c-file-ptr-stream.h

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////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2000-2025 The Octave Project Developers
//
// See the file COPYRIGHT.md in the top-level directory of this
// distribution or <https://octave.org/copyright/>.
//
// This file is part of Octave.
//
// Octave 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 3 of the License, or
// (at your option) any later version.
//
// Octave 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 Octave; see the file COPYING.  If not, see
// <https://www.gnu.org/licenses/>.
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////////////////////////////////////////////////////////////////////////
 
#if ! defined (octave_c_file_ptr_stream_h)
#define octave_c_file_ptr_stream_h 1
 
#include "octave-config.h"
 
#include <cstdio>
#include <istream>
 
#if defined (HAVE_ZLIB_H)
#  include <zlib.h>
#endif
 
OCTAVE_BEGIN_NAMESPACE(octave)
 
class c_file_ptr_buf : public std::streambuf
{
public:
 
  typedef std::streambuf::int_type int_type;
 
  typedef int (*close_fcn) (FILE *);
 
  FILE * stdiofile () { return m_f; }
 
  c_file_ptr_buf () = delete;
 
  c_file_ptr_buf (FILE *f, close_fcn cf = file_close)
    : std::streambuf (), m_f (f), m_cf (cf)
  { }
 
  OCTAVE_DISABLE_COPY_MOVE (c_file_ptr_buf)
 
  ~c_file_ptr_buf ();
 
  int_type overflow (int_type);
 
  int_type underflow () { return underflow_common (false); }
 
  int_type uflow () { return underflow_common (true); }
 
  int_type pbackfail (int_type);
 
  std::streamsize xsputn (const char *, std::streamsize);
 
  std::streamsize xsgetn (char *, std::streamsize);
 
  std::streampos seekoff (std::streamoff, std::ios::seekdir,
                          std::ios::openmode = std::ios::in | std::ios::out);
 
  std::streampos seekpos (std::streampos,
                          std::ios::openmode = std::ios::in | std::ios::out);
 
  int sync ();
 
  int flush ();
 
  int buf_close ();
 
  int file_number () const { return m_f ? fileno (m_f) : -1; }
 
  int seek (off_t offset, int origin);
 
  off_t tell ();
 
  void clear () { if (m_f) clearerr (m_f); }
 
  static int file_close (FILE *m_f);
 
protected:
 
  FILE *m_f;
 
  close_fcn m_cf;
 
private:
 
  int_type underflow_common (bool);
};
 
// FIXME: the following three classes could probably share some code...
 
template <typename STREAM_T, typename FILE_T, typename BUF_T>
class c_file_ptr_stream : public STREAM_T
{
public:
 
  c_file_ptr_stream () = delete;
 
  c_file_ptr_stream (FILE_T m_f,
                     typename BUF_T::close_fcn m_cf = BUF_T::file_close)
    : STREAM_T (nullptr), m_buf (new BUF_T (m_f, m_cf))
  { STREAM_T::init (m_buf); }
 
  OCTAVE_DISABLE_COPY_MOVE (c_file_ptr_stream)
 
  ~c_file_ptr_stream () { delete m_buf; m_buf = nullptr; }
 
  BUF_T * rdbuf () { return m_buf; }
 
  void stream_close () { if (m_buf) m_buf->buf_close (); }
 
  int seek (off_t offset, int origin)
  { return m_buf ? m_buf->seek (offset, origin) : -1; }
 
  off_t tell () { return m_buf ? m_buf->tell () : -1; }
 
  void clear () { if (m_buf) m_buf->clear (); STREAM_T::clear (); }
 
private:
 
  BUF_T *m_buf;
};
 
typedef c_file_ptr_stream<std::istream, FILE *, c_file_ptr_buf>
  i_c_file_ptr_stream;
typedef c_file_ptr_stream<std::ostream, FILE *, c_file_ptr_buf>
  o_c_file_ptr_stream;
typedef c_file_ptr_stream<std::iostream, FILE *, c_file_ptr_buf>
  io_c_file_ptr_stream;
 
 
#if defined (HAVE_ZLIB)
 
class c_zfile_ptr_buf : public std::streambuf
{
public:
 
  typedef std::streambuf::int_type int_type;
 
  typedef int (*close_fcn) (gzFile);
 
  gzFile stdiofile () { return m_f; }
 
  c_zfile_ptr_buf () = delete;
 
  c_zfile_ptr_buf (gzFile f, close_fcn cf = file_close)
    : std::streambuf (), m_f (f), m_cf (cf)
  { }
 
  OCTAVE_DISABLE_COPY_MOVE (c_zfile_ptr_buf)
 
  ~c_zfile_ptr_buf ();
 
  int_type overflow (int_type);
 
  int_type underflow () { return underflow_common (false); }
 
  int_type uflow () { return underflow_common (true); }
 
  int_type pbackfail (int_type);
 
  std::streamsize xsputn (const char *, std::streamsize);
 
  std::streamsize xsgetn (char *, std::streamsize);
 
  std::streampos seekoff (std::streamoff, std::ios::seekdir,
                          std::ios::openmode = std::ios::in | std::ios::out);
 
  std::streampos seekpos (std::streampos,
                          std::ios::openmode = std::ios::in | std::ios::out);
 
  int sync ();
 
  int flush ();
 
  int buf_close ();
 
  int file_number () const { return -1; }
 
  int seek (off_t offset, int origin)
  { return m_f ? gzseek (m_f, offset, origin) >= 0 : -1; }
 
  off_t tell () { return m_f ? gztell (m_f) : -1; }
 
  void clear () { if (m_f) gzclearerr (m_f); }
 
  static int file_close (gzFile m_f) { return ::gzclose (m_f); }
 
protected:
 
  gzFile m_f;
 
  close_fcn m_cf;
 
private:
 
  int_type underflow_common (bool);
};
 
typedef c_file_ptr_stream<std::istream, gzFile, c_zfile_ptr_buf>
  i_c_zfile_ptr_stream;
typedef c_file_ptr_stream<std::ostream, gzFile, c_zfile_ptr_buf>
  o_c_zfile_ptr_stream;
typedef c_file_ptr_stream<std::iostream, gzFile, c_zfile_ptr_buf>
  io_c_zfile_ptr_stream;
 
#endif
 
OCTAVE_END_NAMESPACE(octave)
 
#endif