fdf4442163
git-svn-id: file:///srv/devel/repo-conversion/nusu@329 d2e56fa2-650e-0410-a79f-9358c0239efd
96 lines
3.6 KiB
C#
96 lines
3.6 KiB
C#
#region CPL License
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/*
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Nuclex Framework
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Copyright (C) 2002-2017 Nuclex Development Labs
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This library is free software; you can redistribute it and/or
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modify it under the terms of the IBM Common Public License as
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published by the IBM Corporation; either version 1.0 of the
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License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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IBM Common Public License for more details.
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You should have received a copy of the IBM Common Public
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License along with this library
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*/
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#endregion
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using System;
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using System.Text;
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using System.IO;
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namespace Nuclex.Support {
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/// <summary>Utility class for path operations</summary>
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public static class PathHelper {
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/// <summary>Converts an absolute path into a relative one</summary>
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/// <param name="basePath">Base directory the new path should be relative to</param>
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/// <param name="absolutePath">Absolute path that will be made relative</param>
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/// <returns>
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/// A path relative to the indicated base directory that matches the
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/// absolute path given.
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/// </returns>
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public static string MakeRelative(string basePath, string absolutePath) {
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string[] baseDirectories = basePath.Split(Path.DirectorySeparatorChar);
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string[] absoluteDirectories = absolutePath.Split(Path.DirectorySeparatorChar);
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// Find the common root path of both paths so we know from which point on
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// the two paths will differ
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int lastCommonRoot = -1;
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int commonLength = Math.Min(baseDirectories.Length, absoluteDirectories.Length);
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for(int index = 0; index < commonLength; ++index) {
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if(absoluteDirectories[index] == baseDirectories[index]) {
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lastCommonRoot = index;
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} else {
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break;
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}
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}
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// If the paths don't share a common root, we have to use an absolute path.
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// Should the absolutePath parameter actually be a relative path, this will
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// also trigger the return of the absolutePath as-is.
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if(lastCommonRoot == -1) {
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return absolutePath;
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}
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// Calculate the required length for the StringBuilder in order to be slightly
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// more friendly in terms of memory usage.
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int requiredLength = (baseDirectories.Length - (lastCommonRoot + 1)) * 3;
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for(int index = lastCommonRoot + 1; index < absoluteDirectories.Length; ++index) {
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requiredLength += absoluteDirectories[index].Length + 1;
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}
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StringBuilder relativePath = new StringBuilder(requiredLength);
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// Go to the common path by adding .. until we're where we want to be
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for(int index = lastCommonRoot + 1; index < baseDirectories.Length; ++index) {
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if(baseDirectories[index].Length > 0) {
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if(relativePath.Length > 0) { // We don't want the path to start with a slash
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relativePath.Append(Path.DirectorySeparatorChar);
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}
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relativePath.Append("..");
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}
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}
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// Now that we're in the common root folder, enter the folders that
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// the absolute target path has in addition to the root folder.
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for(int index = lastCommonRoot + 1; index < absoluteDirectories.Length; index++) {
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if(relativePath.Length > 0) { // We don't want the path to start with a slash
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relativePath.Append(Path.DirectorySeparatorChar);
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}
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relativePath.Append(absoluteDirectories[index]);
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}
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return relativePath.ToString();
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}
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}
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} // namespace Nuclex.Support
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