MultiBuffer.h

// -*- tab-width: 2; indent-tabs-mode: nil; coding: utf-8-with-signature -*-
//-----------------------------------------------------------------------------
// Copyright 2000-2026 CEA (www.cea.fr) IFPEN (www.ifpenergiesnouvelles.com)
// See the top-level COPYRIGHT file for details.
// SPDX-License-Identifier: Apache-2.0
//-----------------------------------------------------------------------------
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/* MultiBuffer.h                                               (C) 2000-2011 */
/*                                                                           */
/* Template class of an array with a buffer.                                 */
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#ifndef ARCANE_UTILS_MULTIBUFFER_H
#define ARCANE_UTILS_MULTIBUFFER_H
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#include "arcane/utils/ArrayView.h"
 
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namespace Arcane
{
 
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template <class T>
class MultiBufferT
{
 public:
 
  typedef UniqueArray<T> BufferType;
 
 public:
 
  MultiBufferT()
  : m_buffer_size(1000)
  , m_current_buffer_size(0)
  , m_nb_in_buffer(0)
  , m_current_buffer(0)
  {
  }
  MultiBufferT(Integer buf_size)
  : m_buffer_size(buf_size)
  , m_current_buffer_size(0)
  , m_nb_in_buffer(0)
  , m_current_buffer(0)
  {
  }

  MultiBufferT(const MultiBufferT<T>& ref)
  : m_buffer_size(ref.m_buffer_size)
  , m_current_buffer_size(0)
  , m_nb_in_buffer(0)
  , m_current_buffer(0)
  {
  }
  ~MultiBufferT()
  {
    _freeAllocatedBuffers();
  }
 
 public:

  void operator=(const MultiBufferT<T>& ref)
  {
    if (&ref == this)
      return;
    clear();
    m_buffer_size = ref.m_buffer_size;
  }
 
 public:

  T* allocOne()
  {
    if (!m_current_buffer)
      _allocateCurrentBuffer();
    T* v = &(*m_current_buffer)[m_nb_in_buffer];
    ++m_nb_in_buffer;
    if (m_nb_in_buffer == m_current_buffer_size)
      m_current_buffer = 0; // Indicates that the current buffer is full
    return v;
  }

  ArrayView<T> allocMany(Integer n)
  {
    // If the desired number of elements is greater than the size
    // of the buffer, specifically allocate a buffer of the correct size
    if (n > m_current_buffer_size) {
      BufferType* bt = new BufferType(n);
      m_allocated_buffers.add(bt);
      return *bt;
    }
    if (!m_current_buffer)
      _allocateCurrentBuffer();
    // If the current buffer is not large enough to contain the
    // \a n desired elements, allocate another one
    if ((m_nb_in_buffer + n) >= m_current_buffer_size)
      _allocateCurrentBuffer();
    T* v = &(*m_current_buffer)[m_nb_in_buffer];
    m_nb_in_buffer += n;
    if (m_nb_in_buffer == m_current_buffer_size)
      m_current_buffer = 0; // Indicates that the current buffer is full
    return ArrayView<T>(n, v);
  }
  void clear()
  {
    m_nb_in_buffer = 0;
    m_current_buffer = 0;
    m_current_buffer_size = 0;
    _freeAllocatedBuffers();
  }
  Integer nbAllocatedBuffer() { return m_allocated_buffers.size(); }
  Integer bufferSize() const { return m_current_buffer_size; }
 
 protected:
 
  void _freeAllocatedBuffers()
  {
    for (Integer i = 0, s = m_allocated_buffers.size(); i < s; ++i)
      delete m_allocated_buffers[i];
    m_allocated_buffers.clear();
  }
 
 private:
 
  Integer m_buffer_size; 
  Integer m_current_buffer_size; 
  Integer m_nb_in_buffer; 
  BufferType* m_current_buffer; 
  UniqueArray<BufferType*> m_allocated_buffers; 
 private:
 
  void _allocateCurrentBuffer()
  {
    m_current_buffer = new BufferType(m_buffer_size);
    m_current_buffer_size = m_buffer_size;
    m_allocated_buffers.add(m_current_buffer);
    m_nb_in_buffer = 0;
  }
};
 
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} // namespace Arcane
 
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#endif