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/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * 
 * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
 * 
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License. You can obtain
 * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
 * or glassfish/bootstrap/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 * 
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
 * Sun designates this particular file as subject to the "Classpath" exception
 * as provided by Sun in the GPL Version 2 section of the License file that
 * accompanied this code.  If applicable, add the following below the License
 * Header, with the fields enclosed by brackets [] replaced by your own
 * identifying information: "Portions Copyrighted [year]
 * [name of copyright owner]"
 * 
 * Contributor(s):
 * 
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 */

package com.sun.org.apache.bcel.internal.classfile;

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache BCEL" must not be used to endorse or promote products
 *    derived from this software without prior written permission. For
 *    written permission, please contact [email protected].
 *
 * 5. Products derived from this software may not be called "Apache",
 *    "Apache BCEL", nor may "Apache" appear in their name, without
 *    prior written permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * .
 */

import com.sun.org.apache.bcel.internal.Constants;
import com.sun.org.apache.bcel.internal.util.ByteSequence;
import java.io.*;
import java.util.ArrayList;
import java.util.zip.*;

/**
 * Utility functions that do not really belong to any class in particular.
 *
 * @version $Id: Utility.java,v 1.3 2007-07-19 04:34:43 ofung Exp $
 * @author  M. Dahm
 */
public abstract class Utility {
  private static int consumed_chars; /* How many chars have been consumed
				      * during parsing in signatureToString().
				      * Read by methodSignatureToString().
				      * Set by side effect,but only internally.
				      */
  private static boolean wide=false; /* The `WIDE' instruction is used in the
				      * byte code to allow 16-bit wide indices
				      * for local variables. This opcode
				      * precedes an `ILOAD', e.g.. The opcode
				      * immediately following takes an extra
				      * byte which is combined with the
				      * following byte to form a
				      * 16-bit value.
				      */
  /**
   * Convert bit field of flags into string such as `static final'.
   *
   * @param  access_flags Access flags
   * @return String representation of flags
   */
  public static final String accessToString(int access_flags) {
    return accessToString(access_flags, false);
  }

  /**
   * Convert bit field of flags into string such as `static final'.
   *
   * Special case: Classes compiled with new compilers and with the
   * `ACC_SUPER' flag would be said to be "synchronized". This is
   * because SUN used the same value for the flags `ACC_SUPER' and
   * `ACC_SYNCHRONIZED'. 
   *
   * @param  access_flags Access flags
   * @param  for_class access flags are for class qualifiers ?
   * @return String representation of flags
   */
  public static final String accessToString(int access_flags, 
					    boolean for_class)
  {
    StringBuffer buf = new StringBuffer();

    int p = 0;
    for(int i=0; p < Constants.MAX_ACC_FLAG; i++) { // Loop through known flags
      p = pow2(i);

      if((access_flags & p) != 0) {
	/* Special case: Classes compiled with new compilers and with the
	 * `ACC_SUPER' flag would be said to be "synchronized". This is
	 * because SUN used the same value for the flags `ACC_SUPER' and
	 * `ACC_SYNCHRONIZED'.
	 */
	if(for_class && ((p == Constants.ACC_SUPER) || (p == Constants.ACC_INTERFACE)))
	  continue;	    

	buf.append(Constants.ACCESS_NAMES[i] + " ");
      }
    }

    return buf.toString().trim();
  }

  /**
   * @return "class" or "interface", depending on the ACC_INTERFACE flag
   */
  public static final String classOrInterface(int access_flags) {
    return ((access_flags & Constants.ACC_INTERFACE) != 0)? "interface" : "class";
  }

  /**
   * Disassemble a byte array of JVM byte codes starting from code line 
   * `index' and return the disassembled string representation. Decode only
   * `num' opcodes (including their operands), use -1 if you want to
   * decompile everything.
   *
   * @param  code byte code array
   * @param  constant_pool Array of constants
   * @param  index offset in `code' array
   * (number of opcodes, not bytes!)
   * @param  length number of opcodes to decompile, -1 for all
   * @param  verbose be verbose, e.g. print constant pool index
   * @return String representation of byte codes
   */
  public static final String codeToString(byte[] code, 
					  ConstantPool constant_pool, 
					  int index, int length, boolean verbose)
  {
    StringBuffer buf    = new StringBuffer(code.length * 20); // Should be sufficient
    ByteSequence stream = new ByteSequence(code);

    try {
      for(int i=0; i < index; i++) // Skip `index' lines of code
	codeToString(stream, constant_pool, verbose);

      for(int i=0; stream.available() > 0; i++) {
	if((length < 0) || (i < length)) {
	  String indices = fillup(stream.getIndex() + ":", 6, true, ' ');
	  buf.append(indices + codeToString(stream, constant_pool, verbose) + '\n');
	}
      }
    } catch(IOException e) {
      System.out.println(buf.toString());
      e.printStackTrace();
      throw new ClassFormatException("Byte code error: " + e);
    }

    return buf.toString();
  }

  public static final String codeToString(byte[] code, 
					  ConstantPool constant_pool, 
					  int index, int length) {
    return codeToString(code, constant_pool, index, length, true);
  }

