gzip.cc

Go to the documentation of this file.

/*

Copyright (C) 2016-2018 Carnë Draug

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/>.

*/

//! @file gzip.cc
//! Octave interface to the compression and uncompression libraries.
//!
//! This was originally implemented as an m file which directly called
//! bzip2 and gzip applications.  This may look simpler but causes some
//! issues (see bug #43431) because we have no control over the output
//! file:
//!
//!   - created file is always in the same directory as the original file;
//!   - automatically skip files that already have gz/bz2/etc extension;
//!   - some older versions lack the --keep option.
//!
//! In addition, because system() does not have a method that allows
//! passing a list of arguments, there is the issue of having to escape
//! filenames.
//!
//! A solution is to pipe file contents into the applications instead of
//! filenames.  However, that solution causes:
//!
//!   # missing file header with original file information;
//!   # implementing ourselves the recursive transversion of directories;
//!   # do the above in a m file which will be slow;
//!   # popen2 is frail on windows.

#if defined (HAVE_CONFIG_H)
#  include "config.h"
#endif

#include <cstdio>
#include <cstring>

#include <functional>
#include <list>
#include <stdexcept>
#include <string>

#include "Array.h"
#include "dir-ops.h"
#include "file-ops.h"
#include "file-stat.h"
#include "glob-match.h"
#include "oct-env.h"
#include "str-vec.h"

#include "Cell.h"
#include "defun-dld.h"
#include "defun-int.h"
#include "errwarn.h"
#include "ov.h"
#include "ovl.h"

#if defined (HAVE_BZLIB_H)
#  include <bzlib.h>
#endif

#if defined (HAVE_ZLIB_H)
#  include <zlib.h>
#endif

namespace octave
{
  //! RIIA wrapper for std::FILE*.
  //!
  //! If error handling is available for failing to close the file, use
  //! the close method which throws.
  //!
  //! If the file has been closed, fp is set to nullptr.  Remember that
  //! behavior is undefined if the value of the pointer stream is used
  //! after fclose.

  class CFile
  {
  public:

    CFile (void) = delete;

    CFile (const std::string& path, const std::string& mode)
      : m_fp (std::fopen (path.c_str (), mode.c_str ()))
    {
      if (! m_fp)
        throw std::runtime_error ("unable to open file");
    }

    CFile (const CFile&) = delete;

    CFile& operator = (const CFile&) = delete;

    ~CFile (void)
    {
      if (m_fp)
        std::fclose (m_fp);
    }

    void close (void)
    {
      if (std::fclose (m_fp))
        throw std::runtime_error ("unable to close file");

      m_fp = nullptr;
    }

    std::FILE *m_fp;
  };

#if defined (HAVE_BZ2)

  class bz2
  {
  public:

    static const constexpr char *extension = ".bz2";

    static void zip (const std::string& source_path,
                     const std::string& dest_path)
    {
      bz2::zipper z (source_path, dest_path);
      z.deflate ();
      z.close ();
    }

  private:

    class zipper
    {
    public:

      zipper (void) = delete;

      zipper (const std::string& source_path, const std::string& dest_path)
        : m_status (BZ_OK), m_source (source_path, "rb"),
          m_dest (dest_path, "wb"),
          m_bz (BZ2_bzWriteOpen (&m_status, m_dest.m_fp, 9, 0, 30))
      {
        if (m_status != BZ_OK)
          throw std::runtime_error ("failed to open bzip2 stream");
      }

      zipper (const zipper&) = delete;

      zipper& operator = (const zipper&) = delete;

      ~zipper (void)
      {
        if (m_bz != nullptr)
          BZ2_bzWriteClose (&m_status, m_bz, 1, nullptr, nullptr);
      }

      void deflate (void)
      {
        const std::size_t buf_len = 8192;
        char buf[buf_len];
        std::size_t n_read;
        while ((n_read = std::fread (buf, sizeof (buf[0]), buf_len, m_source.m_fp)) != 0)
          {
            if (std::ferror (m_source.m_fp))
              throw std::runtime_error ("failed to read from source file");
            BZ2_bzWrite (&m_status, m_bz, buf, n_read);
            if (m_status == BZ_IO_ERROR)
              throw std::runtime_error ("failed to write or compress");
          }
        if (std::ferror (m_source.m_fp))
          throw std::runtime_error ("failed to read from source file");
      }

      void close (void)
      {
        int abandon = (m_status == BZ_IO_ERROR) ? 1 : 0;
        BZ2_bzWriteClose (&m_status, m_bz, abandon, nullptr, nullptr);
        if (m_status != BZ_OK)
          throw std::runtime_error ("failed to close bzip2 stream");
        m_bz = nullptr;

