[lib]uvco (c) 2023 Lewin Bormann

Licensed under the terms of the GNU LGPL 2.1:

PREAMBLE

The licenses for most software are designed to take away your freedom to share
and change it. By contrast, the GNU General Public Licenses are intended to
guarantee your freedom to share and change free software–to make sure the
software is free for all its users.

This license, the Lesser General Public License, applies to some specially
designated software packages–typically libraries–of the Free Software
Foundation and other authors who decide to use it. You can use it too, but we
suggest you first think carefully about whether this license or the ordinary
General Public License is the better strategy to use in any particular case,
based on the explanations below.

When we speak of free software, we are referring to freedom of use, 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 and use pieces
of it in new free programs; and that you are informed that you can do
these things.

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

For example, if you distribute copies of the library, whether gratis or
for a fee, you must give the recipients all the rights that we gave
you. You must make sure that they, too, receive or can get the source
code. If you link other code with the library, you must provide
complete object files to the recipients, so that they can relink them
with the library after making changes to the library and recompiling
it. And you must show them these terms so they know their rights.

We protect your rights with a two-step method: (1) we copyright the
library, and (2) we offer you this license, which gives you legal
permission to copy, distribute and/or modify the library.

To protect each distributor, we want to make it very clear that there
is no warranty for the free library. Also, if the library is modified
by someone else and passed on, the recipients should know that what
they have is not the original version, so that the original author’s
reputation will not be affected by problems that might be introduced by
others.

Finally, software patents pose a constant threat to the existence of
any free program. We wish to make sure that a company cannot
effectively restrict the users of a free program by obtaining a
restrictive license from a patent holder. Therefore, we insist that any
patent license obtained for a version of the library must be consistent
with the full freedom of use specified in this license.

Most GNU software, including some libraries, is covered by the ordinary
GNU General Public License. This license, the GNU Lesser General Public
License, applies to certain designated libraries, and is quite
different from the ordinary General Public License. We use this license
for certain libraries in order to permit linking those libraries into
non-free programs.

When a program is linked with a library, whether statically or using a
shared library, the combination of the two is legally speaking a
combined work, a derivative of the original library. The ordinary
General Public License therefore permits such linking only if the
entire combination fits its criteria of freedom. The Lesser General
Public License permits more lax criteria for linking other code with
the library.

We call this license the “Lesser” General Public License because it
does Less to protect the user’s freedom than the ordinary General
Public License. It also provides other free software developers Less of
an advantage over competing non-free programs. These disadvantages are
the reason we use the ordinary General Public License for many
libraries. However, the Lesser license provides advantages in certain
special circumstances.

For example, on rare occasions, there may be a special need to
encourage the widest possible use of a certain library, so that it
becomes a de-facto standard. To achieve this, non-free programs must be
allowed to use the library. A more frequent case is that a free library
does the same job as widely used non-free libraries. In this case,
there is little to gain by limiting the free library to free software
only, so we use the Lesser General Public License.

In other cases, permission to use a particular library in non-free
programs enables a greater number of people to use a large body of free
software. For example, permission to use the GNU C Library in non-free
programs enables many more people to use the whole GNU operating
system, as well as its variant, the GNU/Linux operating system.

Although the Lesser General Public License is Less protective of the
users’ freedom, it does ensure that the user of a program that is
linked with the Library has the freedom and the wherewithal to run that
program using a modified version of the Library.

The precise terms and conditions for copying, distribution and
modification follow. Pay close attention to the difference between a
“work based on the library” and a “work that uses the library”. The
former contains code derived from the library, whereas the latter must
be combined with the library in order to run. TERMS AND CONDITIONS FOR
COPYING, DISTRIBUTION AND MODIFICATION

0. This License Agreement applies to any software library or other
program which contains a notice placed by the copyright holder or other
authorized party saying it may be distributed under the terms of this
Lesser General Public License (also called “this License”). Each
licensee is addressed as “you”.

A “library” means a collection of software functions and/or data
prepared so as to be conveniently linked with application programs
(which use some of those functions and data) to form executables.

