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/*
* Copyright 2019-2021 Diligent Graphics LLC
* Copyright 2015-2019 Egor Yusov
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* In no event and under no legal theory, whether in tort (including negligence),
* contract, or otherwise, unless required by applicable law (such as deliberate
* and grossly negligent acts) or agreed to in writing, shall any Contributor be
* liable for any damages, including any direct, indirect, special, incidental,
* or consequential damages of any character arising as a result of this License or
* out of the use or inability to use the software (including but not limited to damages
* for loss of goodwill, work stoppage, computer failure or malfunction, or any and
* all other commercial damages or losses), even if such Contributor has been advised
* of the possibility of such damages.
*/
#pragma once
/// \file
/// Defines Diligent::DynamicLinearAllocator class
#include <vector>
#include "../../Primitives/interface/BasicTypes.h"
#include "../../Primitives/interface/MemoryAllocator.h"
#include "../../Platforms/Basic/interface/DebugUtilities.hpp"
#include "CompilerDefinitions.h"
#include "Align.hpp"
namespace Diligent
{
/// Implementation of a linear allocator on fixed memory pages
class DynamicLinearAllocator
{
public:
// clang-format off
DynamicLinearAllocator (const DynamicLinearAllocator&) = delete;
DynamicLinearAllocator (DynamicLinearAllocator&&) = delete;
DynamicLinearAllocator& operator=(const DynamicLinearAllocator&) = delete;
DynamicLinearAllocator& operator=(DynamicLinearAllocator&&) = delete;
// clang-format on
explicit DynamicLinearAllocator(IMemoryAllocator& Allocator, Uint32 BlockSize = 4 << 10) :
m_pAllocator{&Allocator},
m_BlockSize{BlockSize}
{
VERIFY(IsPowerOfTwo(BlockSize), "Block size (", BlockSize, ") is not power of two");
}
~DynamicLinearAllocator()
{
Free();
}
void Free()
{
for (auto& block : m_Blocks)
{
m_pAllocator->Free(block.Data);
}
m_Blocks.clear();
m_pAllocator = nullptr;
}
void Discard()
{
for (auto& block : m_Blocks)
{
block.CurrPtr = block.Data;
}
}
NODISCARD void* Allocate(size_t size, size_t align)
{
if (size == 0)
return nullptr;
for (auto& block : m_Blocks)
{
auto* Ptr = AlignUp(block.CurrPtr, align);
if (Ptr + size <= block.Data + block.Size)
{
block.CurrPtr = Ptr + size;
return Ptr;
}
}
// Create a new block
size_t BlockSize = m_BlockSize;
while (BlockSize < size + align - 1)
BlockSize *= 2;
m_Blocks.emplace_back(m_pAllocator->Allocate(BlockSize, "dynamic linear allocator page", __FILE__, __LINE__), BlockSize);
auto& block = m_Blocks.back();
auto* Ptr = AlignUp(block.Data, align);
VERIFY(Ptr + size <= block.Data + block.Size, "Not enough space in the new block - this is a bug");
block.CurrPtr = Ptr + size;
return Ptr;
}
template <typename T>
NODISCARD T* Allocate(size_t count = 1)
{
return reinterpret_cast<T*>(Allocate(sizeof(T) * count, alignof(T)));
}
template <typename T, typename... Args>
NODISCARD T* Construct(Args&&... args)
{
T* Ptr = Allocate<T>(1);
new (Ptr) T{std::forward<Args>(args)...};
return Ptr;
}
template <typename T, typename... Args>
NODISCARD T* ConstructArray(size_t count, const Args&... args)
{
T* Ptr = Allocate<T>(count);
for (size_t i = 0; i < count; ++i)
{
new (Ptr + i) T{args...};
}
return Ptr;
}
template <typename T>
NODISCARD T* CopyArray(const T* Src, size_t count)
{
T* Dst = Allocate<T>(count);
for (size_t i = 0; i < count; ++i)
{
new (Dst + i) T{Src[i]};
}
return Dst;
}
NODISCARD Char* CopyString(const Char* Str, size_t len = 0)
{
if (Str == nullptr)
return nullptr;
if (len == 0)
len = strlen(Str);
else
VERIFY_EXPR(len <= strlen(Str));
Char* Dst = Allocate<Char>(len + 1);
std::memcpy(Dst, Str, sizeof(Char) * len);
Dst[len] = 0;
return Dst;
}
NODISCARD wchar_t* CopyWString(const char* Str, size_t len = 0)
{
if (Str == nullptr)
return nullptr;
if (len == 0)
len = strlen(Str);
else
VERIFY_EXPR(len <= strlen(Str));
auto* Dst = Allocate<wchar_t>(len + 1);
for (size_t i = 0; i < len; ++i)
{
Dst[i] = static_cast<wchar_t>(Str[i]);
}
Dst[len] = 0;
return Dst;
}
NODISCARD Char* CopyString(const String& Str)
{
return CopyString(Str.c_str(), Str.length());
}
NODISCARD wchar_t* CopyWString(const String& Str)
{
return CopyWString(Str.c_str(), Str.length());
}
private:
struct Block
{
uint8_t* const Data = nullptr;
size_t const Size = 0;
uint8_t* CurrPtr = nullptr;
Block(void* _Data, size_t _Size) :
Data{static_cast<uint8_t*>(_Data)}, Size{_Size}, CurrPtr{Data} {}
};
std::vector<Block> m_Blocks;
const Uint32 m_BlockSize = 4 << 10;
IMemoryAllocator* m_pAllocator = nullptr;
};
} // namespace Diligent
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