PLearn 0.1
MRUFileList.cc
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00001 // -*- C++ -*-
00002 
00003 // PLearn (A C++ Machine Learning Library)
00004 // Copyright (C) 1998 Pascal Vincent
00005 // Copyright (C) 1999-2002 Pascal Vincent, Yoshua Bengio and University of Montreal
00006 //
00007 
00008 // Redistribution and use in source and binary forms, with or without
00009 // modification, are permitted provided that the following conditions are met:
00010 // 
00011 //  1. Redistributions of source code must retain the above copyright
00012 //     notice, this list of conditions and the following disclaimer.
00013 // 
00014 //  2. Redistributions in binary form must reproduce the above copyright
00015 //     notice, this list of conditions and the following disclaimer in the
00016 //     documentation and/or other materials provided with the distribution.
00017 // 
00018 //  3. The name of the authors may not be used to endorse or promote
00019 //     products derived from this software without specific prior written
00020 //     permission.
00021 // 
00022 // THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
00023 // IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
00024 // OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
00025 // NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
00026 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
00027 // TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
00028 // PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
00029 // LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
00030 // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
00031 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00032 // 
00033 // This file is part of the PLearn library. For more information on the PLearn
00034 // library, go to the PLearn Web site at www.plearn.org
00035 
00036 #include <string>
00037 
00038 #include "MRUFileList.h"
00039 
00040 namespace PLearn {
00041 
00042 MRUFileList::MRUFileList(int _max_opened_files, ios_base::openmode _mode)
00043     :max_opened_files(_max_opened_files),tot_miss(0),tot_access(0),mode(_mode)
00044 {}
00045 
00046 ofstream * MRUFileList::getFile(string fname)
00047 
00048 {
00049     tot_access++;
00050     list_typ::iterator it = mru_list.end();
00051     ofstream * ofile;
00052   
00053     // search for the wanted file in the MRU list
00054     for(list_typ::iterator it2 = mru_list.begin(); it2 != mru_list.end(); ++it2)
00055         if(it2->first == fname)
00056         {
00057             it=it2;
00058             break;
00059         }
00060 
00061     // the file is not currently opened. 
00062     if(it == mru_list.end())
00063     {
00064         tot_miss++;
00065         // If we have already the max of opened files, we close the least recently used
00066         if((signed)mru_list.size() >= max_opened_files)
00067         {
00068             (mru_list.back().second)->close();
00069             delete (mru_list.back().second);
00070             mru_list.pop_back();
00071         }
00072         ofile = new ofstream(fname.c_str(),mode);
00073         if(ofile->bad())
00074         {
00075             error="Could not open/create file "+fname+".";
00076             return NULL;
00077         }
00078         mru_list.push_front(make_pair(fname,ofile));
00079         return ofile;
00080     }
00081   
00082     // else, we move the file to the top of the list and return the associated ofstream ptr
00083   
00084     ofile=it->second;
00085     mru_list.erase(it);
00086     mru_list.push_front(make_pair(fname,ofile));
00087     return ofile;
00088 }
00089   
00090 MRUFileList::~MRUFileList()
00091 {
00092     for(list_typ::iterator it = mru_list.begin(); it != mru_list.end(); ++it)
00093     {
00094         (it->second)->close();
00095         delete it->second;
00096     }
00097 }
00098 
00099 } //end of namespace PLearn
00100 
00101 
00102 /*
00103   Local Variables:
00104   mode:c++
00105   c-basic-offset:4
00106   c-file-style:"stroustrup"
00107   c-file-offsets:((innamespace . 0)(inline-open . 0))
00108   indent-tabs-mode:nil
00109   fill-column:79
00110   End:
00111 */
00112 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=79 :
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