monero/contrib/epee/include/zlib_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:
// 
// 1. Redistributions of source code must retain the above copyright notice, this list of
//    conditions and the following disclaimer.
// 
// 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.
// 
// 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
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
// THE COPYRIGHT HOLDER OR CONTRIBUTORS 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.
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// Parts of this file are originally copyright (c) 2006-2013, Andrey N. Sabelnikov

#pragma once
extern "C" { 
#include "zlib/zlib.h"
}
#pragma comment(lib, "zlibstat.lib")

namespace epee 
{
namespace zlib_helper
{
	inline 
	bool pack(std::string& target){
		std::string result_packed_buff;

		z_stream    zstream = {0};
		int ret = deflateInit(&zstream, Z_DEFAULT_COMPRESSION);
		if(target.size())
		{

			
			result_packed_buff.resize(target.size()*2, 'X');

			zstream.next_in = (Bytef*)target.data();
			zstream.avail_in = (uInt)target.size();
			zstream.next_out = (Bytef*)result_packed_buff.data();
			zstream.avail_out = (uInt)result_packed_buff.size();

			ret = deflate(&zstream, Z_FINISH);
			CHECK_AND_ASSERT_MES(ret>=0, false, "Failed to deflate. err = " << ret);

			if(result_packed_buff.size() != zstream.avail_out)
				result_packed_buff.resize(result_packed_buff.size()-zstream.avail_out);

			
			result_packed_buff.erase(0, 2);
			target.swap(result_packed_buff);
		}

		deflateEnd(& zstream );
		return true;
	}

	inline bool unpack(std::string& target)
	{
		z_stream    zstream = {0};
		int ret = inflateInit(&zstream);//

		std::string decode_summary_buff;
		size_t	ungzip_buff_size = target.size() * 0x30;
		std::string current_decode_buff(ungzip_buff_size, 'X');

		while(target.size())
		{

			
			zstream.next_out = (Bytef*)current_decode_buff.data();
			zstream.avail_out = (uInt)ungzip_buff_size;

			int flag = Z_SYNC_FLUSH;
			
			static char dummy_head[2] =
			{
				0x8 + 0x7 * 0x10,
				(((0x8 + 0x7 * 0x10) * 0x100 + 30) / 31 * 31) & 0xFF,
			};
			zstream.next_in = (Bytef*) dummy_head;
			zstream.avail_in = sizeof(dummy_head);
			ret = inflate(&zstream, Z_NO_FLUSH);
			if (ret != Z_OK)
			{
				LOCAL_ASSERT(0);
				return false;
			}
			
			zstream.next_in = (Bytef*)target.data();
			zstream.avail_in = (uInt)target.size();

			ret = inflate(&zstream, Z_SYNC_FLUSH);
			if (ret != Z_OK && ret != Z_STREAM_END)
			{
				LOCAL_ASSERT(0);
				return false;
			}

			
			target.erase(0, target.size()-zstream.avail_in);

			
			if(ungzip_buff_size == zstream.avail_out)
			{
				LOG_ERROR("Can't unpack buffer");
				return false;
			}

			
			current_decode_buff.resize(ungzip_buff_size - zstream.avail_out);
			if(decode_summary_buff.size())
				decode_summary_buff += current_decode_buff;
			else
				current_decode_buff.swap(decode_summary_buff);

			current_decode_buff.resize(ungzip_buff_size);
		}

		inflateEnd(&zstream );

		decode_summary_buff.swap(target);
		return 1;
	}

};
}//namespace epee