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/**************************************************************************/
/* */
/* Copyright (c) 2001, 2010 NoMachine, http://www.nomachine.com/. */
/* */
/* NXCOMP, NX protocol compression and NX extensions to this software */
/* are copyright of NoMachine. Redistribution and use of the present */
/* software is allowed according to terms specified in the file LICENSE */
/* which comes in the source distribution. */
/* */
/* Check http://www.nomachine.com/licensing.html for applicability. */
/* */
/* NX and NoMachine are trademarks of Medialogic S.p.A. */
/* */
/* All rights reserved. */
/* */
/**************************************************************************/
#ifndef SequenceQueue_H
#define SequenceQueue_H
inline int SequenceNumber_x_gt_y(unsigned int x, unsigned int y)
{
// For two sequence numbers x and y, determine whether (x > y).
// Sequence numbers are the trailing 16 bits of a bigger number:
// need to handle wraparound, e.g. 0 is 65536, just after 65535.
if (x != (x & 0x00ffff)) return 0;
if (y != (y & 0x00ffff)) return 0;
// Closeness when comparison makes sense: arbitrarily set at 16*1024
if ((x > y) && ((x-y) < 16*1024)) return 1;
// Wrapped value
unsigned int w = x + 64*1024;
// We know that w>y but test left for symmetry
if ((w > y) && ((w-y) < 16*1024)) return 1;
return 0;
}
//
// List of outstanding request messages which
// are waiting for a reply. This class is used
// in X client and server channels to correlate
// the replies sequence numbers to the original
// request type.
//
class SequenceQueue
{
public:
SequenceQueue();
virtual ~SequenceQueue();
void push(unsigned short int sequence, unsigned char opcode,
unsigned int data1 = 0, unsigned int data2 = 0,
unsigned int data3 = 0);
int peek(unsigned short int &sequence, unsigned char &opcode);
int peek(unsigned short int &sequence, unsigned char &opcode,
unsigned int &data1, unsigned int &data2,
unsigned int &data3);
int pop(unsigned short int &sequence, unsigned char &opcode,
unsigned int &data1, unsigned int &data2,
unsigned int &data3);
int pop(unsigned short int &sequence, unsigned char &opcode)
{
unsigned int data1, data2, data3;
return pop(sequence, opcode, data1, data2, data3);
}
int length()
{
return length_;
}
private:
struct RequestSequence
{
unsigned short int sequence;
unsigned char opcode;
unsigned int data1;
unsigned int data2;
unsigned int data3;
};
RequestSequence *queue_;
unsigned int size_;
unsigned int length_;
unsigned int start_;
unsigned int end_;
};
#endif /* SequenceQueue_H */
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