Code:
/ DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Framework / System / Windows / Documents / RangeContentEnumerator.cs / 1 / RangeContentEnumerator.cs
#pragma warning disable 1634, 1691 // To enable presharp warning disables (#pragma suppress) below. //---------------------------------------------------------------------------- // //// Copyright (C) Microsoft Corporation. All rights reserved. // // // // Description: IEnumerator for TextRange and TextElement content. // // // History: // 05/27/2003 : [....] - Created // //--------------------------------------------------------------------------- using System; using System.Collections; using MS.Internal; using System.Text; using MS.Utility; using System.Windows.Controls; #pragma warning disable 1634, 1691 // suppressing PreSharp warnings namespace System.Windows.Documents { internal class RangeContentEnumerator : IEnumerator { //----------------------------------------------------- // // Constructors // //----------------------------------------------------- #region Constructors // Creates an enumerator instance. // Null start/end creates an empty enumerator. internal RangeContentEnumerator(TextPointer start, TextPointer end) { Invariant.Assert(start != null && end != null || start == null && end == null, "If start is null end should be null!"); _start = start; _end = end; // Remember what generation the backing store was in when we started, // so we can throw if this enumerator is accessed after content has // changed. if (_start != null) { _generation = _start.TextContainer.Generation; } } #endregion Constructors //------------------------------------------------------ // // Public Methods // //----------------------------------------------------- #region Public Methods ////// Return the current object this enumerator is pointing to. This is /// generally a FrameworkElement, TextElement, an embedded /// object, or Text content. /// public object Current { get { int runLength; int offset; if (_navigator == null) { // Disable presharp 6503: Property get methods should not throw exceptions. // We must throw here -- it's part of the IEnumerator contract. #pragma warning suppress 6503 throw new InvalidOperationException(SR.Get(SRID.EnumeratorNotStarted)); } // Check _currentCache before looking at _navigator. For the // last item in the enumeration, _navigator == _end, but // that's ok, the previous get_Current call (which sets _currentCache // non-null) put it there. if (_currentCache != null) { return _currentCache; } if (_navigator.CompareTo(_end) >= 0) { #pragma warning suppress 6503 // IEnumerator.Current is documented to throw this exception throw new InvalidOperationException(SR.Get(SRID.EnumeratorReachedEnd)); } // Throw if the tree has been modified since this enumerator was created. if (_generation != _start.TextContainer.Generation) { #pragma warning suppress 6503 // IEnumerator.Current is documented to throw this exception throw new InvalidOperationException(SR.Get(SRID.EnumeratorVersionChanged)); } switch (_navigator.GetPointerContext(LogicalDirection.Forward)) { case TextPointerContext.Text: offset = 0; // Merge all successive text runs into a single value. do { runLength = _navigator.GetTextRunLength(LogicalDirection.Forward); EnsureBufferCapacity(offset + runLength); _navigator.GetTextInRun(LogicalDirection.Forward, _buffer, offset, runLength); offset += runLength; _navigator.MoveToNextContextPosition(LogicalDirection.Forward); } while (_navigator.GetPointerContext(LogicalDirection.Forward) == TextPointerContext.Text); _currentCache = new string(_buffer, 0, offset); // _navigator is at next content. break; case TextPointerContext.EmbeddedElement: _currentCache = _navigator.GetAdjacentElement(LogicalDirection.Forward); // Position _navigator at next content. _navigator.MoveToNextContextPosition(LogicalDirection.Forward); break; case TextPointerContext.ElementStart: // Return the element, and advance past its entire content. _navigator.MoveToNextContextPosition(LogicalDirection.Forward); _currentCache = _navigator.Parent; // Position _navigator at next content. _navigator.MoveToElementEdge(ElementEdge.AfterEnd); break; default: Invariant.Assert(false, "Unexpected run type!"); _currentCache = null; // We should never get here. break; } return _currentCache; } } ////// Advance the enumerator to the next object in the range. Return true if content /// was found. /// public bool MoveNext() { // Throw if the tree has been modified since this enumerator was created. if (_start != null && _generation != _start.TextContainer.Generation) { throw new InvalidOperationException(SR.Get(SRID.EnumeratorVersionChanged)); } if (_start == null || _start.CompareTo(_end) == 0) return false; if (_navigator != null && _navigator.CompareTo(_end) >= 0) { return false; } if (_navigator == null) { _navigator = new TextPointer(_start); } else if (_currentCache == null) // If we have a cache, _navigator is already positioned at the next item. { switch (_navigator.GetPointerContext(LogicalDirection.Forward)) { case TextPointerContext.Text: // Skip all successive text runs as a single value. do { _navigator.MoveToNextContextPosition(LogicalDirection.Forward); } while (_navigator.GetPointerContext(LogicalDirection.Forward) == TextPointerContext.Text && _navigator.CompareTo(_end) < 0); break; case TextPointerContext.EmbeddedElement: _navigator.MoveToNextContextPosition(LogicalDirection.Forward); break; case TextPointerContext.ElementStart: // Return the element, and advance past its entire content. _navigator.MoveToNextContextPosition(LogicalDirection.Forward); _navigator.MoveToPosition(((TextElement)_navigator.Parent).ElementEnd); break; default: Invariant.Assert(false, "Unexpected run type!"); break; } } _currentCache = null; return (_navigator.CompareTo(_end) < 0); } ////// Reset the enumerator to the start of the range. /// public void Reset() { // Throw if the tree has been modified since this enumerator was created. if (_start != null && _generation != _start.TextContainer.Generation) { throw new InvalidOperationException(SR.Get(SRID.EnumeratorVersionChanged)); } _navigator = null; } #endregion Public Methods //------------------------------------------------------ // // Public Properties // //------------------------------------------------------ #region Public Properties #endregion Public Properties //----------------------------------------------------- // // Public Events // //------------------------------------------------------ #region Public Events #endregion Public Events //----------------------------------------------------- // // Protected Methods // //----------------------------------------------------- #region Protected Methods #endregion Protected Events //----------------------------------------------------- // // Internal Methods // //------------------------------------------------------ #region Internal Methods #endregion Internal methods //----------------------------------------------------- // // Internal Properties // //------------------------------------------------------ #region Internal Properties #endregion Internal Properties //------------------------------------------------------ // // Internal Events // //----------------------------------------------------- #region Internal Events #endregion Internal Events //------------------------------------------------------ // // Private Methods // //----------------------------------------------------- #region Private Methods private void EnsureBufferCapacity(int size) { char [] newBuffer; if (_buffer == null) { _buffer = new char[size]; } else if (_buffer.Length < size) { newBuffer = new char[Math.Max(2*_buffer.Length, size)]; _buffer.CopyTo(newBuffer, 0); _buffer = newBuffer; } } #endregion Private methods //----------------------------------------------------- // // Private Properties // //----------------------------------------------------- #region Private Properties #endregion Private Properties //------------------------------------------------------ // // Private Fields // //----------------------------------------------------- #region Private Fields // Edges of the span to enumerator over. private readonly TextPointer _start; private readonly TextPointer _end; // Backing store generation when this enumerator was created. private readonly uint _generation; // Current position in the enumeration. private TextPointer _navigator; // Calculated content at the current position. private object _currentCache; // Buffer to text content retrieval. private char [] _buffer; #endregion Private Fields } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. 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