CTT - add CacheRowSpan class

Author: Zadamsa

storage/cacheRowSpan.cpp

@@ -0,0 +1,91 @@
+/**
+* \file
+ * \author Damir Zainullin <[email protected]>
+ * \brief CacheRowSpan implementation.
+ */
+/*
+ * Copyright (C) 2023 CESNET
+ *
+ * LICENSE TERMS
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name of the Company nor the names of its contributors
+ *    may be used to endorse or promote products derived from this
+ *    software without specific prior written permission.
+ */
+
+#include "cacheRowSpan.hpp"
+
+#include <algorithm>
+
+#include "fragmentationCache/timevalUtils.hpp"
+
+namespace ipxp {
+
+CacheRowSpan::CacheRowSpan(FlowRecord** begin, size_t count) noexcept
+   : m_begin(begin), m_count(count)
+{
+}
+
+std::optional<size_t> CacheRowSpan::find_by_hash(uint64_t hash) const noexcept
+{
+   auto it = std::find_if(m_begin, m_begin + m_count, [&](const FlowRecord* flow) {
+      return flow->belongs(hash);
+   });
+   if (it == m_begin + m_count) {
+      return std::nullopt;
+   }
+   return it - m_begin;
+}
+
+void CacheRowSpan::advance_flow_to(size_t from, size_t to) noexcept
+{
+   if (from < to) {
+      std::rotate(m_begin + from, m_begin + from + 1, m_begin + to + 1);
+      return;
+   }
+   std::rotate(m_begin + to, m_begin + from, m_begin + from + 1);
+}
+
+void CacheRowSpan::advance_flow(size_t flow_index) noexcept
+{
+   advance_flow_to(flow_index, 0);
+}
+
+std::optional<size_t> CacheRowSpan::find_empty() const noexcept
+{
+   auto it = std::find_if(m_begin, m_begin + m_count, [](const FlowRecord* flow) {
+      return flow->is_empty();
+   });
+   if (it == m_begin + m_count) {
+      return std::nullopt;
+   }
+   return it - m_begin;
+}
+
+#ifdef WITH_CTT
+size_t CacheRowSpan::find_victim(const timeval& now) const noexcept
+{
+   FlowRecord* const* victim = m_begin + m_count - 1;
+   auto it = std::find_if(m_begin, m_begin + m_count, [&](FlowRecord* const& flow) {
+      if (!flow->is_in_ctt) {
+         victim = &flow;
+      }
+      return flow->is_waiting_for_export && now > flow->export_time;
+   });
+   if (it == m_begin + m_count) {
+      return victim - m_begin;
+   }
+   return it - m_begin;
+}
+#endif /* WITH_CTT */
+
+} // ipxp

storage/cacheRowSpan.hpp

@@ -0,0 +1,82 @@
+/**
+* \file
+ * \author Damir Zainullin <[email protected]>
+ * \brief CacheRowSpan declaration.
+ */
+/*
+ * Copyright (C) 2023 CESNET
+ *
+ * LICENSE TERMS
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name of the Company nor the names of its contributors
+ *    may be used to endorse or promote products derived from this
+ *    software without specific prior written permission.
+ */
+
+#pragma once
+
+#include <cstddef>
+#include <optional>
+#include "flowRecord.hpp"
+
+namespace ipxp {
+/**
+ * \brief Class representing a non-owning view of a row span in a cache.
+ */
+class CacheRowSpan {
+public:
+   /**
+    * \brief Construct a new CacheRowSpan object.
+    * \param begin Pointer to the first element in the row.
+    * \param count Number of elements in the row.
+    */
+   CacheRowSpan(FlowRecord** begin, size_t count) noexcept;
+
+   /**
+    * \brief Find a flow record by hash.
+    * \param hash Hash value to search for.
+    * \return Index of the flow record relative to row begin if found, std::nullopt otherwise.
+    */
+   std::optional<size_t> find_by_hash(uint64_t hash) const noexcept;
+   /**
+    * \brief Move a flow record to the beginning of the row.
+    * \param flow_index Index of the flow record to move.
+    */
+   void advance_flow(size_t flow_index) noexcept;
+
+   /**
+    * \brief Move a flow record to a specific position in the row.
+    * \param from Index of the flow record to move.
+    * \param to Index of the position to move the flow record to.
+    */
+   void advance_flow_to(size_t from, size_t to) noexcept;
+
+   /**
+    * \brief Find an empty flow record in the row.
+    * \return Index of the empty flow record if found, std::nullopt otherwise.
+    */
+   std::optional<size_t> find_empty() const noexcept;
+#ifdef WITH_CTT
+   /**
+    * \brief Find a flow record to be evicted.
+    * \param now Current time.
+    * \return Index of flow from ctt which has delayed export timeout expired if found,
+    * last record which is not in ctt, or last record otherwise
+    */
+   size_t find_victim(const timeval& now) const noexcept;
+#endif /* WITH_CTT */
+private:
+   FlowRecord** m_begin;
+   size_t m_count;
+};
+
+} // ipxp