1 files changed, 124 insertions, 0 deletions
diff --git a/lib/base/fifo.cpp b/lib/base/fifo.cpp
new file mode 100644
index 0000000..8653f51
--- /dev/null
+++ b/lib/base/fifo.cpp
@@ -0,0 +1,124 @@
+/* Icinga 2 | (c) 2012 Icinga GmbH | GPLv2+ */
+
+#include "base/fifo.hpp"
+
+using namespace icinga;
+
+/**
+ * Destructor for the FIFO class.
+ */
+FIFO::~FIFO()
+{
+	free(m_Buffer);
+}
+
+/**
+ * Resizes the FIFO's buffer so that it is at least newSize bytes long.
+ *
+ * @param newSize The minimum new size of the FIFO buffer.
+ */
+void FIFO::ResizeBuffer(size_t newSize, bool decrease)
+{
+	if (m_AllocSize >= newSize && !decrease)
+		return;
+
+	newSize = (newSize / FIFO::BlockSize + 1) * FIFO::BlockSize;
+
+	if (newSize == m_AllocSize)
+		return;
+
+	auto *newBuffer = static_cast<char *>(realloc(m_Buffer, newSize));
+
+	if (!newBuffer)
+		BOOST_THROW_EXCEPTION(std::bad_alloc());
+
+	m_Buffer = newBuffer;
+
+	m_AllocSize = newSize;
+}
+
+/**
+ * Optimizes memory usage of the FIFO buffer by reallocating
+ * and moving the buffer.
+ */
+void FIFO::Optimize()
+{
+	if (m_Offset > m_DataSize / 10 && m_Offset - m_DataSize > 1024) {
+		std::memmove(m_Buffer, m_Buffer + m_Offset, m_DataSize);
+		m_Offset = 0;
+
+		if (m_DataSize > 0)
+			ResizeBuffer(m_DataSize, true);
+
+		return;
+	}
+}
+
+size_t FIFO::Peek(void *buffer, size_t count, bool allow_partial)
+{
+	ASSERT(allow_partial);
+
+	if (count > m_DataSize)
+		count = m_DataSize;
+
+	if (buffer)
+		std::memcpy(buffer, m_Buffer + m_Offset, count);
+
+	return count;
+}
+
+/**
+ * Implements IOQueue::Read.
+ */
+size_t FIFO::Read(void *buffer, size_t count, bool allow_partial)
+{
+	ASSERT(allow_partial);
+
+	if (count > m_DataSize)
+		count = m_DataSize;
+
+	if (buffer)
+		std::memcpy(buffer, m_Buffer + m_Offset, count);
+
+	m_DataSize -= count;
+	m_Offset += count;
+
+	Optimize();
+
+	return count;
+}
+
+/**
+ * Implements IOQueue::Write.
+ */
+void FIFO::Write(const void *buffer, size_t count)
+{
+	ResizeBuffer(m_Offset + m_DataSize + count, false);
+	std::memcpy(m_Buffer + m_Offset + m_DataSize, buffer, count);
+	m_DataSize += count;
+
+	SignalDataAvailable();
+}
+
+void FIFO::Close()
+{ }
+
+bool FIFO::IsEof() const
+{
+	return false;
+}
+
+size_t FIFO::GetAvailableBytes() const
+{
+	return m_DataSize;
+}
+
+bool FIFO::SupportsWaiting() const
+{
+	return true;
+}
+
+bool FIFO::IsDataAvailable() const
+{
+	return m_DataSize > 0;
+}