        // We have no error handling for failing to close source, let
        // the destructor close it.
        m_dest.close ();
      }

    private:

      int m_status;
      CFile m_source;
      CFile m_dest;
      BZFILE *m_bz;
    };
  };

#endif

  // Note about zlib and gzip
  //
  // gzip is a format for compressed single files.  zlib is a format
  // designed for in-memory and communication channel applications.
  // gzip uses the same format internally for the compressed data but
  // has different headers and trailers.
  //
  // zlib is also a library but gzip is not.  Very old versions of zlib do
  // not include functions to create useful gzip headers and trailers:
  //
  //      Note that you cannot specify special gzip header contents (e.g.
  //      a file name or modification date), nor will inflate tell you what
  //      was in the gzip header. If you need to customize the header or
  //      see what's in it, you can use the raw deflate and inflate
  //      operations and the crc32() function and roll your own gzip
  //      encoding and decoding. Read the gzip RFC 1952 for details of the
  //      header and trailer format.
  //                                                          zlib FAQ
  //
  // Recent versions (on which we are already dependent) have deflateInit2()
  // to do it.  We still need to get the right metadata for the header
  // ourselves though.
  //
  // The header is defined in RFC #1952
  // GZIP file format specification version 4.3


#if defined (HAVE_Z)

  class gz
  {
  public:

    static const constexpr char *extension = ".gz";

    static void zip (const std::string& source_path,
                     const std::string& dest_path)
    {
      gz::zipper z (source_path, dest_path);
      z.deflate ();
      z.close ();
    }

  private:

    // Util class to get a non-const char*
    class uchar_array
    {
    public:

      // Bytef is a typedef for unsigned char
      unsigned char *p;

      uchar_array (void) = delete;

      uchar_array (const std::string& str)
      {
        p = new Bytef[str.length () + 1];
        std::strcpy (reinterpret_cast<char *> (p), str.c_str ());
      }

      uchar_array (const uchar_array&) = delete;

      uchar_array& operator = (const uchar_array&) = delete;

      ~uchar_array (void) { delete[] p; }
    };

    class gzip_header : public gz_header
    {
    public:

      gzip_header (void) = delete;

      gzip_header (const std::string& source_path)
        : m_basename (sys::env::base_pathname (source_path))
      {
        const sys::file_stat source_stat (source_path);
        if (! source_stat)
          throw std::runtime_error ("unable to stat source file");

        // time_t may be a signed int in which case it will be a
        // positive number so it is safe to uLong.  Or is it?  Can
        // unix_time really never be negative?
        time = uLong (source_stat.mtime ().unix_time ());

        //  If FNAME is set, an original file name is present,
        //  terminated by a zero byte.  The name must consist of ISO
        //  8859-1 (LATIN-1) characters; on operating systems using
        //  EBCDIC or any other character set for file names, the name
        //  must be translated to the ISO LATIN-1 character set.  This
        //  is the original name of the file being compressed, with any
        //  directory components removed, and, if the file being
        //  compressed is on a file system with case insensitive names,
        //  forced to lower case.
        name = m_basename.p;

        // If we don't set it to Z_NULL, then it will set FCOMMENT (4th bit)
        // on the FLG byte, and then write {0, 3} comment.
        comment = Z_NULL;

        // Seems to already be the default but we are not taking chances.
        extra = Z_NULL;

        // We do not want a CRC for the header.  That would be only 2 more
        // bytes, and maybe it would be a good thing but we want to generate
        // gz files similar to the default gzip application.
        hcrc = 0;

        // OS (Operating System):
        //      0 - FAT filesystem (MS-DOS, OS/2, NT/Win32)
        //      1 - Amiga
        //      2 - VMS (or OpenVMS)
        //      3 - Unix
        //      4 - VM/CMS
        //      5 - Atari TOS
        //      6 - HPFS filesystem (OS/2, NT)
        //      7 - Macintosh
        //      8 - Z-System
        //      9 - CP/M
        //     10 - TOPS-20
        //     11 - NTFS filesystem (NT)
        //     12 - QDOS
        //     13 - Acorn RISCOS
        //    255 - unknown
        //
        // The list is problematic because it mixes OS and filesystem.  It
        // also does not specify whether filesystem relates to source or
        // destination file.

