src/OneScript.Core/Commons/FileOpener.cs - develop - smwwiki/OneScript_fork

src/OneScript.Core/Commons/FileOpener.cs
110 строк4 KB
EvilBeaver
Вливание из develop
02 май 2022, 23:14
02 май 2022, 23:14b49ca41
/*----------------------------------------------------------
This Source Code Form is subject to the terms of the 
Mozilla Public License, v.2.0. If a copy of the MPL 
was not distributed with this file, You can obtain one 
at http://mozilla.org/MPL/2.0/.
----------------------------------------------------------*/

using System;
using System.IO;
using System.Text;

namespace OneScript.Commons
{
    public static class FileOpener
    {
        public static StreamReader OpenReader(string filename)
        {
            return OpenReader(filename, FileShare.ReadWrite);
        }
        
        public static StreamReader OpenReader(string filename, FileShare shareMode, Encoding encoding = null)
        {
            var input = new FileStream(filename, FileMode.Open, FileAccess.Read, shareMode);

            if (encoding == null)
            {
                var enc = AssumeEncoding(input);
                return new StreamReader(input, enc, true);
            }

            return new StreamReader(input, encoding);
        }

        public static StreamReader OpenReader(string filename, Encoding encoding)
        {
            return OpenReader(filename, FileShare.ReadWrite, encoding);
        }

        public static StreamReader OpenReader(Stream stream, Encoding encoding = null)
        {
            if(encoding == null)
            {
                var enc = AssumeEncoding(stream);
                return new StreamReader(stream, enc, true);
            }
            return new StreamReader(stream, encoding);
        }

        public static StreamWriter OpenWriter(string filename)
        {
            var utf8BOMEncoding = new UTF8Encoding(true);
            return new StreamWriter(filename, false, utf8BOMEncoding);
        }

        public static StreamWriter OpenWriter(string filename, Encoding encoding)
        {
            return new StreamWriter(filename, false, encoding);
        }

        public static StreamWriter OpenWriter(string filename, Encoding encoding, bool append)
        {
            return new StreamWriter(filename, append, encoding);
        }

        public static Encoding AssumeEncoding(Stream inputStream)
        {
            return AssumeEncoding(inputStream, SystemSpecificEncoding());
        }

        public static Encoding SystemSpecificEncoding()
        {
            if(Environment.OSVersion.Platform == PlatformID.Unix || Environment.OSVersion.Platform == PlatformID.MacOSX)
            {
                return Encoding.UTF8;
            }

            return Encoding.Default;
        }

        public static Encoding AssumeEncoding(Stream inputStream, Encoding fallbackEncoding)
        {
            var enc = fallbackEncoding;

            // *** Detect byte order mark if any - otherwise assume default
            byte[] buffer = new byte[4];

            inputStream.Read(buffer, 0, 4);
            inputStream.Position = 0;

            if (buffer[0] == 0xef && buffer[1] == 0xbb && buffer[2] == 0xbf)
                enc = Encoding.UTF8;
            else if (buffer[0] == 0xff && buffer[1] == 0xfe && buffer[2] == 0 && buffer[3] == 0)
                enc = Encoding.UTF32; // UTF32LE
            else if (buffer[0] == 0xff && buffer[1] == 0xfe)
                enc = Encoding.Unicode; // UTF16LE
            else if (buffer[0] == 0 && buffer[1] == 0 && buffer[2] == 0xfe && buffer[3] == 0xff)
                enc = new UTF32Encoding(true, true); // UTF32BE with BOM;
            else if (buffer[0] == 0xfe && buffer[1] == 0xff)
                enc = Encoding.BigEndianUnicode; // UTF16BE
            else if (buffer[0] == '#' && buffer[1] == '!') 
            {
                /* Если в начале файла присутствует shebang, считаем, что файл в UTF-8*/
                enc = Encoding.UTF8;
            }

            return enc;
        }

    }
}