Move iterator_range to the utility directory and renamespace.

1 files changed, 80 insertions, 0 deletions

diff --git a/include/utility/iterator_range.h b/include/utility/iterator_range.h
new file mode 100644
index 000000000..ff8d8d10e
--- /dev/null
+++ b/include/utility/iterator_range.h
@@ -0,0 +1,80 @@
+/*
+ * InspIRCd -- Internet Relay Chat Daemon
+ *
+ *   Copyright (C) 2020 Sadie Powell <sadie@witchery.services>
+ *
+ * This file is part of InspIRCd.  InspIRCd is free software: you can
+ * redistribute it and/or modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation, version 2.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+#pragma once
+
+namespace insp
+{
+	template <typename Iterator>
+	class iterator_range;
+
+	/** Returns a range containing all elements equivalent to \p value.
+	 * @param collection The collection to search within.
+	 * @param value The value to search for.
+	 */
+	template <typename Collection, typename Value>
+	iterator_range<typename Collection::const_iterator> equal_range(const Collection& collection, const Value& value)
+	{
+		return collection.equal_range(value);
+	}
+}
+
+/** Represents a range of iterators. */
+template <typename Iterator>
+class insp::iterator_range final
+{
+ private:
+	/** An iterator which points to the start of the range. */
+	const Iterator begini;
+
+	/* An iterator which points to one past the end of the range. */
+	const Iterator endi;
+
+ public:
+ 	/** Initialises a new iterator range with the specified iterators.
+ 	 * @param begin An iterator which points to the start of the range.
+ 	 * @param end An iterator which points to one past the end of the range.
+ 	 */
+	iterator_range(Iterator begin, Iterator end)
+		: begini(begin)
+		, endi(end)
+	{
+	}
+
+	/** Initialises a new iterator range from a pair of iterators.
+	 * @param range A pair of iterators in the format [first, last).
+	 */
+	iterator_range(std::pair<Iterator, Iterator> range)
+		: begini(range.first)
+		, endi(range.second)
+	{
+	}
+
+	/** Determines whether the iterator range is empty. */
+	bool empty() const { return begini == endi; }
+
+	/** Retrieves an iterator which points to the start of the range. */
+	const Iterator& begin() const { return begini; }
+
+	/** Retrieves an iterator which points to one past the end of the range. */
+	const Iterator& end() const { return endi; }
+
+	/** Retrieves the number of hops within the iterator range. */
+	typename Iterator::difference_type count() const { return std::distance(begini, endi); }
+};