/*
* R : A Computer Language for Statistical Data Analysis
* Copyright (C) 1995, 1996 Robert Gentleman and Ross Ihaka
* Copyright (C) 1997--2008 The R Development Core Team
* Copyright (C) 2003, 2004 The R Foundation
* Copyright (C) 2010 bedatadriven
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*/
package org.renjin.primitives.subset;
import org.renjin.eval.EvalException;
import org.renjin.sexp.AtomicVector;
import org.renjin.sexp.IntVector;
/**
* Positive numbers are interpreted as positional subscripts,
* indicating which elements should be selected by index:
* x[1:5] selects the first five elements.
*/
public class PositionalSubscript extends Subscript {
private final int indices[];
private int count;
public PositionalSubscript(AtomicVector vector) {
indices = new int[vector.length()];
for(int i=0;i!=indices.length;++i) {
int index = vector.getElementAsInt(i);
if(index != 0) {
if(IntVector.isNA(index)
) {
indices[count++] = IntVector.NA;
} else {
indices[count++] = index-1;
}
}
}
}
static boolean arePositions(AtomicVector indices) {
boolean hasNeg = false;
boolean hasPos = false;
for(int i=0;i!=indices.length();++i) {
int index = indices.getElementAsInt(i);
if(index > 0 || IntVector.isNA(index)) {
hasPos = true;
} else if(index < 0) {
hasNeg = true;
}
}
if(hasNeg && hasPos) {
throw new EvalException("only 0's may be mixed with negative subscripts");
}
return !hasNeg;
}
@Override
public int getCount() {
return count;
}
@Override
public int getAt(int i) {
return indices[i];
}
}