monero/contrib/epee/include/net/levin_helper.h

// Copyright (c) 2014, The Monero Project
// 
// All rights reserved.
// 
// Redistribution and use in source and binary forms, with or without modification, are
// permitted provided that the following conditions are met:
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// 1. Redistributions of source code must retain the above copyright notice, this list of
//    conditions and the following disclaimer.
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// 2. 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.
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// 3. Neither the name of the copyright holder 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
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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// Parts of this file are originally copyright (c) 2006-2013, Andrey N. Sabelnikov

#pragma once

#include "levin_base.h"
#include "serializeble_struct_helper.h"

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 = LEVIN_SIGNATURE;
		head.m_cb = 0;
		head.m_have_to_return_data = true;
		head.m_command = command_id;
		head.m_return_code = 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 = 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 = LEVIN_SIGNATURE;
		head.m_cb = 0;
		head.m_have_to_return_data = true;
		head.m_command = command_id;
		head.m_return_code = 1;
		head.m_reservedA = rand(); //probably some flags in future
		head.m_reservedB = rand(); //probably some check summ in future

		head.m_cb = 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;
		}

		levin::bucket_head& head = *(levin::bucket_head*)(&buff[0]);
		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 missmatch, 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;
		}
		
		levin::bucket_head& head = *(levin::bucket_head*)(&buff[0]);
		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 missmatch, 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;
	}
}
}