license.txt

   1                     GNU GENERAL PUBLIC LICENSE
   2                        Version 2, June 1991
   3
   4  Copyright (C) 1989, 1991 Free Software Foundation, Inc.
   5                        51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
   6  Everyone is permitted to copy and distribute verbatim copies
   7  of this license document, but changing it is not allowed.
   8
   9                             Preamble
  10
  11   The licenses for most software are designed to take away your
  12 freedom to share and change it.  By contrast, the GNU General Public
  13 License is intended to guarantee your freedom to share and change free
  14 software--to make sure the software is free for all its users.  This
  15 General Public License applies to most of the Free Software
  16 Foundation's software and to any other program whose authors commit to
  17 using it.  (Some other Free Software Foundation software is covered by
  18 the GNU Library General Public License instead.)  You can apply it to
  19 your programs, too.
  20
  21   When we speak of free software, we are referring to freedom, not
  22 price.  Our General Public Licenses are designed to make sure that you
  23 have the freedom to distribute copies of free software (and charge for
  24 this service if you wish), that you receive source code or can get it
  25 if you want it, that you can change the software or use pieces of it
  26 in new free programs; and that you know you can do these things.
  27
  28   To protect your rights, we need to make restrictions that forbid
  29 anyone to deny you these rights or to ask you to surrender the rights.
  30 These restrictions translate to certain responsibilities for you if you
  31 distribute copies of the software, or if you modify it.
  32
  33   For example, if you distribute copies of such a program, whether
  34 gratis or for a fee, you must give the recipients all the rights that
  35 you have.  You must make sure that they, too, receive or can get the
  36 source code.  And you must show them these terms so they know their
  37 rights.
  38
  39   We protect your rights with two steps: (1) copyright the software, and
  40 (2) offer you this license which gives you legal permission to copy,
  41 distribute and/or modify the software.
  42
  43   Also, for each author's protection and ours, we want to make certain
  44 that everyone understands that there is no warranty for this free
  45 software.  If the software is modified by someone else and passed on, we
  46 want its recipients to know that what they have is not the original, so
  47 that any problems introduced by others will not reflect on the original
  48 authors' reputations.
  49
  50   Finally, any free program is threatened constantly by software
  51 patents.  We wish to avoid the danger that redistributors of a free
  52 program will individually obtain patent licenses, in effect making the
  53 program proprietary.  To prevent this, we have made it clear that any
  54 patent must be licensed for everyone's free use or not licensed at all.
  55
  56   The precise terms and conditions for copying, distribution and
  57 modification follow.
  58
  59
  60                     GNU GENERAL PUBLIC LICENSE
  61    TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
  62
  63   0. This License applies to any program or other work which contains
  64 a notice placed by the copyright holder saying it may be distributed
  65 under the terms of this General Public License.  The "Program", below,
  66 refers to any such program or work, and a "work based on the Program"
  67 means either the Program or any derivative work under copyright law:
  68 that is to say, a work containing the Program or a portion of it,
  69 either verbatim or with modifications and/or translated into another
  70 language.  (Hereinafter, translation is included without limitation in
  71 the term "modification".)  Each licensee is addressed as "you".
  72
  73 Activities other than copying, distribution and modification are not
  74 covered by this License; they are outside its scope.  The act of
  75 running the Program is not restricted, and the output from the Program
  76 is covered only if its contents constitute a work based on the
  77 Program (independent of having been made by running the Program).
  78 Whether that is true depends on what the Program does.
  79
  80   1. You may copy and distribute verbatim copies of the Program's
  81 source code as you receive it, in any medium, provided that you
  82 conspicuously and appropriately publish on each copy an appropriate
  83 copyright notice and disclaimer of warranty; keep intact all the
  84 notices that refer to this License and to the absence of any warranty;
  85 and give any other recipients of the Program a copy of this License
  86 along with the Program.
  87
  88 You may charge a fee for the physical act of transferring a copy, and
  89 you may at your option offer warranty protection in exchange for a fee.
  90
  91   2. You may modify your copy or copies of the Program or any portion
  92 of it, thus forming a work based on the Program, and copy and
  93 distribute such modifications or work under the terms of Section 1
  94 above, provided that you also meet all of these conditions:
  95
  96     a) You must cause the modified files to carry prominent notices
  97     stating that you changed the files and the date of any change.
  98
  99     b) You must cause any work that you distribute or publish, that in
 100     whole or in part contains or is derived from the Program or any
 101     part thereof, to be licensed as a whole at no charge to all third
 102     parties under the terms of this License.
 103
 104     c) If the modified program normally reads commands interactively
 105     when run, you must cause it, when started running for such
 106     interactive use in the most ordinary way, to print or display an
 107     announcement including an appropriate copyright notice and a
 108     notice that there is no warranty (or else, saying that you provide
 109     a warranty) and that users may redistribute the program under
 110     these conditions, and telling the user how to view a copy of this
 111     License.  (Exception: if the Program itself is interactive but
 112     does not normally print such an announcement, your work based on
 113     the Program is not required to print an announcement.)
