74 lines
3.0 KiB
C#
74 lines
3.0 KiB
C#
/*
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*
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* (c) Copyright Ascensio System Limited 2010-2018
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*
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* This program is freeware. You can redistribute it and/or modify it under the terms of the GNU
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* General Public License (GPL) version 3 as published by the Free Software Foundation (https://www.gnu.org/copyleft/gpl.html).
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* In accordance with Section 7(a) of the GNU GPL its Section 15 shall be amended to the effect that
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* Ascensio System SIA expressly excludes the warranty of non-infringement of any third-party rights.
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*
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* THIS PROGRAM IS DISTRIBUTED WITHOUT ANY WARRANTY; WITHOUT EVEN THE IMPLIED WARRANTY OF MERCHANTABILITY OR
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* FITNESS FOR A PARTICULAR PURPOSE. For more details, see GNU GPL at https://www.gnu.org/copyleft/gpl.html
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*
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* You can contact Ascensio System SIA by email at sales@onlyoffice.com
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*
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* The interactive user interfaces in modified source and object code versions of ONLYOFFICE must display
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* Appropriate Legal Notices, as required under Section 5 of the GNU GPL version 3.
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*
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* Pursuant to Section 7 § 3(b) of the GNU GPL you must retain the original ONLYOFFICE logo which contains
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* relevant author attributions when distributing the software. If the display of the logo in its graphic
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* form is not reasonably feasible for technical reasons, you must include the words "Powered by ONLYOFFICE"
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* in every copy of the program you distribute.
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* Pursuant to Section 7 § 3(e) we decline to grant you any rights under trademark law for use of our trademarks.
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*
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*/
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using System;
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using System.Linq;
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using System.Text;
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namespace ASC.Common.Utils
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{
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public static class MimeHeaderUtils
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{
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public static string EncodeMime(string mimeHeaderValue)
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{
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return EncodeMime(mimeHeaderValue, Encoding.UTF8, false);
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}
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public static string EncodeMime(string mimeHeaderValue, Encoding charset, bool split)
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{
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if (MustEncode(mimeHeaderValue))
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{
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var result = new StringBuilder();
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var data = charset.GetBytes(mimeHeaderValue);
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var maxEncodedTextSize = split ? 75 - ("=?" + charset.WebName + "?" + "B"/*Base64 encode*/ + "?" + "?=").Length : int.MaxValue;
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result.Append("=?" + charset.WebName + "?B?");
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var stored = 0;
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var base64 = Convert.ToBase64String(data);
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for (var i = 0; i < base64.Length; i += 4)
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{
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// Encoding buffer full, create new encoded-word.
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if (stored + 4 > maxEncodedTextSize)
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{
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result.Append("?=\r\n =?" + charset.WebName + "?B?");
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stored = 0;
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}
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result.Append(base64, i, 4);
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stored += 4;
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}
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result.Append("?=");
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return result.ToString();
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}
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return mimeHeaderValue;
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}
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public static bool MustEncode(string text)
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{
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return !string.IsNullOrEmpty(text) && text.Any(c => c > 127);
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}
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}
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} |