#if defined (__WIN32__)
        // Or should it be 11?
        os = 0;
#elif defined (__APPLE__)
        os = 7;
#else
        // Unix by default?
        os = 3;
#endif
      }

      gzip_header (const gzip_header&) = delete;

      gzip_header& operator = (const gzip_header&) = delete;

      ~gzip_header (void) = default;

    private:

      // This must be kept for gz_header.name
      uchar_array m_basename;
    };

    class zipper
    {
    public:

      zipper (void) = delete;

      zipper (const std::string& source_path, const std::string& dest_path)
        : m_source (source_path, "rb"), m_dest (dest_path, "wb"),
          m_header (source_path), m_strm (new z_stream)
      {
        m_strm->zalloc = Z_NULL;
        m_strm->zfree = Z_NULL;
        m_strm->opaque = Z_NULL;
      }

      zipper (const zipper&) = delete;

      zipper& operator = (const zipper&) = delete;

      ~zipper (void)
      {
        if (m_strm)
          deflateEnd (m_strm);
        delete m_strm;
      }

      void deflate (void)
      {
        // int deflateInit2 (z_streamp m_strm,
        //                   int  level,      // compression level (default is 8)
        //                   int  method,
        //                   int  windowBits, // 15 (default) + 16 (gzip format)
        //                   int  memLevel,   // memory usage (default is 8)
        //                   int  strategy);
        int status = deflateInit2 (m_strm, 8, Z_DEFLATED, 31, 8,
                                   Z_DEFAULT_STRATEGY);
        if (status != Z_OK)
          throw std::runtime_error ("failed to open zlib stream");

        deflateSetHeader (m_strm, &m_header);

        const std::size_t buf_len = 8192;
        unsigned char buf_in[buf_len];
        unsigned char buf_out[buf_len];

        int flush;

        do
          {
            m_strm->avail_in = std::fread (buf_in, sizeof (buf_in[0]),
                                           buf_len, m_source.m_fp);

            if (std::ferror (m_source.m_fp))
              throw std::runtime_error ("failed to read source file");

            m_strm->next_in = buf_in;
            flush = (std::feof (m_source.m_fp) ? Z_FINISH : Z_NO_FLUSH);

            // If deflate returns Z_OK and with zero avail_out, it must be
            // called again after making room in the output buffer because
            // there might be more output pending.
            do
              {
                m_strm->avail_out = buf_len;
                m_strm->next_out = buf_out;
                status = ::deflate (m_strm, flush);
                if (status == Z_STREAM_ERROR)
                  throw std::runtime_error ("failed to deflate");

                std::fwrite (buf_out, sizeof (buf_out[0]),
                             buf_len - m_strm->avail_out, m_dest.m_fp);
                if (std::ferror (m_dest.m_fp))
                  throw std::runtime_error ("failed to write file");
              }
            while (m_strm->avail_out == 0);

            if (m_strm->avail_in != 0)
              throw std::runtime_error ("failed to write file");

          } while (flush != Z_FINISH);

        if (status != Z_STREAM_END)
          throw std::runtime_error ("failed to write file");
      }

      void close (void)
      {
        if (deflateEnd (m_strm) != Z_OK)
          throw std::runtime_error ("failed to close zlib stream");
        m_strm = nullptr;

        // We have no error handling for failing to close source, let
        // the destructor close it.
        m_dest.close ();
      }

    private:

      CFile m_source;
      CFile m_dest;
      gzip_header m_header;
      z_stream *m_strm;
    };
  };