 114
 115
 116 These requirements apply to the modified work as a whole.  If
 117 identifiable sections of that work are not derived from the Program,
 118 and can be reasonably considered independent and separate works in
 119 themselves, then this License, and its terms, do not apply to those
 120 sections when you distribute them as separate works.  But when you
 121 distribute the same sections as part of a whole which is a work based
 122 on the Program, the distribution of the whole must be on the terms of
 123 this License, whose permissions for other licensees extend to the
 124 entire whole, and thus to each and every part regardless of who wrote it.
 125
 126 Thus, it is not the intent of this section to claim rights or contest
 127 your rights to work written entirely by you; rather, the intent is to
 128 exercise the right to control the distribution of derivative or
 129 collective works based on the Program.
 130
 131 In addition, mere aggregation of another work not based on the Program
 132 with the Program (or with a work based on the Program) on a volume of
 133 a storage or distribution medium does not bring the other work under
 134 the scope of this License.
 135
 136   3. You may copy and distribute the Program (or a work based on it,
 137 under Section 2) in object code or executable form under the terms of
 138 Sections 1 and 2 above provided that you also do one of the following:
 139
 140     a) Accompany it with the complete corresponding machine-readable
 141     source code, which must be distributed under the terms of Sections
 142     1 and 2 above on a medium customarily used for software interchange; or,
 143
 144     b) Accompany it with a written offer, valid for at least three
 145     years, to give any third party, for a charge no more than your
 146     cost of physically performing source distribution, a complete
 147     machine-readable copy of the corresponding source code, to be
 148     distributed under the terms of Sections 1 and 2 above on a medium
 149     customarily used for software interchange; or,
 150
 151     c) Accompany it with the information you received as to the offer
 152     to distribute corresponding source code.  (This alternative is
 153     allowed only for noncommercial distribution and only if you
 154     received the program in object code or executable form with such
 155     an offer, in accord with Subsection b above.)
 156
 157 The source code for a work means the preferred form of the work for
 158 making modifications to it.  For an executable work, complete source
 159 code means all the source code for all modules it contains, plus any
 160 associated interface definition files, plus the scripts used to
 161 control compilation and installation of the executable.  However, as a
 162 special exception, the source code distributed need not include
 163 anything that is normally distributed (in either source or binary
 164 form) with the major components (compiler, kernel, and so on) of the
 165 operating system on which the executable runs, unless that component
 166 itself accompanies the executable.
 167
 168 If distribution of executable or object code is made by offering
 169 access to copy from a designated place, then offering equivalent
 170 access to copy the source code from the same place counts as
 171 distribution of the source code, even though third parties are not
 172 compelled to copy the source along with the object code.
 173
 174
 175   4. You may not copy, modify, sublicense, or distribute the Program
 176 except as expressly provided under this License.  Any attempt
 177 otherwise to copy, modify, sublicense or distribute the Program is
 178 void, and will automatically terminate your rights under this License.
 179 However, parties who have received copies, or rights, from you under
 180 this License will not have their licenses terminated so long as such
 181 parties remain in full compliance.
 182
 183   5. You are not required to accept this License, since you have not
 184 signed it.  However, nothing else grants you permission to modify or
 185 distribute the Program or its derivative works.  These actions are
 186 prohibited by law if you do not accept this License.  Therefore, by
 187 modifying or distributing the Program (or any work based on the
 188 Program), you indicate your acceptance of this License to do so, and
 189 all its terms and conditions for copying, distributing or modifying
 190 the Program or works based on it.
 191
 192   6. Each time you redistribute the Program (or any work based on the
 193 Program), the recipient automatically receives a license from the
 194 original licensor to copy, distribute or modify the Program subject to
 195 these terms and conditions.  You may not impose any further
 196 restrictions on the recipients' exercise of the rights granted herein.
 197 You are not responsible for enforcing compliance by third parties to
 198 this License.
 199
 200   7. If, as a consequence of a court judgment or allegation of patent
 201 infringement or for any other reason (not limited to patent issues),
 202 conditions are imposed on you (whether by court order, agreement or
 203 otherwise) that contradict the conditions of this License, they do not
 204 excuse you from the conditions of this License.  If you cannot
 205 distribute so as to satisfy simultaneously your obligations under this
 206 License and any other pertinent obligations, then as a consequence you
 207 may not distribute the Program at all.  For example, if a patent
 208 license would not permit royalty-free redistribution of the Program by
 209 all those who receive copies directly or indirectly through you, then
 210 the only way you could satisfy both it and this License would be to
 211 refrain entirely from distribution of the Program.
 212
 213 If any portion of this section is held invalid or unenforceable under
 214 any particular circumstance, the balance of the section is intended to
 215 apply and the section as a whole is intended to apply in other
 216 circumstances.
