47 lines
1.4 KiB
C#
47 lines
1.4 KiB
C#
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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} |