StackAllocator.hpp

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/*
 * Original work Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
 * Modified work Copyright (c) 2017 Louis Langholtz https://github.com/louis-langholtz/PlayRho
 *
 * This software is provided 'as-is', without any express or implied
 * warranty.  In no event will the authors be held liable for any damages
 * arising from the use of this software.
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 * 1. The origin of this software must not be misrepresented; you must not
 * claim that you wrote the original software. If you use this software
 * in a product, an acknowledgment in the product documentation would be
 * appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 * misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 */
 
#ifndef PLAYRHO_COMMON_STACKALLOCATOR_HPP
#define PLAYRHO_COMMON_STACKALLOCATOR_HPP
 
#include <PlayRho/Common/Settings.hpp>
 
namespace playrho {
 
class StackAllocator
{
public:
 
    using size_type = std::size_t;
 
    struct Conf
    {
        size_type preallocation_size = 100 * 1024; 
        size_type allocation_records = 32; 
    };
 
    static PLAYRHO_CONSTEXPR inline Conf GetDefaultConf()
    {
        return Conf{};
    }
 
    explicit StackAllocator(Conf config = GetDefaultConf()) noexcept;
 
    ~StackAllocator() noexcept;
 
    StackAllocator(const StackAllocator& copy) = delete;
 
    StackAllocator(StackAllocator&& other) = delete;
 
    StackAllocator& operator= (const StackAllocator& other) = delete;
 
    StackAllocator& operator= (StackAllocator&& other) = delete;
 
    void* Allocate(size_type size) noexcept;
 
    void Free(void* p) noexcept;
 
    template <typename T>
    T* AllocateArray(size_type size) noexcept
    {
        return static_cast<T*>(Allocate(size * sizeof(T)));
    }
 
    void operator()(void *p) noexcept
    {
        Free(p);
    }
 
    auto GetMaxAllocation() const noexcept
    {
        return m_maxAllocation;
    }
 
    auto GetEntryCount() const noexcept
    {
        return m_entryCount;
    }
 
    auto GetIndex() const noexcept
    {
        return m_index;
    }
 
    auto GetAllocation() const noexcept
    {
        return m_allocation;
    }
    
    auto GetPreallocatedSize() const noexcept
    {
        return m_size;
    }
    
    auto GetMaxEntries() const noexcept
    {
        return m_max_entries;
    }
    
private:
 
    struct AllocationRecord
    {
        void* data; 
        size_type size; 
        bool usedMalloc; 
    };
    
    char* const m_data; 
    AllocationRecord* const m_entries; 
    size_type const m_size; 
    size_type const m_max_entries; 
    
    size_type m_index = 0; 
    size_type m_allocation = 0; 
    size_type m_maxAllocation = 0; 
    size_type m_entryCount = 0; 
};
    
} // namespace playrho
 
#endif // PLAYRHO_COMMON_STACKALLOCATOR_HPP