classpmemoryfile.html

pwlib开发文档

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<a name="z487_0" doxytag="PMemoryFile::Read"></a><p>
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          <td class="md" nowrap valign="top"> virtual BOOL PMemoryFile::Read </td>
          <td class="md" valign="top">(&nbsp;</td>
          <td class="md" nowrap valign="top">void *&nbsp;</td>
          <td class="mdname" nowrap>&nbsp; <em>buf</em>, </td>
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          <td></td>
          <td></td>
          <td class="md" nowrap>PINDEX&nbsp;</td>
          <td class="mdname" nowrap>&nbsp; <em>len</em></td>
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          <td class="md">)&nbsp;</td>
          <td class="md" colspan="2"><code> [virtual]</code></td>
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<p>
Low level read from the memory file channel. The read timeout is ignored. The <a class="el" href="classPChannel.html#z49_3">GetLastReadCount()</a> function returns the actual number of bytes read.
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The <a class="el" href="classPChannel.html#z55_2">GetErrorCode()</a> function should be consulted after <a class="el" href="classPMemoryFile.html#z487_0">Read()</a> returns FALSE to determine what caused the failure.
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<dl compact><dt><b>Returns: </b></dt><dd>
 TRUE indicates that at least one character was read from the channel. FALSE means no bytes were read due to timeout or some other I/O error. </dl><dl compact><dt><b>Parameters: </b></dt><dd>
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<tr><td valign=top><em>len</em>&nbsp;</td><td>
Pointer to a block of memory to receive the read bytes. Maximum number of bytes to read into the buffer. </td></tr>
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Reimplemented from <a class="el" href="classPFile.html#z129_1">PFile</a>.    </td>
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<a name="z489_1" doxytag="PMemoryFile::SetLength"></a><p>
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          <td class="md" nowrap valign="top"> BOOL PMemoryFile::SetLength </td>
          <td class="md" valign="top">(&nbsp;</td>
          <td class="md" nowrap valign="top">off_t&nbsp;</td>
          <td class="mdname1" valign="top" nowrap>&nbsp; <em>len</em>          </td>
          <td class="md" valign="top">)&nbsp;</td>
          <td class="md" nowrap><code> [virtual]</code></td>
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Set the size of the file, padding with 0 bytes if it would require expanding the file, or truncating it if being made shorter.
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<dl compact><dt><b>Returns: </b></dt><dd>
 TRUE if the file size was changed to the length specified. </dl>
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Reimplemented from <a class="el" href="classPFile.html#z133_6">PFile</a>.    </td>
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<a name="z489_2" doxytag="PMemoryFile::SetPosition"></a><p>
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          <td class="md" nowrap valign="top"> BOOL PMemoryFile::SetPosition </td>
          <td class="md" valign="top">(&nbsp;</td>
          <td class="md" nowrap valign="top">off_t&nbsp;</td>
          <td class="mdname" nowrap>&nbsp; <em>pos</em>, </td>
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          <td class="md" nowrap><a class="el" href="classPFile.html#z133_0">FilePositionOrigin</a>&nbsp;</td>
          <td class="mdname" nowrap>&nbsp; <em>origin</em> = Start</td>
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          <td class="md">)&nbsp;</td>
          <td class="md" colspan="2"><code> [virtual]</code></td>
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<p>
Set the current active position in the file for the next read or write operation. The pos# variable is a signed number which is added to the specified origin. For origin == <a class="el" href="classPFile.html#z133_0s11">PFile::Start</a># only positive values for pos# are meaningful. For origin == <a class="el" href="classPFile.html#z133_0s13">PFile::End</a># only negative values for pos# are meaningful.
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<dl compact><dt><b>Returns: </b></dt><dd>
 TRUE if the new file position was set. </dl><dl compact><dt><b>Parameters: </b></dt><dd>
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New position to set. Origin for position change. </td></tr>
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Reimplemented from <a class="el" href="classPFile.html#z133_7">PFile</a>.    </td>
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<a name="z487_1" doxytag="PMemoryFile::Write"></a><p>
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          <td class="md" nowrap valign="top"> virtual BOOL PMemoryFile::Write </td>
          <td class="md" valign="top">(&nbsp;</td>
          <td class="md" nowrap valign="top">const void *&nbsp;</td>
          <td class="mdname" nowrap>&nbsp; <em>buf</em>, </td>
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          <td></td>
          <td></td>
          <td class="md" nowrap>PINDEX&nbsp;</td>
          <td class="mdname" nowrap>&nbsp; <em>len</em></td>
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          <td class="md">)&nbsp;</td>
          <td class="md" colspan="2"><code> [virtual]</code></td>
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<p>
Low level write to the memory file channel. The write timeout is ignored. The <a class="el" href="classPChannel.html#z51_3">GetLastWriteCount()</a> function returns the actual number of bytes written.
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The <a class="el" href="classPChannel.html#z55_2">GetErrorCode()</a> function should be consulted after <a class="el" href="classPMemoryFile.html#z487_1">Write()</a> returns FALSE to determine what caused the failure.
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<dl compact><dt><b>Returns: </b></dt><dd>
TRUE if at least len bytes were written to the channel. </dl><dl compact><dt><b>Parameters: </b></dt><dd>
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Pointer to a block of memory to write. Number of bytes to write. </td></tr>
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Reimplemented from <a class="el" href="classPFile.html#z129_2">PFile</a>.    </td>
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<hr><h2>Member Data Documentation</h2>
<a name="n0" doxytag="PMemoryFile::data"></a><p>
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          <td class="md" nowrap valign="top"> <a class="el" href="classPBYTEArray.html">PBYTEArray</a> PMemoryFile::data<code> [protected]</code>
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<a name="n1" doxytag="PMemoryFile::position"></a><p>
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          <td class="md" nowrap valign="top"> off_t PMemoryFile::position<code> [protected]</code>
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<hr>The documentation for this class was generated from the following file:<ul>
<li><a class="el" href="memfile_8h-source.html">memfile.h</a></ul>
<hr><address style="align: right;"><small>Generated on Wed Sep 29 22:44:17 2004 for PWLib by
<a href="http://www.doxygen.org/index.html">
<img src="doxygen.png" alt="doxygen" align="middle" border=0 
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