1 files changed, 114 insertions, 0 deletions
diff --git a/include/2geom/utils.h b/include/2geom/utils.h
new file mode 100644
index 0000000..87f49bb
--- /dev/null
+++ b/include/2geom/utils.h
@@ -0,0 +1,114 @@
+/**
+ * \file
+ * \brief  Various utility functions.
+ *//*
+ * Copyright 2007 Johan Engelen <goejendaagh@zonnet.nl>
+ * Copyright 2006 Michael G. Sloan <mgsloan@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it either under the terms of the GNU Lesser General Public
+ * License version 2.1 as published by the Free Software Foundation
+ * (the "LGPL") or, at your option, under the terms of the Mozilla
+ * Public License Version 1.1 (the "MPL"). If you do not alter this
+ * notice, a recipient may use your version of this file under either
+ * the MPL or the LGPL.
+ *
+ * You should have received a copy of the LGPL along with this library
+ * in the file COPYING-LGPL-2.1; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * You should have received a copy of the MPL along with this library
+ * in the file COPYING-MPL-1.1
+ *
+ * The contents of this file are subject to the Mozilla Public License
+ * Version 1.1 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
+ * OF ANY KIND, either express or implied. See the LGPL or the MPL for
+ * the specific language governing rights and limitations.
+ *
+ */
+
+#ifndef LIB2GEOM_SEEN_UTILS_H
+#define LIB2GEOM_SEEN_UTILS_H
+
+#include <cstddef>
+#include <vector>
+#include <boost/operators.hpp>
+
+namespace Geom {
+
+// Throw these errors instead of aserting so code can handle them if needed.
+using ErrorCode = int;
+enum Errors : ErrorCode {
+    GEOM_ERR_INTERSECGRAPH,
+};
+
+void binomial_coefficients(std::vector<size_t>& bc, std::size_t n);
+
+struct EmptyClass {};
+
+/**
+ * @brief Noncommutative multiplication helper.
+ * Generates operator*(T, U) from operator*=(T, U). Does not generate operator*(U, T)
+ * like boost::multipliable does. This makes it suitable for noncommutative cases,
+ * such as transforms.
+ */
+template <class T, class U, class B = EmptyClass>
+struct MultipliableNoncommutative : B
+{
+    friend T operator*(T const &lhs, U const &rhs) {
+        T nrv(lhs); nrv *= rhs; return nrv;
+    }
+};
+
+/** @brief Null output iterator
+ * Use this if you want to discard a result returned through an output iterator. */
+struct NullIterator
+    : public boost::output_iterator_helper<NullIterator>
+{
+    NullIterator() {}
+
+    template <typename T>
+    void operator=(T const &) {}
+};
+
+/** @brief Get the next iterator in the container with wrap-around.
+ * If the iterator would become the end iterator after incrementing,
+ * return the begin iterator instead. */
+template <typename Iter, typename Container>
+Iter cyclic_next(Iter i, Container &c) {
+    ++i;
+    if (i == c.end()) {
+        i = c.begin();
+    }
+    return i;
+}
+
+/** @brief Get the previous iterator in the container with wrap-around.
+ * If the passed iterator is the begin iterator, return the iterator
+ * just before the end iterator instead. */
+template <typename Iter, typename Container>
+Iter cyclic_prior(Iter i, Container &c) {
+    if (i == c.begin()) {
+        i = c.end();
+    }
+    --i;
+    return i;
+}
+
+} // end namespace Geom
+
+#endif // LIB2GEOM_SEEN_UTILS_H
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :