1  GNU GENERAL PUBLIC LICENSE
  2  
  3  Version 2, June 1991
  4  
  5  Copyright (C) 1989, 1991 Free Software Foundation, Inc.
  6  
  7  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
  8  
  9  Everyone is permitted to copy and distribute verbatim copies of this license
 10  document, but changing it is not allowed.
 11  
 12  Preamble
 13  
 14  The licenses for most software are designed to take away your freedom to share
 15  and change it. By contrast, the GNU General Public License is intended to
 16  guarantee your freedom to share and change free software--to make sure the
 17  software is free for all its users. This General Public License applies to
 18  most of the Free Software Foundation's software and to any other program whose
 19  authors commit to using it. (Some other Free Software Foundation software
 20  is covered by the GNU Lesser General Public License instead.) You can apply
 21  it to your programs, too.
 22  
 23  When we speak of free software, we are referring to freedom, not price. Our
 24  General Public Licenses are designed to make sure that you have the freedom
 25  to distribute copies of free software (and charge for this service if you
 26  wish), that you receive source code or can get it if you want it, that you
 27  can change the software or use pieces of it in new free programs; and that
 28  you know you can do these things.
 29  
 30  To protect your rights, we need to make restrictions that forbid anyone to
 31  deny you these rights or to ask you to surrender the rights. These restrictions
 32  translate to certain responsibilities for you if you distribute copies of
 33  the software, or if you modify it.
 34  
 35  For example, if you distribute copies of such a program, whether gratis or
 36  for a fee, you must give the recipients all the rights that you have. You
 37  must make sure that they, too, receive or can get the source code. And you
 38  must show them these terms so they know their rights.
 39  
 40  We protect your rights with two steps: (1) copyright the software, and (2)
 41  offer you this license which gives you legal permission to copy, distribute
 42  and/or modify the software.
 43  
 44  Also, for each author's protection and ours, we want to make certain that
 45  everyone understands that there is no warranty for this free software. If
 46  the software is modified by someone else and passed on, we want its recipients
 47  to know that what they have is not the original, so that any problems introduced
 48  by others will not reflect on the original authors' reputations.
 49  
 50  Finally, any free program is threatened constantly by software patents. We
 51  wish to avoid the danger that redistributors of a free program will individually
 52  obtain patent licenses, in effect making the program proprietary. To prevent
 53  this, we have made it clear that any patent must be licensed for everyone's
 54  free use or not licensed at all.
 55  
 56  The precise terms and conditions for copying, distribution and modification
 57  follow.
 58  
 59  TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
 60  
 61  0. This License applies to any program or other work which contains a notice
 62  placed by the copyright holder saying it may be distributed under the terms
 63  of this General Public License. The "Program", below, refers to any such program
 64  or work, and a "work based on the Program" means either the Program or any
 65  derivative work under copyright law: that is to say, a work containing the
 66  Program or a portion of it, either verbatim or with modifications and/or translated
 67  into another language. (Hereinafter, translation is included without limitation
 68  in the term "modification".) Each licensee is addressed as "you".
 69  
 70  Activities other than copying, distribution and modification are not covered
 71  by this License; they are outside its scope. The act of running the Program
 72  is not restricted, and the output from the Program is covered only if its
 73  contents constitute a work based on the Program (independent of having been
 74  made by running the Program). Whether that is true depends on what the Program
 75  does.
 76  
 77  1. You may copy and distribute verbatim copies of the Program's source code
 78  as you receive it, in any medium, provided that you conspicuously and appropriately
 79  publish on each copy an appropriate copyright notice and disclaimer of warranty;
 80  keep intact all the notices that refer to this License and to the absence
 81  of any warranty; and give any other recipients of the Program a copy of this
 82  License along with the Program.
 83  
 84  You may charge a fee for the physical act of transferring a copy, and you
 85  may at your option offer warranty protection in exchange for a fee.
 86  
 87  2. You may modify your copy or copies of the Program or any portion of it,
 88  thus forming a work based on the Program, and copy and distribute such modifications
 89  or work under the terms of Section 1 above, provided that you also meet all
 90  of these conditions:
 91  
 92  a) You must cause the modified files to carry prominent notices stating that
 93  you changed the files and the date of any change.
 94  
 95  b) You must cause any work that you distribute or publish, that in whole or
 96  in part contains or is derived from the Program or any part thereof, to be
 97  licensed as a whole at no charge to all third parties under the terms of this
 98  License.
 99  
100  c) If the modified program normally reads commands interactively when run,
101  you must cause it, when started running for such interactive use in the most
102  ordinary way, to print or display an announcement including an appropriate
103  copyright notice and a notice that there is no warranty (or else, saying that
104  you provide a warranty) and that users may redistribute the program under
105  these conditions, and telling the user how to view a copy of this License.