 217
 218 It is not the purpose of this section to induce you to infringe any
 219 patents or other property right claims or to contest validity of any
 220 such claims; this section has the sole purpose of protecting the
 221 integrity of the free software distribution system, which is
 222 implemented by public license practices.  Many people have made
 223 generous contributions to the wide range of software distributed
 224 through that system in reliance on consistent application of that
 225 system; it is up to the author/donor to decide if he or she is willing
 226 to distribute software through any other system and a licensee cannot
 227 impose that choice.
 228
 229 This section is intended to make thoroughly clear what is believed to
 230 be a consequence of the rest of this License.
 231
 232
 233   8. If the distribution and/or use of the Program is restricted in
 234 certain countries either by patents or by copyrighted interfaces, the
 235 original copyright holder who places the Program under this License
 236 may add an explicit geographical distribution limitation excluding
 237 those countries, so that distribution is permitted only in or among
 238 countries not thus excluded.  In such case, this License incorporates
 239 the limitation as if written in the body of this License.
 240
 241   9. The Free Software Foundation may publish revised and/or new versions
 242 of the General Public License from time to time.  Such new versions will
 243 be similar in spirit to the present version, but may differ in detail to
 244 address new problems or concerns.
 245
 246 Each version is given a distinguishing version number.  If the Program
 247 specifies a version number of this License which applies to it and "any
 248 later version", you have the option of following the terms and conditions
 249 either of that version or of any later version published by the Free
 250 Software Foundation.  If the Program does not specify a version number of
 251 this License, you may choose any version ever published by the Free Software
 252 Foundation.
 253
 254   10. If you wish to incorporate parts of the Program into other free
 255 programs whose distribution conditions are different, write to the author
 256 to ask for permission.  For software which is copyrighted by the Free
 257 Software Foundation, write to the Free Software Foundation; we sometimes
 258 make exceptions for this.  Our decision will be guided by the two goals
 259 of preserving the free status of all derivatives of our free software and
 260 of promoting the sharing and reuse of software generally.
 261
 262                             NO WARRANTY
 263
 264   11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
 265 FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
 266 OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
 267 PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
 268 OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 269 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
 270 TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
 271 PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
 272 REPAIR OR CORRECTION.
 273
 274   12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
 275 WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
 276 REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
 277 INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
 278 OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
 279 TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
 280 YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
 281 PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
 282 POSSIBILITY OF SUCH DAMAGES.
 283
 284                      END OF TERMS AND CONDITIONS
 285
 286
 287             How to Apply These Terms to Your New Programs
 288
 289   If you develop a new program, and you want it to be of the greatest
 290 possible use to the public, the best way to achieve this is to make it
 291 free software which everyone can redistribute and change under these terms.
 292
 293   To do so, attach the following notices to the program.  It is safest
 294 to attach them to the start of each source file to most effectively
 295 convey the exclusion of warranty; and each file should have at least
 296 the "copyright" line and a pointer to where the full notice is found.
 297
 298     <one line to give the program's name and a brief idea of what it does.>
 299     Copyright (C) <year>  <name of author>
 300
 301     This program is free software; you can redistribute it and/or modify
 302     it under the terms of the GNU General Public License as published by
 303     the Free Software Foundation; either version 2 of the License, or
 304     (at your option) any later version.
 305
 306     This program is distributed in the hope that it will be useful,
 307     but WITHOUT ANY WARRANTY; without even the implied warranty of
 308     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 309     GNU General Public License for more details.
 310
 311     You should have received a copy of the GNU General Public License
 312     along with this program; if not, write to the Free Software
 313     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 314
 315
 316 Also add information on how to contact you by electronic and paper mail.
 317
 318 If the program is interactive, make it output a short notice like this
 319 when it starts in an interactive mode:
 320
 321     Gnomovision version 69, Copyright (C) year name of author
 322     Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
 323     This is free software, and you are welcome to redistribute it
 324     under certain conditions; type `show c' for details.
 325
 326 The hypothetical commands `show w' and `show c' should show the appropriate
 327 parts of the General Public License.  Of course, the commands you use may
 328 be called something other than `show w' and `show c'; they could even be
 329 mouse-clicks or menu items--whatever suits your program.
 330
 331 You should also get your employer (if you work as a programmer) or your
 332 school, if any, to sign a "copyright disclaimer" for the program, if
 333 necessary.  Here is a sample; alter the names:
 334
 335   Yoyodyne, Inc., hereby disclaims all copyright interest in the program
 336   `Gnomovision' (which makes passes at compilers) written by James Hacker.
 337
 338   <signature of Ty Coon>, 1 April 1989
 339   Ty Coon, President of Vice
 340
 341 This General Public License does not permit incorporating your program into
 342 proprietary programs.  If your program is a subroutine library, you may
 343 consider it more useful to permit linking proprietary applications with the
 344 library.  If this is what you want to do, use the GNU Library General
 345 Public License instead of this License.