fc1f28995d
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@30148 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
154 lines
4.5 KiB
TeX
154 lines
4.5 KiB
TeX
% -----------------------------------------------------------------------------
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% wxInputStream
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% -----------------------------------------------------------------------------
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\section{\class{wxInputStream}}\label{wxinputstream}
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wxInputStream is an abstract base class which may not be used directly.
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\wxheading{Derived from}
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\helpref{wxStreamBase}{wxstreambase}
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\wxheading{Include files}
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<wx/stream.h>
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\latexignore{\rtfignore{\wxheading{Members}}}
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% -----------
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% ctor & dtor
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% -----------
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\membersection{wxInputStream::wxInputStream}\label{wxinputstreamctor}
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\func{}{wxInputStream}{\void}
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Creates a dummy input stream.
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\membersection{wxInputStream::\destruct{wxInputStream}}\label{wxinputstreamdtor}
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\func{}{\destruct{wxInputStream}}{\void}
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Destructor.
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\membersection{wxInputStream::CanRead}\label{wxinputstreamcanread}
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\constfunc{bool}{CanRead}{\void}
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Returns true if some data is available in the stream right now, so that
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calling \helpref{Read()}{wxinputstreamread} wouldn't block.
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\membersection{wxInputStream::GetC}\label{wxinputstreamgetc}
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\func{char}{GetC}{\void}
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Returns the first character in the input queue and removes it,
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blocking until it appears if necessary.
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\wxheading{Note}
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If EOF, return value is undefined and LastRead() will return 0 and not 1.
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\membersection{wxInputStream::Eof}\label{wxinputstreameof}
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\constfunc{bool}{Eof}{\void}
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Returns true if the end of stream has been reached.
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\wxheading{Note}
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For some streams Eof() will not return true until an
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attempt has been made to read past the end of the stream.
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\helpref{LastRead()}{wxinputstreamlastread}
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should be called after each read to check that
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a non-zero number of bytes have been read.
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\membersection{wxInputStream::LastRead}\label{wxinputstreamlastread}
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\constfunc{size\_t}{LastRead}{\void}
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Returns the last number of bytes read.
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\membersection{wxInputStream::Peek}\label{wxinputstreampeek}
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\func{char}{Peek}{\void}
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Returns the first character in the input queue without removing it.
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\wxheading{Note}
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Blocks until something appears in the stream if necessary, if nothing
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ever does (i.e. EOF) LastRead() will return 0 (and the return value is
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undefined), otherwise LastRead() returns 1.
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\membersection{wxInputStream::Read}\label{wxinputstreamread}
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\func{wxInputStream\&}{Read}{\param{void *}{buffer}, \param{size\_t}{ size}}
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Reads the specified amount of bytes and stores the data in {\it buffer}.
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\wxheading{Warning}
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The buffer absolutely needs to have at least the specified size.
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\wxheading{Return value}
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This function returns a reference on the current object, so the user can test
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any states of the stream right away.
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\func{wxInputStream\&}{Read}{\param{wxOutputStream\&}{ stream\_out}}
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Reads data from the input queue and stores it in the specified output stream.
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The data is read until an error is raised by one of the two streams.
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\wxheading{Return value}
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This function returns a reference on the current object, so the user can test
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any states of the stream right away.
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\membersection{wxInputStream::SeekI}\label{wxinputstreamseeki}
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\func{off\_t}{SeekI}{\param{off\_t}{ pos}, \param{wxSeekMode}{ mode = wxFromStart}}
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Changes the stream current position.
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\wxheading{Parameters}
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\docparam{pos}{Offset to seek to.}
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\docparam{mode}{One of {\bf wxFromStart}, {\bf wxFromEnd}, {\bf wxFromCurrent}.}
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\wxheading{Return value}
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The new stream position or wxInvalidOffset on error.
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\membersection{wxInputStream::TellI}\label{wxinputstreamtelli}
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\constfunc{off\_t}{TellI}{\void}
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Returns the current stream position.
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\membersection{wxInputStream::Ungetch}\label{wxinputstreamungetch}
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\func{size\_t}{Ungetch}{\param{const char*}{ buffer}, \param{size\_t}{ size}}
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This function is only useful in {\it read} mode. It is the manager of the "Write-Back"
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buffer. This buffer acts like a temporary buffer where data which has to be
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read during the next read IO call are put. This is useful when you get a big
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block of data which you didn't want to read: you can replace them at the top
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of the input queue by this way.
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Be very careful about this call in connection with calling SeekI() on the same
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stream. Any call to SeekI() will invalidate any previous call to this method
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(otherwise you could SeekI() to one position, "unread" a few bytes there, SeekI()
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to another position and data would be either lost or corrupted).
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\wxheading{Return value}
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Returns the amount of bytes saved in the Write-Back buffer.
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\func{bool}{Ungetch}{\param{char }{c}}
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This function acts like the previous one except that it takes only one
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character: it is sometimes shorter to use than the generic function.
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