| 1 | \section{\class{wxStreamBuffer}}\label{wxstreambuffer} |
| 2 | |
| 3 | \wxheading{Derived from} |
| 4 | |
| 5 | None |
| 6 | |
| 7 | \wxheading{Include files} |
| 8 | |
| 9 | <wx/stream.h> |
| 10 | |
| 11 | \wxheading{See also} |
| 12 | |
| 13 | \helpref{wxStreamBase}{wxstreambase} |
| 14 | |
| 15 | % --------------------------------------------------------------------------- |
| 16 | % Members |
| 17 | % --------------------------------------------------------------------------- |
| 18 | \latexignore{\rtfignore{\wxheading{Members}}} |
| 19 | |
| 20 | % ----------- |
| 21 | % ctor & dtor |
| 22 | % ----------- |
| 23 | \membersection{wxStreamBuffer::wxStreamBuffer}\label{wxstreambufconst} |
| 24 | |
| 25 | \func{}{wxStreamBuffer}{\param{wxStreamBase\&}{ stream}, \param{BufMode}{ mode}} |
| 26 | |
| 27 | Constructor, creates a new stream buffer using {\it stream} as a parent stream |
| 28 | and {\it mode} as the IO mode. {\it mode} can be: wxStreamBuffer::read, |
| 29 | wxStreamBuffer::write, wxStreamBuffer::read\_write. |
| 30 | |
| 31 | One stream can have many stream buffers but only one is used internally to |
| 32 | pass IO call (e.g. wxInputStream::Read() -> wxStreamBuffer::Read()), but you |
| 33 | can call directly wxStreamBuffer::Read without any problems. Note that |
| 34 | all errors and messages linked to the stream are stored in the stream, not |
| 35 | the stream buffers: |
| 36 | |
| 37 | \begin{verbatim} |
| 38 | streambuffer.Read(...); |
| 39 | streambuffer2.Read(...); /* This call erases previous error messages set by |
| 40 | ``streambuffer'' */ |
| 41 | \end{verbatim} |
| 42 | |
| 43 | \func{}{wxStreamBuffer}{\param{BufMode}{ mode}} |
| 44 | |
| 45 | Constructor, creates a new empty stream buffer which won't flush any data |
| 46 | to a stream. {\it mode} specifies the type of the buffer (read, write, read\_write). |
| 47 | This stream buffer has the advantage to be stream independent and to |
| 48 | work only on memory buffers but it is still compatible with the rest of the |
| 49 | wxStream classes. You can write, read to this special stream and it will |
| 50 | grow (if it is allowed by the user) its internal buffer. Briefly, it has all |
| 51 | functionality of a ``normal'' stream. |
| 52 | |
| 53 | \wxheading{Warning} |
| 54 | |
| 55 | The "read\_write" mode may not work: it isn't completely finished. |
| 56 | |
| 57 | \func{}{wxStreamBuffer}{\param{const wxStreamBuffer\&}{buffer}} |
| 58 | |
| 59 | Constructor. It initializes the stream buffer with the data of the specified |
| 60 | stream buffer. The new stream buffer has the same attributes, size, position |
| 61 | and they share the same buffer. This will cause problems if the stream to |
| 62 | which the stream buffer belong is destroyed and the newly cloned stream |
| 63 | buffer continues to be used, trying to call functions in the (destroyed) |
| 64 | stream. It is advised to use this feature only in very local area of the |
| 65 | program. |
| 66 | |
| 67 | \wxheading{See also} |
| 68 | |
| 69 | \helpref{wxStreamBuffer:SetBufferIO}{wxstreambuffersetbufferio} |
| 70 | |
| 71 | \membersection{wxStreamBuffer::\destruct{wxStreamBuffer}} |
| 72 | |
| 73 | \func{}{wxStreamBuffer}{\destruct{wxStreamBuffer}} |
| 74 | |
| 75 | Destructor. It finalizes all IO calls and frees all internal buffers if |
| 76 | necessary. |
| 77 | |
| 78 | % ----------- |
| 79 | % Filtered IO |
| 80 | % ----------- |
| 81 | \membersection{wxStreamBuffer::Read}\label{wxstreambufferread} |
| 82 | |
| 83 | \func{size\_t}{Read}{\param{void *}{buffer}, \param{size\_t }{size}} |
| 84 | |
| 85 | Reads a block of the specified {\it size} and stores the data in {\it buffer}. |
| 86 | This function tries to read from the buffer first and if more data has been |
| 87 | requested, reads more data from the associated stream and updates the buffer |
| 88 | accordingly until all requested data is read. |
| 89 | |
| 90 | \wxheading{Return value} |
| 91 | |
| 92 | It returns the size of the data read. If the returned size is different of the specified |
| 93 | {\it size}, an error has occurred and should be tested using |
| 94 | \helpref{GetLastError}{wxstreambasegetlasterror}. |
