
(********************************************************************)
(*                                                                  *)
(*  osfiles.s7i   Functions to handle operating system files        *)
(*  Copyright (C) 1989 - 2017, 2019  Thomas Mertes                  *)
(*                                                                  *)
(*  This file is part of the Seed7 Runtime Library.                 *)
(*                                                                  *)
(*  The Seed7 Runtime 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 2.1 of the License, or (at your      *)
(*  option) any later version.                                      *)
(*                                                                  *)
(*  The Seed7 Runtime 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 program; if not, write to the    *)
(*  Free Software Foundation, Inc., 51 Franklin Street,             *)
(*  Fifth Floor, Boston, MA  02110-1301, USA.                       *)
(*                                                                  *)
(********************************************************************)


include "enable_io.s7i";
include "time.s7i";
include "bigint.s7i";
include "filesys.s7i";


const proc: GET_ATIME (in string: filePath, inout integer: year,
    inout integer: month, inout integer: day, inout integer: hour,
    inout integer: minute, inout integer: second, inout integer: micro_second,
    inout integer: timeZone, inout boolean: daylightSavingTime)  is action "CMD_GET_ATIME";

const proc: GET_CTIME (in string: filePath, inout integer: year,
    inout integer: month, inout integer: day, inout integer: hour,
    inout integer: minute, inout integer: second, inout integer: micro_second,
    inout integer: timeZone, inout boolean: daylightSavingTime)  is action "CMD_GET_CTIME";

const proc: GET_MTIME (in string: filePath, inout integer: year,
    inout integer: month, inout integer: day, inout integer: hour,
    inout integer: minute, inout integer: second, inout integer: micro_second,
    inout integer: timeZone, inout boolean: daylightSavingTime)  is action "CMD_GET_MTIME";

const proc: SET_ATIME (in string: filePath, in integer: year, in integer: month,
    in integer: day, in integer: hour, in integer: minute, in integer: second,
    in integer: micro_second, in integer: timeZone)              is action "CMD_SET_ATIME";

const proc: SET_MTIME (in string: filePath, in integer: year, in integer: month,
    in integer: day, in integer: hour, in integer: minute, in integer: second,
    in integer: micro_second, in integer: timeZone)              is action "CMD_SET_MTIME";


(**
 *  Determine the filenames in a directory.
 *  The files "." and ".." are left out from the result.
 *  Note that the function returns only the filenames.
 *  Additional information must be obtained with other calls.
 *  @return a string-array containing the filenames in the directory.
 *  @exception MEMORY_ERROR Not enough memory to convert ''dirPath''
 *             to the system path type or not enough memory to
 *             represent the result ''string array''.
 *  @exception RANGE_ERROR ''dirPath'' does not use the standard path
 *             representation or it cannot be converted to the system
 *             path type.
 *  @exception FILE_ERROR A system function returns an error.
 *)
const func array string: readDir (in string: dirPath)        is action "CMD_LS";


(**
 *  Determine the type of a file.
 *  The function does follow symbolic links. When the chain of
 *  symbolic links is too long the function returns ''FILE_SYMLINK''.
 *  When a symbolic link refers to a place where the permission
 *  is denied the function returns ''FILE_SYMLINK''.
 *  A return value of ''FILE_ABSENT'' does not imply that a file
 *  with this name can be created, since missing directories and
 *  illegal file names cause also ''FILE_ABSENT''.
 *  @return the type of the file.
 *  @exception MEMORY_ERROR Not enough memory to convert ''filePath''
 *             to the system path type.
 *  @exception RANGE_ERROR ''filePath'' does not use the standard path
 *             representation.
 *  @exception FILE_ERROR The system function returns an error other
 *             than ENOENT, ENOTDIR or ENAMETOOLONG.
 *)
const func fileType: fileType (in string: filePath)          is action "CMD_FILETYPE";


(**
 *  Determine the type of a file.
 *  The function does not follow symbolic links. Therefore it may
 *  return ''FILE_SYMLINK''. A return value of ''FILE_ABSENT'' does
 *  not imply that a file with this name can be created, since missing
 *  directories and illegal file names cause also ''FILE_ABSENT''.
 *  @return the type of the file.
 *  @exception MEMORY_ERROR Not enough memory to convert ''filePath''
 *             to the system path type.
 *  @exception RANGE_ERROR ''filePath'' does not use the standard path
 *             representation.
 *  @exception FILE_ERROR The system function returns an error other
 *             than ENOENT, ENOTDIR or ENAMETOOLONG.
 *)
const func fileType: fileTypeSL (in string: filePath)        is action "CMD_FILETYPE_SL";


