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public class QuotedPrintableConverter
{
private static string _Ascii7BitSigns;
private const string _equalsSign = "=";
private const string _defaultReplaceEqualSign = "=";
/// <summary>
/// Ctor.
/// </summary>
private QuotedPrintableConverter()
{
//do nothing
}
/// <summary>
/// Encodes a not QP-Encoded string.
/// </summary>
/// <param name="value">The string which should be encoded.</param>
/// <returns>The encoded string</returns>
public static string Encode(string value)
{
return Encode(value, _defaultReplaceEqualSign);
}
/// <summary>
/// Encodes a not QP-Encoded string.
/// </summary>
/// <param name="value">The string which should be encoded.</param>
/// <param name="replaceEqualSign">The sign which should replace the "="-sign in front of
/// each QP-encoded sign.</param>
/// <returns>The encoded string</returns>
public static string Encode(string value, string replaceEqualSign)
{
//Alle nicht im Ascii-Zeichnsatz enthaltenen Zeichen werden ersetzt durch die hexadezimale
//Darstellung mit einem vorangestellten =
//Bsp.: aus "ü" wird "=FC"
//Bsp. mit Ersetzungszeichen "%"für das "=": aus "ü" wird "%FC"
GetAllowedAsciiSigns();
StringBuilder sb = new StringBuilder();
foreach (char s in value)
{
if (_Ascii7BitSigns.LastIndexOf(s) > -1)
sb.Append(s);
else
{
string qp = string.Format("{0}{1}",
_equalsSign,
System.Convert.ToString(s, 16)).Replace(_equalsSign, replaceEqualSign);
sb.Append(qp);
}
}
return sb.ToString();
}
/// <summary>
/// Gets a string which contains the first 128-characters (ANSII 7 bit).
/// </summary>
private static void GetAllowedAsciiSigns()
{
StringBuilder sb = new StringBuilder();
for (int i = 0; i < 127; i++)
{
sb.Append(System.Convert.ToChar(i));
}
_Ascii7BitSigns = sb.ToString();
}
}
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