wxWidgets/docs/latex/wx/datistrm.tex

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\section{\class{wxDataInputStream}}\label{wxdatainputstream}
This class provides functions that read binary data types in a
portable way. Data can be read in either big-endian or little-endian
format, little-endian being the default on all architectures.
If you want to read data from text files (or streams) use
\helpref{wxTextInputStream}{wxtextinputstream} instead.
The >> operator is overloaded and you can use this class like a standard C++ iostream.
Note, however, that the arguments are the fixed size types wxUint32, wxInt32 etc
and on a typical 32-bit computer, none of these match to the "long" type (wxInt32
is defined as signed int on 32-bit architectures) so that you cannot use long. To avoid
problems (here and elsewhere), make use of the wxInt32, wxUint32, etc types.
For example:
\begin{verbatim}
wxFileInputStream input( "mytext.dat" );
wxDataInputStream store( input );
wxUint8 i1;
float f2;
wxString line;
store >> i1; // read a 8 bit integer.
store >> i1 >> f2; // read a 8 bit integer followed by float.
store >> line; // read a text line
\end{verbatim}
See also \helpref{wxDataOutputStream}{wxdataoutputstream}.
\wxheading{Derived from}
None
\wxheading{Include files}
<wx/datstrm.h>
\latexignore{\rtfignore{\wxheading{Members}}}
\membersection{wxDataInputStream::wxDataInputStream}\label{wxdatainputstreamconstr}
\func{}{wxDataInputStream}{\param{wxInputStream\&}{ stream}}
\func{}{wxDataInputStream}{\param{wxInputStream\&}{ stream}, \param{wxMBConv\&}{ conv = wxMBConvUTF8}}
Constructs a datastream object from an input stream. Only read methods will
be available. The second form is only available in Unicode build of wxWindows.
\wxheading{Parameters}
\docparam{stream}{The input stream.}
\docparam{conv}{Charset conversion object object used to decode strings in Unicode
mode (see \helpref{wxDataInputStream::ReadString}{wxdatainputstreamreadstring}
documentation for detailed description). Note that you must not destroy
{\it conv} before you destroy this wxDataInputStream instance!}
\membersection{wxDataInputStream::\destruct{wxDataInputStream}}
\func{}{\destruct{wxDataInputStream}}{\void}
Destroys the wxDataInputStream object.
\membersection{wxDataInputStream::BigEndianOrdered}
\func{void}{BigEndianOrdered}{\param{bool}{ be\_order}}
If {\it be\_order} is true, all data will be read in big-endian
order, such as written by programs on a big endian architecture
(e.g. Sparc) or written by Java-Streams (which always use
big-endian order).
\membersection{wxDataInputStream::Read8}
\func{wxUint8}{Read8}{\void}
Reads a single byte from the stream.
\func{void}{Read8}{\param{wxUint8 *}{buffer}, \param{size\_t }{size}}
Reads bytes from the stream in a specified buffer. The amount of
bytes to read is specified by the {\it size} variable.
\membersection{wxDataInputStream::Read16}
\func{wxUint16}{Read16}{\void}
Reads a 16 bit unsigned integer from the stream.
\func{void}{Read16}{\param{wxUint16 *}{buffer}, \param{size\_t }{size}}
Reads 16 bit unsigned integers from the stream in a specified buffer. the
amount of 16 bit unsigned integer to read is specified by the {\it size} variable.
\membersection{wxDataInputStream::Read32}
\func{wxUint32}{Read32}{\void}
Reads a 32 bit unsigned integer from the stream.
\func{void}{Read32}{\param{wxUint32 *}{buffer}, \param{size\_t }{size}}
Reads 32 bit unsigned integers from the stream in a specified buffer. the amount of
32 bit unsigned integer to read is specified by the {\it size} variable.
\membersection{wxDataInputStream::Read64}
\func{wxUint64}{Read64}{\void}
Reads a 64 bit unsigned integer from the stream.
\func{void}{Read64}{\param{wxUint64 *}{buffer}, \param{size\_t }{size}}
Reads 64 bit unsigned integers from the stream in a specified buffer. the amount of
64 bit unsigned integer to read is specified by the {\it size} variable.
\membersection{wxDataInputStream::ReadDouble}
\func{double}{ReadDouble}{\void}
Reads a double (IEEE encoded) from the stream.
\func{void}{ReadDouble}{\param{double *}{buffer}, \param{size\_t }{size}}
Reads double data (IEEE encoded) from the stream in a specified buffer. the amount of
double to read is specified by the {\it size} variable.
\membersection{wxDataInputStream::ReadString}\label{wxdatainputstreamreadstring}
\func{wxString}{ReadString}{\void}
Reads a string from a stream. Actually, this function first reads a long
integer specifying the length of the string (without the last null character)
and then reads the string.
In Unicode build of wxWindows, the fuction first reads multibyte (char*)
string from the stream and then converts it to Unicode using the {\it conv}
object passed to constructor and returns the result as wxString. You are
responsible for using the same convertor as when writing the stream.
See also \helpref{wxDataOutputStream::WriteString}{wxdataoutputstreamwritestring}.