Adopt REUSE machine-readable licensing standard

44 files changed, 238 insertions, 556 deletions

diff --git a/.reuse/dep5 b/.reuse/dep5
new file mode 100644
index 0000000..2a2810b
--- /dev/null
+++ b/.reuse/dep5
@@ -0,0 +1,12 @@
+Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
+Upstream-Name: zix
+Upstream-Contact: David Robillard <d@drobilla.net>
+Source: https://gitlab.com/drobilla/zix
+
+Files: *.md .clang* .git* NEWS meson_options.txt */.clang* .clant.json .includes.imp
+Copyright: 2021 David Robillard <d@drobilla.net>
+License: CC0-1.0 OR ISC
+
+Files: doc/*
+Copyright: 2021 David Robillard <d@drobilla.net>
+License: CC0-1.0 OR ISC
diff --git a/COPYING b/COPYING
index 63e6829..16fec11 100644
--- a/COPYING
+++ b/COPYING
@@ -1,4 +1,4 @@
-Copyright 2011-2020 David Robillard <d@drobilla.net>
+Copyright 2011-2021 David Robillard <d@drobilla.net>
 
 Permission to use, copy, modify, and/or distribute this software for any
 purpose with or without fee is hereby granted, provided that the above
diff --git a/LICENSES/CC0-1.0.txt b/LICENSES/CC0-1.0.txt
new file mode 100644
index 0000000..0e259d4
--- /dev/null
+++ b/LICENSES/CC0-1.0.txt
@@ -0,0 +1,121 @@
+Creative Commons Legal Code
+
+CC0 1.0 Universal
+
+    CREATIVE COMMONS CORPORATION IS NOT A LAW FIRM AND DOES NOT PROVIDE
+    LEGAL SERVICES. DISTRIBUTION OF THIS DOCUMENT DOES NOT CREATE AN
+    ATTORNEY-CLIENT RELATIONSHIP. CREATIVE COMMONS PROVIDES THIS
+    INFORMATION ON AN "AS-IS" BASIS. CREATIVE COMMONS MAKES NO WARRANTIES
+    REGARDING THE USE OF THIS DOCUMENT OR THE INFORMATION OR WORKS
+    PROVIDED HEREUNDER, AND DISCLAIMS LIABILITY FOR DAMAGES RESULTING FROM
+    THE USE OF THIS DOCUMENT OR THE INFORMATION OR WORKS PROVIDED
+    HEREUNDER.
+
+Statement of Purpose
+
+The laws of most jurisdictions throughout the world automatically confer
+exclusive Copyright and Related Rights (defined below) upon the creator
+and subsequent owner(s) (each and all, an "owner") of an original work of
+authorship and/or a database (each, a "Work").
+
+Certain owners wish to permanently relinquish those rights to a Work for
+the purpose of contributing to a commons of creative, cultural and
+scientific works ("Commons") that the public can reliably and without fear
+of later claims of infringement build upon, modify, incorporate in other
+works, reuse and redistribute as freely as possible in any form whatsoever
+and for any purposes, including without limitation commercial purposes.
+These owners may contribute to the Commons to promote the ideal of a free
+culture and the further production of creative, cultural and scientific
+works, or to gain reputation or greater distribution for their Work in
+part through the use and efforts of others.
+
+For these and/or other purposes and motivations, and without any
+expectation of additional consideration or compensation, the person
+associating CC0 with a Work (the "Affirmer"), to the extent that he or she
+is an owner of Copyright and Related Rights in the Work, voluntarily
+elects to apply CC0 to the Work and publicly distribute the Work under its
+terms, with knowledge of his or her Copyright and Related Rights in the
+Work and the meaning and intended legal effect of CC0 on those rights.
+
+1. Copyright and Related Rights. A Work made available under CC0 may be
+protected by copyright and related or neighboring rights ("Copyright and
+Related Rights"). Copyright and Related Rights include, but are not
+limited to, the following:
+
+  i. the right to reproduce, adapt, distribute, perform, display,
+     communicate, and translate a Work;
+ ii. moral rights retained by the original author(s) and/or performer(s);
+iii. publicity and privacy rights pertaining to a person's image or
+     likeness depicted in a Work;
+ iv. rights protecting against unfair competition in regards to a Work,
+     subject to the limitations in paragraph 4(a), below;
+  v. rights protecting the extraction, dissemination, use and reuse of data
+     in a Work;
+ vi. database rights (such as those arising under Directive 96/9/EC of the
+     European Parliament and of the Council of 11 March 1996 on the legal
+     protection of databases, and under any national implementation
+     thereof, including any amended or successor version of such
+     directive); and
+vii. other similar, equivalent or corresponding rights throughout the
+     world based on applicable law or treaty, and any national
+     implementations thereof.
+
+2. Waiver. To the greatest extent permitted by, but not in contravention
+of, applicable law, Affirmer hereby overtly, fully, permanently,
+irrevocably and unconditionally waives, abandons, and surrenders all of