| 95 | |
| 96 | \func{size\_t}{Read}{\param{wxStreamBuffer *}{buffer}} |
| 97 | |
| 98 | Reads a {\it buffer}. The function returns when {\it buffer} is full or when there isn't |
| 99 | data anymore in the current buffer. |
| 100 | |
| 101 | \wxheading{See also} |
| 102 | |
| 103 | \helpref{wxStreamBuffer::Write}{wxstreambufferwrite} |
| 104 | |
| 105 | \membersection{wxStreamBuffer::Write}\label{wxstreambufferwrite} |
| 106 | |
| 107 | \func{size\_t}{Write}{\param{const void *}{buffer}, \param{size\_t }{size}} |
| 108 | |
| 109 | Writes a block of the specified {\it size} using data of {\it buffer}. The data |
| 110 | are cached in a buffer before being sent in one block to the stream. |
| 111 | |
| 112 | \func{size\_t}{Write}{\param{wxStreamBuffer *}{buffer}} |
| 113 | |
| 114 | See \helpref{Read}{wxstreambufferread}. |
| 115 | |
| 116 | \membersection{wxStreamBuffer::GetChar} |
| 117 | |
| 118 | \func{char}{GetChar}{\void} |
| 119 | |
| 120 | Gets a single char from the stream buffer. It acts like the Read call. |
| 121 | |
| 122 | \wxheading{Problem} |
| 123 | |
| 124 | You aren't directly notified if an error occurred during the IO call. |
| 125 | |
| 126 | \wxheading{See also} |
| 127 | |
| 128 | \helpref{wxStreamBuffer::Read}{wxstreambufferread} |
| 129 | |
| 130 | \membersection{wxStreamBuffer::PutChar} |
| 131 | |
| 132 | \func{void}{PutChar}{\param{char }{c}} |
| 133 | |
| 134 | Puts a single char to the stream buffer. |
| 135 | |
| 136 | \wxheading{Problem} |
| 137 | |
| 138 | You aren't directly notified if an error occurred during the IO call. |
| 139 | |
| 140 | \wxheading{See also} |
| 141 | |
| 142 | \helpref{wxStreamBuffer::Read}{wxstreambufferwrite} |
| 143 | |
| 144 | \membersection{wxStreamBuffer::Tell} |
| 145 | |
| 146 | \constfunc{off\_t}{Tell}{\void} |
| 147 | |
| 148 | Gets the current position in the stream. This position is calculated from |
| 149 | the {\it real} position in the stream and from the internal buffer position: so |
| 150 | it gives you the position in the {\it real} stream counted from the start of |
| 151 | the stream. |
| 152 | |
| 153 | \wxheading{Return value} |
| 154 | |
| 155 | Returns the current position in the stream if possible, wxInvalidOffset in the |
| 156 | other case. |
| 157 | |
| 158 | \membersection{wxStreamBuffer::Seek}\label{wxstreambufferseek} |
| 159 | |
| 160 | \func{off\_t}{Seek}{\param{off\_t }{pos}, \param{wxSeekMode }{mode}} |
| 161 | |
| 162 | Changes the current position. |
| 163 | |
| 164 | {\it mode} may be one of the following: |
| 165 | |
| 166 | \twocolwidtha{5cm} |
| 167 | \begin{twocollist}\itemsep=0pt |
| 168 | \twocolitem{{\bf wxFromStart}}{The position is counted from the start of the stream.} |
| 169 | \twocolitem{{\bf wxFromCurrent}}{The position is counted from the current position of the stream.} |
| 170 | \twocolitem{{\bf wxFromEnd}}{The position is counted from the end of the stream.} |
| 171 | \end{twocollist} |
| 172 | |
| 173 | \wxheading{Return value} |
| 174 | |
| 175 | Upon successful completion, it returns the new offset as measured in bytes from |
| 176 | the beginning of the stream. Otherwise, it returns wxInvalidOffset. |
| 177 | |
| 178 | % -------------- |
| 179 | % Buffer control |
| 180 | % -------------- |
| 181 | \membersection{wxStreamBuffer::ResetBuffer} |
| 182 | |
| 183 | \func{void}{ResetBuffer}{\void} |
| 184 | |
| 185 | Resets to the initial state variables concerning the buffer. |
| 186 | |
| 187 | \membersection{wxStreamBuffer::SetBufferIO}\label{wxstreambuffersetbufferio} |
| 188 | |
| 189 | \func{void}{SetBufferIO}{\param{char*}{ buffer\_start}, \param{char*}{ buffer\_end}} |
| 190 | |
| 191 | Specifies which pointers to use for stream buffering. You need to pass a pointer on the |
| 192 | start of the buffer end and another on the end. The object will use this buffer |
| 193 | to cache stream data. It may be used also as a source/destination buffer when |
| 194 | you create an empty stream buffer (See \helpref{wxStreamBuffer::wxStreamBuffer}{wxstreambufconst}). |
| 195 | |
| 196 | \wxheading{Remarks} |
| 197 | |
