#include <AtomicMWMRQueue.hpp>
Classes | |
| union | SIndexes |
Public Types | |
| typedef AtomicQueue< T >::size_type | size_type |
 Public Types inherited from RTT::internal::AtomicQueue< T > | |
| typedef unsigned int | size_type |
Public Member Functions | |
| AtomicMWMRQueue (unsigned int size) | |
| size_type | capacity () const |
| void | clear () |
| bool | dequeue (T &result) |
| bool | enqueue (const T &value) |
| const T | front () const |
| bool | isEmpty () const |
| bool | isFull () const |
| size_type | size () const |
| ~AtomicMWMRQueue () | |
| Public Member Functions inherited from RTT::internal::AtomicQueue< T > | |
| virtual | ~AtomicQueue () |
Private Types | |
| typedef T | C |
| typedef C *volatile | CacheObjType |
| typedef volatile C * | CachePtrType |
| typedef C * | PtrType |
| typedef C | ValueType |
Private Member Functions | |
| AtomicMWMRQueue (const AtomicQueue< T > &) | |
| CachePtrType | propose_r () |
| CachePtrType | propose_w () |
| CachePtrType | recover_r () const |
Private Attributes | |
| CachePtrType | _buf |
| volatile SIndexes | _indxes |
| const int | _size |
Detailed Description
template<class T>
class RTT::internal::AtomicMWMRQueue< T >
Create an atomic, non-blocking single ended queue (FIFO) for storing a pointer to T. It is a Many Readers, Many Writers implementation based on the atomic Compare And Swap instruction. Any number of threads may access the queue concurrently.
This queue tries to obey strict ordering, but under high contention of reads interfering writes, one or more elements may be dequeued out of order. For this reason, size() is expensive to accurately calculate the size.
Due to the same limitations, it is possible that the full capacity of the queue is not used (simulations show seldomly an off by one element if capacity==10) and that isFull() returns true, while size() < capacity().
- Warning
- You can not store null pointers.
- Parameters
-
T The pointer type to be stored in the Queue. Example : AtomicQueue< A* > is a queue of pointers to A.
Definition at line 71 of file AtomicMWMRQueue.hpp.
Member Typedef Documentation
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private |
Definition at line 74 of file AtomicMWMRQueue.hpp.
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private |
Definition at line 76 of file AtomicMWMRQueue.hpp.
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private |
Definition at line 75 of file AtomicMWMRQueue.hpp.
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private |
Definition at line 78 of file AtomicMWMRQueue.hpp.
| typedef AtomicQueue<T>::size_type RTT::internal::AtomicMWMRQueue< T >::size_type |
Definition at line 185 of file AtomicMWMRQueue.hpp.
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private |
Definition at line 77 of file AtomicMWMRQueue.hpp.
Constructor & Destructor Documentation
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private |
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inline |
Create an AtomicQueue with queue size size.
- Parameters
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size The size of the queue, should be 1 or greater.
Definition at line 191 of file AtomicMWMRQueue.hpp.
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inline |
Definition at line 198 of file AtomicMWMRQueue.hpp.
Member Function Documentation
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inlinevirtual |
Return the maximum number of items this queue can contain.
Implements RTT::internal::AtomicQueue< T >.
Definition at line 232 of file AtomicMWMRQueue.hpp.
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inlinevirtual |
Clear all contents of the Queue and thus make it empty.
Implements RTT::internal::AtomicQueue< T >.
Definition at line 305 of file AtomicMWMRQueue.hpp.
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inlinevirtual |
Dequeue an item.
- Parameters
-
value The value dequeued.
- Returns
- false if queue is empty, true if dequeued.
Implements RTT::internal::AtomicQueue< T >.
Definition at line 279 of file AtomicMWMRQueue.hpp.
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inlinevirtual |
Enqueue an item.
- Parameters
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value The value to enqueue, not zero.
- Returns
- false if queue is full or value is zero, true if queued.
Implements RTT::internal::AtomicQueue< T >.
Definition at line 259 of file AtomicMWMRQueue.hpp.
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inlinevirtual |
Return the next to be read value.
Implements RTT::internal::AtomicQueue< T >.
Definition at line 297 of file AtomicMWMRQueue.hpp.
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inlinevirtual |
Inspect if the Queue is empty.
- Returns
- true if empty, false otherwise.
Implements RTT::internal::AtomicQueue< T >.
Definition at line 221 of file AtomicMWMRQueue.hpp.
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inlinevirtual |
Inspect if the Queue is full.
- Returns
- true if full, false otherwise.
Implements RTT::internal::AtomicQueue< T >.
Definition at line 207 of file AtomicMWMRQueue.hpp.
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inlineprivate |
Atomic advance and wrap of the Read pointer. Return the data position or zero if queue is empty.
Definition at line 158 of file AtomicMWMRQueue.hpp.
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inlineprivate |
Atomic advance and wrap of the Write pointer. Return the old position or zero if queue is full.
Definition at line 132 of file AtomicMWMRQueue.hpp.
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inlineprivate |
The loose ordering may cause missed items in our queue which are not pointed at by the read pointer. This function recovers such items from _buf.
- Returns
- zero if nothing to recover, the location of a lost item otherwise.
Definition at line 105 of file AtomicMWMRQueue.hpp.
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inlinevirtual |
Return the exact number of elements in the queue. This is slow because it scans the whole queue.
Implements RTT::internal::AtomicQueue< T >.
Definition at line 242 of file AtomicMWMRQueue.hpp.
Member Data Documentation
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private |
The pointer to the buffer can be cached, the contents are volatile.
Definition at line 90 of file AtomicMWMRQueue.hpp.
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The indexes are packed into one double word. Therefore the read and write index can be read and written atomically.
Definition at line 96 of file AtomicMWMRQueue.hpp.
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private |
Definition at line 73 of file AtomicMWMRQueue.hpp.
The documentation for this class was generated from the following file: