Clarify licenses

- add license headers to everything
- convert a few files from public domain or LGPL2.1+ to GPL2+
- some archaeology to clarify which files are from which library

29 files changed, 115 insertions, 52 deletions

diff --git a/src/util/CMakeLists.txt b/src/util/CMakeLists.txt
index faa452d13..102792e7f 100644
--- a/src/util/CMakeLists.txt
+++ b/src/util/CMakeLists.txt
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
 
 set(util_SRC
 	ege-appear-time-tracker.cpp
diff --git a/src/util/copy.h b/src/util/copy.h
index 1b4232814..606813208 100644
--- a/src/util/copy.h
+++ b/src/util/copy.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Inkscape::Traits::Copy - traits class to determine types to use when copying
  *
@@ -6,7 +7,7 @@
  *
  * Copyright (C) 2004 MenTaLguY
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #ifndef SEEN_INKSCAPE_TRAITS_COPY_H
diff --git a/src/util/ege-appear-time-tracker.cpp b/src/util/ege-appear-time-tracker.cpp
index ec24bbd32..d3c08998e 100644
--- a/src/util/ege-appear-time-tracker.cpp
+++ b/src/util/ege-appear-time-tracker.cpp
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later OR MPL-1.1 OR LGPL-2.1-or-later
 /* ***** BEGIN LICENSE BLOCK *****
  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  *
diff --git a/src/util/ege-appear-time-tracker.h b/src/util/ege-appear-time-tracker.h
index 1d0c90991..4318e62fa 100644
--- a/src/util/ege-appear-time-tracker.h
+++ b/src/util/ege-appear-time-tracker.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later OR MPL-1.1 OR LGPL-2.1-or-later
 #ifndef SEEN_APPEAR_TIME_TRACKER_H
 #define SEEN_APPEAR_TIME_TRACKER_H
 
diff --git a/src/util/ege-tags.cpp b/src/util/ege-tags.cpp
index d86d6025f..c37a9d2fe 100644
--- a/src/util/ege-tags.cpp
+++ b/src/util/ege-tags.cpp
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later OR MPL-1.1 OR LGPL-2.1-or-later
 /* ***** BEGIN LICENSE BLOCK *****
  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  *
diff --git a/src/util/ege-tags.h b/src/util/ege-tags.h
index a481c97e1..dfa584d5c 100644
--- a/src/util/ege-tags.h
+++ b/src/util/ege-tags.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later OR MPL-1.1 OR LGPL-2.1-or-later
 #ifndef SEEN_EGE_TAGS_H
 #define SEEN_EGE_TAGS_H
 
