/*

Copyright (C) 1993-2019 John W. Eaton
Copyright (C) 2010 VZLU Prague

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/>.

*/

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

#include <cerrno>
#include <cstring>

#include <fstream>
#include <limits>
#include <ostream>
#include <string>

#include "dir-ops.h"
#include "file-ops.h"
#include "file-stat.h"
#include "lo-mappers.h"
#include "lo-utils.h"
#include "nanosleep-wrapper.h"
#include "oct-cmplx.h"
#include "oct-env.h"
#include "oct-locbuf.h"
#include "pathsearch.h"
#include "quit.h"
#include "str-vec.h"
#include "vasprintf-wrapper.h"

#include "Cell.h"
#include "defun.h"
#include "dirfns.h"
#include "error.h"
#include "errwarn.h"
#include "graphics.h"
#include "interpreter-private.h"
#include "interpreter.h"
#include "lex.h"
#include "load-path.h"
#include "oct-errno.h"
#include "oct-hist.h"
#include "ovl.h"
#include "ov-range.h"
#include "pager.h"
#include "parse.h"
#include "sysdep.h"
#include "unwind-prot.h"
#include "utils.h"
#include "variables.h"

namespace octave
{
  // Return TRUE if S is a valid identifier.

  bool valid_identifier (const char *s)
  {
    if (! s || ! (isalpha (*s) || *s == '_'))
      return false;

    while (*++s != '\0')
      if (! (isalnum (*s) || *s == '_'))
        return false;

    return true;
  }

  bool valid_identifier (const std::string& s)
  {
    return valid_identifier (s.c_str ());
  }
}

DEFUN (isvarname, args, ,
       doc: /* -*- texinfo -*-
@deftypefn {} {} isvarname (@var{name})
Return true if @var{name} is a valid variable name.

A valid variable name is composed of letters, digits, and underscores ("_"),
and the first character must not be a digit.
@seealso{iskeyword, exist, who}
@end deftypefn */)
{
  if (args.length () != 1)
    print_usage ();

  octave_value retval = false;

  if (args(0).is_string ())
    {
      std::string varname = args(0).string_value ();

      retval = (octave::valid_identifier (varname)
                && ! octave::iskeyword (varname));
    }

  return retval;
}

/*
%!assert (isvarname ("foo"), true)
%!assert (isvarname ("_foo"), true)
%!assert (isvarname ("_1"), true)
%!assert (isvarname ("1foo"), false)
%!assert (isvarname (""), false)
%!assert (isvarname (12), false)
%!assert (isvarname ("foo+bar"), false)

%!error isvarname ()
%!error isvarname ("foo", "bar")
*/

namespace octave
{
  // Return TRUE if F and G are both names for the same file.

  bool same_file (const std::string& f, const std::string& g)
  {
    return same_file_internal (f, g);
  }

  int almost_match (const std::string& std, const std::string& s,
                    int min_match_len, int case_sens)
  {
    int stdlen = std.length ();
    int slen = s.length ();

    return (slen <= stdlen
            && slen >= min_match_len
            && (case_sens
                ? (strncmp (std.c_str (), s.c_str (), slen) == 0)
                : (octave_strncasecmp (std.c_str (), s.c_str (), slen) == 0)));
  }

  // Ugh.

  int keyword_almost_match (const char * const *std, int *min_len,
                            const std::string& s,
                            int min_toks_to_match, int max_toks)
  {
    int status = 0;
    int tok_count = 0;
    int toks_matched = 0;

    if (s.empty () || max_toks < 1)
      return status;

    char *kw = strsave (s.c_str ());

    char *t = kw;
    while (*t != '\0')
      {
        if (*t == '\t')
          *t = ' ';
        t++;
      }

    char *beg = kw;
    while (*beg == ' ')
      beg++;

    if (*beg == '\0')
      return status;

    const char **to_match = new const char * [max_toks + 1];
    const char * const *s1 = std;
    const char **s2 = to_match;

    if (! s1 || ! s2)
      goto done;

    s2[tok_count] = beg;
    char *end;
    while ((end = strchr (beg, ' ')) != nullptr)
      {
        *end = '\0';
        beg = end + 1;

        while (*beg == ' ')
          beg++;

        if (*beg == '\0')
          break;

        tok_count++;
        if (tok_count >= max_toks)
          goto done;

        s2[tok_count] = beg;
      }
    s2[tok_count+1] = nullptr;

    s2 = to_match;

    for (;;)
      {
        if (! almost_match (*s1, *s2, min_len[toks_matched], 0))
          goto done;

        toks_matched++;

        s1++;
        s2++;

        if (! *s2)
          {
            status = (toks_matched >= min_toks_to_match);
            goto done;
          }

        if (! *s1)
          goto done;
      }

  done:

    delete [] kw;
    delete [] to_match;

    return status;
  }

  // See if the given file is in the path.

  std::string search_path_for_file (const std::string& path,
                                    const string_vector& names)
  {
    directory_path p (path);

    return sys::env::make_absolute (p.find_first_of (names.std_list ()));
  }

  // Find all locations of the given file in the path.

  string_vector search_path_for_all_files (const std::string& path,
                                           const string_vector& names)
  {
    directory_path p (path);

    string_vector sv = p.find_all_first_of (names.std_list ());

    octave_idx_type len = sv.numel ();

    for (octave_idx_type i = 0; i < len; i++)
      sv[i] = sys::env::make_absolute (sv[i]);

    return sv;
  }

  static string_vector make_absolute (const string_vector& sv)
  {
    octave_idx_type len = sv.numel ();

    string_vector retval (len);

    for (octave_idx_type i = 0; i < len; i++)
      retval[i] = sys::env::make_absolute (sv[i]);

    return retval;
  }
}

DEFMETHOD (file_in_loadpath, interp, args, ,
           doc: /* -*- texinfo -*-
@deftypefn  {} {@var{fname} =} file_in_loadpath (@var{file})
@deftypefnx {} {@var{fname} =} file_in_loadpath (@var{file}, "all")
Return the absolute name of @var{file} if it can be found in the list of
directories specified by @code{path}.

