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/* This file is part of kdev-pg-qt
Copyright (C) 2005 Roberto Raggi <roberto@kdevelop.org>
Copyright (C) 2006 Jakob Petsovits <jpetso@gmx.at>
Copyright (C) 2010 Jonathan Schmidt-Dominé <devel@the-user.org>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
#include "kdev-pg-first.h"
#include <cassert>
namespace KDevPG
{
void initializeFirst()
{
globalSystem.first(globalSystem.zero()).insert(globalSystem.zero());
for(auto i = globalSystem.terminals.begin();
i != globalSystem.terminals.end();
++i)
{
globalSystem.first(*i).insert(*i);
}
}
NextFirst::NextFirst(bool &changed): mChanged(changed)
{
}
void NextFirst::operator ()(Model::Node *node)
{
assert(nodeCast<Model::EvolveItem*>(node));
mMergeZeroBlocked = false;
visitNode(node);
}
bool NextFirst::blockZeroMerge(bool block)
{
bool old = mMergeZeroBlocked;
mMergeZeroBlocked = block;
return old;
}
void NextFirst::merge(Model::Node *__dest, Model::Node *__source, int K)
{
if(__source == 0 || __dest == 0)
return;
World::NodeSet &dest = globalSystem.first(__dest, K);
World::NodeSet &source = globalSystem.first(__source, K);
for (World::NodeSet::iterator it = source.begin(); it != source.end(); ++it)
{
if (mMergeZeroBlocked && nodeCast<Model::ZeroItem*>(*it))
{
continue;
}
if( !dest.contains(*it) )
{
dest.insert(*it);
mChanged = true;
}
}
}
void NextFirst::visitNode(Model::Node *node)
{
if(node == 0)
return;
if(mVisited.contains(node))
return;
mVisited.insert(node);
DefaultVisitor::visitNode(node);
mVisited.remove(node);
}
void NextFirst::visitAlternative(Model::AlternativeItem *node)
{
DefaultVisitor::visitAlternative(node);
merge(node, node->mLeft);
merge(node, node->mRight);
}
void NextFirst::visitCons(Model::ConsItem *node)
{
visitNode(node->mRight);
bool zero_blocked = mMergeZeroBlocked;
if (!reducesToEpsilon(node->mRight))
zero_blocked = blockZeroMerge(true);
visitNode(node->mLeft);
merge(node, node->mLeft);
if (reducesToEpsilon(node->mLeft))
{
visitNode(node->mRight);
merge(node, node->mRight);
}
blockZeroMerge(zero_blocked);
}
void computeFirst() // the closure of the FIRST sets
{
initializeFirst();
bool changed = true;
NextFirst next(changed);
while (changed)
{
changed = false;
for(QList<Model::EvolveItem*>::iterator it = globalSystem.rules.begin(); it != globalSystem.rules.end(); ++it)
{
next(*it);
}
}
}
}
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