C# ByteString.Substring方法代码示例

        private static ImapSearchCriteria FromUri(Uri uri,
                                              bool convertLiteral,
                                              bool synchronizedLiteral,
                                              bool splitCharset,
                                              out bool containsLiteral,
                                              out string charset)
        {
            if (uri == null)
            throw new ArgumentNullException("uri");

              containsLiteral = false;
              charset = null;

              var q = uri.Query;

              if (q.Length == 0)
            return null;
              else if (q.Length == 1) // '?'
            return new ImapSearchCriteria(string.Empty);

              /*
               * http://tools.ietf.org/html/rfc5092
               * RFC 5092 - IMAP URL Scheme
               *
               *    Note that quoted strings and non-synchronizing literals [LITERAL+]
               *    are allowed in the <enc-search> content; however, synchronizing
               *    literals are not allowed, as their presence would effectively mean
               *    that the agent interpreting IMAP URLs needs to parse an <enc-search>
               *    content, find all synchronizing literals, and perform proper command
               *    continuation request handling (see Sections 4.3 and 7 of [IMAP4]).
               */
              var query = PercentEncoding.Decode(q.Substring(1), false);
              var len = query.Length;
              var convertedQuery = new ByteStringBuilder(len);

              if (splitCharset) {
            var queryString = new ByteString(query);

            if (queryString.StartsWithIgnoreCase(charsetSpecification)) {
              // CHARSET<SP>astring<SP>
              var posEndOfCharset = queryString.IndexOf(Octets.SP, charsetSpecification.Length);

              if (posEndOfCharset < 0) {
            throw new ArgumentException("search criteria contains invalid charset specification", "uri");
              }
              else {
            charset = queryString.Substring(charsetSpecification.Length,
                                            posEndOfCharset - charsetSpecification.Length).ToString();

            query = queryString.Substring(posEndOfCharset + 1).ByteArray;
            len = query.Length;
              }
            }
              }

              for (var i = 0; i < len;) {
            if (query[i] == ImapOctets.DQuote) {
              /*
               * quoted
               */
              var start = i;

              for (;;) {
            if (++i == len)
              throw new ArgumentException("search criteria contains unclosed quoted string", "uri");

            if (query[i] == ImapOctets.DQuote) {
              break;
            }
            else if (query[i] == ImapOctets.BackSlash) {
              if (++i == len || !(query[i] == ImapOctets.DQuote || query[i] == ImapOctets.BackSlash))
                throw new ArgumentException("search criteria contains invalid quoted string", "uri");
            }
              }

              i++;

              convertedQuery.Append(query, start, i - start);
            }
            else if (query[i] == ImapOctets.OpenBrace) {
              /*
               * literal
               */
              var start = i;
              var isLiteralSynchronizing = false;
              var literalLength = 0;

              for (;;) {
            if (++i == len)
              throw new ArgumentException("search criteria contains incomplete literal", "uri");

            if (Octets.IsDecimalNumber(query[i])) {
              literalLength = literalLength * 10 + (query[i] - 0x30 /* '0' */);
              // TODO: check length
            }
            else if (query[i] == ImapOctets.CloseBrace) {
              // {xxx}
              isLiteralSynchronizing = true;
              break;
            }
//.........这里部分代码省略.........

            private byte[] EncodeCriteria(ImapSearchCriteria criteria)
            {
                Enqueue(new[] {criteria});
                Enqueue(Octets.CRLF);

                Send();

                try {
                  var innerStream = Stream.InnerStream as MemoryStream;

                  innerStream.Close();

                  var ret = new ByteString(innerStream.ToArray());

                  return ret.Substring(0, ret.Length - 2 /*CRLF*/).ByteArray;
                }
                finally {
                  Stream.Close();
                }
            }

        private PopResponseText ParseText(byte[] line, int posStatusEnd)
        {
            /*
               * http://tools.ietf.org/html/rfc2449
               * 3. General Command and Response Grammar
               *       single-line  =  status [SP text] CRLF       ;512 octets maximum
               *       status       =  "+OK" / "-ERR"
               *       text         =  *schar / resp-code *CHAR
               *       resp-code    =  "[" resp-level *("/" resp-level) "]"
               *       resp-level   =  1*rchar
               *       schar        =  %x21-5A / %x5C-7F
               *                           ;printable ASCII, excluding "["
               *       rchar        =  %x21-2E / %x30-5C / %x5E-7F
               *                           ;printable ASCII, excluding "/" and "]"
               */
              if (line.Length - 2 == posStatusEnd)
            return new PopResponseText();