If no file is found, return an empty character string.

When @var{file} is already an absolute name, the name is checked against the
file system instead of Octave's loadpath.  In this case, if @var{file} exists
it will be returned in @var{fname}, otherwise an empty string is returned.

If the first argument is a cell array of strings, search each directory of
the loadpath for element of the cell array and return the first that
matches.

If the second optional argument @qcode{"all"} is supplied, return a cell
array containing the list of all files that have the same name in the path.
If no files are found, return an empty cell array.
@seealso{file_in_path, dir_in_loadpath, path}
@end deftypefn */)
{
  int nargin = args.length ();

  if (nargin < 1 || nargin > 2)
    print_usage ();

  string_vector names = args(0).xstring_vector_value ("file_in_loadpath: FILE argument must be a string");

  if (names.empty ())
    error ("file_in_loadpath: FILE argument must not be empty");

  octave::load_path& lp = interp.get_load_path ();

  if (nargin == 1)
    return ovl (octave::sys::env::make_absolute (lp.find_first_of (names)));
  else
    {
      std::string opt = args(1).xstring_value ("file_in_loadpath: optional second argument must be a string");

      if (opt != "all")
        error (R"(file_in_loadpath: "all" is only valid second argument)");

      return ovl (Cell (octave::make_absolute (lp.find_all_first_of (names))));
    }
}

/*
%!test
%! f = file_in_loadpath ("plot.m");
%! assert (ischar (f));
%! assert (! isempty (f));

%!test
%! f = file_in_loadpath ("$$probably_!! _not_&&_a_!! _file$$");
%! assert (f, "");

%!test
%! lst = file_in_loadpath ("$$probably_!! _not_&&_a_!! _file$$", "all");
%! assert (lst, {});

%!error file_in_loadpath ()
%!error file_in_loadpath ("foo", "bar", 1)
%!error file_in_loadpath ([])
%!error file_in_loadpath ("plot.m", "bar")
*/

DEFUN (file_in_path, args, ,
       doc: /* -*- texinfo -*-
@deftypefn  {} {} file_in_path (@var{path}, @var{file})
@deftypefnx {} {} file_in_path (@var{path}, @var{file}, "all")
Return the absolute name of @var{file} if it can be found in @var{path}.

The value of @var{path} should be a colon-separated list of directories in
the format described for @code{path}.  If no file is found, return an empty
character string.  For example:

@example
@group
file_in_path (EXEC_PATH, "sh")
     @result{} "/bin/sh"
@end group
@end example

If the second argument is a cell array of strings, search each directory of
the path for element of the cell array and return the first that matches.

If the third optional argument @qcode{"all"} is supplied, return a cell
array containing the list of all files that have the same name in the path.
If no files are found, return an empty cell array.
@seealso{file_in_loadpath, dir_in_loadpath, path}
@end deftypefn */)
{
  int nargin = args.length ();

  if (nargin < 2 || nargin > 3)
    print_usage ();

  std::string path = args(0).xstring_value ("file_in_path: PATH must be a string");

  string_vector names = args(1).xstring_vector_value ("file_in_path: FILE argument must be a string");

  if (names.empty ())
    error ("file_in_path: FILE argument must not be empty");

  if (nargin == 2)
    return ovl (octave::search_path_for_file (path, names));
  else
    {
      std::string opt = args(2).xstring_value ("file_in_path: optional third argument must be a string");

      if (opt != "all")
        error (R"(file_in_path: "all" is only valid third argument)");

      return ovl (Cell (octave::make_absolute (octave::search_path_for_all_files (path, names))));
    }
}

/*
%!test
%! f = file_in_path (path (), "plot.m");
%! assert (ischar (f));
%! assert (! isempty (f));

%!test
%! f = file_in_path (path (), "$$probably_!! _not_&&_a_!! _file$$");
%! assert (f, "");

%!test
%! lst = file_in_path (path (), "$$probably_!! _not_&&_a_!! _file$$", "all");
%! assert (lst, {});

%!error file_in_path ()
%!error file_in_path ("foo")
%!error file_in_path ("foo", "bar", "baz", 1)
%!error file_in_path ([])
%!error file_in_path (path (), [])
%!error file_in_path (path (), "plot.m", "bar")
*/

namespace octave
{
  std::string file_in_path (const std::string& name, const std::string& suffix)
  {
    std::string nm = name;

    if (! suffix.empty ())
      nm.append (suffix);

    load_path& lp = __get_load_path__ ("file_in_path");

    return sys::env::make_absolute (lp.find_file (nm));
  }

  std::string find_data_file_in_load_path  (const std::string& fcn,
                                            const std::string& file,
                                            bool require_regular_file)
  {
    std::string fname = file;

    if (! (sys::env::absolute_pathname (fname)
           || sys::env::rooted_relative_pathname (fname)))
      {
        // Load path will also search "." first, but we don't want to
        // issue a warning if the file is found in the current directory,
        // so do an explicit check for that.
        sys::file_stat fs (fname);

        bool local_file_ok
          = fs.exists () && (fs.is_reg () || ! require_regular_file);

        if (! local_file_ok)
          {
            load_path& lp = __get_load_path__ ("find_data_file_in_load_path");

