/*
* Redberry: symbolic tensor computations.
*
* Copyright (c) 2010-2012:
* 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.parser;
import cc.redberry.core.context.Context;
import cc.redberry.core.indices.IndicesFactory;
import cc.redberry.core.indices.SimpleIndices;
import cc.redberry.core.utils.IntArrayList;
/**
*
* @author Dmitry Bolotin
* @author Stanislav Poslavsky
*/
public class ParserIndices {
public static SimpleIndices parseSimple(String expression) {
return IndicesFactory.createSimple(null, parse(expression));
}
public static int[] parse(String expression) {
IntArrayList indicesList = new IntArrayList();
boolean indexMode = false;
int indexState = 0;
int level = 0;
StringBuilder indicesString = null;
for (char c : expression.toCharArray()) {
if (c == '{') {
level++;
continue;
}
if (c == '}') {
level--;
continue;
}
if (c == '^') {
assert level == 0;
if (indexMode)
parseIndices(indicesList, indicesString, indexState);
indexMode = true;
indexState = 1;
indicesString = new StringBuilder();
continue;
}
if (c == '_' && level == 0) {
if (indexMode)
parseIndices(indicesList, indicesString, indexState);
indexMode = true;
indexState = 0;
indicesString = new StringBuilder();
continue;
}
indicesString.append(c);
}
if (level != 0)
throw new BracketsError();
if (indexMode)
parseIndices(indicesList, indicesString, indexState);
return indicesList.toArray();
}
/**
*
* Parse string representation and put result indices in indices
*
* @throws BracketsError if brackets are inconsistent (e.g. (a+(b)))) )
*
* @param indices integer array list of parsed indices
* @param indicesString string representation of indices
* @param state index state (upper or lower)
*/
static void parseIndices(IntArrayList indices, StringBuilder indicesString, int state) {
char c;
boolean toBuffer = false;
StringBuilder indexBuffer = new StringBuilder();
for (int i = 0; i < indicesString.length(); ++i) {
c = indicesString.charAt(i);
if (c == '{' || c == '}')
continue;
if (c == '_') {
indexBuffer.append(c);
toBuffer = true;
continue;
}
if (c == '\\') {
if (indexBuffer.length() != 0) {
indices.add(Context.get().getIndexConverterManager().getCode(indexBuffer.toString()) | state << 31);
indexBuffer = new StringBuilder();
}
indexBuffer.append(c);
toBuffer = true;
continue;
}
if (c == ' ') {
if (indexBuffer.length() != 0) {
indices.add(Context.get().getIndexConverterManager().getCode(indexBuffer.toString()) | state << 31);
indexBuffer = new StringBuilder();
}
continue;
}
if (toBuffer || (i < indicesString.length() - 1 && indicesString.charAt(i + 1) == '_')) {
indexBuffer.append(c);
continue;
}
indices.add(Context.get().getIndexConverterManager().getCode(String.valueOf(c)) | state << 31);
}
if (indexBuffer.length() != 0)
indices.add(Context.get().getIndexConverterManager().getCode(indexBuffer.toString()) | state << 31);
}
}