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/**************************************************************************
* *
* Regina - A Normal Surface Theory Calculator *
* Computational Engine *
* *
* Copyright (c) 1999-2008, Ben Burton *
* For further details contact Ben Burton (bab@debian.org). *
* *
* 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; either version 2 of the *
* License, or (at your option) any later version. *
* *
* 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., 51 Franklin St, Fifth Floor, Boston, *
* MA 02110-1301, USA. *
* *
**************************************************************************/
/* end stub */
#include "algebra/nxmlalgebrareader.h"
#include "utilities/stringutils.h"
namespace regina {
/**
* A unique namespace containing various task-specific packet readers.
*/
namespace {
/**
* Reads a single relation in a group presentation.
*/
class NExpressionReader : public NXMLElementReader {
private:
NGroupExpression* exp;
long nGens;
public:
NExpressionReader(long newNGens) : exp(new NGroupExpression()),
nGens(newNGens) {
}
NGroupExpression* getExpression() {
return exp;
}
virtual void initialChars(const std::string& chars) {
std::list<std::string> tokens;
basicTokenise(back_inserter(tokens), chars);
std::string genStr, powStr;
long gen, pow;
std::string::size_type split;
for (std::list<std::string>::const_iterator it = tokens.begin();
it != tokens.end(); it++) {
split = (*it).find('^');
if (split == (*it).length()) {
delete exp;
exp = 0;
break;
}
genStr = (*it).substr(0, split);
powStr = (*it).substr(split + 1,
(*it).length() - split - 1);
if ((! valueOf(genStr, gen)) || (! valueOf(powStr, pow))) {
delete exp;
exp = 0;
break;
}
if (gen < 0 || gen >= nGens) {
delete exp;
exp = 0;
break;
}
exp->addTermLast(gen, pow);
}
}
};
}
void NXMLAbelianGroupReader::startElement(const std::string&,
const regina::xml::XMLPropertyDict& tagProps, NXMLElementReader*) {
long rank;
if (valueOf(tagProps.lookup("rank"), rank))
if (rank >= 0) {
group = new NAbelianGroup();
if (rank)
group->addRank(rank);
}
}
void NXMLAbelianGroupReader::initialChars(const std::string& chars) {
if (group) {
std::list<std::string> tokens;
if (basicTokenise(back_inserter(tokens), chars) > 0) {
std::multiset<NLargeInteger> torsion;
NLargeInteger val;
for (std::list<std::string>::const_iterator it = tokens.begin();
it != tokens.end(); it++)
if (valueOf(*it, val))
torsion.insert(val);
if (! torsion.empty())
group->addTorsionElements(torsion);
}
}
}
void NXMLGroupPresentationReader::startElement(const std::string&,
const regina::xml::XMLPropertyDict& tagProps, NXMLElementReader*) {
long nGen;
if (valueOf(tagProps.lookup("generators"), nGen))
if (nGen >= 0) {
group = new NGroupPresentation();
if (nGen)
group->addGenerator(nGen);
}
}
NXMLElementReader* NXMLGroupPresentationReader::startSubElement(
const std::string& subTagName,
const regina::xml::XMLPropertyDict& /* subTagProps */) {
if (group)
if (subTagName == "reln")
return new NExpressionReader(group->getNumberOfGenerators());
return new NXMLElementReader();
}
void NXMLGroupPresentationReader::endSubElement(const std::string& subTagName,
NXMLElementReader* subReader) {
if (group)
if (subTagName == "reln") {
NGroupExpression* exp =
dynamic_cast<NExpressionReader*>(subReader)->getExpression();
if (exp)
group->addRelation(exp);
}
}
} // namespace regina
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