C# Quoted-Printable编码、解码

# using system;
# using system.collections;
# using system.text;
#
# /// <summary>
# /// class for encoding and decoding a string to quotedprintable
# /// rfc 1521 http://www.ietf.org/rfc/rfc1521.txt
# /// rfc 2045 http://www.ietf.org/rfc/rfc2045.txt
# /// date: 2006-03-23
# /// author: kevin spaun
# /// company: spaun informationstechnik gmbh - http://www.spaun-it.com/
# /// feedback: [e-mail]
# /// license: this piece of code comes with no guaranties. you can use it for whatever you want for free.
# ///
# /// modified by will huang ( http://blog.miniasp.com/post/2008/02/14/quoted-printable-encoding-and-decoding.aspx )
# /// modified at 2008-02-13
# ///
# /// modified by reterry (//www.jb51.net)
# /// modified at 2008-11-29
# /// modified for myself
# ///
# /// </summary>
# public class quotedprintable
# {
# private const byte equals = 61;
# private const byte cr = 13;
# private const byte lf = 10;
# private const byte space = 32;
# private const byte tab = 9;
#
# /// <summary>
# /// encodes a string to quotedprintable
# /// </summary>
# /// <param name="_toencode">string to encode</param>
# /// <returns>quotedprintable encoded string</returns>
# public static string encode(string _toencode)
# {
# stringbuilder encoded = new stringbuilder();
# string hex = string.empty;
# //byte[] bytes = encoding.default.getbytes(_toencode);
# byte[] bytes = encoding.utf8.getbytes(_toencode);
# //int count = 0;
#
# for (int i = 0; i < bytes.length; i++)
# {
# //these characters must be encoded
# if ((bytes[i] < 33 || bytes[i] > 126 || bytes[i] == equals) && bytes[i] != cr && bytes[i] != lf && bytes[i] != space)
# {
# if (bytes[i].tostring("x").length < 2)
# {
# hex = "0" + bytes[i].tostring("x");
# encoded.append("=" + hex);
# }
# else
# {
# hex = bytes[i].tostring("x");
# encoded.append("=" + hex);
# }
# }
# else
# {
# //check if index out of range
# if ((i + 1) < bytes.length)
# {
# //if tab is at the end of the line - encode it!
# if ((bytes[i] == tab && bytes[i + 1] == lf) || (bytes[i] == tab && bytes[i + 1] == cr))
# {
# encoded.append("=0" + bytes[i].tostring("x"));
# }
# //if space is at the end of the line - encode it!
# else if ((bytes[i] == space && bytes[i + 1] == lf) || (bytes[i] == space && bytes[i + 1] == cr))
# {
# encoded.append("=" + bytes[i].tostring("x"));
# }
# else
# {
# encoded.append(system.convert.tochar(bytes[i]));
# }
# }
# else
# {
# encoded.append(system.convert.tochar(bytes[i]));
# }
# }
# //if (count == 75)
# //{
# // encoded.append("=\r\n"); //insert soft-linebreak
# // count = 0;
# //}
# //count++;
# }
#
# return encoded.tostring();
# }
#
# /// <summary>
# /// decodes a quotedprintable encoded string
# /// </summary>
# /// <param name="_todecode">the encoded string to decode</param>
# /// <returns>decoded string</returns>
# public static string decode(string _todecode)
# {
# //remove soft-linebreaks first
# //_todecode = _todecode.replace("=\r\n", "");
#
# char[] chars = _todecode.tochararray();
#
# byte[] bytes = new byte[chars.length];
#
# int bytescount = 0;
#
# for (int i = 0; i < chars.length; i++)
# {
# // if encoded character found decode it
# if (chars[i] == '=')
# {
# bytes[bytescount++] = system.convert.tobyte(int.parse(chars[i + 1].tostring() + chars[i + 2].tostring(), system.globalization.numberstyles.hexnumber));
#
# i += 2;
# }
# else
# {
# bytes[bytescount++] = system.convert.tobyte(chars[i]);
# }
# }
#
# //return system.text.encoding.default.getstring(bytes, 0, bytescount);
# return system.text.encoding.utf8.getstring(bytes, 0, bytescount);
# }
# }