SignatureUpdater.java

/*******************************************************************************
 * Copyright (c) 2015 Jeff Martin.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the GNU Lesser General Public
 * License v3.0 which accompanies this distribution, and is available at
 * http://www.gnu.org/licenses/lgpl.html
 *
 * Contributors:
 * Jeff Martin - initial API and implementation
 ******************************************************************************/
package cuchaz.enigma.mapping;

import java.io.IOException;
import java.io.StringReader;
import java.util.List;

import com.google.common.collect.Lists;

public class SignatureUpdater
{
	
	public interface ClassNameUpdater
	{
		String update(String className);
	}
	
	public static String update(String signature, ClassNameUpdater updater)
	{
		try
		{
			StringBuilder buf = new StringBuilder();
			
			// read the signature character-by-character
			StringReader reader = new StringReader(signature);
			int i = -1;
			while((i = reader.read()) != -1)
			{
				char c = (char)i;
				
				// does this character start a class name?
				if(c == 'L')
				{
					// update the class name and add it to the buffer
					buf.append('L');
					String className = readClass(reader);
					if(className == null)
						throw new IllegalArgumentException(
							"Malformed signature: " + signature);
					buf.append(updater.update(className));
					buf.append(';');
				}else
					// copy the character into the buffer
					buf.append(c);
			}
			
			return buf.toString();
		}catch(IOException ex)
		{
			// I'm pretty sure a StringReader will never throw one of these
			throw new Error(ex);
		}
	}
	
	private static String readClass(StringReader reader) throws IOException
	{
		// read all the characters in the buffer until we hit a ';'
		// remember to treat generics correctly
		StringBuilder buf = new StringBuilder();
		int depth = 0;
		int i = -1;
		while((i = reader.read()) != -1)
		{
			char c = (char)i;
			
			if(c == '<')
				depth++;
			else if(c == '>')
				depth--;
			else if(depth == 0)
				if(c == ';')
					return buf.toString();
				else
					buf.append(c);
		}
		
		return null;
	}
	
	public static List<String> getClasses(String signature)
	{
		final List<String> classNames = Lists.newArrayList();
		update(signature, new ClassNameUpdater()
		{
			@Override
			public String update(String className)
			{
				classNames.add(className);
				return className;
			}
		});
		return classNames;
	}
}