e955c94ed3
Listing the "Blender Foundation" as copyright holder implied the Blender Foundation holds copyright to files which may include work from many developers. While keeping copyright on headers makes sense for isolated libraries, Blender's own code may be refactored or moved between files in a way that makes the per file copyright holders less meaningful. Copyright references to the "Blender Foundation" have been replaced with "Blender Authors", with the exception of `./extern/` since these this contains libraries which are more isolated, any changed to license headers there can be handled on a case-by-case basis. Some directories in `./intern/` have also been excluded: - `./intern/cycles/` it's own `AUTHORS` file is planned. - `./intern/opensubdiv/`. An "AUTHORS" file has been added, using the chromium projects authors file as a template. Design task: #110784 Ref !110783.
123 lines
2.5 KiB
C++
123 lines
2.5 KiB
C++
/* SPDX-FileCopyrightText: 2023 Blender Authors
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*
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* SPDX-License-Identifier: GPL-2.0-or-later */
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#pragma once
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#include <algorithm>
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#include "BLI_vector.hh"
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namespace blender {
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/**
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* A VectorList is a vector of vectors.
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*
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* VectorList can be used when:
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*
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* 1) Don't know up front the number of elements that will be added to the list. Use array or
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* vector.reserve when known up front.
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*
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* 2) Number of reads/writes doesn't require sequential access
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* of the whole list. A vector ensures memory is sequential which is fast when reading, writing can
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* have overhead when the reserved memory is full.
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*
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* When a VectorList reserved memory is full it will allocate memory for the new items, breaking
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* the sequential access. Within each allocated memory block the elements are ordered sequentially.
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*/
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template<typename T, int64_t CapacityStart = 32, int64_t CapacitySoftLimit = 4096>
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class VectorList {
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public:
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using UsedVector = Vector<T, 0>;
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private:
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/**
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* Contains the individual vectors. There must always be at least one vector
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*/
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Vector<UsedVector> vectors_;
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public:
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VectorList()
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{
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this->append_vector();
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}
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void append(const T &value)
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{
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this->append_as(value);
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}
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void append(T &&value)
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{
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this->append_as(std::move(value));
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}
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template<typename ForwardT> void append_as(ForwardT &&value)
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{
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UsedVector &vector = this->ensure_space_for_one();
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vector.append_unchecked_as(std::forward<ForwardT>(value));
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}
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UsedVector *begin()
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{
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return vectors_.begin();
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}
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UsedVector *end()
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{
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return vectors_.end();
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}
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const UsedVector *begin() const
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{
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return vectors_.begin();
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}
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const UsedVector *end() const
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{
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return vectors_.end();
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}
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T &last()
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{
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return vectors_.last().last();
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}
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int64_t size() const
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{
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int64_t result = 0;
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for (const UsedVector &vector : *this) {
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result += vector.size();
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}
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return result;
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}
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private:
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UsedVector &ensure_space_for_one()
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{
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UsedVector &vector = vectors_.last();
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if (LIKELY(!vector.is_at_capacity())) {
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return vector;
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}
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this->append_vector();
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return vectors_.last();
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}
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void append_vector()
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{
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const int64_t new_vector_capacity = this->get_next_vector_capacity();
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vectors_.append({});
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vectors_.last().reserve(new_vector_capacity);
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}
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int64_t get_next_vector_capacity()
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{
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if (vectors_.is_empty()) {
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return CapacityStart;
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}
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return std::min(vectors_.last().capacity() * 2, CapacitySoftLimit);
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}
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};
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} // namespace blender
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