Code:
/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Net / System / Net / Mail / QEncodedStream.cs / 1305376 / QEncodedStream.cs
////// This stream performs in-place decoding of quoted-printable /// encoded streams used in headers. Encoding requires copying into a separate /// buffer as the data being encoded will most likely grow. /// Encoding and decoding is done transparently to the caller. /// this class is meant to be used when RFC 2047 quoted stream encoding ///is needed. This is for headers such as subject and should NOT be ///used for email body /// //------------------------------------------------------------------------------ //// Copyright (c) Microsoft Corporation. All rights reserved. // //----------------------------------------------------------------------------- namespace System.Net.Mime { using System; using System.IO; using System.Text; ////// This stream performs in-place decoding of quoted-printable /// encoded streams. Encoding requires copying into a separate /// buffer as the data being encoded will most likely grow. /// Encoding and decoding is done transparently to the caller. /// internal class QEncodedStream : DelegatedStream, IEncodableStream { //folding takes up 5 characters const int sizeOfFoldingCRLF = 5; //it takes six chars to encode a CRLF const int sizeOfEncodedCRLF = 6; //it takes three chars to encode a non-ascii character const int sizeOfEncodedChar = 3; static byte[] hexDecodeMap = new byte[] {// 0 1 2 3 4 5 6 7 8 9 A B C D E F 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255, // 0 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255, // 1 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255, // 2 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,255,255,255,255,255,255, // 3 255, 10, 11, 12, 13, 14, 15,255,255,255,255,255,255,255,255,255, // 4 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255, // 5 255, 10, 11, 12, 13, 14, 15,255,255,255,255,255,255,255,255,255, // 6 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255, // 7 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255, // 8 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255, // 9 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255, // A 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255, // B 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255, // C 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255, // D 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255, // E 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255, // F }; //bytes that correspond to the hex char representations in ASCII (0-9, A-F) static byte[] hexEncodeMap = new byte[] { 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70 }; int lineLength; ReadStateInfo readState; QuotedStringWriteStateInfo writeState; ////// ctor. /// /// Underlying stream /// Preferred maximum line-length for writes internal QEncodedStream(Stream stream, int lineLength) : base(stream) { if (lineLength < 0) throw new ArgumentOutOfRangeException("lineLength"); this.lineLength = lineLength; } internal QEncodedStream(Stream stream) : this(stream, EncodedStreamFactory.DefaultMaxLineLength) { } internal QEncodedStream(QuotedStringWriteStateInfo wsi) { this.lineLength = EncodedStreamFactory.DefaultMaxLineLength; this.writeState = wsi; } internal QEncodedStream(int lineLength) { this.lineLength = lineLength; } ReadStateInfo ReadState { get { if (this.readState == null) this.readState = new ReadStateInfo(); return this.readState; } } internal WriteStateInfoBase WriteState { get { if (this.writeState == null) this.writeState = new QuotedStringWriteStateInfo(1024, null, null, 76); return this.writeState; } } public override IAsyncResult BeginWrite(byte[] buffer, int offset, int count, AsyncCallback callback, object state) { if (buffer == null) throw new ArgumentNullException("buffer"); if (offset < 0 || offset > buffer.Length) throw new ArgumentOutOfRangeException("offset"); if (offset + count > buffer.Length) throw new ArgumentOutOfRangeException("count"); WriteAsyncResult result = new WriteAsyncResult(this, buffer, offset, count, callback, state); result.Write(); return