| 198 | When you use this function, you will have to destroy the IO buffers yourself |
| 199 | after the stream buffer is destroyed or don't use it anymore. |
| 200 | In the case you use it with an empty buffer, the stream buffer will not resize |
| 201 | it when it is full. |
| 202 | |
| 203 | \wxheading{See also} |
| 204 | |
| 205 | \helpref{wxStreamBuffer constructor}{wxstreambufconst}\\ |
| 206 | \helpref{wxStreamBuffer::Fixed}{wxstreambufferfixed}\\ |
| 207 | \helpref{wxStreamBuffer::Flushable}{wxstreambufferflushable} |
| 208 | |
| 209 | \func{void}{SetBufferIO}{\param{size\_t}{ bufsize}} |
| 210 | |
| 211 | Destroys or invalidates the previous IO buffer and allocates a new one of the |
| 212 | specified size. |
| 213 | |
| 214 | \wxheading{Warning} |
| 215 | |
| 216 | All previous pointers aren't valid anymore. |
| 217 | |
| 218 | \wxheading{Remark} |
| 219 | |
| 220 | The created IO buffer is growable by the object. |
| 221 | |
| 222 | \wxheading{See also} |
| 223 | |
| 224 | \helpref{wxStreamBuffer::Fixed}{wxstreambufferfixed}\\ |
| 225 | \helpref{wxStreamBuffer::Flushable}{wxstreambufferflushable} |
| 226 | |
| 227 | \membersection{wxStreamBuffer::GetBufferStart} |
| 228 | |
| 229 | \constfunc{char *}{GetBufferStart}{\void} |
| 230 | |
| 231 | Returns a pointer on the start of the stream buffer. |
| 232 | |
| 233 | \membersection{wxStreamBuffer::GetBufferEnd} |
| 234 | |
| 235 | \constfunc{char *}{GetBufferEnd}{\void} |
| 236 | |
| 237 | Returns a pointer on the end of the stream buffer. |
| 238 | |
| 239 | \membersection{wxStreamBuffer::GetBufferPos} |
| 240 | |
| 241 | \constfunc{char *}{GetBufferPos}{\void} |
| 242 | |
| 243 | Returns a pointer on the current position of the stream buffer. |
| 244 | |
| 245 | \membersection{wxStreamBuffer::GetIntPosition} |
| 246 | |
| 247 | \constfunc{off\_t}{GetIntPosition}{\void} |
| 248 | |
| 249 | Returns the current position (counted in bytes) in the stream buffer. |
| 250 | |
| 251 | \membersection{wxStreamBuffer::SetIntPosition} |
| 252 | |
| 253 | \func{void}{SetIntPosition}{\param{size\_t}{ pos}} |
| 254 | |
| 255 | Sets the current position (in bytes) in the stream buffer. |
| 256 | |
| 257 | \wxheading{Warning} |
| 258 | |
| 259 | Since it is a very low-level function, there is no check on the position: |
| 260 | specifing an invalid position can induce unexpected results. |
| 261 | |
| 262 | \membersection{wxStreamBuffer::GetLastAccess} |
| 263 | |
| 264 | \constfunc{size\_t}{GetLastAccess}{\void} |
| 265 | |
| 266 | Returns the amount of bytes read during the last IO call to the parent stream. |
| 267 | |
| 268 | \membersection{wxStreamBuffer::Fixed}\label{wxstreambufferfixed} |
| 269 | |
| 270 | \func{void}{Fixed}{\param{bool}{ fixed}} |
| 271 | |
| 272 | Toggles the fixed flag. Usually this flag is toggled at the same time as |
| 273 | {\it flushable}. This flag allows (when it has the false value) or forbids |
| 274 | (when it has the true value) the stream buffer to resize dynamically the IO buffer. |
| 275 | |
| 276 | \wxheading{See also} |
| 277 | |
| 278 | \helpref{wxStreamBuffer::SetBufferIO}{wxstreambuffersetbufferio} |
| 279 | |
| 280 | \membersection{wxStreamBuffer::Flushable}\label{wxstreambufferflushable} |
| 281 | |
| 282 | \func{void}{Flushable}{\param{bool}{ flushable}} |
| 283 | |
| 284 | Toggles the flushable flag. If {\it flushable} is disabled, no data are sent |
| 285 | to the parent stream. |
| 286 | |
| 287 | \membersection{wxStreamBuffer::FlushBuffer} |
| 288 | |
| 289 | \func{bool}{FlushBuffer}{\void} |
| 290 | |
| 291 | Flushes the IO buffer. |
| 292 | |
| 293 | \membersection{wxStreamBuffer::FillBuffer} |
| 294 | |
| 295 | \func{bool}{FillBuffer}{\void} |
| 296 | |
| 297 | Fill the IO buffer. |
| 298 | |
| 299 | \membersection{wxStreamBuffer::GetDataLeft} |
| 300 | |
| 301 | \func{size\_t}{GetDataLeft}{\void} |
| 302 | |
| 303 | Returns the amount of available data in the buffer. |
| 304 | |
| 305 | % -------------- |
| 306 | % Administration |
| 307 | % -------------- |
| 308 | \membersection{wxStreamBuffer::Stream} |
| 309 | |
| 310 | \func{wxStreamBase*}{Stream}{\void} |
| 311 | |
| 312 | Returns the parent stream of the stream buffer. |
| 313 | |