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}\label{wxinputstreamctor}
  22
  23 \func{}{wxInputStream}{\void}
  24
  25 Creates a dummy input stream.
  26
  27 \membersection{wxInputStream::\destruct{wxInputStream}}\label{wxinputstreamdtor}
  28
  29 \func{}{\destruct{wxInputStream}}{\void}
  30
  31 Destructor.
  32
  33 \membersection{wxInputStream::CanRead}\label{wxinputstreamcanread}
  34
  35 \constfunc{bool}{CanRead}{\void}
  36
  37 Returns true if some data is available in the stream right now, so that
  38 calling \helpref{Read()}{wxinputstreamread} wouldn't block.
  39
  40 \membersection{wxInputStream::GetC}\label{wxinputstreamgetc}
  41
  42 \func{char}{GetC}{\void}
  43
  44 Returns the first character in the input queue and removes it,
  45 blocking until it appears if necessary.
  46
  47 \wxheading{Note}
  48
  49 If EOF, return value is undefined and LastRead() will return 0 and not 1.
  50
  51 \membersection{wxInputStream::Eof}\label{wxinputstreameof}
  52
  53 \constfunc{bool}{Eof}{\void}
  54
  55 Returns true after an attempt has been made to read past the end of the
  56 stream.
  57
  58 \wxheading{Note}
  59
  60 In wxWidgets 2.6.x and below some streams returned Eof() when the last
  61 byte had been read rather than when an attempt had been made to read
  62 past the last byte. If you want to avoid depending on one behaviour or
  63 the other then call \helpref{LastRead()}{wxinputstreamlastread} to
  64 check the number of bytes actually read.
  65
  66 \membersection{wxInputStream::LastRead}\label{wxinputstreamlastread}
  67
  68 \constfunc{size\_t}{LastRead}{\void}
  69
  70 Returns the last number of bytes read.
  71
  72 \membersection{wxInputStream::Peek}\label{wxinputstreampeek}
  73
  74 \func{char}{Peek}{\void}
  75
  76 Returns the first character in the input queue without removing it.
  77
  78 \wxheading{Note}
  79
  80 Blocks until something appears in the stream if necessary, if nothing
  81 ever does (i.e. EOF) LastRead() will return 0 (and the return value is
  82 undefined), otherwise LastRead() returns 1.
  83
  84 \membersection{wxInputStream::Read}\label{wxinputstreamread}
  85
  86 \func{wxInputStream\&}{Read}{\param{void *}{buffer}, \param{size\_t}{ size}}
  87
  88 Reads the specified amount of bytes and stores the data in {\it buffer}.
  89
  90 \wxheading{Warning}
  91
  92 The buffer absolutely needs to have at least the specified size.
  93
  94 \wxheading{Return value}
  95
  96 This function returns a reference on the current object, so the user can test
  97 any states of the stream right away.
  98
  99 \func{wxInputStream\&}{Read}{\param{wxOutputStream\&}{ stream\_out}}
 100
 101 Reads data from the input queue and stores it in the specified output stream.
 102 The data is read until an error is raised by one of the two streams.
 103
 104 \wxheading{Return value}
 105
 106 This function returns a reference on the current object, so the user can test
 107 any states of the stream right away.
 108
 109 \membersection{wxInputStream::SeekI}\label{wxinputstreamseeki}
 110
 111 \func{off\_t}{SeekI}{\param{off\_t}{ pos}, \param{wxSeekMode}{ mode = wxFromStart}}
 112
 113 Changes the stream current position.
 114
 115 \wxheading{Parameters}
 116
 117 \docparam{pos}{Offset to seek to.}
 118
 119 \docparam{mode}{One of {\bf wxFromStart}, {\bf wxFromEnd}, {\bf wxFromCurrent}.}
 120
 121 \wxheading{Return value}
 122
 123 The new stream position or wxInvalidOffset on error.
 124
 125 \membersection{wxInputStream::TellI}\label{wxinputstreamtelli}
 126
 127 \constfunc{off\_t}{TellI}{\void}
 128
 129 Returns the current stream position.
 130
 131 \membersection{wxInputStream::Ungetch}\label{wxinputstreamungetch}
 132
 133 \func{size\_t}{Ungetch}{\param{const char*}{ buffer}, \param{size\_t}{ size}}
 134
 135 This function is only useful in {\it read} mode. It is the manager of the "Write-Back"
 136 buffer. This buffer acts like a temporary buffer where data which has to be
 137 read during the next read IO call are put. This is useful when you get a big
 138 block of data which you didn't want to read: you can replace them at the top
 139 of the input queue by this way.
 140
 141 Be very careful about this call in connection with calling SeekI() on the same
 142 stream. Any call to SeekI() will invalidate any previous call to this method
 143 (otherwise you could SeekI() to one position, "unread" a few bytes there, SeekI()
 144 to another position and data would be either lost or corrupted).
 145
 146 \wxheading{Return value}
 147
 148 Returns the amount of bytes saved in the Write-Back buffer.
 149
 150 \func{bool}{Ungetch}{\param{char }{c}}
 151
 152 This function acts like the previous one except that it takes only one
 153 character: it is sometimes shorter to use than the generic function.
 154