Equalizer  1.2.1
lfQueue.h
00001 
00002 /* Copyright (c) 2010, Stefan Eilemann <eile@equalizergraphics.com> 
00003  *
00004  * This library is free software; you can redistribute it and/or modify it under
00005  * the terms of the GNU Lesser General Public License version 2.1 as published
00006  * by the Free Software Foundation.
00007  *  
00008  * This library is distributed in the hope that it will be useful, but WITHOUT
00009  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
00010  * FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
00011  * details.
00012  * 
00013  * You should have received a copy of the GNU Lesser General Public License
00014  * along with this library; if not, write to the Free Software Foundation, Inc.,
00015  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
00016  */
00017 
00018 #ifndef COBASE_LFQUEUE_H
00019 #define COBASE_LFQUEUE_H
00020 
00021 #include <co/base/atomic.h> // member
00022 #include <co/base/debug.h>  // used in inline method
00023 #include <co/base/nonCopyable.h>  // base class
00024 #include <co/base/thread.h> // thread-safety checks
00025 
00026 #include <vector>
00027 
00028 namespace co
00029 {
00030 namespace base
00031 {
00046     template< typename T > class LFQueue : public NonCopyable
00047     {
00048     public:
00050         LFQueue( const int32_t size )
00051                 : _data( size + 1 ), _readPos( 0 ), _writePos( 0 ) {}
00052 
00054         ~LFQueue() {}
00055 
00057         bool isEmpty() const { return _readPos == _writePos; }
00058 
00060         void clear()
00061             {
00062                 EQ_TS_SCOPED( _reader );
00063                 _readPos = 0;
00064                 _writePos = 0;
00065             }
00066             
00073         void resize( const int32_t size )
00074             {
00075                 EQASSERT( isEmpty( ));
00076                 _readPos = 0;
00077                 _writePos = 0;
00078                 _data.resize( size + 1 );
00079             }
00080 
00089         bool pop( T& result )
00090             {
00091                 EQ_TS_SCOPED( _reader );
00092                 if( _readPos == _writePos )
00093                     return false;
00094                 
00095                 result = _data[ _readPos ];
00096                 _readPos = (_readPos + 1) % _data.size();
00097                 return true;
00098             }
00099 
00108         bool getFront( T& result )
00109             {
00110                 EQ_TS_SCOPED( _reader );
00111                 if( _readPos == _writePos )
00112                     return false;
00113                 
00114                 result = _data[ _readPos ];
00115                 return true;
00116             }
00117 
00125         bool push( const T& element )
00126             {
00127                 EQ_TS_SCOPED( _writer );
00128                 int32_t nextPos = (_writePos + 1) % _data.size();
00129                 if( nextPos == _readPos )
00130                     return false;
00131 
00132                 _data[ _writePos ] = element;
00133                 _writePos = nextPos;
00134                 return true;
00135             }
00136 
00141         size_t getCapacity() const { return _data.size() - 1; }
00142 
00143     private:
00144         std::vector< T > _data;
00145         a_int32_t _readPos;
00146         a_int32_t _writePos;
00147 
00148         EQ_TS_VAR( _reader );
00149         EQ_TS_VAR( _writer );
00150     };
00151 
00152 }
00153 }
00154 #endif // COBASE_LFQUEUE_H
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