              posStatusEnd++; // SP

              var text = new ByteString(line, posStatusEnd, line.Length - (posStatusEnd + 2/*CRLF*/));

              if (text[0] != PopOctets.OpenBracket)
            return new PopResponseText(null, text);

              var respCodeEnd = text.IndexOf(PopOctets.CloseBracket);

              if (respCodeEnd < 0)
            return new PopResponseText(null, text);
              else
            return new PopResponseText(PopResponseCode.GetKnownOrCreate(text.Substring(1/*'['*/, respCodeEnd - 1).ToString()),
                                   text.Substring(respCodeEnd + 1).TrimStart());
        }

        private static MimeHeaderCollection ParseHeader(LineOrientedStream stream)
        {
            var headers = new MimeHeaderCollection();
              MimeHeader current = null;

              for (;;) {
            var lineBytes = stream.ReadLine(false);

            if (lineBytes == null)
              break; // unexpected end of stream

            var line = new ByteString(lineBytes);

            if (line.IsEmpty)
              break; // end of headers

            if (line[0] == Octets.HT || line[0] == Octets.SP) { // LWSP-char
              // folding
              if (current == null)
            // ignore incorrect formed header
            continue;

              current.Value += Chars.SP;
              current.Value += line.TrimStart().ToString();
            }
            else {
              // field       =  field-name ":" [ field-body ] CRLF
              // field-name  =  1*<any CHAR, excluding CTLs, SPACE, and ":">
              var delim = line.IndexOf(MimeHeader.NameBodyDelimiter); // ':'

              if (delim < 0) {
            // ignore incorrect formed header
            current = null;
            continue;
              }

              var header = new MimeHeader(line.Substring(0, delim).TrimEnd().ToString(),
                                      line.Substring(delim + 1).TrimStart().ToString());

              headers.Add(header);

              current = header;
            }
              }

              return headers;
        }

        private ImapResponseText ParseRespText(ByteString respText)
        {
            // resp-text       = ["[" resp-text-code "]" SP] text
              if (respText[0] != ImapOctets.OpenBracket)
            // no resp-text-code
            return new ImapResponseText(DecodeRespTextString(respText.Substring(0, respText.Length - 2))); // remove trailing CRLF

              // exists resp-text-code
              var respTextCodeEnd = respText.IndexOf(ImapOctets.CloseBracket);
              var respTextCode    = respText.Substring(1, respTextCodeEnd - 1);
              var codeSep         = respTextCode.IndexOf(Octets.SP);

              ByteString text;

              if (respTextCodeEnd < respText.Length) {
            text = respText.Substring(respTextCodeEnd + 1);
            text = text.Trim(); // remove SP, CRLF
              }
              else {
            text = ByteString.CreateEmpty();
              }

              if (codeSep == -1)
            // no arguments; "READ-ONLY" / "READ-WRITE" / etc...
            return new ImapResponseText(ImapResponseCode.GetKnownOrCreate(respTextCode.ToString()),
                                    new ImapData[] {},
                                    DecodeRespTextString(text));

              // exist arguments; "UIDNEXT" SP nz-number / "UIDVALIDITY" SP nz-number / etc...
              var codeString = respTextCode.Substring(0, codeSep);
              var arguments = ParseDataNonTerminatedText(respTextCode, codeSep + 1);

              if (arguments == null)
            throw new ImapMalformedResponseException("malformed resp-text-code", respTextCode.ToString(codeSep + 1));

              return new ImapResponseText(ImapResponseCode.GetKnownOrCreate(codeString.ToString(), arguments[0]),
                                  arguments,
                                  DecodeRespTextString(text));
        }

        private ImapResponse ParseResponce(ByteString line, ref IParsingContext parsingContext)
        {
            // response        = *(continue-req / response-data) response-done

              // continue-req    = "+" SP (resp-text / base64) CRLF
              if (line.StartsWith(continueReqMark))
            return new ImapCommandContinuationRequest(line.ToString(2, line.Length - 4)); // remove leading "+" SP and trailing CRLF

              // greeting        = "*" SP (resp-cond-auth / resp-cond-bye) CRLF
              // response-done   = response-tagged / response-fatal
              // response-data   = "*" SP (resp-cond-state / resp-cond-bye /
              //                   mailbox-data / message-data / capability-data) CRLF
              // response-fatal  = "*" SP resp-cond-bye CRLF
              //                     ; Server closes connection immediately
              // response-tagged = tag SP resp-cond-state CRLF

              // ("*" / tag) SP
              var tagSep = line.IndexOf(Octets.SP);

              if (tagSep == -1)
            // response-done and response-data must contain SP
            throw new ImapMalformedResponseException("malformed response-done/response-data", line.ToString());

              var untagged = (tagSep == 1 && line[0] == ImapOctets.Asterisk);