diff --git a/src/util/enums.h b/src/util/enums.h
index 2ff5a0af8..46c4d5e8b 100644
--- a/src/util/enums.h
+++ b/src/util/enums.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Authors:
  *   Nicholas Bishop <nicholasbishop@gmail.com>
@@ -5,7 +6,7 @@
  *
  * Copyright (C) 2007 Authors
  *
- * Released under GNU GPL.  Read the file 'COPYING' for more information.
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 #ifndef INKSCAPE_UTIL_ENUMS_H
 #define INKSCAPE_UTIL_ENUMS_H
diff --git a/src/util/expression-evaluator.cpp b/src/util/expression-evaluator.cpp
index e9356ef35..facf5422b 100644
--- a/src/util/expression-evaluator.cpp
+++ b/src/util/expression-evaluator.cpp
@@ -1,3 +1,7 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+/** @file
+ * TODO: insert short description here
+ */
 /* LIBGIMP - The GIMP Library
  * Copyright (C) 1995-1997 Peter Mattis and Spencer Kimball
  *
diff --git a/src/util/expression-evaluator.h b/src/util/expression-evaluator.h
index 343278c53..a45ad5a73 100644
--- a/src/util/expression-evaluator.h
+++ b/src/util/expression-evaluator.h
@@ -1,3 +1,7 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+/** @file
+ * TODO: insert short description here
+ */
 /* LIBGIMP - The GIMP Library
  * Copyright (C) 1995-1997 Peter Mattis and Spencer Kimball
  *
diff --git a/src/util/find-if-before.h b/src/util/find-if-before.h
index 6a0f63be6..b7b2de620 100644
--- a/src/util/find-if-before.h
+++ b/src/util/find-if-before.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Inkscape::Algorithms::find_if_before - finds the position before
  *                                        the first value that satisifes
@@ -8,7 +9,7 @@
  *
  * Copyright (C) 2005 MenTaLguY
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #ifndef SEEN_INKSCAPE_ALGORITHMS_FIND_IF_BEFORE_H
diff --git a/src/util/find-last-if.h b/src/util/find-last-if.h
index 1ffd63b9c..1402de74e 100644
--- a/src/util/find-last-if.h
+++ b/src/util/find-last-if.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Inkscape::Algorithms::find_last_if
  *
@@ -6,7 +7,7 @@
  *
  * Copyright (C) 2004 MenTaLguY
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #ifndef SEEN_INKSCAPE_ALGORITHMS_FIND_LAST_IF_H
diff --git a/src/util/fixed_point.h b/src/util/fixed_point.h
index f2bf0318d..5bb0dde92 100644
--- a/src/util/fixed_point.h
+++ b/src/util/fixed_point.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Inkscape::Util::FixedPoint - fixed point type
  *
@@ -6,7 +7,7 @@
  *
  * Copyright (C) 2006 Jasper van de Gronde
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #ifndef SEEN_INKSCAPE_UTIL_FIXED_POINT_H
diff --git a/src/util/format.h b/src/util/format.h
index 61e004857..b38f3a64a 100644
--- a/src/util/format.h
+++ b/src/util/format.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Inkscape::Util::format - g_strdup_printf wrapper producing shared strings
  *
@@ -6,7 +7,7 @@
  *
  * Copyright (C) 2006 MenTaLguY
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #ifndef SEEN_INKSCAPE_UTIL_FORMAT_H
diff --git a/src/util/forward-pointer-iterator.h b/src/util/forward-pointer-iterator.h
index eaf5a7a25..9fe3bb852 100644
--- a/src/util/forward-pointer-iterator.h
+++ b/src/util/forward-pointer-iterator.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Inkscape::Util::ForwardPointerIterator - wraps a simple pointer
  *                                          with various strategies
@@ -8,7 +9,7 @@
  *
  * Copyright (C) 2004 MenTaLguY
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #ifndef SEEN_INKSCAPE_UTIL_FORWARD_POINTER_ITERATOR_H
diff --git a/src/util/list-container-test.h b/src/util/list-container-test.h
index 5f0e06e0c..b46ed7b9e 100644
--- a/src/util/list-container-test.h
+++ b/src/util/list-container-test.h
@@ -1,3 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/** @file
+ * TODO: insert short description here
+ *//*
+ * Authors: see git history
+ *
+ * Copyright (C) 2010 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
 #include <cxxtest/TestSuite.h>
 