(**
 *  Determine the file mode (permissions) of a file.
 *  @return the file mode.
 *  @exception MEMORY_ERROR Not enough memory to convert ''filePath''
 *             to the system path type.
 *  @exception RANGE_ERROR ''filePath'' does not use the standard path
 *             representation or it cannot be converted to the system
 *             path type.
 *  @exception FILE_ERROR A system function returns an error.
 *)
const func fileMode: fileMode (in string: filePath)          is action "CMD_FILEMODE";


(**
 *  Change the file mode (permissions) of a file.
 *  @exception MEMORY_ERROR Not enough memory to convert ''filePath''
 *             to the system path type.
 *  @exception RANGE_ERROR ''filePath'' does not use the standard path
 *             representation or it cannot be converted to the system
 *             path type.
 *  @exception FILE_ERROR A system function returns an error.
 *)
const proc: setFileMode (in string: filePath, in fileMode: mode) is action "CMD_SET_FILEMODE";


(**
 *  Determine the size of a file.
 *  The file size is measured in bytes.
 *  For directories a size of 0 is returned.
 *  @return the size of the file.
 *  @exception MEMORY_ERROR Not enough memory to convert ''filePath''
 *             to the system path type.
 *  @exception RANGE_ERROR ''filePath'' does not use the standard path
 *             representation or it cannot be converted to the system
 *             path type.
 *  @exception RANGE_ERROR The file size is not representable as integer.
 *  @exception FILE_ERROR It was not possible to determine the file size.
 *)
const func integer: fileSize (in string: filePath)           is action "CMD_FILESIZE";


(**
 *  Determine the size of a file.
 *  The file size is measured in bytes.
 *  For directories a size of 0 is returned.
 *  @return the size of the file.
 *  @exception MEMORY_ERROR Not enough memory to convert ''filePath''
 *             to the system path type.
 *  @exception RANGE_ERROR ''filePath'' does not use the standard path
 *             representation or it cannot be converted to the system
 *             path type.
 *  @exception FILE_ERROR It was not possible to determine the file size.
 *)
const func bigInteger: bigFileSize (in string: filePath)     is action "CMD_BIG_FILESIZE";


(**
 *  Determine the access time of a file.
 *  @return the access time of the file.
 *  @exception MEMORY_ERROR Not enough memory to convert ''filePath''
 *             to the system path type.
 *  @exception RANGE_ERROR ''filePath'' does not use the standard path
 *             representation or it cannot be converted to the system
 *             path type.
 *  @exception FILE_ERROR A system function returns an error.
 *)
const func time: getATime (in string: filePath) is func
  result
    var time: accessTime is time.value;
  begin
    GET_ATIME(filePath, accessTime.year, accessTime.month, accessTime.day,
        accessTime.hour, accessTime.minute, accessTime.second,
        accessTime.micro_second, accessTime.timeZone,
        accessTime.daylightSavingTime);
  end func;


(**
 *  Determine the change time of a file.
 *  @return the change time of the file.
 *  @exception MEMORY_ERROR Not enough memory to convert ''filePath''
 *             to the system path type.
 *  @exception RANGE_ERROR ''filePath'' does not use the standard path
 *             representation or it cannot be converted to the system
 *             path type.
 *  @exception FILE_ERROR A system function returns an error.
 *)
const func time: getCTime (in string: filePath) is func
  result
    var time: changeTime is time.value;
  begin
    GET_CTIME(filePath, changeTime.year, changeTime.month, changeTime.day,
        changeTime.hour, changeTime.minute, changeTime.second,
        changeTime.micro_second, changeTime.timeZone,
        changeTime.daylightSavingTime);
  end func;