  /**
   * Disassemble a stream of byte codes and return the
   * string representation.
   *
   * @param  bytes stream of bytes
   * @param  constant_pool Array of constants
   * @param  verbose be verbose, e.g. print constant pool index
   * @return String representation of byte code
   */
  public static final String codeToString(ByteSequence bytes,
					  ConstantPool constant_pool, boolean verbose)
       throws IOException
  {
    short        opcode = (short)bytes.readUnsignedByte();
    int          default_offset=0, low, high, npairs;
    int          index, vindex, constant;
    int[]        match, jump_table;
    int          no_pad_bytes=0, offset;
    StringBuffer buf = new StringBuffer(Constants.OPCODE_NAMES[opcode]);

    /* Special case: Skip (0-3) padding bytes, i.e., the
     * following bytes are 4-byte-aligned
     */
    if((opcode == Constants.TABLESWITCH) || (opcode == Constants.LOOKUPSWITCH)) {
      int remainder = bytes.getIndex() % 4;
      no_pad_bytes  = (remainder == 0)? 0 : 4 - remainder;

      for(int i=0; i < no_pad_bytes; i++) {
	byte b;

	if((b=bytes.readByte()) != 0)
	  System.err.println("Warning: Padding byte != 0 in " +
			     Constants.OPCODE_NAMES[opcode] + ":" + b);
      }

      // Both cases have a field default_offset in common
      default_offset = bytes.readInt();
    }

    switch(opcode) {
      /* Table switch has variable length arguments.
       */
    case Constants.TABLESWITCH:
      low  = bytes.readInt();
      high = bytes.readInt();

      offset = bytes.getIndex() - 12 - no_pad_bytes - 1;
      default_offset += offset;

      buf.append("\tdefault = " + default_offset + ", low = " + low + 
		 ", high = " + high + "(");

      jump_table = new int[high - low + 1];
      for(int i=0; i < jump_table.length; i++) {
	jump_table[i] = offset + bytes.readInt();
	buf.append(jump_table[i]);

	if(i < jump_table.length - 1)
	  buf.append(", ");
      }
      buf.append(")");

      break;

      /* Lookup switch has variable length arguments.
       */
    case Constants.LOOKUPSWITCH: {

      npairs = bytes.readInt();
      offset = bytes.getIndex() - 8 - no_pad_bytes - 1;
	  
      match      = new int[npairs];
      jump_table = new int[npairs];
      default_offset += offset;

      buf.append("\tdefault = " + default_offset + ", npairs = " + npairs +
		 " (");

      for(int i=0; i < npairs; i++) {
	match[i]      = bytes.readInt();

	jump_table[i] = offset + bytes.readInt();

	buf.append("(" + match[i] + ", " + jump_table[i] + ")");

	if(i < npairs - 1)
	  buf.append(", ");
      }
      buf.append(")");
    }
    break;

    /* Two address bytes + offset from start of byte stream form the
     * jump target
     */
    case Constants.GOTO:      case Constants.IFEQ:      case Constants.IFGE:      case Constants.IFGT:
    case Constants.IFLE:      case Constants.IFLT:      case Constants.JSR: case Constants.IFNE:
    case Constants.IFNONNULL: case Constants.IFNULL:    case Constants.IF_ACMPEQ:
    case Constants.IF_ACMPNE: case Constants.IF_ICMPEQ: case Constants.IF_ICMPGE: case Constants.IF_ICMPGT:
    case Constants.IF_ICMPLE: case Constants.IF_ICMPLT: case Constants.IF_ICMPNE:
      buf.append("\t\t#" + ((bytes.getIndex() - 1) + bytes.readShort()));
      break;
	  
      /* 32-bit wide jumps
       */
    case Constants.GOTO_W: case Constants.JSR_W:
      buf.append("\t\t#" + ((bytes.getIndex() - 1) + bytes.readInt()));
      break;

