chartdata_input_stream.h

/******************************************************************************
 *
 * Project:  OpenCPN
 * Purpose:  Support XZ compressed charts
 * Author:   Sean D'Epagnier
 *
 ***************************************************************************
 *   Copyright (C) 2016 by David S. Register                               *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program 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 General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,  USA.             *
 ***************************************************************************
 *
 */
 
#include "config.h"
#include <wx/ffile.h>
 
#ifdef OCPN_USE_LZMA
#include <lzma.h>
 
// this implements a non-seekable input stream of xz compressed file
class wxCompressedFFileInputStream : public wxInputStream {
public:
  wxCompressedFFileInputStream(const wxString &fileName);
  virtual ~wxCompressedFFileInputStream();
 
  virtual bool IsOk() const {
    return wxStreamBase::IsOk() && m_file->IsOpened();
  }
  bool IsSeekable() const { return false; }
 
protected:
  size_t OnSysRead(void *buffer, size_t size);
  wxFileOffset OnSysSeek(wxFileOffset pos, wxSeekMode mode);
  wxFileOffset OnSysTell() const;
 
  wxFFile *m_file;
  lzma_stream strm;
 
private:
  void init_lzma();
 
  uint8_t inbuf[BUFSIZ];
 
  wxDECLARE_NO_COPY_CLASS(wxCompressedFFileInputStream);
};
 
// non-seekable stream for either non-compressed or compressed files
class ChartDataNonSeekableInputStream : public wxInputStream {
public:
  ChartDataNonSeekableInputStream(const wxString &fileName);
  virtual ~ChartDataNonSeekableInputStream();
 
  virtual bool IsOk() const { return m_stream->IsOk(); }
  bool IsSeekable() const { return false; }
 
protected:
  size_t OnSysRead(void *buffer, size_t size);
  wxFileOffset OnSysSeek(wxFileOffset pos, wxSeekMode mode);
  wxFileOffset OnSysTell() const;
 
private:
  wxInputStream *m_stream;
 
  wxDECLARE_NO_COPY_CLASS(ChartDataNonSeekableInputStream);
};
 
// seekable stream for either non-compressed or compressed files
// it must decompress the file to a temporary file to make it seekable
class ChartDataInputStream : public wxInputStream {
public:
  ChartDataInputStream(const wxString &fileName);
  virtual ~ChartDataInputStream();
 
  virtual bool IsOk() const { return m_stream->IsOk(); }
  bool IsSeekable() const { return m_stream->IsSeekable(); }
 
  wxString TempFileName() const { return m_tempfilename; }
 
protected:
  size_t OnSysRead(void *buffer, size_t size);
  wxFileOffset OnSysSeek(wxFileOffset pos, wxSeekMode mode);
  wxFileOffset OnSysTell() const;
 
private:
  wxString m_tempfilename;
  wxInputStream *m_stream;
 
  wxDECLARE_NO_COPY_CLASS(ChartDataInputStream);
};
 
#else
 
typedef wxFFileInputStream ChartDataInputStream;
typedef wxFFileInputStream ChartDataNonSeekableInputStream;
 
#endif  // OCPN_USE_LZMA
 
bool DecompressXZFile(const wxString &input_path, const wxString &output_path);