docs/latex/wx/inputstr.tex

   1 % -----------------------------------------------------------------------------
   2 % wxInputStream
   3 % -----------------------------------------------------------------------------
   4 \section{\class{wxInputStream}}\label{wxinputstream}
   5
   6 wxInputStream is an abstract base class which may not be used directly.
   7
   8 \wxheading{Derived from}
   9
  10 \helpref{wxStreamBase}{wxstreambase}
  11
  12 \wxheading{Include files}
  13
  14 <wx/stream.h>
  15
  16 \latexignore{\rtfignore{\wxheading{Members}}}
  17
  18 % -----------
  19 % ctor & dtor
  20 % -----------
  21 \membersection{wxInputStream::wxInputStream}
  22
  23 \func{}{wxInputStream}{\void}
  24
  25 Creates a dummy input stream.
  26
  27 \membersection{wxInputStream::\destruct{wxInputStream}}
  28
  29 \func{}{\destruct{wxInputStream}}{\void}
  30
  31 Destructor.
  32
  33 \membersection{wxInputStream::GetC}
  34
  35 \func{char}{GetC}{\void}
  36
  37 Returns the first character in the input queue and removes it,
  38 blocking until it appears if necessary.
  39
  40 \wxheading{Note}
  41
  42 If EOF, return value is undefined and LastRead() will return 0 and not 1.
  43
  44 \membersection{wxInputStream::Eof}\label{wxinputstreameof}
  45
  46 \constfunc{wxInputStream}{Eof}{\void}
  47
  48 Returns true if the end of stream has been reached.
  49
  50 \wxheading{Note}
  51
  52 For some streams Eof() will not return true until an
  53 attempt has been made to read past the end of the stream.
  54 \helpref{LastRead()}{wxinputstreamlastread}
  55 should be called after each read to check that
  56 a non-zero number of bytes have been read.
  57
  58 \membersection{wxInputStream::LastRead}\label{wxinputstreamlastread}
  59
  60 \constfunc{size\_t}{LastRead}{\void}
  61
  62 Returns the last number of bytes read.
  63
  64 \membersection{wxInputStream::Peek}
  65
  66 \func{char}{Peek}{\void}
  67
  68 Returns the first character in the input queue without removing it.
  69
  70 \wxheading{Note}
  71
  72 Blocks until something appears in the stream if necessary, if nothing
  73 ever does (i.e. EOF) LastRead() will return 0 (and the return value is
  74 undefined), otherwise LastRead() returns 1.
  75
  76 \membersection{wxInputStream::Read}
  77
  78 \func{wxInputStream\&}{Read}{\param{void *}{buffer}, \param{size\_t}{ size}}
  79
  80 Reads the specified amount of bytes and stores the data in {\it buffer}.
  81
  82 \wxheading{Warning}
  83
  84 The buffer absolutely needs to have at least the specified size.
  85
  86 \wxheading{Return value}
  87
  88 This function returns a reference on the current object, so the user can test
  89 any states of the stream right away.
  90
  91 \func{wxInputStream\&}{Read}{\param{wxOutputStream\&}{ stream\_out}}
  92
  93 Reads data from the input queue and stores it in the specified output stream.
  94 The data is read until an error is raised by one of the two streams.
  95
  96 \wxheading{Return value}
  97
  98 This function returns a reference on the current object, so the user can test
  99 any states of the stream right away.
 100
 101 \membersection{wxInputStream::SeekI}\label{wxinputstreamseeki}
 102
 103 \func{off\_t}{SeekI}{\param{off\_t}{ pos}, \param{wxSeekMode}{ mode = wxFromStart}}
 104
 105 Changes the stream current position.
 106
 107 \wxheading{Parameters}
 108
 109 \docparam{pos}{Offset to seek to.}
 110
 111 \docparam{mode}{One of {\bf wxFromStart}, {\bf wxFromEnd}, {\bf wxFromCurrent}.}
 112
 113 \wxheading{Return value}
 114
 115 The new stream position or wxInvalidOffset on error.
 116
 117 \membersection{wxInputStream::TellI}
 118
 119 \constfunc{off\_t}{TellI}{\void}
 120
 121 Returns the current stream position.
 122
 123 \membersection{wxInputStream::Ungetch}\label{wxinputstreamungetch}
 124
 125 \func{size\_t}{Ungetch}{\param{const char*}{ buffer}, \param{size\_t}{ size}}
 126
 127 This function is only useful in {\it read} mode. It is the manager of the "Write-Back"
 128 buffer. This buffer acts like a temporary buffer where data which has to be
 129 read during the next read IO call are put. This is useful when you get a big
 130 block of data which you didn't want to read: you can replace them at the top
 131 of the input queue by this way.
 132
 133 Be very careful about this call in connection with calling SeekI() on the same
 134 stream. Any call to SeekI() will invalidate any previous call to this method
 135 (otherwise you could SeekI() to one position, "unread" a few bytes there, SeekI()
 136 to another position and data would be either lost or corrupted).
 137
 138 \wxheading{Return value}
 139
 140 Returns the amount of bytes saved in the Write-Back buffer.
 141
 142 \func{bool}{Ungetch}{\param{char }{c}}
 143
 144 This function acts like the previous one except that it takes only one
 145 character: it is sometimes shorter to use than the generic function.
 146