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/*
* ProGuard -- shrinking, optimization, obfuscation, and preverification
* of Java bytecode.
*
* Copyright (c) 2002-2013 Eric Lafortune (eric@graphics.cornell.edu)
*
* 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 2 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, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package proguard.classfile.util;
import proguard.classfile.ClassConstants;
/**
* An <code>InternalTypeEnumeration</code> provides an enumeration of all
* parameter types listed in a given internal method descriptor or signature.
* The signature can also be a class signature. The return type of a method
* descriptor can be retrieved separately.
*
* @author Eric Lafortune
*/
public class InternalTypeEnumeration
{
private String descriptor;
private int firstIndex;
private int lastIndex;
private int index;
/**
* Creates a new InternalTypeEnumeration for the given method descriptor.
*/
public InternalTypeEnumeration(String descriptor)
{
this.descriptor = descriptor;
this.firstIndex = descriptor.indexOf(ClassConstants.INTERNAL_METHOD_ARGUMENTS_OPEN);
this.lastIndex = descriptor.indexOf(ClassConstants.INTERNAL_METHOD_ARGUMENTS_CLOSE);
this.index = firstIndex + 1;
if (lastIndex < 0)
{
lastIndex = descriptor.length();
}
}
/**
* Returns the formal type parameters from the descriptor, assuming it's a
* method descriptor.
*/
public String formalTypeParameters()
{
return descriptor.substring(0, firstIndex);
}
/**
* Returns whether the enumeration can provide more types from the method
* descriptor.
*/
public boolean hasMoreTypes()
{
return index < lastIndex;
}
/**
* Returns the next type from the method descriptor.
*/
public String nextType()
{
int startIndex = index;
skipArray();
char c = descriptor.charAt(index++);
switch (c)
{
case ClassConstants.INTERNAL_TYPE_CLASS_START:
case ClassConstants.INTERNAL_TYPE_GENERIC_VARIABLE_START:
{
skipClass();
break;
}
case ClassConstants.INTERNAL_TYPE_GENERIC_START:
{
skipGeneric();
break;
}
}
return descriptor.substring(startIndex, index);
}
/**
* Returns the return type from the descriptor, assuming it's a method
* descriptor.
*/
public String returnType()
{
return descriptor.substring(lastIndex + 1);
}
// Small utility methods.
private void skipArray()
{
while (descriptor.charAt(index) == ClassConstants.INTERNAL_TYPE_ARRAY)
{
index++;
}
}
private void skipClass()
{
while (true)
{
char c = descriptor.charAt(index++);
switch (c)
{
case ClassConstants.INTERNAL_TYPE_GENERIC_START:
skipGeneric();
break;
case ClassConstants.INTERNAL_TYPE_CLASS_END:
return;
}
}
}
private void skipGeneric()
{
int nestingLevel = 1;
do
{
char c = descriptor.charAt(index++);
switch (c)
{
case ClassConstants.INTERNAL_TYPE_GENERIC_START:
nestingLevel++;
break;
case ClassConstants.INTERNAL_TYPE_GENERIC_END:
nestingLevel--;
break;
}
}
while (nestingLevel > 0);
}
/**
* A main method for testing the type enumeration.
*/
public static void main(String[] args)
{
try
{
for (int index = 0; index < args.length; index++)
{
String descriptor = args[index];
System.out.println("Descriptor ["+descriptor+"]");
InternalTypeEnumeration enumeration = new InternalTypeEnumeration(descriptor);
if (enumeration.firstIndex >= 0)
{
System.out.println(" Formal type parameters ["+enumeration.formalTypeParameters()+"]");
}
while (enumeration.hasMoreTypes())
{
System.out.println(" Type ["+enumeration.nextType()+"]");
}
if (enumeration.lastIndex < descriptor.length())
{
System.out.println(" Return type ["+enumeration.returnType()+"]");
}
}
}
catch (Exception ex)
{
ex.printStackTrace();
}
}
}
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