      /* Index byte references local variable (register)
       */
    case Constants.ALOAD:  case Constants.ASTORE: case Constants.DLOAD:  case Constants.DSTORE: case Constants.FLOAD:
    case Constants.FSTORE: case Constants.ILOAD:  case Constants.ISTORE: case Constants.LLOAD:  case Constants.LSTORE:
    case Constants.RET: 
      if(wide) {
	vindex = bytes.readUnsignedShort();
	wide=false; // Clear flag
      }
      else
	vindex = bytes.readUnsignedByte();

      buf.append("\t\t%" + vindex);
      break;

      /*
       * Remember wide byte which is used to form a 16-bit address in the
       * following instruction. Relies on that the method is called again with
       * the following opcode.
       */
    case Constants.WIDE:
      wide      = true;
      buf.append("\t(wide)");
      break;

      /* Array of basic type.
       */
    case Constants.NEWARRAY:
      buf.append("\t\t<" + Constants.TYPE_NAMES[bytes.readByte()] + ">");
      break;

      /* Access object/class fields.
       */
    case Constants.GETFIELD: case Constants.GETSTATIC: case Constants.PUTFIELD: case Constants.PUTSTATIC:
      index = bytes.readUnsignedShort();
      buf.append("\t\t" +
		 constant_pool.constantToString(index, Constants.CONSTANT_Fieldref) +
		 (verbose? " (" + index + ")" : ""));
      break;
	  
      /* Operands are references to classes in constant pool
       */
    case Constants.NEW:
    case Constants.CHECKCAST:
      buf.append("\t");
    case Constants.INSTANCEOF:
      index = bytes.readUnsignedShort();
      buf.append("\t<" + constant_pool.constantToString(index,
							Constants.CONSTANT_Class) +
		 ">" + (verbose? " (" + index + ")" : ""));
      break;

      /* Operands are references to methods in constant pool
       */
    case Constants.INVOKESPECIAL: case Constants.INVOKESTATIC: case Constants.INVOKEVIRTUAL:
      index = bytes.readUnsignedShort();
      buf.append("\t" + constant_pool.constantToString(index,
						       Constants.CONSTANT_Methodref) +
		 (verbose? " (" + index + ")" : ""));
      break;

    case Constants.INVOKEINTERFACE:
      index = bytes.readUnsignedShort();
      int nargs = bytes.readUnsignedByte(); // historical, redundant
      buf.append("\t" + 
		 constant_pool.constantToString(index,
						Constants.CONSTANT_InterfaceMethodref) +
		 (verbose? " (" + index + ")\t" : "") + nargs + "\t" + 
		 bytes.readUnsignedByte()); // Last byte is a reserved space
      break;
	
      /* Operands are references to items in constant pool
       */
    case Constants.LDC_W: case Constants.LDC2_W:
      index = bytes.readUnsignedShort();

      buf.append("\t\t" + constant_pool.constantToString
		 (index, constant_pool.getConstant(index).getTag()) +
		 (verbose? " (" + index + ")" : ""));
      break;

    case Constants.LDC:
      index = bytes.readUnsignedByte();

      buf.append("\t\t" + 
		 constant_pool.constantToString
		 (index, constant_pool.getConstant(index).getTag()) +
		 (verbose? " (" + index + ")" : ""));
      break;
	
      /* Array of references.
       */
    case Constants.ANEWARRAY:
      index = bytes.readUnsignedShort();
	  
      buf.append("\t\t<" + compactClassName(constant_pool.getConstantString
					  (index, Constants.CONSTANT_Class), false) +
		 ">" + (verbose? " (" + index + ")": ""));
      break;
	
      /* Multidimensional array of references.
       */
    case Constants.MULTIANEWARRAY: {
      index          = bytes.readUnsignedShort();
      int dimensions = bytes.readUnsignedByte();

      buf.append("\t<" + compactClassName(constant_pool.getConstantString
					  (index, Constants.CONSTANT_Class), false) +
		 ">\t" + dimensions + (verbose? " (" + index + ")" : ""));
    }
    break;

