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81 lines
2.3 KiB
Markdown
81 lines
2.3 KiB
Markdown
---
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title: "callback_service"
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---
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{{< callout type="info">}}
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Header: `callback_service.h`
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{{< /callout >}}
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This template class allows easier integration of 'C' style events (such as interrupt vectors) and C++ handlers.
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It can allow abstraction between low level events such as interrupts and their application dependent handlers.
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The handlers may be any combination of global, static or member functions.
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It utilises the templated function wrapper.
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The callbacks are identified by an id. The values of the ids must range from zero or a specified offset, up to the maximum number of specified callbacks. Calling an unused callback id will either do nothing or, if the user has specified a handler, call this with the id of the callback.
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There are functions that use both runtime and compile time checks of the callback id.
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Compile time is preferable.
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## Member functions
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```cpp
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template <const size_t RANGE, const size_t OFFSET = 0U>
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etl::callback_service
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```
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`RANGE` The id range of the callbacks.
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`OFFSET` The starting id for the range.
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It can allow abstraction between low level events such as interrupts and their application dependent handlers.
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```cpp
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callback_service()
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```
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Sets all of the callbacks to route to the unhandled callback.
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Sets the unhandled callback to default (do nothing).
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---
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```cpp
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template <const size_t ID>
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void register_callback(etl::ifunction<size_t>& callback)
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```
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Registers callback with the id specified in the template parameter.
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A compile time error will occur if the id is out of range.
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---
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```cpp
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void register_callback(size_t id, etl::ifunction<size_t>& callback)
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```
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Registers callback with the id specified in the template parameter.
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The registration will be ignored if the id is out of range.
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---
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```cpp
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void register_unhandled_callback(etl::ifunction<size_t>& callback)
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```
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Registers the callback to be used for unhandled ids.
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---
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```cpp
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template <const size_t ID>
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void callback()
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```
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Calls the callback associated with the id.
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Calls the unhandled callback if the id has not been registered.
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A compile time error will occur if the id is out of range.
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---
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```cpp
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void callback(const size_t id)
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```
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Calls the callback associated with the id.
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Calls the unhandled callback if the id has not been registered or if is out of range.
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## Example
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See the example project in `examples\FunctionInterruptSimulation`.
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