 #include <stdarg.h>
diff --git a/src/util/list-container.h b/src/util/list-container.h
index d39a40ee7..70023875c 100644
--- a/src/util/list-container.h
+++ b/src/util/list-container.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Inkscape::Util::ListContainer - encapsulates lists as STL containers,
  *                                 providing fast appending
@@ -7,7 +8,7 @@
  *
  * Copyright (C) 2005 MenTaLguY
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #ifndef SEEN_INKSCAPE_UTIL_LIST_CONTAINER_H
diff --git a/src/util/list-copy.h b/src/util/list-copy.h
index 28ce66ad3..51e6af4eb 100644
--- a/src/util/list-copy.h
+++ b/src/util/list-copy.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Inkscape::Traits::ListCopy - helper traits class for copying lists
  *
@@ -6,7 +7,7 @@
  *
  * Copyright (C) 2004 MenTaLguY
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #ifndef SEEN_INKSCAPE_TRAITS_LIST_COPY_H
diff --git a/src/util/list.h b/src/util/list.h
index ffe04d9f3..68f410bf1 100644
--- a/src/util/list.h
+++ b/src/util/list.h
@@ -1,10 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Authors:
  *   MenTaLguY <mental@rydia.net>
  *
  * Copyright (C) 2004 MenTaLguY
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #ifndef SEEN_INKSCAPE_UTIL_LIST_H
diff --git a/src/util/longest-common-suffix.h b/src/util/longest-common-suffix.h
index 04d2b179d..bc72e6f8c 100644
--- a/src/util/longest-common-suffix.h
+++ b/src/util/longest-common-suffix.h
@@ -1,12 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
- * Inkscape::Algorithms::longest_common_suffix 
+ * Inkscape::Algorithms::longest_common_suffix
  *
  * Authors:
  *   MenTaLguY <mental@rydia.net>
  *
  * Copyright (C) 2004 MenTaLguY
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #ifndef SEEN_INKSCAPE_ALGORITHMS_LONGEST_COMMON_SUFFIX_H
diff --git a/src/util/reference.h b/src/util/reference.h
index 5c94bbba5..b4a123b93 100644
--- a/src/util/reference.h
+++ b/src/util/reference.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Inkscape::Traits::Reference - traits class for dealing with reference types
  *
@@ -6,7 +7,7 @@
  *
  * Copyright (C) 2004 MenTaLguY
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #ifndef SEEN_INKSCAPE_TRAITS_REFERENCE_H
diff --git a/src/util/reverse-list.h b/src/util/reverse-list.h
index dacbc2a11..c0164085b 100644
--- a/src/util/reverse-list.h
+++ b/src/util/reverse-list.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Inkscape::Util::reverse_list - generate a reversed list from iterator range
  *
@@ -6,7 +7,7 @@
  *
  * Copyright (C) 2004 MenTaLguY
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #ifndef SEEN_INKSCAPE_UTIL_REVERSE_LIST_H
diff --git a/src/util/share.cpp b/src/util/share.cpp
index a9c648d6c..6c436dcf8 100644
--- a/src/util/share.cpp
+++ b/src/util/share.cpp
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Inkscape::Util::ptr_shared<T> - like T const *, but stronger.
  * Used to hold c-style strings for objects that are managed by the gc.
@@ -7,7 +8,7 @@
  *
  * Copyright (C) 2006 MenTaLguY
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #include "util/share.h"
diff --git a/src/util/share.h b/src/util/share.h
index cc3387325..e8b9fb12b 100644
--- a/src/util/share.h
+++ b/src/util/share.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Inkscape::Util::ptr_shared<T> - like T const *, but stronger.
  * Used to hold c-style strings for objects that are managed by the gc.
@@ -7,7 +8,7 @@
  *
  * Copyright (C) 2006 MenTaLguY
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #ifndef SEEN_INKSCAPE_UTIL_SHARE_H
diff --git a/src/util/signal-blocker.h b/src/util/signal-blocker.h
index 9d1f3153a..8fb62569a 100644
--- a/src/util/signal-blocker.h
+++ b/src/util/signal-blocker.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Base RAII blocker for sgic++ signals.
  *
@@ -6,7 +7,7 @@
  *
  * Copyright (C) 2014 Authors
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #ifndef SEEN_INKSCAPE_UTIL_SIGNAL_BLOCKER_H
diff --git a/src/util/ucompose.hpp b/src/util/ucompose.hpp
index b2b07814b..f1e536c0c 100644
--- a/src/util/ucompose.hpp
+++ b/src/util/ucompose.hpp
@@ -1,3 +1,12 @@
+// SPDX-License-Identifier: LGPL-2.1-or-later
+/** @file
+ * TODO: insert short description here
+ *//*
+ * Authors: see git history
+ *
+ * Copyright (C) 2006 Authors
+ * Released under GNU LGPL v2.1+, read the file 'COPYING' for more information.
+ */
 /* Defines String::ucompose(fmt, arg...) for easy, i18n-friendly
  * composition of strings with Gtkmm >= 1.3.* (see www.gtkmm.org).
  * Uses Glib::ustring instead of std::string which doesn't work with
diff --git a/src/util/units.cpp b/src/util/units.cpp
index 0308623d5..8c0be134d 100644
--- a/src/util/units.cpp
+++ b/src/util/units.cpp
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Inkscape Units
  *
@@ -6,7 +7,7 @@
  *
  * Copyright (C) 2013 Matthew Petroff
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #include <cmath>
diff --git a/src/util/units.h b/src/util/units.h
index 17c54eb4e..2b7f8674c 100644
--- a/src/util/units.h
+++ b/src/util/units.h
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Inkscape Units
  * These classes are used for defining different unit systems.
@@ -7,7 +8,7 @@
  *
  * Copyright (C) 2013 Matthew Petroff
  *
- * Released under GNU GPL, read the file 'COPYING' for more information
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
  */
 
