Несмотря на то, что он не защищен от ошибок и все еще находится в стадии разработки, вот несколько методов расширения, которые мы создали для преобразования символов в ASCII из UTF.
public static class UnicodeToAsciiConverter
{
#region Mappings
/// <summary>
/// A string-to-string dictionary for mapping unicode text element keys to their
/// equivalent ASCII text element values.
/// </summary>
private static readonly IDictionary<string, string> UnicodeToAsciiConversions = new Dictionary<string, string>
{
{ "ʼ", SingleQuote }, { "‘", SingleQuote }, { "’", SingleQuote }, { "ʻ", SingleQuote }, { "–", "-" },
{ "", string.Empty }, { "¯", "_"}, { "—", "-"},
{ "á", a }, { "Á", A }, { "à", a }, { "À", A }, { "â", a }, { "Â", A }, { "ä", a }, { "Ä", A },
{ "ă", a }, { "Ă", A }, { "ā", a }, { "Ā", A }, { "ã", a }, { "Ã", A }, { "å", a }, { "Å", A },
{ "ầ", a }, { "Ầ", A }, { "ắ", a }, { "Ắ", A }, { "ằ", a }, { "Ằ", A }, { "ẵ", a }, { "Ẵ", A },
{ "ả", a }, { "Ả", A }, { "ạ", a }, { "Ạ", A }, { "ậ", a }, { "Ậ", A }, { "ấ", a }, { "Ấ", A },
{ "ą", a }, { "Ą", A },
{ "æ", "ae" }, { "Æ", "AE" }, { "ǣ", "ae" }, { "Ǣ", "AE" },
{ "ß", b }, { "þ", b }, { "Þ", B },
{ "ć", c }, { "Ć", C }, { "č", c }, { "Č", C }, { "ç", c }, { "Ç", C }, { "ĉ", c }, { "Ĉ", C },
{ "ċ", c }, { "Ċ", C },
{ "ḑ", d }, { "Ḑ", D }, { "đ", d }, { "Đ", D }, { "ð", d }, { "Ð", D }, { "ḍ", d }, { "Ḍ", D },
{ "ď", d }, { "Ď", D }, { "ḑ", d }, { "Ḑ", D },
{ "é", e }, { "É", E }, { "è", e }, { "È", E }, { "ė", e }, { "Ė", E }, { "ê", e }, { "Ê", E },
{ "ë", e }, { "Ë", E }, { "ě", e }, { "Ě", E }, { "ĕ", e }, { "Ĕ", E }, { "ē", e }, { "Ē", E },
{ "ę", e }, { "Ę", E }, { "ế", e }, { "Ế", E }, { "ề", e }, { "Ề", E }, { "ệ", e }, { "Ệ", E },
{ "ǝ", e }, { "Ǝ", E }, { "ə", e }, { "Ə", E }, { "ể", e }, { "Ể", E }, { "ễ", e }, { "Ễ", E },
{ "ẹ̀", e }, { "Ẹ̀", E }, { "ɛ́", e }, { "ɛ", e }, { "Ɛ", E },
{ "ğ", g }, { "Ğ", G }, { "ĝ", g }, { "Ĝ", G }, { "ġ", g }, { "Ġ", G }, { "ģ", g }, { "Ģ", G },
{ "ḩ", h }, { "Ḩ", H }, { "ħ", h }, { "Ħ", H }, { "ḥ", h }, { "Ḥ", H }, { "ĥ", h }, { "Ĥ", H },
{ "ẖ", h }, { "H̱", H }, { "h̲", h }, { "H̲", H }, { "ḩ", h }, { "Ḩ", H },
{ "ı", i }, { "ı".ToUpper(), I }, { "í", i }, { "Í", I }, { "ì", i }, { "Ì", I }, { "İ".ToLower(), i }, { "İ", I },
{ "î", i }, { "Î", I }, { "ï", i }, { "Ï", I }, { "ĭ", i }, { "Ĭ", I }, { "ī", i }, { "Ī", I },
{ "ĩ", i }, { "Ĩ", I }, { "ỉ", i }, { "Ỉ", I }, { "ị", i }, { "Ị", I },
{ "ķ", k }, { "Ķ", K },
{ "ļ", l }, { "Ļ", L }, { "ł", l }, { "Ł", L }, { "ľ", l }, { "Ľ", L },
{ "ň", n }, { "Ň", N }, { "ñ", n }, { "Ñ", N }, { "ń", n }, { "Ń", N }, { "ŋ", n }, { "Ŋ", N },
{ "ņ", n }, { "Ņ", N },
{ "ó", o }, { "Ó", O }, { "ò", o }, { "Ò", O }, { "ô", o }, { "Ô", O }, { "ö", o }, { "Ö", O },
{ "ŏ", o }, { "Ŏ", O }, { "ō", o }, { "Ō", O }, { "õ", o }, { "Õ", O }, { "ő", o }, { "Ő", O },
