Ditto

Generic reusable C++ software components for both embedded and general purpose software. Curated with love and care. In contrast with other libraries, it takes advantage of the latest C++20 features and library components. Therefore, it is best used with a recent compiler with C++20 support.

Available components

• Ditto::LinkedList: Implementation of a doubly-linked list. Currently, it is not very suitable for embedded use, it uses new/delete.
• Ditto::Box: Implementation of a non-null owned pointer, similar to std::unique_ptr, but is always valid. When moved, a new object is default constructed in the object that is being moved from.
• Ditto::Pair: Pair implementation. Not much to be seen here.
• Ditto::HashMap: Simple hash map implementation. It uses fixed size buckets and each contains a list to handle hash collisions. Much could be improved in this implementation. Especially to make it more suitable for embedded use. This is still WIP.
• Ditto::LinearMap: More suitable map implementation for embedded systems. It is fully statically allocated and performs linear search for keys so lookup is O(N).
• Ditto::CircularQueue: Implementation of a Circular FIFO Queue statically allocated.
• Ditto::StateMachine: Generic implementation of an FSM where states are represented as an Ditto::static_ptr.
• Ditto::NonNullPtr: Implementation of a pointer that cannot be nullptr. It asserts that the pointer it is constructed from is not null. It does not own the memory, it's just a wrapper over a raw pointer to imply that it cannot be null.
• Ditto::EventLoop: Implementation of an event loop for embedded use. It follows the observer pattern for Events and loops through an event queue distributing events to its subscribers.
• Ditto::Badge: Implements the Badge pattern. Functions taking a Badge object can only be called from the templated class of the Badge, since a badge can only be constructed from this templated class.
• Ditto::Result: Encapsulation of the return type of function. Could either be and Ok value or an Error and has method to find out which one it is and obtain the value.
• Ditto::FixedPoint: Implements a fixed point integer with support for common operations.
• Ditto::ResourceLock: Implements a wrapper of an object and a mutex. The underlying object can only be accessed when the mutex has been locked, ensuring that the access to the resource is always mutually exclusive. It treats all accesses as potentially changing the state of the object, therefore one must also lock for reads even if no other thread is mutating the state of the underlying object.
• Ditto::ReadWriteLock: Implements a similar wrapper to a ResourceLock, but it can acquire many reader locks from any number of threads and be safe because they don't mutate the underlying value. A write lock requires exclusive access and therefore must guarantee that there are no other read or write locks. It makes it possible to lock multiple times in the same thread for reading.
• Ditto::optional: Implements the same abstraction as std::optional with the same API. Makes it available on targets where std::optional is not present. If std::optional is present, Ditto::optional is just an alias to std::optional (if USE_STD_TEMPLATES was defined).
• Ditto::span: Implements the same abstraction as std::span with the same API. Makes it available on targets where std::span is not present. If std::span is present, Ditto::span is just an alias to std::span (if USE_STD_TEMPLATES was defined).
• Ditto::make_enumerated_iter: Makes an enumerated iterator when iterating ordered containers like std::vector, std::array or std::map. The enumerated iterator returns a tuple, being the first element the size_t index of the enumeration and the second element the element of the original iterator of the underlying type. This is useful when you want to iterate using begin and end but also get access to the indexes of the elements.
• Ditto::static_ptr: Data structure that can hold different objects statically. You can think of it as an Ditto::Box<Base> that can hold derived types statically. For that, it needs to know at compile-time what classes could be instantiated, to make sure it reserves enough memory for them, and it is aligned appropriately for all of these derived classes. This is
• particularly useful for embedded systems when we have heavy objects that implement a given interface and are mutually exclusive (They won't be instantiated at the same time). An example for a use case is a screen in a graphics system. When switching screens, all widgets in the previous screen will no longer be used and therefore, all screens could be a Ditto::static_ptr.
• Ditto::SimpleHasher: Simple hasher implementation that leverages CRC32C as a hasher. It can hash an incoming stream of data and satisfies the Hasher concept.
• Ditto::Enum: Enum class that can be a variant of different enum values. Similar to Rust fat enums.
• It features a custom assert implementation that can be overriden by the user.

Using Ditto

This library is distributed with CMake. In order to link your project against it, you can just use it as an external project:

include(FetchContent)

FetchContent_Declare(
  Ditto
    GIT_REPOSITORY https://github.com/Javier-varez/Ditto
    GIT_TAG main)

FetchContent_MakeAvailable(Ditto)

# Now you can link it against your target:
target_link_libraries(<TARGET_NAME> PRIVATE Ditto)

Contributing

Feel free to contribute to this project and open issues. Appreciated contributions include, but are not limited to:

• Bug reports
• Code contributions
• Documentation contributions
• Issues
• Feature requests

Happy coding!