result; } public override void Close() { FlushInternal(); base.Close(); } public int DecodeBytes(byte[] buffer, int offset, int count) { unsafe { fixed (byte* pBuffer = buffer) { byte* start = pBuffer + offset; byte* source = start; byte* dest = start; byte* end = start + count; // if the last read ended in a partially decoded // sequence, pick up where we left off. if (ReadState.IsEscaped) { // this will be -1 if the previous read ended // with an escape character. if (ReadState.Byte == -1) { // if we only read one byte from the underlying // stream, we'll need to save the byte and // ask for more. if (count == 1) { ReadState.Byte = *source; return 0; } // '=\r\n' means a soft (aka. invisible) CRLF sequence... if (source[0] != '\r' || source[1] != '\n') { byte b1 = hexDecodeMap[source[0]]; byte b2 = hexDecodeMap[source[1]]; if (b1 == 255) throw new FormatException(SR.GetString(SR.InvalidHexDigit, b1)); if (b2 == 255) throw new FormatException(SR.GetString(SR.InvalidHexDigit, b2)); *dest++ = (byte)((b1 << 4) + b2); } source += 2; } else { // '=\r\n' means a soft (aka. invisible) CRLF sequence... if (ReadState.Byte != '\r' || *source != '\n') { byte b1 = hexDecodeMap[ReadState.Byte]; byte b2 = hexDecodeMap[*source]; if (b1 == 255) throw new FormatException(SR.GetString(SR.InvalidHexDigit, b1)); if (b2 == 255) throw new FormatException(SR.GetString(SR.InvalidHexDigit, b2)); *dest++ = (byte)((b1 << 4) + b2); } source++; } // reset state for next read. ReadState.IsEscaped = false; ReadState.Byte = -1; } // Here's where most of the decoding takes place. // We'll loop around until we've inspected all the // bytes read. while (source < end) { // if the source is not an escape character, then // just copy as-is. if (*source != '=') { if (*source == '_') { *dest++ = (byte)' '; source++; } else { *dest++ = *source++; } } else { // determine where we are relative to the end // of the data. If we don't have enough data to // decode the escape sequence, save off what we // have and continue the decoding in the next // read. Otherwise, decode the data and copy // into dest. switch (end - source) { case 2: ReadState.Byte = source[1]; goto case 1; case 1: ReadState.IsEscaped = true; goto EndWhile; default: if (source[1] != '\r' || source[2] != '\n') { byte b1 = hexDecodeMap[source[1]]; byte b2 = hexDecodeMap[source[2]]; if (b1 == 255) throw new FormatException(SR.GetString(SR.InvalidHexDigit, b1)); if (b2 == 255) throw new FormatException(SR.GetString(SR.InvalidHexDigit, b2)); *dest++ = (byte)((b1 << 4) + b2); } source += 3; break; } } } EndWhile: count = (int)(dest - start); } } return count; } public int EncodeBytes(byte[] buffer, int offset, int count) { writeState.CurrentLineLength += writeState.HeaderLength + writeState.MimeHeaderLength; //add the header initially writeState.AppendHeader(); int cur = offset; for (; cur < count + offset; cur++) { //only fold if we're before a whitespace or if it's too long to keep writing if (lineLength != -1 && (WriteState.CurrentLineLength + sizeOfFoldingCRLF >= this.lineLength && (buffer[cur] == ' ' || buffer[cur] == '\t' || buffer[cur] == '\r' || buffer[cur] == '\n')) || WriteState.CurrentLineLength + writeState.FooterLength >= lineLength ) { if (WriteState.Buffer.Length - WriteState.Length < WriteState.FooterLength) WriteState.ResizeBuffer(); WriteState.AppendFooter(); WriteState.Buffer[WriteState.Length++] = (byte)'\r'; WriteState.Buffer[WriteState.Length++] = (byte)'\n'; WriteState.Buffer[WriteState.Length++] = (byte)' '; WriteState.AppendHeader(); WriteState.CurrentLineLength = WriteState.HeaderLength; } //need to dot stuff - rfc 2821 4.5.2 Transparency if (WriteState.CurrentLineLength == 0 && buffer[cur] == '.') { WriteState.Buffer[WriteState.Length++] = (byte)'.'; } //always encode CRLF if (buffer[cur] == '\r' && cur + 1 < count + offset && buffer[cur + 1] == '\n') { //six bytes to encode CRLF needed if (WriteState.Buffer.Length - WriteState.Length < sizeOfEncodedCRLF) WriteState.ResizeBuffer(); cur++; //the encoding for CRLF is =0D=0A