    /* Increment local variable.
     */
    case Constants.IINC:
      if(wide) {
	vindex   = bytes.readUnsignedShort();
	constant = bytes.readShort();
	wide     = false;
      }
      else {
	vindex   = bytes.readUnsignedByte();
	constant = bytes.readByte();
      }
      buf.append("\t\t%" + vindex + "\t" + constant);
      break;

    default:
      if(Constants.NO_OF_OPERANDS[opcode] > 0) {
	for(int i=0; i < Constants.TYPE_OF_OPERANDS[opcode].length; i++) {
	  buf.append("\t\t");
	  switch(Constants.TYPE_OF_OPERANDS[opcode][i]) {
	  case Constants.T_BYTE:  buf.append(bytes.readByte()); break;
	  case Constants.T_SHORT: buf.append(bytes.readShort());       break;
	  case Constants.T_INT:   buf.append(bytes.readInt());         break;
					      
	  default: // Never reached
	    System.err.println("Unreachable default case reached!");
	    buf.setLength(0);
	  }
	}
      }
    }

    return buf.toString();
  }

  public static final String codeToString(ByteSequence bytes, ConstantPool constant_pool)
    throws IOException
  {
    return codeToString(bytes, constant_pool, true);
  }

  /**
   * Shorten long class names, java/lang/String becomes 
   * String.
   *
   * @param str The long class name
   * @return Compacted class name
   */
  public static final String compactClassName(String str) {
    return compactClassName(str, true);
  }
 
  /**
   * Shorten long class name str, i.e., chop off the prefix,
   * if the
   * class name starts with this string and the flag chopit is true.
   * Slashes / are converted to dots ..
   *
   * @param str The long class name
   * @param prefix The prefix the get rid off
   * @param chopit Flag that determines whether chopping is executed or not
   * @return Compacted class name
   */
  public static final String compactClassName(String str, 
					      String prefix,
					      boolean chopit)
  {
    int len = prefix.length();

    str = str.replace('/', '.'); // Is `/' on all systems, even DOS

    if(chopit) {
      // If string starts with `prefix' and contains no further dots
      if(str.startsWith(prefix) &&
	 (str.substring(len).indexOf('.') == -1))
	str = str.substring(len);
    }
	
    return str;
  }

  /**
   * Shorten long class names, java/lang/String becomes 
   * java.lang.String,
   * e.g.. If chopit is true the prefix java.lang
   * is also removed.
   *
   * @param str The long class name
   * @param chopit Flag that determines whether chopping is executed or not
   * @return Compacted class name
   */
  public static final String compactClassName(String str, boolean chopit) {
    return compactClassName(str, "java.lang.", chopit);
  }    

  private static final boolean is_digit(char ch) {
    return (ch >= '0') && (ch <= '9');
  }    
  
  private static final boolean is_space(char ch) {
    return (ch == ' ') || (ch == '\t') || (ch == '\r') || (ch == '\n');
  }    

  /**
   * @return `flag' with bit `i' set to 1
   */
  public static final int setBit(int flag, int i) {
    return flag | pow2(i); 
  }

  /**
   * @return `flag' with bit `i' set to 0
   */
  public static final int clearBit(int flag, int i) {
    int bit = pow2(i); 
    return (flag & bit) == 0? flag : flag ^ bit; 
  }
   
  /**
   * @return true, if bit `i' in `flag' is set
   */
  public static final boolean isSet(int flag, int i) {
    return (flag & pow2(i)) != 0;
  }

  /**
   * Converts string containing the method return and argument types 
   * to a byte code method signature.
   *
   * @param  ret Return type of method
   * @param  argv Types of method arguments
   * @return Byte code representation of method signature
   */
  public final static String methodTypeToSignature(String ret, String[] argv)
    throws ClassFormatException
  {
    StringBuffer buf = new StringBuffer("(");
    String       str;

    if(argv != null)
      for(int i=0; i < argv.length; i++) {
	str = getSignature(argv[i]);

	if(str.endsWith("V")) // void can't be a method argument
	  throw new ClassFormatException("Invalid type: " + argv[i]);

	buf.append(str);
      }

    str = getSignature(ret);

    buf.append(")" + str);

    return buf.toString();
  }

  /**
   * @param  signature    Method signature
   * @return Array of argument types
   * @throws  ClassFormatException  
   */
  public static final String[] methodSignatureArgumentTypes(String signature)
    throws ClassFormatException 
  {
    return methodSignatureArgumentTypes(signature, true);
  }    

