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<hr><h1>ost::MappedFile Class Reference</h1>Create and map a disk file into memory. Map a named disk file into memory.
<a href="#_details">More...</a>
<p>
<code>#include <<a class="el" href="file_8h-source.html">file.h</a>></code>
<p>
<p>Inheritance diagram for ost::MappedFile::
<p><center><img src="classost_1_1_mapped_file.gif" usemap="#ost::MappedFile_map" border="0"></center>
<map name="ost::MappedFile_map">
<area href="classost_1_1_random_file.html" alt="ost::RandomFile" shape="rect" coords="0,56,101,80">
<area href="classost_1_1_mutex.html" alt="ost::Mutex" shape="rect" coords="0,0,101,24">
</map>
<a href="classost_1_1_mapped_file-members.html">List of all members.</a><table border=0 cellpadding=0 cellspacing=0>
<tr><td colspan=2><br><h2>Public Methods</h2></td></tr>
<tr><td nowrap align=right valign=top> </td><td valign=bottom><a class="el" href="classost_1_1_mapped_file.html#a0">MappedFile</a> (const char *fname, <a class="el" href="namespaceost.html#a6">fileaccess_t</a> mode)</td></tr>
<tr><td> </td><td><font size=-1><em>Open a file for mapping.</em> <a href="#a0">More...</a><em></em></font><br><br></td></tr>
<tr><td nowrap align=right valign=top> </td><td valign=bottom><a class="el" href="classost_1_1_mapped_file.html#a1">MappedFile</a> (const char *fname, <a class="el" href="namespaceost.html#a1">pos_t</a> offset, size_t size, <a class="el" href="namespaceost.html#a6">fileaccess_t</a> mode)</td></tr>
<tr><td> </td><td><font size=-1><em>Map a portion or all of a specified file in the specified shared memory access mode.</em> <a href="#a1">More...</a><em></em></font><br><br></td></tr>
<tr><td nowrap align=right valign=top>virtual </td><td valign=bottom><a class="el" href="classost_1_1_mapped_file.html#a2">~MappedFile</a> ()</td></tr>
<tr><td> </td><td><font size=-1><em>Release a mapped section of memory associated with a file.</em> <a href="#a2">More...</a><em></em></font><br><br></td></tr>
<tr><td nowrap align=right valign=top>void </td><td valign=bottom><a class="el" href="classost_1_1_mapped_file.html#a3">Sync</a> (void)</td></tr>
<tr><td> </td><td><font size=-1><em>Synchronize the contents of the mapped portion of memory with the disk file and wait for completion.</em> <a href="#a3">More...</a><em></em></font><br><br></td></tr>
<tr><td nowrap align=right valign=top>void </td><td valign=bottom><a class="el" href="classost_1_1_mapped_file.html#a4">Sync</a> (char *address, size_t len)</td></tr>
<tr><td> </td><td><font size=-1><em>Synchronize a segment of memory mapped from a segment fetch.</em> <a href="#a4">More...</a><em></em></font><br><br></td></tr>
<tr><td nowrap align=right valign=top>void </td><td valign=bottom><a class="el" href="classost_1_1_mapped_file.html#a5">Update</a> (size_t offset=0, size_t len=0)</td></tr>
<tr><td> </td><td><font size=-1><em>Map a portion of the memory mapped from the file back to the file and do not wait for completion.</em> <a href="#a5">More...</a><em></em></font><br><br></td></tr>
<tr><td nowrap align=right valign=top>void </td><td valign=bottom><a class="el" href="classost_1_1_mapped_file.html#a6">Update</a> (char *address, size_t len)</td></tr>
<tr><td> </td><td><font size=-1><em>Update a mapped region back to disk as specified by address and length.</em> <a href="#a6">More...</a><em></em></font><br><br></td></tr>
<tr><td nowrap align=right valign=top>void </td><td valign=bottom><a class="el" href="classost_1_1_mapped_file.html#a7">Release</a> (char *address, size_t len)</td></tr>
<tr><td> </td><td><font size=-1><em>Release (unmap) a memory segment.</em> <a href="#a7">More...</a><em></em></font><br><br></td></tr>
<tr><td nowrap align=right valign=top>char * </td><td valign=bottom><a class="el" href="classost_1_1_mapped_file.html#a8">Fetch</a> (size_t offset=0)</td></tr>
<tr><td> </td><td><font size=-1><em>Fetch a pointer to an offset within the memory mapped portion of the disk file.</em> <a href="#a8">More...</a><em></em></font><br><br></td></tr>
<tr><td nowrap align=right valign=top>char * </td><td valign=bottom><a class="el" href="classost_1_1_mapped_file.html#a9">Fetch</a> (off_t pos, size_t len)</td></tr>
<tr><td> </td><td><font size=-1><em>Fetch and map a portion of a disk file to a logical memory block.</em> <a href="#a9">More...</a><em></em></font><br><br></td></tr>
</table>
<hr><a name="_details"></a><h2>Detailed Description</h2>
Create and map a disk file into memory. Map a named disk file into memory.
