gcc/libjava/gnu/java/rmi/server/RMIHashes.java

/*
  Copyright (c) 1996, 1997, 1998, 1999 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath 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, or (at your option)
any later version.
 
GNU Classpath 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.

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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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permission to link this library with independent modules to produce an
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package gnu.java.rmi.server;

import java.lang.reflect.Method;
import java.lang.Class;
import gnu.java.io.NullOutputStream;
import gnu.java.lang.reflect.TypeSignature;
import java.security.MessageDigest;
import java.security.DigestOutputStream;
import java.io.DataOutputStream;
import java.io.ByteArrayOutputStream;

public class RMIHashes
{
  //There're other places using DigestOutputStream to generate hash in classpath, but I think the way I used
  //here is more efficient, anyway, you can switch to DigestOutputStream by doing like "//or:" comments say.
  
  //or:add this statement: private static final NullOutputStream nullOutputStream = new NullOutputStream ();
  public static long getMethodHash(Method meth)
  {
    //Object Serialization Spec 8.3
    try
    {
        MessageDigest md = MessageDigest.getInstance ("SHA");
        //or:remove this statement: DigestOutputStream digest_out = new DigestOutputStream (nullOutputStream, md);
        ByteArrayOutputStream digest_out = new ByteArrayOutputStream();
        DataOutputStream data_out = new DataOutputStream (digest_out);
        
        StringBuffer sbuf = new StringBuffer();
        sbuf.append(meth.getName());
        sbuf.append('(');
        Class params[] = meth.getParameterTypes();
        for(int i = 0; i < params.length; i++)
            sbuf.append(TypeSignature.getEncodingOfClass(params[i]));
        sbuf.append(')');
        Class rcls = meth.getReturnType();
        if(rcls != Void.TYPE)
            sbuf.append(TypeSignature.getEncodingOfClass(rcls));
        else
            sbuf.append('V');
        
        data_out.writeUTF (sbuf.toString());
        data_out.flush();
        data_out.close ();

        md.update(digest_out.toByteArray()); //or:remove this statement
        byte[] sha = md.digest ();
        long result = 0;
        int len = sha.length < 8 ? sha.length : 8;
        for (int i=0; i < len; i++)
            result += (long)(sha[i] & 0xFF) << (8 * i);
        return result;
    }catch(Exception _){
        return -1L;
        }
  }

  public static long getInterfaceHash(Class clazz)
  {
    return clazz.hashCode ();
  }
}