The “Library”, below, refers to any such software library or work which
has been distributed under these terms. A “work based on the Library”
means either the Library or any derivative work under copyright law:
that is to say, a work containing the Library or a portion of it, either
verbatim or with modifications and/or translated straightforwardly into another
language. (Hereinafter, translation is included without limitation in the term
“modification”.)

“Source code” for a work means the preferred form of the work for making
modifications to it. For a library, 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
library.

Activities other than copying, distribution and modification are not covered by
this License; they are outside its scope. The act of running a program using
the Library is not restricted, and output from such a program is covered only
if its contents constitute a work based on the Library (independent of the use
of the Library in a tool for writing it). Whether that is true depends
on what the Library does and what the program that uses the Library does.

1. You may copy and distribute verbatim copies of the Library’s complete 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 distribute a copy of this License along
with the Library.

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 Library or any portion of it, thus
forming a work based on the Library, 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) The modified work must itself be a software library.

b) You must cause the files modified to carry prominent notices stating that
you changed the files and the date of any change.

c) You must cause the whole of the work to be licensed at no charge to all
third parties under the terms of this License.

d) If a facility in the modified Library refers to a function or a table of
data to be supplied by an application program that uses the facility, other
than as an argument passed when the facility is invoked, then you must make a
good faith effort to ensure that, in the event an application does not supply
such function or table, the facility still operates, and performs whatever part
of its purpose remains meaningful.

(For example, a function in a library to compute square roots has a purpose
that is entirely well-defined independent of the application. Therefore,
Subsection 2d requires that any application-supplied function or table used by
this function must be optional: if the application does not supply it, the
square root function must still compute square roots.)

These requirements apply to the modified work as a whole. If identifiable
sections of that work are not derived from the Library, 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 Library, 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 Library.

In addition, mere aggregation of another work not based on the Library with the
Library (or with a work based on the Library) on a volume of a storage or
distribution medium does not bring the other work under the scope of this
License.

3. You may opt to apply the terms of the ordinary GNU General Public License
instead of this License to a given copy of the Library. To do this, you must
alter all the notices that refer to this License, so that they refer to the
ordinary GNU General Public License, version 2, instead of to this License. (If
a newer version than version 2 of the ordinary GNU General Public
License has appeared, then you can specify that version instead if you
wish.) Do not make any other change in these notices.

Once this change is made in a given copy, it is irreversible for that copy, so
the ordinary GNU General Public License applies to all subsequent copies and
derivative works made from that copy.

This option is useful when you wish to copy part of the code of the Library
into a program that is not a library.

4. You may copy and distribute the Library (or a portion or derivative of it,
under Section 2) in object code or executable form under the terms of
Sections 1 and 2 above provided that you 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.

If distribution of 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 satisfies the requirement to distribute the source code, even
though third parties are not compelled to copy the source along with the object
code.

5. A program that contains no derivative of any portion of the Library, but is
designed to work with the Library by being compiled or linked with it, is
called a “work that uses the Library”. Such a work, in isolation, is not a
derivative work of the Library, and therefore falls outside the scope of this
License.

However, linking a “work that uses the Library” with the Library creates an
executable that is a derivative of the Library (because it contains portions of
the Library), rather than a “work that uses the library”. The
executable is therefore covered by this License. Section 6 states terms for
distribution of such executables.

When a “work that uses the Library” uses material from a header file that is
part of the Library, the object code for the work may be a derivative work of
the Library even though the source code is not. Whether this is true is
especially significant if the work can be linked without the Library, or if the
work is itself a library. The threshold for this to be true is not precisely
defined by law.

If such an object file uses only numerical parameters, data structure layouts
and accessors, and small macros and small inline functions (ten lines or less
in length), then the use of the object file is unrestricted, regardless
of whether it is legally a derivative work. (Executables containing this object
code plus portions of the Library will still fall under Section 6.)

Otherwise, if the work is a derivative of the Library, you may distribute the
object code for the work under the terms of Section 6. Any executables
containing that work also fall under Section 6, whether or not they are linked
directly with the Library itself.

