1 files changed, 91 insertions, 0 deletions
diff --git a/lib/base/ringbuffer.cpp b/lib/base/ringbuffer.cpp
new file mode 100644
index 0000000..52e2ae5
--- /dev/null
+++ b/lib/base/ringbuffer.cpp
@@ -0,0 +1,91 @@
+/* Icinga 2 | (c) 2012 Icinga GmbH | GPLv2+ */
+
+#include "base/ringbuffer.hpp"
+#include "base/objectlock.hpp"
+#include "base/utility.hpp"
+#include <algorithm>
+
+using namespace icinga;
+
+RingBuffer::RingBuffer(RingBuffer::SizeType slots)
+	: m_Slots(slots, 0), m_TimeValue(0), m_InsertedValues(0)
+{ }
+
+RingBuffer::SizeType RingBuffer::GetLength() const
+{
+	std::unique_lock<std::mutex> lock(m_Mutex);
+	return m_Slots.size();
+}
+
+void RingBuffer::InsertValue(RingBuffer::SizeType tv, int num)
+{
+	std::unique_lock<std::mutex> lock(m_Mutex);
+
+	InsertValueUnlocked(tv, num);
+}
+
+void RingBuffer::InsertValueUnlocked(RingBuffer::SizeType tv, int num)
+{
+	RingBuffer::SizeType offsetTarget = tv % m_Slots.size();
+
+	if (m_TimeValue == 0)
+		m_InsertedValues = 1;
+
+	if (tv > m_TimeValue) {
+		RingBuffer::SizeType offset = m_TimeValue % m_Slots.size();
+
+		/* walk towards the target offset, resetting slots to 0 */
+		while (offset != offsetTarget) {
+			offset++;
+
+			if (offset >= m_Slots.size())
+				offset = 0;
+
+			m_Slots[offset] = 0;
+
+			if (m_TimeValue != 0 && m_InsertedValues < m_Slots.size())
+				m_InsertedValues++;
+		}
+
+		m_TimeValue = tv;
+	}
+
+	m_Slots[offsetTarget] += num;
+}
+
+int RingBuffer::UpdateAndGetValues(RingBuffer::SizeType tv, RingBuffer::SizeType span)
+{
+	std::unique_lock<std::mutex> lock(m_Mutex);
+
+	return UpdateAndGetValuesUnlocked(tv, span);
+}
+
+int RingBuffer::UpdateAndGetValuesUnlocked(RingBuffer::SizeType tv, RingBuffer::SizeType span)
+{
+	InsertValueUnlocked(tv, 0);
+
+	if (span > m_Slots.size())
+		span = m_Slots.size();
+
+	int off = m_TimeValue % m_Slots.size();
+	int sum = 0;
+	while (span > 0) {
+		sum += m_Slots[off];
+
+		if (off == 0)
+			off = m_Slots.size();
+
+		off--;
+		span--;
+	}
+
+	return sum;
+}
+
+double RingBuffer::CalculateRate(RingBuffer::SizeType tv, RingBuffer::SizeType span)
+{
+	std::unique_lock<std::mutex> lock(m_Mutex);
+
+	int sum = UpdateAndGetValuesUnlocked(tv, span);
+	return sum / static_cast<double>(std::min(span, m_InsertedValues));
+}