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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.
//
#ifndef _GZIP_ENCODING_H_
#define _GZIP_ENCODING_H_
#include "net/http_client_base.h"
#include "zlib/zlib.h"
//#include "http.h"
namespace epee
{
namespace net_utils
{
class content_encoding_gzip: public i_sub_handler
{
public:
/*! \brief
* Function content_encoding_gzip : Constructor
*
*/
inline
content_encoding_gzip(i_target_handler* powner_filter, bool is_deflate_mode = false):m_powner_filter(powner_filter),
m_is_stream_ended(false),
m_is_deflate_mode(is_deflate_mode),
m_is_first_update_in(true)
{
memset(&m_zstream_in, 0, sizeof(m_zstream_in));
memset(&m_zstream_out, 0, sizeof(m_zstream_out));
int ret = 0;
if(is_deflate_mode)
{
ret = inflateInit(&m_zstream_in);
ret = deflateInit(&m_zstream_out, Z_DEFAULT_COMPRESSION);
}else
{
ret = inflateInit2(&m_zstream_in, 0x1F);
ret = deflateInit2(&m_zstream_out, Z_DEFAULT_COMPRESSION, Z_DEFLATED, 0x1F, 8, Z_DEFAULT_STRATEGY);
}
}
/*! \brief
* Function content_encoding_gzip : Destructor
*
*/
inline
~content_encoding_gzip()
{
inflateEnd(& m_zstream_in );
deflateEnd(& m_zstream_out );
}
/*! \brief
* Function update_in : Entry point for income data
*
*/
inline
virtual bool update_in( std::string& piece_of_transfer)
{
bool is_first_time_here = m_is_first_update_in;
m_is_first_update_in = false;
if(m_pre_decode.size())
m_pre_decode += piece_of_transfer;
else
m_pre_decode.swap(piece_of_transfer);
piece_of_transfer.clear();
std::string decode_summary_buff;
size_t ungzip_size = m_pre_decode.size() * 0x30;
std::string current_decode_buff(ungzip_size, 'X');
//Here the cycle is introduced where we unpack the buffer, the cycle is required
//because of the case where if after unpacking the data will exceed the awaited size, we will not halt with error
bool continue_unpacking = true;
bool first_step = true;
while(m_pre_decode.size() && continue_unpacking)
{
//fill buffers
m_zstream_in.next_in = (Bytef*)m_pre_decode.data();
m_zstream_in.avail_in = (uInt)m_pre_decode.size();
m_zstream_in.next_out = (Bytef*)current_decode_buff.data();
m_zstream_in.avail_out = (uInt)ungzip_size;
int flag = Z_SYNC_FLUSH;
int ret = inflate(&m_zstream_in, flag);
CHECK_AND_ASSERT_MES(ret>=0 || m_zstream_in.avail_out ||m_is_deflate_mode, false, "content_encoding_gzip::update_in() Failed to inflate. err = " << ret);
if(Z_STREAM_END == ret)
m_is_stream_ended = true;
else if(Z_DATA_ERROR == ret && is_first_time_here && m_is_deflate_mode&& first_step)
{
// some servers (notably Apache with mod_deflate) don't generate zlib headers
// insert a dummy header and try again
static char dummy_head[2] =
{
0x8 + 0x7 * 0x10,
(((0x8 + 0x7 * 0x10) * 0x100 + 30) / 31 * 31) & 0xFF,
};
inflateReset(&m_zstream_in);
m_zstream_in.next_in = (Bytef*) dummy_head;
m_zstream_in.avail_in = sizeof(dummy_head);
ret = inflate(&m_zstream_in, Z_NO_FLUSH);
if (ret != Z_OK)
{
LOCAL_ASSERT(0);
m_pre_decode.swap(piece_of_transfer);
return false;
}
m_zstream_in.next_in = (Bytef*)m_pre_decode.data();
m_zstream_in.avail_in = (uInt)m_pre_decode.size();
ret = inflate(&m_zstream_in, Z_NO_FLUSH);
if (ret != Z_OK)
{
LOCAL_ASSERT(0);
m_pre_decode.swap(piece_of_transfer);
return false;
}
}
//leave only unpacked part in the output buffer to start with it the next time
m_pre_decode.erase(0, m_pre_decode.size()-m_zstream_in.avail_in);
//if decoder gave nothing to return, then everything is ahead, now simply break
if(ungzip_size == m_zstream_in.avail_out)
break;
//decode_buff currently stores data parts that were unpacked, fix this size
current_decode_buff.resize(ungzip_size - m_zstream_in.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_size);
first_step = false;
}
//Process these data if required
bool res = true;
res = m_powner_filter->handle_target_data(decode_summary_buff);
return true;
}
/*! \brief
* Function stop : Entry point for stop signal and flushing cached data buffer.
*
*/
inline
virtual void stop(std::string& OUT collect_remains)
{
}
protected:
private:
/*! \brief
* Pointer to parent HTTP-parser
*/
i_target_handler* m_powner_filter;
/*! \brief
* ZLIB object for income stream
*/
z_stream m_zstream_in;
/*! \brief
* ZLIB object for outcome stream
*/
z_stream m_zstream_out;
/*! \brief
* Data that could not be unpacked immediately, left to wait for the next packet of data
*/
std::string m_pre_decode;
/*! \brief
* The data are accumulated for a package in the buffer to send the web client
*/
std::string m_pre_encode;
/*! \brief
* Signals that stream looks like ended
*/
bool m_is_stream_ended;
/*! \brief
* If this flag is set, income data is in HTTP-deflate mode
*/
bool m_is_deflate_mode;
/*! \brief
* Marks that it is a first data packet
*/
bool m_is_first_update_in;
};
}
}
#endif //_GZIP_ENCODING_H_
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