6. As an exception to the Sections above, you may also combine or link a “work
that uses the Library” with the Library to produce a work containing portions
of the Library, and distribute that work under terms of your choice, provided
that the terms permit modification of the work for the customer’s own use and
reverse engineering for debugging such modifications.

You must give prominent notice with each copy of the work that the Library is
used in it and that the Library and its use are covered by this License. You
must supply a copy of this License. If the work during execution displays
copyright notices, you must include the copyright notice for the Library among
them, as well as a reference directing the user to the copy of this License.
Also, you must do one of these things:

a) Accompany the work with the complete corresponding machine-readable source
code for the Library including whatever changes were used in the work (which
must be distributed under Sections 1 and 2 above); and, if the work is
an executable linked with the Library, with the complete machine-readable “work
that uses the Library”, as object code and/or source code, so that the user can
modify the Library and then relink to produce a modified executable containing
the modified Library. (It is understood that the user who changes the contents
of definitions files in the Library will not necessarily be able to
recompile the application to use the modified definitions.)

b) Use a suitable shared library mechanism for linking with the Library. A
suitable mechanism is one that (1) uses at run time a copy of the library
already present on the user’s computer system, rather than copying library
functions into the executable, and (2) will operate properly with a modified
version of the library, if the user installs one, as long as the modified
version is interface-compatible with the version that the work was made with.

c) Accompany the work with a written offer, valid for at least three years, to
give the same user the materials specified in Subsection 6a, above, for a
charge no more than the cost of performing this distribution.

d) If distribution of the work is made by offering access to copy from a
designated place, offer equivalent access to copy the above specified materials
from the same place.

e) Verify that the user has already received a copy of these materials or that
you have already sent this user a copy.

For an executable, the required form of the “work that uses the Library” must
include any data and utility programs needed for reproducing the executable
from it. However, as a special exception, the materials to be 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.

It may happen that this requirement contradicts the license restrictions of
other proprietary libraries that do not normally accompany the operating
system. Such a contradiction means you cannot use both them and the Library
together in an executable that you distribute.

7. You may place library facilities that are a work based on the Library
side-by-side in a single library together with other library facilities not
covered by this License, and distribute such a combined library, provided that
the separate distribution of the work based on the Library and of the other
library facilities is otherwise permitted, and provided that you do these two
things:

a) Accompany the combined library with a copy of the same work based on the
Library, uncombined with any other library facilities. This must be distributed
under the terms of the Sections above.

b) Give prominent notice with the combined library of the fact that part of it
is a work based on the Library, and explaining where to find the accompanying
uncombined form of the same work.

8. You may not copy, modify, sublicense, link with, or distribute the Library
except as expressly provided under this License. Any attempt otherwise to copy,
modify, sublicense, link with, or distribute the Library 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.

9. 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 Library or its derivative works. These actions are
prohibited by law if you do not accept this License. Therefore, by
modifying or distributing the Library (or any work based on the
       Library), you indicate your acceptance of this License to do so,
and all its terms and conditions for copying, distributing or modifying
the Library or works based on it.

10. Each time you redistribute the Library (or any work based on the
       Library), the recipient automatically receives a license from
the original licensor to copy, distribute, link with or modify the
Library 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 with this License.

11. 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 Library at all. For example, if a patent license
would not permit royalty-free redistribution of the Library 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 Library.

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.

12. If the distribution and/or use of the Library is restricted in
certain countries either by patents or by copyrighted interfaces, the
original copyright holder who places the Library 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.

13. The Free Software Foundation may publish revised and/or new versions
of the Lesser 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 Library
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 Library does not specify a license
version number, you may choose any version ever published by the Free
Software Foundation.

14. If you wish to incorporate parts of the Library into other free
programs whose distribution conditions are incompatible with these,
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

15. BECAUSE THE LIBRARY IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
FOR THE LIBRARY, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
PROVIDE THE LIBRARY “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 LIBRARY IS WITH
YOU. SHOULD THE LIBRARY PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL
NECESSARY SERVICING, REPAIR OR CORRECTION.

16. 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 LIBRARY 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 LIBRARY
(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 LIBRARY TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF SUCH HOLDER OR
OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
