Lunchbox  1.4.0
lfQueue.h
00001 
00002 /* Copyright (c) 2010-2012, 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 LUNCHBOX_LFQUEUE_H
00019 #define LUNCHBOX_LFQUEUE_H
00020 
00021 #include <lunchbox/atomic.h> // member
00022 #include <lunchbox/debug.h>  // used in inline method
00023 #include <lunchbox/nonCopyable.h>  // base class
00024 #include <lunchbox/thread.h> // thread-safety checks
00025 
00026 #include <vector>
00027 
00028 namespace lunchbox
00029 {
00044     template< typename T > class LFQueue : public NonCopyable
00045     {
00046     public:
00048         LFQueue( const int32_t size )
00049                 : _data( size + 1 ), _readPos( 0 ), _writePos( 0 ) {}
00050 
00052         ~LFQueue() {}
00053 
00055         bool isEmpty() const { return _readPos == _writePos; }
00056 
00058         void clear()
00059             {
00060                 LB_TS_SCOPED( _reader );
00061                 _readPos = 0;
00062                 _writePos = 0;
00063             }
00064             
00071         void resize( const int32_t size )
00072             {
00073                 LBASSERT( isEmpty( ));
00074                 _readPos = 0;
00075                 _writePos = 0;
00076                 _data.resize( size + 1 );
00077             }
00078 
00087         bool pop( T& result )
00088             {
00089                 LB_TS_SCOPED( _reader );
00090                 if( _readPos == _writePos )
00091                     return false;
00092                 
00093                 result = _data[ _readPos ];
00094                 _readPos = (_readPos + 1) % _data.size();
00095                 return true;
00096             }
00097 
00106         bool getFront( T& result )
00107             {
00108                 LB_TS_SCOPED( _reader );
00109                 if( _readPos == _writePos )
00110                     return false;
00111                 
00112                 result = _data[ _readPos ];
00113                 return true;
00114             }
00115 
00123         bool push( const T& element )
00124             {
00125                 LB_TS_SCOPED( _writer );
00126                 int32_t nextPos = (_writePos + 1) % _data.size();
00127                 if( nextPos == _readPos )
00128                     return false;
00129 
00130                 _data[ _writePos ] = element;
00131                 _writePos = nextPos;
00132                 return true;
00133             }
00134 
00139         size_t getCapacity() const { return _data.size() - 1; }
00140 
00141     private:
00142         std::vector< T > _data;
00143         a_int32_t _readPos;
00144         a_int32_t _writePos;
00145 
00146         LB_TS_VAR( _reader );
00147         LB_TS_VAR( _writer );
00148     };
00149 }
00150 #endif // LUNCHBOX_LFQUEUE_H