CompressionStreams.hpp

Go to the documentation of this file.

/* 
 * CompressionStreams.hpp 
 *
 * This file is part of the Chemical Data Processing Toolkit
 *
 * Copyright (C) 2003 Thomas Seidel <thomas.seidel@univie.ac.at>
 *
 * 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 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; see the file COPYING. If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */
 
#ifndef CDPL_UTIL_COMPRESSIONSTREAMS_HPP
#define CDPL_UTIL_COMPRESSIONSTREAMS_HPP
 
#include <fstream>
 
#include <boost/iostreams/copy.hpp>
#include <boost/iostreams/filtering_stream.hpp>
#include <boost/iostreams/filter/gzip.hpp>
#include <boost/iostreams/filter/bzip2.hpp>
 
#include "CDPL/Util/FileRemover.hpp"
#include "CDPL/Util/FileFunctions.hpp"
 
 
namespace CDPL
{
 
    namespace Util
    {
 
        enum CompressionAlgo
        {
 
            GZIP,
            BZIP2
        };
 
        template <CompressionAlgo CompAlgo>
        struct CompressionAlgoTraits;
 
        template <>
        struct CompressionAlgoTraits<GZIP>
        {
 
            typedef boost::iostreams::gzip_decompressor DecompFilter;
            typedef boost::iostreams::gzip_compressor   CompFilter;
        };
 
        template <>
        struct CompressionAlgoTraits<BZIP2>
        {
 
            typedef boost::iostreams::bzip2_decompressor DecompFilter;
            typedef boost::iostreams::bzip2_compressor   CompFilter;
        };
 
        template <CompressionAlgo CompAlgo, typename StreamType>
        class CompressionStreamBase : public StreamType
        {
 
          public:
            typedef typename StreamType::char_type             char_type;
            typedef typename StreamType::traits_type           traits_type;
            typedef typename StreamType::int_type              int_type;
            typedef typename StreamType::pos_type              pos_type;
            typedef typename StreamType::off_type              off_type;
            typedef std::basic_istream<char_type, traits_type> IStreamType;
            typedef std::basic_ostream<char_type, traits_type> OStreamType;
 
            CompressionStreamBase();
 
          protected:
            virtual ~CompressionStreamBase() {}
 
            void closeTmpFile();
            void openTmpFile();
 
            void decompInput(IStreamType& is);
            void compOutput(OStreamType& os);
 
          private:
            typedef std::basic_filebuf<char_type, traits_type> FileBufType;
 
            FileBufType tmpFileBuf;
        };
 
        template <CompressionAlgo CompAlgo, typename CharT = char, typename TraitsT = std::char_traits<CharT> >
        class DecompressionIStream : public CompressionStreamBase<CompAlgo, std::basic_istream<CharT, TraitsT> >
        {
 
          public:
            typedef typename std::basic_istream<CharT, TraitsT> StreamType;
            typedef typename StreamType::char_type              char_type;
            typedef typename StreamType::traits_type            traits_type;
            typedef typename StreamType::int_type               int_type;
            typedef typename StreamType::pos_type               pos_type;
            typedef typename StreamType::off_type               off_type;
 
            DecompressionIStream();
            DecompressionIStream(StreamType& stream);
 
            void open(StreamType& stream);
            void close();
        };
 
        template <CompressionAlgo CompAlgo, typename CharT = char, typename TraitsT = std::char_traits<CharT> >
        class CompressionOStream : public CompressionStreamBase<CompAlgo, std::basic_ostream<CharT, TraitsT> >
        {
 
          public:
            typedef typename std::basic_ostream<CharT, TraitsT> StreamType;
            typedef typename StreamType::char_type              char_type;
            typedef typename StreamType::traits_type            traits_type;
            typedef typename StreamType::int_type               int_type;
            typedef typename StreamType::pos_type               pos_type;
            typedef typename StreamType::off_type               off_type;
 
            CompressionOStream();
            CompressionOStream(StreamType& stream);
 
            ~CompressionOStream();
 
            void open(StreamType& stream);
            void close();
 
          private:
            StreamType* stream;
            off_type    outPos;
        };
 
        template <CompressionAlgo CompAlgo, typename CharT = char, typename TraitsT = std::char_traits<CharT> >
        class CompressedIOStream : public CompressionStreamBase<CompAlgo, std::basic_iostream<CharT, TraitsT> >
        {
 
          public:
            typedef typename std::basic_iostream<CharT, TraitsT> StreamType;
            typedef typename StreamType::char_type               char_type;
            typedef typename StreamType::traits_type             traits_type;
            typedef typename StreamType::int_type                int_type;
            typedef typename StreamType::pos_type                pos_type;
            typedef typename StreamType::off_type                off_type;
 
