Qt code having in so many lib zlib compression
On very networkmodule
and on class QZipStreamStrategy : public QOutputStrategy
&& on qtextodfwriter.cpp QTextOdfWriter odt format file..

now Why QSslSocket no?


Qt Code: 
  1. // From qtsdk-2010.05/qt/src/network/access/qhttpnetworkreply_p.h
  2. static const unsigned char gz_magic[2] = {0x1f, 0x8b}; // gzip magic header
  3.     // gzip flag byte
  4. #define HEAD_CRC     0x02 // bit 1 set: header CRC present
  5. #define EXTRA_FIELD  0x04 // bit 2 set: extra field present
  6. #define ORIG_NAME    0x08 // bit 3 set: original file name present
  7. #define COMMENT      0x10 // bit 4 set: file comment present
  8. #define RESERVED     0xE0 // bits 5..7: reserved
  9. #define CHUNK 16384
  10.  
  11. // From qtsdk-2010.05/qt/src/network/access/qhttpnetworkreply.cpp
  12. // && bool ClientParser::gzipCheckHeader(QByteArray &content, int &pos)  same file 
  13. ///  bool ClientParser::gzipCheckHeader(QByteArray &content, int &pos)
  14.  
  15. void ClientHandler::compressResponse(const QByteArray& uncompressed, QByteArray& deflated )
  16. {
  17.     deflated = qCompress(uncompressed);
  18.  
  19.     // eliminate qCompress size on first 4 bytes and 2 byte header
  20.     deflated = deflated.right(deflated.size() - 6);
  21.     // remove qCompress 4 byte footer
  22.     deflated = deflated.left(deflated.size() - 4);
  23.  
  24.     QByteArray header;
  25.     header.resize(10);
  26.     header[0] = 0x1f; // gzip-magic[0]
  27.     header[1] = 0x8b; // gzip-magic[1]
  28.     header[2] = 0x08; // Compression method = DEFLATE
  29.     header[3] = 0x00; // Flags
  30.     header[4] = 0x00; // 4-7 is mtime
  31.     header[5] = 0x00;
  32.     header[6] = 0x00;
  33.     header[7] = 0x00;
  34.     header[8] = 0x00; // XFL
  35.     header[9] = 0x03; // OS=Unix
  36.  
  37.     deflated.prepend(header);
  38.  
  39.     QByteArray footer;
  40.     quint32 crc = crc32(0L, Z_NULL, 0);
  41.     crc = crc32(crc, (const uchar*)uncompressed.data(), uncompressed.size());
  42.     footer.resize(8);
  43.     footer[3] = (crc & 0xff000000) >> 24;
  44.     footer[2] = (crc & 0x00ff0000) >> 16;
  45.     footer[1] = (crc & 0x0000ff00) >> 8;
  46.     footer[0] = (crc & 0x000000ff);
  47.  
  48.     quint32 isize = uncompressed.size();
  49.     footer[7] = (isize & 0xff000000) >> 24;
  50.     footer[6] = (isize & 0x00ff0000) >> 16;
  51.     footer[5] = (isize & 0x0000ff00) >> 8;
  52.     footer[4] = (isize & 0x000000ff);
  53.  
  54.     deflated.append(footer);
  55. }
To copy to clipboard, switch view to plain text mode 

I ned for imap big mail attachment over socket...
here standard http://www.ietf.org/rfc/rfc4978.txt

The following example illustrates how commands and responses are
compressed during a simple login sequence:

S: * OK [CAPABILITY IMAP4REV1 STARTTLS COMPRESS=DEFLATE]
C: a starttls
S: a OK TLS active

From this point on, everything is encrypted.

C: b login arnt pass27385621
S: b OK Logged in as arnt
C: c compress deflate
S: d OK DEFLATE active

From this point on, everything is compressed before being
encrypted.
now i muss subclass QSslSocket to having inside 20 line code to decompress chunk mail code...
i see on trojita mail client imap defalte ... over 1000 line class Socket subclass to having this 20 line uncompress this is like drugs..
:-( ...
http://trojita.flaska.net/

Note before encrypted!! is on deflate algoritmus... and now how i read this chunk? zlib encrypted.. this is very hot..
sorry my grammar english i like all latino language...
regards...