(**
 *  Determine the modification time of a file.
 *  @return the modification time of the file.
 *  @exception MEMORY_ERROR Not enough memory to convert ''filePath''
 *             to the system path type.
 *  @exception RANGE_ERROR ''filePath'' does not use the standard path
 *             representation or it cannot be converted to the system
 *             path type.
 *  @exception FILE_ERROR A system function returns an error.
 *)
const func time: getMTime (in string: filePath) is func
  result
    var time: modificationTime is time.value;
  begin
    GET_MTIME(filePath, modificationTime.year, modificationTime.month, modificationTime.day,
        modificationTime.hour, modificationTime.minute, modificationTime.second,
        modificationTime.micro_second, modificationTime.timeZone,
        modificationTime.daylightSavingTime);
  end func;


(**
 *  Set the access time of a file.
 *  @exception MEMORY_ERROR Not enough memory to convert ''filePath''
 *             to the system path type.
 *  @exception RANGE_ERROR ''filePath'' does not use the standard path
 *             representation or it cannot be converted to the system
 *             path type.
 *  @exception RANGE_ERROR ''aTime'' is invalid or cannot be
 *             converted to the system file time.
 *  @exception FILE_ERROR A system function returns an error.
 *)
const proc: setATime (in string: filePath, in time: aTime) is func
  begin
    SET_ATIME(filePath, aTime.year, aTime.month, aTime.day,
        aTime.hour, aTime.minute, aTime.second,
        aTime.micro_second, aTime.timeZone);
  end func;


(**
 *  Set the modification time of a file.
 *  @exception MEMORY_ERROR Not enough memory to convert ''filePath''
 *             to the system path type.
 *  @exception RANGE_ERROR ''filePath'' does not use the standard path
 *             representation or it cannot be converted to the system
 *             path type.
 *  @exception RANGE_ERROR ''aTime'' is invalid or cannot be
 *             converted to the system file time.
 *  @exception FILE_ERROR A system function returns an error.
 *)
const proc: setMTime (in string: filePath, in time: aTime) is func
  begin
    SET_MTIME(filePath, aTime.year, aTime.month, aTime.day,
        aTime.hour, aTime.minute, aTime.second,
        aTime.micro_second, aTime.timeZone);
  end func;


(**
 *  Reads the destination of a symbolic link.
 *  @return The destination refered by the symbolic link.
 *  @exception MEMORY_ERROR Not enough memory to convert ''filePath''
 *             to the system path type or not enough memory to
 *             represent the result [[string]].
 *  @exception RANGE_ERROR ''filePath'' does not use the standard path
 *             representation or it cannot be converted to the system
 *             path type.
 *  @exception FILE_ERROR The file described with the path does not
 *             exist or is not a symbolic link.
 *)
const func string: readlink (in string: filePath)            is action "CMD_READLINK";


(**
 *  Create a symbolic link.
 *  The symbolic link ''destPath'' will refer to ''sourcePath'' afterwards.
 *  @param sourcePath String to be contained in the symbolic link.
 *  @param destPath Name of the symbolic link to be created.
 *  @exception MEMORY_ERROR Not enough memory to convert sourcePath or
 *             destPath to the system path type.
 *  @exception RANGE_ERROR ''sourcePath'' or ''destPath'' does not use the
 *             standard path representation or one of them cannot be
 *             converted to the system path type.
 *  @exception FILE_ERROR A system function returns an error.
 *)
const proc: symlink (in string: sourcePath, in string: destPath)   is action "CMD_SYMLINK";


(**
 *  Remove a file of any type unless it is a directory that is not empty.
 *  An attempt to remove a directory that is not empty triggers FILE_ERROR.
 *  @exception MEMORY_ERROR Not enough memory to convert ''filePath'' to
 *             the system path type.
 *  @exception RANGE_ERROR ''filePath'' does not use the standard path
 *             representation or it cannot be converted to the system
 *             path type.
 *  @exception FILE_ERROR The file does not exist or it is a directory
 *             that is not empty or a system function returns an error.
 *)
const proc: removeFile (in string: filePath)                 is action "CMD_REMOVE_FILE";


(**
 *  Remove a file of any type inclusive a directory tree.
 *  @exception MEMORY_ERROR Not enough memory to convert ''filePath'' to
 *             the system path type.
 *  @exception RANGE_ERROR ''filePath'' does not use the standard path
 *             representation or it cannot be converted to the system
 *             path type.
 *  @exception FILE_ERROR The file does not exist or a system function
 *             returns an error.
 *)
const proc: removeTree (in string: filePath)                 is action "CMD_REMOVE_TREE";