<p>
This portable class works under both Posix via mmap and under the win32 API. A mapped file can be referenced directly by it's memory segment. One can map and unmap portions of a file on demand, and update changed memory pages mapped from files immediately through sync().
<p>
<dl compact><dt><b>
Author: </b><dd>
David Sugar <<a href="mailto:dyfet@ostel.com">dyfet@ostel.com</a>> </dl>
<p>
<hr><h2>Constructor & Destructor Documentation</h2>
<a name="a0" doxytag="ost::MappedFile::MappedFile"></a><p>
<table width="100%" cellpadding="2" cellspacing="0" border="0">
<tr>
<td class="md">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top"> ost::MappedFile::MappedFile </td>
<td class="md">( </td>
<td class="md">const char *</td>
<td class="mdname"> <em>fname</em>, </td>
</tr>
<tr>
<td></td>
<td></td>
<td class="md"><a class="el" href="namespaceost.html#a6">fileaccess_t</a></td>
<td class="mdname"> <em>mode</em></td>
</tr>
<tr>
<td></td>
<td class="md">) </td>
<td class="md" colspan="2"></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing=5 cellpadding=0 border=0>
<tr>
<td>
</td>
<td>
<p>
Open a file for mapping.
<p>
More than one segment of a file may be mapped into seperate regions of memory.<dl compact><dt><b>
Parameters: </b><dd>
<table border=0 cellspacing=2 cellpadding=0>
<tr><td valign=top><em>file
</em> </td><td>
name to access for mapping. </td></tr>
<tr><td valign=top><em>access
</em> </td><td>
mode to map file. </td></tr>
</table>
</dl> </td>
</tr>
</table>
<a name="a1" doxytag="ost::MappedFile::MappedFile"></a><p>
<table width="100%" cellpadding="2" cellspacing="0" border="0">
<tr>
<td class="md">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top"> ost::MappedFile::MappedFile </td>
<td class="md">( </td>
<td class="md">const char *</td>
<td class="mdname"> <em>fname</em>, </td>
</tr>
<tr>
<td></td>
<td></td>
<td class="md"><a class="el" href="namespaceost.html#a1">pos_t</a></td>
<td class="mdname"> <em>offset</em>, </td>
</tr>
<tr>
<td></td>
<td></td>
<td class="md">size_t</td>
<td class="mdname"> <em>size</em>, </td>
</tr>
<tr>
<td></td>
<td></td>
<td class="md"><a class="el" href="namespaceost.html#a6">fileaccess_t</a></td>
<td class="mdname"> <em>mode</em></td>
</tr>
<tr>
<td></td>
<td class="md">) </td>
<td class="md" colspan="2"></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing=5 cellpadding=0 border=0>
<tr>
<td>
</td>
<td>
<p>
Map a portion or all of a specified file in the specified shared memory access mode.
<p>
Valid mapping modes include FILE_MAPPED_READ, FILE_MAPPED_WRITE, and FILE_MAPPED_RDWR.<dl compact><dt><b>
Parameters: </b><dd>
<table border=0 cellspacing=2 cellpadding=0>
<tr><td valign=top><em>fname
</em> </td><td>
pathname of file to map into memory. </td></tr>
<tr><td valign=top><em>offset
</em> </td><td>
from start of file to begin mapping in bytes. </td></tr>
<tr><td valign=top><em>size
</em> </td><td>
of mapped area in bytes. </td></tr>
<tr><td valign=top><em>mode
</em> </td><td>
to map file. </td></tr>
</table>
</dl> </td>
</tr>
</table>
<a name="a2" doxytag="ost::MappedFile::~MappedFile"></a><p>
<table width="100%" cellpadding="2" cellspacing="0" border="0">
<tr>
<td class="md">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top"> virtual ost::MappedFile::~MappedFile </td>
<td class="md">( </td>
<td class="mdname1"> </td>
<td class="md">) </td>
<td class="md"><code> [virtual]</code></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing=5 cellpadding=0 border=0>
<tr>
<td>
</td>
<td>
<p>
Release a mapped section of memory associated with a file.
