levin_helper.h

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// 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 ELECTRONEUM_DEFAULT_LOG_CATEGORY
#define ELECTRONEUM_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;
    }
}
}