.. _gpl:

================
 GPL
================

GNU GENERAL PUBLIC LICENSE
===========================

Version 2, June 1991
::

  Copyright (C) 1989, 1991 Free Software Foundation, Inc.  
  59 Temple Place - Suite 330, Boston, MA  02111-1307, USA

  Everyone is permitted to copy and distribute verbatim copies
  of this license document, but changing it is not allowed.
  

Preamble
---------

The licenses for most software are designed to take away your
freedom to share and change it. By contrast, the GNU General
Public License is intended to guarantee your freedom to share
and change free software--to make sure the software is free 
for all its users. This General Public License applies to 
most of the Free Software Foundation's software and to any
other program whose authors commit to using it. (Some other
Free Software Foundation software is covered by the GNU 
Library General Public License instead.) You can apply it to
your programs, too.

When we speak of free software, we are referring to freedom,
not price. Our General Public Licenses are designed to make
sure that you have the freedom to distribute copies of free
software (and charge for this service if you wish), that you
receive source code or can get it if you want it, that you 
can change the software or use pieces of it in new free 
programs; and that you know you can do these things.

To protect your rights, we need to make restrictions that 
forbid anyone to deny you these rights or to ask you to 
surrender the rights. These restrictions translate to certain
responsibilities for you if you distribute copies of the 
software, or if you modify it.

For example, if you distribute copies of such a program, 
whether gratis or for a fee, you must give the recipients 
all the rights that you have. You must make sure that they, 
too, receive or can get the source code. And you must show 
them these terms so they know their rights.

We protect your rights with two steps: (1) copyright the 
software, and (2) offer you this license which gives you 
legal permission to copy, distribute and/or modify the 
software.

Also, for each author's protection and ours, we want to 
make certain that everyone understands that there is no 
warranty for this free software. If the software is modified
by someone else and passed on, we want its recipients to 
know that what they have is not the original, so that any 
problems introduced by others will not reflect on the 
original authors' reputations.

Finally, any free program is threatened constantly by software
patents. We wish to avoid the danger that redistributors of a
free program will individually obtain patent licenses, 
in effect making the program proprietary. To prevent this,
we have made it clear that any patent must be licensed for 
everyone's free use or not licensed at all.

The precise terms and conditions for copying, distribution 
and modification follow.


TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
----------------------------------------------------------------

0. This License applies to any program or other work which 
   contains a notice placed by the copyright holder saying it
   may be distributed under the terms of this General Public
   License. The "Program", below, refers to any such program
   or work, and a "work based on the Program" means either 
   the Program or any derivative work under copyright law:
   that is to say, a work containing the Program or a portion
   of it, either verbatim or with modifications and/or 
   translated into another language. (Hereinafter, translation
   is included without limitation in the term "modification".)
   Each licensee is addressed as "you".

   Activities other than copying, distribution and modification
   are not covered by this License; they are outside its scope.
   The act of running the Program is not restricted, and the 
   output from the Program is covered only if its contents 
   constitute a work based on the Program (independent of 
   having been made by running the Program). Whether that is
   true depends on what the Program does. 

1. You may copy and distribute verbatim copies of the Program's
   source code as you receive it, in any medium, provided that
   you conspicuously and appropriately publish on each copy an
   appropriate copyright notice and disclaimer of warranty; 
   keep intact all the notices that refer to this License and
   to the absence of any warranty; and give any other 
   recipients of the Program a copy of this License along with
   the Program.

   You may charge a fee for the physical act of transferring
   a copy, and you may at your option offer warranty 
   protection in exchange for a fee. 

2. You may modify your copy or copies of the Program or any 
   portion of it, thus forming a work based on the Program, 
   and copy and distribute such modifications or work under 
   the terms of Section 1 above, provided that you also meet 
   all of these conditions:
   
   a) You must cause the modified files to carry prominent 
      notices stating that you changed the files and the date 
      of any change.
      
   b) You must cause any work that you distribute or publish,
      that in whole or in part contains or is derived from 
      the Program or any part thereof, to be licensed as a 
      whole at no charge to all third parties under the terms
      of this License.
    
   c) If the modified program normally reads commands 
      interactively when run, you must cause it, when started 
      running for such interactive use in the most ordinary 
      way, to print or display an announcement including an 
      appropriate copyright notice and a notice that there is
      no warranty (or else, saying that you provide a warranty)
      and that users may redistribute the program under these
      conditions, and telling the user how to view a copy of 
      this License. (Exception: if the Program itself is 
      interactive but does not normally print such an 
      announcement, your work based on the Program is not 
      required to print an announcement.)
    
   These requirements apply to the modified work as a whole.
   If identifiable sections of that work are not derived from
   the Program, and can be reasonably considered independent
   and separate works in themselves, then this License, and 
   its terms, do not apply to those sections when you 
   distribute them as separate works.  But when you distribute
   the same sections as part of a whole which is a work based 
   on the Program, the distribution of the whole must be on 
   the terms of this License, whose permissions for other 
   licensees extend to the entire whole, and thus to each and
   every part regardless of who wrote it.
   
   Thus, it is not the intent of this section to claim rights 
   or contest your rights to work written entirely by you; 
   rather, the intent is to exercise the right to control the
   distribution of derivative or collective works based on 
   the Program.
   
   In addition, mere aggregation of another work not based on 
   the Program with the Program (or with a work based on the 
   Program) on a volume of a storage or distribution medium 
   does not bring the other work under the scope of this 
   License.