              // ("OK" / "BAD" / "NO" / "BYE" / "PREAUTH" / text) SP
              var respCondSep = line.IndexOf(Octets.SP, tagSep + 1);
              var cond = ImapResponseCondition.Undefined;

              if (respCondSep == -1) {
            if (!untagged)
              throw new ImapMalformedResponseException("malformed response-data", line.ToString());
            //else
              // '* SEARCH\r\n' (mailbox-data which contains no SP)
              }
              else {
            cond = ParseCondition(line.Substring(tagSep + 1, respCondSep - tagSep - 1));
              }

              if (cond != ImapResponseCondition.Undefined || line.StartsWith(respCondMark)) {
            // resp-cond-auth / resp-cond-state / resp-cond-bye
            var responseText = ParseRespText((cond == ImapResponseCondition.Undefined)
                                           ? line.Substring(tagSep + 1)
                                           : line.Substring(respCondSep + 1));

            if (untagged)
              return new ImapUntaggedStatusResponse((ImapResponseCondition)cond,
                                            responseText);
            else
              return new ImapTaggedStatusResponse(line.ToString(0, tagSep),
                                          (ImapResponseCondition)cond,
                                          responseText);
              }

              // mailbox-data / message-data / capability-data etc.
              return ParseDataResponse(line, ref parsingContext);
        }

        private static Dictionary<string, ByteString> ParseChallenge(ByteString str)
        {
            // quoted-string  = ( <"> qdstr-val <"> )
              // qdstr-val      = *( qdtext | quoted-pair )
              // qdtext         = <any TEXT except <">>
              // quoted-pair    = "\" CHAR
              var splitAt = new List<int>();
              var quoted = false;

              for (var i = 0; i < str.Length; i++) {
            if (str[i] == '\\') // escape
              i++;
            else if (str[i] == '\"')
              quoted = !quoted;
            else if (!quoted && str[i] == ',')
              splitAt.Add(i);
              }

              splitAt.Add(str.Length); // end of line

              var pairs = new ByteString[splitAt.Count];

              for (var i = 0; i < pairs.Length; i++) {
            if (i == 0)
              pairs[i] = str.Substring(0, splitAt[i]).Trim();
            else
              pairs[i] = str.Substring(splitAt[i - 1] + 1, splitAt[i] - splitAt[i - 1] - 1).Trim();
              }

              var ret = new Dictionary<string, ByteString>(StringComparer.Ordinal);

              foreach (var p in Array.ConvertAll(pairs, delegate(ByteString pair) {
            var delim = pair.IndexOf('=');
            var dequote = (pair[delim + 1] == '\"') && pair.EndsWith("\"");

            if (dequote)
              return new KeyValuePair<string, ByteString>(pair.Substring(0, delim).ToString(),
                                                      pair.Substring(delim + 2, pair.Length - (delim + 3)));
            else
              return new KeyValuePair<string, ByteString>(pair.Substring(0, delim).ToString(),
                                                      pair.Substring(delim + 1));
              })) {
            // TODO: quoted-pair
            ret.Add(p.Key, p.Value);
              }

              return ret;
        }

        public void TestSubstring()
        {
            var str = new ByteString("abcde");

              Assert.AreEqual(new ByteString("abcde"), str.Substring(0));
              Assert.AreEqual(new ByteString("abcde"), str.Substring(0, 5));
              Assert.AreEqual(new ByteString("cde"), str.Substring(2));
              Assert.AreEqual(new ByteString("cd"), str.Substring(2, 2));
        }

        public void TestIndexOf()
        {
            var str = new ByteString("ababdabdbdabcab");

              Assert.AreEqual(10, str.IndexOf(new ByteString("abc")));
              Assert.AreEqual("abc", str.Substring(10, 3).ToString());
              Assert.AreEqual(2, str.IndexOf(new ByteString("abd")));
              Assert.AreEqual("abd", str.Substring(2, 3).ToString());
              Assert.AreEqual(-1, str.IndexOf(new ByteString("abe")));

              var substr = new ByteString("ab");

              Assert.AreEqual(0, str.IndexOf(substr));
              Assert.AreEqual(0, str.IndexOf(substr, 0));
              Assert.AreEqual(2, str.IndexOf(substr, 1));
              Assert.AreEqual(2, str.IndexOf(substr, 2));
              Assert.AreEqual(5, str.IndexOf(substr, 3));
              Assert.AreEqual(5, str.IndexOf(substr, 4));
              Assert.AreEqual(5, str.IndexOf(substr, 5));
        }