/***********************************************************************************[BoundedQueue.h]
 Glucose -- Copyright (c) 2009, Gilles Audemard, Laurent Simon
                CRIL - Univ. Artois, France
                LRI  - Univ. Paris Sud, France
 
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associated documentation files (the "Software"), to deal in the Software without restriction,
including without limitation the rights to use, copy, modify, merge, publish, distribute,
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The above copyright notice and this permission notice shall be included in all copies or
substantial portions of the Software.
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
**************************************************************************************************/


#ifndef BoundedQueue_h
#define BoundedQueue_h

#include "mtl/Vec.h"

//=================================================================================================

namespace Glucose {

template <class T>
class bqueue {
    vec<T>  elems;
    int     first;
	int		last;
	unsigned long long sumofqueue;
	int     maxsize;
	int     queuesize; // Number of current elements (must be < maxsize !)
	bool expComputed;
	double exp,value;
public:
 bqueue(void) : first(0), last(0), sumofqueue(0), maxsize(0), queuesize(0),expComputed(false) { } 
	
	void initSize(int size) {growTo(size);exp = 2.0/(size+1);} // Init size of bounded size queue
	
	void push(T x) {
	  expComputed = false;
		if (queuesize==maxsize) {
			assert(last==first); // The queue is full, next value to enter will replace oldest one
			sumofqueue -= elems[last];
			if ((++last) == maxsize) last = 0;
		} else 
			queuesize++;
		sumofqueue += x;
		elems[first] = x;
		if ((++first) == maxsize) {first = 0;last = 0;}
	}

	T peek() { assert(queuesize>0); return elems[last]; }
	void pop() {sumofqueue-=elems[last]; queuesize--; if ((++last) == maxsize) last = 0;}
	
	unsigned long long getsum() const {return sumofqueue;}
	unsigned int getavg() const {return (unsigned int)(sumofqueue/((unsigned long long)queuesize));}
	int maxSize() const {return maxsize;}
	double getavgDouble() const {
	  double tmp = 0;
	  for(int i=0;i<elems.size();i++) {
	    tmp+=elems[i];
	  }
	  return tmp/elems.size();
	}
	int isvalid() const {return (queuesize==maxsize);}
	
	void growTo(int size) {
		elems.growTo(size); 
		first=0; maxsize=size; queuesize = 0;last = 0;
		for(int i=0;i<size;i++) elems[i]=0; 
	}
	
	double getAvgExp() {
	  if(expComputed) return value;
	  double a=exp;
	  value = elems[first];
	  for(int i  = first;i<maxsize;i++) {
	    value+=a*((double)elems[i]);
	    a=a*exp;
	  }
	  for(int i  = 0;i<last;i++) {
	    value+=a*((double)elems[i]);
	    a=a*exp;
	  }
	  value = value*(1-exp)/(1-a);
	  expComputed = true;
	  return value;
	  

	}
	void fastclear() {first = 0; last = 0; queuesize=0; sumofqueue=0;} // to be called after restarts... Discard the queue
	
    int  size(void)    { return queuesize; }

    void clear(bool dealloc = false)   { elems.clear(dealloc); first = 0; maxsize=0; queuesize=0;sumofqueue=0;}


};
}
//=================================================================================================

#endif