            // Not directly found; search load path.
            std::string tmp = sys::env::make_absolute (lp.find_file (fname));

            if (! tmp.empty ())
              {
                warn_data_file_in_path (fcn, tmp);

                fname = tmp;
              }
          }
      }

    return fname;
  }

  // See if there is an function file in the path.
  // If so, return the full path to the file.

  std::string fcn_file_in_path (const std::string& name)
  {
    std::string retval;

    int len = name.length ();

    if (len > 0)
      {
        if (sys::env::absolute_pathname (name))
          {
            sys::file_stat fs (name);

            if (fs.exists () && ! fs.is_dir ())
              retval = name;
          }
        else if (len > 2 && name[len - 2] == '.' && name[len - 1] == 'm')
          {
            load_path& lp = __get_load_path__ ("fcn_file_in_path");

            retval = lp.find_fcn_file (name.substr (0, len-2));
          }
        else
          {
            std::string fname = name;
            size_t pos = name.find_first_of ('>');
            if (pos != std::string::npos)
              fname = name.substr (0, pos);

            load_path& lp = __get_load_path__ ("fcn_file_in_path");

            retval = lp.find_fcn_file (fname);
          }
      }

    return retval;
  }

  // See if there is a directory called "name" in the path and if it
  // contains a Contents.m file.  If so, return the full path to this file.

  std::string contents_file_in_path (const std::string& dir)
  {
    std::string retval;

    if (! dir.empty ())
      {
        load_path& lp = __get_load_path__ ("contents_in_file_path");

        std::string tcontents
          = sys::file_ops::concat (lp.find_dir (dir), "Contents.m");

        sys::file_stat fs (tcontents);

        if (fs.exists ())
          retval = sys::env::make_absolute (tcontents);
      }

    return retval;
  }

  // Replace backslash escapes in a string with the real values.

  std::string do_string_escapes (const std::string& s)
  {
    std::string retval;

    size_t i = 0;
    size_t j = 0;
    size_t len = s.length ();

    retval.resize (len);

    while (j < len)
      {
        if (s[j] == '\\' && j+1 < len)
          {
            switch (s[++j])
              {
              case 'a': // alarm
                retval[i] = '\a';
                break;

              case 'b': // backspace
                retval[i] = '\b';
                break;

              case 'f': // formfeed
                retval[i] = '\f';
                break;

              case 'n': // newline
                retval[i] = '\n';
                break;

              case 'r': // carriage return
                retval[i] = '\r';
                break;

              case 't': // horizontal tab
                retval[i] = '\t';
                break;

              case 'v': // vertical tab
                retval[i] = '\v';
                break;

              case '\\': // backslash
                retval[i] = '\\';
                break;

              case '\'': // quote
                retval[i] = '\'';
                break;

              case '"': // double quote
                retval[i] = '"';
                break;

              case '0':
              case '1':
              case '2':
              case '3':
              case '4':
              case '5':
              case '6':
              case '7': // octal input
                {
                  size_t k;
                  int tmpi = s[j] - '0';
                  for (k = j+1; k < std::min (j+3, len); k++)
                    {
                      int digit = s[k] - '0';
                      if (digit < 0 || digit > 7)
                        break;
                      tmpi <<= 3;
                      tmpi += digit;
                    }
                  retval[i] = tmpi;
                  j = k - 1;
                  break;
                }

              case 'x': // hex input
                {
                  size_t k;
                  int tmpi = 0;
                  for (k = j+1; k < std::min (j+3, len); k++)
                    {
                      if (! isxdigit (s[k]))
                        break;

                      tmpi <<= 4;
                      int digit = s[k];
                      if (digit >= 'a')
                        tmpi += digit - 'a' + 10;
                      else if (digit >= 'A')
                        tmpi += digit - 'A' + 10;
                      else
                        tmpi += digit - '0';
                    }

                  if (k == j+1)
                    warning (R"(malformed hex escape sequence '\x' -- converting to '\0')");

                  retval[i] = tmpi;
                  j = k - 1;
                  break;
                }

              default:
                warning (R"(unrecognized escape sequence '\%c' -- converting to '%c')", s[j], s[j]);
                retval[i] = s[j];
                break;
              }
          }
        else
          retval[i] = s[j];

        i++;
        j++;
      }

    retval.resize (i);

    return retval;
  }
}

DEFUN (do_string_escapes, args, ,
       doc: /* -*- texinfo -*-
@deftypefn {} {} do_string_escapes (@var{string})
Convert escape sequences in @var{string} to the characters they represent.

