nifexpr.cpp

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Copyright (c) 2005-2012, NIF File Format Library and Tools
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#include "nifexpr.h"
#include "basemodel.h"

static bool matchGroup(const QString & cond, int offset, int& startpos, int& endpos)
{
   int scandepth = 0;
   startpos = -1;
   endpos = -1;
   for (int scanpos = offset, len=cond.length(); scanpos != len; ++scanpos) {
      QChar c = cond[scanpos];
      if (c == '(') {
         if (startpos == -1)
            startpos = scanpos;
         ++scandepth;
      } else if ( c == ')' ) {
         if (--scandepth == 0) {
            endpos = scanpos;
            return true;
         }
      }
   }
   if (startpos != -1 || endpos != -1)
      throw "expression syntax error (non-matching brackets?)";
   return false;
}


static quint32 version2number( const QString & s )
{
   if ( s.isEmpty() )	return 0;

   if ( s.contains( "." ) )
   {
      QStringList l = s.split( "." );

      quint32 v = 0;

      if ( l.count() > 4 ) {
         //Should probaby post a warning here or something.  Version # has more than 3 dots in it.
         return 0;
      } else if ( l.count() == 2 ) {
         //This is an old style version number.  Take each digit following the first one at a time.
         //The first one is the major version
         v += l[0].toInt() << (3 * 8);

         if ( l[1].size() >= 1 ) {
            v += l[1].mid(0, 1).toInt() << (2 * 8);
         }
         if ( l[1].size() >= 2 ) {
            v += l[1].mid(1, 1).toInt() << (1 * 8);
         }
         if ( l[1].size() >= 3 ) {
            v += l[1].mid(2, -1).toInt();
         }
         return v;
      } else {
         //This is a new style version number with dots separating the digits
         for ( int i = 0; i < 4 && i < l.count(); i++ ) {
            v += l[i].toInt( 0, 10 ) << ( (3-i) * 8 );
         }
         return v;
      }

   } else {
      bool ok;
      quint32 i = s.toUInt( &ok );
      return ( i == 0xffffffff ? 0 : i );
   }
}

Expression::Operator Expression::operatorFromString( const QString& str )
{
   if ( str == "!" ) return Expression::e_not;
   else if ( str == "!=" ) return Expression::e_not_eq;
   else if ( str == "==" ) return Expression::e_eq;
   else if ( str == ">=" ) return Expression::e_gte;
   else if ( str == "<=" ) return Expression::e_lte;
   else if ( str == ">" ) return Expression::e_gt;
   else if ( str == "<" ) return Expression::e_lt;
   else if ( str == "&" ) return Expression::e_bit_and;
   else if ( str == "|" ) return Expression::e_bit_or;
   else if ( str == "+" ) return Expression::e_add;
   else if ( str == "-" ) return Expression::e_sub;
   else if ( str == "&&" ) return Expression::e_bool_and;
   else if ( str == "||" ) return Expression::e_bool_or;
   return Expression::e_nop;
}

void Expression::partition( const QString & cond, int offset /*= 0*/ )
{
   int pos;
   if (cond.isEmpty())
   {
      this->opcode = Expression::e_nop;
      return;
   }

   // Handle unary operators
   QRegExp reUnary("^\\s*!(.*)");
   pos = reUnary.indexIn(cond, offset, QRegExp::CaretAtOffset);
   if (pos != -1) {
      Expression e(reUnary.cap(1).trimmed());
      this->opcode = Expression::e_not;
      this->rhs = QVariant::fromValue( e );
      return;
   }
   // Check for left group
   int lstartpos=-1, lendpos=-1, ostartpos=-1, oendpos=-1, rstartpos=-1, rendpos=-1;
   //QRegExp tokens("\b(!=|==|>=|<=|>|<|\\&|\+|-|\\&\\&|\\|\\||\(|\)|[a-zA-Z0-9][a-zA-Z0-9_ \\?]*[a-zA-Z0-9_\\?]?)\b");
   QRegExp reOps("(!=|==|>=|<=|>|<|\\&|\\||\\+|-|\\&\\&|\\|\\|)");
   QRegExp reLParen("^\\s*\\(.*");
   pos = reLParen.indexIn(cond,offset, QRegExp::CaretAtOffset);
   if (pos != -1) {
      matchGroup(cond, pos, lstartpos, lendpos);
      pos = reOps.indexIn(cond, lendpos+1, QRegExp::CaretAtOffset);
      ++lstartpos, --lendpos;
      if (pos != -1) {
         ostartpos = pos;
         oendpos = ostartpos + reOps.cap(0).length();
      } else {
         partition(cond.mid(lstartpos, lendpos-lstartpos+1));
         return;
      }
   } else {
      pos = reOps.indexIn(cond, offset, QRegExp::CaretAtOffset);
      if (pos != -1) {
         lstartpos = offset;
         lendpos = pos - 1;
         ostartpos = pos;
         oendpos = ostartpos + reOps.cap(0).length();
      } else {
         static QRegExp reInt("[-+]?[0-9]+");
         static QRegExp reUInt("0[xX][0-9]+");
         static QRegExp reFloat("^[-+]?[0-9]*\\.?[0-9]+([eE][-+]?[0-9]+)?$");
         static QRegExp reVersion("[0-9]+\\.[0-9]+\\.[0-9]+\\.[0-9]+");

