コード例 #1
0
ファイル: PhpArray.cs プロジェクト: dw4dev/Phalanger
		/// <summary>
		/// Compares two instances of <see cref="PhpArray"/>.
		/// </summary>
		/// <param name="comparer">The comparer.</param>
		/// <param name="incomparable">Whether arrays are incomparable 
		/// (no difference is found before both arrays enters an infinite recursion). 
		/// Returns zero then.</param>
		/// <include file='Doc/Common.xml' path='docs/method[@name="Compare(x,y)"]/*'/>
		private static int CompareArrays(PhpArray x, PhpArray y, IComparer comparer, out bool incomparable)
		{
			Debug.Assert(x != null && y != null);

			incomparable = false;

            // if both operands point to the same internal dictionary:
            if (object.ReferenceEquals(x.table, y.table))
                return 0;

            //
			object child_x, child_y;
			PhpArray array_x, array_y;
			PhpArray sorted_x, sorted_y;
			IEnumerator<KeyValuePair<IntStringKey, object>> iter_x, iter_y;

			// if numbers of elements differs:
			int result = x.Count - y.Count;
			if (result != 0) return result;

			// comparing with the same instance:
			if (x == y) return 0;

			// marks arrays as visited (will be always restored to false value before return):
			x.Visited = true;
			y.Visited = true;

			// it will be more effective to implement OrderedHashtable.ToOrderedList method and use it here (in future version):
			sorted_x = (PhpArray)x.Clone();
			sorted_x.Sort(KeyComparer.ArrayKeys);
			sorted_y = (PhpArray)y.Clone();
			sorted_y.Sort(KeyComparer.ArrayKeys);

			iter_x = sorted_x.GetEnumerator();
			iter_y = sorted_y.GetEnumerator();

			result = 0;

			try
			{
				// compares corresponding elements (keys first values then):
				while (iter_x.MoveNext())
				{
					iter_y.MoveNext();

					// compares keys:
					result = iter_x.Current.Key.CompareTo(iter_y.Current.Key);
					if (result != 0) break;

					// dereferences childs if they are references:
					child_x = PhpVariable.Dereference(iter_x.Current.Value);
					child_y = PhpVariable.Dereference(iter_y.Current.Value);

					// compares values:
					if ((array_x = child_x as PhpArray) != null)
					{
						if ((array_y = child_y as PhpArray) != null)
						{
							// at least one child has not been visited yet => continue with recursion:
							if (!array_x.Visited || !array_y.Visited)
							{
								result = CompareArrays(array_x, array_y, comparer, out incomparable);
							}
							else
							{
								incomparable = true;
							}

							// infinity recursion has been detected:
							if (incomparable) break;
						}
						else
						{
							// compares an array with a non-array:
                            array_x.CompareTo(child_y, comparer);
						}
					}
					else
					{
						// compares unknown item with a non-array:
						result = -comparer.Compare(child_y, child_x);
					}

					if (result != 0) break;
				} // while
			}
			finally
			{
				x.Visited = false;
				y.Visited = false;
			}
			return result;
		}