Escape sequences begin with a leading backslash
(@qcode{'@xbackslashchar{}'}) followed by 1--3 characters
(.e.g., @qcode{"@xbackslashchar{}n"} => newline).
@seealso{undo_string_escapes}
@end deftypefn */)
{
  if (args.length () != 1)
    print_usage ();

  std::string str = args(0).xstring_value ("do_string_escapes: STRING argument must be of type string");

  return ovl (octave::do_string_escapes (str));
}

/*
%!assert (do_string_escapes ('foo\nbar'), "foo\nbar")
%!assert (do_string_escapes ("foo\\nbar"), "foo\nbar")
%!assert (do_string_escapes ("foo\\nbar"), ["foo", char(10), "bar"])
%!assert ("foo\nbar", ["foo", char(10), "bar"])

%!assert (do_string_escapes ('\0\a\b\f\n\r\t\v'), "\0\a\b\f\n\r\t\v")
%!assert (do_string_escapes ("\\0\\a\\b\\f\\n\\r\\t\\v"), "\0\a\b\f\n\r\t\v")
%!assert (do_string_escapes ("\\0\\a\\b\\f\\n\\r\\t\\v"),
%!        char ([0, 7, 8, 12, 10, 13, 9, 11]))
%!assert ("\0\a\b\f\n\r\t\v", char ([0, 7, 8, 12, 10, 13, 9, 11]))

%!assert (do_string_escapes ('\\'), "\\")
%!assert (do_string_escapes ("\\\\"), "\\")
%!assert (do_string_escapes ("\\\\"), char (92))

%!assert (do_string_escapes ('\''single-quoted\'''), "'single-quoted'")
%!assert (do_string_escapes ("\\'single-quoted\\'"), "'single-quoted'")
%!assert (do_string_escapes ('\"double-quoted\"'), "\"double-quoted\"")
%!assert (do_string_escapes ("\\\"double-quoted\\\""), "\"double-quoted\"")

%!assert (do_string_escapes ('A\4B'), ["A" char(4) "B"])
%!assert (do_string_escapes ('A\45B'), ["A" char(37) "B"])
%!assert (do_string_escapes ('A\123B'), ["A" char(83) "B"])
%!assert (sprintf ('\117\143\164\141\166\145'), "Octave")

%!assert (do_string_escapes ('A\x4G'), ["A" char(4) "G"])
%!assert (do_string_escapes ('A\x4AG'), ["A" char(74) "G"])
%!assert (sprintf ('\x4f\x63\x74\x61\x76\x65'), "Octave")

%!error do_string_escapes ()
%!error do_string_escapes ("foo", "bar")
%!error <STRING argument> do_string_escapes (3)
%!warning <malformed hex escape sequence> do_string_escapes ('\xG');
%!warning <unrecognized escape sequence> do_string_escapes ('\G');
*/

namespace octave
{
  const char * undo_string_escape (char c)
  {
    if (! c)
      return "";

    switch (c)
      {
      case '\0':
        return R"(\0)";

      case '\a':
        return R"(\a)";

      case '\b': // backspace
        return R"(\b)";

      case '\f': // formfeed
        return R"(\f)";

      case '\n': // newline
        return R"(\n)";

      case '\r': // carriage return
        return R"(\r)";

      case '\t': // horizontal tab
        return R"(\t)";

      case '\v': // vertical tab
        return R"(\v)";

      case '\\': // backslash
        return R"(\\)";

      case '"': // double quote
        return R"(\")";

      default:
        {
          static char retval[2] {'\0', '\0'};

          retval[0] = c;
          return retval;
        }
      }
  }

  std::string undo_string_escapes (const std::string& s)
  {
    std::string retval;

    for (size_t i = 0; i < s.length (); i++)
      retval.append (undo_string_escape (s[i]));

    return retval;
  }
}

DEFUN (undo_string_escapes, args, ,
       doc: /* -*- texinfo -*-
@deftypefn {} {} undo_string_escapes (@var{s})
Convert special characters in strings back to their escaped forms.

For example, the expression

@example
bell = "\a";
@end example

@noindent
assigns the value of the alert character (control-g, ASCII code 7) to the
string variable @code{bell}.  If this string is printed, the system will
ring the terminal bell (if it is possible).  This is normally the desired
outcome.  However, sometimes it is useful to be able to print the original
representation of the string, with the special characters replaced by their
escape sequences.  For example,

@example
@group
octave:13> undo_string_escapes (bell)
ans = \a
@end group
@end example

@noindent
replaces the unprintable alert character with its printable representation.
@seealso{do_string_escapes}
@end deftypefn */)
{
  if (args.length () != 1)
    print_usage ();

  std::string str = args(0).xstring_value ("undo_string_escapes: S argument must be a string");

  return ovl (octave::undo_string_escapes (str));
}

/*
%!assert (undo_string_escapes ("foo\nbar"), 'foo\nbar')
%!assert (undo_string_escapes ("foo\nbar"), "foo\\nbar")
%!assert (undo_string_escapes (["foo", char(10), "bar"]), "foo\\nbar")

%!assert (undo_string_escapes ("\a\b\f\n\r\t\v"), '\a\b\f\n\r\t\v')
%!assert (undo_string_escapes ("\a\b\f\n\r\t\v"), "\\a\\b\\f\\n\\r\\t\\v")
%!assert (undo_string_escapes (char ([7, 8, 12, 10, 13, 9, 11])),
%!        "\\a\\b\\f\\n\\r\\t\\v")

%!assert (undo_string_escapes ("\\"), '\\')
%!assert (undo_string_escapes ("\\"), "\\\\")
%!assert (undo_string_escapes (char (92)), "\\\\")

%!assert (undo_string_escapes ("\"double-quoted\""), '\"double-quoted\"')
%!assert (undo_string_escapes ("\"double-quoted\""), "\\\"double-quoted\\\"")

%!error undo_string_escapes ()
%!error undo_string_escapes ("foo", "bar")
%!error undo_string_escapes (3)
*/

DEFUN (is_absolute_filename, args, ,
       doc: /* -*- texinfo -*-
@deftypefn {} {} is_absolute_filename (@var{file})
Return true if @var{file} is an absolute filename.
@seealso{is_rooted_relative_filename, make_absolute_filename, isfolder}
@end deftypefn */)
{
  if (args.length () != 1)
    print_usage ();

  return ovl (args(0).is_string ()
              && octave::sys::env::absolute_pathname (args(0).string_value ()));
}

/*
## FIXME: We need system-dependent tests here.

