/*
Open Asset Import Library (assimp)
----------------------------------------------------------------------

Copyright (c) 2006-2022, assimp team


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  copyright notice, this list of conditions and the
  following disclaimer.

* Redistributions in binary form must reproduce the above
  copyright notice, this list of conditions and the
  following disclaimer in the documentation and/or other
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* Neither the name of the assimp team, nor the names of its
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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----------------------------------------------------------------------
*/

/** @file  StackAllocator.h
 *  @brief A very bare-bone allocator class that is suitable when
 *      allocating many small objects, e.g. during parsing.
 *      Individual objects are not freed, instead only the whole memory
 *      can be deallocated.
 */
#ifndef AI_STACK_ALLOCATOR_H_INC
#define AI_STACK_ALLOCATOR_H_INC


#include <deque>

namespace Assimp
{

/** @brief A very bare-bone allocator class that is suitable when
 *      allocating many small objects, e.g. during parsing.
 *      Individual objects are not freed, instead only the whole memory
 *      can be deallocated.
*/
class StackAllocator {
public:
    // Constructs the allocator
    StackAllocator();
    // Destructs the allocator and frees all memory
    ~StackAllocator();

    // Returns a pointer to byteSize bytes of heap memory that persists
    // for the lifetime of the allocator (or until FreeAll is called).
    void *Allocate(size_t byteSize);

    // Releases all the memory owned by this allocator.
    // Memory provided through function Allocate is not valid anymore after this function has been called.
    void FreeAll();

private:
    constexpr const static size_t g_maxBytesPerBlock = 64 * 1024 * 1024; // The maximum size (in bytes) of a block
    constexpr const static size_t g_startBytesPerBlock = 16 * 1024;  // Size of the first block. Next blocks will double in size until maximum size of g_maxBytesPerBlock
    size_t m_blockAllocationSize = g_startBytesPerBlock; // Block size of the current block
    size_t m_subIndex = g_maxBytesPerBlock; // The current byte offset in the current block
    std::deque<uint8_t *> m_storageBlocks;  // A list of blocks
};


} // namespace Assimp

#endif // include guard