Turtle Channel Method

//+------------------------------------------------------------------+
//|                              Turtle Channel Method(Donchain).mq4 |
//|                                           djindyFX@sbcglobal.net |
//|      http://www.learncurrencytrading.com/fxforum/blogs/djindyfx/ |
//+------------------------------------------------------------------+
#property copyright "djindyFX@yahoo.com"
#property link      "http://www.learncurrencytrading.com/fxforum/blogs/djindyfx/"
/* - Original Donchain channel code posted here: http://codebase.mql4.com/ru/1317
      Periods: number of bars used for calculating the Donchian channels
               3 Seperate Channels are provided, Long term, Medium, and Short Term
      Extremes: 1 uses the highest high and the lowest low to create the Channel
                0 uses the open of the extremes bar -> the open point of a bar (as well as the close
                   are the points of maximum probability of concentration of the prices during the bar
                3 uses the median point most extreme open and lowest low or highest high
      Margins: is the percent of the channel subtrated from the channel border before printing it, negative values are allowed
      Advance: the numbers of bars ahead
*/


#property indicator_chart_window
#property indicator_buffers 6
#property indicator_color1 White
#property indicator_color2 White
#property indicator_color3 Yellow
#property indicator_color4 Yellow
#property indicator_color5 Red
#property indicator_color6 Red

//---- input parameters
extern int       LngPeriod=50;
extern int       MedPeriod=20;
extern int       ShtPeriod=5;
extern int       Extremes=1;
extern int       Margins=0; 
extern int       Advance=0;
extern int       max_bars=1400;

// - Buffers
double Channel1[];
double Channel2[];
double Channel3[];
double Channel4[];
double Channel5[];
double Channel6[];

//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int init()
  {
  Comment("Turtle Channel is running");
  string LngTop, LngBottom, MedTop, MedBottom, ShtTop, ShtBottom;
  
//---- indicators
   SetIndexStyle(0,DRAW_LINE,STYLE_DOT);
   SetIndexStyle(1,DRAW_LINE,STYLE_DOT);
   SetIndexStyle(2,DRAW_LINE,STYLE_DASH);
   SetIndexStyle(3,DRAW_LINE,STYLE_DASH);
   SetIndexStyle(4,DRAW_LINE,STYLE_DASHDOT);
   SetIndexStyle(5,DRAW_LINE,STYLE_DASHDOT);
   
   SetIndexBuffer(0,Channel1);
   SetIndexBuffer(1,Channel2);
   SetIndexBuffer(2,Channel3);
   SetIndexBuffer(3,Channel4);
   SetIndexBuffer(4,Channel5);
   SetIndexBuffer(5,Channel6);
   
   LngTop = "Long Top";
   LngBottom = "Long Bottom";
   MedTop = "Medium Top";
   MedBottom = "Medium Bottom";
   ShtTop = "Short Top";
   ShtBottom = "Short Bottom";
   
   IndicatorShortName(LngTop);
   IndicatorShortName(LngBottom);
   IndicatorShortName(MedTop);
   IndicatorShortName(MedBottom);
   IndicatorShortName(ShtTop);
   IndicatorShortName(ShtBottom);
   
   SetIndexLabel(0,LngTop);
   SetIndexLabel(1,LngBottom);
   SetIndexLabel(2,MedTop);
   SetIndexLabel(3,MedBottom);
   SetIndexLabel(4,ShtTop);
   SetIndexLabel(5,ShtBottom);

//----
   return(0);
  }
//+------------------------------------------------------------------+
//| Custom indicator deinitialization function                       |
//+------------------------------------------------------------------+
int deinit()
  {
//----
   
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
int start()
  {
   int   counted_bars=IndicatorCounted();
   if    (counted_bars < 0) return(-1);
   if    (counted_bars>0) counted_bars--;
   
   double   sminl=0, smaxl=0, SsMinl=0, SsMaxl=0;
   double   sminm=0, smaxm=0, SsMinm=0, SsMaxm=0;
   double   smins=0, smaxs=0, SsMins=0, SsMaxs=0;

//----

   for(int shift = 0; shift< max_bars; shift++)
   {
      if(Extremes ==1)
      {
         SsMaxl = High[iHighest(NULL,0,MODE_HIGH,LngPeriod,shift)];
         SsMinl = Low[iLowest(NULL,0,MODE_LOW,LngPeriod,shift)];
         SsMaxm = High[iHighest(NULL,0,MODE_HIGH,MedPeriod,shift)];
         SsMinm = Low[iLowest(NULL,0,MODE_LOW,MedPeriod,shift)];
         SsMaxs = High[iHighest(NULL,0,MODE_HIGH,ShtPeriod,shift)];
         SsMins = Low[iLowest(NULL,0,MODE_LOW,ShtPeriod,shift)];
      }
      else if (Extremes ==3)
      {
         SsMaxl = (Open[iHighest(NULL,0,MODE_OPEN,LngPeriod,shift)]+High[iHighest(NULL,0,MODE_HIGH,LngPeriod,shift)])/2;
         SsMinl = (Open[iLowest(NULL,0,MODE_OPEN,LngPeriod,shift)]+Low[iLowest(NULL,0,MODE_LOW,LngPeriod,shift)])/2;
         SsMaxm = (Open[iHighest(NULL,0,MODE_OPEN,MedPeriod,shift)]+High[iHighest(NULL,0,MODE_HIGH,MedPeriod,shift)])/2;
         SsMinm = (Open[iLowest(NULL,0,MODE_OPEN,MedPeriod,shift)]+Low[iLowest(NULL,0,MODE_LOW,MedPeriod,shift)])/2;
         SsMaxs = (Open[iHighest(NULL,0,MODE_OPEN,ShtPeriod,shift)]+High[iHighest(NULL,0,MODE_HIGH,ShtPeriod,shift)])/2;
         SsMins = (Open[iLowest(NULL,0,MODE_OPEN,ShtPeriod,shift)]+Low[iLowest(NULL,0,MODE_LOW,ShtPeriod,shift)])/2;
      }
      else
      {
         SsMaxl = Open[iHighest(NULL,0,MODE_OPEN,LngPeriod,shift)];
         SsMinl = Open[iLowest(NULL,0,MODE_OPEN,LngPeriod,shift)];
         SsMaxm = Open[iHighest(NULL,0,MODE_OPEN,MedPeriod,shift)];
         SsMinm = Open[iLowest(NULL,0,MODE_OPEN,MedPeriod,shift)];
         SsMaxs = Open[iHighest(NULL,0,MODE_OPEN,ShtPeriod,shift)];
         SsMins = Open[iLowest(NULL,0,MODE_OPEN,ShtPeriod,shift)];
      }

     smaxl = SsMaxl-(SsMaxl-SsMinl)*Margins/100;
     sminl = SsMinl+(SsMaxl-SsMinl)*Margins/100;
     smaxm = SsMaxm-(SsMaxm-SsMinm)*Margins/100;
     sminm = SsMinm+(SsMaxm-SsMinm)*Margins/100;
     smaxs = SsMaxs-(SsMaxs-SsMins)*Margins/100;
     smins = SsMins+(SsMaxs-SsMins)*Margins/100;
     
     Channel1[shift-Advance]=smaxl;
     Channel2[shift-Advance]=sminl;
     Channel3[shift-Advance]=smaxm;
     Channel4[shift-Advance]=sminm;
     Channel5[shift-Advance]=smaxs;
     Channel6[shift-Advance]=smins;
   }

   
//----
   return(0);
  }
//+------------------------------------------------------------------+