%!error is_absolute_filename ()
%!error is_absolute_filename ("foo", "bar")
*/

DEFUN (is_rooted_relative_filename, args, ,
       doc: /* -*- texinfo -*-
@deftypefn {} {} is_rooted_relative_filename (@var{file})
Return true if @var{file} is a rooted-relative filename.
@seealso{is_absolute_filename, make_absolute_filename, isfolder}
@end deftypefn */)
{
  if (args.length () != 1)
    print_usage ();

  return ovl (args(0).is_string ()
              && octave::sys::env::rooted_relative_pathname (args(0).string_value ()));
}

/*
## FIXME: We need system-dependent tests here.

%!error is_rooted_relative_filename ()
%!error is_rooted_relative_filename ("foo", "bar")
*/

DEFUN (make_absolute_filename, args, ,
       doc: /* -*- texinfo -*-
@deftypefn {} {} make_absolute_filename (@var{file})
Return the full name of @var{file} beginning from the root of the file
system.

No check is done for the existence of @var{file}.
@seealso{canonicalize_file_name, is_absolute_filename, is_rooted_relative_filename, isfolder}
@end deftypefn */)
{
  if (args.length () != 1)
    print_usage ();

  std::string nm = args(0).xstring_value ("make_absolute_filename: FILE argument must be a filename");

  return ovl (octave::sys::env::make_absolute (nm));
}

/*
## FIXME: We need system-dependent tests here.

%!error make_absolute_filename ()
%!error make_absolute_filename ("foo", "bar")
*/

DEFMETHOD (dir_in_loadpath, interp, args, ,
           doc: /* -*- texinfo -*-
@deftypefn  {} {@var{dirname} =} dir_in_loadpath (@var{dir})
@deftypefnx {} {@var{dirname} =} dir_in_loadpath (@var{dir}, "all")
Return the absolute name of the loadpath element matching @var{dir} if it can
be found in the list of directories specified by @code{path}.

If no match is found, return an empty character string.

The match is performed at the end of each path element.  For example, if
@var{dir} is @qcode{"foo/bar"}, it matches the path element
@nospell{@qcode{"/some/dir/foo/bar"}}, but not
@nospell{@qcode{"/some/dir/foo/bar/baz"}}
@nospell{@qcode{"/some/dir/allfoo/bar"}}.  When @var{dir} is an absolute name,
rather than just a path fragment, it is matched against the file system
instead of Octave's loadpath.  In this case, if @var{dir} exists it will be
returned in @var{dirname}, otherwise an empty string is returned.

If the optional second argument is supplied, return a cell array containing
all name matches rather than just the first.
@seealso{file_in_path, file_in_loadpath, path}
@end deftypefn */)
{
  int nargin = args.length ();

  if (nargin < 1 || nargin > 2)
    print_usage ();

  std::string dir;

  dir = args(0).xstring_value ("dir_in_loadpath: DIR must be a directory name");

  octave::load_path& lp = interp.get_load_path ();

  if (nargin == 1)
    return ovl (lp.find_dir (dir));
  else
    return ovl (Cell (lp.find_matching_dirs (dir)));
}

/*
%!test
%! f = dir_in_loadpath ("plot");
%! assert (ischar (f));
%! assert (! isempty (f));

%!test
%! f = dir_in_loadpath ("$$probably_!! _not_&&_a_!! _dir$$");
%! assert (f, "");

%!test
%! lst = dir_in_loadpath ("$$probably_!! _not_&&_a_!! _dir$$", "all");
%! assert (lst, {});

%!error dir_in_loadpath ()
%!error dir_in_loadpath ("foo", "bar", 1)
*/

DEFUNX ("errno", Ferrno, args, ,
        doc: /* -*- texinfo -*-
@deftypefn  {} {@var{err} =} errno ()
@deftypefnx {} {@var{err} =} errno (@var{val})
@deftypefnx {} {@var{err} =} errno (@var{name})
Query or set the system-dependent variable errno.

When called with no inputs, return the current value of errno.

When called with a numeric input @var{val}, set the current value of errno
to the specified value.  The previous value of errno is returned as @var{err}.

When called with a character string @var{name}, return the numeric value of
errno which corresponds to the specified error code.  If @var{name} is not
a recognized error code then -1 is returned.