3. You may copy and distribute the Program (or a work based on
   it, under Section 2) in object code or executable form 
   under the terms of Sections 1 and 2 above provided that 
   you also do one of the following:
   
   a) Accompany it with the complete corresponding 
      machine-readable source code, which must be distributed 
      under the terms of Sections 1 and 2 above on a medium 
      customarily used for software interchange; or,
      
   b) Accompany it with a written offer, valid for at least 
      three years, to give any third party, for a charge no 
      more than your cost of physically performing source 
      distribution, a complete machine-readable copy of the 
      corresponding source code, to be distributed under the 
      terms of Sections 1 and 2 above on a medium customarily
      used for software interchange; or,

   c) Accompany it with the information you received as to the
      offer to distribute corresponding source code. 
      (This alternative is allowed only for noncommercial 
      distribution and only if you received the program in 
      object code or executable form with such an offer, in 
      accord with Subsection b above.)
    
   The source code for a work means the preferred form of the
   work for making modifications to it. For an executable work,
   complete source code means all the source code for all 
   modules it contains, plus any associated interface 
   definition files, plus the scripts used to control 
   compilation and installation of the executable. However, 
   as a special exception, the source code distributed need 
   not include anything that is normally distributed (in 
   either source or binary form) with the major components 
   (compiler, kernel, and so on) of the operating system on 
   which the executable runs, unless that component itself 
   accompanies the executable.
   
   If distribution of executable or object code is made by 
   offering access to copy from a designated place, then 
   offering equivalent access to copy the source code from 
   the same place counts as distribution of the source code, 
   even though third parties are not compelled to copy the 
   source along with the object code.

4. You may not copy, modify, sublicense, or distribute the
   Program except as expressly provided under this License.
   Any attempt otherwise to copy, modify, sublicense or 
   distribute the Program is void, and will automatically 
   terminate your rights under this License. However, 
   parties who have received copies, or rights, from you 
   under this License will not have their licenses 
   terminated so long as such parties remain in full 
   compliance.

5. You are not required to accept this License, since you 
   have not signed it. However, nothing else grants you 
   permission to modify or distribute the Program or its 
   derivative works. These actions are prohibited by law 
   if you do not accept this License. Therefore, by modifying
   or distributing the Program (or any work based on the 
   Program), you indicate your acceptance of this License 
   to do so, and all its terms and conditions for copying, 
   distributing or modifying the Program or works based on 
   it.

6. Each time you redistribute the Program (or any work based
   on the Program), the recipient automatically receives a 
   license from the original licensor to copy, distribute or
   modify the Program subject to these terms and conditions.
   You may not impose any further restrictions on the 
   recipients' exercise of the rights granted herein. 
   You are not responsible for enforcing compliance by third 
   parties to this License.

7. If, as a consequence of a court judgment or allegation of 
   patent infringement or for any other reason (not limited 
   to patent issues), conditions are imposed on you (whether
   by court order, agreement or otherwise) that contradict 
   the conditions of this License, they do not excuse you 
   from the conditions of this License. If you cannot 
   distribute so as to satisfy simultaneously your 
   obligations under this License and any other pertinent
   obligations, then as a consequence you may not distribute
   the Program at all. For example, if a patent license 
   would not permit royalty-free redistribution of the 
   Program by all those who receive copies directly or 
   indirectly through you, then the only way you could 
   satisfy both it and this License would be to refrain 
   entirely from distribution of the Program.
   
   If any portion of this section is held invalid or 
   unenforceable under any particular circumstance, the 
   balance of the section is intended to apply and the 
   section as a whole is intended to apply in other 
   circumstances.
   
   It is not the purpose of this section to induce you to
   infringe any patents or other property right claims or
   to contest validity of any such claims; this section 
   has the sole purpose of protecting the integrity of 
   the free software distribution system, which is 
   implemented by public license practices. Many people have 
   made generous contributions to the wide range of software
   distributed through that system in reliance on consistent
   application of that system; it is up to the author/donor
   to decide if he or she is willing to distribute software
   through any other system and a licensee cannot impose 
   that choice.
   
   This section is intended to make thoroughly clear what
   is believed to be a consequence of the rest of this 
   License.
   
8. If the distribution and/or use of the Program is 
   restricted in certain countries either by patents or by 
   copyrighted interfaces, the original copyright holder who
   places the Program under this License may add an explicit
   geographical distribution limitation excluding those 
   countries, so that distribution is permitted only in or 
   among countries not thus excluded. In such case, this 
   License incorporates the limitation as if written in 
   the body of this License.
   
9. The Free Software Foundation may publish revised and/or 
   new versions of the General Public License from time to 
   time. Such new versions will be similar in spirit to the 
   present version, but may differ in detail to address new 
   problems or concerns.

   Each version is given a distinguishing version number.
   If the Program specifies a version number of this License
   which applies to it and "any later version", you have the
   option of following the terms and conditions either of 
   that version or of any later version published by the 
   Free Software Foundation. If the Program does not specify
   a version number of this License, you may choose any 
   version ever published by the Free Software Foundation.
   
10. If you wish to incorporate parts of the Program into 
    other free programs whose distribution conditions are 
    different, write to the author to ask for permission. 
    For software which is copyrighted by the Free Software 
    Foundation, write to the Free Software Foundation; we 
    sometimes make exceptions for this. Our decision will 
    be guided by the two goals of preserving the free 
    status of all derivatives of our free software and 
    of promoting the sharing and reuse of software generally.

**NO WARRANTY**

11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, 
    THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT 
    PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE 
    STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER 
    PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY 
    OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, 
    BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
    MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 
    THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF 
    THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE 
    DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY 
    SERVICING, REPAIR OR CORRECTION.


12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED
    TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER 
    PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE PROGRAM AS
    PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING 
    ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES
    ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM 
    (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING
    RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD 
    PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY 
    OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS 
    BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

**END OF TERMS AND CONDITIONS**
