73 lines
2.9 KiB
C#
73 lines
2.9 KiB
C#
// (c) Copyright Ascensio System SIA 2010-2022
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//
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// This program is a free software product.
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// You can redistribute it and/or modify it under the terms
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// of the GNU Affero General Public License (AGPL) version 3 as published by the Free Software
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// Foundation. In accordance with Section 7(a) of the GNU AGPL its Section 15 shall be amended
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// to the effect that Ascensio System SIA expressly excludes the warranty of non-infringement of
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// any third-party rights.
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//
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// This program is distributed WITHOUT ANY WARRANTY, without even the implied warranty
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// of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. For details, see
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// the GNU AGPL at: http://www.gnu.org/licenses/agpl-3.0.html
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//
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// You can contact Ascensio System SIA at Lubanas st. 125a-25, Riga, Latvia, EU, LV-1021.
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//
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// The interactive user interfaces in modified source and object code versions of the Program must
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// display Appropriate Legal Notices, as required under Section 5 of the GNU AGPL version 3.
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//
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// Pursuant to Section 7(b) of the License you must retain the original Product logo when
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// distributing the program. Pursuant to Section 7(e) we decline to grant you any rights under
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// trademark law for use of our trademarks.
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//
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// All the Product's GUI elements, including illustrations and icon sets, as well as technical writing
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// content are licensed under the terms of the Creative Commons Attribution-ShareAlike 4.0
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// International. See the License terms at http://creativecommons.org/licenses/by-sa/4.0/legalcode
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namespace ASC.Common.Utils;
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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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} |