WriteState.Buffer[WriteState.Length++] = (byte)'='; WriteState.Buffer[WriteState.Length++] = (byte)'0'; WriteState.Buffer[WriteState.Length++] = (byte)'D'; WriteState.Buffer[WriteState.Length++] = (byte)'='; WriteState.Buffer[WriteState.Length++] = (byte)'0'; WriteState.Buffer[WriteState.Length++] = (byte)'A'; WriteState.CurrentLineLength += sizeOfEncodedCRLF; } else if ((buffer[cur] < 32 && buffer[cur] != '\t') || buffer[cur] == '=' || buffer[cur] > 126) { if (WriteState.Buffer.Length - WriteState.Length < sizeOfEncodedChar) WriteState.ResizeBuffer(); WriteState.CurrentLineLength += sizeOfEncodedChar; //append an = to indicate an encoded character WriteState.Buffer[WriteState.Length++] = (byte)'='; //shift 4 to get the first four bytes only and look up the hex digit WriteState.Buffer[WriteState.Length++] = hexEncodeMap[buffer[cur] >> 4]; //clear the first four bytes to get the last four and look up the hex digit WriteState.Buffer[WriteState.Length++] = hexEncodeMap[buffer[cur] & 0xF]; } else if (buffer[cur] == ' ') { if (WriteState.Buffer.Length - WriteState.Length < 1) WriteState.ResizeBuffer(); //spaces should be escaped as either '_' or '=20' and //we have chosen '_' for parity with other email client //behavior WriteState.CurrentLineLength++; WriteState.Buffer[WriteState.Length++] = (byte)'_'; } else { if (WriteState.Buffer.Length - WriteState.Length < 1) WriteState.ResizeBuffer(); WriteState.CurrentLineLength++; WriteState.Buffer[WriteState.Length++] = buffer[cur]; } } WriteState.AppendFooter(); return cur - offset; } public Stream GetStream() { return this; } public string GetEncodedString() { return ASCIIEncoding.ASCII.GetString(this.WriteState.Buffer, 0, this.WriteState.Length); } public override void EndWrite(IAsyncResult asyncResult) { WriteAsyncResult.End(asyncResult); } public override void Flush() { FlushInternal(); base.Flush(); } void FlushInternal() { if (this.writeState != null && this.writeState.Length > 0) { base.Write(WriteState.Buffer, 0, WriteState.Length); WriteState.Length = 0; } } public override void Write(byte[] buffer, int offset, int count) { if (buffer == null) throw new ArgumentNullException("buffer"); if (offset < 0 || offset > buffer.Length) throw new ArgumentOutOfRangeException("offset"); if (offset + count > buffer.Length) throw new ArgumentOutOfRangeException("count"); int written = 0; for (; ; ) { written += EncodeBytes(buffer, offset + written, count - written); if (written < count) FlushInternal(); else break; } } class ReadStateInfo { bool isEscaped = false; short b1 = -1; internal bool IsEscaped { get { return this.isEscaped; } set { this.isEscaped = value; } } internal short Byte { get { return this.b1; } set { this.b1 = value; } } } class WriteAsyncResult : LazyAsyncResult { QEncodedStream parent; byte[] buffer; int offset; int count; static AsyncCallback onWrite = new AsyncCallback(OnWrite); int written; internal WriteAsyncResult(QEncodedStream parent, byte[] buffer, int offset, int count, AsyncCallback callback, object state) : base(null, state, callback) { this.parent = parent; this.buffer = buffer; this.offset = offset; this.count = count; } void CompleteWrite(IAsyncResult result) { this.parent.BaseStream.EndWrite(result); this.parent.WriteState.Length = 0; } internal static void End(IAsyncResult result) { WriteAsyncResult thisPtr = (WriteAsyncResult)result; thisPtr.InternalWaitForCompletion(); System.Diagnostics.Debug.Assert(thisPtr.written == thisPtr.count); } static void OnWrite(IAsyncResult result) { if (!result.CompletedSynchronously) { WriteAsyncResult thisPtr = (WriteAsyncResult)result.AsyncState; try { thisPtr.CompleteWrite(result); thisPtr.Write(); } catch (Exception e) { thisPtr.InvokeCallback(e); } } } internal void Write() { for (; ; ) { this.written += this.parent.EncodeBytes(this.buffer, this.offset + this.written, this.count - this.written); if (this.written < this.count) { IAsyncResult result = this.parent.BaseStream.BeginWrite(this.parent.WriteState.Buffer, 0, this.parent.WriteState.Length, onWrite, this); if (!result.CompletedSynchronously) break; CompleteWrite(result); } else { InvokeCallback(); break; } } } } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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