[gnome-subtitles] Don't write UTF-8 files with BOM

[Pedro Castro <pcastro src gnome org>]

commit f117bf70a600c1074833aab97a5a2c807786f79e
Author: Pedro Castro <pedro gnomesubtitles org>
Date:   Sun Oct 28 17:51:29 2018 +0000

    Don't write UTF-8 files with BOM
    
    Fixes #113 - Don't insert the BOM (Byte order mark) when saving files
    with UTF-8 encoding

 src/GnomeSubtitles/Core/Document.cs  |  6 +++---
 src/GnomeSubtitles/Core/Encodings.cs | 25 ++++++++++++++++++++-----
 src/GnomeSubtitles/Ui/MainUi.cs      |  6 +++---
 3 files changed, 26 insertions(+), 11 deletions(-)
---
diff --git a/src/GnomeSubtitles/Core/Document.cs b/src/GnomeSubtitles/Core/Document.cs
index 2819e1c..edeee5f 100644
--- a/src/GnomeSubtitles/Core/Document.cs
+++ b/src/GnomeSubtitles/Core/Document.cs
@@ -1,6 +1,6 @@
 /*
  * This file is part of Gnome Subtitles.
- * Copyright (C) 2006-2017 Pedro Castro
+ * Copyright (C) 2006-2018 Pedro Castro
  *
  * Gnome Subtitles is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -262,12 +262,12 @@ public class Document {
        private Encoding GetFallbackEncoding () {
                ConfigFileOpenFallbackEncoding fallbackEncodingConfig = Base.Config.FileOpenFallbackEncoding;
                if (fallbackEncodingConfig == ConfigFileOpenFallbackEncoding.CurrentLocale)
-                       return Encoding.GetEncoding(Encodings.SystemDefault.CodePage);
+                       return Encodings.GetEncoding(Encodings.SystemDefault.CodePage);
                else {
                        string encodingName = Base.Config.FileOpenFallbackEncodingFixed;
                        EncodingDescription encodingDescription = EncodingDescription.Empty;
                        Encodings.Find(encodingName, ref encodingDescription);
-                       return Encoding.GetEncoding(encodingDescription.CodePage);
+                       return Encodings.GetEncoding(encodingDescription.CodePage);
                }
        }
 
diff --git a/src/GnomeSubtitles/Core/Encodings.cs b/src/GnomeSubtitles/Core/Encodings.cs
index fc6be9c..c8b766a 100644
--- a/src/GnomeSubtitles/Core/Encodings.cs
+++ b/src/GnomeSubtitles/Core/Encodings.cs
@@ -1,6 +1,6 @@
 /*
  * This file is part of Gnome Subtitles.
- * Copyright (C) 2007-2010 Pedro Castro
+ * Copyright (C) 2007-2018 Pedro Castro
  *
  * Gnome Subtitles is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -25,6 +25,10 @@ namespace GnomeSubtitles.Core {
 
 public class Encodings {
 
+       /* UTF8 encoding is constructed in a different manner in order to disable the BOM. */
+       private static int CODEPAGE_UTF8 = 65001;
+       private static Encoding encodingUTF8 = null;
+
        /* The original versions of the following tables were taken from gedit
         * which on the other hand took them from profterm
         * Copyright (C) 2002 Red Hat, Inc.
@@ -46,12 +50,12 @@ public class Encodings {
                new EncodingDescription(28606, "ISO-8859-16", Catalog.GetString("Romanian")),
                /* ISO-8859-8-I not used */
 
-               new EncodingDescription(65001, "UTF-8", Catalog.GetString("Unicode")), /* Added */
+               new EncodingDescription(CODEPAGE_UTF8, "UTF-8", Catalog.GetString("Unicode")), /* Added */
                new EncodingDescription(65000, "UTF-7", Catalog.GetString("Unicode")),
-               new EncodingDescription(1200, "UTF-16", Catalog.GetString("Unicode")),
+               new EncodingDescription(1200, "UTF-16", Catalog.GetString("Unicode")), //Little endian
                new EncodingDescription(1201, "UTF-16BE", Catalog.GetString("Unicode")),
                new EncodingDescription(1200, "UTF-16LE", Catalog.GetString("Unicode")),
-               new EncodingDescription(12000, "UTF-32", Catalog.GetString("Unicode")),
+               new EncodingDescription(12000, "UTF-32", Catalog.GetString("Unicode")), //Little endian
                new EncodingDescription(12001, "UTF-32BE", Catalog.GetString("Unicode")), /* Added */
                new EncodingDescription(12000, "UTF-32LE", Catalog.GetString("Unicode")), /* Added */
                /* UCS-2 and UCS-4 not used */
@@ -163,7 +167,7 @@ public class Encodings {
                        return desc.Name;
 
                try {
-                       Encoding encoding = Encoding.GetEncoding(codePage);
+                       Encoding encoding = GetEncoding(codePage);
                        if (encoding != null)
                                return encoding.WebName;
                }
@@ -172,6 +176,17 @@ public class Encodings {
                }
                return null;
        }
+       
+       public static Encoding GetEncoding (int codePage) {
+               if (codePage == CODEPAGE_UTF8) {
+                       if (encodingUTF8 == null) {
+                               encodingUTF8 = new UTF8Encoding(false);
+                       }
+                       return encodingUTF8;
+               }
+
+               return Encoding.GetEncoding(codePage);
+       }
 
 }
 
diff --git a/src/GnomeSubtitles/Ui/MainUi.cs b/src/GnomeSubtitles/Ui/MainUi.cs
index 6bdce5a..e09563e 100644
--- a/src/GnomeSubtitles/Ui/MainUi.cs
+++ b/src/GnomeSubtitles/Ui/MainUi.cs
@@ -299,7 +299,7 @@ public class MainUi {
                return null;
 
        try {
-               return Encoding.GetEncoding(codePage);
+               return Encodings.GetEncoding(codePage);
        }
        catch (NotSupportedException) {
                throw new EncodingNotSupportedException();
@@ -312,7 +312,7 @@ public class MainUi {
        /// <remarks>An error dialog is presented if an exception is caught during open.</remarks>
     private void OpenTranslation (string path, int codePage) {
        try {
-               Encoding encoding = (codePage == -1 ? null : Encoding.GetEncoding(codePage));
+               Encoding encoding = (codePage == -1 ? null : Encodings.GetEncoding(codePage));
                Base.OpenTranslation(path, encoding);
                }
                catch (Exception exception) {
@@ -362,7 +362,7 @@ public class MainUi {
                        return null;
 
                string path = dialog.Filename;
-               Encoding encoding = Encoding.GetEncoding(dialog.Encoding.CodePage);
+               Encoding encoding = Encodings.GetEncoding(dialog.Encoding.CodePage);
                SubtitleType subtitleType = dialog.SubtitleType;
                NewlineType newlineType = dialog.NewlineType;
                TimingMode timingMode = Base.TimingMode;