133 lines
3.9 KiB
C++
133 lines
3.9 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 <iterator>
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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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using element_type = T;
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using value_type = T;
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using size_type = size_t;
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using difference_type = std::ptrdiff_t;
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using pointer = T*;
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using const_pointer = const T*;
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using reference = T&;
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using const_reference = const T&;
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using iterator = pointer;
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using const_iterator = const_pointer;
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using iterator_category = std::random_access_iterator_tag;
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using iterator_concept = std::contiguous_iterator_tag;
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ScratchBuffer() = default;
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explicit ScratchBuffer(size_type 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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ScratchBuffer(const ScratchBuffer&) = delete;
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ScratchBuffer& operator=(const ScratchBuffer&) = delete;
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ScratchBuffer(ScratchBuffer&& other) noexcept {
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swap(other);
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other.last_requested_size = 0;
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other.buffer_capacity = 0;
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other.buffer.reset();
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}
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ScratchBuffer& operator=(ScratchBuffer&& other) noexcept {
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swap(other);
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other.last_requested_size = 0;
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other.buffer_capacity = 0;
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other.buffer.reset();
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return *this;
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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 remain intact.
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void resize(size_type 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_type 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]] pointer data() noexcept {
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return buffer.get();
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}
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[[nodiscard]] const_pointer data() const noexcept {
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return buffer.get();
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}
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[[nodiscard]] iterator begin() noexcept {
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return data();
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}
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[[nodiscard]] const_iterator begin() const noexcept {
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return data();
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}
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[[nodiscard]] iterator end() noexcept {
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return data() + last_requested_size;
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}
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[[nodiscard]] const_iterator end() const noexcept {
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return data() + last_requested_size;
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}
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[[nodiscard]] reference operator[](size_type i) {
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return buffer[i];
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}
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[[nodiscard]] const_reference operator[](size_type i) const {
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return buffer[i];
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}
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[[nodiscard]] size_type size() const noexcept {
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return last_requested_size;
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}
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[[nodiscard]] size_type capacity() const noexcept {
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return buffer_capacity;
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}
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void swap(ScratchBuffer& other) noexcept {
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std::swap(last_requested_size, other.last_requested_size);
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std::swap(buffer_capacity, other.buffer_capacity);
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std::swap(buffer, other.buffer);
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}
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private:
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size_type last_requested_size{};
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size_type 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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