docs/latex/wx/datistrm.tex

   1 \section{\class{wxDataInputStream}}\label{wxdatainputstream}
   2
   3 This class provides functions that read binary data types in a
   4 portable way. Data can be read in either big-endian or little-endian
   5 format, little-endian being the default on all architectures.
   6
   7 If you want to read data from text files (or streams) use
   8 \helpref{wxTextInputStream}{wxtextinputstream} instead.
   9
  10 The >> operator is overloaded and you can use this class like a standard C++ iostream.
  11 Note, however, that the arguments are the fixed size types wxUint32, wxInt32 etc
  12 and on a typical 32-bit computer, none of these match to the "long" type (wxInt32
  13 is defined as signed int on 32-bit architectures) so that you cannot use long. To avoid
  14 problems (here and elsewhere), make use of the wxInt32, wxUint32, etc types.
  15
  16 For example:
  17
  18 \begin{verbatim}
  19   wxFileInputStream input( "mytext.dat" );
  20   wxDataInputStream store( input );
  21   wxUint8 i1;
  22   float f2;
  23   wxString line;
  24
  25   store >> i1;       // read a 8 bit integer.
  26   store >> i1 >> f2; // read a 8 bit integer followed by float.
  27   store >> line;     // read a text line
  28 \end{verbatim}
  29
  30 See also \helpref{wxDataOutputStream}{wxdataoutputstream}.
  31
  32 \wxheading{Derived from}
  33
  34 None
  35
  36 \wxheading{Include files}
  37
  38 <wx/datstrm.h>
  39
  40 \wxheading{Library}
  41
  42 \helpref{wxBase}{librarieslist}
  43
  44 \latexignore{\rtfignore{\wxheading{Members}}}
  45
  46 \membersection{wxDataInputStream::wxDataInputStream}\label{wxdatainputstreamctor}
  47
  48 \func{}{wxDataInputStream}{\param{wxInputStream\&}{ stream}}
  49
  50 \func{}{wxDataInputStream}{\param{wxInputStream\&}{ stream}, \param{const wxMBConv\&}{ conv = wxConvAuto()}}
  51
  52 Constructs a datastream object from an input stream. Only read methods will
  53 be available. The second form is only available in Unicode build of wxWidgets.
  54
  55 \wxheading{Parameters}
  56
  57 \docparam{stream}{The input stream.}
  58
  59 \docparam{conv}{Charset conversion object object used to decode strings in Unicode
  60 mode (see \helpref{wxDataInputStream::ReadString}{wxdatainputstreamreadstring}
  61 documentation for detailed description). Note that you must not destroy
  62 {\it conv} before you destroy this wxDataInputStream instance!}
  63
  64 \membersection{wxDataInputStream::\destruct{wxDataInputStream}}\label{wxdatainputstreamdtor}
  65
  66 \func{}{\destruct{wxDataInputStream}}{\void}
  67
  68 Destroys the wxDataInputStream object.
  69
  70 \membersection{wxDataInputStream::BigEndianOrdered}\label{wxdatainputstreambigendianordered}
  71
  72 \func{void}{BigEndianOrdered}{\param{bool}{ be\_order}}
  73
  74 If {\it be\_order} is true, all data will be read in big-endian
  75 order, such as written by programs on a big endian architecture
  76 (e.g. Sparc) or written by Java-Streams (which always use
  77 big-endian order).
  78
  79 \membersection{wxDataInputStream::Read8}\label{wxdatainputstreamread8}
  80
  81 \func{wxUint8}{Read8}{\void}
  82
  83 Reads a single byte from the stream.
  84
  85 \func{void}{Read8}{\param{wxUint8 *}{buffer}, \param{size\_t }{size}}
  86
  87 Reads bytes from the stream in a specified buffer. The amount of
  88 bytes to read is specified by the {\it size} variable.
  89
  90 \membersection{wxDataInputStream::Read16}\label{wxdatainputstreamread16}
  91
  92 \func{wxUint16}{Read16}{\void}
  93
  94 Reads a 16 bit unsigned integer from the stream.
  95
  96 \func{void}{Read16}{\param{wxUint16 *}{buffer}, \param{size\_t }{size}}
  97
  98 Reads 16 bit unsigned integers from the stream in a specified buffer. the
  99 amount of 16 bit unsigned integer to read is specified by the {\it size} variable.
 100
 101 \membersection{wxDataInputStream::Read32}\label{wxdatainputstreamread32}
 102
 103 \func{wxUint32}{Read32}{\void}
 104
 105 Reads a 32 bit unsigned integer from the stream.
 106
 107 \func{void}{Read32}{\param{wxUint32 *}{buffer}, \param{size\_t }{size}}
 108
 109 Reads 32 bit unsigned integers from the stream in a specified buffer. the amount of
 110 32 bit unsigned integer to read is specified by the {\it size} variable.
 111
 112 \membersection{wxDataInputStream::Read64}\label{wxdatainputstreamread64}
 113
 114 \func{wxUint64}{Read64}{\void}
 115
 116 Reads a 64 bit unsigned integer from the stream.
 117
 118 \func{void}{Read64}{\param{wxUint64 *}{buffer}, \param{size\_t }{size}}
 119
 120 Reads 64 bit unsigned integers from the stream in a specified buffer. the amount of
 121 64 bit unsigned integer to read is specified by the {\it size} variable.
 122
 123 \membersection{wxDataInputStream::ReadDouble}\label{wxdatainputstreamreaddouble}
 124
 125 \func{double}{ReadDouble}{\void}
 126
 127 Reads a double (IEEE encoded) from the stream.
 128
 129 \func{void}{ReadDouble}{\param{double *}{buffer}, \param{size\_t }{size}}
 130
 131 Reads double data (IEEE encoded) from the stream in a specified buffer. the amount of
 132 double to read is specified by the {\it size} variable.
 133
 134 \membersection{wxDataInputStream::ReadString}\label{wxdatainputstreamreadstring}
 135
 136 \func{wxString}{ReadString}{\void}
 137
 138 Reads a string from a stream. Actually, this function first reads a long
 139 integer specifying the length of the string (without the last null character)
 140 and then reads the string.
 141
 142 In Unicode build of wxWidgets, the fuction first reads multibyte (char*)
 143 string from the stream and then converts it to Unicode using the {\it conv}
 144 object passed to constructor and returns the result as wxString. You are
 145 responsible for using the same convertor as when writing the stream.
 146
 147 See also \helpref{wxDataOutputStream::WriteString}{wxdataoutputstreamwritestring}.
 148