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/* $Id: Memory.cpp 1649 2009-10-19 14:35:01Z terpstra $
*
* Memory.cpp - Memory segment for inserts prior to commit
*
* Copyright (C) 2002 - Wesley W. Terpstra
*
* License: GPL
*
* Authors: 'Wesley W. Terpstra' <wesley@terpstra.ca>
*
* This program 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; version 2.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#define _FILE_OFFSET_BITS 64
#include "io.h"
#include "Memory.h"
#include "Source.h"
#include "esort.h"
#include "File.h"
namespace ESort
{
class ForwardMemorySource : public Source
{
protected:
typedef std::multiset<std::string> Data;
Data::iterator i, e;
public:
ForwardMemorySource(Data::iterator i_, Data::iterator e_)
: i(i_), e(e_) { }
int advance();
};
int ForwardMemorySource::advance()
{
// Test for eof
if (i == e)
{
errno = 0;
return -1;
}
// Return the key
tail = reinterpret_cast<const unsigned char*>(i->c_str());
length = i->length();
dup = 0;
++i;
return 0;
}
class BackwardMemorySource : public Source
{
protected:
typedef std::multiset<std::string> Data;
Data::iterator i, b;
public:
BackwardMemorySource(Data::iterator i_, Data::iterator b_)
: i(i_), b(b_) { }
int advance();
};
int BackwardMemorySource::advance()
{
// Test for eof
if (i == b)
{
errno = 0;
return -1;
}
// move to the next position
--i;
// Return the key
tail = reinterpret_cast<const unsigned char*>(i->c_str());
length = i->length();
dup = 0;
return 0;
}
auto_ptr<Source> Memory::openMemory(const string& k, bool forward)
{
if (forward)
return auto_ptr<Source>(
new ForwardMemorySource(data.lower_bound(k), data.end()));
else return auto_ptr<Source>(
new BackwardMemorySource(data.lower_bound(k), data.begin()));
}
int Memory::category(const Parameters& p) const
{
long sum = 0;
for (Data::const_iterator i = data.begin(); i != data.end(); ++i)
sum += i->length();
return categorize((sum / p.blockSize()) + 1); //!!! +1 is evil
}
}
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