+Affirmer's Copyright and Related Rights and associated claims and causes
+of action, whether now known or unknown (including existing as well as
+future claims and causes of action), in the Work (i) in all territories
+worldwide, (ii) for the maximum duration provided by applicable law or
+treaty (including future time extensions), (iii) in any current or future
+medium and for any number of copies, and (iv) for any purpose whatsoever,
+including without limitation commercial, advertising or promotional
+purposes (the "Waiver"). Affirmer makes the Waiver for the benefit of each
+member of the public at large and to the detriment of Affirmer's heirs and
+successors, fully intending that such Waiver shall not be subject to
+revocation, rescission, cancellation, termination, or any other legal or
+equitable action to disrupt the quiet enjoyment of the Work by the public
+as contemplated by Affirmer's express Statement of Purpose.
+
+3. Public License Fallback. Should any part of the Waiver for any reason
+be judged legally invalid or ineffective under applicable law, then the
+Waiver shall be preserved to the maximum extent permitted taking into
+account Affirmer's express Statement of Purpose. In addition, to the
+extent the Waiver is so judged Affirmer hereby grants to each affected
+person a royalty-free, non transferable, non sublicensable, non exclusive,
+irrevocable and unconditional license to exercise Affirmer's Copyright and
+Related Rights in the Work (i) in all territories worldwide, (ii) for the
+maximum duration provided by applicable law or treaty (including future
+time extensions), (iii) in any current or future medium and for any number
+of copies, and (iv) for any purpose whatsoever, including without
+limitation commercial, advertising or promotional purposes (the
+"License"). The License shall be deemed effective as of the date CC0 was
+applied by Affirmer to the Work. Should any part of the License for any
+reason be judged legally invalid or ineffective under applicable law, such
+partial invalidity or ineffectiveness shall not invalidate the remainder
+of the License, and in such case Affirmer hereby affirms that he or she
+will not (i) exercise any of his or her remaining Copyright and Related
+Rights in the Work or (ii) assert any associated claims and causes of
+action with respect to the Work, in either case contrary to Affirmer's
+express Statement of Purpose.
+
+4. Limitations and Disclaimers.
+
+ a. No trademark or patent rights held by Affirmer are waived, abandoned,
+    surrendered, licensed or otherwise affected by this document.
+ b. Affirmer offers the Work as-is and makes no representations or
+    warranties of any kind concerning the Work, express, implied,
+    statutory or otherwise, including without limitation warranties of
+    title, merchantability, fitness for a particular purpose, non
+    infringement, or the absence of latent or other defects, accuracy, or
+    the present or absence of errors, whether or not discoverable, all to
+    the greatest extent permissible under applicable law.
+ c. Affirmer disclaims responsibility for clearing rights of other persons
+    that may apply to the Work or any use thereof, including without
+    limitation any person's Copyright and Related Rights in the Work.
+    Further, Affirmer disclaims responsibility for obtaining any necessary
+    consents, permissions or other rights required for any use of the
+    Work.
+ d. Affirmer understands and acknowledges that Creative Commons is not a
+    party to this document and has no duty or obligation with respect to
+    this CC0 or use of the Work.
diff --git a/LICENSES/ISC.txt b/LICENSES/ISC.txt
new file mode 100644
index 0000000..16fec11
--- /dev/null
+++ b/LICENSES/ISC.txt
@@ -0,0 +1,13 @@
+Copyright 2011-2021 David Robillard <d@drobilla.net>
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/benchmark/bench.h b/benchmark/bench.h
index 3cc44ee..c07e211 100644
--- a/benchmark/bench.h
+++ b/benchmark/bench.h
@@ -1,18 +1,5 @@
-/*
-  Copyright 2011-2020 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2011-2020 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #ifndef BENCH_H
 #define BENCH_H
diff --git a/benchmark/dict_bench.c b/benchmark/dict_bench.c
index cd358a3..30f485f 100644
--- a/benchmark/dict_bench.c
+++ b/benchmark/dict_bench.c
@@ -1,18 +1,5 @@
-/*
-  Copyright 2011-2021 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2011-2021 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #include "bench.h"
 #include "warnings.h"
diff --git a/benchmark/tree_bench.c b/benchmark/tree_bench.c
index b55d772..0f54f65 100644
