TextSegment.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Framework / System / Windows / Documents / TextSegment.cs / 1305600 / TextSegment.cs
                        

                        
                            //---------------------------------------------------------------------------- 
//
// File: TextSegment.cs
//
// Copyright (C) Microsoft Corporation.  All rights reserved. 
//
// Description: A pair of TextPositions used to denote a run of TextContainer content. 
// 
//---------------------------------------------------------------------------
 
namespace System.Windows.Documents
{
    using MS.Internal;
    using System.Collections; 

    ///  
    /// A pair of TextPositions used to denote a run of TextContainer content. 
    /// 
    // 

    internal struct TextSegment
    {
        //----------------------------------------------------- 
        //
        //  Constructors 
        // 
        //-----------------------------------------------------
 
        #region Constructors

        /// 
        /// Constructor. 
        /// 
        ///  
        /// Position preceeding the TextSegment's content. 
        /// 
        ///  
        /// Position following the TextSegment's content.
        /// 
        /// 
        /// If startPosition or endPosition are TextNavigators (derived from 
        /// TextPointer), the TextSegment constructor will store new TextPointer
        /// instances internally.  The values returned by the Start and End 
        /// properties are always immutable TextPositions. 
        /// 
        internal TextSegment(ITextPointer startPosition, ITextPointer endPosition) : 
            this(startPosition, endPosition, false)
        {
        }
 
        /// 
        /// Constructor. 
        ///  
        /// 
        /// Position preceeding the TextSegment's content. 
        /// 
        /// 
        /// Position following the TextSegment's content.
        ///  
        /// 
        /// Whether preserves LogicalDirection of start and end positions. 
        ///  
        internal TextSegment(ITextPointer startPosition, ITextPointer endPosition, bool preserveLogicalDirection)
        { 
            ValidationHelper.VerifyPositionPair(startPosition, endPosition);

            if (startPosition.CompareTo(endPosition) == 0)
            { 
                // To preserve segment emptiness
                // we use the same instance of a pointer 
                // for both segment ends. 
                _start = startPosition.GetFrozenPointer(startPosition.LogicalDirection);
                _end = _start; 
            }
            else
            {
                Invariant.Assert(startPosition.CompareTo(endPosition) < 0); 
                _start = startPosition.GetFrozenPointer(preserveLogicalDirection ? startPosition.LogicalDirection : LogicalDirection.Backward);
                _end = endPosition.GetFrozenPointer(preserveLogicalDirection ? endPosition.LogicalDirection : LogicalDirection.Forward); 
            } 
        }
 
        #endregion Constructors

        //------------------------------------------------------
        // 
        //  Internal Methods
        // 
        //----------------------------------------------------- 

        #region Internal Methods 

        /// 
        /// returns true if the segment contains a given position
        ///  
        //
        internal bool Contains(ITextPointer position) 
        { 
            return (!this.IsNull && this._start.CompareTo(position) <= 0 && position.CompareTo(this._end) <= 0);
        } 

        #endregion Internal Methods

        //------------------------------------------------------ 
        //
        //  Internal Properties 
        // 
        //------------------------------------------------------
 
        #region Internal Properties

        /// 
        /// Position preceeding the TextSegment's content. 
        /// 
        internal ITextPointer Start 
        { 
            get
            { 
                return _start;
            }
        }
 
        /// 
        /// Position following the TextSegment's content. 
        ///  
        internal ITextPointer End
        { 
            get
            {
                return _end;
            } 
        }
 
        internal bool IsNull 
        {
            get 
            {
                return _start == null || _end == null;
            }
        } 

        #endregion Internal Properties 
 
        /// 
        /// The "TextSegment.Null" value. 
        /// 
        /// 
        /// TextSegtemt.Null is used in contexts where text segment is missing.
        ///  
        internal static readonly TextSegment Null = new TextSegment();
 
        //----------------------------------------------------- 
        //
        //  Private Fields 
        //
        //------------------------------------------------------

        #region Private Fields 

        // Position preceeding the TextSegment's content. 
        private readonly ITextPointer _start; 

        // Position following the TextSegment's content. 
        private readonly ITextPointer _end;

        #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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