linearIndexManager.hpp

/*
 * CoDiPack, a Code Differentiation Package
 *
 * Copyright (C) 2015-2026 Chair for Scientific Computing (SciComp), University of Kaiserslautern-Landau
 * Homepage: http://scicomp.rptu.de
 * Contact:  Prof. Nicolas R. Gauger (codi@scicomp.uni-kl.de)
 *
 * Lead developers: Max Sagebaum, Johannes Blühdorn (SciComp, University of Kaiserslautern-Landau)
 *
 * This file is part of CoDiPack (http://scicomp.rptu.de/software/codi).
 *
 * CoDiPack 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, either version 3 of the
 * License, or (at your option) any later version.
 *
 * CoDiPack 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 CoDiPack.
 * If not, see <http://www.gnu.org/licenses/>.
 *
 * For other licensing options please contact us.
 *
 * Authors:
 *  - SciComp, University of Kaiserslautern-Landau:
 *    - Max Sagebaum
 *    - Johannes Blühdorn
 *    - Former members:
 *      - Tim Albring
 */
#pragma once
 
#include <vector>
 
#include "../../config.h"
#include "../../misc/eventSystem.hpp"
#include "../../misc/macros.hpp"
#include "../data/dataInterface.hpp"
#include "indexManagerInterface.hpp"

namespace codi {

  template<typename T_Index>
  struct LinearIndexManager : public IndexManagerInterface<T_Index>, public DataInterface<> {
    public:
 
      using Index = CODI_DD(T_Index, int);        
      using ActiveTypeIndexData = Index;          
      using Base = IndexManagerInterface<Index>;  
 
      /*******************************************************************************/
 
      static bool constexpr CopyNeedsStatement = false;  
      static bool constexpr IsLinear = true;             
      static bool constexpr NeedsStaticStorage = false;  

      /*******************************************************************************/
 
      using Position = Index;            
      using NestedData = void;           
      using InternalPosHandle = size_t;  

 
    private:
 
      Index reservedIndices;  
      Index count;            
    public:

      LinearIndexManager(Index reservedIndices) : reservedIndices(reservedIndices), count(reservedIndices) {}
 
      /*******************************************************************************/

      void addToTapeValues(TapeValues& values) const {
        TapeValues::LocalReductionOperation constexpr operation =
            NeedsStaticStorage ? TapeValues::LocalReductionOperation::Max : TapeValues::LocalReductionOperation::Sum;
 
        values.addLongEntry("Max. live indices", getLargestCreatedIndex(), operation);
      }

      template<typename Tape>
      CODI_INLINE void freeIndex(Index& index) const {
        if (Config::IndexEvents) {
          if (Base::InactiveIndex != index && Base::InvalidIndex != index) {
            EventSystem<Tape>::notifyIndexFreeListeners(index);
          }
        }
        index = Base::InactiveIndex;
      }

      template<typename Tape>
      CODI_INLINE bool assignIndex(Index& index) {
        if (CODI_ENABLE_CHECK(Config::OverflowCheck, count > count + 1)) {
          CODI_EXCEPTION("Overflow in linear index handler. Use a larger index type or a reuse index manager.");
        }
        count += 1;
        if (Config::IndexEvents) {
          if (Base::InactiveIndex != index && Base::InvalidIndex != index) {
            EventSystem<Tape>::notifyIndexFreeListeners(index);
          }
          EventSystem<Tape>::notifyIndexAssignListeners(count);
        }
        index = count;
        return true;
      }

      template<typename Tape>
      CODI_INLINE bool assignUnusedIndex(Index& index) {
        return assignIndex<Tape>(index);
      }

      template<typename Tape>
      CODI_INLINE void copyIndex(Index& lhs, Index const& rhs) {
        if (Config::IndexEvents) {
          if (Base::InactiveIndex != lhs && Base::InvalidIndex != lhs) {
            EventSystem<Tape>::notifyIndexFreeListeners(lhs);
          }
          EventSystem<Tape>::notifyIndexCopyListeners(rhs);
        }
        lhs = rhs;
      }

      CODI_INLINE Index getLargestCreatedIndex() const {
        return count;
      }

      CODI_INLINE void initIndex(Index& index) {
        index = Index();
      }

      CODI_INLINE void updateLargestCreatedIndex(Index const& index) {
        count = index;
      }

      CODI_INLINE Index const& getIndex(ActiveTypeIndexData const& data) {
        return data;
      }

      CODI_INLINE Index& getIndex(ActiveTypeIndexData& data) {
        return data;
      }

      void validateRhsIndex(ActiveTypeIndexData const& data) const {
        codiAssert(data <= count);
      }

      /*******************************************************************************/

      template<typename TargetPosition>
      CODI_INLINE TargetPosition extractPosition(Position const& pos) const {
        return pos;  // This is a terminator, no further recursion.
      }

      CODI_INLINE size_t getDataSize() const {
        return 0;
      }

      CODI_INLINE Position getPosition() const {
        return count;
      }

      CODI_INLINE size_t getPushedDataCount(InternalPosHandle const& startPos) {
        return count - startPos;
      }

      CODI_INLINE Position getZeroPosition() const {
        return reservedIndices;
      }

      CODI_INLINE void pushData() {}

      CODI_INLINE InternalPosHandle reserveItems(size_t const& items) {
        CODI_UNUSED(items);
 
        return count;
      }

      void resize(size_t const& totalSize) {
        CODI_UNUSED(totalSize);
      }

      CODI_INLINE void resetTo(Position const& pos) {
        codiAssert(pos >= reservedIndices);
 
        count = pos;
      }

      CODI_INLINE void reset() {
        count = reservedIndices;
      }

      CODI_INLINE void resetHard() {
        count = reservedIndices;
      }

      void erase(Position const& start, Position const& end, bool recursive = true) {
        CODI_UNUSED(start, end, recursive);
      }

      void setNested(NestedData* v) {
        CODI_UNUSED(v);
      }

      void swap(LinearIndexManager<Index>& other) {
        std::swap(reservedIndices, other.reservedIndices);
        std::swap(count, other.count);
      }

      template<int selectedDepth = -1, typename FunctionObject, typename... Args>
      CODI_INLINE void evaluateForward(Position const& start, Position const& end, FunctionObject function,
                                       Args&&... args) {
        function(std::forward<Args>(args)..., start, end);
      }

      template<int selectedDepth = -1, typename FunctionObject, typename... Args>
      CODI_INLINE void evaluateReverse(Position const& start, Position const& end, FunctionObject function,
                                       Args&&... args) {
        function(std::forward<Args>(args)..., start, end);
      }

      template<typename FunctionObject, typename... Args>
      CODI_INLINE void forEachChunk(FunctionObject& function, bool recursive, Args&&... args) {
        CODI_UNUSED(function, recursive, args...);
        // Do nothing.
      }

      template<typename FunctionObject, typename... Args>
      CODI_INLINE void forEachForward(Position const& start, Position const& end, FunctionObject function,
                                      Args&&... args) {
        CODI_UNUSED(start, end, function, args...);
      }

      template<typename FunctionObject, typename... Args>
      CODI_INLINE void forEachReverse(Position const& start, Position const& end, FunctionObject function,
                                      Args&&... args) {
        CODI_UNUSED(start, end, function, args...);
      }
  };
}