--- a/benchmark/tree_bench.c
+++ b/benchmark/tree_bench.c
@@ -1,18 +1,5 @@
-/*
-  Copyright 2011-2020 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2011-2020 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #include "bench.h"
 #include "warnings.h"
diff --git a/benchmark/warnings.h b/benchmark/warnings.h
index cb3a618..59f479d 100644
--- a/benchmark/warnings.h
+++ b/benchmark/warnings.h
@@ -1,18 +1,5 @@
-/*
-  Copyright 2020 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2020 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #ifndef WARNINGS_H
 #define WARNINGS_H
diff --git a/include/zix/allocator.h b/include/zix/allocator.h
index 73e2207..55bbe9b 100644
--- a/include/zix/allocator.h
+++ b/include/zix/allocator.h
@@ -1,18 +1,5 @@
-/*
-  Copyright 2021 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2021 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #ifndef ZIX_ALLOCATOR_H
 #define ZIX_ALLOCATOR_H
diff --git a/include/zix/attributes.h b/include/zix/attributes.h
index 255b315..3499a7d 100644
--- a/include/zix/attributes.h
+++ b/include/zix/attributes.h
@@ -1,18 +1,5 @@
-/*
-  Copyright 2021 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2021 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #ifndef ZIX_ATTRIBUTES_H
 #define ZIX_ATTRIBUTES_H
diff --git a/include/zix/bitset.h b/include/zix/bitset.h
index b6e4bac..56658da 100644
--- a/include/zix/bitset.h
+++ b/include/zix/bitset.h
@@ -1,18 +1,5 @@
-/*
-  Copyright 2014-2020 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2014-2020 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #ifndef ZIX_BITSET_H
 #define ZIX_BITSET_H
diff --git a/include/zix/btree.h b/include/zix/btree.h
index 9c67dda..82b017a 100644
--- a/include/zix/btree.h
+++ b/include/zix/btree.h
@@ -1,18 +1,5 @@
-/*
-  Copyright 2011-2020 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2011-2020 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #ifndef ZIX_BTREE_H
 #define ZIX_BTREE_H
diff --git a/include/zix/common.h b/include/zix/common.h
index cfadb65..eaac408 100644
--- a/include/zix/common.h
+++ b/include/zix/common.h
@@ -1,18 +1,5 @@
-/*
-  Copyright 2016-2020 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2016-2020 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #ifndef ZIX_COMMON_H
 #define ZIX_COMMON_H
diff --git a/include/zix/digest.h b/include/zix/digest.h
index 6462717..2becad2 100644
--- a/include/zix/digest.h
+++ b/include/zix/digest.h
@@ -1,18 +1,5 @@
-/*
-  Copyright 2012-2021 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2012-2021 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #ifndef ZIX_DIGEST_H
 #define ZIX_DIGEST_H
diff --git a/include/zix/hash.h b/include/zix/hash.h
index cc56d0e..7ec9f92 100644
--- a/include/zix/hash.h
+++ b/include/zix/hash.h
@@ -1,18 +1,5 @@
-/*
-  Copyright 2011-2021 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2011-2021 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #ifndef ZIX_HASH_H
 #define ZIX_HASH_H
diff --git a/include/zix/ring.h b/include/zix/ring.h
index af98ecf..a060697 100644
--- a/include/zix/ring.h
+++ b/include/zix/ring.h
@@ -1,18 +1,5 @@
-/*
-  Copyright 2011-2020 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2011-2020 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #ifndef ZIX_RING_H
 #define ZIX_RING_H
diff --git a/include/zix/sem.h b/include/zix/sem.h
index 7ff601b..0337f03 100644
--- a/include/zix/sem.h
+++ b/include/zix/sem.h
@@ -1,18 +1,5 @@
-/*
-  Copyright 2012-2020 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2012-2020 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #ifndef ZIX_SEM_H
 #define ZIX_SEM_H
diff --git a/include/zix/thread.h b/include/zix/thread.h
index baf1fde..74bb19b 100644
--- a/include/zix/thread.h
+++ b/include/zix/thread.h
@@ -1,18 +1,5 @@
-/*
-  Copyright 2012-2020 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2012-2020 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #ifndef ZIX_THREAD_H
 #define ZIX_THREAD_H
diff --git a/include/zix/tree.h b/include/zix/tree.h
index c3b9262..aaa0f25 100644
--- a/include/zix/tree.h
+++ b/include/zix/tree.h
@@ -1,18 +1,5 @@
-/*
-  Copyright 2011-2020 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2011-2020 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #ifndef ZIX_TREE_H
 #define ZIX_TREE_H
diff --git a/meson.build b/meson.build
index fb8e2a7..4f47b71 100644
--- a/meson.build
+++ b/meson.build
@@ -1,3 +1,6 @@
+# Copyright 2020-2021 David Robillard <d@drobilla.net>
+# SPDX-License-Identifier: CC0-1.0 OR ISC
+
 project('zix', ['c'],
         version: '0.0.3',
         license: 'ISC',
@@ -240,6 +243,14 @@ tests = [
 
