interface/wx/zstream.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        zstream.h
   3 // Purpose:     interface of wxZlibOutputStream
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows license
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9
  10 /// Compression level
  11 enum wxZlibCompressionLevels {
  12     wxZ_DEFAULT_COMPRESSION = -1,
  13     wxZ_NO_COMPRESSION = 0,
  14     wxZ_BEST_SPEED = 1,
  15     wxZ_BEST_COMPRESSION = 9
  16 };
  17
  18 /// Flags
  19 enum wxZLibFlags {
  20     wxZLIB_NO_HEADER = 0,    //!< raw deflate stream, no header or checksum
  21     wxZLIB_ZLIB = 1,         //!< zlib header and checksum
  22     wxZLIB_GZIP = 2,         //!< gzip header and checksum, requires zlib 1.2.1+
  23     wxZLIB_AUTO = 3          //!< autodetect header zlib or gzip
  24 };
  25
  26
  27 /**
  28     @class wxZlibOutputStream
  29
  30     This stream compresses all data written to it.
  31
  32     The compressed output can be in zlib or gzip format.
  33     Note that writing the gzip format requires zlib version 1.2.1 or greater
  34     (the builtin version does support gzip format).
  35
  36     The stream is not seekable, wxOutputStream::SeekO() returns
  37     ::wxInvalidOffset.
  38
  39     @library{wxbase}
  40     @category{archive,streams}
  41
  42     @see wxOutputStream, wxZlibInputStream
  43 */
  44 class wxZlibOutputStream : public wxFilterOutputStream
  45 {
  46 public:
  47     //@{
  48     /**
  49         Creates a new write-only compressed stream.
  50
  51         @a level means level of compression. It is number between 0 and 9
  52         (including these values) where 0 means no compression and 9 best but
  53         slowest compression. -1 is default value (currently equivalent to 6).
  54
  55         If the parent stream is passed as a pointer then the new filter stream
  56         takes ownership of it. If it is passed by reference then it does not.
  57
  58         The @a flags wxZLIB_ZLIB and wxZLIB_GZIP specify whether the output data
  59         will be in zlib or gzip format. wxZLIB_ZLIB is the default.
  60
  61         If @a flags is wxZLIB_NO_HEADER, then a raw deflate stream is output
  62         without either zlib or gzip headers. This is a lower level mode, which
  63         is not usually used directly. It can be used to embed a raw deflate
  64         stream in a higher level protocol.
  65
  66         The values of the ::wxZlibCompressionLevels and ::wxZLibFlags
  67         enumerations can be used.
  68     */
  69     wxZlibOutputStream(wxOutputStream& stream, int level = -1,
  70                        int flags = wxZLIB_ZLIB);
  71     wxZlibOutputStream(wxOutputStream* stream, int level = -1,
  72                        int flags = wxZLIB_ZLIB);
  73     //@}
  74
  75     /**
  76         Returns @true if zlib library in use can handle gzip compressed data.
  77     */
  78     static bool CanHandleGZip();
  79
  80     //@{
  81     /**
  82         Sets the dictionary to the specified chunk of data. This can improve
  83         compression rate but note that the dictionary has to be the same when
  84         you deflate the data as when you inflate the data, otherwise you
  85         will inflate corrupted data.
  86
  87         Returns @true if the dictionary was successfully set.
  88     */
  89     bool SetDictionary(const char *data, const size_t datalen);
  90     bool SetDictionary(const wxMemoryBuffer &buf);
  91     //@}
  92 };
  93
  94
  95
  96 /**
  97     @class wxZlibInputStream
  98
  99     This filter stream decompresses a stream that is in zlib or gzip format.
 100     Note that reading the gzip format requires zlib version 1.2.1 or greater,
 101     (the builtin version does support gzip format).
 102
 103     The stream is not seekable, wxInputStream::SeekI returns ::wxInvalidOffset.
 104     Also wxStreamBase::GetSize() is not supported, it always returns 0.
 105
 106     @library{wxbase}
 107     @category{archive,streams}
 108
 109     @see wxInputStream, wxZlibOutputStream.
 110 */
 111 class wxZlibInputStream : public wxFilterInputStream
 112 {
 113 public:
 114     //@{
 115     /**
 116         If the parent stream is passed as a pointer then the new filter stream
 117         takes ownership of it. If it is passed by reference then it does not.
 118
 119         The @a flags wxZLIB_ZLIB and wxZLIB_GZIP specify whether the input data
 120         is in zlib or gzip format. If wxZLIB_AUTO is used, then zlib will
 121         autodetect the stream type, this is the default.
 122
 123         If @a flags is wxZLIB_NO_HEADER, then the data is assumed to be a raw
 124         deflate stream without either zlib or gzip headers. This is a lower level
 125         mode, which is not usually used directly. It can be used to read a raw
 126         deflate stream embedded in a higher level protocol.
 127
 128         The values of the ::wxZLibFlags enumeration can be used.
 129     */
 130     wxZlibInputStream(wxInputStream& stream, int flags = wxZLIB_AUTO);
 131     wxZlibInputStream(wxInputStream* stream, int flags = wxZLIB_AUTO);
 132     //@}
 133
 134     /**
 135         Returns @true if zlib library in use can handle gzip compressed data.
 136     */
 137     static bool CanHandleGZip();
 138
 139     //@{
 140     /**
 141         Sets the dictionary to the specified chunk of data. This can improve
 142         compression rate but note that the dictionary has to be the same when
 143         you deflate the data as when you inflate the data, otherwise you
 144         will inflate corrupted data.
 145
 146         Returns @true if the dictionary was successfully set.
 147     */
 148     bool SetDictionary(const char *data, const size_t datalen);
 149     bool SetDictionary(const wxMemoryBuffer &buf);
 150     //@}
 151 };
 152