/* ECP: FILEname=fig10_18.c */
/* 1*/   /* After Queue Is Doubled, Arrangement May Be Bad. */
/* 2*/   /* This Routine Fixes It, And Avoids Excessive Moves */

/* 3*/   static void
/* 4*/   FixWraparound( Queue Q )
/* 5*/   {
/* 6*/       const int OrigSz = Q->MaxSize / 2;

/* 7*/       if( Q->Front < OrigSz / 2  )
/* 8*/       {
/* 9*/           memcpy( &Q->Array[ OrigSz ], &Q->Array[ 0 ],
/*10*/                   Q->Front * sizeof( QuEtype ) );
/*11*/           Q->Back += OrigSz;
/*12*/       } 
/*13*/       else
/*14*/       {
/*15*/           memcpy( &Q->Array[  OrigSz + Q->Front ],
/*16*/                   &Q->Array[ Q->Front ],
/*17*/                   ( OrigSz - Q->Front ) * sizeof( QuEtype ) );
/*18*/           Q->Front += OrigSz;
/*19*/       }
/*20*/   }
/*21*/               

/* 1*/   void
/* 2*/   Enqueue( QuEtype X, Queue Q )
/* 3*/   {
/* 4*/       QuInsistGood( Q );
/* 5*/       if( Q->Size == Q->MaxSize )
/* 6*/       {
/* 7*/           Q->MaxSize *= 2;
/* 8*/           Q->Array = realloc( Q->Array,
/* 9*/                   sizeof( QuEtype ) * Q->MaxSize );
/*10*/           if( Q->Array == NULL )
/*11*/           {
/*12*/               printf( "Can not extend the queue\n" );
/*13*/               exit( -1 );
/*14*/           }
/*15*/           if( Q->Front != 0 )
/*16*/               FixWraparound( Q );
/*17*/       }
/*18*/       Q->Back = Increment( Q->Back, Q->MaxSize );
/*19*/       Q->Array[ Q->Back ] = X;
/*20*/       Q->Size++;
/*21*/   }