1libjpeg-turbo Licenses
2======================
3
4libjpeg-turbo is covered by three compatible BSD-style open source licenses:
5
6- The IJG (Independent JPEG Group) License, which is listed in
7  [README.ijg](README.ijg)
8
9  This license applies to the libjpeg API library and associated programs
10  (any code inherited from libjpeg, and any modifications to that code.)
11
12- The Modified (3-clause) BSD License, which is listed below
13
14  This license covers the TurboJPEG API library and associated programs, as
15  well as the build system.
16
17- The [zlib License](https://opensource.org/licenses/Zlib)
18
19  This license is a subset of the other two, and it covers the libjpeg-turbo
20  SIMD extensions.
21
22
23Complying with the libjpeg-turbo Licenses
24=========================================
25
26This section provides a roll-up of the libjpeg-turbo licensing terms, to the
27best of our understanding.
28
291.  If you are distributing a modified version of the libjpeg-turbo source,
30    then:
31
32    1.  You cannot alter or remove any existing copyright or license notices
33        from the source.
34
35        **Origin**
36        - Clause 1 of the IJG License
37        - Clause 1 of the Modified BSD License
38        - Clauses 1 and 3 of the zlib License
39
40    2.  You must add your own copyright notice to the header of each source
41        file you modified, so others can tell that you modified that file (if
42        there is not an existing copyright header in that file, then you can
43        simply add a notice stating that you modified the file.)
44
45        **Origin**
46        - Clause 1 of the IJG License
47        - Clause 2 of the zlib License
48
49    3.  You must include the IJG README file, and you must not alter any of the
50        copyright or license text in that file.
51
52        **Origin**
53        - Clause 1 of the IJG License
54
552.  If you are distributing only libjpeg-turbo binaries without the source, or
56    if you are distributing an application that statically links with
57    libjpeg-turbo, then:
58
59    1.  Your product documentation must include a message stating:
60
61        This software is based in part on the work of the Independent JPEG
62        Group.
63
64        **Origin**
65        - Clause 2 of the IJG license
66
67    2.  If your binary distribution includes or uses the TurboJPEG API, then
68        your product documentation must include the text of the Modified BSD
69        License (see below.)
70
71        **Origin**
72        - Clause 2 of the Modified BSD License
73
743.  You cannot use the name of the IJG or The libjpeg-turbo Project or the
75    contributors thereof in advertising, publicity, etc.
76
77    **Origin**
78    - IJG License
79    - Clause 3 of the Modified BSD License
80
814.  The IJG and The libjpeg-turbo Project do not warrant libjpeg-turbo to be
82    free of defects, nor do we accept any liability for undesirable
83    consequences resulting from your use of the software.
84
85    **Origin**
86    - IJG License
87    - Modified BSD License
88    - zlib License
89
90
91The Modified (3-clause) BSD License
92===================================
93
94Copyright (C)2009-2021 D. R. Commander.  All Rights Reserved.<br>
95Copyright (C)2015 Viktor Szathmáry.  All Rights Reserved.
96
97Redistribution and use in source and binary forms, with or without
98modification, are permitted provided that the following conditions are met:
99
100- Redistributions of source code must retain the above copyright notice,
101  this list of conditions and the following disclaimer.
102- Redistributions in binary form must reproduce the above copyright notice,
103  this list of conditions and the following disclaimer in the documentation
104  and/or other materials provided with the distribution.
105- Neither the name of the libjpeg-turbo Project nor the names of its
106  contributors may be used to endorse or promote products derived from this
107  software without specific prior written permission.
108
109THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS",
110AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
111IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
112ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
113LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
114CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
115SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
116INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
117CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
118ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
119POSSIBILITY OF SUCH DAMAGE.
120
121
122Why Three Licenses?
123===================
124
125The zlib License could have been used instead of the Modified (3-clause) BSD
126License, and since the IJG License effectively subsumes the distribution
127conditions of the zlib License, this would have effectively placed
128libjpeg-turbo binary distributions under the IJG License.  However, the IJG
129License specifically refers to the Independent JPEG Group and does not extend
130attribution and endorsement protections to other entities.  Thus, it was
131desirable to choose a license that granted us the same protections for new code
132that were granted to the IJG for code derived from their software.
133