[+] Sharded variant of block's header

dap_chain_block.h

@@ -43,15 +43,29 @@ typedef struct  dap_chain_block{
         uint32_t signature; /// @param signature @brief Magic number, always equels to DAP_CHAIN_BLOCK_SIGNATURE
         int32_t version; /// @param version @brief block version (be carefull, signed value, as Bitcoin has)
         uint32_t size; /// @param size of the whole block
-        dap_chain_hash_t prev_block; /// @param prev_block Hash of the previous block
         uint64_t timestamp; /// @param timestamp @brief Block create time timestamp
-        uint64_t difficulty; /// difficulty level
-        uint64_t nonce; /// Nonce value to allow header variation for mining
+	uint64_t difficulty; /// difficulty level
+	uint64_t nonce; /// Nonce value to allow header variation for mining
+	union{
+	    struct{ // Zero-level block without sharding
+	        dap_chain_hash_t prev_block; /// @param prev_block Hash of the previous block
+	        dap_chain_hash_t padding0; // 
+		uint32_t padding1; //
+		uint64_t padding2; // Always zero (should be well compresed) 
+	    };
+	    struct{
+	        dap_chain_hash_t prev_block_0lvl; /// @param prev_block Hash of the previous block
+	        dap_chain_hash_t prev_block_shard; /// @param prev_block Hash of the previous block
+		uint32_t shard_id; // Shard id
+		uint64_t nonce2; // Second NonCE for block mining inside the shard
+	    }
+	}
         dap_chain_hash_t root_sections;/// @param root_main Main tree's root for all sections's hashes
     } DAP_ALIGN_PACKED header;
     uint8_t sections[]; // Sections
 } DAP_ALIGN_PACKED dap_chain_block_t;
 
+
 dap_chain_block_t * dap_chain_block_new(dap_chain_hash_t * a_prev_block );
 
 dap_chain_section_t * dap_chain_block_create_section(dap_chain_block_t * a_block, uint32_t a_section_offset