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secondo/Algebras/Parallel/SyncStream.h
2026-01-23 17:03:45 +08:00

89 lines
1.9 KiB
C++

/*
----
This file is part of SECONDO.
Copyright (C) 2019,
University in Hagen,
Faculty of Mathematics and Computer Science,
Database Systems for New Applications.
SECONDO is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
SECONDO is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with SECONDO; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
----
*/
#pragma once
#include "Stream.h"
template<class T>
class SyncStream{
public:
SyncStream(Word& w) : stream(w), endReached(true){}
~SyncStream(){
}
void open(){
boost::lock_guard<boost::mutex> guard(mtx);
endReached = false;
stream.open();
}
void close(){
boost::lock_guard<boost::mutex> guard(mtx);
endReached = true;
stream.close();
}
T* request(){
boost::lock_guard<boost::mutex> guard(mtx);
T* res;
if(endReached){
res = 0;
} else {
res = stream.request();
if(res==0){
endReached = true;
}
}
return res;
}
void request(std::vector<T*>& buffer, int elems){
boost::lock_guard<boost::mutex> guard(mtx);
buffer.clear();
if(endReached){
buffer.push_back(nullptr);
return;
}
for( int i=0;i<elems && !endReached; i++){
T* res = stream.request();
if(res==0){
endReached = true;
}
buffer.push_back(res);
}
}
private:
Stream<T> stream;
bool endReached;
boost::mutex mtx;
};