<std::shared_ptr<const block_extended_info>>& blocks) const
+{
+  uint64_t count = 0;
+  bool looking_for_a_pos = true;
+  for (uint64_t i = m_db_blocks.size() - 1; i != 0; --i)
+  {
+    auto block_ptr = m_db_blocks[i];
+    if (is_pos_block(block_ptr->bl) == pos_blocks)
+    {
+      blocks.push_back(block_ptr);
+      ++count;
+      if (count >= n)
+        break;
+    }
+  }
+}
+//------------------------------------------------------------------
+void blockchain_storage::print_last_n_difficulty_numbers(uint64_t n) const
+{
+
+  std::stringstream ss;
+  std::list<std::shared_ptr<const block_extended_info>> pos_blocks;
+  std::list<std::shared_ptr<const block_extended_info>> pow_blocks;
+  
+  get_last_n_x_blocks(n, true, pos_blocks);
+  get_last_n_x_blocks(n, false, pow_blocks);
+  ss << "PoS blocks difficulty:" << ENDL;
+  for (auto& bl_ptr : pos_blocks)
+  {
+    ss << bl_ptr->cumulative_diff_precise << ENDL;
+  }
+
+  ss << "PoW blocks difficulty:" << ENDL;
+  for (auto& bl_ptr : pow_blocks)
+  {
+    ss << bl_ptr->cumulative_diff_precise << ENDL;
+  }
+
+}
+//------------------------------------------------------------------
 void blockchain_storage::print_blockchain_outs_stat() const
 {
   LOG_ERROR("NOT IMPLEMENTED YET");

src/currency_core/blockchain_storage.h

@@ -430,6 +430,7 @@ namespace currency
     void print_blockchain_outs(const std::string& file) const;
     void print_blockchain_outs_stat() const;
     void print_db_cache_perfeormance_data() const;
+    void print_last_n_difficulty_numbers(uint64_t n) const;
     bool calc_tx_cummulative_blob(const block& bl)const;
     bool get_outs_index_stat(outs_index_stat& outs_stat)const;
     bool print_lookup_key_image(const crypto::key_image& ki) const;
@@ -561,7 +562,7 @@ namespace currency
     bool validate_alt_block_txs(const block& b, const crypto::hash& id, std::set<crypto::key_image>& collected_keyimages, alt_block_extended_info& abei, const alt_chain_type& alt_chain, uint64_t split_height, uint64_t& ki_lookup_time_total) const;
     bool update_alt_out_indexes_for_tx_in_block(const transaction& tx, alt_block_extended_info& abei)const;
     bool get_transaction_from_pool_or_db(const crypto::hash& tx_id, std::shared_ptr<transaction>& tx_ptr, uint64_t min_allowed_block_height = 0) const;
-
+    void get_last_n_x_blocks(uint64_t n, bool pos_blocks, std::list<std::shared_ptr<const block_extended_info>>& blocks) const;
     bool prevalidate_miner_transaction(const block& b, uint64_t height, bool pos)const;
     bool rollback_blockchain_switching(std::list<block>& original_chain, size_t rollback_height);
     bool add_transaction_from_block(const transaction& tx, const crypto::hash& tx_id, const crypto::hash& bl_id, uint64_t bl_height, uint64_t timestamp);

src/daemon/daemon_commands_handler.h

@@ -68,6 +68,7 @@ public:
     m_cmd_binder.set_handler("print_block_from_hex_blob", boost::bind(&daemon_commands_handler::print_block_from_hex_blob, this, _1), "Unserialize block from hex binary data to json-like representation");
     m_cmd_binder.set_handler("print_tx_from_hex_blob", boost::bind(&daemon_commands_handler::print_tx_from_hex_blob, this, _1), "Unserialize transaction from hex binary data to json-like representation");
     m_cmd_binder.set_handler("print_tx_outputs_usage", boost::bind(&daemon_commands_handler::print_tx_outputs_usage, this, _1), "Analyse if tx outputs for involved in subsequent transactions");
+    m_cmd_binder.set_handler("print_difficulties_of_last_n_blocks", boost::bind(&daemon_commands_handler::print_difficulties_of_last_n_blocks, this, _1), "Print difficulties of last n blocks");
 
   }
 
@@ -696,8 +697,26 @@ private:
     m_srv.get_payload_object().get_core().get_blockchain_storage().print_tx_outputs_lookup(tx_hash);
     return true;
   }
+  //--------------------------------------------------------------------------------
+  bool print_difficulties_of_last_n_blocks(const std::vector<std::string>& args)
+  {
+    if (args.empty())
+    {
+      std::cout << "expected: n - number of blocks to read" << std::endl;
+      return true;
+    }
 
+    const std::string& amount = args.front();
+    uint64_t n = 0;
+    if (!epee::string_tools::get_xtype_from_string(n, amount))
+    {
+      std::cout << "unable to convert to number '" << amount << "'" << std::endl;
+      return true;
+    }
 
+    m_srv.get_payload_object().get_core().get_blockchain_storage().print_last_n_difficulty_numbers(n);
+    return true;
+  }
   //--------------------------------------------------------------------------------
   bool print_pool(const std::vector<std::string>& args)
   {