path: root/README.md

# Qt Creator

Qt Creator is a cross-platform IDE for development with the Qt framework.

## Supported Platforms

The standalone binary packages support the following platforms:

* Windows 7 or later
* (K)Ubuntu Linux 16.04 (64-bit) or later
* macOS 10.13 or later

## Contributing

For instructions on how to set up the Qt Creator repository to contribute
patches back to Qt Creator, please check:

https://wiki.qt.io/Setting_up_Gerrit

See the following page for information about our coding standard:

https://doc-snapshots.qt.io/qtcreator-extending/coding-style.html

## Compiling Qt Creator

Prerequisites:

* Qt 5.11.0 or later
* Qt WebEngine module for QtWebEngine based help viewer
* On Windows:
    * ActiveState Active Perl
    * MinGW with g++ 5.3 or Visual Studio 2017 or later
    * jom
    * Python 3.5 or later (optional, needed for the python enabled debug helper)
* On Mac OS X: latest Xcode
* On Linux: g++ 5.3 or later
* LLVM/Clang 8.0.0 or later (optional, needed for the Clang Code Model, Clang Tools, ClangFormat,
  Clang PCH Manager and Clang Refactoring plugins, see the section
  "Get LLVM/Clang for the Clang Code Model". The LLVM C++ API provides no compatibility garantee,
  so if later versions don't compile we don't support that version.)
* CMake (for manual builds of LLVM/Clang, and Qt Creator itself)
* Ninja (optional, recommended for building with CMake)
* Qbs 1.7.x (optional, sources also contain Qbs itself)

The installed toolchains have to match the one Qt was compiled with.

You can build Qt Creator with

    # Optional, needed for the Clang Code Model if llvm-config is not in PATH:
    export LLVM_INSTALL_DIR=/path/to/llvm (or "set" on Windows)
    # Optional, disable Clang Refactoring
    export QTC_DISABLE_CLANG_REFACTORING=1
    # Optional, needed to let the QbsProjectManager plugin use system Qbs:
    export QBS_INSTALL_DIR=/path/to/qbs
    # Optional, needed for the Python enabled dumper on Windows
    set PYTHON_INSTALL_DIR=C:\path\to\python
    # Optional, needed to use system KSyntaxHighlighting:
    set KSYNTAXHIGHLIGHTING_LIB_DIR to folder holding the KSyntaxHighlighting library
    # if automatic deducing of include folder fails set KSYNTAXHIGHLIGHTING_INCLUDE_DIR as well
    # both variables can also be passed as qmake variables

    cd $SOURCE_DIRECTORY
    qmake -r
    make (or mingw32-make or nmake or jom, depending on your platform)

Installation ("make install") is not needed. It is however possible, using

    make install INSTALL_ROOT=$INSTALL_DIRECTORY

## Compiling Qt and Qt Creator on Windows

This section provides step by step instructions for compiling the latest
versions of Qt and Qt Creator on Windows. Alternatively, to avoid having to
compile Qt yourself, you can use one of the versions of Qt shipped with the Qt
SDK (release builds of Qt using MinGW and Visual C++ 2017 or later).
For detailed information on the supported compilers, see
<https://wiki.qt.io/Building_Qt_5_from_Git> .

   1.  Decide which compiler to use: MinGW or Microsoft Visual Studio. If you
       plan to contribute to Qt Creator, you should compile your changes with
       both compilers.

   2.  Install Git for Windows from <https://git-for-windows.github.io/>. If you plan to
       use the MinGW compiler suite, do not choose to put git in the
       default path of Windows command prompts. For more information, see
       step 9.

   3.  Create a working directory under which to check out Qt and Qt Creator,
       for example, `c:\work`. If you plan to use MinGW and Microsoft Visual
       Studio simultaneously or mix different Qt versions, we recommend
       creating a directory structure which reflects that. For example:
       `C:\work\qt5.11.0-vs15, C:\work\qt5.11.0-mingw`.

   4.  Download and install Perl from <https://www.activestate.com/activeperl>
       and check that perl.exe is added to the path. Run `perl -v` to verify
       that the version displayed is 5.10 or later. Note that git ships
       an outdated version 5.8 which cannot be used for Qt.

   5.  In the working directory, check out the respective branch of Qt from
       <https://code.qt.io/cgit/qt/qt5.git> (we recommend the highest released version).

   6.  Check out Qt Creator (master branch or latest version, see
       <https://code.qt.io/cgit/qt-creator/qt-creator.git>).
       You should now have the directories qt and creator under your working
       directory.

   7.  Install a compiler:
       - For a MinGW toolchain for Qt, see <https://wiki.qt.io/MinGW> .

       - For Microsoft Visual C++, install the Windows SDK and the "Debugging
         Tools for Windows" from the SDK image. We strongly recommend using the
         64-bit version and 64-bit compilers on 64-bit systems.

