interface/wx/zstream.h

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