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<hr><h1>shared_memory.cpp</h1><a href="shared__memory_8cpp.html">Go to the documentation of this file.</a><div class="fragment"><pre>00001
00007 <font class="comment">/* Copyright, 2000-2002 Nevrax Ltd.</font>
00008 <font class="comment"> *</font>
00009 <font class="comment"> * This file is part of NEVRAX NEL.</font>
00010 <font class="comment"> * NEVRAX NEL is free software; you can redistribute it and/or modify</font>
00011 <font class="comment"> * it under the terms of the GNU General Public License as published by</font>
00012 <font class="comment"> * the Free Software Foundation; either version 2, or (at your option)</font>
00013 <font class="comment"> * any later version.</font>
00014 <font class="comment"></font>
00015 <font class="comment"> * NEVRAX NEL is distributed in the hope that it will be useful, but</font>
00016 <font class="comment"> * WITHOUT ANY WARRANTY; without even the implied warranty of</font>
00017 <font class="comment"> * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU</font>
00018 <font class="comment"> * General Public License for more details.</font>
00019 <font class="comment"></font>
00020 <font class="comment"> * You should have received a copy of the GNU General Public License</font>
00021 <font class="comment"> * along with NEVRAX NEL; see the file COPYING. If not, write to the</font>
00022 <font class="comment"> * Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,</font>
00023 <font class="comment"> * MA 02111-1307, USA.</font>
00024 <font class="comment"> */</font>
00025
00026 <font class="preprocessor">#include "<a class="code" href="stdmisc_8h.html">stdmisc.h</a>"</font>
00027 <font class="preprocessor">#include "<a class="code" href="shared__memory_8h.html">nel/misc/shared_memory.h</a>"</font>
00028
00029 <font class="preprocessor">#ifdef NL_OS_WINDOWS</font>
00030 <font class="preprocessor"></font><font class="preprocessor">#include <windows.h></font>
00031 <font class="preprocessor">#else</font>
00032 <font class="preprocessor"></font><font class="preprocessor"># include <sys/types.h></font>
00033 <font class="preprocessor"># include <sys/ipc.h></font>
00034 <font class="preprocessor"># include <sys/shm.h></font>
00035 <font class="preprocessor">#endif</font>
00036 <font class="preprocessor"></font>
00037 <font class="keyword">using</font> <font class="keyword">namespace </font>std;
00038
00039
00040 <font class="keyword">namespace </font>NLMISC {
00041
00042
00043 <font class="preprocessor">#ifdef NL_OS_WINDOWS</font>
00044 <font class="preprocessor"></font> <font class="comment">// Storage for file handles, necessary to close the handles</font>
00045 map<void*,HANDLE> AccessAddressesToHandles;
00046 <font class="preprocessor">#else</font>
00047 <font class="preprocessor"></font> <font class="comment">// Storage for shmid, necessary to destroy the segments</font>
00048 map<TSharedMemId, int> <a class="code" href="namespaceNLMISC.html#a202">SharedMemIdsToShmids</a>;
00049 <font class="preprocessor">#endif</font>
00050 <font class="preprocessor"></font>
00051
00052 <font class="comment">/*</font>
00053 <font class="comment"> * Create a shared memory segment</font>
00054 <font class="comment"> */</font>
<a name="l00055"></a><a class="code" href="classNLMISC_1_1CSharedMemory.html#d0">00055</a> <font class="keywordtype">void</font> *CSharedMemory::createSharedMemory( <a class="code" href="namespaceNLMISC.html#a176">TSharedMemId</a> sharedMemId, uint32 size )
00056 {
00057 <font class="preprocessor">#ifdef NL_OS_WINDOWS</font>
00058 <font class="preprocessor"></font>
00059 <font class="comment">// Create a file mapping backed by the virtual memory swap file (not a data file)</font>
