121 lines
3.9 KiB
C#
121 lines
3.9 KiB
C#
// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy of this
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// software and associated documentation files (the "Software"), to deal in the Software
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// without restriction, including without limitation the rights to use, copy, modify, merge,
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// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
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// to whom the Software is furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in all copies or
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// substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
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// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
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// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
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// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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// DEALINGS IN THE SOFTWARE.
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using System;
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using System.Collections.Generic;
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using System.Diagnostics;
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using System.IO;
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namespace Unity.CodeEditor.Utils
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{
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/// <summary>
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/// TextReader implementation that reads text from a rope.
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/// </summary>
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internal sealed class RopeTextReader : TextReader
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{
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private readonly Stack<RopeNode<char>> _stack = new Stack<RopeNode<char>>();
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private RopeNode<char> _currentNode;
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private int _indexInsideNode;
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/// <summary>
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/// Creates a new RopeTextReader.
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/// Internally, this method creates a Clone of the rope; so the text reader will always read through the old
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/// version of the rope if it is modified. <seealso cref="Rope{T}.Clone()"/>
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/// </summary>
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internal RopeTextReader(Rope<char> rope)
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{
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if (rope == null)
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throw new ArgumentNullException(nameof(rope));
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// We force the user to iterate through a clone of the rope to keep the API contract of RopeTextReader simple
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// (what happens when a rope is modified while iterating through it?)
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rope.Root.Publish();
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// special case for the empty rope:
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// leave currentNode initialized to null (RopeTextReader doesn't support empty nodes)
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if (rope.Length != 0) {
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_currentNode = rope.Root;
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GoToLeftMostLeaf();
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}
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}
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private void GoToLeftMostLeaf()
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{
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while (_currentNode.Contents == null) {
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if (_currentNode.Height == 0) {
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// this is a function node - move to its contained rope
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_currentNode = _currentNode.GetContentNode();
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continue;
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}
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Debug.Assert(_currentNode.Right != null);
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_stack.Push(_currentNode.Right);
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_currentNode = _currentNode.Left;
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}
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Debug.Assert(_currentNode.Height == 0);
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}
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/// <inheritdoc/>
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public override int Peek()
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{
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if (_currentNode == null)
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return -1;
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return _currentNode.Contents[_indexInsideNode];
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}
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/// <inheritdoc/>
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public override int Read()
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{
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if (_currentNode == null)
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return -1;
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char result = _currentNode.Contents[_indexInsideNode++];
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if (_indexInsideNode >= _currentNode.Length)
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GoToNextNode();
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return result;
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}
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private void GoToNextNode()
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{
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if (_stack.Count == 0) {
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_currentNode = null;
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} else {
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_indexInsideNode = 0;
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_currentNode = _stack.Pop();
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GoToLeftMostLeaf();
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}
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}
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/// <inheritdoc/>
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public override int Read(char[] buffer, int index, int count)
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{
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if (_currentNode == null)
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return 0;
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int amountInCurrentNode = _currentNode.Length - _indexInsideNode;
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if (count < amountInCurrentNode) {
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Array.Copy(_currentNode.Contents, _indexInsideNode, buffer, index, count);
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_indexInsideNode += count;
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return count;
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} else {
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// read to end of current node
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Array.Copy(_currentNode.Contents, _indexInsideNode, buffer, index, amountInCurrentNode);
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GoToNextNode();
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return amountInCurrentNode;
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}
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}
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}
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}
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