130bool ValidPositive(const double value) {131   return MathIsValidNumber(value) && value>0.0;132}133bool ValidNonnegative(const double value) {134   return MathIsValidNumber(value) && value>=0.0;135}136bool MarginAndSpreadCost(const ENUM_ORDER_TYPE side,const string symbol,const double volume,137const double entry,double &cost)138{139   cost=0.0;140   if((side!=ORDER_TYPE_BUY && side!=ORDER_TYPE_SELL) || symbol=="" || !ValidPositive(volume) || !ValidPositive(entry)) return false;141   MqlTick quote;142   if(!SymbolInfoTick(symbol,quote) || !ValidPositive(quote.bid) || !MathIsValidNumber(quote.ask) || quote.ask<quote.bid) return false;143   double spread=quote.ask-quote.bid;144   const double exit_price=entry+(side==ORDER_TYPE_BUY ? -spread : spread);145   double margin=0.0,profit=0.0;146   if(exit_price<=0.0 || !OrderCalcMargin(side,symbol,volume,entry,margin) || !ValidNonnegative(margin)) return false;147   if(!OrderCalcProfit(side,symbol,volume,entry,exit_price,profit) || !MathIsValidNumber(profit)) return false;148   cost=margin+MathMax(0.0,-profit);149   return ValidNonnegative(cost);150}151bool PendingMarginReserve(double &reserve)152{153   reserve=0.0;154   for(int i=OrdersTotal()-1;i>=0;--i)155   {156      if(OrderGetTicket(i)==0) return false;157      const ENUM_ORDER_TYPE type=(ENUM_ORDER_TYPE)OrderGetInteger(ORDER_TYPE);158      if(type<ORDER_TYPE_BUY_LIMIT || type>ORDER_TYPE_SELL_STOP_LIMIT) continue;159      const double volume=OrderGetDouble(ORDER_VOLUME_CURRENT);160      if(!ValidNonnegative(volume)) return false;161      if(volume==0.0) continue;162      const string symbol=OrderGetString(ORDER_SYMBOL);163      const double entry=OrderGetDouble(type==ORDER_TYPE_BUY_STOP_LIMIT || type==ORDER_TYPE_SELL_STOP_LIMIT ? ORDER_PRICE_STOPLIMIT : ORDER_PRICE_OPEN);164      const ENUM_ORDER_TYPE side=(type==ORDER_TYPE_BUY_LIMIT || type==ORDER_TYPE_BUY_STOP || type==ORDER_TYPE_BUY_STOP_LIMIT ? ORDER_TYPE_BUY : ORDER_TYPE_SELL);165      double cost=0.0;166      if(!MarginAndSpreadCost(side,symbol,volume,entry,cost)) return false;167      reserve+=cost;168      if(!MathIsValidNumber(reserve)) return false;169   }170   return true;171}172bool FitsDirectionalVolumeLimit(const string symbol,const bool buy,const double volume,const double step)173{174   // The limit counts every strategy's same-symbol exposure in this direction.175   const double limit=SymbolInfoDouble(symbol,SYMBOL_VOLUME_LIMIT);176   if(!ValidNonnegative(limit)) return false;177   if(limit==0.0) return true;178   double used=0.0;179   for(int i=PositionsTotal()-1;i>=0;--i)