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// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#include "common/alignment.h"
#include "core/file_sys/fssystem/fssystem_pooled_buffer.h"
namespace FileSys {
namespace {
constexpr size_t HeapBlockSize = BufferPoolAlignment;
static_assert(HeapBlockSize == 4_KiB);
// A heap block is 4KiB. An order is a power of two.
// This gives blocks of the order 32KiB, 512KiB, 4MiB.
constexpr s32 HeapOrderMax = 7;
constexpr s32 HeapOrderMaxForLarge = HeapOrderMax + 3;
constexpr size_t HeapAllocatableSizeMax = HeapBlockSize * (static_cast<size_t>(1) << HeapOrderMax);
constexpr size_t HeapAllocatableSizeMaxForLarge =
HeapBlockSize * (static_cast<size_t>(1) << HeapOrderMaxForLarge);
} // namespace
size_t PooledBuffer::GetAllocatableSizeMaxCore(bool large) {
return large ? HeapAllocatableSizeMaxForLarge : HeapAllocatableSizeMax;
}
void PooledBuffer::AllocateCore(size_t ideal_size, size_t required_size, bool large) {
// Ensure preconditions.
ASSERT(m_buffer == nullptr);
// Check that we can allocate this size.
ASSERT(required_size <= GetAllocatableSizeMaxCore(large));
const size_t target_size =
std::min(std::max(ideal_size, required_size), GetAllocatableSizeMaxCore(large));
// Dummy implementation for allocate.
if (target_size > 0) {
m_buffer =
reinterpret_cast<char*>(::operator new(target_size, std::align_val_t{HeapBlockSize}));
m_size = target_size;
// Ensure postconditions.
ASSERT(m_buffer != nullptr);
}
}
void PooledBuffer::Shrink(size_t ideal_size) {
ASSERT(ideal_size <= GetAllocatableSizeMaxCore(true));
// Shrinking to zero means that we have no buffer.
if (ideal_size == 0) {
::operator delete(m_buffer, std::align_val_t{HeapBlockSize});
m_buffer = nullptr;
m_size = ideal_size;
}
}
} // namespace FileSys
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