text: // Copyright (c) 2006-2013, Andrey N. Sabelnikov, www.sabelnikov.net
  // All rights reserved.
  // 
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are met:
  // * Redistributions of source code must retain the above copyright
  // notice, this list of conditions and the following disclaimer.
  // * Redistributions in binary form must reproduce the above copyright
  // notice, this list of conditions and the following disclaimer in the
  // documentation and/or other materials provided with the distribution.
  // * Neither the name of the Andrey N. Sabelnikov nor the
  // names of its contributors may be used to endorse or promote products
  // derived from this software without specific prior written permission.
  // 
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
  // ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER  BE LIABLE FOR ANY
  // DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  // (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  // LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  // ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  // 
  
  
  
  #pragma once
  
  #include "levin_base.h"
  #include "serializeble_struct_helper.h"
  #include "int-util.h"
  
  #undef SEVABIT_DEFAULT_LOG_CATEGORY
  #define SEVABIT_DEFAULT_LOG_CATEGORY "net"
  
  namespace epee
  {
  namespace levin
  {
  	template<class t_struct>
  	bool pack_struct_to_levin_message(const t_struct& t, std::string& buff, int command_id)
  	{
  		buff.resize(sizeof(levin::bucket_head));
  		levin::bucket_head& head = *(levin::bucket_head*)(&buff[0]);
  		head.m_signature = SWAP64LE(LEVIN_SIGNATURE);
  		head.m_cb = 0;
  		head.m_have_to_return_data = true;
  		head.m_command = SWAP32LE(command_id);
  		head.m_return_code = SWAP32LE(1);
  		head.m_reservedA = rand(); //probably some flags in future
  		head.m_reservedB = rand(); //probably some check summ in future
  
  		std::string buff_strg;
  		if(!StorageNamed::save_struct_as_storage_to_buff_t<t_struct, StorageNamed::DefaultStorageType>(t, buff_strg))
  			return false;
  		
  		head.m_cb = SWAP64LE(buff_strg.size());
  		buff.append(buff_strg);
  		return true;
  	}
  
  	
  	bool pack_data_to_levin_message(const std::string& data, std::string& buff, int command_id)
  	{
  		buff.resize(sizeof(levin::bucket_head));
  		levin::bucket_head& head = *(levin::bucket_head*)(&buff[0]);
  		head.m_signature = SWAP64LE(LEVIN_SIGNATURE);
  		head.m_cb = 0;
  		head.m_have_to_return_data = true;
  		head.m_command = SWAP32LE(command_id);
  		head.m_return_code = SWAP32LE(1);
  		head.m_reservedA = rand(); //probably some flags in future
  		head.m_reservedB = rand(); //probably some check summ in future
  
  		head.m_cb = SWAP64LE(data.size());
  		buff.append(data);
  		return true;
  	}
  
  	bool load_levin_data_from_levin_message(std::string& levin_data, const std::string& buff, int& command)
  	{
  		if(buff.size() < sizeof(levin::bucket_head) )
  		{
  			LOG_PRINT_L3("size of buff(" << buff.size() << ") is too small, at load_struct_from_levin_message");
  			return false;
  		}
  
  #if BYTE_ORDER == LITTLE_ENDIAN
  		levin::bucket_head &head = *(levin::bucket_head*)(&buff[0]);
  #else
  		levin::bucket_head head = *(levin::bucket_head*)(&buff[0]);
  		head.m_signature = SWAP64LE(head.m_signature);
  		head.m_cb = SWAP64LE(head.m_cb);
  		head.m_command = SWAP32LE(head.m_command);
  		head.m_return_code = SWAP32LE(head.m_return_code);
  		head.m_reservedA = SWAP32LE(head.m_reservedA);
  		head.m_reservedB = SWAP32LE(head.m_reservedB);
  #endif
  		if(head.m_signature != LEVIN_SIGNATURE)
  		{
  			LOG_PRINT_L3("Failed to read signature in levin message, at load_struct_from_levin_message");
  			return false;
  		}
  		if(head.m_cb != buff.size()-sizeof(levin::bucket_head))
  		{
  			LOG_PRINT_L3("sizes mismatch, at load_struct_from_levin_message");
  			return false;
  		}
  
  		//std::string buff_strg;
  		levin_data.assign(&buff[sizeof(levin::bucket_head)], buff.size()-sizeof(levin::bucket_head));
  		command = head.m_command;
  		return true;
  	}
  
  	template<class t_struct>
  	bool load_struct_from_levin_message(t_struct& t, const std::string& buff, int& command)
  	{
  		if(buff.size() < sizeof(levin::bucket_head) )
  		{
  			LOG_ERROR("size of buff(" << buff.size() << ") is too small, at load_struct_from_levin_message");
  			return false;
  		}
  		
  #if BYTE_ORDER == LITTLE_ENDIAN
  		levin::bucket_head &head = *(levin::bucket_head*)(&buff[0]);
  #else
  		levin::bucket_head head = *(levin::bucket_head*)(&buff[0]);
  		head.m_signature = SWAP64LE(head.m_signature);
  		head.m_cb = SWAP64LE(head.m_cb);
  		head.m_command = SWAP32LE(head.m_command);
  		head.m_return_code = SWAP32LE(head.m_return_code);
  		head.m_reservedA = SWAP32LE(head.m_reservedA);
  		head.m_reservedB = SWAP32LE(head.m_reservedB);
  #endif
  		if(head.m_signature != LEVIN_SIGNATURE)
  		{
  			LOG_ERROR("Failed to read signature in levin message, at load_struct_from_levin_message");
  			return false;
  		}
  		if(head.m_cb != buff.size()-sizeof(levin::bucket_head))
  		{
  			LOG_ERROR("sizes mismatch, at load_struct_from_levin_message");
  			return false;
  		}
  
  		std::string buff_strg;
  		buff_strg.assign(&buff[sizeof(levin::bucket_head)], buff.size()-sizeof(levin::bucket_head));
  
  		if(!StorageNamed::load_struct_from_storage_buff_t<t_struct, StorageNamed::DefaultStorageType>(t, buff_strg))
  		{
  			LOG_ERROR("Failed to read storage, at load_struct_from_levin_message");
  			return false;
  		}
  		command = head.m_command;
  		return true;
  	}
  }
  }
  