{ "ố", o }, { "Ố", O }, { "ồ", o }, { "Ồ", O }, { "ø", o }, { "Ø", O }, { "ơ", o }, { "Ơ", O },
{ "ọ", o }, { "Ọ", O }, { "ớ", o }, { "Ớ", O }, { "ộ", o }, { "Ộ", O }, { "ɔ", o }, { "Ɔ", O },
{ "ɔ́", o }, { "Ɔ́", O }, { "ổ", o }, { "Ổ", O }, { "ỏ", o }, { "Ỏ", O },
{ "œ", oe }, { "Œ", OE }, { "œ̆", oe }, { "Œ̆", OE },
{ "ř", r }, { "Ř", R },
{ "ś", s }, { "Ś", S }, { "š", s }, { "Š", S }, { "ş", s }, { "Ş", S }, { "ṣ", s }, { "Ṣ", S },
{ "ŝ", s }, { "Ŝ", S }, { "ș", s }, { "s̲", s }, { "S̲", S },
{ "ţ", t }, { "Ţ", T }, { "ṭ", t }, { "Ṭ", T }, { "ŧ", t }, { "Ŧ", T }, { "ț", t }, { "ť", t }, { "Ť", T },
{ "ú", u }, { "Ú", U }, { "ù", u }, { "Ù", U }, { "ü", u }, { "Ü", U }, { "ŭ", u }, { "Ŭ", U },
{ "ū", u }, { "Ū", U }, { "ũ", u }, { "Ũ", U }, { "ų", u }, { "Ų", U }, { "ủ", u }, { "Ủ", U },
{ "ư", u }, { "Ư", U }, { "ừ", u }, { "Ừ", U }, { "û", u }, { "Û", U }, { "ự", u }, { "Ự", U },
{ "ů", u }, { "Ů", U }, { "ụ", u }, { "Ụ", U }, { "ṳ", u }, { "Ṳ", U }, { "ứ", u }, { "Ứ", U },
{ "ŵ", w }, { "Ŵ", W },
{ "ý", y }, { "Ý", Y }, { "ỹ", y }, { "Ỹ", Y }, { "ỳ", y }, { "Ỳ", Y },
{ "ź", z }, { "Ź", Z }, { "ž", z }, { "Ž", Z }, { "z̄", z }, { "Z̄", Z }, { "z̧", z }, { "Z̧", Z },
{ "ż", z }, { "Ż", Z }, { "ẕ", z }, { "Ẕ", Z },
};
#region ASCII Constants
// ReSharper disable InconsistentNaming
// ascii constants save memory for immutable strings
private const string SingleQuote = "'";
private const string a = "a";
private const string A = "A";
private const string b = "b";
private const string B = "B";
private const string c = "c";
private const string C = "C";
private const string d = "d";
private const string D = "D";
private const string e = "e";
private const string E = "E";
private const string g = "g";
private const string G = "G";
private const string h = "h";
private const string H = "H";
private const string i = "i";
private const string I = "I";
private const string k = "k";
private const string K = "K";
private const string l = "l";
private const string L = "L";
private const string n = "n";
private const string N = "N";
private const string o = "o";
private const string O = "O";
private const string oe = "oe";
private const string OE = "OE";
private const string r = "r";
private const string R = "R";
private const string s = "s";
private const string S = "S";
private const string t = "t";
private const string T = "T";
private const string u = "u";
private const string U = "U";
private const string w = "w";
private const string W = "W";
private const string y = "y";
private const string Y = "Y";
private const string z = "z";
private const string Z = "Z";
// ReSharper restore InconsistentNaming
#endregion
#endregion
#region Conversion
/// <summary>
/// Converts unicode text to its ASCII equivalent using a 2-pass algorithm.
