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 \wxheading{Library}
  17
  18 \helpref{wxBase}{librarieslist}
  19
  20 \latexignore{\rtfignore{\wxheading{Members}}}
  21
  22 % -----------
  23 % ctor & dtor
  24 % -----------
  25 \membersection{wxInputStream::wxInputStream}\label{wxinputstreamctor}
  26
  27 \func{}{wxInputStream}{\void}
  28
  29 Creates a dummy input stream.
  30
  31 \membersection{wxInputStream::\destruct{wxInputStream}}\label{wxinputstreamdtor}
  32
  33 \func{}{\destruct{wxInputStream}}{\void}
  34
  35 Destructor.
  36
  37 \membersection{wxInputStream::CanRead}\label{wxinputstreamcanread}
  38
  39 \constfunc{bool}{CanRead}{\void}
  40
  41 Returns true if some data is available in the stream right now, so that
  42 calling \helpref{Read()}{wxinputstreamread} wouldn't block.
  43
  44 \membersection{wxInputStream::GetC}\label{wxinputstreamgetc}
  45
  46 \func{char}{GetC}{\void}
  47
  48 Returns the first character in the input queue and removes it,
  49 blocking until it appears if necessary.
  50
  51 \wxheading{Note}
  52
  53 If EOF, return value is undefined and LastRead() will return 0 and not 1.
  54
  55 \membersection{wxInputStream::Eof}\label{wxinputstreameof}
  56
  57 \constfunc{bool}{Eof}{\void}
  58
  59 Returns true after an attempt has been made to read past the end of the
  60 stream.
  61
  62 \wxheading{Note}
  63
  64 In wxWidgets 2.6.x and below some streams returned Eof() when the last
  65 byte had been read rather than when an attempt had been made to read
  66 past the last byte. If you want to avoid depending on one behaviour or
  67 the other then call \helpref{LastRead()}{wxinputstreamlastread} to
  68 check the number of bytes actually read.
  69
  70 \membersection{wxInputStream::LastRead}\label{wxinputstreamlastread}
  71
  72 \constfunc{size\_t}{LastRead}{\void}
  73
  74 Returns the last number of bytes read.
  75
  76 \membersection{wxInputStream::Peek}\label{wxinputstreampeek}
  77
  78 \func{char}{Peek}{\void}
  79
  80 Returns the first character in the input queue without removing it.
  81
  82 \wxheading{Note}
  83
  84 Blocks until something appears in the stream if necessary, if nothing
  85 ever does (i.e. EOF) LastRead() will return 0 (and the return value is
  86 undefined), otherwise LastRead() returns 1.
  87
  88 \membersection{wxInputStream::Read}\label{wxinputstreamread}
  89
  90 \func{wxInputStream\&}{Read}{\param{void *}{buffer}, \param{size\_t}{ size}}
  91
  92 Reads the specified amount of bytes and stores the data in {\it buffer}.
  93
  94 \wxheading{Warning}
  95
  96 The buffer absolutely needs to have at least the specified size.
  97
  98 \wxheading{Return value}
  99
 100 This function returns a reference on the current object, so the user can test
 101 any states of the stream right away.
 102
 103 \func{wxInputStream\&}{Read}{\param{wxOutputStream\&}{ stream\_out}}
 104
 105 Reads data from the input queue and stores it in the specified output stream.
 106 The data is read until an error is raised by one of the two streams.
 107
 108 \wxheading{Return value}
 109
 110 This function returns a reference on the current object, so the user can test
 111 any states of the stream right away.
 112
 113 \membersection{wxInputStream::SeekI}\label{wxinputstreamseeki}
 114
 115 \func{off\_t}{SeekI}{\param{off\_t}{ pos}, \param{wxSeekMode}{ mode = wxFromStart}}
 116
 117 Changes the stream current position.
 118
 119 \wxheading{Parameters}
 120
 121 \docparam{pos}{Offset to seek to.}
 122
 123 \docparam{mode}{One of {\bf wxFromStart}, {\bf wxFromEnd}, {\bf wxFromCurrent}.}
 124
 125 \wxheading{Return value}
 126
 127 The new stream position or wxInvalidOffset on error.
 128
 129 \membersection{wxInputStream::TellI}\label{wxinputstreamtelli}
 130
 131 \constfunc{off\_t}{TellI}{\void}
 132
 133 Returns the current stream position.
 134
 135 \membersection{wxInputStream::Ungetch}\label{wxinputstreamungetch}
 136
 137 \func{size\_t}{Ungetch}{\param{const char*}{ buffer}, \param{size\_t}{ size}}
 138
 139 This function is only useful in {\it read} mode. It is the manager of the "Write-Back"
 140 buffer. This buffer acts like a temporary buffer where data which has to be
 141 read during the next read IO call are put. This is useful when you get a big
 142 block of data which you didn't want to read: you can replace them at the top
 143 of the input queue by this way.
 144
 145 Be very careful about this call in connection with calling SeekI() on the same
 146 stream. Any call to SeekI() will invalidate any previous call to this method
 147 (otherwise you could SeekI() to one position, "unread" a few bytes there, SeekI()
 148 to another position and data would be either lost or corrupted).
 149
 150 \wxheading{Return value}
 151
 152 Returns the amount of bytes saved in the Write-Back buffer.
 153
 154 \func{bool}{Ungetch}{\param{char }{c}}
 155
 156 This function acts like the previous one except that it takes only one
 157 character: it is sometimes shorter to use than the generic function.
 158