source: branches/3107_LearningALPS/HeuristicLab.ExtLibs/HeuristicLab.AvalonEdit/5.0.1/AvalonEdit-5.0.1/Document/NewLineFinder.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.Text;
#if NREFACTORY
using ICSharpCode.NRefactory.Editor;
#endif

namespace ICSharpCode.AvalonEdit.Document
{
  static class NewLineFinder
  {
    static readonly char[] newline = { '\r', '\n' };
    
    internal static readonly string[] NewlineStrings = { "\r\n", "\r", "\n" };
    
    /// <summary>
    /// Gets the location of the next new line character, or SimpleSegment.Invalid
    /// if none is found.
    /// </summary>
    internal static SimpleSegment NextNewLine(string text, int offset)
    {
      int pos = text.IndexOfAny(newline, offset);
      if (pos >= 0) {
        if (text[pos] == '\r') {
          if (pos + 1 < text.Length && text[pos + 1] == '\n')
            return new SimpleSegment(pos, 2);
        }
        return new SimpleSegment(pos, 1);
      }
      return SimpleSegment.Invalid;
    }
    
    /// <summary>
    /// Gets the location of the next new line character, or SimpleSegment.Invalid
    /// if none is found.
    /// </summary>
    internal static SimpleSegment NextNewLine(ITextSource text, int offset)
    {
      int textLength = text.TextLength;
      int pos = text.IndexOfAny(newline, offset, textLength - offset);
      if (pos >= 0) {
        if (text.GetCharAt(pos) == '\r') {
          if (pos + 1 < textLength && text.GetCharAt(pos + 1) == '\n')
            return new SimpleSegment(pos, 2);
        }
        return new SimpleSegment(pos, 1);
      }
      return SimpleSegment.Invalid;
    }
  }
  
  partial class TextUtilities
  {
    /// <summary>
    /// Finds the next new line character starting at offset.
    /// </summary>
    /// <param name="text">The text source to search in.</param>
    /// <param name="offset">The starting offset for the search.</param>
    /// <param name="newLineType">The string representing the new line that was found, or null if no new line was found.</param>
    /// <returns>The position of the first new line starting at or after <paramref name="offset"/>,
    /// or -1 if no new line was found.</returns>
    public static int FindNextNewLine(ITextSource text, int offset, out string newLineType)
    {
      if (text == null)
        throw new ArgumentNullException("text");
      if (offset < 0 || offset > text.TextLength)
        throw new ArgumentOutOfRangeException("offset", offset, "offset is outside of text source");
      SimpleSegment s = NewLineFinder.NextNewLine(text, offset);
      if (s == SimpleSegment.Invalid) {
        newLineType = null;
        return -1;
      } else {
        if (s.Length == 2) {
          newLineType = "\r\n";
        } else if (text.GetCharAt(s.Offset) == '\n') {
          newLineType = "\n";
        } else {
          newLineType = "\r";
        }
        return s.Offset;
      }
    }
    
    /// <summary>
    /// Gets whether the specified string is a newline sequence.
    /// </summary>
    public static bool IsNewLine(string newLine)
    {
      return newLine == "\r\n" || newLine == "\n" || newLine == "\r";
    }
    
    /// <summary>
    /// Normalizes all new lines in <paramref name="input"/> to be <paramref name="newLine"/>.
    /// </summary>
    public static string NormalizeNewLines(string input, string newLine)
    {
      if (input == null)
        return null;
      if (!IsNewLine(newLine))
        throw new ArgumentException("newLine must be one of the known newline sequences");
      SimpleSegment ds = NewLineFinder.NextNewLine(input, 0);
      if (ds == SimpleSegment.Invalid) // text does not contain any new lines
        return input;
      StringBuilder b = new StringBuilder(input.Length);
      int lastEndOffset = 0;
      do {
        b.Append(input, lastEndOffset, ds.Offset - lastEndOffset);
        b.Append(newLine);
        lastEndOffset = ds.EndOffset;
        ds = NewLineFinder.NextNewLine(input, lastEndOffset);
      } while (ds != SimpleSegment.Invalid);
      // remaining string (after last newline)
      b.Append(input, lastEndOffset, input.Length - lastEndOffset);
      return b.ToString();
    }
    
    /// <summary>
    /// Gets the newline sequence used in the document at the specified line.
    /// </summary>
    public static string GetNewLineFromDocument(IDocument document, int lineNumber)
    {
      IDocumentLine line = document.GetLineByNumber(lineNumber);
      if (line.DelimiterLength == 0) {
        // at the end of the document, there's no line delimiter, so use the delimiter
        // from the previous line
        line = line.PreviousLine;
        if (line == null)
          return Environment.NewLine;
      }
      return document.GetText(line.Offset + line.Length, line.DelimiterLength);
    }
  }
}