Help me to understand the code please!

//*
//* my_DailyOpen_indicator
//*
//* Revision 1.1  2005/11/13 Midnite
//* Initial DailyOpen indicator
//* based pm  
//*
#property copyright "Midnite"
#property link      "[email protected]"

#property indicator_chart_window
#property indicator_buffers 1
#property indicator_color1 DodgerBlue
#property indicator_style1 2
#property indicator_width1 1

double TodayOpenBuffer[];
extern int TimeZoneOfData= 0;
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int init()
{
SetIndexStyle(0,DRAW_LINE);
SetIndexBuffer(0,TodayOpenBuffer);
SetIndexLabel(0,"Open");
SetIndexEmptyValue(0,0.0);
return(0);
}
//+------------------------------------------------------------------+
//| Custor indicator deinitialization function                       |
//+------------------------------------------------------------------+
int deinit()
{
return(0);
}
//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
int start()
{
   int lastbar;
   int counted_bars= IndicatorCounted();
   
   if (counted_bars>0) counted_bars--;
   lastbar = Bars-counted_bars;
   DailyOpen(0,lastbar);
   
   return (0);
}
//+------------------------------------------------------------------+
//|                                                                  |
//+------------------------------------------------------------------+
int DailyOpen(int offset, int lastbar)
{
   int shift;
   int tzdiffsec= TimeZoneOfData * 3600;
   double barsper30= 1.0*PERIOD_M30/Period();//<<<<<<<<<<<<<<<<-----------thise line no clear to me-------
   bool ShowDailyOpenLevel= True;
   // lastbar+= barsperday+2;  // make sure we catch the daily open 
   lastbar= MathMin(Bars-20*barsper30-1, lastbar);//<<<<<<<<<<-------thise also not clear-------

for(shift=lastbar;shift>=offset;shift--){
  TodayOpenBuffer[shift]= 0;
     if (ShowDailyOpenLevel){
       if(TimeDay(Time[shift]-tzdiffsec) != TimeDay(Time[shift+1]-tzdiffsec)){      // day change
         TodayOpenBuffer[shift]= Open[shift];         
         TodayOpenBuffer[shift+1]= 0;                                                           // avoid stairs in the line
       }
       else{
         TodayOpenBuffer[shift]= TodayOpenBuffer[shift+1];
       }
  }
   }
   return(0);
}

//+------------------------------------------------------------------+
//|                                            Daily-Weekly Open.mq4 |
//|                                           [email protected] |
//|      http://www.learncurrencytrading.com/fxforum/blogs/djindyfx/ |
//+------------------------------------------------------------------+
#property copyright "[email protected]"
#property link      "http://www.learncurrencytrading.com/fxforum/blogs/djindyfx/"

#property indicator_chart_window
#property indicator_buffers 2
#property indicator_color1 Aqua
#property indicator_color2 Red
//---- buffers
double dailyopen[];
double weeklyopen[];
double line;
double d,w;

//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int init()
  {
//---- indicators
   SetIndexStyle(0,DRAW_LINE,STYLE_DOT,1);
   SetIndexBuffer(0,dailyopen);
   SetIndexStyle(1,DRAW_LINE,STYLE_DASHDOT,1);
   SetIndexBuffer(1,weeklyopen);
   
   string dopen, wopen;
   dopen = "Daily Open";
   wopen = "Weekly Open";
   
   IndicatorShortName(dopen);
   IndicatorShortName(wopen);
   
   SetIndexLabel(0,dopen);
   SetIndexLabel(1,wopen);
   
   SetIndexDrawBegin(0,1);
   //SetIndexDrawBegin(1,1);
   
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| Custom indicator deinitialization function                       |
//+------------------------------------------------------------------+
int deinit()
  {
//----
   //ObjectDelete("Weekly Open");
   //ObjectDelete("Daily Open");
   
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
int start()
  {
   int counted_bars=IndicatorCounted();
   int limit, i;
   
//----
   if(counted_bars==0)
      {//0
       //d=Period();
       //if (d>240)return(-1);
       ObjectCreate("Weekly Open",OBJ_HLINE,0,0,0);
       ObjectCreate("Daily Open",OBJ_HLINE,0,0,0);
      }//0
   
  
   if(counted_bars<0) return(-1);
   
   limit=(Bars-counted_bars)-1;
   
   for(i=limit; i>=0; i--)
      {//0
       if(1==TimeDayOfWeek(Time[i]) && 1!=TimeDayOfWeek(Time[i+1]))
         {//1
          w=Open[i];
          ObjectMove("Weekly Open",0,Time[i],line);
         }//2
       if (TimeDay(Time[i]) !=TimeDay(Time[i+1]))
         {//3
          d=Open[i];
          ObjectMove("Daily Open",0,Time[i],line);
         }//3
       weeklyopen[i]=w;
       dailyopen[i]=d;
      }//0
   
//----
   return(0);
  }
//+------------------------------------------------------------------+

Quoting lukeb

Disliked

I had some questions about what IndicatorCounted() was doing and wrote an indicator that has the sole purpose of showing what IndicatorCounted() returns. It is here: http://forum.mql4.com/47935.

I'm thinking of changing from using IndicatorCounted() to using the Time[] array and keeping the last processed in a static datetime variable to determine how far back to calculate.

Ignored