         // termination
         this->lhs.setValue(cond);
         if (reUInt.exactMatch(cond)) {
            this->lhs.convert(QVariant::UInt);
         } else if (reInt.exactMatch(cond)) {
            this->lhs.convert(QVariant::Int);
         } else if (reVersion.exactMatch(cond)) {
            this->lhs.setValue( version2number(cond) );
         }
         this->opcode = Expression::e_nop;
         return;
      }
   }

   rstartpos = oendpos+1;
   rendpos = cond.size() - 1;

   Expression lhsexp(cond.mid(lstartpos, lendpos-lstartpos+1).trimmed());
   Expression rhsexp(cond.mid(rstartpos, rendpos-rstartpos+1).trimmed());
   if (lhsexp.opcode == Expression::e_nop) {
      this->lhs = lhsexp.lhs;
   } else {
      this->lhs = QVariant::fromValue( lhsexp );
   }
   this->opcode = operatorFromString(cond.mid(ostartpos, oendpos-ostartpos));
   if (rhsexp.opcode == Expression::e_nop) {
      this->rhs = rhsexp.lhs;
   } else {
      this->rhs = QVariant::fromValue( rhsexp );
   }
}

QString Expression::toString() const
{
   QString l = lhs.toString();
   QString r = rhs.toString();
   if (lhs.type() == QVariant::UserType && lhs.canConvert<Expression>())
      l = lhs.value<Expression>().toString();
   if (rhs.type() == QVariant::UserType && rhs.canConvert<Expression>())
      r = rhs.value<Expression>().toString();

   switch (opcode)
   {
   case Expression::e_not:
      return QString("!%1").arg(r);
   case Expression::e_not_eq:
      return QString("(%1 != %2)").arg(l).arg(r);
   case Expression::e_eq:
      return QString("(%1 == %2)").arg(l).arg(r);
   case Expression::e_gte:
      return QString("(%1 >= %2)").arg(l).arg(r);
   case Expression::e_lte:
      return QString("(%1 <= %2)").arg(l).arg(r);
   case Expression::e_gt:
      return QString("(%1 > %2)").arg(l).arg(r);
   case Expression::e_lt:
      return QString("(%1 < %2)").arg(l).arg(r);
   case Expression::e_bit_and:
      return QString("(%1 & %2)").arg(l).arg(r);
   case Expression::e_bit_or:
      return QString("(%1 | %2)").arg(l).arg(r);
   case Expression::e_add:
      return QString("(%1 + %2)").arg(l).arg(r);
   case Expression::e_sub:
      return QString("(%1 - %2)").arg(l).arg(r);
   case Expression::e_bool_and:
      return QString("(%1 && %2)").arg(l).arg(r);
   case Expression::e_bool_or:
      return QString("(%1 || %2)").arg(l).arg(r);
   case Expression::e_nop:
      return QString("%1").arg(l);
   }
   return QString();
}

void Expression::NormalizeVariants( QVariant &l, QVariant &r ) const
{
	if (l.isValid() && r.isValid()) {
		if (l.type() != r.type()) {
			if ( l.type() == QVariant::String && l.canConvert(r.type()) )
				l.convert(r.type());
			else if ( r.type() == QVariant::String && r.canConvert(l.type()) )
				r.convert(l.type());
			else
			{
				QVariant::Type t = l.type() > r.type() ? l.type() : r.type();
				if (r.canConvert(t) && l.canConvert(t)) {
					l.convert(t);
					r.convert(t);
				}
			}
		}
	}
}