(**
 *  Copy a file or directory tree.
 *  Permissions/mode, ownership and timestamps of the destination file
 *  are determined independent of the corresponding source properties.
 *  The destination file gets the permissions/mode defined by umask.
 *  The user executing the program is the owner of the destination file.
 *  The timestamps of the destination file are set to the current time.
 *  Symbolic links in ''sourcePath'' are always followed.
 *  Therefore ''copyFile'' will never create a symbolic link.
 *  Note that ''copyFile'' does not preserve hard links (they are
 *  resolved to distinct files).
 *  @exception MEMORY_ERROR Not enough memory to convert ''sourcePath''
 *             or ''destPath'' to the system path type.
 *  @exception RANGE_ERROR ''sourcePath'' or ''destPath'' does not use
 *             the standard path representation or one of them cannot be
 *             converted to the system path type.
 *  @exception FILE_ERROR Source file does not exist, destination file
 *             already exists or a system function returns an error.
 *)
const proc: copyFile (in string: sourcePath, in string: destPath)  is action "CMD_COPY_FILE";


(**
 *  Clone a file or directory tree.
 *  Permissions/mode, ownership and timestamps of the original are
 *  preserved. Symlinks are not followed. Instead the symlink is
 *  copied. Note that ''cloneFile'' does not preserve hard links (they
 *  are resolved to distinct files).
 *  @exception MEMORY_ERROR Not enough memory to convert
 *             ''sourcePath'' or ''destPath'' to the system path type.
 *  @exception RANGE_ERROR ''sourcePath'' or ''destPath'' does not use
 *             the standard path representation or one of them cannot be
 *             converted to the system path type.
 *  @exception FILE_ERROR Source file does not exist, destination file
 *             already exists or a system function returns an error.
 *)
const proc: cloneFile (in string: sourcePath, in string: destPath) is action "CMD_CLONE_FILE";


(**
 *  Move and rename a file or directory tree.
 *  The function uses the C ''rename()'' function. When ''rename()'' fails
 *  the file (or directory tree) is cloned with ''cloneFile'' (which
 *  preserves permissions/mode, ownership and timestamps) to the new
 *  place and with the new name. When ''cloneFile'' succeeds the original
 *  file is deleted. When ''cloneFile'' fails (no space on device or
 *  other reason) all remains of the failed clone are removed. Note
 *  that ''cloneFile'' works for symbolic links but does not preserve
 *  hard links (they are resolved to distinct files).
 *  @exception MEMORY_ERROR Not enough memory to convert ''sourcePath''
 *             or ''destPath'' to the system path type.
 *  @exception RANGE_ERROR ''sourcePath'' or ''destPath'' does not use
 *             the standard path representation or one of them cannot be
 *             converted to the system path type.
 *  @exception FILE_ERROR Source file does not exist, destination file
 *             already exists or a system function returns an error.
 *)
const proc: moveFile (in string: sourcePath, in string: destPath)  is action "CMD_MOVE";


(**
 *  Creates a new directory.
 *  @exception MEMORY_ERROR Not enough memory to convert ''dirPath'' to
 *             the system path type.
 *  @exception RANGE_ERROR ''dirPath'' does not use the standard path
 *             representation or it cannot be converted to the system
 *             path type.
 *  @exception FILE_ERROR A system function returns an error.
 *)
const proc: mkdir (in string: dirPath)                       is action "CMD_MKDIR";


(**
 *  Determine the current working directory of the calling process.
 *  @return The absolute path of the current working directory.
 *  @exception MEMORY_ERROR Not enough memory to represent the
 *             result [[string]].
 *  @exception FILE_ERROR The system function returns an error.
 *)
const func string: getcwd                                    is action "CMD_GETCWD";


(**
 *  Changes the current working directory of the calling process.
 *  @exception MEMORY_ERROR Not enough memory to convert ''dirPath'' to
 *             the system path type.
 *  @exception RANGE_ERROR ''dirPath'' does not use the standard path
 *             representation or it cannot be converted to the system
 *             path type.
 *  @exception FILE_ERROR A system function returns an error.
 *)
const proc: chdir (in string: dirPath)                       is action "CMD_CHDIR";


