using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

​

namespace StringBuilderToUTF8

{

​

    public static class StringExtensions

    {

        //set for UTF-8 encoding, no errors

        private static readonly Encoding Utf8Encoder = UTF8Encoding.GetEncoding("UTF-8", new EncoderReplacementFallback(string.Empty), new DecoderExceptionFallback());

        private static readonly Encoding Utf16Encoder = UTF8Encoding.GetEncoding("UTF-16", new EncoderReplacementFallback(string.Empty), new DecoderExceptionFallback());

        private static readonly Encoding ISO88591Encoder = UTF8Encoding.GetEncoding("ISO-8859-1", new EncoderReplacementFallback(string.Empty), new DecoderExceptionFallback());

        public static string toUTF8String(this StringBuilder sb) //incomming string is UTF-16

        {

​

            byte[] bytesUTF16 = Utf16Encoder.GetBytes(sb.ToString());

            char[] charsUTF16 = Utf16Encoder.GetChars(bytesUTF16);

​

            byte[] bytesUTF8 = Utf8Encoder.GetBytes(sb.ToString());

            char[] charsUTF8 = Utf8Encoder.GetChars(bytesUTF8);

​

            byte[] bytesISO88591 = ISO88591Encoder.GetBytes(sb.ToString());

            char[] charsISO88591 = ISO88591Encoder.GetChars(bytesUTF16);

​

​

            byte[] bytes = Encoding.Default.GetBytes(sb.ToString()); //defaults to ANSI string

            char[] chars = Encoding.Default.GetChars(bytes);

​

            //get clean UTF-8 string from stringbuilder char[]  

            //return Utf8Encoder.GetString(Utf8Encoder.GetBytes(charsISO88591));

            //return Utf8Encoder.GetString(ISO88591Encoder..GetBytes(charsISO88591));

​

            //return Encoding.Default.GetString(bytesISO88591, 0, bytesISO88591.Length); 

            //return ISO88591Encoder.GetString(bytesISO88591, 0, bytesISO88591.Length); 

​

            //Get UTF-8 string

            return Utf8Encoder.GetString(bytesUTF8, 0, bytesUTF8.Length); 

        }

​

        public static string toISO88591String(this StringBuilder sb)

        {

​

            byte[] bytesISO88591 = ISO88591Encoder.GetBytes(sb.ToString());

            return ISO88591Encoder.GetString(bytesISO88591, 0, bytesISO88591.Length); 

        }

​

        public static string toUTF8StringFastCopy(this StringBuilder sb)

        {

​

            char[] bytes = new char[sb.Length];

​

            //copies StringBuilder to []

            sb.CopyTo(0, bytes, 0, sb.Length);

​

            //get clean UTF-8 string from stringbuilder char[]  

            return Utf8Encoder.GetString(Utf8Encoder.GetBytes(bytes));

​

        }

​

        // Based on http://www.codeproject.com/Articles/13503/Stripping-Accents-from-Latin-Characters-A-Foray-in

        // Proper Normalization //Wed 08-Feb-23 9:34am metadataconsulting.ca - faster

        public static string UnicodeToANSI(this string s)

        {

            var newStringBuilder = new StringBuilder();

            newStringBuilder.Append(s.Normalize(NormalizationForm.FormKD)

                                    .Where(x => (x > 30 && x <= 255))

                                    .ToArray());

            return newStringBuilder.ToString();

        }

​

​

​

​

    }

    public class Program

    {

        public static void Main(string[] args)

        {

            //Console.OutputEncoding = Encoding.UTF8;

​

            //Search for “𤭢” code point, which is “U+24B62”

            //In case of a code points is over than U+10000, UTF16 encoding requires 2 bytes of 16 bits binary. We have to subtract 0x10000 from the code points. Now the remaining is “14B62”

            //Convert “14B62” to binary numbers.

​

            string utf16 = "Menü \uD852\uDF62 a\u0304\u0308  你好"; //The result of  “𤭢” or “U+24B62” will be 0xD852 0xDF62 or \uD852\uDF62

​

            //combining characters ("a\u0304\u0308" = "ā̈"), and surrogate pairs are interpretted

​

            StringBuilder sb = new StringBuilder(utf16);

​

            Console.WriteLine("Clean UTF8 only = " + utf16);

​

            Console.WriteLine("Clean ISO-8859-1 only = " + sb.toISO88591String());

            Console.WriteLine("Clean UTF8 only = " + sb.toUTF8String());

            Console.WriteLine("Clean UTF8 fast copy = " + sb.toUTF8StringFastCopy());

​

​

        }

    }

}