Sybren A. Stüvel
a4d2ae12a5
This commit introduces `ConstListBaseWrapper`, to allow easy iteration over
`const ListBase *` in C++ code.
Basically `ListBaseWrapper` was renamed to `ListBaseWrapperTemplate`, and
got a new template parameter `LB`. The new `ListBaseWapper` class has `LB=ListBase`,
whereas `ConstListBaseWrapper` has `LB=const ListBase`.
Also in this commit is one use of `ConstListBaseWrapper` to make sure the
templated code is actually expanded & compiled.
Example use:
```cpp
for (const bDeformGroup *dg : ConstListBaseWrapper<bDeformGroup>(defbase)) {
...
}
```
Pull Request: blender/blender#105464
103 lines
2.1 KiB
C++
103 lines
2.1 KiB
C++
/* SPDX-License-Identifier: GPL-2.0-or-later */
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#pragma once
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/** \file
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* \ingroup bli
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*
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* `blender::ListBaseWrapper` is a typed wrapper for the #ListBase struct. That makes it safer and
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* more convenient to use in C++ in some cases. However, if you find yourself iterating over a
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* linked list a lot, consider to convert it into a vector for further processing. This improves
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* performance and debug-ability.
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*/
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#include "BLI_listbase.h"
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#include "DNA_listBase.h"
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namespace blender {
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template<typename LB, typename T> class ListBaseWrapperTemplate {
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private:
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LB *listbase_;
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public:
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ListBaseWrapperTemplate(LB *listbase) : listbase_(listbase)
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{
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BLI_assert(listbase);
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}
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ListBaseWrapperTemplate(LB &listbase) : ListBaseWrapperTemplate(&listbase)
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{
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}
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class Iterator {
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private:
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LB *listbase_;
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T *current_;
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public:
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Iterator(LB *listbase, T *current) : listbase_(listbase), current_(current)
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{
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}
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Iterator &operator++()
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{
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/* Some types store `next/prev` using `void *`, so cast is necessary. */
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current_ = static_cast<T *>(current_->next);
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return *this;
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}
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Iterator operator++(int)
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{
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Iterator iterator = *this;
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++(*this);
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return iterator;
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}
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bool operator!=(const Iterator &iterator) const
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{
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return current_ != iterator.current_;
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}
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T *operator*() const
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{
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return current_;
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}
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};
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Iterator begin() const
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{
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return Iterator(listbase_, static_cast<T *>(listbase_->first));
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}
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Iterator end() const
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{
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return Iterator(listbase_, nullptr);
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}
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T *get(uint index) const
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{
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void *ptr = BLI_findlink(listbase_, index);
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BLI_assert(ptr);
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return static_cast<T *>(ptr);
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}
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int64_t index_of(const T *value) const
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{
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int64_t index = 0;
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for (T *ptr : *this) {
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if (ptr == value) {
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return index;
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}
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index++;
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}
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BLI_assert(false);
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return -1;
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}
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};
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template<typename T> using ListBaseWrapper = ListBaseWrapperTemplate<ListBase, T>;
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template<typename T> using ConstListBaseWrapper = ListBaseWrapperTemplate<const ListBase, const T>;
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} /* namespace blender */
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