common: Add ScratchBuffer class

This class creates a default initialized heap allocated buffer for cases where value initializing members during allocation or resize
is redundant.
This commit is contained in:
ameerj 2022-12-18 18:08:20 -05:00
parent 88ba5a7f22
commit cfc34dd41d
2 changed files with 75 additions and 0 deletions

View file

@ -102,6 +102,7 @@ add_library(common STATIC
${CMAKE_CURRENT_BINARY_DIR}/scm_rev.cpp ${CMAKE_CURRENT_BINARY_DIR}/scm_rev.cpp
scm_rev.h scm_rev.h
scope_exit.h scope_exit.h
scratch_buffer.h
settings.cpp settings.cpp
settings.h settings.h
settings_input.cpp settings_input.cpp

View file

@ -0,0 +1,74 @@
// SPDX-FileCopyrightText: Copyright 2022 yuzu Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#pragma once
#include "common/make_unique_for_overwrite.h"
namespace Common {
/**
* ScratchBuffer class
* This class creates a default initialized heap allocated buffer for cases such as intermediate
* buffers being copied into entirely, where value initializing members during allocation or resize
* is redundant.
*/
template <typename T>
class ScratchBuffer {
public:
ScratchBuffer() = default;
explicit ScratchBuffer(size_t initial_capacity)
: last_requested_size{initial_capacity}, capacity{initial_capacity},
buffer{Common::make_unique_for_overwrite<T[]>(initial_capacity)} {}
~ScratchBuffer() = default;
/// This will only grow the buffer's capacity if size is greater than the current capacity.
void resize(size_t size) {
if (size > capacity) {
capacity = size;
buffer = Common::make_unique_for_overwrite<T[]>(capacity);
}
last_requested_size = size;
}
[[nodiscard]] T* data() noexcept {
return buffer.get();
}
[[nodiscard]] const T* data() const noexcept {
return buffer.get();
}
[[nodiscard]] T* begin() noexcept {
return data();
}
[[nodiscard]] const T* begin() const noexcept {
return data();
}
[[nodiscard]] T* end() noexcept {
return data() + last_requested_size;
}
[[nodiscard]] const T* end() const noexcept {
return data() + last_requested_size;
}
[[nodiscard]] T& operator[](size_t i) {
return buffer[i];
}
[[nodiscard]] size_t size() const noexcept {
return last_requested_size;
}
private:
size_t last_requested_size{};
size_t capacity{};
std::unique_ptr<T[]> buffer{};
};
} // namespace Common