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This commit is contained in:
2022-09-07 19:14:10 +02:00
parent ff42240ea2
commit bc8f37a21d
4 changed files with 236 additions and 49 deletions

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@@ -0,0 +1,233 @@
/* SPDX-License-Identifier: GPL-2.0-or-later */
#pragma once
/** \file
* \ingroup bli
*
* A `blender::ChunkedList` is a dynamically growing ordered container for values of type T.
* It is *not* guaranteed that all values will be stored in one contiguous array. Instead, multiple
* arrays may be used.
*
* Comparison to `blender::Vector`:
* - `ChunkedList` has better performance when appending many elements, because it does not have to
* move existing values.
* - This also means that `ChunkedList` can be used with types that cannot be moved.
* - A `ChunkedList` can not be indexed efficiently. So while the container is ordered, one can not
* efficiently get the value at a specific index.
* - Iterating over a `ChunkedList` is a little bit slower, because it may have to iterate over
* multiple arrays. That is likely negligible in most cases.
*
* `ChunkedList` should be used instead of `Vector` when the following two statements are true:
* - The elements do not have to be in a contiguous array.
* - The elements do not have to be accessed with an index.
*/
#include "BLI_allocator.hh"
#include "BLI_math_base.hh"
#include "BLI_memory_utils.hh"
#include "BLI_vector.hh"
namespace blender {
namespace detail {
template<typename T> struct alignas(std::max<size_t>(alignof(T), 8)) ChunkListAllocInfo {
Vector<MutableSpan<T>> spans;
};
} // namespace detail
template<typename T,
int64_t InlineBufferCapacity = default_inline_buffer_capacity(sizeof(T)),
typename Allocator = GuardedAllocator>
class ChunkedList {
private:
using AllocInfo = detail::ChunkListAllocInfo<T>;
T *end_;
T *capacity_end_;
AllocInfo *alloc_info_ = nullptr;
BLI_NO_UNIQUE_ADDRESS TypedBuffer<T, InlineBufferCapacity> inline_buffer_;
BLI_NO_UNIQUE_ADDRESS Allocator allocator_;
public:
ChunkedList(Allocator allocator = {}) noexcept : allocator_(allocator)
{
end_ = inline_buffer_;
capacity_end_ = end_ + InlineBufferCapacity;
}
ChunkedList(NoExceptConstructor, Allocator allocator = {}) noexcept : ChunkedList(allocator)
{
}
ChunkedList(const ChunkedList &other)
{
this->extend(other);
}
template<int64_t OtherInlineBufferCapacity>
ChunkedList(const ChunkedList<T, OtherInlineBufferCapacity, Allocator> &other)
: ChunkedList(other.allocator())
{
this->extend(other);
}
const Allocator &allocator() const
{
return allocator_;
}
template<typename Fn> void foreach_span(Fn &&fn) const
{
const T *inline_begin = inline_buffer_;
if (alloc_info_ == nullptr) {
if (end_ > inline_begin) {
fn(Span<T>(inline_begin, end_ - inline_begin));
}
}
else {
if (InlineBufferCapacity > 0) {
fn(Span<T>(inline_begin, InlineBufferCapacity));
}
for (const Span<T> span : alloc_info_->spans) {
fn(span);
}
}
}
template<typename Fn> void foreach_span(Fn &&fn)
{
const_cast<const ChunkedList *>(this)->foreach_span(
[&](const Span<T> span) { fn(MutableSpan(const_cast<T *>(span.data()), span.size())); });
}
std::optional<Span<T>> get_span(const int64_t index) const
{
/* TODO: Define the indices of individual spans. */
return {};
}
void append(const T &value)
{
this->append_as(value);
}
void append(T &&value)
{
this->append_as(std::move(value));
}
template<typename... Args> void append_as(Args &&...args)
{
this->ensure_space_for_one();
BLI_assert(end_ < capacity_end_);
new (end_) T(std::forward<Args>(args)...);
end_++;
}
template<int64_t OtherInlineBufferCapacity>
void extend(const ChunkedList<T, OtherInlineBufferCapacity, Allocator> &list)
{
list.foreach_span([&](const Span<T> span) { this->extend(span); });
}
void extend(const Span<T> values)
{
const T *src_data = values.data();
const int64_t remaining_capacity = capacity_end_ - end_;
const int64_t copy_to_current_chunk = std::min(values.size(), remaining_capacity);
const int64_t copy_to_next_chunk = values.size() - copy_to_current_chunk;
uninitialized_copy_n(src_data, copy_to_current_chunk, end_);
end_ += copy_to_current_chunk;
if (copy_to_next_chunk == 0) {
return;
}
this->add_chunk(copy_to_next_chunk);
try {
uninitialized_copy_n(src_data + copy_to_current_chunk, copy_to_next_chunk, end_);
}
catch (...) {
/* TODO:
* - Destruct data in previous chunk.
* - Free newly allocated chunk.
* - Reset `end_`. */
throw;
}
end_ += copy_to_next_chunk;
}
class Iterator {
private:
using iterator_category = std::forward_iterator_tag;
using value_type = T;
using pointer = const T *;
using reference = const T &;
const T *begin_;
const T *current_;
const T *end_;
int64_t span_index_;
const ChunkedList *chunked_list_;
friend ChunkedList;
public:
constexpr Iterator &operator++()
{
current_++;
if (current_ == end_) {
span_index_++;
if (const std::optional<Span<T>> span = chunked_list_->get_span(span_index_)) {
begin_ = span.data();
current_ = begin_;
end_ = begin_ + span.size();
}
}
}
constexpr friend bool operator!=(const Iterator &a, const Iterator &b)
{
BLI_assert(a.chunked_list_ == b.chunked_list_);
return a.current_ == b.current_;
}
constexpr const T &operator*() const
{
return *current_;
}
};
private:
void ensure_space_for_one()
{
if (UNLIKELY(end_ >= capacity_end_)) {
this->add_chunk(1);
}
}
BLI_NOINLINE void add_chunk(const int64_t min_chunk_size)
{
int64_t new_chunk_size = min_chunk_size;
T *new_chunk_begin;
if (alloc_info_ == nullptr) {
math::max_inplace(new_chunk_size, std::max<int64_t>(InlineBufferCapacity * 2, 8));
const size_t allocation_size = sizeof(AllocInfo) +
sizeof(T) * static_cast<size_t>(new_chunk_size);
void *buffer = allocator_.allocate(allocation_size, alignof(AllocInfo), __func__);
alloc_info_ = new (buffer) AllocInfo();
new_chunk_begin = static_cast<T *>(POINTER_OFFSET(buffer, sizeof(AllocInfo)));
}
else {
math::max_inplace(new_chunk_size,
std::min<int64_t>(alloc_info_->spans.last().size() * 2, 4096));
const size_t allocation_size = sizeof(T) * static_cast<size_t>(new_chunk_size);
new_chunk_begin = static_cast<T *>(
allocator_.allocate(allocation_size, alignof(T), __func__));
}
MutableSpan<T> new_chunk{new_chunk_begin, new_chunk_size};
alloc_info_->spans.append(new_chunk);
end_ = new_chunk.data();
capacity_end_ = new_chunk.data() + new_chunk_size;
}
};
} // namespace blender

