コード例 #1
0
        public ComparerBuilder <TItem> Compare <TField>(Func <TItem, TField> expression, IComparer <TField> comparer, OrderFlavour flavour = OrderFlavour.Default)
        {
            if (expression == null)
            {
                throw new ArgumentNullException("expression");
            }

            if (comparer == null)
            {
                throw new ArgumentNullException("comparer");
            }

            Func <object, object, int> fieldComparison = delegate(object x, object y)
            {
                var  f             = flavour; // stack is faster then heap
                bool areNullsEarly = (f & OrderFlavour.NullGoesEarly) != 0;
                bool isBackward    = (f & OrderFlavour.Backward) != 0;

                // 1. x & y are unconditionally NOT NULL and type of them is defenitely TItem
                // 2. The compiler replaces null comparisons with a call to HasValue for nullable types
                TField xField = expression((TItem)x);
                TField yField = expression((TItem)y);
                if (TypeInfo <TField> .IsReferenceType && ReferenceEquals(xField, yField))
                {
                    return(0);
                }
                if (xField == null && yField == null)
                {
                    return(0);
                }
                if (xField == null)
                {
                    return(areNullsEarly ? -1 : 1);
                }
                if (yField == null)
                {
                    return(areNullsEarly ? 1 : -1);
                }
                int ret = comparer.Compare(xField, yField);
                return(isBackward ? -ret : ret);
            };

            _Comparisons.Add(new FieldMeta()
            {
                Comparison = fieldComparison,
            });

            return(this);
        }
コード例 #2
0
 public Comparison <TItem> GetComparison(OrderFlavour flavour = OrderFlavour.Default)
 {
     // ThreadSafe
     return(new ItemComparer <TItem>(_Comparisons, OrderFlavour.Default).Compare);
 }
コード例 #3
0
 public IComparer <TItem> GetComparer(OrderFlavour flavour = OrderFlavour.Default)
 {
     return(new ItemComparer <TItem>(_Comparisons, flavour));
 }
コード例 #4
0
 public ComparerBuilder <TItem> CompareString(Func <TItem, string> expression, StringComparer comparer, OrderFlavour flavour = OrderFlavour.Default)
 {
     return(Compare(expression, comparer, flavour));
 }
コード例 #5
0
 public ComparerBuilder <TItem> Compare <TField>(Func <TItem, TField> expression, OrderFlavour flavour = OrderFlavour.Default)
 {
     return(Compare(expression, Comparer <TField> .Default, flavour));
 }
コード例 #6
0
 public ItemComparer(List <FieldMeta> fields, OrderFlavour orderFlavour)
 {
     _Fields       = fields;
     _OrderFlavour = orderFlavour;
 }