Finally, any free program is threatened constantly by soft-
ware patents. We wish to avoid the danger that redistrib-
utors 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, distribu-
tion and modification follow.
GNU GENERAL PUBLIC LICENSE
TERMS AND CONDITIONS FOR COPY-
ING, DISTRIBUTION AND MODIFICA-
TION
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 Gen-
eral Public License. The "Program", below, refers to any
such program or work, and a "work based on the Pro-
gram" 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 modifi-
cations and/or translated into another language. (Herein-
after, translation is included without limitation in the
term "modification".) Each licensee is addressed as "you".
Activities other than copying, distribution and modifica-
tion 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 (inde-
pendent 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 pub-
lish 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 discretion, offer warranty pro-
tection 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 Pro-
gram, 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 promi-
nent 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 run-
ning is commenced for such interactive use in the
most ordinary way, to print or display an announce-
ment 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 redistrib-
ute the program under these conditions, and telling
the user how to view a copy of this License. (Excep-
tion: 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 independ-
ent 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 distrib-
ute 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 dis-
tributed under the terms of Sections 1 and 2 above
on a medium customarily used for software inter-
change; 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 compila-
tion and installation of the executable. However, as a spe-
cial exception, the source code distributed need not
include anything that is normally distributed (in either
source or binary form) with the major components (com-
piler, kernel, and so on) of the operating system on which
the executable runs, unless that component itself accom-
panies 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 dis-
tribute the Program is void, and will automatically termi-
nate 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 per-
mission to modify or distribute the Program or its deriva-
tive works. These actions are prohibited by law if you do
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