{"id":13729620,"url":"https://github.com/tower120/trackable_ptr","last_synced_at":"2026-02-01T23:40:48.619Z","repository":{"id":103798245,"uuid":"101922111","full_name":"tower120/trackable_ptr","owner":"tower120","description":"Smart pointer for any movable objects. 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When `trackable` object moved/destroyed, `trackable_ptr`s updated with new object's location.\n\nAllow to have stable pointer on any movable object (in single-threaded environment). Objects may be stack allocated.\n\nHeader only. You need only \"include\" folder.\n\n**Warning!** Performance-wise it is not faster then using heap allocated objects (probably due to size grow). See benchmarks, your mileage may vary.\n\n```c++\nstruct Data{\n    int x,y,z;\n};\n\nstd::vector\u003c unique_trackable\u003cData\u003e \u003e list1;\n\nlist1.emplace_back();\n\n  trackable_ptr\u003cData\u003e ptr {list1.back()};\t//  store pointer to element\n\nlist1.emplace_back();\nlist1.emplace_back();\nlist1.emplace_back();\nlist1.emplace_back();\n// list 1 now uses another memory chuck. All pointers/iterators invalidated.\n\n// ptr still alive and accessible;\nstd::cout \u003c\u003c ptr-\u003ex;\n```\n\n```cpp\nstruct Box;\n\nstruct Corner{\n    explicit Corner(Box* box) : box(box) {}\n\n    trackable_ptr\u003cBox\u003e box;\n    int x = 0;\n    int y = 0;\n};\n\nstruct Box : trackable_base {\n    Corner lt{this};\n    Corner rb{this};\n};\n\nstd::vector\u003cBox\u003e boxes;\n\n// Box can be moved around. Corner::box always valid.\n// trackable_ptr\u003cBox\u003e can be stored in lambda callback.\n\nBox\u0026 active_box = boxes[i];\non_some_event([box = trackable_ptr\u003cBox\u003e(\u0026active_box)](){\n    if (!box) return;\n    std::cout \u003c\u003c box-\u003elt.x;\n});\n```\n\n#### Behavior\n\nOn `trackable` destruction - all `trackable_ptr`s becomes nullptr.\n\nOn `trackable` move - all `trackable_ptr`s updates with new object location.\n\nOn `trackable` copy - `trackable_ptr`s unaffected.\n\n#### `trackable_base`\n\nInherit this, if you want your class to be compatible with `trackable_ptr`.\n\n```cpp\nstruct MyClass : trackable_base {}\n\nMyClass m;\ntrackable_ptr\u003cMyClass\u003e p = \u0026m;\n```\n\n#### `trackable\u003cT\u003e`\n\n```cpp\ntrackable\u003cint\u003e i;\ntrackable_ptr\u003cint\u003e p = \u0026i;\n\nauto i2 = std::move(i);\nassert(p.get() == i2.get());\n```\n\nFor the sake of sanity, `trackable\u003cconst T\u003e` is forbidden, use `const trackable\u003cT\u003e` instead.\n\n * `trackable()` - construct object with default constructor, if possible.\n * `trackable(T\u0026\u0026)` - conversion constructor.\n * `trackable(Args\u0026\u0026... args)` - in-place construct object.\n * `trackable(trackable\u0026\u0026 other)`\n * `trackable(const trackable\u0026)`\n * `trackable\u0026 operator=(trackable\u0026\u0026)`\n * `trackable\u0026 operator=(const trackable\u0026)`\n * `T* get()` - return object pointer.\n * `const T* get() const`\n * `T* operator-\u003e()`\n * `const T* operator-\u003e() const`\n * `T\u0026 operator*()`\n * `const T\u0026 operator*() const`\n * `~trackable()` - update all `trackable_ptr`'s with new nullptr.\n\n#### `unique_trackable\u003cT\u003e`\n\nSame as `trackable`, but move-only.\n\nUseful for use in containers. For example, it is not required for `std::vector` implementation to use move instead copy, when both copy and move constructor are available. Though all tested implementations currently prefer move, whenever possible.\n\n\n#### `trackable_ptr\u003cT\u003e`\n\n * `trackable_ptr()` - construct with nullptr\n * `trackable_ptr(T*)`\n * `trackable_ptr(trackable\u003cT\u003e*)`\n * `auto* get_trackable() const` - return address of `trackable`, which holds object (return `get()` otherwise).\n * `operator bool() const` - return true if not nullptr\n * `T* get() const` - return object pointer.\n * `T* operator-\u003e() const`\n * `T\u0026 operator*() const`\n * `~trackable_ptr()` - exclude this from trackers list.\n\n\n#### \"trackable_ptr_extensions.h\"\n\n```c++\n#include \u003cvector\u003e\n\n#include \u003ctower120/trackable_ptr_extensions.h\u003e\n\nint main() {\n    std::vector\u003ctrackable\u003cint\u003e\u003e vec = {1, 2, 3, 4};\n\n    trackable_ptr\u003cint\u003e p{vec.begin()};\n\n    assert(get_iterator(vec, p) == vec.begin());\n\n    return 0;\n}\n```\nWork with contiguous containers only.\n\n * `in_container(const Container\u0026, const trackable_ptr\u003cT\u003e \u0026)` - check if trackable_ptr stored inside contiguous container.\n * `get_index(const Container\u0026, const trackable_ptr\u003cT\u003e\u0026)` - return index of element in contiguous container. trackable_ptr must exists inside contiguous container.\n * `get_iterator(Container\u0026\u0026, const trackable_ptr\u003cT\u003e \u0026)` - return iterator of element in contiguous container. if trackable_ptr does not exists inside contiguous container, return end().\n\n\n### Overhead\n * 1 ptr for `trackable`\n * 3 ptr for `trackable_ptr`\n * O(n) complexity for moving/destroying `trackable`. Where n = `tracker_ptr`s per `trackable`\n * O(1) complexity for moving/destroying `trackable_ptr`\n","funding_links":[],"categories":["C++"],"sub_categories":[],"project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Ftower120%2Ftrackable_ptr","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Ftower120%2Ftrackable_ptr","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Ftower120%2Ftrackable_ptr/lists"}