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@@ -1,46 +0,0 @@
/* SPDX-License-Identifier: GPL-2.0-or-later */
#pragma once
/** \file
* \ingroup bli
*
* A `blender::VectorList` is a dynamically growing ordered container for values of type T.
* It is *not* guaranteed that all values will be stored in one contiguous array. Instead, multiple
* arrays may be used.
*
* Comparison to `blender::Vector`:
* - `VectorList` has better performance when appending many elements, because it does not have to
* move existing values.
* - This also means that `VectorList` can be used with types that cannot be moved.
* - A `VectorList` can not be indexed efficiently. So while the container is ordered, one can not
* efficiently get the value at a specific index.
* - Iterating over a `VectorList` is a little bit slower, because it may have to iterate over
* multiple arrays. That is likely negligible in most cases.
*
* `VectorList` should be used instead of `Vector` when the following two statements are true:
* - The elements do not have to be in a contiguous array.
* - The elements do not have to be accessed with an index.
*/
#include "BLI_allocator.hh"
#include "BLI_memory_utils.hh"
namespace blender {
template<typename T> struct VectorListChunk {
/** Start of this chunk. */
T *begin;
/** End of this chunk. */
T *capacity_end;
};
template<typename T,
int64_t InlineBufferCapacity = default_inline_buffer_capacity(sizeof(T)),
typename Allocator = GuardedAllocator>
class VectorList {
T *current_end_;
T *current_capacity_end_;
VectorListChunk *current_chunk_;
};
} // namespace blender

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@@ -330,7 +330,7 @@ set(SRC
BLI_uvproject.h
BLI_vector.hh
BLI_vector_adaptor.hh
BLI_vector_list.hh
BLI_chunked_list.hh
BLI_vector_set.hh
BLI_vector_set_slots.hh
BLI_virtual_array.hh
@@ -434,6 +434,7 @@ if(WITH_GTESTS)
tests/BLI_bit_vector_test.cc
tests/BLI_bitmap_test.cc
tests/BLI_bounds_test.cc
tests/BLI_chunked_list_test.cc
tests/BLI_color_test.cc
tests/BLI_cpp_type_test.cc
tests/BLI_delaunay_2d_test.cc
@@ -495,7 +496,6 @@ if(WITH_GTESTS)
tests/BLI_uuid_test.cc
tests/BLI_vector_set_test.cc
tests/BLI_vector_test.cc
tests/BLI_vector_list_test.cc
tests/BLI_virtual_array_test.cc
tests/BLI_exception_safety_test_utils.hh

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@@ -1,6 +1,6 @@
/* SPDX-License-Identifier: Apache-2.0 */
#include "BLI_vector_list.hh"
#include "BLI_chunked_list.hh"
#include "testing/testing.h"
namespace blender::tests {