         For the Visual C++ compilers, it is recommended to use the tool 'jom'.
         It is a replacement for nmake that utilizes all CPU cores and thus
         speeds up compilation significantly. Download it from
         <https://download.qt.io/official_releases/jom>
         and add the executable to the path.

   8.  For convenience, we recommend creating shell prompts with the correct
       environment. This can be done by creating a .bat-file
       (such as, `<working_directory>\qtvars.bat`) that contains the environment
       variable settings.
       A `.bat`-file for MinGW looks like:

         set PATH=<path_to_qt>\[qtbase\]bin;<path_to_mingw>\bin;<working_directory>\creator\bin;%PATH%
         set QMAKESPEC=win32-g++

       For the Visual C++ compilers, call the `.bat` file that sets up the
       environment for the compiler (provided by the Windows SDK or the
       compiler):

         CALL "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" amd64
         set PATH=<path_to_qt>\[qtbase\]bin;<working_directory>\creator\bin;%PATH%
         set QMAKESPEC=win32-msvc2013

       You can create desktop links to the `.bat` files using the working
       directory and specifying

        %SystemRoot%\system32\cmd.exe /E:ON /V:ON  /k <working_directory>\qtvars.bat

   9.  When using MinGW, open the shell prompt and enter:

        sh.exe

       That should result in a `sh is not recognized as internal or external
       command...` error. If a `sh.exe` is found, the compile process will fail.
       You have to remove it from the path.

   10. To make use of the Clang Code Model:

       * Install LLVM/Clang - see the section "Get LLVM/Clang for the Clang
         Code Model".
       * Set the environment variable LLVM_INSTALL_DIR to the LLVM/Clang
         installation directory if llvm-config is not in PATH.
       * Before you launch Qt Creator you may prepend the PATH with
         the location of libclang.dll/.so that you want to be used.
         See more info in the section "Prebuilt LLVM/Clang packages".

   11. You are now ready to configure and build Qt and Qt Creator.
       Please see <https://wiki.qt.io/Building_Qt_5_from_Git> for
       recommended configure-options for Qt 5.
       To use MinGW, open the the shell prompt and enter:

         cd <path_to_qt>
         configure <configure_options> && mingw32-make -s
         cd ..\creator
         qmake && mingw32-make -s

       To use the Visual C++ compilers, enter:

         cd <path_to_qt>
         configure <configure_options> && jom
         cd ..\creator
         qmake && jom

   12. To launch Qt Creator, enter:
       qtcreator

   13. To test the Clang-based code model, verify that backend process
         bin\clangbackend.exe
       launches (displaying its usage).

       The library libclang.dll needs to be copied to the bin directory if
       Clang cannot be found in the path.

   14. When using  Visual C++ with the "Debugging Tools for Windows" installed,
       the extension library `qtcreatorcdbext.dll` to be loaded into the
       Windows console debugger (`cdb.exe`) should have been built under
       `lib\qtcreatorcdbext32` or `lib\qtcreatorcdbext64`.
       When using a 32 bit-build of Qt Creator with the 64 bit version of the
       "Debugging Tools for Windows" the library should also be built with
       a 64 bit compiler (rebuild `src\libs\qtcreatorcdbext` using a 64 bit
       compiler).

       If you are building 32 bit and running on a 64 bit
       Windows, you can obtain the 64 bit versions of the extension library
       and the binary `win64interrupt.exe`, which is required for
       debugging from the repository
       <https://code.qt.io/cgit/qt-creator/binary-artifacts.git/tree> .

   15. Qt Creator can be registered as a post-mortem debugger. This
       can be done in the options page or by running the tool qtcdebugger
       with administrative privileges passing the command line options
       -register/unregister, respectively. Alternatively,
       the required registry entries

        HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AeDebug
        HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows NT\CurrentVersion\AeDebug

       can be modified using the registry editor regedt32 to contain

        <path>\qt-creator\bin\qtcdebugger %ld %ld

       When using a self-built version of Qt Creator as post-mortem debugger, it needs to be
       able to find all dependent Qt-libraries and plugins when being launched by the
       system. The easiest way to provide them for Qt 5 is to run the tool windeployqt:

        windeployqt -quick -qmldir share\qtcreator\welcomescreen -qmldir src\plugins\qmlprofiler bin\qtcreator.exe lib\qtcreator lib\qtcreator\plugins

Note that unlike on Unix, you cannot overwrite executables that are running.
Thus, if you want to work on Qt Creator using Qt Creator, you need a
separate build of it. We recommend using a separate, release-built version
of Qt and Qt Creator to work on a debug-built version of Qt and Qt Creator
or using shadow builds.

