Create the stdalgo namespace for container-related algorithms, add stdalgo::vector::swaperase()

1 files changed, 66 insertions, 0 deletions

diff --git a/include/stdalgo.h b/include/stdalgo.h
new file mode 100644
index 000000000..758845312
--- /dev/null
+++ b/include/stdalgo.h
@@ -0,0 +1,66 @@
+/*
+ * InspIRCd -- Internet Relay Chat Daemon
+ *
+ *   Copyright (C) 2014 Attila Molnar <attilamolnar@hush.com>
+ *
+ * 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
+{
+	namespace vector
+	{
+		/**
+		 * Erase a single element from a vector by overwriting it with a copy of the last element,
+		 * which is then removed. This, in contrast to vector::erase(), does not result in all
+		 * elements after the erased element being moved.
+		 * @param vect Vector to remove the element from
+		 * @param it Iterator to the element to remove
+		 * @return Nothing, but all iterators, references and pointers to the erased element and the
+		 * last element are invalidated
+		 */
+		template <typename T>
+		inline void swaperase(typename std::vector<T>& vect, const typename std::vector<T>::iterator& it)
+		{
+			*it = vect.back();
+			vect.pop_back();
+		}
+
+		/**
+		 * Find and if exists, erase a single element from a vector by overwriting it with a
+		 * copy of the last element, which is then removed. This, in contrast to vector::erase(),
+		 * does not result in all elements after the erased element being moved.
+		 * If the given value occurs multiple times, the one with the lowest index is removed.
+		 * Individual elements are compared to the given value using operator==().
+		 * @param vect Vector to remove the element from
+		 * @param val Value of the element to look for and remove
+		 * @return True if the element was found and removed, false if it wasn't found.
+		 * If true, all iterators, references and pointers pointing to either the first element that
+		 * is equal to val or to the last element are invalidated.
+		 */
+		template <typename T>
+		inline bool swaperase(typename std::vector<T>& vect, const T& val)
+		{
+			const typename std::vector<T>::iterator it = std::find(vect.begin(), vect.end(), val);
+			if (it != vect.end())
+			{
+				swaperase(vect, it);
+				return true;
+			}
+			return false;
+		}
+	}
+}