<p>
The mapped area is updated back to disk. </td>
</tr>
</table>
<hr><h2>Member Function Documentation</h2>
<a name="a9" doxytag="ost::MappedFile::Fetch"></a><p>
<table width="100%" cellpadding="2" cellspacing="0" border="0">
<tr>
<td class="md">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top"> char* ost::MappedFile::Fetch </td>
<td class="md">( </td>
<td class="md">off_t</td>
<td class="mdname"> <em>pos</em>, </td>
</tr>
<tr>
<td></td>
<td></td>
<td class="md">size_t</td>
<td class="mdname"> <em>len</em></td>
</tr>
<tr>
<td></td>
<td class="md">) </td>
<td class="md" colspan="2"></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing=5 cellpadding=0 border=0>
<tr>
<td>
</td>
<td>
<p>
Fetch and map a portion of a disk file to a logical memory block.
<p>
<dl compact><dt><b>
Returns: </b><dd>
pointer to memory segment. </dl><dl compact><dt><b>
Parameters: </b><dd>
<table border=0 cellspacing=2 cellpadding=0>
<tr><td valign=top><em>offset
</em> </td><td>
of file segment to map. </td></tr>
<tr><td valign=top><em>size
</em> </td><td>
of memory segment to map. </td></tr>
</table>
</dl> </td>
</tr>
</table>
<a name="a8" doxytag="ost::MappedFile::Fetch"></a><p>
<table width="100%" cellpadding="2" cellspacing="0" border="0">
<tr>
<td class="md">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top"> char* ost::MappedFile::Fetch </td>
<td class="md">( </td>
<td class="md">size_t</td>
<td class="mdname1"> <em>offset</em> = 0 </td>
<td class="md">) </td>
<td class="md"><code> [inline]</code></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing=5 cellpadding=0 border=0>
<tr>
<td>
</td>
<td>
<p>
Fetch a pointer to an offset within the memory mapped portion of the disk file.
<p>
This really is used for convience of matching operations between Update and Fetch, as one could simply have accessed the base pointer where the file was mapped directly.<dl compact><dt><b>
Parameters: </b><dd>
<table border=0 cellspacing=2 cellpadding=0>
<tr><td valign=top><em>offset
</em> </td><td>
from start of mapped memory. </td></tr>
</table>
</dl> </td>
</tr>
</table>
<a name="a7" doxytag="ost::MappedFile::Release"></a><p>
<table width="100%" cellpadding="2" cellspacing="0" border="0">
<tr>
<td class="md">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top"> void ost::MappedFile::Release </td>
<td class="md">( </td>
<td class="md">char *</td>
<td class="mdname"> <em>address</em>, </td>
</tr>
<tr>
<td></td>
<td></td>
<td class="md">size_t</td>
<td class="mdname"> <em>len</em></td>
</tr>
<tr>
<td></td>
<td class="md">) </td>
<td class="md" colspan="2"></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing=5 cellpadding=0 border=0>
<tr>
<td>
</td>
<td>
<p>
Release (unmap) a memory segment.
<p>
<dl compact><dt><b>
Parameters: </b><dd>
<table border=0 cellspacing=2 cellpadding=0>
<tr><td valign=top><em>address
</em> </td><td>
of memory segment to release. </td></tr>
<tr><td valign=top><em>length
</em> </td><td>
of memory segment to release. </td></tr>
</table>
</dl> </td>
</tr>
</table>
<a name="a4" doxytag="ost::MappedFile::Sync"></a><p>
<table width="100%" cellpadding="2" cellspacing="0" border="0">
<tr>
<td class="md">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top"> void ost::MappedFile::Sync </td>
<td class="md">( </td>
<td class="md">char *</td>
<td class="mdname"> <em>address</em>, </td>
</tr>
<tr>
<td></td>
<td></td>
<td class="md">size_t</td>
<td class="mdname"> <em>len</em></td>
</tr>
<tr>
<td></td>
<td class="md">) </td>
<td class="md" colspan="2"></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing=5 cellpadding=0 border=0>
<tr>
<td>
</td>
<td>
<p>
Synchronize a segment of memory mapped from a segment fetch.