106  (Exception: if the Program itself is interactive but does not normally print
107  such an announcement, your work based on the Program is not required to print
108  an announcement.)
109  
110  These requirements apply to the modified work as a whole. If identifiable
111  sections of that work are not derived from the Program, and can be reasonably
112  considered independent and separate works in themselves, then this License,
113  and its terms, do not apply to those sections when you distribute them as
114  separate works. But when you distribute the same sections as part of a whole
115  which is a work based on the Program, the distribution of the whole must be
116  on the terms of this License, whose permissions for other licensees extend
117  to the entire whole, and thus to each and every part regardless of who wrote
118  it.
119  
120  Thus, it is not the intent of this section to claim rights or contest your
121  rights to work written entirely by you; rather, the intent is to exercise
122  the right to control the distribution of derivative or collective works based
123  on the Program.
124  
125  In addition, mere aggregation of another work not based on the Program with
126  the Program (or with a work based on the Program) on a volume of a storage
127  or distribution medium does not bring the other work under the scope of this
128  License.
129  
130  3. You may copy and distribute the Program (or a work based on it, under Section
131  2) in object code or executable form under the terms of Sections 1 and 2 above
132  provided that you also do one of the following:
133  
134  a) Accompany it with the complete corresponding machine-readable source code,
135  which must be distributed under the terms of Sections 1 and 2 above on a medium
136  customarily used for software interchange; or,
137  
138  b) Accompany it with a written offer, valid for at least three years, to give
139  any third party, for a charge no more than your cost of physically performing
140  source distribution, a complete machine-readable copy of the corresponding
141  source code, to be distributed under the terms of Sections 1 and 2 above on
142  a medium customarily used for software interchange; or,
143  
144  c) Accompany it with the information you received as to the offer to distribute
145  corresponding source code. (This alternative is allowed only for noncommercial
146  distribution and only if you received the program in object code or executable
147  form with such an offer, in accord with Subsection b above.)
148  
149  The source code for a work means the preferred form of the work for making
150  modifications to it. For an executable work, complete source code means all
151  the source code for all modules it contains, plus any associated interface
152  definition files, plus the scripts used to control compilation and installation
153  of the executable. However, as a special exception, the source code distributed
154  need not include anything that is normally distributed (in either source or
155  binary form) with the major components (compiler, kernel, and so on) of the
156  operating system on which the executable runs, unless that component itself
157  accompanies the executable.
158  
159  If distribution of executable or object code is made by offering access to
160  copy from a designated place, then offering equivalent access to copy the
161  source code from the same place counts as distribution of the source code,
162  even though third parties are not compelled to copy the source along with
163  the object code.
164  
165  4. You may not copy, modify, sublicense, or distribute the Program except
166  as expressly provided under this License. Any attempt otherwise to copy, modify,
167  sublicense or distribute the Program is void, and will automatically terminate
168  your rights under this License. However, parties who have received copies,
169  or rights, from you under this License will not have their licenses terminated
170  so long as such parties remain in full compliance.
171  
172  5. You are not required to accept this License, since you have not signed
173  it. However, nothing else grants you permission to modify or distribute the
174  Program or its derivative works. These actions are prohibited by law if you
175  do not accept this License. Therefore, by modifying or distributing the Program
176  (or any work based on the Program), you indicate your acceptance of this License
177  to do so, and all its terms and conditions for copying, distributing or modifying
178  the Program or works based on it.
179  
180  6. Each time you redistribute the Program (or any work based on the Program),
181  the recipient automatically receives a license from the original licensor
182  to copy, distribute or modify the Program subject to these terms and conditions.
183  You may not impose any further restrictions on the recipients' exercise of
184  the rights granted herein. You are not responsible for enforcing compliance
185  by third parties to this License.
186  
187  7. If, as a consequence of a court judgment or allegation of patent infringement
188  or for any other reason (not limited to patent issues), conditions are imposed
189  on you (whether by court order, agreement or otherwise) that contradict the
190  conditions of this License, they do not excuse you from the conditions of
191  this License. If you cannot distribute so as to satisfy simultaneously your
192  obligations under this License and any other pertinent obligations, then as
193  a consequence you may not distribute the Program at all. For example, if a
194  patent license would not permit royalty-free redistribution of the Program
195  by all those who receive copies directly or indirectly through you, then the
196  only way you could satisfy both it and this License would be to refrain entirely
197  from distribution of the Program.
198  
199  If any portion of this section is held invalid or unenforceable under any
200  particular circumstance, the balance of the section is intended to apply and
201  the section as a whole is intended to apply in other circumstances.
