FlowNode.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Framework / System / Windows / Documents / FlowNode.cs / 1305600 / FlowNode.cs
                        
                        
                            //---------------------------------------------------------------------------- 
// 
//      Copyright (C) 2003 by Microsoft Corporation.  All rights reserved.
// 
// 
// Description:
//      FlowNode represents a structural node for a flow document. They 
//      are inserted into a content flow backing store content flow their 
//      relative orders signal the content flow order.
// 
// History:
//      11/03/2003 - Zhenbin Xu (ZhenbinX) - Created.
//
//--------------------------------------------------------------------------- 

namespace System.Windows.Documents 
{ 
    using System;
    using System.Diagnostics; 

    //=====================================================================
    /// 
    /// FlowNode represents a structural node in the Flow Order of a fixed document. 
    /// They are inserted into a content flow backing store (the Flow Order) to
    /// represent a flow order view of the fixed document.  Their relative position 
    /// in the Flow Order indicates their relative reading order. 
    ///
    /// A FlowNode is identified by its ScopeId and is compared by its relative position 
    /// in the Flow Order (Fp).
    ///
    /// Content structure and scope can be deduced from the Flow Order.
    /// For instance 
    ///     S1 S2 R2 E2 E1
    /// would indicate element 1 (S1-E1) is the parent of element 2 (S1-E2) 
    ///  
    internal sealed class FlowNode : IComparable
    { 
        //-------------------------------------------------------------------
        //
        // Connstructors
        // 
        //----------------------------------------------------------------------
 
        #region Constructors 
        internal FlowNode(int scopeId, FlowNodeType type, object cookie)
        { 
            //
            // If cookie is FixedElement, you have to set it later, otherwise,
            // please set it here.
            // In that case, cookie will be set as a FixedElement later. 
            // It cann't be set here because of the circular reference.
            // 
 
            //
            // We don't allow to create a glyph node with zero run length. 
            // it will lots of problem in textOM due to some assumption there.
            //
            Debug.Assert( (type != FlowNodeType.Run)  ||  ((int)cookie != 0));
 
            _scopeId = scopeId;
            _type       = type; 
            _cookie     = cookie; 
        }
        #endregion Constructors 

        //-------------------------------------------------------------------
        //
        // Public Methods 
        //
        //---------------------------------------------------------------------- 
 
        #region Public Methods
 
        // force object comparision
        public static bool IsNull(FlowNode flow)
        {
            return (object)flow == null; 
        }
 
 
        /// 
        ///  
        /// int - hash code
        public override int GetHashCode()
        {
            return _scopeId.GetHashCode()^_fp.GetHashCode(); 
        }
 
 
        /// 
        /// Compares this FlowNode with the passed in object 
        /// 
        /// The object to compare to "this"
        /// bool - true if the FlowNodes are equal, false otherwise
        public override bool Equals(object o) 
        {
            if (o == null || this.GetType() != o.GetType()) 
            { 
                return false;
            } 

            FlowNode fn = (FlowNode)o;
            Debug.Assert(_fp != fn._fp || (_fp == fn._fp) && (_scopeId == fn._scopeId));
 
            return (this._fp == fn._fp);
        } 
 

        ///  
        /// Compare the flow order of this FlowNode to another FlowNode
        /// 
        /// FlowNode to compare to
        /// -1, 0, 1 
        public int CompareTo(object o)
        { 
            if (o == null) 
            {
                throw new ArgumentNullException("o"); 
            }

            FlowNode fp = o as FlowNode;
            if (fp == null) 
            {
                throw new ArgumentException(SR.Get(SRID.UnexpectedParameterType, o.GetType(), typeof(FlowNode)), "o"); 
            } 

            if (Object.ReferenceEquals(this, fp)) 
            {
                return 0;
            }
 
            int fd = this._fp - fp._fp;
            if (fd == 0) 
            { 
                return 0;
            } 
            else if (fd < 0)
            {
                return -1;
            } 
            else
            { 
                return 1; 
            }
        } 

#if DEBUG
        /// 
        /// Create a string representation of this object 
        /// 
        /// string - A string representation of this object 
        public override string ToString() 
        {
            int page = -1; 

            switch (_type)
            {
                case FlowNodeType.Boundary: 
                case FlowNodeType.Start:
                case FlowNodeType.End: 
                case FlowNodeType.Object: 
                {
                    FixedElement element = _cookie as FixedElement; 
                    if (element != null)
                    {
                        page = element.PageIndex;
                    } 
                    break;
                } 
                case FlowNodeType.Virtual: 
                case FlowNodeType.Noop:
                { 
                    page = (int) _cookie;
                    break;
                }
                case FlowNodeType.Run: 
                {
                    if (this.FixedSOMElements != null && this.FixedSOMElements.Length > 0) 
                    { 
                        page = this.FixedSOMElements[0].FixedNode.Page;
                    } 
                    break;
                }
                default:
                    break; 
            }
 
 
            return String.Format("Pg{0}-nCp{1}-Id{2}-Tp{3}", page, _fp, _scopeId, System.Enum.GetName(typeof(FlowNodeType), _type));
        } 
#endif
        #endregion Public Methods

        //-------------------------------------------------------------------- 
        //
        // Public Properties 
        // 
        //---------------------------------------------------------------------
 
        //--------------------------------------------------------------------
        //
        // Public Events
        // 
        //---------------------------------------------------------------------
 
        //------------------------------------------------------------------- 
        //
        // Internal Methods 
        //
        //---------------------------------------------------------------------

        #region Internal Methods 

        // 
        // Note: Make these explicit method so that it won't be used mistakenly 
        // Only FixedTextBuilder can modify Fp
        // 

        internal void SetFp(int fp)
        {
            _fp = fp; 
        }
 
        internal void IncreaseFp() 
        {
            _fp++; 
        }

        internal void DecreaseFp()
        { 
            _fp--;
        } 
        #endregion Internal Methods 

        //-------------------------------------------------------------------- 
        //
        // Internal Properties
        //
        //--------------------------------------------------------------------- 

        #region Internal Properties 
        // Get/Set position within flow order 
        internal int Fp
        { 
            get
            {
                return _fp;
            } 
        }
 
        // Get the scope to which this node belongs 
        internal int ScopeId
        { 
            get
            {
                return _scopeId;
            } 
        }
 
        // Get the Flag associated with this node 
        internal FlowNodeType Type
        { 
            get
            {
                return _type;
            } 
        }
 
 
        // Get/Set the cookie associated with this position.
        // Higher level protocol decides what to put inside 
        // the cookie
        internal object Cookie
        {
            get 
            {
                return _cookie; 
            } 
        }
 
        internal FixedSOMElement[] FixedSOMElements
        {
            get
            { 
                return _elements;
            } 
            set 
            {
                _elements = value; 
            }
        }

        internal void AttachElement(FixedElement fixedElement) 
        {
            _cookie = fixedElement; 
        } 

        #endregion Internal Properties 


        //--------------------------------------------------------------------
        // 
        // Private Fields
        // 
        //---------------------------------------------------------------------- 

        #region Private Fields 
        private readonly int _scopeId;          // Node Identifier
        private readonly FlowNodeType _type;    // type of the node
        private int _fp;                        // Position in flow
        private object _cookie;                 // Associated object 
        private FixedSOMElement[] _elements;    // Used for mapping between fixed and flow representations
        #endregion Private Fields 
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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FlowNode.cs source code in C# .NET

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