a99acbb00a
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@16246 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
113 lines
3.6 KiB
TeX
113 lines
3.6 KiB
TeX
\section{\class{wxDataInputStream}}\label{wxdatainputstream}
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This class provides functions that read binary data types in a
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portable way. Data can be read in either big-endian or little-endian
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format, little-endian being the default on all architectures.
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If you want to read data from text files (or streams) use
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\helpref{wxTextInputStream}{wxtextinputstream} instead.
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The >> operator is overloaded and you can use this class like a standard C++ iostream.
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Note, however, that the arguments are the fixed size types wxUint32, wxInt32 etc
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and on a typical 32-bit computer, none of these match to the "long" type (wxInt32
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is defined as signed int on 32-bit architectures) so that you cannot use long. To avoid
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problems (here and elsewhere), make use of the wxInt32, wxUint32, etc types.
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For example:
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\begin{verbatim}
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wxFileInputStream input( "mytext.dat" );
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wxDataInputStream store( input );
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wxUint8 i1;
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float f2;
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wxString line;
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store >> i1; // read a 8 bit integer.
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store >> i1 >> f2; // read a 8 bit integer followed by float.
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store >> line; // read a text line
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\end{verbatim}
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See also \helpref{wxDataOutputStream}{wxdataoutputstream}.
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\wxheading{Derived from}
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None
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\wxheading{Include files}
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<wx/datstrm.h>
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\latexignore{\rtfignore{\wxheading{Members}}}
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\membersection{wxDataInputStream::wxDataInputStream}\label{wxdatainputstreamconstr}
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\func{}{wxDataInputStream}{\param{wxInputStream\&}{ stream}}
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\func{}{wxDataInputStream}{\param{wxInputStream\&}{ stream}, \param{wxMBConv\&}{ conv = wxMBConvUTF8}}
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Constructs a datastream object from an input stream. Only read methods will
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be available. The second form is only available in Unicode build of wxWindows.
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\wxheading{Parameters}
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\docparam{stream}{The input stream.}
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\docparam{conv}{Charset conversion object object used to decode strings in Unicode
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mode (see \helpref{wxDataInputStream::ReadString}{wxdatainputstreamreadstring}
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documentation for detailed description). Note that you must not destroy
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{\it conv} before you destroy this wxDataInputStream instance!}
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\membersection{wxDataInputStream::\destruct{wxDataInputStream}}
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\func{}{\destruct{wxDataInputStream}}{\void}
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Destroys the wxDataInputStream object.
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\membersection{wxDataInputStream::BigEndianOrdered}
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\func{void}{BigEndianOrdered}{\param{bool}{ be\_order}}
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If {\it be\_order} is TRUE, all data will be read in big-endian
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order, such as written by programs on a big endian architecture
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(e.g. Sparc) or written by Java-Streams (which always use
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big-endian order).
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\membersection{wxDataInputStream::Read8}
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\func{wxUint8}{Read8}{\void}
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Reads a single byte from the stream.
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\membersection{wxDataInputStream::Read16}
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\func{wxUint16}{Read16}{\void}
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Reads a 16 bit integer from the stream.
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\membersection{wxDataInputStream::Read32}
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\func{wxUint32}{Read32}{\void}
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Reads a 32 bit integer from the stream.
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\membersection{wxDataInputStream::ReadDouble}
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\func{double}{ReadDouble}{\void}
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Reads a double (IEEE encoded) from the stream.
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\membersection{wxDataInputStream::ReadString}\label{wxdatainputstreamreadstring}
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\func{wxString}{ReadString}{\void}
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Reads a string from a stream. Actually, this function first reads a long
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integer specifying the length of the string (without the last null character)
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and then reads the string.
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In Unicode build of wxWindows, the fuction first reads multibyte (char*)
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string from the stream and then converts it to Unicode using the {\it conv}
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object passed to constructor and returns the result as wxString. You are
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responsible for using the same convertor as when writing the stream.
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See also \helpref{wxDataOutputStream::WriteString}{wxdataoutputstreamwritestring}.
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