Queues¶
FIFO¶
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class
fifo(max_size)¶ Fifo class
Creates a new First-In-First-Out Queue with at most max_size elements
Arguments: - max_size (int) – Maximum queue size
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fifo.flush()¶ Deletes the entire queue removing all elements.
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fifo.peek()¶ Returns one element of the queue without removing the element.
Returns: any – The element or null on failure
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fifo.pull()¶ Extracts one element of the queue. The element will be removed from the queue.
Returns: any – The element or null on failure.
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fifo.push(value)¶ Adds a new element to the queue. If max_size is reached no element will be added.
Arguments: - value (any) – The value to add
Returns: boolean – true if current queue size isn’t greater than max_size. Otherwise false.
Asynchronous Fifo¶
New in version 0.2.0.
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class
AsyncFifo(max_size)¶ Asynchronous fifo implementation
Arguments: - max_size (int) – Maximum queue size
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AsyncFifo.flush()¶ Flushes the queue and emits an flush event
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AsyncFifo.on(ev, callback)¶ Adds a new event listener
Arguments: - ev (string) – Event name
- callback (callback) – which should be attached to the queue.
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AsyncFifo.pull()¶ Pulls a value synchronously, if the queue is empty, an empty event is emitted
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AsyncFifo.push(value)¶ Pushes a new value to the queue and emits an data event or an full event if the maximum queue size is reached.
Arguments: - value (any) – Value which should be enqueued.
Fifo Events¶
The queue emits the following events:
- data
- The data event is emitted if a new item is available to be processed If multiple listeners are attached to this event, only one listener can pull the same item. The callback gets a reference to the fifo queue. You can call pull on the reference to retrieve the last enqueued item.
- full
- This emit is emitted if the queue’s maximum size is reached.
- empty
- This event is emitted if pull is called and there are no items available.
- flush
- This event is emitted if someone flushes the queue.
LIFO (Stack)¶
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class
lifo(max_size)¶ Represents a LIFO - Queue (Stack)
Creates a Last-In-First-Out Queue with at most max_size elements.
Arguments: - max_size (int) – Maximum queue size
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lifo.flush()¶ Flushes the entire stack
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lifo.peek()¶ Returns the last element, but does not delete it from the stack.
Returns: any – the value.
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lifo.pop()¶ Pops one element from the stack
Returns: any – the value.
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lifo.push(value)¶ Pushes on element ot the stack.
Arguments: - value (any) – The value you want to push to the stack.
Returns: boolean – true if the current stack size doesn’t exceed the maximum stack size.
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lifo.size¶ Returns the current stack size
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class
ArrayStack(max_size)¶ Provides a fast stack as an Array
Creates a new stack with at most max_size elements
Arguments: - max_size (int) – maximum stack size or Infinity for unlimited stacks.
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ArrayStack.flush()¶ Deletes the entire stack
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ArrayStack.peek()¶ Returns the top most element of the stack, but does not delete it.
Returns: any – any element
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ArrayStack.pop()¶ pops one element off the stack.
Returns: any – any element
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ArrayStack.push(val)¶ Pushes a new value to the stack
Arguments: - val (any) – Value which should be pushed to the stack.