 #ifndef INKSCAPE_UTIL_UNITS_H
diff --git a/src/util/ziptool.cpp b/src/util/ziptool.cpp
index a4ad751a0..82712b87d 100644
--- a/src/util/ziptool.cpp
+++ b/src/util/ziptool.cpp
@@ -1,20 +1,15 @@
-/*
- * This is intended to be a standalone, reduced capability
- * implementation of Gzip and Zip functionality.  Its
- * targeted use case is for archiving and retrieving single files
- * which use these encoding types.  Being memory based and
- * non-optimized, it is not useful in cases where very large
- * archives are needed or where high performance is desired.
- * However, it should hopefully work very well for smaller,
- * one-at-a-time tasks.  What you get in return is the ability
- * to drop these files into your project and remove the dependencies
- * on ZLib and Info-Zip.  Enjoy.
- *
+// SPDX-License-Identifier: LGPL-2.1-or-later
+/** @file
+ * TODO: insert short description here
+ *//*
  * Authors:
- *   Bob Jamison
- *
- * Copyright (C) 2006-2007 Bob Jamison
+ * see git history
+ * Bob Jamison
  *
+ * Copyright (C) 2018 Authors
+ * Released under GNU LGPL v2.1+, read the file 'COPYING' for more information.
+ */
+/*
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Lesser General Public
  *  License as published by the Free Software Foundation; either
@@ -29,6 +24,18 @@
  *  License along with this library; if not, write to the Free Software
  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
+/*
+ * This is intended to be a standalone, reduced capability
+ * implementation of Gzip and Zip functionality.  Its
+ * targeted use case is for archiving and retrieving single files
+ * which use these encoding types.  Being memory based and
+ * non-optimized, it is not useful in cases where very large
+ * archives are needed or where high performance is desired.
+ * However, it should hopefully work very well for smaller,
+ * one-at-a-time tasks.  What you get in return is the ability
+ * to drop these files into your project and remove the dependencies
+ * on ZLib and Info-Zip.  Enjoy.
+ */
 
 
 #include <cstdio>
diff --git a/src/util/ziptool.h b/src/util/ziptool.h
index 8d905f405..26aaac81c 100644
--- a/src/util/ziptool.h
+++ b/src/util/ziptool.h
@@ -1,23 +1,15 @@
-#ifndef SEEN_ZIPTOOL_H
-#define SEEN_ZIPTOOL_H
-/**
- * This is intended to be a standalone, reduced capability
- * implementation of Gzip and Zip functionality.  Its
- * targeted use case is for archiving and retrieving single files
- * which use these encoding types.  Being memory based and
- * non-optimized, it is not useful in cases where very large
- * archives are needed or where high performance is desired.
- * However, it should hopefully work well for smaller,
- * one-at-a-time tasks.  What you get in return is the ability
- * to drop these files into your project and remove the dependencies
- * on ZLib and Info-Zip.  Enjoy.
- */
-/*
+// SPDX-License-Identifier: LGPL-2.1-or-later
+/** @file
+ * TODO: insert short description here
+ *//*
  * Authors:
- *   Bob Jamison
- *
- * Copyright (C) 2006-2007 Bob Jamison
+ * see git history
+ * Bob Jamison
  *
+ * Copyright (C) 2018 Authors
+ * Released under GNU LGPL v2.1+, read the file 'COPYING' for more information.
+ */
+/*
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Lesser General Public
  *  License as published by the Free Software Foundation; either
@@ -32,6 +24,21 @@
  *  License along with this library; if not, write to the Free Software
  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
+#ifndef SEEN_ZIPTOOL_H
+#define SEEN_ZIPTOOL_H
+/**
+ * This is intended to be a standalone, reduced capability
+ * implementation of Gzip and Zip functionality.  Its
+ * targeted use case is for archiving and retrieving single files
+ * which use these encoding types.  Being memory based and
+ * non-optimized, it is not useful in cases where very large
+ * archives are needed or where high performance is desired.
+ * However, it should hopefully work well for smaller,
+ * one-at-a-time tasks.  What you get in return is the ability
+ * to drop these files into your project and remove the dependencies
+ * on ZLib and Info-Zip.  Enjoy.
+ */
+
 
 
 #include <vector>