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41 lines
1.3 KiB
C#
41 lines
1.3 KiB
C#
// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
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// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
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using System;
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using System.Collections.Generic;
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namespace ICSharpCode.Core
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{
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internal static class ExtensionMethods
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{
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/// <summary>
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/// Converts a recursive data structure into a flat list.
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/// </summary>
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/// <param name="input">The root elements of the recursive data structure.</param>
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/// <param name="recursion">The function that gets the children of an element.</param>
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/// <returns>Iterator that enumerates the tree structure in preorder.</returns>
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public static IEnumerable<T> Flatten<T>(this IEnumerable<T> input, Func<T, IEnumerable<T>> recursion)
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{
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Stack<IEnumerator<T>> stack = new Stack<IEnumerator<T>>();
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try {
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stack.Push(input.GetEnumerator());
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while (stack.Count > 0) {
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while (stack.Peek().MoveNext()) {
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T element = stack.Peek().Current;
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yield return element;
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IEnumerable<T> children = recursion(element);
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if (children != null) {
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stack.Push(children.GetEnumerator());
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}
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}
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stack.Pop().Dispose();
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}
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} finally {
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while (stack.Count > 0) {
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stack.Pop().Dispose();
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}
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}
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}
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}
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}
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