streamentry.cpp

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/*
  Zipios -- a small C++ library that provides easy access to .zip files.

  Copyright (C) 2000-2007  Thomas Sondergaard
  Copyright (c) 2015-2022  Made to Order Software Corp.  All Rights Reserved

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
*/

#include "zipios/streamentry.hpp"

#include "zipios/zipiosexceptions.hpp"

#include "zipios_common.hpp"

#include <fstream>
#include <zlib.h>


namespace zipios
{

StreamEntry::StreamEntry(
          std::istream & is
        , FilePath const & filename
        , std::string const & comment)
    : FileEntry(filename, comment)
    , f_istream(is)
{
    m_valid = static_cast<bool>(is);
    if(m_valid)
    {
        std::istream::pos_type const current(is.tellg());
        m_uncompressed_size = is.seekg(0, std::ios::end).tellg();
        is.seekg(current, std::ios::beg);

        m_unix_time = time(nullptr);
    }
}


FileEntry::pointer_t StreamEntry::clone() const
{
    return std::make_shared<StreamEntry>(*this);
}


StreamEntry::~StreamEntry()
{
}


bool StreamEntry::isEqual(FileEntry const & file_entry) const
{
    StreamEntry const * const se(dynamic_cast<StreamEntry const * const>(&file_entry));
    if(se == nullptr)
    {
        return false;
    }
    return FileEntry::isEqual(file_entry);
}


uint32_t StreamEntry::computeCRC32() const
{
    uint32_t result(crc32(0L, Z_NULL, 0));

    if(f_istream)
    {
        f_istream.seekg(0, std::ios::beg);
        for(;;)
        {
            Bytef buf[64 * 1024];
            f_istream.read(reinterpret_cast<char *>(buf), sizeof(buf));
            if(f_istream.gcount() == 0)
            {
                break;
            }
            result = crc32(result, buf, f_istream.gcount());
        }
    }

    return result;
}


std::istream & StreamEntry::getStream() const
{
    return f_istream;
}


} // zipios namespace

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