/*
* Bytecode Analysis Framework
* Copyright (C) 2004, University of Maryland
*
* 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package edu.umd.cs.findbugs.ba;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.NoSuchElementException;
import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.InvokeInstruction;
/**
* A simple class to parse method signatures.
*
* @author David Hovemeyer
*/
public class SignatureParser {
final int totalArgumentSize;
public int getTotalArgumentSize() {
return totalArgumentSize;
}
final int parameterOffset[];
public int getSlotsFromTopOfStackForParameter(int paramNum) {
int result = totalArgumentSize - parameterOffset[paramNum];
return result;
}
private class ParameterSignatureIterator implements Iterator<String> {
private int index = 1;
public boolean hasNext() {
return index < signature.length() && signature.charAt(index) != ')';
}
public String next() {
if (!hasNext())
throw new NoSuchElementException();
StringBuilder result = new StringBuilder();
boolean done;
do {
done = true;
int ch = signature.charAt(index);
switch (ch) {
case 'B':
case 'C':
case 'D':
case 'F':
case 'I':
case 'J':
case 'S':
case 'Z':
result.append(signature.charAt(index));
++index;
break;
case 'L':
int semi = signature.indexOf(';', index + 1);
if (semi < 0)
throw new IllegalStateException("Invalid method signature: " + signature);
result.append(signature.substring(index, semi + 1));
index = semi + 1;
break;
case '[':
result.append('[');
++index;
done = false;
break;
case 'V':
default:
throw new IllegalStateException("Invalid method signature: " + signature);
}
} while (!done);
return result.toString();
}
public void remove() {
throw new UnsupportedOperationException();
}
}
private final String signature;
@Override
public String toString() {
return signature;
}
/**
* Constructor.
*
* @param signature
* the method signature to be parsed
*/
public SignatureParser(String signature) {
if (!signature.startsWith("("))
throw new IllegalArgumentException("Bad method signature: " + signature);
this.signature = signature;
ArrayList<Integer> offsets = new ArrayList<Integer>();
Iterator<String> i = parameterSignatureIterator();
int totalSize = 0;
while (i.hasNext()) {
String s = i.next();
if (s.equals("D") || s.equals("J"))
totalSize += 2;
else
totalSize += 1;
offsets.add(totalSize);
}
totalArgumentSize = totalSize;
parameterOffset = new int[offsets.size()];
for (int j = 0; j < offsets.size(); j++)
parameterOffset[j] = offsets.get(j);
}
/**
* Get an Iterator over signatures of the method parameters.
*
* @return Iterator which returns the parameter type signatures in order
*/
public Iterator<String> parameterSignatureIterator() {
return new ParameterSignatureIterator();
}
/**
* Get the method return type signature.
*
* @return the method return type signature
*/
public String getReturnTypeSignature() {
int endOfParams = signature.lastIndexOf(')');
if (endOfParams < 0)
throw new IllegalArgumentException("Bad method signature: " + signature);
return signature.substring(endOfParams + 1);
}
/**
* Get the number of parameters in the signature.
*
* @return the number of parameters
*/
public int getNumParameters() {
int count = 0;
for (Iterator<String> i = parameterSignatureIterator(); i.hasNext();) {
i.next();
++count;
}
return count;
}
public boolean hasReferenceParameters() {
for (Iterator<String> i = parameterSignatureIterator(); i.hasNext();) {
char c = i.next().charAt(0);
if (c == 'L' || c == '[')
return true;
}
return false;
}
public String getParameter(int pos) {
int count = 0;
for (Iterator<String> i = parameterSignatureIterator(); i.hasNext();) {
String p = i.next();
if (pos == count)
return p;
++count;
}
throw new IndexOutOfBoundsException("Asked for parameter " + pos + " of " + signature);
}
/**
* Determine whether or not given signature denotes a reference type.
*
* @param signature
* a signature
* @return true if signature denotes a reference type, false otherwise
*/
public static boolean isReferenceType(String signature) {
return signature.startsWith("L") || signature.startsWith("[");
}
/**
* Get the number of parameters passed to method invocation.
*
* @param inv
* @param cpg
* @return int number of parameters
*/
public static int getNumParametersForInvocation(InvokeInstruction inv, ConstantPoolGen cpg) {
SignatureParser sigParser = new SignatureParser(inv.getSignature(cpg));
return sigParser.getNumParameters();
}
/**
* Return how many stack frame slots a type whose signature is given will
* occupy. long and double values take 2 slots, while all other kinds of
* values take 1 slot.
*
* @param sig
* a type signature
* @return number of stack frame slots a value of the given type will occupy
*/
public static int getNumSlotsForType(String sig) {
if (sig.equals("J") || sig.equals("D")) {
return 2;
} else {
return 1;
}
}
public static void main(String[] args) {
if (args.length != 1) {
System.err.println("Usage: " + SignatureParser.class.getName() + " '<method signature>'");
System.exit(1);
}
SignatureParser parser = new SignatureParser(args[0]);
for (Iterator<String> i = parser.parameterSignatureIterator(); i.hasNext();) {
System.out.println(i.next());
}
System.out.println(parser.getNumParameters() + " parameter(s)");
}
}
// vim:ts=4