 # Build and run tests
 if get_option('tests')
+  # Check licensing metadata
+  reuse = find_program('reuse', required: false)
+  if reuse.found()
+    test('REUSE', reuse,
+         args: ['--root', meson.current_source_dir(), 'lint'],
+         suite: 'data')
+  endif
+
   thread_dep = dependency('threads')
   dl_dep = cc.find_library('dl', required: false)
 
diff --git a/scripts/benchmark.py b/scripts/benchmark.py
index 5ea1d9f..2249fd1 100755
--- a/scripts/benchmark.py
+++ b/scripts/benchmark.py
@@ -1,5 +1,8 @@
 #!/usr/bin/env python
 
+# Copyright 2011-2021 David Robillard <d@drobilla.net>
+# SPDX-License-Identifier: ISC
+
 """
 Benchmark Zix data structures.
 """
diff --git a/scripts/plot.py b/scripts/plot.py
index 29fffa9..a59e26d 100755
--- a/scripts/plot.py
+++ b/scripts/plot.py
@@ -1,5 +1,8 @@
 #!/usr/bin/env python
 
+# Copyright 2011-2020 David Robillard <d@drobilla.net>
+# SPDX-License-Identifier: ISC
+
 import math
 import os
 import sys
diff --git a/src/allocator.c b/src/allocator.c
index ccd48ea..e4a9f83 100644
--- a/src/allocator.c
+++ b/src/allocator.c
@@ -1,18 +1,5 @@
-/*
-  Copyright 2011-2021 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2011-2021 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #include "zix/allocator.h"
 
diff --git a/src/bitset.c b/src/bitset.c
index 2779de6..6889925 100644
--- a/src/bitset.c
+++ b/src/bitset.c
@@ -1,18 +1,5 @@
-/*
-  Copyright 2014-2020 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2014-2020 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #include "zix/bitset.h"
 
diff --git a/src/btree.c b/src/btree.c
index b74eb92..cdb50fa 100644
--- a/src/btree.c
+++ b/src/btree.c
@@ -1,18 +1,5 @@
-/*
-  Copyright 2011-2021 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2011-2021 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #include "zix/btree.h"
 
diff --git a/src/digest.c b/src/digest.c
index 32cae63..6483eb0 100644
--- a/src/digest.c
+++ b/src/digest.c
@@ -1,18 +1,5 @@
-/*
-  Copyright 2012-2021 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2012-2021 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #include "zix/digest.h"
 
diff --git a/src/hash.c b/src/hash.c
index 00ab2c0..8ee986c 100644
--- a/src/hash.c
+++ b/src/hash.c
@@ -1,18 +1,5 @@
-/*
-  Copyright 2011-2021 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2011-2021 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #include "zix/hash.h"
 
diff --git a/src/ring.c b/src/ring.c
index ed1f32e..14a55e3 100644
--- a/src/ring.c
+++ b/src/ring.c
@@ -1,18 +1,5 @@
-/*
-  Copyright 2011-2020 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2011-2020 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #include "zix/ring.h"
 
diff --git a/src/tree.c b/src/tree.c
index 94cbab5..ccf60a6 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -1,18 +1,5 @@
-/*
-  Copyright 2011-2020 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2011-2020 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #include "zix/tree.h"
 
diff --git a/src/tree_debug.h b/src/tree_debug.h
index eba6b34..7867658 100644
--- a/src/tree_debug.h
+++ b/src/tree_debug.h
@@ -1,18 +1,5 @@
-/*
-  Copyright 2011-2020 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2011-2020 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #ifndef ZIX_TREE_DEBUG_H
 #define ZIX_TREE_DEBUG_H
diff --git a/test/allocator_test.c b/test/allocator_test.c
index 432b836..6850bdc 100644
--- a/test/allocator_test.c
+++ b/test/allocator_test.c
@@ -1,18 +1,5 @@
-/*
-  Copyright 2014-2021 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2014-2021 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #undef NDEBUG
 