            CompressedIOStream();
            CompressedIOStream(StreamType& stream);
 
            ~CompressedIOStream();
 
            void open(StreamType& stream);
            void close();
 
          private:
            StreamType* stream;
            off_type    outPos;
        };
 
        typedef DecompressionIStream<GZIP>  GZipIStream;
        typedef DecompressionIStream<BZIP2> BZip2IStream;
        typedef CompressionOStream<GZIP>    GZipOStream;
        typedef CompressionOStream<BZIP2>   BZip2OStream;
        typedef CompressedIOStream<GZIP>    GZipIOStream;
        typedef CompressedIOStream<BZIP2>   BZip2IOStream;
    } // namespace Util
} // namespace CDPL
 
 
// CompressionStreamBase Implementation
 
template <CDPL::Util::CompressionAlgo CompAlgo, typename StreamType>
CDPL::Util::CompressionStreamBase<CompAlgo, StreamType>::CompressionStreamBase():
    StreamType(&tmpFileBuf)
{}
 
template <CDPL::Util::CompressionAlgo CompAlgo, typename StreamType>
void CDPL::Util::CompressionStreamBase<CompAlgo, StreamType>::closeTmpFile()
{
    if (!tmpFileBuf.close())
        this->setstate(std::ios_base::failbit);
    else
        this->clear();
}
 
template <CDPL::Util::CompressionAlgo CompAlgo, typename StreamType>
void CDPL::Util::CompressionStreamBase<CompAlgo, StreamType>::openTmpFile()
{
    FileRemover tmp_file_rem(genCheckedTempFilePath());
 
    if (!tmpFileBuf.open(tmp_file_rem.getPath().c_str(),
                         std::ios_base::in | std::ios_base::out |
                             std::ios_base::trunc | std::ios_base::binary))
        this->setstate(std::ios_base::failbit);
    else
        this->clear(std::ios_base::goodbit);
}
 
template <CDPL::Util::CompressionAlgo CompAlgo, typename StreamType>
void CDPL::Util::CompressionStreamBase<CompAlgo, StreamType>::decompInput(IStreamType& is)
{
    off_type rpos = is.tellg();
 
    is.seekg(0, std::ios_base::end);
 
    off_type rend = is.tellg();
 
    if (!is.good()) {
        this->setstate(std::ios_base::failbit);
        return;
    }
 
    if (rpos == rend)
        return;
 
    is.seekg(rpos);
 
    boost::iostreams::filtering_stream<boost::iostreams::input, char_type, traits_type> fs;
 
    fs.push(typename CDPL::Util::CompressionAlgoTraits<CompAlgo>::DecompFilter());
    fs.push(is);
 
    boost::iostreams::copy(fs, *this->rdbuf());
 
    if (this->tmpFileBuf.pubseekpos(0, std::ios_base::in | std::ios_base::out) != 0)
        this->setstate(std::ios_base::failbit);
 
    this->setstate(is.rdstate() | fs.rdstate());
}
 
template <CDPL::Util::CompressionAlgo CompAlgo, typename StreamType>
void CDPL::Util::CompressionStreamBase<CompAlgo, StreamType>::compOutput(OStreamType& os)
{
    if (tmpFileBuf.pubseekpos(0, std::ios_base::in) != 0) {
        this->setstate(std::ios_base::failbit);
        return;
    }
 
    boost::iostreams::filtering_stream<boost::iostreams::output, char_type, traits_type> fs;
 
    fs.push(typename CDPL::Util::CompressionAlgoTraits<CompAlgo>::CompFilter());
    fs.push(os);
 
    boost::iostreams::copy(*this->rdbuf(), fs);
 
    this->setstate(os.rdstate() | fs.rdstate());
}
 
// DecompressionIStream Implementation
 
template <CDPL::Util::CompressionAlgo CompAlgo, typename CharT, typename TraitsT>
CDPL::Util::DecompressionIStream<CompAlgo, CharT, TraitsT>::DecompressionIStream()
{}
 