/// <para>
/// In the first pass, the <paramref name="unicodeText"/> parameter is searched
/// for text present in the <see cref="UnicodeToAsciiConversions"/> dictionary.
/// For each match, the unicode text is replaced with its equivalent ASCII text
/// from the dictionary. <em>It cannot be guaranteed that each non-ASCII character
/// will be converted after the first pass.</em>
/// </para>
/// <para>
/// The second pass guarantees that the converted text will be ASCII-compatible.
/// This is achieved by replacing all incompatible charaters with a question mark
/// (?) character.
/// </para>
/// </summary>
/// <param name="unicodeText">
/// The unicode text to convert to an ASCII equivalent.
/// </param>
/// <returns>
/// The ASCII equivalent of the <paramref name="unicodeText"/> value.
/// </returns>
private static string Convert(string unicodeText)
{
if (string.IsNullOrWhiteSpace(unicodeText))
return unicodeText;
var asciiBuilder = new StringBuilder(unicodeText);
foreach (var conversion in UnicodeToAsciiConversions)
{
if (unicodeText.Contains(conversion.Key))
{
asciiBuilder.Replace(conversion.Key, conversion.Value);
}
}
asciiBuilder.Replace("·", string.Empty);
asciiBuilder.Replace("", string.Empty);
var utf8Encoding = new UTF8Encoding();
var asciiEncoding = new ASCIIEncoding();
var convertedToAsciiPass1 = asciiBuilder.ToString();
var utfBytes = utf8Encoding.GetBytes(convertedToAsciiPass1);
if (utfBytes.Contains((byte)204) && utfBytes.Contains((byte)129))
{
var utfList = utfBytes.ToList();
while (utfList[utfList.IndexOf(204) + 1] == 129)
{
utfList.RemoveAt(utfList.IndexOf(204) + 1);
utfList.RemoveAt(utfList.IndexOf(204));
}
utfBytes = utfList.ToArray();
}
var asciiBytes = Encoding.Convert(utf8Encoding, asciiEncoding, utfBytes);
var convertedToAsciiPass2 = asciiEncoding.GetString(asciiBytes);
return convertedToAsciiPass2;
}
#endregion
#region String Extension Methods
/// <summary>
/// Converts unicode text to its ASCII equivalent using the
/// <see cref="UnicodeToAsciiConverter.Convert(System.String)"/> implementation.
/// </summary>
/// <remarks>
/// This is simply a shortcut to provide a more fluent API when converting
/// unicode text values to their ASCII equivalents.
/// </remarks>
/// <returns>
/// The ASCII equivalent of the this text value.
/// </returns>
public static string ConvertToAscii(this string unicodeText)
{
return Convert(unicodeText);
}
/// <summary>
/// Determines whether a string of text contains only question marks and
/// whitespace characters. This is useful in determining whether a conversion
/// from unicode to ASCII failed completely, as often happens with languages
/// like Arabic.
/// </summary>
/// <returns>
/// <code>True</code> if this string of text contains only question marks and whitespace
/// characters, otherwise <code>false</code>.
/// </returns>
public static bool ContainsOnlyQuestionMarksAndWhiteSpace(this string text)
{
return text.All(character => character == '?' || character == ' ' || character == '\''
|| character == '-' || character == '_' || character == '(' || character == ')'
|| character == ',' || character == '/' || character == '.' || character == '&'
|| character == '"');
}
#endregion
}