125 lines
2.3 KiB
C
125 lines
2.3 KiB
C
|
// generic queue class
|
||
|
|
// usage:
|
||
|
|
// QueueOf<char *> charq;
|
||
|
|
|
||
|
|
#ifndef _QUEUE_H_
|
||
|
|
#define _QUEUE_H_
|
||
|
|
|
||
|
|
template <class T>
|
||
|
|
class QueueOf
|
||
|
|
{
|
||
|
|
public:
|
||
|
|
QueueOf(): m_maxItems(8),m_iFirst(0),m_iLast(0)
|
||
|
|
{
|
||
|
|
// m_maxItems is always a power of 2
|
||
|
|
m_List = new T [m_maxItems];
|
||
|
|
}
|
||
|
|
|
||
|
|
// returns TRUE if the queue is empty and FALSE otherwise
|
||
|
|
BOOL IsEmpty(void) { return (m_iLast == m_iFirst);}
|
||
|
|
|
||
|
|
// add an element to the tail of the queue
|
||
|
|
// makes a copy of the element
|
||
|
|
BOOL Put(const T &itemT)
|
||
|
|
{
|
||
|
|
int inext;
|
||
|
|
inext = (m_iLast+1)&(m_maxItems-1);
|
||
|
|
|
||
|
|
if (inext == m_iFirst)
|
||
|
|
{
|
||
|
|
// too many items
|
||
|
|
if (!Grow())
|
||
|
|
{
|
||
|
|
|
||
|
|
return FALSE;
|
||
|
|
}
|
||
|
|
inext = (m_iLast+1)&(m_maxItems-1);
|
||
|
|
}
|
||
|
|
|
||
|
|
m_List[m_iLast] = itemT;
|
||
|
|
m_iLast = inext;
|
||
|
|
|
||
|
|
return TRUE;
|
||
|
|
}
|
||
|
|
|
||
|
|
// get the first element in the queue
|
||
|
|
BOOL Get(T *pT)
|
||
|
|
{
|
||
|
|
if (IsEmpty())
|
||
|
|
return FALSE; // nothing in queue
|
||
|
|
else
|
||
|
|
{
|
||
|
|
if (pT)
|
||
|
|
*pT = m_List[m_iFirst];
|
||
|
|
m_iFirst = (m_iFirst+1)&(m_maxItems-1);
|
||
|
|
return TRUE;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
// get the ith element in the queue without removing it
|
||
|
|
BOOL Peek(T *pT, UINT pos=0)
|
||
|
|
{
|
||
|
|
if (pos >= GetCount())
|
||
|
|
return FALSE;
|
||
|
|
else
|
||
|
|
{
|
||
|
|
*pT = m_List[(m_iFirst+pos)&(m_maxItems-1)];
|
||
|
|
return TRUE;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// delete the ith element in the queue (this is not an efficient function!)
|
||
|
|
BOOL Remove(UINT pos)
|
||
|
|
{
|
||
|
|
if (pos >= GetCount())
|
||
|
|
return FALSE;
|
||
|
|
else
|
||
|
|
{
|
||
|
|
int i1 = (m_iFirst+(int)pos)&(m_maxItems-1);
|
||
|
|
int i2 = (i1+1)&(m_maxItems-1);
|
||
|
|
// shift left to fill the gap
|
||
|
|
for (; i2 != m_iLast; i1=i2,i2=(i2+1)&(m_maxItems-1))
|
||
|
|
{
|
||
|
|
m_List[i1] = m_List[i2];
|
||
|
|
}
|
||
|
|
m_iLast = i1; // i1 = m_iLast-1
|
||
|
|
return TRUE;
|
||
|
|
}
|
||
|
|
|
||
|
|
}
|
||
|
|
|
||
|
|
// return the number of elements in the queue
|
||
|
|
UINT GetCount(void)
|
||
|
|
{
|
||
|
|
return (m_iLast >= m_iFirst ? m_iLast-m_iFirst : m_iLast+m_maxItems-m_iFirst);
|
||
|
|
}
|
||
|
|
~QueueOf()
|
||
|
|
{
|
||
|
|
delete []m_List;
|
||
|
|
}
|
||
|
|
private:
|
||
|
|
BOOL Grow(void)
|
||
|
|
{
|
||
|
|
int i,j;
|
||
|
|
// double the size of the queue array
|
||
|
|
T* pNewList = new T [m_maxItems*2];
|
||
|
|
if (!pNewList)
|
||
|
|
return FALSE;
|
||
|
|
for (i=0, j=m_iFirst; j != m_iLast; i++, j = ((++j)&(m_maxItems-1)))
|
||
|
|
{
|
||
|
|
pNewList[i] = m_List[j];
|
||
|
|
}
|
||
|
|
m_iFirst = 0;
|
||
|
|
m_iLast = i;
|
||
|
|
m_maxItems = m_maxItems*2;
|
||
|
|
delete [] m_List;
|
||
|
|
m_List = pNewList;
|
||
|
|
return TRUE;
|
||
|
|
}
|
||
|
|
int m_maxItems;
|
||
|
|
int m_iFirst;
|
||
|
|
int m_iLast;
|
||
|
|
T *m_List;
|
||
|
|
};
|
||
|
|
;
|
||
|
|
#endif
|