template <CDPL::Util::CompressionAlgo CompAlgo, typename CharT, typename TraitsT>
CDPL::Util::DecompressionIStream<CompAlgo, CharT, TraitsT>::DecompressionIStream(StreamType& stream)
{
    open(stream);
}
 
template <CDPL::Util::CompressionAlgo CompAlgo, typename CharT, typename TraitsT>
void CDPL::Util::DecompressionIStream<CompAlgo, CharT, TraitsT>::open(StreamType& stream)
{
    this->openTmpFile();
 
    if (this->good())
        this->decompInput(stream);
}
 
template <CDPL::Util::CompressionAlgo CompAlgo, typename CharT, typename TraitsT>
void CDPL::Util::DecompressionIStream<CompAlgo, CharT, TraitsT>::close()
{
    this->closeTmpFile();
}
 
// CompressionOStream Implementation
 
template <CDPL::Util::CompressionAlgo CompAlgo, typename CharT, typename TraitsT>
CDPL::Util::CompressionOStream<CompAlgo, CharT, TraitsT>::CompressionOStream():
    stream(0)
{}
 
template <CDPL::Util::CompressionAlgo CompAlgo, typename CharT, typename TraitsT>
CDPL::Util::CompressionOStream<CompAlgo, CharT, TraitsT>::CompressionOStream(StreamType& stream):
    stream(0)
{
    open(stream);
}
 
template <CDPL::Util::CompressionAlgo CompAlgo, typename CharT, typename TraitsT>
CDPL::Util::CompressionOStream<CompAlgo, CharT, TraitsT>::~CompressionOStream()
{
    if (stream) {
        try {
            stream->seekp(outPos);
            this->compOutput(*stream);
        } catch (...) {}
    }
}
 
template <CDPL::Util::CompressionAlgo CompAlgo, typename CharT, typename TraitsT>
void CDPL::Util::CompressionOStream<CompAlgo, CharT, TraitsT>::open(StreamType& stream)
{
    this->openTmpFile();
 
    if (!this->good())
        return;
 
    outPos = stream.tellp();
    this->setstate(stream.rdstate());
 
    if (this->good())
        this->stream = &stream;
}
 
template <CDPL::Util::CompressionAlgo CompAlgo, typename CharT, typename TraitsT>
void CDPL::Util::CompressionOStream<CompAlgo, CharT, TraitsT>::close()
{
    if (stream) {
        stream->seekp(outPos);
        this->compOutput(*stream);
 
        if (!this->good())
            return;
 
        stream = 0;
    }
 
    this->closeTmpFile();
}
 
// CompressedIOStream Implementation
 
template <CDPL::Util::CompressionAlgo CompAlgo, typename CharT, typename TraitsT>
CDPL::Util::CompressedIOStream<CompAlgo, CharT, TraitsT>::CompressedIOStream():
    stream(0)
{}
 
template <CDPL::Util::CompressionAlgo CompAlgo, typename CharT, typename TraitsT>
CDPL::Util::CompressedIOStream<CompAlgo, CharT, TraitsT>::CompressedIOStream(StreamType& stream):
    stream(0)
{
    open(stream);
}
 
template <CDPL::Util::CompressionAlgo CompAlgo, typename CharT, typename TraitsT>
CDPL::Util::CompressedIOStream<CompAlgo, CharT, TraitsT>::~CompressedIOStream()
{
    if (stream) {
        try {
            stream->seekp(outPos);
            this->compOutput(*stream);
        } catch (...) {}
    }
}
 
template <CDPL::Util::CompressionAlgo CompAlgo, typename CharT, typename TraitsT>
void CDPL::Util::CompressedIOStream<CompAlgo, CharT, TraitsT>::open(StreamType& stream)
{
    this->openTmpFile();
 
    if (!this->good())
        return;
 
    outPos = stream.tellp();
    this->setstate(stream.rdstate());
 
    if (!this->good())
        return;
 
    this->decompInput(stream);
 
    if (this->good())
        this->stream = &stream;
}
 
template <CDPL::Util::CompressionAlgo CompAlgo, typename CharT, typename TraitsT>
void CDPL::Util::CompressedIOStream<CompAlgo, CharT, TraitsT>::close()
{
    if (stream) {
        stream->seekp(outPos);
        this->compOutput(*stream);
 
        if (!this->good())
            return;
 
        stream = 0;
    }
 
    this->closeTmpFile();
}
 
#endif // CDPL_UTIL_COMPRESSIONSTREAMS_HPP