#property copyright "Copyright S.Projects"
#property link      "http://trader.snowseed.com"

#property indicator_separate_window
#property indicator_buffers 1
#property indicator_color1 Red
#property indicator_minimum 0
#property indicator_maximum 1

// indicator parameters
extern int nClvPeriod = 27;
extern int nClvMa = 7;

// At the very beginning of the chart, before the MA 
// had enough data to draw itself properly, do not display

int nDrawBeginBar;

// indicator buffers
double arrExtMapBuffer[];

// We are using this variable to store the number of bars
// for which the chart is already drawn. The difference
// between the total number of bars and this number is
// the number of bars to draw (usually, 1)

int nExtCountedBars = 0;

////////////////////////
int init()
{
	string strIndicatorShortName;
	strIndicatorShortName = "CLV(" + nClvPeriod + 
		", " + nClvMa + ")";  
	IndicatorShortName(strIndicatorShortName);

	// drawing settings
	SetIndexStyle(0, DRAW_LINE);
	SetIndexShift(0, 0);
		
	IndicatorDigits(4);
		
	// Skip drawing at the beginning of a chart
	nDrawBeginBar = MathMax(nClvPeriod, nClvMa);
	SetIndexDrawBegin(0, nDrawBeginBar);

	// indicator buffers mapping
	SetIndexBuffer(0, arrExtMapBuffer);
		
	return(0);
}
///////////////////////////
int start()
{
	// Not enough points on a chart
	if(Bars <= nDrawBeginBar) 
		return(0);
		
	// See if we have new data to plot (if a new tick came,
	// and it is the first tick of a new bar

	nExtCountedBars = IndicatorCounted();
	if(nExtCountedBars < 0) 
		return(-1);

	// Last counted bar will be recounted
	// Note, that here we force the last bar to be recounted.
	// You may comment this code, if you only want to do it
	// at the beginning of a new bar. I only keep this code
	// for compatibility with a little mess created by official
	// tutorials: see comment below (*)
	if(nExtCountedBars > 0) 
		nExtCountedBars--;
		
	Clv();  

	return(0);
}
///////////////////
// For the selected period:
// CLV = ((Close - Low) - (High - Close)) / (High - Low) 
void Clv()
{
	// (*) Note the line below. If we use 
	// "int nPos = Bars - nExtCountedBars;" the last bar 
	// will be recounted every tick. If there is no "- 1",
	// only the beginning of a new bar triggers the code. 

	int nPos = Bars - nExtCountedBars;

	// Note, that nPos is always > 0. It means, that Close[nPos]
	// is never Close[0], so we don't make a mistake by "looking
	// into the future". Note also, that we assign the value
	// to the arrExtMapBuffer[nPos]. It means, that when calling
	// this indicator from the expert, we need to use shift
	// >= 1. If we want to be able to call it with shift == 0,
	// we need to rewrite the code below, using 
	// arrExtMapBuffer[nPos - 1]. The Close[...] and all other
	// functions obtaining data, should still use [nPos].

	while(nPos > 0 && nPos < ArraySize(Low))
	{
		double dClose = Close[nPos];
		double dLow = Low[ArrayMinimum(Low, nClvPeriod, nPos)]; 
		double dHigh = High[ArrayMaximum(High, nClvPeriod, nPos)]; 

		arrExtMapBuffer[nPos] = 0;

		if(dHigh - dLow != 0)
			arrExtMapBuffer[nPos] = 
				(((dClose - dLow) - (dHigh - dClose)) 
					/ (dHigh - dLow)) / 2 + 0.5; 
		else
			arrExtMapBuffer[nPos] = 0;

		nPos--;
	}
	
	if(nClvMa > 1)
		Ema(arrExtMapBuffer);
}
///////////////////
void Ema(double& arr[])
{
	double dPr = 2.0 / (nClvMa + 1);

	int nPos = Bars - nExtCountedBars;
	
	while(nPos > 0)
	{
		if(nPos == Bars - 2) 
			arrExtMapBuffer[nPos + 1] = arr[nPos + 1];

		arrExtMapBuffer[nPos] = arr[nPos] * dPr + 
			arrExtMapBuffer[nPos + 1] * (1 - dPr);
		nPos--;
	}
}
///////////////////