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 \latexignore{\rtfignore{\wxheading{Members}}}
  41
  42 \membersection{wxDataInputStream::wxDataInputStream}\label{wxdatainputstreamctor}
  43
  44 \func{}{wxDataInputStream}{\param{wxInputStream\&}{ stream}}
  45
  46 \func{}{wxDataInputStream}{\param{wxInputStream\&}{ stream}, \param{wxMBConv\&}{ conv = wxMBConvUTF8}}
  47
  48 Constructs a datastream object from an input stream. Only read methods will
  49 be available. The second form is only available in Unicode build of wxWidgets.
  50
  51 \wxheading{Parameters}
  52
  53 \docparam{stream}{The input stream.}
  54
  55 \docparam{conv}{Charset conversion object object used to decode strings in Unicode
  56 mode (see \helpref{wxDataInputStream::ReadString}{wxdatainputstreamreadstring}
  57 documentation for detailed description). Note that you must not destroy
  58 {\it conv} before you destroy this wxDataInputStream instance!}
  59
  60 \membersection{wxDataInputStream::\destruct{wxDataInputStream}}\label{wxdatainputstreamdtor}
  61
  62 \func{}{\destruct{wxDataInputStream}}{\void}
  63
  64 Destroys the wxDataInputStream object.
  65
  66 \membersection{wxDataInputStream::BigEndianOrdered}\label{wxdatainputstreambigendianordered}
  67
  68 \func{void}{BigEndianOrdered}{\param{bool}{ be\_order}}
  69
  70 If {\it be\_order} is true, all data will be read in big-endian
  71 order, such as written by programs on a big endian architecture
  72 (e.g. Sparc) or written by Java-Streams (which always use
  73 big-endian order).
  74
  75 \membersection{wxDataInputStream::Read8}\label{wxdatainputstreamread8}
  76
  77 \func{wxUint8}{Read8}{\void}
  78
  79 Reads a single byte from the stream.
  80
  81 \func{void}{Read8}{\param{wxUint8 *}{buffer}, \param{size\_t }{size}}
  82
  83 Reads bytes from the stream in a specified buffer. The amount of
  84 bytes to read is specified by the {\it size} variable.
  85
  86 \membersection{wxDataInputStream::Read16}\label{wxdatainputstreamread16}
  87
  88 \func{wxUint16}{Read16}{\void}
  89
  90 Reads a 16 bit unsigned integer from the stream.
  91
  92 \func{void}{Read16}{\param{wxUint16 *}{buffer}, \param{size\_t }{size}}
  93
  94 Reads 16 bit unsigned integers from the stream in a specified buffer. the
  95 amount of 16 bit unsigned integer to read is specified by the {\it size} variable.
  96
  97 \membersection{wxDataInputStream::Read32}\label{wxdatainputstreamread32}
  98
  99 \func{wxUint32}{Read32}{\void}
 100
 101 Reads a 32 bit unsigned integer from the stream.
 102
 103 \func{void}{Read32}{\param{wxUint32 *}{buffer}, \param{size\_t }{size}}
 104
 105 Reads 32 bit unsigned integers from the stream in a specified buffer. the amount of
 106 32 bit unsigned integer to read is specified by the {\it size} variable.
 107
 108 \membersection{wxDataInputStream::Read64}\label{wxdatainputstreamread64}
 109
 110 \func{wxUint64}{Read64}{\void}
 111
 112 Reads a 64 bit unsigned integer from the stream.
 113
 114 \func{void}{Read64}{\param{wxUint64 *}{buffer}, \param{size\_t }{size}}
 115
 116 Reads 64 bit unsigned integers from the stream in a specified buffer. the amount of
 117 64 bit unsigned integer to read is specified by the {\it size} variable.
 118
 119 \membersection{wxDataInputStream::ReadDouble}\label{wxdatainputstreamreaddouble}
 120
 121 \func{double}{ReadDouble}{\void}
 122
 123 Reads a double (IEEE encoded) from the stream.
 124
 125 \func{void}{ReadDouble}{\param{double *}{buffer}, \param{size\_t }{size}}
 126
 127 Reads double data (IEEE encoded) from the stream in a specified buffer. the amount of
 128 double to read is specified by the {\it size} variable.
 129
 130 \membersection{wxDataInputStream::ReadString}\label{wxdatainputstreamreadstring}
 131
 132 \func{wxString}{ReadString}{\void}
 133
 134 Reads a string from a stream. Actually, this function first reads a long
 135 integer specifying the length of the string (without the last null character)
 136 and then reads the string.
 137
 138 In Unicode build of wxWidgets, the fuction first reads multibyte (char*)
 139 string from the stream and then converts it to Unicode using the {\it conv}
 140 object passed to constructor and returns the result as wxString. You are
 141 responsible for using the same convertor as when writing the stream.
 142
 143 See also \helpref{wxDataOutputStream::WriteString}{wxdataoutputstreamwritestring}.
 144