#endif


  template<typename X>
  string_vector
  xzip (const Array<std::string>& source_patterns,
        const std::function<std::string(const std::string&)>& mk_dest_path)
  {
    std::list<std::string> dest_paths;

    std::function<void(const std::string&)> walk;
    walk = [&walk, &mk_dest_path, &dest_paths] (const std::string& path) -> void
    {
      const sys::file_stat fs (path);
      // is_dir and is_reg will return false if failed to stat.
      if (fs.is_dir ())
        {
          sys::dir_entry dir (path);
          if (dir)
            {
              // Collect the whole list of filenames first, before recursion
              // to avoid issues with infinite loop if the action generates
              // files in the same directory (highly likely).
              string_vector dirlist = dir.read ();
              for (octave_idx_type i = 0; i < dirlist.numel (); i++)
                if (dirlist(i) != "." && dirlist(i) != "..")
                  walk (sys::file_ops::concat (path, dirlist(i)));
            }
          // Note that we skip any problem with directories.
        }
      else if (fs.is_reg ())
        {
          const std::string dest_path = mk_dest_path (path);
          try
            {
              X::zip (path, dest_path);
            }
          catch (...)
            {
              // Error "handling" is not including filename on the output list.
              // Also remove created file which maybe was not even created
              // in the first place.  Note that it is possible for the file
              // to exist in the first place and for X::zip to not have
              // clobber it yet but we remove it anyway by design.
              sys::unlink (dest_path);
              return;
            }
          dest_paths.push_front (dest_path);
        }
      // Skip all other file types and errors.
      return;
    };

    for (octave_idx_type i = 0; i < source_patterns.numel (); i++)
      {
        const glob_match pattern (sys::file_ops::tilde_expand (source_patterns(i)));
        const string_vector filepaths = pattern.glob ();
        for (octave_idx_type j = 0; j < filepaths.numel (); j++)
          walk (filepaths(j));
      }
    return string_vector (dest_paths);
  }


  template<typename X>
  string_vector
  xzip (const Array<std::string>& source_patterns)
  {
    const std::string ext = X::extension;
    const std::function<std::string(const std::string&)> mk_dest_path
      = [&ext] (const std::string& source_path) -> std::string
      {
        return source_path + ext;
      };
    return xzip<X> (source_patterns, mk_dest_path);
  }

  template<typename X>
  string_vector
  xzip (const Array<std::string>& source_patterns, const std::string& out_dir)
  {
    const std::string ext = X::extension;
    const std::function<std::string(const std::string&)> mk_dest_path
      = [&out_dir, &ext] (const std::string& source_path) -> std::string
      {
        const std::string basename = sys::env::base_pathname (source_path);
        return sys::file_ops::concat (out_dir, basename + ext);
      };

    // We don't care if mkdir fails.  Maybe it failed because it already
    // exists, or maybe it can't bre created.  If the first, then there's
    // nothing to do, if the later, then it will be handled later.  Any
    // is to be handled by not listing files in the output.
    sys::mkdir (out_dir, 0777);
    return xzip<X> (source_patterns, mk_dest_path);
  }

  template<typename X>
  static octave_value_list
  xzip (const std::string& func_name, const octave_value_list& args)
  {
    const octave_idx_type nargin = args.length ();
    if (nargin < 1 || nargin > 2)
      print_usage ();

    const Array<std::string> source_patterns
      = args(0).xcellstr_value ("%s: FILES must be a character array or cellstr",
                                func_name.c_str ());
    if (nargin == 1)
      return octave_value (Cell (xzip<X> (source_patterns)));
    else // nargin == 2
      {
        const std::string out_dir = args(1).string_value ();
        return octave_value (Cell (xzip<X> (source_patterns, out_dir)));
      }
  }
}

DEFUN_DLD (gzip, args, ,
           doc: /* -*- texinfo -*-
@deftypefn  {} {@var{filelist} =} gzip (@var{files})
@deftypefnx {} {@var{filelist} =} gzip (@var{files}, @var{dir})
Compress the list of files and directories specified in @var{files}.

@var{files} is a character array or cell array of strings.  Shell wildcards
in the filename such as @samp{*} or @samp{?} are accepted and expanded.
Each file is compressed separately and a new file with a @file{".gz"}
extension is created.  The original files are not modified, but existing
compressed files will be silently overwritten.  If a directory is
specified then @code{gzip} recursively compresses all files in the
directory.

If @var{dir} is defined the compressed files are placed in this directory,
rather than the original directory where the uncompressed file resides.
Note that this does not replicate a directory tree in @var{dir} which may
lead to files overwriting each other if there are multiple files with the
same name.

If @var{dir} does not exist it is created.