@seealso{errno_list}
@end deftypefn */)
{
  int nargin = args.length ();

  if (nargin > 1)
    print_usage ();

  octave_value retval;

  if (nargin == 1)
    {
      if (args(0).is_string ())
        {
          std::string nm = args(0).string_value ();

          retval = octave_errno::lookup (nm);
        }
      else
        {
          int val = args(0).xint_value ("errno: argument must be string or integer");

          retval = octave_errno::set (val);
        }
    }
  else
    retval = octave_errno::get ();

  return retval;
}

/*
%!assert (isnumeric (errno ()))

%!test
%! lst = errno_list ();
%! fns = fieldnames (lst);
%! oldval = errno (fns{1});
%! assert (isnumeric (oldval));
%! errno (oldval);
%! newval = errno ();
%! assert (oldval, newval);

%!error errno ("foo", 1)
*/

DEFUN (errno_list, args, ,
       doc: /* -*- texinfo -*-
@deftypefn {} {} errno_list ()
Return a structure containing the system-dependent errno values.
@seealso{errno}
@end deftypefn */)
{
  if (args.length () != 0)
    print_usage ();

  return ovl (octave_errno::list ());
}

/*
%!assert (isstruct (errno_list ()))

%!error errno_list ("foo")
*/

namespace octave
{
  static void check_dimensions (octave_idx_type& nr, octave_idx_type& nc,
                                const char *warnfor)
  {
    if (nr < 0 || nc < 0)
      {
        warning_with_id ("Octave:neg-dim-as-zero",
                         "%s: converting negative dimension to zero", warnfor);

        nr = (nr < 0) ? 0 : nr;
        nc = (nc < 0) ? 0 : nc;
      }
  }

  void check_dimensions (dim_vector& dim, const char *warnfor)
  {
    bool neg = false;

    for (int i = 0; i < dim.ndims (); i++)
      {
        if (dim(i) < 0)
          {
            dim(i) = 0;
            neg = true;
          }
      }

    if (neg)
      warning_with_id ("Octave:neg-dim-as-zero",
                       "%s: converting negative dimension to zero", warnfor);
  }

  void get_dimensions (const octave_value& a, const char *warn_for,
                       dim_vector& dim)
  {
    // We support dimensions to be specified by any vector, even if it's a
    // vector of dimensions 0x1, 1x0, 1x1x0, or 1x1x6.  If the vector ends
    // up being empty, the final dimensions end up being 0x0.
    if (! a.dims ().isvector ())
      error ("%s (A): use %s (size (A)) instead", warn_for, warn_for);

    const Array<octave_idx_type> v = a.octave_idx_type_vector_value (true);
    const octave_idx_type n = v.numel ();

    dim.resize (n); // even if n < 2, resize sets it back to 2
    if (n == 0)
      {
        dim(0) = 0;
        dim(1) = 0;
      }
    else if (n == 1)
      {
        dim(0) = v(0);
        dim(1) = v(0);
      }
    else
      for (octave_idx_type i = 0; i < n; i++)
        dim(i) = v(i);

    check_dimensions (dim, warn_for);
  }

  void get_dimensions (const octave_value& a, const char *warn_for,
                       octave_idx_type& nr, octave_idx_type& nc)
  {
    if (a.is_scalar_type ())
      {
        nr = nc = a.idx_type_value (true);
      }
    else
      {
        nr = a.rows ();
        nc = a.columns ();

        if ((nr != 1 || nc != 2) && (nr != 2 || nc != 1))
          error ("%s (A): use %s (size (A)) instead", warn_for, warn_for);

        Array<octave_idx_type> v = a.octave_idx_type_vector_value (true);
        nr = v(0);
        nc = v(1);
      }

    check_dimensions (nr, nc, warn_for);
  }

  void get_dimensions (const octave_value& a, const octave_value& b,
                       const char *warn_for, octave_idx_type& nr,
                       octave_idx_type& nc)
  {
    nr = (a.isempty () ? 0 : a.idx_type_value (true));
    nc = (b.isempty () ? 0 : b.idx_type_value (true));

    check_dimensions (nr, nc, warn_for);
  }

  octave_idx_type dims_to_numel (const dim_vector& dims,
                                 const octave_value_list& idx_arg)
  {
    octave_idx_type retval;

    octave_idx_type len = idx_arg.length ();

    if (len == 0)
      retval = dims.numel ();
    else
      {
        const dim_vector dv = dims.redim (len);
        retval = 1;
        for (octave_idx_type i = 0; i < len; i++)
          {
            octave_value idxi = idx_arg(i);
            if (idxi.is_magic_colon ())
              retval *= dv(i);
            else if (idxi.isnumeric ())
              retval *= idxi.numel ();
            else
              {
                try
                  {
                    idx_vector jdx = idxi.index_vector ();

                    retval *= jdx.length (dv(i));
                  }
                catch (const index_exception& e)
                  {
                    std::string idx = e.idx ();
                    std::string msg = e.details ();

                    error ("dims_to_numel: Invalid IDX %s. %s",
                           idx.c_str (), msg.c_str ());
                  }
              }
          }
      }

    return retval;
  }

  Matrix identity_matrix (octave_idx_type nr, octave_idx_type nc)
  {
    Matrix m (nr, nc, 0.0);

    if (nr > 0 && nc > 0)
      {
        octave_idx_type n = std::min (nr, nc);

        for (octave_idx_type i = 0; i < n; i++)
          m (i, i) = 1.0;
      }

    return m;
  }

  FloatMatrix float_identity_matrix (octave_idx_type nr, octave_idx_type nc)
  {
    FloatMatrix m (nr, nc, 0.0);

    if (nr > 0 && nc > 0)
      {
        octave_idx_type n = std::min (nr, nc);

        for (octave_idx_type i = 0; i < n; i++)
          m (i, i) = 1.0;
      }

    return m;
  }

  size_t format (std::ostream& os, const char *fmt, ...)
  {
    size_t retval;

    va_list args;
    va_start (args, fmt);

    retval = vformat (os, fmt, args);

    va_end (args);

    return retval;
  }

  size_t vformat (std::ostream& os, const char *fmt, va_list args)
  {
    std::string s = vasprintf (fmt, args);

    os << s;

    return s.length ();
  }

  std::string vasprintf (const char *fmt, va_list args)
  {
    std::string retval;

    char *result;

    int status = octave_vasprintf_wrapper (&result, fmt, args);

    if (status >= 0)
      {
        retval = result;
        ::free (result);
      }

    return retval;
  }

  std::string asprintf (const char *fmt, ...)
  {
    std::string retval;

    va_list args;
    va_start (args, fmt);

    retval = vasprintf (fmt, args);

    va_end (args);

    return retval;
  }

  // FIXME: sleep is complicated because we want it to be interruptible.
  // With the way this program handles signals, the sleep system call
  // won't respond to SIGINT.  Maybe there is a better way than
  // breaking this up into multiple shorter intervals?