00060 HANDLE hMapFile = CreateFileMapping( INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, 0, size, sharedMemId );
00061 <font class="keywordflow">if</font> ( (hMapFile == NULL) || (GetLastError() == ERROR_ALREADY_EXISTS) )
00062 <font class="keywordflow">return</font> NULL;
00063
00064 <font class="comment">// Map the file into memory address space</font>
00065 <font class="keywordtype">void</font> *accessAddress = MapViewOfFile( hMapFile, FILE_MAP_ALL_ACCESS, 0, 0, 0 );
00066 AccessAddressesToHandles.insert( make_pair( accessAddress, hMapFile ) );
00067 <font class="keywordflow">return</font> accessAddress;
00068
00069 <font class="preprocessor">#else</font>
00070 <font class="preprocessor"></font>
00071 <font class="comment">// Create a shared memory segment</font>
00072 <font class="keywordtype">int</font> shmid = shmget( sharedMemId, size, IPC_CREAT | IPC_EXCL | 0666 );
00073 <font class="keywordflow">if</font> ( shmid == -1 )
00074 <font class="keywordflow">return</font> NULL;
00075 <a class="code" href="namespaceNLMISC.html#a202">SharedMemIdsToShmids</a>.insert( make_pair( sharedMemId, shmid ) );
00076
00077 <font class="comment">// Map the segment into memory address space</font>
00078 <font class="keywordtype">void</font> *accessAddress = (<font class="keywordtype">void</font>*)shmat( shmid, 0, 0 );
00079 <font class="keywordflow">if</font> ( accessAddress == (<font class="keywordtype">void</font>*)-1 )
00080 <font class="keywordflow">return</font> NULL;
00081 <font class="keywordflow">else</font>
00082 <font class="keywordflow">return</font> accessAddress;
00083 <font class="preprocessor">#endif</font>
00084 <font class="preprocessor"></font>}
00085
00086
00087 <font class="comment">/*</font>
00088 <font class="comment"> * Get access to an existing shared memory segment</font>
00089 <font class="comment"> */</font>
<a name="l00090"></a><a class="code" href="classNLMISC_1_1CSharedMemory.html#d1">00090</a> <font class="keywordtype">void</font> *CSharedMemory::accessSharedMemory( <a class="code" href="namespaceNLMISC.html#a176">TSharedMemId</a> sharedMemId )
00091 {
00092 <font class="preprocessor">#ifdef NL_OS_WINDOWS</font>
00093 <font class="preprocessor"></font>
00094 <font class="comment">// Open the existing file mapping by name</font>
00095 HANDLE hMapFile = OpenFileMapping( FILE_MAP_ALL_ACCESS, <font class="keyword">false</font>, sharedMemId );
00096 <font class="keywordflow">if</font> ( hMapFile == NULL )
00097 <font class="keywordflow">return</font> NULL;
00098
00099 <font class="comment">// Map the file into memory address space</font>
00100 <font class="keywordtype">void</font> *accessAddress = MapViewOfFile( hMapFile, FILE_MAP_ALL_ACCESS, 0, 0, 0 );
00101 AccessAddressesToHandles.insert( make_pair( accessAddress, hMapFile ) );
00102 <font class="keywordflow">return</font> accessAddress;
00103
00104 <font class="preprocessor">#else</font>
00105 <font class="preprocessor"></font>
00106 <font class="comment">// Open an existing shared memory segment</font>
00107 <font class="keywordtype">int</font> shmid = shmget( sharedMemId, 0, 0666 );
00108 <font class="keywordflow">if</font> ( shmid == -1 )
00109 <font class="keywordflow">return</font> NULL;
00110
00111 <font class="comment">// Map the segment into memory address space</font>
00112 <font class="keywordtype">void</font> *accessAddress = (<font class="keywordtype">void</font>*)shmat( shmid, 0, 0 );
00113 <font class="keywordflow">if</font> ( accessAddress == (<font class="keywordtype">void</font>*)-1 )
00114 <font class="keywordflow">return</font> NULL;
00115 <font class="keywordflow">else</font>
