/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 com.tom_roush.fontbox.cff;
import java.util.List;
/**
* A Handler for CharStringCommands.
*
* @author Villu Ruusmann
* @version $Revision$
*/
public abstract class CharStringHandler
{
/**
* Handler for a sequence of CharStringCommands.
*
* @param sequence of CharStringCommands
*
* @return may return a command sequence of a subroutine
*/
@SuppressWarnings(value = { "unchecked" })
public List<Integer> handleSequence(List<Object> sequence)
{
List<Integer> numbers = null;
int offset = 0;
int size = sequence.size();
for (int i = 0; i < size; i++)
{
Object object = sequence.get(i);
if (object instanceof CharStringCommand)
{
if (numbers == null)
numbers = (List) sequence.subList(offset, i);
else
numbers.addAll((List) sequence.subList(offset, i));
List<Integer> stack = handleCommand(numbers, (CharStringCommand) object);
if (stack != null && !stack.isEmpty())
numbers = stack;
else
numbers = null;
offset = i + 1;
}
}
if (numbers != null && !numbers.isEmpty())
return numbers;
else
return null;
}
/**
* Handler for CharStringCommands.
*
* @param numbers a list of numbers
* @param command the CharStringCommand
*
* @return may return a command sequence of a subroutine
*/
public abstract List<Integer> handleCommand(List<Integer> numbers, CharStringCommand command);
}