  void sleep (double seconds, bool do_graphics_events)
  {
    if (seconds <= 0)
      return;

    // Allow free access to graphics resources while the interpreter thread
    // is asleep
    if (do_graphics_events)
      gh_manager::unlock ();

    if (math::isinf (seconds))
      {
        // Wait for kbhit
        int c = -1;
        flush_stdout ();

        struct timespec one_tenth = { 0, 100000000 };

        while (c < 0)
          {
            octave_nanosleep_wrapper (&one_tenth, nullptr);

            octave_quit ();

            if (do_graphics_events)
              gh_manager::process_events ();

            c = kbhit (false);
          }
      }
    else
      {
        sys::time now;
        double end_time = now.double_value () + seconds;
        double remaining_time = seconds;

        // Split pause into 100 ms time steps to allow the execution of
        // graphics events and interrupts.
        struct timespec nano_laps = { 0, 100000000 };

        while (remaining_time > 0.1)
          {
            octave_quit ();

            if (do_graphics_events)
              {
                gh_manager::process_events ();

                now.stamp ();
                remaining_time = end_time - now.double_value ();

                if (remaining_time < 0.1)
                  break;
              }

            octave_nanosleep_wrapper (&nano_laps, nullptr);

            now.stamp ();
            remaining_time = end_time - now.double_value ();
          }

        if (remaining_time > 0.0)
          {
            nano_laps = { 0, static_cast<int> (remaining_time * 1e9) };
            octave_nanosleep_wrapper (&nano_laps, nullptr);
          }
      }
  }
}

DEFMETHOD (isindex, interp, args, ,
           doc: /* -*- texinfo -*-
@deftypefn  {} {} isindex (@var{ind})
@deftypefnx {} {} isindex (@var{ind}, @var{n})
Return true if @var{ind} is a valid index.

Valid indices are either positive integers (although possibly of real data
type), or logical arrays.

If present, @var{n} specifies the maximum extent of the dimension to be
indexed.  When possible the internal result is cached so that subsequent
indexing using @var{ind} will not perform the check again.

Implementation Note: Strings are first converted to double values before the
checks for valid indices are made.  Unless a string contains the NULL
character @nospell{"@xbackslashchar{}0"}, it will always be a valid index.
@end deftypefn */)
{
  int nargin = args.length ();

  if (nargin < 1 || nargin > 2)
    print_usage ();

  octave_idx_type n = 0;
  if (nargin == 2)
    n = args(1).idx_type_value ();

  octave_value retval;

  octave::error_system& es = interp.get_error_system ();

  octave::unwind_protect frame;

  frame.add_method (es, &octave::error_system::set_discard_error_messages,
                    es.discard_error_messages ());
  es.discard_error_messages (true);

  try
    {
      idx_vector idx = args(0).index_vector (true);

      if (nargin == 2)
        retval = idx.extent (n) <= n;
      else
        retval = true;
    }
  catch (const octave::execution_exception&)
    {
      octave::interpreter::recover_from_exception ();

      retval = false;
    }

  return retval;
}

/*
%!assert (isindex ([1, 2, 3]))
%!assert (isindex (1:3))
%!assert (isindex (1:3, 2), false)
%!assert (isindex ([1, 2, -3]), false)

%!error isindex ()
%!error isindex (1:3, 2, 3)
*/

namespace octave
{
  octave_value_list
  do_simple_cellfun (octave_value_list (*fun) (const octave_value_list&, int),
                     const char *fun_name, const octave_value_list& args,
                     int nargout)
  {
    octave_value_list new_args = args;
    octave_value_list retval;
    int nargin = args.length ();
    OCTAVE_LOCAL_BUFFER (bool, iscell, nargin);
    OCTAVE_LOCAL_BUFFER (Cell, cells, nargin);
    OCTAVE_LOCAL_BUFFER (Cell, rcells, nargout);

    const Cell *ccells = cells;

    octave_idx_type numel = 1;
    dim_vector dims (1, 1);

    for (int i = 0; i < nargin; i++)
      {
        octave_value arg = new_args(i);
        iscell[i] = arg.iscell ();
        if (iscell[i])
          {
            cells[i] = arg.cell_value ();
            octave_idx_type n = ccells[i].numel ();
            if (n == 1)
              {
                iscell[i] = false;
                new_args(i) = ccells[i](0);
              }
            else if (numel == 1)
              {
                numel = n;
                dims = ccells[i].dims ();
              }
            else if (dims != ccells[i].dims ())
              error ("%s: cell arguments must have matching sizes", fun_name);
          }
      }

    for (int i = 0; i < nargout; i++)
      rcells[i].clear (dims);

