Best way to shorten UTF8 string based on byte length

Question

A recent project called for importing data into an Oracle database. The program that will do this is a C# .Net 3.5 app and I\'m using the Oracle.DataAccess connection libra

Answer 1

Shorter version of ruffin's answer. Takes advantage of the design of UTF8:

    public static string LimitUtf8ByteCount(this string s, int n)
    {
        // quick test (we probably won't be trimming most of the time)
        if (Encoding.UTF8.GetByteCount(s) <= n)
            return s;
        // get the bytes
        var a = Encoding.UTF8.GetBytes(s);
        // if we are in the middle of a character (highest two bits are 10)
        if (n > 0 && ( a[n]&0xC0 ) == 0x80)
        {
            // remove all bytes whose two highest bits are 10
            // and one more (start of multi-byte sequence - highest bits should be 11)
            while (--n > 0 && ( a[n]&0xC0 ) == 0x80)
                ;
        }
        // convert back to string (with the limit adjusted)
        return Encoding.UTF8.GetString(a, 0, n);
    }