The optional output @var{filelist} is a list of the compressed files.
@seealso{gunzip, unpack, bzip2, zip, tar}
@end deftypefn */)
{
#if defined (HAVE_Z)

  return octave::xzip<octave::gz> ("gzip", args);

#else

  octave_unused_parameter (args);

  err_disabled_feature ("gzip", "gzip");

#endif
}

/*
%!error gzip ()
%!error gzip ("1", "2", "3")
%!error <FILES must be a character array or cellstr|was unavailable or disabled> gzip (1)
*/

DEFUN_DLD (bzip2, args, ,
           doc: /* -*- texinfo -*-
@deftypefn  {} {@var{filelist} =} bzip2 (@var{files})
@deftypefnx {} {@var{filelist} =} bzip2 (@var{files}, @var{dir})
Compress the list of files specified in @var{files}.

@var{files} is a character array or cell array of strings.  Shell wildcards
in the filename such as @samp{*} or @samp{?} are accepted and expanded.
Each file is compressed separately and a new file with a @file{".bz2"}
extension is created.  The original files are not modified, but existing
compressed files will be silently overwritten.

If @var{dir} is defined the compressed files are placed in this directory,
rather than the original directory where the uncompressed file resides.
Note that this does not replicate a directory tree in @var{dir} which may
lead to files overwriting each other if there are multiple files with the
same name.

If @var{dir} does not exist it is created.

The optional output @var{filelist} is a list of the compressed files.
@seealso{bunzip2, unpack, gzip, zip, tar}
@end deftypefn */)
{
#if defined (HAVE_BZ2)

  return octave::xzip<octave::bz2> ("bzip2", args);

#else

  octave_unused_parameter (args);

  err_disabled_feature ("bzip2", "bzip2");

#endif
}

// Tests for both gzip/bzip2 and gunzip/bunzip2
/*

## Takes a single argument, a function handle for the test.  This other
## function must accept two arguments, a directory for the tests, and
## a cell array with zip function, unzip function, and file extension.

%!function run_test_function (test_function)
%!  enabled_zippers = struct ("zip", {}, "unzip", {}, "ext", {});
%!  if (__octave_config_info__ ().build_features.BZ2)
%!    enabled_zippers(end+1).zip = @bzip2;
%!    enabled_zippers(end).unzip = @bunzip2;
%!    enabled_zippers(end).ext = ".bz2";
%!  endif
%!  if (__octave_config_info__ ().build_features.Z)
%!    enabled_zippers(end+1).zip = @gzip;
%!    enabled_zippers(end).unzip = @gunzip;
%!    enabled_zippers(end).ext = ".gz";
%!  endif
%!
%!  for z = enabled_zippers
%!    test_dir = tempname ();
%!    if (! mkdir (test_dir))
%!      error ("unable to create directory for tests");
%!    endif
%!    unwind_protect
%!      test_function (test_dir, z)
%!    unwind_protect_cleanup
%!      confirm_recursive_rmdir (false, "local");
%!      rmdir (test_dir, "s");
%!    end_unwind_protect
%!  endfor
%!endfunction

%!function create_file (fpath, data)
%!  fid = fopen (fpath, "wb");
%!  if (fid < 0)
%!    error ("unable to open file for writing");
%!  endif
%!  if (fwrite (fid, data, class (data)) != numel (data))
%!    error ("unable to write to file");
%!  endif
%!  if (fflush (fid) || fclose (fid))
%!    error ("unable to flush or close file");
%!  endif
%!endfunction

%!function unlink_or_error (filepath)
%!  [err, msg] = unlink (filepath);
%!  if (err)
%!    error ("unable to remove file required for the test");
%!  endif
%!endfunction

## Test with large files because of varied buffer size
%!function test_large_file (test_dir, z)
%!  test_file = tempname (test_dir);
%!  create_file (test_file, rand (500000, 1));
%!  md5 = hash ("md5", fileread (test_file));
%!
%!  z_file = [test_file z.ext];
%!  z_filelist = z.zip (test_file);
%!  assert (z_filelist, {z_file})
%!
%!  unlink_or_error (test_file);
%!  uz_filelist = z.unzip (z_file);
%!  assert (uz_filelist, {test_file})
%!
%!  assert (hash ("md5", fileread (test_file)), md5)
%!endfunction
%!test run_test_function (@test_large_file)

