mirror of
https://github.com/cocos/cocos-engine.git
synced 2026-09-07 00:02:53 +08:00
64 lines
2.5 KiB
C++
64 lines
2.5 KiB
C++
/****************************************************************************
|
|
Copyright (c) 2020-2021 Xiamen Yaji Software Co., Ltd.
|
|
|
|
http://www.cocos.com
|
|
|
|
Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
of this software and associated engine source code (the "Software"), a limited,
|
|
worldwide, royalty-free, non-assignable, revocable and non-exclusive license
|
|
to use Cocos Creator solely to develop games on your target platforms. You shall
|
|
not use Cocos Creator software for developing other software or tools that's
|
|
used for developing games. You are not granted to publish, distribute,
|
|
sublicense, and/or sell copies of Cocos Creator.
|
|
|
|
The software or tools in this License Agreement are licensed, not sold.
|
|
Xiamen Yaji Software Co., Ltd. reserves all rights not expressly granted to you.
|
|
|
|
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
|
THE SOFTWARE.
|
|
****************************************************************************/
|
|
|
|
#include "ThreadSafeLinearAllocator.h"
|
|
#include "acl/core/memory_utils.h"
|
|
|
|
namespace cc {
|
|
|
|
ThreadSafeLinearAllocator::ThreadSafeLinearAllocator(uint32_t const size) noexcept
|
|
: _capacity(size) {
|
|
_buffer = malloc(size);
|
|
}
|
|
|
|
ThreadSafeLinearAllocator::~ThreadSafeLinearAllocator() {
|
|
free(_buffer);
|
|
}
|
|
|
|
void *ThreadSafeLinearAllocator::allocate(size_t const size, size_t const alignment) noexcept {
|
|
if (size == 0) {
|
|
return nullptr;
|
|
}
|
|
|
|
void * allocatedMemory = nullptr;
|
|
uint32_t oldUsedSize = 0;
|
|
uint64_t newUsedSize = 0; // using 64-bit integer to correctly detect overflows
|
|
|
|
do {
|
|
oldUsedSize = getUsedSize();
|
|
allocatedMemory = acl::align_to(acl::add_offset_to_ptr<void>(_buffer, oldUsedSize), alignment);
|
|
newUsedSize = reinterpret_cast<uintptr_t>(allocatedMemory) - reinterpret_cast<uintptr_t>(_buffer) + size;
|
|
|
|
if (newUsedSize > _capacity) // overflows
|
|
{
|
|
return nullptr;
|
|
}
|
|
} while (!_usedSize.compare_exchange_weak(oldUsedSize, static_cast<uint32_t>(newUsedSize), std::memory_order_relaxed, std::memory_order_relaxed)); // 不可能存在ABA 不处理
|
|
|
|
return allocatedMemory;
|
|
}
|
|
|
|
} // namespace cc
|