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Jack2
1.9.12
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A class to handle several states in a lock-free manner. More...
#include <JackAtomicArrayState.h>
Public Member Functions | |
| T * | ReadCurrentState () |
| Returns the current state : only valid in the RT reader thread. | |
| UInt16 | GetCurrentIndex () |
| Returns the current switch counter. | |
| T * | TrySwitchState (int state) |
| Tries to switch to the next state and returns the new current state (either the same as before if case of switch failure or the new one) | |
| T * | TrySwitchState (int state, bool *result) |
| Tries to switch to the next state and returns the new current state (either the same as before if case of switch failure or the new one) | |
| T * | WriteNextStateStart (int state) |
| Start write operation : setup and returns the next state to update, check for recursive write calls. | |
| T * | WriteNextStateStart (int state, bool *result) |
| void | WriteNextStateStop (int state) |
| Stop write operation : make the next state ready to be used by the RT thread. | |
Protected Member Functions | |
| UInt32 | WriteNextStateStartAux (int state, bool *result) |
| void | WriteNextStateStopAux (int state) |
Protected Attributes | |
| T | fState [3] |
| volatile AtomicArrayCounter | fCounter |
A class to handle several states in a lock-free manner.
Requirement:
- a "current" state
- several possible "pending" state
- an TrySwitchState(int state) operation to atomically switch a "pending" to the "current" state (the pending becomes the current).
The TrySwitchState operation returns a "current" state (either the same if switch fails or the new one, one can know if the switch has succeeded)
- a WriteNextStartState(int state) returns a "pending" state to be written into
- a WriteNextStartStop(int state) make the written "pending" state become "switchable"
Different pending states can be written independantly and concurrently.
GetCurrentIndex() *must* return an increasing value to be able to check reading current state coherency
The fCounter is an array of indexes to access the current and 3 different "pending" states.
WriteNextStateStart(int index) must return a valid state to be written into, and must invalidate state "index" ==> cur state switch.
WriteNextStateStop(int index) makes the "index" state become "switchable" with the current state.
TrySwitchState(int index) must detect that pending state is a new state, and does the switch
ReadCurrentState() must return the state
GetCurrentIndex() must return an index increased each new switch.
WriteNextStateStart(int index1) and WriteNextStateStart(int index2) can be interleaved
[switch counter][index state][index state][cur index]
Definition at line 114 of file JackAtomicArrayState.h.
1.8.13