Add stdalgo::iterator_range and switch config tag reading to use it.

This allows us to use range-based for loops which were not possible
with the previous config tag system.

3 files changed, 72 insertions, 1 deletions

diff --git a/include/inspircd.h b/include/inspircd.h
index 0fc86fa6e..7dbd6948e 100644
--- a/include/inspircd.h
+++ b/include/inspircd.h
@@ -61,6 +61,7 @@
 #include "flat_map.h"
 #include "compat.h"
 #include "aligned_storage.h"
+#include "iterator_range.h"
 #include "typedefs.h"
 #include "convto.h"
 #include "stdalgo.h"
diff --git a/include/iterator_range.h b/include/iterator_range.h
new file mode 100644
index 000000000..86aac4e7b
--- /dev/null
+++ b/include/iterator_range.h
@@ -0,0 +1,69 @@
+/*
+ * 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 stdalgo
+{
+	template <typename Iterator>
+	class iterator_range;
+}
+
+template <typename Iterator>
+class stdalgo::iterator_range
+{
+ 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); }
+};
diff --git a/include/typedefs.h b/include/typedefs.h
index a9ea23e30..a779fde3b 100644
--- a/include/typedefs.h
+++ b/include/typedefs.h
@@ -105,8 +105,9 @@ typedef std::multimap<std::string, reference<ConfigTag>, irc::insensitive_swo> C
 
 /** Iterator of ConfigDataHash */
 typedef ConfigDataHash::const_iterator ConfigIter;
+
 /** Iterator pair, used for tag-name ranges */
-typedef std::pair<ConfigIter,ConfigIter> ConfigTagList;
+typedef stdalgo::iterator_range<ConfigIter> ConfigTagList;
 
 /** Files read by the configuration */
 typedef std::map<std::string, file_cache> ConfigFileCache;