source: branches/RemoveBackwardsCompatibility/HeuristicLab.ExtLibs/HeuristicLab.AvalonEdit/5.0.1/AvalonEdit-5.0.1/Editing/SimpleSelection.cs

// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

using System;
using System.Collections.Generic;
using ICSharpCode.AvalonEdit.Document;
using ICSharpCode.AvalonEdit.Utils;
#if NREFACTORY
using ICSharpCode.NRefactory.Editor;
#endif

namespace ICSharpCode.AvalonEdit.Editing
{
  /// <summary>
  /// A simple selection.
  /// </summary>
  public sealed class SimpleSelection : Selection
  {
    readonly TextViewPosition start, end;
    readonly int startOffset, endOffset;
    
    /// <summary>
    /// Creates a new SimpleSelection instance.
    /// </summary>
    public SimpleSelection(TextArea textArea, TextViewPosition start, TextViewPosition end)
      : base(textArea)
    {
      this.start = start;
      this.end = end;
      this.startOffset = textArea.Document.GetOffset(start.Location);
      this.endOffset = textArea.Document.GetOffset(end.Location);
    }
    
    /// <inheritdoc/>
    public override IEnumerable<SelectionSegment> Segments {
      get {
        return ExtensionMethods.Sequence<SelectionSegment>(new SelectionSegment(startOffset, start.VisualColumn, endOffset, end.VisualColumn));
      }
    }
    
    /// <inheritdoc/>
    public override ISegment SurroundingSegment {
      get {
        return new SelectionSegment(startOffset, endOffset);
      }
    }
    
    /// <inheritdoc/>
    public override void ReplaceSelectionWithText(string newText)
    {
      if (newText == null)
        throw new ArgumentNullException("newText");
      using (textArea.Document.RunUpdate()) {
        ISegment[] segmentsToDelete = textArea.GetDeletableSegments(this.SurroundingSegment);
        for (int i = segmentsToDelete.Length - 1; i >= 0; i--) {
          if (i == segmentsToDelete.Length - 1) {
            if (segmentsToDelete[i].Offset == SurroundingSegment.Offset && segmentsToDelete[i].Length == SurroundingSegment.Length) {
              newText = AddSpacesIfRequired(newText, start, end);
            }
            if (string.IsNullOrEmpty(newText)) {
              // place caret at the beginning of the selection
              if (start.CompareTo(end) <= 0)
                textArea.Caret.Position = start;
              else
                textArea.Caret.Position = end;
            } else {
              // place caret so that it ends up behind the new text
              textArea.Caret.Offset = segmentsToDelete[i].EndOffset;
            }
            textArea.Document.Replace(segmentsToDelete[i], newText);
          } else {
            textArea.Document.Remove(segmentsToDelete[i]);
          }
        }
        if (segmentsToDelete.Length != 0) {
          textArea.ClearSelection();
        }
      }
    }
    
    public override TextViewPosition StartPosition {
      get { return start; }
    }
    
    public override TextViewPosition EndPosition {
      get { return end; }
    }
    
    /// <inheritdoc/>
    public override Selection UpdateOnDocumentChange(DocumentChangeEventArgs e)
    {
      if (e == null)
        throw new ArgumentNullException("e");
      int newStartOffset, newEndOffset;
      if (startOffset <= endOffset) {
        newStartOffset = e.GetNewOffset(startOffset, AnchorMovementType.Default);
        newEndOffset = Math.Max(newStartOffset, e.GetNewOffset(endOffset, AnchorMovementType.BeforeInsertion));
      } else {
        newEndOffset = e.GetNewOffset(endOffset, AnchorMovementType.Default);
        newStartOffset = Math.Max(newEndOffset, e.GetNewOffset(startOffset, AnchorMovementType.BeforeInsertion));
      }
      return Selection.Create(
        textArea,
        new TextViewPosition(textArea.Document.GetLocation(newStartOffset), start.VisualColumn),
        new TextViewPosition(textArea.Document.GetLocation(newEndOffset), end.VisualColumn)
      );
    }
    
    /// <inheritdoc/>
    public override bool IsEmpty {
      get { return startOffset == endOffset && start.VisualColumn == end.VisualColumn; }
    }
    
    /// <inheritdoc/>
    public override int Length {
      get {
        return Math.Abs(endOffset - startOffset);
      }
    }
    
    /// <inheritdoc/>
    public override Selection SetEndpoint(TextViewPosition endPosition)
    {
      return Create(textArea, start, endPosition);
    }
    
    public override Selection StartSelectionOrSetEndpoint(TextViewPosition startPosition, TextViewPosition endPosition)
    {
      var document = textArea.Document;
      if (document == null)
        throw ThrowUtil.NoDocumentAssigned();
      return Create(textArea, start, endPosition);
    }
    
    /// <inheritdoc/>
    public override int GetHashCode()
    {
      unchecked {
        return startOffset * 27811 + endOffset + textArea.GetHashCode();
      }
    }
    
    /// <inheritdoc/>
    public override bool Equals(object obj)
    {
      SimpleSelection other = obj as SimpleSelection;
      if (other == null) return false;
      return this.start.Equals(other.start) && this.end.Equals(other.end)
        && this.startOffset == other.startOffset && this.endOffset == other.endOffset
        && this.textArea == other.textArea;
    }
    
    /// <inheritdoc/>
    public override string ToString()
    {
      return "[SimpleSelection Start=" + start + " End=" + end + "]";
    }
  }
}