File Stream C#

/*
 * Filename:    FileUtil.cs
 * Product:     Versioning Controlled Build
 * Solution:    BuildAutoIncrement
 * Project:     Shared
 * Description: File utility methods.
 * Copyright:   Julijan ?ribar, 2004-2007
 * 
 * This software is provided 'as-is', without any express or implied
 * warranty.  In no event will the author(s) be held liable for any damages
 * arising from the use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 *    claim that you wrote the original software. If you use this software
 *    in a product, an acknowledgment in the product documentation would be
 *    appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 */
using System;
using System.Diagnostics;
using System.IO;
using System.Text;
using System.Text.RegularExpressions;
namespace BuildAutoIncrement {
    /// 
  /// A set of file utilities.
  /// 

  public struct FileUtil {
        /// 
        ///   Creates a relative path from absolute pathfilename and a 
        ///   reference path.
        /// 

        /// 
        ///   Absolute pathfilename for which relative pathfilename has to be
        ///   created.
        /// 
        /// 
        ///   Reference path.
        /// 
        /// 
        ///   Returns relative pathfilename. If pathfilename and reference path
        ///   do not have common part (e.g. from different drive), absolute 
        ///   filepathname is returned.
        /// 

        public static string GetRelativePathfilename(string pathfilename, string referencePath) {
            Debug.Assert(pathfilename != null && pathfilename.Length > 0);
            Debug.Assert(referencePath != null && referencePath.Length > 0);
            Debug.Assert(Path.IsPathRooted(pathfilename));
            Debug.Assert(Path.IsPathRooted(referencePath));
            // split both pathnames into directory names constituting path name
            string[] pathfilenameSections = pathfilename.Split(DirectorySeparators);
            string[] referencePathSections = referencePath.Split(DirectorySeparators);
            StringBuilder relativePath = new StringBuilder();
            int pathSectionCounter = 0;
            // skip leading backslashes for the case of UNC path name
            if (pathfilename.StartsWith("\\\\") && referencePath.StartsWith("\\\\"))
                pathSectionCounter = 2;
            int filenameSectionCounter = pathSectionCounter;
            bool matchingFound = false;
            // scan for common parts of paths
            while ((pathSectionCounter < referencePathSections.Length) && (referencePathSections[pathSectionCounter].Length > 0)) {
                if (string.Compare(referencePathSections[pathSectionCounter], pathfilenameSections[pathSectionCounter], true) == 0)
                    matchingFound = true;
                else {
                    if (matchingFound) {
                        while ((pathSectionCounter < referencePathSections.Length) && (referencePathSections[pathSectionCounter].Length > 0)) {
                            relativePath.Append("..");
                            relativePath.Append(Path.DirectorySeparatorChar);
                            pathSectionCounter++;
                        }
                    }
                    break;
                }
                pathSectionCounter++;
                filenameSectionCounter++;
            }
            // no common starting sections - return absolute path
            if (!matchingFound)
                return pathfilename;
            // append filename path
            while (filenameSectionCounter < pathfilenameSections.Length) {
                relativePath.Append(pathfilenameSections[filenameSectionCounter]);
                filenameSectionCounter++;
                if (filenameSectionCounter < pathfilenameSections.Length)
                    relativePath.Append(Path.DirectorySeparatorChar);
            }
            return relativePath.ToString();
        }
                /// 
        ///   Directory separator characters.
        /// 

        public static readonly char[] DirectorySeparators = new char[] {Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar };
  }
}