/*
* Redberry: symbolic tensor computations.
*
* Copyright (c) 2010-2013:
* Stanislav Poslavsky <stvlpos@mail.ru>
* Bolotin Dmitriy <bolotin.dmitriy@gmail.com>
*
* This file is part of Redberry.
*
* Redberry 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 3 of the License, or
* (at your option) any later version.
*
* Redberry 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 Redberry. If not, see <http://www.gnu.org/licenses/>.
*/
package cc.redberry.core.utils;
import cc.redberry.concurrent.OutputPortUnsafe;
import cc.redberry.core.indices.IndicesFactory;
import cc.redberry.core.tensor.SimpleTensor;
import cc.redberry.core.tensor.Tensor;
import cc.redberry.core.tensor.Tensors;
import gnu.trove.set.hash.TIntHashSet;
/**
* Sequentially generates variables of the form "prefix0","prefix1","prefix2","prefix3" etc., so that each
* symbol does not appear in the specified tensor.
*
* @author Dmitry Bolotin
* @author Stanislav Poslavsky
* @see TensorUtils#generateReplacementsOfScalars(cc.redberry.core.tensor.Tensor, cc.redberry.concurrent.OutputPortUnsafe)
*/
public class LocalSymbolsProvider implements OutputPortUnsafe<SimpleTensor> {
private final String prefix;
private final TIntHashSet forbiddenNames;
private long counter = 0;
/**
* Creates provider with given prefix.
*
* @param forbidden forbidden content
* @param prefix string prefix
*/
public LocalSymbolsProvider(Tensor forbidden, String prefix) {
this.forbiddenNames = TensorUtils.getSimpleTensorsNames(forbidden);
this.prefix = prefix;
}
@Override
public SimpleTensor take() {
SimpleTensor st;
do {
st = Tensors.simpleTensor(prefix + (counter++), IndicesFactory.EMPTY_SIMPLE_INDICES);
} while (forbiddenNames.contains(st.getName()));
return st;
}
}