00116 <font class="keywordflow">return</font> accessAddress;
00117
00118 <font class="preprocessor">#endif</font>
00119 <font class="preprocessor"></font>}
00120
00121
00122 <font class="comment">/*</font>
00123 <font class="comment"> * Close a shared memory segment</font>
00124 <font class="comment"> */</font>
<a name="l00125"></a><a class="code" href="classNLMISC_1_1CSharedMemory.html#d2">00125</a> <font class="keywordtype">bool</font> CSharedMemory::closeSharedMemory( <font class="keywordtype">void</font> *accessAddress )
00126 {
00127 <font class="preprocessor">#ifdef NL_OS_WINDOWS</font>
00128 <font class="preprocessor"></font>
00129 <font class="comment">// Unmap the file from memory address space</font>
00130 <font class="keywordflow">if</font> ( UnmapViewOfFile( accessAddress ) == 0 )
00131 <font class="keywordflow">return</font> <font class="keyword">false</font>;
00132
00133 <font class="comment">// Close the corresponding handle</font>
00134 map<void*,HANDLE>::iterator im = AccessAddressesToHandles.find( accessAddress );
00135 <font class="keywordflow">if</font> ( im != AccessAddressesToHandles.end() )
00136 {
00137 CloseHandle( (*im).second );
00138 AccessAddressesToHandles.erase( im );
00139 <font class="keywordflow">return</font> <font class="keyword">true</font>;
00140 }
00141 <font class="keywordflow">else</font>
00142 {
00143 <font class="keywordflow">return</font> <font class="keyword">false</font>;
00144 }
00145
00146 <font class="preprocessor">#else</font>
00147 <font class="preprocessor"></font>
00148 <font class="comment">// Detach the shared memory segment</font>
00149 <font class="keywordflow">return</font> ( shmdt( accessAddress ) != -1 );
00150
00151 <font class="preprocessor">#endif</font>
00152 <font class="preprocessor"></font>}
00153
00154
00155 <font class="comment">/*</font>
00156 <font class="comment"> * Destroy a shared memory segment (to call only by the process that created the segment)</font>
00157 <font class="comment"> * Note: does nothing under Windows, it is automatic.</font>
00158 <font class="comment"> */</font>
<a name="l00159"></a><a class="code" href="classNLMISC_1_1CSharedMemory.html#d3">00159</a> <font class="keywordtype">void</font> CSharedMemory::destroySharedMemory( <a class="code" href="namespaceNLMISC.html#a176">TSharedMemId</a> sharedMemId, <font class="keywordtype">bool</font> force )
00160 {
00161 <font class="preprocessor">#ifndef NL_OS_WINDOWS</font>
00162 <font class="preprocessor"></font> <font class="comment">// Set the segment to auto-destroying (when the last process detaches)</font>
00163 map<TSharedMemId,int>::iterator im = <a class="code" href="namespaceNLMISC.html#a202">SharedMemIdsToShmids</a>.find( sharedMemId );
00164 <font class="keywordflow">if</font> ( im != <a class="code" href="namespaceNLMISC.html#a202">SharedMemIdsToShmids</a>.end() )
00165 {
00166 <font class="comment">// Destroy the segment created before</font>
00167 shmctl( (*im).second, IPC_RMID, 0 );
00168 <a class="code" href="namespaceNLMISC.html#a202">SharedMemIdsToShmids</a>.erase( im );
00169 }
00170 <font class="keywordflow">else</font> <font class="keywordflow">if</font> ( force )
00171 {
00172 <font class="comment">// Open and destroy the segment</font>
00173 <font class="keywordtype">int</font> shmid = shmget( sharedMemId, 0, 0666 );
00174 <font class="keywordflow">if</font> ( shmid != -1 )
00175 {
00176 <font class="comment">// Destroy the segment</font>
00177 shmctl( shmid, IPC_RMID, 0 );
00178 }
00179 }
00180 <font class="preprocessor">#endif</font>
00181 <font class="preprocessor"></font>}
00182
00183
00184 } <font class="comment">// NLMISC</font>
</pre></div>
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