    for (octave_idx_type j = 0; j < numel; j++)
      {
        for (int i = 0; i < nargin; i++)
          if (iscell[i])
            new_args(i) = ccells[i](j);

        octave_quit ();

        const octave_value_list tmp = fun (new_args, nargout);

        if (tmp.length () < nargout)
          error ("%s: do_simple_cellfun: internal error", fun_name);

        for (int i = 0; i < nargout; i++)
          rcells[i](j) = tmp(i);
      }

    retval.resize (nargout);

    for (int i = 0; i < nargout; i++)
      retval(i) = rcells[i];

    return retval;
  }

  octave_value
  do_simple_cellfun (octave_value_list (*fun) (const octave_value_list&, int),
                     const char *fun_name, const octave_value_list& args)
  {
    octave_value retval;

    const octave_value_list tmp = do_simple_cellfun (fun, fun_name, args, 1);

    if (tmp.length () > 0)
      retval = tmp(0);

    return retval;
  }
}

DEFUN (isstudent, args, ,
       doc: /* -*- texinfo -*-
@deftypefn {} {} isstudent ()
Return true if running in the student edition of @sc{matlab}.

@code{isstudent} always returns false in Octave.
@seealso{false}
@end deftypefn */)
{
  if (args.length () != 0)
    print_usage ();

  return ovl (false);
}

/*
%!assert (isstudent (), false)

%!error isstudent (1)
*/

// Always define these functions.  The macro is intended to allow the
// declarations to be hidden, not so that Octave will not provide the
// functions if they are requested.

// #if defined (OCTAVE_USE_DEPRECATED_FUNCTIONS)

#include "ov.h"
#include "ovl.h"
#include "str-vec.h"

bool
valid_identifier (const char *s)
{
  return octave::valid_identifier (s);
}

bool
valid_identifier (const std::string& s)
{
  return octave::valid_identifier (s);
}

bool
same_file (const std::string& f, const std::string& g)
{
  return octave::same_file (f, g);
}

int
almost_match (const std::string& std, const std::string& s,
              int min_match_len, int case_sens)
{
  return octave::almost_match (std, s, min_match_len, case_sens);
}

int
keyword_almost_match (const char * const *std, int *min_len,
                      const std::string& s, int min_toks_to_match,
                      int max_toks)
{
  return octave::keyword_almost_match (std, min_len, s, min_toks_to_match,
                                       max_toks);
}

std::string
search_path_for_file (const std::string& path, const string_vector& names)
{
  return octave::search_path_for_file (path, names);
}

string_vector
search_path_for_all_files (const std::string& path, const string_vector& names)
{
  return octave::search_path_for_all_files (path, names);
}

std::string
file_in_path (const std::string& name, const std::string& suffix)
{
  return octave::file_in_path (name, suffix);
}

std::string
find_data_file_in_load_path  (const std::string& fcn, const std::string& file,
                              bool require_regular_file)
{
  return octave::find_data_file_in_load_path  (fcn, file, require_regular_file);
}

std::string
contents_file_in_path (const std::string& s)
{
  return octave::contents_file_in_path (s);
}

std::string
fcn_file_in_path (const std::string& s)
{
  return octave::fcn_file_in_path (s);
}

std::string
do_string_escapes (const std::string& s)
{
  return octave::do_string_escapes (s);
}

const char *
undo_string_escape (char c)
{
  return octave::undo_string_escape (c);
}

std::string
undo_string_escapes (const std::string& s)
{
  return octave::undo_string_escapes (s);
}

void
check_dimensions (dim_vector& dim, const char *warnfor)
{
  return octave::check_dimensions (dim, warnfor);
}

void
get_dimensions (const octave_value& a, const char *warn_for,
                dim_vector& dim)
{
  return octave::get_dimensions (a, warn_for, dim);
}

void
get_dimensions (const octave_value& a, const octave_value& b,
                const char *warn_for, octave_idx_type& nr,
                octave_idx_type& nc)
{
  return octave::get_dimensions (a, b, warn_for, nr, nc);
}

void
get_dimensions (const octave_value& a, const char *warn_for,
                octave_idx_type& nr, octave_idx_type& nc)
{
  return octave::get_dimensions (a, warn_for, nr, nc);
}

octave_idx_type
dims_to_numel (const dim_vector& dims, const octave_value_list& idx)
{
  return octave::dims_to_numel (dims, idx);
}

Matrix
identity_matrix (octave_idx_type nr, octave_idx_type nc)
{
  return octave::identity_matrix (nr, nc);
}

FloatMatrix
float_identity_matrix (octave_idx_type nr, octave_idx_type nc)
{
  return octave::float_identity_matrix (nr, nc);
}

size_t
octave_vformat (std::ostream& os, const char *fmt, va_list args)
{
  return octave::vformat (os, fmt, args);
}

std::string
octave_vasprintf (const char *fmt, va_list args)
{
  return octave::vasprintf (fmt, args);
}

void
octave_sleep (double seconds)
{
  octave::sleep (seconds);
}

octave_value_list
do_simple_cellfun (octave_value_list (*fun) (const octave_value_list&, int),
                   const char *fun_name, const octave_value_list& args,
                   int nargout)
{
  return octave::do_simple_cellfun (fun, fun_name, args, nargout);
}

octave_value
do_simple_cellfun (octave_value_list (*fun) (const octave_value_list&, int),
                   const char *fun_name, const octave_value_list& args)
{
  return octave::do_simple_cellfun (fun, fun_name, args);
}

// #endif