unix、dos、Mac文件格式转换 C#

最近有个需求，xml文件修改时dos格式要变成unix格式，查找了一下三个文件的区别在于换行符
unix格式：-LF(\n)
dos格式：-LF/CR(\r\n)
mac格式：-CR(\r)
C#后台代码

  public class ConvertFileHelper
        {
            public enum FileType
            {
                DOS,
                UNIX,
                MAC
            }

            private const byte CR = 0x0D;//\r
            private const byte LF = 0x0A;//\n
            private static readonly byte[] DOS_LINE_ENDING = new byte[] { CR, LF };

            public static FileType DetermineFileFormat(string fileName)
            {
                byte[] data = File.ReadAllBytes(fileName);
                int position = 0;
                if (Array.IndexOf(data, LF, position) >= 0)
                {
                    if (Array.IndexOf(data, CR, position) >= 0)
                    {
                        return FileType.DOS;
                    }
                    return FileType.UNIX;

                }
                if (Array.IndexOf(data, CR, position) >= 0)
                {
                    return FileType.MAC;
                }
                return FileType.DOS;
            }

            public static void AutoFileTypeConvert(string fileName, FileType fileType)
            {
                FileType oldFileType = DetermineFileFormat(fileName);

                if (fileType == FileType.DOS)
                {
                    if (oldFileType == FileType.DOS)
                        return;
                    else if (oldFileType == FileType.UNIX)
                        Unix2Dos(fileName);
                    else if (oldFileType == FileType.MAC)
                        Mac2Dos(fileName);
                }
                else if (fileType == FileType.UNIX)
                {
                    if (oldFileType == FileType.UNIX)
                        return;
                    else if (oldFileType == FileType.DOS)
                        Dos2Unix(fileName);
                    else if (oldFileType == FileType.MAC)
                        Mac2Unix(fileName);
                }
                else if (fileType == FileType.MAC)
                {
                    if (oldFileType == FileType.MAC)
                        return;
                    else if (oldFileType == FileType.DOS)
                        Dos2Mac(fileName);
                    else if (oldFileType == FileType.UNIX)
                        Unix2Mac(fileName);
                }
            }

            public static void Unix2Dos(string fileName)
            {
                byte[] data = File.ReadAllBytes(fileName);
                using (FileStream fileStream = File.OpenWrite(fileName))
                {
                    BinaryWriter bw = new BinaryWriter(fileStream);
                    int position = 0;
                    int index = 0;
                    do
                    {
                        index = Array.IndexOf(data, LF, position);
                        if (index >= 0)
                        {
                            if (index > 0 && data[index - 1] == CR)
                            {
                                bw.Write(data, position, index - position + 1);
                            }
                            else
                            {
                                bw.Write(data, position, index - position);
                                bw.Write(DOS_LINE_ENDING);
                            }
                            position = index + 1;
                        }
                    }
                    while (index >= 0);
                    bw.Write(data, position, data.Length - position);
                    fileStream.SetLength(fileStream.Position);
                }
            }

            public static void Mac2Dos(string fileName)
            {
                byte[] data = File.ReadAllBytes(fileName);
                int len = data.Length - 1;
                using (FileStream fileStream = File.OpenWrite(fileName))
                {
                    BinaryWriter bw = new BinaryWriter(fileStream);
                    int position = 0;
                    int index = 0;
                    do
                    {
                        index = Array.IndexOf(data, CR, position);
                        if (index >= 0)
                        {
                            if (index >= 0 && index < len && data[index + 1] == LF)
                            {
                                bw.Write(data, position, index - position + 1);
                            }
                            else
                            {
                                bw.Write(data, position, index - position);
                                bw.Write(DOS_LINE_ENDING);
                            }
                            position = index + 1;
                        }
                    } while (index >= 0);
                    bw.Write(data, position, data.Length - position);
                    fileStream.SetLength(fileStream.Position);
                }
            }

            public static void Dos2Unix(string fileName)
            {
                byte[] data = File.ReadAllBytes(fileName);
                using (FileStream fileStream = File.OpenWrite(fileName))
                {
                    BinaryWriter bw = new BinaryWriter(fileStream);
                    int position = 0;
                    int index = 0;
                    do
                    {
                        index = Array.IndexOf(data, CR, position);
                        if (index >= 0)
                        {
                            if (index > 0 && data[index + 1] == LF)
                            {
                                bw.Write(data, position, index - position);
                            }
                            else
                            {
                                bw.Write(data, position, index - position + 1);
                            }
                            position = index + 1;
                        }
                    }
                    while (index >= 0);
                    bw.Write(data, position, data.Length - position);
                    fileStream.SetLength(fileStream.Position);
                }
            }

            public static void Dos2Mac(string fileName)
            {
                byte[] data = File.ReadAllBytes(fileName);
                using (FileStream fileStream = File.OpenWrite(fileName))
                {
                    BinaryWriter bw = new BinaryWriter(fileStream);
                    int position = 0;
                    int index = 0;
                    do
                    {
                        index = Array.IndexOf(data, LF, position);
                        if (index >= 0)
                        {
                            if (index > 0 && data[index - 1] == CR)
                            {
                                bw.Write(data, position, index - position);
                            }
                            else
                            {
                                bw.Write(data, position, index - position + 1);
                            }
                            position = index + 1;
                        }
                    }
                    while (index >= 0);
                    bw.Write(data, position, data.Length - position);
                    fileStream.SetLength(fileStream.Position);
                }
            }

            public static void Mac2Unix(string fileName)
            {
                byte[] data = File.ReadAllBytes(fileName);
                int len = data.Length - 1;
                using (FileStream fileStream = File.OpenWrite(fileName))
                {
                    BinaryWriter bw = new BinaryWriter(fileStream);
                    int position = 0;
                    int index = 0;
                    do
                    {
                        index = Array.IndexOf(data, CR, position);
                        if (index >= 0)
                        {
                            if (index >= 0 && index < len && data[index + 1] == LF)
                            {
                                bw.Write(data, position, index - position + 1);
                            }
                            else
                            {
                                bw.Write(data, position, index - position);
                                bw.Write(LF);
                            }
                            position = index + 1;
                        }
                    } while (index >= 0);
                    bw.Write(data, position, data.Length - position);
                    fileStream.SetLength(fileStream.Position);
                }
            }

            public static void Unix2Mac(string fileName)
            {
                byte[] data = File.ReadAllBytes(fileName);
                using (FileStream fileStream = File.OpenWrite(fileName))
                {
                    BinaryWriter bw = new BinaryWriter(fileStream);
                    int position = 0;
                    int index = 0;
                    do
                    {
                        index = Array.IndexOf(data, LF, position);
                        if (index >= 0)
                        {
                            if (index > 0 && data[index - 1] == CR)
                            {
                                bw.Write(data, position, index - position + 1);
                            }
                            else
                            {
                                bw.Write(data, position, index - position);
                                bw.Write(CR);
                            }
                            position = index + 1;
                        }
                    }
                    while (index >= 0);
                    bw.Write(data, position, data.Length - position);
                    fileStream.SetLength(fileStream.Position);
                }
            }
        }