internal static string DtmfNormalize(string s)
{
if (string.IsNullOrEmpty(s))
{
return(s);
}
StringBuilder stringBuilder = new StringBuilder(s.Length);
foreach (char c in s)
{
if (char.IsLetterOrDigit(c) || char.IsPunctuation(c))
{
stringBuilder.Append(c);
}
}
string text = DtmfString.FoldString(stringBuilder.ToString());
string text2 = text.Normalize(NormalizationForm.FormD);
stringBuilder.Length = 0;
foreach (char c2 in text2)
{
UnicodeCategory unicodeCategory = CharUnicodeInfo.GetUnicodeCategory(c2);
if (unicodeCategory != UnicodeCategory.NonSpacingMark)
{
stringBuilder.Append(DtmfString.NormalizeUsingTable(c2));
}
}
return(stringBuilder.ToString());
}
internal static string DtmfEncode(string s)
{
string text = DtmfString.DtmfNormalize(s);
StringBuilder stringBuilder = new StringBuilder();
foreach (char c in text)
{
char value;
if (DtmfString.GetDtmf(c, out value))
{
stringBuilder.Append(value);
}
}
return(stringBuilder.ToString());
}
private static string FoldString(string input)
{
int num = DtmfString.FoldString(DtmfString.MapFlags.MAP_EXPAND_LIGATURES, input, -1, null, 0);
if (num == 0)
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
StringBuilder stringBuilder = new StringBuilder(num);
if (DtmfString.FoldString(DtmfString.MapFlags.MAP_EXPAND_LIGATURES, input, -1, stringBuilder, num) == 0)
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
return(stringBuilder.ToString());
}