c6590ad07b
resize keeps previous data intact when the buffer grows resize_destructive destroys the previous data when the buffer grows
96 lines
2.6 KiB
C++
96 lines
2.6 KiB
C++
// SPDX-FileCopyrightText: Copyright 2022 yuzu Emulator Project
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// SPDX-License-Identifier: GPL-2.0-or-later
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#pragma once
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#include "common/make_unique_for_overwrite.h"
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namespace Common {
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/**
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* ScratchBuffer class
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* This class creates a default initialized heap allocated buffer for cases such as intermediate
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* buffers being copied into entirely, where value initializing members during allocation or resize
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* is redundant.
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*/
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template <typename T>
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class ScratchBuffer {
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public:
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ScratchBuffer() = default;
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explicit ScratchBuffer(size_t initial_capacity)
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: last_requested_size{initial_capacity}, buffer_capacity{initial_capacity},
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buffer{Common::make_unique_for_overwrite<T[]>(initial_capacity)} {}
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~ScratchBuffer() = default;
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/// This will only grow the buffer's capacity if size is greater than the current capacity.
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/// The previously held data will remain intact.
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void resize(size_t size) {
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if (size > buffer_capacity) {
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auto new_buffer = Common::make_unique_for_overwrite<T[]>(size);
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std::move(buffer.get(), buffer.get() + buffer_capacity, new_buffer.get());
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buffer = std::move(new_buffer);
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buffer_capacity = size;
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}
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last_requested_size = size;
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}
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/// This will only grow the buffer's capacity if size is greater than the current capacity.
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/// The previously held data will be destroyed if a reallocation occurs.
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void resize_destructive(size_t size) {
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if (size > buffer_capacity) {
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buffer_capacity = size;
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buffer = Common::make_unique_for_overwrite<T[]>(buffer_capacity);
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}
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last_requested_size = size;
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}
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[[nodiscard]] T* data() noexcept {
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return buffer.get();
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}
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[[nodiscard]] const T* data() const noexcept {
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return buffer.get();
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}
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[[nodiscard]] T* begin() noexcept {
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return data();
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}
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[[nodiscard]] const T* begin() const noexcept {
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return data();
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}
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[[nodiscard]] T* end() noexcept {
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return data() + last_requested_size;
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}
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[[nodiscard]] const T* end() const noexcept {
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return data() + last_requested_size;
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}
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[[nodiscard]] T& operator[](size_t i) {
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return buffer[i];
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}
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[[nodiscard]] const T& operator[](size_t i) const {
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return buffer[i];
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}
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[[nodiscard]] size_t size() const noexcept {
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return last_requested_size;
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}
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[[nodiscard]] size_t capacity() const noexcept {
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return buffer_capacity;
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}
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private:
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size_t last_requested_size{};
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size_t buffer_capacity{};
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std::unique_ptr<T[]> buffer{};
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};
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} // namespace Common
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