## Get LLVM/Clang for the Clang Code Model

The Clang Code Model depends on the LLVM/Clang libraries. The currently
supported LLVM/Clang version is 8.0.

### Prebuilt LLVM/Clang packages

Prebuilt packages of LLVM/Clang can be downloaded from

    https://download.qt.io/development_releases/prebuilt/libclang/

This should be your preferred option because you will use the version that is
shipped together with Qt Creator (with backported/additional patches). In
addition, MinGW packages for Windows are faster due to profile-guided
optimization. If the prebuilt packages do not match your configuration, you
need to build LLVM/Clang manually.

If you use the MSVC compiler to build Qt Creator the suggested way is:
    1. Download both MSVC and MinGW packages of libclang.
    2. Use the MSVC version of libclang during the Qt Creator build.
    3. Prepend PATH variable used for the run time with the location of MinGW version of libclang.dll.
    4. Launch Qt Creator.

### Building LLVM/Clang manually

You need to install CMake in order to build LLVM/Clang.

Build LLVM/Clang by roughly following the instructions at
http://llvm.org/docs/GettingStarted.html#git-mirror:

   1. Clone LLVM/Clang and checkout a suitable branch

          git clone -b release_80-based --recursive https://code.qt.io/clang/llvm-project.git

   2. Build and install LLVM/Clang

          mkdir build
          cd build

      For Linux/macOS:

          cmake \
            -D CMAKE_BUILD_TYPE=Release \
            -D LLVM_ENABLE_RTTI=ON \
            -D LLVM_ENABLE_PROJECTS="clang;clang-tools-extra" \
            -D CMAKE_INSTALL_PREFIX=<installation location> \
            ../llvm-project/llvm
          cmake --build . --target install

      For Windows:

          cmake ^
            -G "NMake Makefiles JOM" ^
            -D CMAKE_BUILD_TYPE=Release ^
            -D LLVM_ENABLE_RTTI=ON ^
            -D LLVM_ENABLE_PROJECTS="clang;clang-tools-extra" ^
            -D CMAKE_INSTALL_PREFIX=<installation location> ^
            ..\llvm-project\llvm
          cmake --build . --target install

### Clang-Format

The ClangFormat plugin depends on the additional patch

    https://code.qt.io/cgit/clang/clang.git/commit/?h=release_80-based&id=fa1b9053729ec6a4425a44ec5502dd388928274a

While the plugin builds without it, it will be disabled on start with an error message.

Note that the plugin is disabled by default.

### Building Qt Creator with CMake

Qt Creator can also be built with CMake. The main Qt Creator dependencies, Qt and LLVM/Clang, both
offer CMake find packages, which reduce the steps of configuring Qt Creator to a minimum.

   Configure and build Qt Creator:

      mkdir build
      cd build

    For Linux/macOS:

      cmake \
        -G Ninja \
        -D CMAKE_BUILD_TYPE=Release \
        -D CMAKE_PREFIX_PATH=~/Qt/5.12.5/gcc_64;~/llvm \
        ../qt-creator
      cmake --build .

    For Windows:

      cmake ^
        -G Ninja ^
        -D CMAKE_BUILD_TYPE=Release ^
        -D CMAKE_PREFIX_PATH=c:\Qt\5.12.5\msvc2017_64;c:\llvm ^
        ..\qt-creator
      cmake --build .

## Third-party Components

Qt Creator includes the following third-party components,
we thank the authors who made this possible:

### YAML Parser yaml-cpp (MIT License)

  https://github.com/jbeder/yaml-cpp

  QtCreator/src/libs/3rdparty/yaml-cpp

  Copyright (c) 2008-2015 Jesse Beder.

  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in
  all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  THE SOFTWARE.

### KSyntaxHighlighting

  Syntax highlighting engine for Kate syntax definitions

  This is a stand-alone implementation of the Kate syntax highlighting
  engine. It's meant as a building block for text editors as well as
  for simple highlighted text rendering (e.g. as HTML), supporting both
  integration with a custom editor as well as a ready-to-use
  QSyntaxHighlighter sub-class.

  Distributed under the:

  MIT License

  Permission is hereby granted, free of charge, to any person obtaining
  a copy of this software and associated documentation files (the
  "Software"), to deal in the Software without restriction, including
  without limitation the rights to use, copy, modify, merge, publish,
  distribute, sublicense, and/or sell copies of the Software, and to
  permit persons to whom the Software is furnished to do so, subject to
  the following conditions:

  The above copyright notice and this permission notice shall be included
  in all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
  CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

  The source code of KSyntaxHighlighting can be found here:
      https://cgit.kde.org/syntax-highlighting.git
      QtCreator/src/libs/3rdparty/syntax-highlighting
      https://code.qt.io/cgit/qt-creator/qt-creator.git/tree/src/libs/3rdparty/syntax-highlighting

### Clazy

  https://github.com/KDE/clazy

  Copyright (C) 2015-2018 Clazy Team

  Distributed under GNU LIBRARY GENERAL PUBLIC LICENSE Version 2 (LGPL2).