(**
 *  Determine the home directory of the user.
 *  This function should be preferred over the use of an environment
 *  variable such as $HOME. $HOME is not supported under all operating
 *  systems and it is not guaranteed, that it uses the standard path
 *  representation.
 *  @return The absolute path of the home directory.
 *  @exception MEMORY_ERROR Not enough memory to represent the
 *             result [[string]].
 *  @exception FILE_ERROR Not able to determine the home directory.
 *)
const func string: homeDir                                   is action "CMD_HOME_DIR";


(**
 *  Determine the absolute path for a given ''path''.
 *   toAbsolute(getcwd, "aFile")    -->  Returns e.g. "/home/myuser/aFile"
 *   toAbsolute(".", "aFile")       -->  Returns e.g. "/home/myuser/aFile"
 *   toAbsolute("/usr", "include")  -->  Returns "/usr/include"
 *  @param basePath Path of the base location. The relative ''path'' is
 *         relative to this location.
 *  @param path Absolute or relative path for which the absolute path should
 *         be determined:
 *  @return ''path'' if ''path'' is already absolute, or
 *          concatenate ''basePath'' with ''path''.
 *)
const func string: toAbsPath (in string: basePath, in string: path) is func
  result
    var string: absolutePath is "";
  local
    var integer: dotdotPos is 0;
    var integer: slashPos is 0;
  begin
    if startsWith(path, "/") then
      absolutePath := path;
    elsif basePath = "/" then
      absolutePath := "/" & path;
    elsif startsWith(basePath, "/") then
      absolutePath := basePath & "/" & path;
    else
      absolutePath := getcwd & "/" & basePath & "/" & path;
    end if;
    dotdotPos := pos(absolutePath, "/..");
    while dotdotPos <> 0 do
      slashPos := rpos(absolutePath, '/', pred(dotdotPos));
      if length(absolutePath) = dotdotPos + 2 then
        if slashPos <= 1 then
          absolutePath := "/";
        else
          absolutePath := absolutePath[.. pred(slashPos)];
        end if;
        dotdotPos := 0;
      elsif absolutePath[dotdotPos + 3] = '/' then
        if slashPos <> 0 then
          absolutePath := absolutePath[.. pred(slashPos)] & absolutePath[dotdotPos + 3 ..];
        else
          absolutePath := absolutePath[dotdotPos + 3 ..];
        end if;
        dotdotPos := pos(absolutePath, "/..");
      else
        dotdotPos := pos(absolutePath, "/..", succ(dotdotPos));
      end if;
    end while;
    absolutePath := replace(absolutePath, "/./", "/");
    if endsWith(absolutePath, "/.") then
      if absolutePath = "/." then
        absolutePath := "/";
      else
        absolutePath := absolutePath[.. length(absolutePath) - 2];
      end if;
    end if;
    # writeln("toAbsPath(" <& literal(basePath) <& ", " <& literal(path) <&
    #         ") --> " <& literal(absolutePath));
  end func;


const func string: parentDir (in string: path) is func
  result
    var string: parentDir is "";
  local
    var integer: slashPos is 0;
  begin
    slashPos := rpos(path, '/');
    if slashPos = 0 then
      parentDir := ".";
    elsif slashPos = 1 then
      parentDir := "/";
    else
      parentDir := path[.. pred(slashPos)];
    end if;
  end func;


(**
 *  Create the parent directories of the given 'filePath'.
 *  @exception MEMORY_ERROR Not enough memory to convert ''filePath'' to
 *             the system path type.
 *  @exception RANGE_ERROR ''filePath'' does not use the standard path
 *             representation or it cannot be converted to the system
 *             path type.
 *  @exception FILE_ERROR A system function returns an error, or
 *             a component of 'filePath' is not a directory.
 *)
const proc: makeParentDirs (in string: filePath) is func
  local
    var integer: slashPos is 0;
    var string: dirPath is "";
  begin
    slashPos := pos(filePath, '/');
    if slashPos = 1 then
      slashPos := pos(filePath, '/', succ(slashPos));
    end if;
    while slashPos <> 0 do
      dirPath := filePath[.. pred(slashPos)];
      if fileTypeSL(dirPath) = FILE_ABSENT then
        mkdir(dirPath);
        slashPos := pos(filePath, '/', succ(slashPos));
      elsif fileTypeSL(dirPath) = FILE_DIR then
        slashPos := pos(filePath, '/', succ(slashPos));
      else
        raise FILE_ERROR;
      end if;
    end while;
  end func;


