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Packet_Queue< Packet > Class Template Reference

Inheritance diagram for Packet_Queue< Packet >:

Detailed Description

template<class Packet>
class Packet_Queue< Packet >

Packet Queues are a very important design pattern in embedded and real-time systems. Here we implement the Packet Queue class as a very thin wrapper over the STL queue container adaptor.

STL queue container adaptor supports the standard queue operations, viz. add to queue, remove from queue. STL allows you to specify the underlying container used for implementing the queue. By changing one line of code you could change from a linked list implementation to an array like double ended queue In this example we will be implementing the queue using the list. This organizes the message queue as a linked list of nodes containing pointers to the message.

Definition at line 29 of file Packet_Queue.h.

Public Member Functions
void	Add (Packet *p_Packet)
	Add a message to the end of the queue.
Packet *	Remove ()
	Remove a message from the head of the queue.
size_t	Get_Length () const
	Obtain the length of the queue.
Private Types
typedef queue< Packet *, list< Packet * > >	Packet_Queue_Type
	Declaring the type for a queue.
Private Attributes
Packet_Queue_Type	m_packet_Queue
	Declaration of the message queue based on the type declaration Packet_Queue_Type.

Member Typedef Documentation

template<class Packet> typedef queue<Packet *, list<Packet *> > Packet_Queue< Packet >::Packet_Queue_Type [private]

Declaring the type for a queue. Here we are specifying a queue of message pointers organized as a linked list. Definition at line 33 of file Packet_Queue.h.

Member Function Documentation

template<class Packet> void Packet_Queue< Packet >::Add (  Packet *  p_Packet  )  [inline]

Add a message to the end of the queue. The push method supported by queue is used to add the message to the end of the queue. Note that all the memory management associated with the queue container management is taken care by STL. Parameters: p_Packet  Pointer to the message that needs to be added to the queue. Definition at line 45 of file Packet_Queue.h. 00046 { 00047 // Insert the element at the end of the queue 00048 m_packet_Queue.push(p_Packet); 00049 }

template<class Packet> Packet* Packet_Queue< Packet >::Remove (   )  [inline]

Remove a message from the head of the queue. Returns NULL if no message is found. This method performs the following steps: Make sure that the queue is not empty If so, get a pointer to the message at the head of the queue. Now pop the message out of the queue. retval Packet Pointer to the message removed from the queue. Returns NULL if no message is found in the queue. Definition at line 61 of file Packet_Queue.h. 00062 { 00063 Packet *p_Packet = NULL; 00064 00065 // Check if the message queue is not empty 00066 if (!m_packet_Queue.empty()) 00067 { 00068 // Queue is not empty so get a pointer to the 00069 // first message in the queue 00070 p_Packet = m_packet_Queue.front(); 00071 00072 // Now remove the pointer from the message queue 00073 m_packet_Queue.pop(); 00074 } 00075 return p_Packet; 00076 }

template<class Packet> size_t Packet_Queue< Packet >::Get_Length (   )  const [inline]

Obtain the length of the queue. The size method is used to obtain the queue length. Return values: int  Total number of messages in the queue. Definition at line 81 of file Packet_Queue.h. 00082 { 00083 return m_packet_Queue.size(); 00084 }

• Packet_Queue.h

Generated on Sun Feb 13 21:30:33 2005 for Object Oriented Design Examples by 1.3.4

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