<p>
<dl compact><dt><b>
Parameters: </b><dd>
<table border=0 cellspacing=2 cellpadding=0>
<tr><td valign=top><em>memory
</em> </td><td>
address to update. </td></tr>
<tr><td valign=top><em>size
</em> </td><td>
of segment. </td></tr>
</table>
</dl> </td>
</tr>
</table>
<a name="a3" doxytag="ost::MappedFile::Sync"></a><p>
<table width="100%" cellpadding="2" cellspacing="0" border="0">
<tr>
<td class="md">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top"> void ost::MappedFile::Sync </td>
<td class="md">( </td>
<td class="md">void</td>
<td class="mdname1"> </td>
<td class="md">) </td>
<td class="md"><code> [inline]</code></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing=5 cellpadding=0 border=0>
<tr>
<td>
</td>
<td>
<p>
Synchronize the contents of the mapped portion of memory with the disk file and wait for completion.
<p>
This assures the memory mapped from the file is written back. </td>
</tr>
</table>
<a name="a6" doxytag="ost::MappedFile::Update"></a><p>
<table width="100%" cellpadding="2" cellspacing="0" border="0">
<tr>
<td class="md">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top"> void ost::MappedFile::Update </td>
<td class="md">( </td>
<td class="md">char *</td>
<td class="mdname"> <em>address</em>, </td>
</tr>
<tr>
<td></td>
<td></td>
<td class="md">size_t</td>
<td class="mdname"> <em>len</em></td>
</tr>
<tr>
<td></td>
<td class="md">) </td>
<td class="md" colspan="2"></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing=5 cellpadding=0 border=0>
<tr>
<td>
</td>
<td>
<p>
Update a mapped region back to disk as specified by address and length.
<p>
<dl compact><dt><b>
Parameters: </b><dd>
<table border=0 cellspacing=2 cellpadding=0>
<tr><td valign=top><em>address
</em> </td><td>
of segment. </td></tr>
<tr><td valign=top><em>length
</em> </td><td>
of segment. </td></tr>
</table>
</dl> </td>
</tr>
</table>
<a name="a5" doxytag="ost::MappedFile::Update"></a><p>
<table width="100%" cellpadding="2" cellspacing="0" border="0">
<tr>
<td class="md">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top"> void ost::MappedFile::Update </td>
<td class="md">( </td>
<td class="md">size_t</td>
<td class="mdname"> <em>offset</em> = 0, </td>
</tr>
<tr>
<td></td>
<td></td>
<td class="md">size_t</td>
<td class="mdname"> <em>len</em> = 0</td>
</tr>
<tr>
<td></td>
<td class="md">) </td>
<td class="md" colspan="2"></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing=5 cellpadding=0 border=0>
<tr>
<td>
</td>
<td>
<p>
Map a portion of the memory mapped from the file back to the file and do not wait for completion.
<p>
This is useful when mapping a database file and updating a single record.<dl compact><dt><b>
Parameters: </b><dd>
<table border=0 cellspacing=2 cellpadding=0>
<tr><td valign=top><em>offset
</em> </td><td>
into the mapped region of memory. </td></tr>
<tr><td valign=top><em>len
</em> </td><td>
of partial region (example, record length). </td></tr>
</table>
</dl> </td>
</tr>
</table>
<hr>The documentation for this class was generated from the following file:<ul>
<li><a class="el" href="file_8h-source.html">file.h</a></ul>
<hr><address><small>Generated at Fri Jan 4 18:51:49 2002 for CommonC++ by
<a href="http://www.doxygen.org/index.html">
<img src="doxygen.gif" alt="doxygen" align="middle" border=0
width=110 height=53></a>1.2.10 written by <a href="mailto:dimitri@stack.nl">Dimitri van Heesch</a>,
© 1997-2001</small></address>
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