const func string: convDosPath (in string: path) is func
  result
    var string: stdPath is "";
  begin
    # Path delimiter is slash
    stdPath := replace(path, "\\", "/");
    # Convert drive letters to standard path
    if (length(stdPath) = 2 or (length(stdPath) >= 3 and stdPath[3] = '/')) and
        stdPath[2] = ':' and lower(stdPath[1]) >= 'a' and lower(stdPath[1]) <= 'z' then
      stdPath @:= [2] lower(stdPath[1]);
      stdPath @:= [1] '/';
    end if;
    # Remove double slashes
    stdPath := replaceN(stdPath, "//", "/");
    # Remove slash at end of path
    while stdPath <> "/" and endsWith(stdPath, "/") do
      stdPath := stdPath[.. pred(length(stdPath))];
    end while;
  end func;


const func string: toStdPath (in string: path) is func
  result
    var string: stdPath is "";
  begin
    stdPath := path;
    # Remove double slashes
    stdPath := replaceN(stdPath, "//", "/");
    # Remove slash at end of path
    while stdPath <> "/" and endsWith(stdPath, "/") do
      stdPath := stdPath[.. pred(length(stdPath))];
    end while;
  end func;


(**
 *  [[filesys#fileSys|FileSys]] implementation type to access operating system files.
 *)
const type: osFileSys is sub emptyFileSys struct
  end struct;


type_implements_interface(osFileSys, fileSys);


const func fileSys: openOsFileSys is func
  result
    var fileSys: newFileSys is fileSys.value;
  local
    var osFileSys: osFiles is osFileSys.value;
  begin
    newFileSys := toInterface(osFiles);
  end func;


(**
 *  [[filesys#fileSys|File system]] of the operating system files.
 *)
var fileSys: osFiles is openOsFileSys;


const proc: close (inout osFileSys: fileSystem) is noop;

const func array string: readDir (inout osFileSys: fileSystem, in string: dirPath) is
  return readDir(dirPath);

const func fileType: fileType (inout osFileSys: fileSystem, in string: filePath) is
  return fileType(filePath);

const func fileType: fileTypeSL (inout osFileSys: fileSystem, in string: filePath) is
  return fileTypeSL(filePath);

const func fileMode: fileMode (inout osFileSys: fileSystem, in string: filePath) is
  return fileMode(filePath);

const proc: setFileMode (inout osFileSys: fileSystem, in string: filePath,
    in fileMode: mode) is func
  begin
    setFileMode(filePath, mode);
  end func;

const func integer: fileSize (inout osFileSys: fileSystem, in string: filePath) is
  return fileSize(filePath);

const func bigInteger: bigFileSize (inout osFileSys: fileSystem, in string: filePath) is
  return bigFileSize(filePath);

const func time: getMTime (inout osFileSys: fileSystem, in string: filePath) is
  return getMTime(filePath);

const proc: setMTime (inout osFileSys: fileSystem, in string: filePath,
    in time: modificationTime) is func
  begin
    setMTime(filePath, modificationTime);
  end func;

const func file: open (inout osFileSys: fileSystem, in string: filePath, in string: mode) is
  return open(filePath, mode);

const func string: getFile (inout osFileSys: fileSystem, in string: filePath) is func
  result
    var string: data is "";
  local
    var file: workFile is STD_NULL;
  begin
    workFile := open(filePath, "r");
    if workFile <> STD_NULL then
      data := gets(workFile, length(workFile));
      close(workFile);
    else
      raise FILE_ERROR;
    end if;
  end func;

const proc: putFile (inout osFileSys: fileSystem, in string: filePath, in string: stri) is func
  local
    var file: workFile is STD_NULL;
  begin
    if stri <> "" then
      workFile := open(filePath, "w");
      if workFile <> STD_NULL then
        write(workFile, stri);
        close(workFile);
      end if;
    end if;
  end func;

const func string: readlink (inout osFileSys: fileSystem, in string: filePath) is
  return readlink(filePath);

const proc: mkdir (inout osFileSys: fileSystem, in string: dirPath) is func
  begin
    mkdir(dirPath);
  end func;

const func string: getcwd (inout osFileSys: fileSystem) is
  return getcwd;

const proc: chdir (inout osFileSys: fileSystem, in string: dirPath) is func
  begin
    chdir(dirPath);
  end func;
