Differential D11103 Diff 40659 source/blender/functions/FN_generic_array.hh

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source/blender/functions/FN_generic_array.hh

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				/*
				* This program is free software; you can redistribute it and/or
				* modify it under the terms of the GNU General Public License
				* as published by the Free Software Foundation; either version 2
				* of the License, or (at your option) any later version.
				*
				* This program is distributed in the hope that it will be useful,
				* but WITHOUT ANY WARRANTY; without even the implied warranty of
				* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
				* GNU General Public License for more details.
				*
				* You should have received a copy of the GNU General Public License
				* along with this program; if not, write to the Free Software Foundation,
				* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
				*/

				#pragma once

				/** \file
				* \ingroup fn
				*
				* This is a generic counterpart to `blender::Array`, used when the type is not known at runtime.
				*
				* `GArray` should generally only be used for passing data around in dynamic contexts.
				* It does not support a few things that `blender::Array` supports:
				* - Small object optimization / inline buffer.
				* - Exception safety and various more specific constructors.
				*
				* Note that a generic vector is purposefully not added to Blender, since it would encourage use of
				* the `append` function, which would be inefficient for dynamic types. Dynamic types should
				JacquesLuckeUnsubmitted Done Inline Actions Not sure if this comment really belongs here, seems unrelated to the entire file. JacquesLucke: Not sure if this comment really belongs here, seems unrelated to the entire file.
				* usually be processed in batches.
				*/

				#include "BLI_allocator.hh"

				#include "FN_cpp_type.hh"
				#include "FN_generic_span.hh"

				namespace blender::fn {

				template<
				/**
				* The allocator used by this array. Should rarely be changed, except when you don't want that
				* MEM_* functions are used internally.
				*/
				typename Allocator = GuardedAllocator>
				class GArray {
				protected:
				/** The type of the data in the array, will be null after the array is default constructed,
				* but a value should be assigned before any other interaction with the array. */
				const CPPType *type_;
				void *data_;
				int64_t size_;

				Allocator allocator_;

				public:
				/**
				* The default constructor creates an empty array, the only situation in which the type is
				* allowed to be null. This default constructor exists so `GArray` can be used in containers,
				* but the type should be supplied before doing anything else to the array.
				*/
				GArray(Allocator allocator = {}) noexcept : allocator_(allocator)
				{
				type_ = nullptr;
				data_ = nullptr;
				size_ = 0;
				}

				/**
				* Create and allocate a new array, with elements default constructed
				* (which does not do anything for trivial types).
				*/
				GArray(const CPPType &type, int64_t size, Allocator allocator = {}) : GArray(type, allocator)
				{
				BLI_assert(size >= 0);
				size_ = size;
				data_ = this->allocate(size_);
				type_->default_construct_n(data_, size_);
				}

				/**
				* Create an empty array with just a type.
				*/
				GArray(const CPPType &type, Allocator allocator = {}) : GArray(allocator)
				{
				type_ = &type;
				data_ = nullptr;
				size_ = 0;
				}

				/**
				* Take ownership of a buffer with a provided size. The buffer should be
				* allocated with the same allocator provided to the constructor.
				*/
				GArray(const CPPType &type, void *buffer, int64_t size, Allocator allocator = {})
				: GArray(type, allocator)
				{
				BLI_assert(size >= 0);
				BLI_assert(buffer != nullptr \|\| size == 0);
				BLI_assert(type_->pointer_has_valid_alignment(buffer));

				data_ = buffer;
				size_ = size;
				}

				/**
				* Create an array by copying values from a generic span.
				*/
				GArray(const GSpan span, Allocator allocator = {}) : GArray(span.type(), span.size(), allocator)
				{
				if (span.data() != nullptr) {
				BLI_assert(span.size() != 0);
				type_->copy_construct_n(span.data(), data_, size_);
				}
				}

				/**
				* Create an array by copying values from another generic array.
				*/
				GArray(const GArray &other) : GArray(other.as_span(), other.allocator())
				{
				}

				/**
				* Create an array by taking ownership of another array's data and destructing it.
				*/
				GArray(GArray &&other) : GArray(other.type(), other.data(), other.size(), other.allocator())
				{
				other.data_ = nullptr;
				other.size_ = 0;
				}

				~GArray()
				{
				if (data_ != nullptr) {
				type_->destruct_n(data_, size_);
				this->deallocate(data_);
				}
				}

				GArray &operator=(const GArray &other)
				{
				return copy_assign_container(*this, other);
				}

				GArray &operator=(GArray &&other)
				{
				return move_assign_container(*this, std::move(other));
				}
				JacquesLuckeUnsubmitted Done Inline Actions This expects that there is a `NoExceptConstructor` constructor. JacquesLucke: This expects that there is a `NoExceptConstructor` constructor.

				const CPPType &type() const
				{
				BLI_assert(type_ != nullptr);
				return *type_;
				}

				bool is_empty() const
				{
				return size_ == 0;
				}

				/**
				* Return the number of elements in the array (not the size in bytes).
				*/
				int64_t size() const
				{
				return size_;
				}

				/**
				* Get a pointer to the beginning of the array.
				*/
				const void *data() const
				{
				return data_;
				}
				void *data()
				{
				return data_;
				}

				const void *operator[](int64_t index) const
				{
				BLI_assert(index < size_);
				return POINTER_OFFSET(data_, type_->size() * index);
				}

				void *operator[](int64_t index)
				{
				BLI_assert(index < size_);
				return POINTER_OFFSET(data_, type_->size() * index);
				}

				operator GSpan() const
				{
				BLI_assert(type_ != nullptr);
				return GSpan(*type_, data_, size_);
				}

				operator GMutableSpan()
				{
				BLI_assert(type_ != nullptr);
				return GMutableSpan(*type_, data_, size_);
				}

				GSpan as_span() const
				{
				return *this;
				}

				GMutableSpan as_mutable_span()
				{
				return *this;
				}

				/**
				* Access the allocator used by this array.
				*/
				Allocator &allocator()
				{
				return allocator_;
				}
				const Allocator &allocator() const
				{
				return allocator_;
				}

				/**
				* Destruct values and create a new array of the given size. The values in the new array are
				* default constructed.
				*/
				void reinitialize(const int64_t new_size)
				{
				BLI_assert(new_size >= 0);
				int64_t old_size = size_;

				type_->destruct_n(data_, size_);
				size_ = 0;

				if (new_size <= old_size) {
				type_->default_construct_n(data_, new_size);
				}
				else {
				void *new_data = this->allocate(new_size);
				try {
				type_->default_construct_n(new_data, new_size);
				}
				catch (...) {
				this->deallocate(new_data);
				throw;
				}
				this->deallocate(data_);
				data_ = new_data;
				}

				size_ = new_size;
				}

				private:
				void *allocate(int64_t size)
				{
				const int64_t item_size = type_->size();
				const int64_t alignment = type_->alignment();
				return allocator_.allocate(static_cast<size_t>(size) * item_size, alignment, AT);
				}

				void deallocate(void *ptr)
				{
				allocator_.deallocate(ptr);
				}
				};

				} // namespace blender::fn
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