202  
203  It is not the purpose of this section to induce you to infringe any patents
204  or other property right claims or to contest validity of any such claims;
205  this section has the sole purpose of protecting the integrity of the free
206  software distribution system, which is implemented by public license practices.
207  Many people have made generous contributions to the wide range of software
208  distributed through that system in reliance on consistent application of that
209  system; it is up to the author/donor to decide if he or she is willing to
210  distribute software through any other system and a licensee cannot impose
211  that choice.
212  
213  This section is intended to make thoroughly clear what is believed to be a
214  consequence of the rest of this License.
215  
216  8. If the distribution and/or use of the Program is restricted in certain
217  countries either by patents or by copyrighted interfaces, the original copyright
218  holder who places the Program under this License may add an explicit geographical
219  distribution limitation excluding those countries, so that distribution is
220  permitted only in or among countries not thus excluded. In such case, this
221  License incorporates the limitation as if written in the body of this License.
222  
223  9. The Free Software Foundation may publish revised and/or new versions of
224  the General Public License from time to time. Such new versions will be similar
225  in spirit to the present version, but may differ in detail to address new
226  problems or concerns.
227  
228  Each version is given a distinguishing version number. If the Program specifies
229  a version number of this License which applies to it and "any later version",
230  you have the option of following the terms and conditions either of that version
231  or of any later version published by the Free Software Foundation. If the
232  Program does not specify a version number of this License, you may choose
233  any version ever published by the Free Software Foundation.
234  
235  10. If you wish to incorporate parts of the Program into other free programs
236  whose distribution conditions are different, write to the author to ask for
237  permission. For software which is copyrighted by the Free Software Foundation,
238  write to the Free Software Foundation; we sometimes make exceptions for this.
239  Our decision will be guided by the two goals of preserving the free status
240  of all derivatives of our free software and of promoting the sharing and reuse
241  of software generally.
242  
243     NO WARRANTY
244  
245  11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR
246  THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE
247  STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM
248  "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING,
249  BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
250  FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE
251  OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME
252  THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
253  
254  12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
255  WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE
256  THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
257  GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE
258  OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA
259  OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES
260  OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH
261  HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
262  END OF TERMS AND CONDITIONS
263  
264  How to Apply These Terms to Your New Programs
265  
266  If you develop a new program, and you want it to be of the greatest possible
267  use to the public, the best way to achieve this is to make it free software
268  which everyone can redistribute and change under these terms.
269  
270  To do so, attach the following notices to the program. It is safest to attach
271  them to the start of each source file to most effectively convey the exclusion
272  of warranty; and each file should have at least the "copyright" line and a
273  pointer to where the full notice is found.
274  
275  <one line to give the program's name and an idea of what it does.>
276  
277  Copyright (C) <yyyy> <name of author>
278  
279  This program is free software; you can redistribute it and/or modify it under
280  the terms of the GNU General Public License as published by the Free Software
281  Foundation; either version 2 of the License, or (at your option) any later
282  version.
283  
284  This program is distributed in the hope that it will be useful, but WITHOUT
285  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
286  FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
287  
288  You should have received a copy of the GNU General Public License along with
289  this program; if not, write to the Free Software Foundation, Inc., 51 Franklin
290  Street, Fifth Floor, Boston, MA 02110-1301, USA.
291  
292  Also add information on how to contact you by electronic and paper mail.
293  
294  If the program is interactive, make it output a short notice like this when
295  it starts in an interactive mode:
296  
297  Gnomovision version 69, Copyright (C) year name of author Gnomovision comes
298  with ABSOLUTELY NO WARRANTY; for details type `show w'. This is free software,
299  and you are welcome to redistribute it under certain conditions; type `show
300  c' for details.
301  
302  The hypothetical commands `show w' and `show c' should show the appropriate
303  parts of the General Public License. Of course, the commands you use may be
304  called something other than `show w' and `show c'; they could even be mouse-clicks
305  or menu items--whatever suits your program.
306  
307  You should also get your employer (if you work as a programmer) or your school,
308  if any, to sign a "copyright disclaimer" for the program, if necessary. Here
309  is a sample; alter the names:
310  
311  Yoyodyne, Inc., hereby disclaims all copyright interest in the program `Gnomovision'
312  (which makes passes at compilers) written by James Hacker.
313  
314  <signature of Ty Coon>, 1 April 1989 Ty Coon, President of Vice This General
315  Public License does not permit incorporating your program into proprietary
316  programs. If your program is a subroutine library, you may consider it more
317  useful to permit linking proprietary applications with the library. If this
318  is what you want to do, use the GNU Lesser General Public License instead
319  of this License.