168 lines
4.2 KiB
C++
168 lines
4.2 KiB
C++
/*
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* spacket.h
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*
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* Copyright (c) 1997-98 by Microsoft Corporation, Redmond, WA
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*
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* Abstract:
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* This is the interface file for the SimplePacket class. Instances of this
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* class represent Protocol Data Units (PDUs) as they flow through the
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* system. Objects of this class can not be instantiated, because it's a
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* pure virtual class. It exists only to be inherited from. The Packet
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* and DataPacket classes inherit from this one.
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*
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* A packet object can be created in 2 different ways. It can be created
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* with either decoded data or encoded data. During instantiation, the
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* new packet object will calculate how much memory it will need to
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* hold both the encoded and decoded data, and attempts to allocate that
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* memory. If it cannot, then it will report an error, and the newly
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* created object should be immediately destroyed. If the allocations are
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* successful, then the packet will report success, but WILL NOT yet put
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* any data into those allocated buffers.
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*
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* When a Lock message is sent to the object, it will put encoded
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* data into the pre-allocated encode buffer. If the packet was created
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* with decoded data, then this will entail an encode operation. However,
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* if the packet was created with encoded data, then it is smart enough
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* to just COPY the encoded data into the internal buffer, thus avoiding
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* the overhead associated with the encode operation.
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*
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* When a Lock message is sent to the object, it will put decoded
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* data into the pre-allocated decode buffer. If the packet was created
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* with encoded data, then this will entail a decode operation. However,
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* if the packet was created with decoded data, then it is smart enough
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* to just COPY the decoded data into the internal buffer, thus avoiding
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* the overhead associated with the decode operation.
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*
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* Caveats:
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* None.
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*
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* Authors:
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* Christos Tsollis
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*/
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#ifndef _SIMPLE_PACKET_
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#define _SIMPLE_PACKET_
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/*
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* This typedef is used to define possible return values from various public
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* member functions of this class.
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*/
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typedef enum
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{
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PACKET_NO_ERROR,
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PACKET_MALLOC_FAILURE,
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PACKET_INCOMPATIBLE_PROTOCOL
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} PacketError;
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typedef PacketError * PPacketError;
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/*
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* Definition of class Packet.
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*/
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class SimplePacket
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{
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public:
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SimplePacket(BOOL fPacketDirectionUp);
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virtual ~SimplePacket(void) = 0;
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Void Lock(void)
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{
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InterlockedIncrement(&lLock);
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ASSERT (lLock > 0);
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};
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UINT GetEncodedDataLength(void)
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{
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return (Encoded_Data_Length);
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};
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void Unlock(void);
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LPBYTE GetEncodedData (void)
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{
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ASSERT (m_EncodedPDU);
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return m_EncodedPDU;
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};
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virtual PVoid GetDecodedData(void) = 0;
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virtual BOOL IsDataPacket (void) = 0;
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virtual int GetPDUType (void) = 0;
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protected:
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long lLock;
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LPBYTE m_EncodedPDU; // The encoded data pdu.
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BOOL Packet_Direction_Up;
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UINT Encoded_Data_Length; // the size of the whole encoded PDU.
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};
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/*
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* SimplePacket ()
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*
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* Functional Description:
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* This is the default constructor of a SimplePacket. It initializes
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* the few member variables to default values.
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*
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/*
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* ~SimplePacket ()
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*
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* Functional Description:
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* Destructor for the SimplePacket class.
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*
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* Formal Parameters:
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* None.
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*
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* Return Value:
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* None.
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*
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* Side Effects:
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* None.
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*
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* Caveats:
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* None.
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*/
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/*
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* GetEncodedData ()
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*
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* Functional Description:
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* The GetEncodedData method returns a pointer to the encoded data
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* buffer. If the Packet object is oriented differently than desired
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* by the caller of this method, then the packet coder is called to
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* reverse the direction of the PDU.
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*
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* Formal Parameters:
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* None.
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*
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* Return Value:
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* A pointer to the encoded data. If an encoding error occurs, this
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* method will return NULL.
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*
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* Side Effects:
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* None.
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*
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* Caveats:
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* None.
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*/
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/*
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* GetDecodedData ()
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*
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* Functional Description:
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* The GetDecodedData method returns a pointer to the decoded data
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* buffer.
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*
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* Formal Parameters:
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* None.
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*
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* Return Value:
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* A pointer to the decoded data. If an decoding error occurs, this
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* method will return NULL.
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*
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* Side Effects:
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* None.
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*
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* Caveats:
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* None.
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*/
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#endif
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