mimir/include/region.h

//
//  region.h
//  Kraken Engine / Mimir
//
//  Copyright 2026 Kearwood Gilbert. All rights reserved.
//
//  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.
//
//  THIS SOFTWARE IS PROVIDED BY KEARWOOD GILBERT ''AS IS'' AND ANY EXPRESS OR IMPLIED
//  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
//  FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL KEARWOOD GILBERT OR
//  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
//  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
//  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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//
//  The views and conclusions contained in the software and documentation are those of the
//  authors and should not be interpreted as representing official policies, either expressed
//  or implied, of Kearwood Gilbert.
//

#pragma once

#include <cstddef>

namespace mimir {

// Dynamically growable memory region with a contiguous address range.
// Provides OS and hardware agnostic reservation and committing of memory pages.
class Region
{
public:
  Region();
  ~Region();

  bool init(size_t maxSize = 1ULL << 32);
  bool resize(size_t size);
  size_t getSize() const;
  size_t getMaxSize() const;
  std::byte* getAddress() const;

  // Helper functions for allocators
  bool maybeGrow(size_t minSize);
  void maybeShrink(size_t targetSize);

private:
  std::byte* m_data;
  size_t m_committedSize;
  size_t m_maxSize;
};

} // namespace mimir