MemoryBuilder.java

/*
 * Copyright (c) 2001-2017, Zoltan Farkas All Rights Reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 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 General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * Additionally licensed with:
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.spf4j.zel.vm;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import org.spf4j.base.Pair;


public final class MemoryBuilder {

    private final ArrayList<Object> memory;

    private final Map<String, Integer> symbolTable;

    private int idx = 0;

    public MemoryBuilder() {
        memory = new ArrayList<>();
        symbolTable = new HashMap<>();
    }

    MemoryBuilder(final ArrayList<Object> memory, final Map<String, Integer> symbolTable) {
        this.memory = memory;
        this.symbolTable = symbolTable;
        this.idx = memory.size();
    }

    public void addSymbol(final String symbol) {
        if (!symbolTable.containsKey(symbol)) {
            memory.add(null);
            symbolTable.put(symbol, idx++);
        } else {
          throw new IllegalArgumentException("Duplicate symbol definition: " + symbol);
        }
    }

    public void addSymbol(final String symbol, final Object value) {
        if (!symbolTable.containsKey(symbol)) {
            memory.add(value);
            symbolTable.put(symbol, idx++);
        } else {
            final int position = symbolTable.get(symbol);
            memory.ensureCapacity(position + 1);
            memory.set(position, value);
        }
    }


    public Pair<Object[], Map<String, Integer>> build() {
        return Pair.of(memory.toArray(), (Map<String, Integer>) new HashMap<>(symbolTable));
    }


    public MemoryBuilder copy() {
        return new MemoryBuilder(new ArrayList<>(memory), new HashMap<>(symbolTable));
    }

    @Override
    public String toString() {
        return "MemoryBuilder{" + "memory=" + memory + ", symbolTable=" + symbolTable + ", idx=" + idx + '}';
    }

}