diff --git a/test/bitset_test.c b/test/bitset_test.c
index c0833e7..261b1c3 100644
--- a/test/bitset_test.c
+++ b/test/bitset_test.c
@@ -1,18 +1,5 @@
-/*
-  Copyright 2014-2020 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2014-2020 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #include "zix/attributes.h"
 #include "zix/bitset.h"
diff --git a/test/btree_test.c b/test/btree_test.c
index 00a5790..b526551 100644
--- a/test/btree_test.c
+++ b/test/btree_test.c
@@ -1,18 +1,5 @@
-/*
-  Copyright 2011-2020 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2011-2020 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #undef NDEBUG
 
diff --git a/test/digest_test.c b/test/digest_test.c
index 75dc8ff..59d28b3 100644
--- a/test/digest_test.c
+++ b/test/digest_test.c
@@ -1,18 +1,5 @@
-/*
-  Copyright 2020-2021 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2020-2021 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #undef NDEBUG
 
diff --git a/test/failing_allocator.c b/test/failing_allocator.c
index bb569de..d00f2f1 100644
--- a/test/failing_allocator.c
+++ b/test/failing_allocator.c
@@ -1,18 +1,5 @@
-/*
-  Copyright 2021 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2021 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #include "failing_allocator.h"
 
diff --git a/test/failing_allocator.h b/test/failing_allocator.h
index b9daf75..89bee88 100644
--- a/test/failing_allocator.h
+++ b/test/failing_allocator.h
@@ -1,18 +1,5 @@
-/*
-  Copyright 2021 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2021 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #ifndef ZIX_FAILING_ALLOCATOR_H
 #define ZIX_FAILING_ALLOCATOR_H
diff --git a/test/hash_test.c b/test/hash_test.c
index 62e2d18..7f9952d 100644
--- a/test/hash_test.c
+++ b/test/hash_test.c
@@ -1,18 +1,5 @@
-/*
-  Copyright 2011-2020 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2011-2020 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #undef NDEBUG
 
diff --git a/test/ring_test.c b/test/ring_test.c
index ea6a752..447eba6 100644
--- a/test/ring_test.c
+++ b/test/ring_test.c
@@ -1,18 +1,5 @@
-/*
-  Copyright 2011-2021 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2011-2021 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #undef NDEBUG
 
diff --git a/test/sem_test.c b/test/sem_test.c
index 4cca484..33859f1 100644
--- a/test/sem_test.c
+++ b/test/sem_test.c
@@ -1,18 +1,5 @@
-/*
-  Copyright 2012-2021 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2012-2021 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #undef NDEBUG
 
diff --git a/test/strerror_test.c b/test/strerror_test.c
index 1173c3a..a368c68 100644
--- a/test/strerror_test.c
+++ b/test/strerror_test.c
@@ -1,18 +1,5 @@
-/*
-  Copyright 2021 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2021 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #undef NDEBUG
 
diff --git a/test/test_data.h b/test/test_data.h
index 405b716..c5eaace 100644
--- a/test/test_data.h
+++ b/test/test_data.h
@@ -1,18 +1,5 @@
-/*
-  Copyright 2011-2021 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2011-2021 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #ifndef ZIX_TEST_DATA_H
 #define ZIX_TEST_DATA_H
diff --git a/test/test_malloc.c b/test/test_malloc.c
index 4629df0..4274af2 100644
--- a/test/test_malloc.c
+++ b/test/test_malloc.c
@@ -1,18 +1,5 @@
-/*
-  Copyright 2014-2020 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2014-2020 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #ifndef __APPLE__
 #  define _GNU_SOURCE
diff --git a/test/test_malloc.h b/test/test_malloc.h
index fdd2098..7ebf944 100644
--- a/test/test_malloc.h
+++ b/test/test_malloc.h
@@ -1,18 +1,5 @@
-/*
-  Copyright 2014-2020 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2014-2020 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #include "zix/attributes.h"
 
diff --git a/test/tree_test.c b/test/tree_test.c
index 7d2b6af..7125b73 100644
--- a/test/tree_test.c
+++ b/test/tree_test.c
@@ -1,18 +1,5 @@
-/*
-  Copyright 2011-2020 David Robillard <d@drobilla.net>
-
-  Permission to use, copy, modify, and/or distribute this software for any
-  purpose with or without fee is hereby granted, provided that the above
-  copyright notice and this permission notice appear in all copies.
-
-  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
+// Copyright 2011-2020 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
 
 #include "test_data.h"