  Integrated with patches from
  http://code.qt.io/cgit/clang/clang-tools-extra.git/.

### LLVM/Clang

  https://github.com/llvm/llvm-project.git

  Copyright (C) 2003-2019 LLVM Team

  Distributed under the University of Illinois/NCSA Open Source License (NCSA),
  see https://github.com/llvm/llvm-project/blob/master/llvm/LICENSE.TXT

  With backported/additional patches from https://code.qt.io/clang/llvm-project.git

### Reference implementation for std::experimental::optional

  https://github.com/akrzemi1/Optional

  QtCreator/src/libs/3rdparty/optional

  Copyright (C) 2011-2012 Andrzej Krzemienski

  Distributed under the Boost Software License, Version 1.0
  (see accompanying file LICENSE_1_0.txt or a copy at
  http://www.boost.org/LICENSE_1_0.txt)

  The idea and interface is based on Boost.Optional library
  authored by Fernando Luis Cacciola Carballal

### Implementation for std::variant

  https://github.com/mpark/variant

  QtCreator/src/libs/3rdparty/variant

  Copyright Michael Park, 2015-2017

  Distributed under the Boost Software License, Version 1.0.
  (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)

### Open Source front-end for C++ (license MIT), enhanced for use in Qt Creator

  Roberto Raggi <roberto.raggi@gmail.com>

  QtCreator/src/shared/cplusplus

  Copyright 2005 Roberto Raggi <roberto@kdevelop.org>

  Permission to use, copy, modify, distribute, and sell this software and its
  documentation for any purpose is hereby granted without fee, provided that
  the above copyright notice appear in all copies and that both that
  copyright notice and this permission notice appear in supporting
  documentation.

  The above copyright notice and this permission notice shall be included in
  all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
  KDEVELOP TEAM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

### Open Source tool for generating C++ code that classifies keywords (license MIT)

  Roberto Raggi <roberto.raggi@gmail.com>

  QtCreator/src/tools/3rdparty/cplusplus-keywordgen

  Copyright (c) 2007 Roberto Raggi <roberto.raggi@gmail.com>

  Permission is hereby granted, free of charge, to any person obtaining a copy of
  this software and associated documentation files (the "Software"), to deal in
  the Software without restriction, including without limitation the rights to
  use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
  the Software, and to permit persons to whom the Software is furnished to do so,
  subject to the following conditions:

  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
  FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
  IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

### SQLite, in-process library that implements a SQL database engine

SQLite (https://www.sqlite.org) is in the Public Domain.

### ClassView and ImageViewer plugins

  Copyright (C) 2016 The Qt Company Ltd.

  All rights reserved.
  Copyright (C) 2016 Denis Mingulov.

  Contact: http://www.qt.io

  This file is part of Qt Creator.

  You may use this file under the terms of the BSD license as follows:

  "Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are
  met:
    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in
      the documentation and/or other materials provided with the
      distribution.
    * Neither the name of The Qt Company Ltd and its Subsidiary(-ies) nor
      the names of its contributors may be used to endorse or promote
      products derived from this software without specific prior written
      permission.

  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."

### Source Code Pro font

  Copyright 2010, 2012 Adobe Systems Incorporated (http://www.adobe.com/),
  with Reserved Font Name 'Source'. All Rights Reserved. Source is a
  trademark of Adobe Systems Incorporated in the United States
  and/or other countries.

  This Font Software is licensed under the SIL Open Font License, Version 1.1.

  The font and license files can be found in QtCreator/src/libs/3rdparty/fonts.

### JSON Library by Niels Lohmann

  Used by the Chrome Trace Format Visualizer plugin instead of QJson
  because of QJson's current hard limit of 128 Mb object size and
  trace files often being much larger.

  The sources can be found in `QtCreator/src/libs/3rdparty/json`.

  The class is licensed under the MIT License:

  Copyright © 2013-2019 Niels Lohmann

  Permission is hereby granted, free of charge, to any person obtaining a
  copy of this software and associated documentation files (the “Software”), to
  deal in the Software without restriction, including without limitation the
  rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is furnished
  to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included
  in all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS
  OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  SOFTWARE.
  \endcode

  The class contains the UTF-8 Decoder from Bjoern Hoehrmann which is
  licensed under the MIT License (see above). Copyright © 2008-2009 Björn
  Hoehrmann bjoern@hoehrmann.de

  The class contains a slightly modified version of the Grisu2 algorithm
  from Florian Loitsch which is licensed under the MIT License (see above).
  Copyright © 2009 Florian Loitsch