## Test that xzipped files are rexzipped (hits bug #48597, #48598)
%!function test_z_z (test_dir, z)
%!  ori_file = tempname (test_dir);
%!  create_file (ori_file, rand (100, 1));
%!  md5_ori = hash ("md5", fileread (ori_file));
%!
%!  z_file = [ori_file z.ext];
%!  z_filelist = z.zip (ori_file);
%!  assert (z_filelist, {z_file}) # check output
%!  assert (exist (z_file), 2) # confirm file exists
%!  assert (exist (ori_file), 2) # and did not remove original file
%!
%!  unlink_or_error (ori_file);
%!  uz_filelist = z.unzip (z_file);
%!  assert (uz_filelist, {ori_file}) # bug #48598
%!  assert (hash ("md5", fileread (ori_file)), md5_ori)
%!  assert (exist (z_file), 2) # bug #48597
%!
%!  ## xzip should dutifully re-xzip files even if they already are zipped
%!  z_z_file = [z_file z.ext];
%!  z_z_filelist = z.zip (z_file);
%!  assert (z_z_filelist, {z_z_file}) # check output
%!  assert (exist (z_z_file), 2) # confirm file exists
%!  assert (exist (z_file), 2)
%!
%!  md5_z = hash ("md5", fileread (z_file));
%!  unlink_or_error (z_file);
%!  uz_z_filelist = z.unzip (z_z_file);
%!  assert (uz_z_filelist, {z_file}) # bug #48598
%!  assert (exist (z_z_file), 2) # bug #48597
%!  assert (hash ("md5", fileread (z_file)), md5_z)
%!endfunction
%!test <48597> run_test_function (@test_z_z)

%!function test_xzip_dir (test_dir, z) # bug #43431
%!  fpaths = fullfile (test_dir, {"test1", "test2", "test3"});
%!  md5s = cell (1, 3);
%!  for idx = 1:numel(fpaths)
%!    create_file (fpaths{idx}, rand (100, 1));
%!    md5s(idx) = hash ("md5", fileread (fpaths{idx}));
%!  endfor
%!
%!  test_dir = [test_dir filesep()];
%!
%!  z_files = strcat (fpaths, z.ext);
%!  z_filelist = z.zip (test_dir);
%!  assert (sort (z_filelist), z_files(:))
%!  for idx = 1:numel(fpaths)
%!    assert (exist (z_files{idx}), 2)
%!    unlink_or_error (fpaths{idx});
%!  endfor
%!
%!  ## only gunzip handles directory (bunzip2 should too though)
%!  if (z.unzip == @gunzip)
%!    uz_filelist = z.unzip (test_dir);
%!  else
%!    uz_filelist = cell (1, numel (z_filelist));
%!    for idx = 1:numel(z_filelist)
%!      uz_filelist(idx) = z.unzip (z_filelist{idx});
%!    endfor
%!  endif
%!  assert (sort (uz_filelist), fpaths(:)) # bug #48598
%!  for idx = 1:numel(fpaths)
%!    assert (hash ("md5", fileread (fpaths{idx})), md5s{idx})
%!  endfor
%!endfunction
%!test <48598> run_test_function (@test_xzip_dir)

%!function test_save_to_dir (test_dir, z)
%!  filename = "test-file";
%!  filepath = fullfile (test_dir, filename);
%!  create_file (filepath, rand (100, 1));
%!  md5 = hash ("md5", fileread (filepath));
%!
%!  ## test with existing and non-existing directory
%!  out_dirs = {tempname (test_dir), tempname (test_dir)};
%!  if (! mkdir (out_dirs{1}))
%!    error ("unable to create directory for test");
%!  endif
%!  unwind_protect
%!    for idx = 1:numel(out_dirs)
%!      out_dir = out_dirs{idx};
%!      uz_file = fullfile (out_dir, filename);
%!      z_file = [uz_file z.ext];
%!
%!      z_filelist = z.zip (filepath, out_dir);
%!      assert (z_filelist, {z_file})
%!      assert (exist (z_file, "file"), 2)
%!
%!      uz_filelist = z.unzip (z_file);
%!      assert (uz_filelist, {uz_file}) # bug #48598
%!
%!      assert (hash ("md5", fileread (uz_file)), md5)
%!    endfor
%!  unwind_protect_cleanup
%!    confirm_recursive_rmdir (false, "local");
%!    for idx = 1:numel(out_dirs)
%!      rmdir (out_dirs{idx}, "s");
%!    endfor
%!  end_unwind_protect
%!endfunction
%!test run_test_function (@test_save_to_dir)
*/