  /**
   * @param  signature    Method signature
   * @param chopit Shorten class names ?
   * @return Array of argument types
   * @throws  ClassFormatException  
   */
  public static final String[] methodSignatureArgumentTypes(String signature,
							    boolean chopit)
    throws ClassFormatException
  {
    ArrayList vec = new ArrayList();
    int       index;
    String[]  types;

    try { // Read all declarations between for `(' and `)'
      if(signature.charAt(0) != '(')
	throw new ClassFormatException("Invalid method signature: " + signature);

      index = 1; // current string position

      while(signature.charAt(index) != ')') {
	vec.add(signatureToString(signature.substring(index), chopit));
	index += consumed_chars; // update position
      }
    } catch(StringIndexOutOfBoundsException e) { // Should never occur
      throw new ClassFormatException("Invalid method signature: " + signature);
    }
	
    types = new String[vec.size()];
    vec.toArray(types);
    return types;
  }      
  /**
   * @param  signature    Method signature
   * @return return type of method
   * @throws  ClassFormatException  
   */
  public static final String methodSignatureReturnType(String signature)
       throws ClassFormatException 
  {
    return methodSignatureReturnType(signature, true);
  }    
  /**
   * @param  signature    Method signature
   * @param chopit Shorten class names ?
   * @return return type of method
   * @throws  ClassFormatException  
   */
  public static final String methodSignatureReturnType(String signature,
						       boolean chopit)
       throws ClassFormatException
  {
    int    index;
    String type;

    try {
      // Read return type after `)'
      index = signature.lastIndexOf(')') + 1; 
      type = signatureToString(signature.substring(index), chopit);
    } catch(StringIndexOutOfBoundsException e) { // Should never occur
      throw new ClassFormatException("Invalid method signature: " + signature);
    }

    return type;
  }

  /**
   * Converts method signature to string with all class names compacted.
   *
   * @param signature to convert
   * @param name of method
   * @param access flags of method
   * @return Human readable signature
   */
  public static final String methodSignatureToString(String signature,
						     String name,
						     String access) {
    return methodSignatureToString(signature, name, access, true);
  }

  public static final String methodSignatureToString(String signature,
						     String name,
						     String access,
						     boolean chopit) {
    return methodSignatureToString(signature, name, access, chopit, null);
  }

  /**
   * A return type signature represents the return value from a method.
   * It is a series of bytes in the following grammar:
   *
   *  ::=  | V
   *
   * The character V indicates that the method returns no value. Otherwise, the
   * signature indicates the type of the return value.
   * An argument signature represents an argument passed to a method:
   *
   *  ::= 
   *
   * A method signature represents the arguments that the method expects, and
   * the value that it returns.
   *  ::= () 
   * ::= *
   *
   * This method converts such a string into a Java type declaration like
   * `void _main(String[])' and throws a `ClassFormatException' when the parsed 
   * type is invalid.
   *
   * @param  signature    Method signature
   * @param  name         Method name
   * @param  access       Method access rights
   * @return Java type declaration
   * @throws  ClassFormatException  
   */
  public static final String methodSignatureToString(String signature,
						     String name,
						     String access,
						     boolean chopit,
						     LocalVariableTable vars)
    throws ClassFormatException
  {
    StringBuffer buf = new StringBuffer("(");
    String       type;
    int          index;
    int          var_index = (access.indexOf("static") >= 0)? 0 : 1;

    try { // Read all declarations between for `(' and `)'
      if(signature.charAt(0) != '(')
	throw new ClassFormatException("Invalid method signature: " + signature);

      index = 1; // current string position

      while(signature.charAt(index) != ')') {
	String param_type = signatureToString(signature.substring(index), chopit);
	buf.append(param_type);

	if(vars != null) {
	  LocalVariable l = vars.getLocalVariable(var_index);

	  if(l != null)
	    buf.append(" " + l.getName());
	} else
	  buf.append(" arg" + var_index);

	if("double".equals(param_type) || "long".equals(param_type))
	  var_index += 2;
	else
	  var_index++;

	buf.append(", ");
	index += consumed_chars; // update position
      }

      index++; // update position

      // Read return type after `)'
      type = signatureToString(signature.substring(index), chopit);

    } catch(StringIndexOutOfBoundsException e) { // Should never occur
      throw new ClassFormatException("Invalid method signature: " + signature);
    }

    if(buf.length() > 1) // Tack off the extra ", "
      buf.setLength(buf.length() - 2);

    buf.append(")");

    return access + ((access.length() > 0)? " " : "") + // May be an empty string
      type + " " + name + buf.toString();
  }

  // Guess what this does
  private static final int pow2(int n) {
    return 1 << n;
  }
    
  /**
   * Replace all occurences of old in str with new.
   *
   * @param str String to permute
   * @param old String to be replaced
   * @param new Replacement string
   * @return new String object
   */
  public static final String replace(String str, String old, String new_) {
    int          index, old_index;
    StringBuffer buf = new StringBuffer();

    try {
      if((index = str.indexOf(old)) != -1) { // `old' found in str
	old_index = 0;                       // String start offset
	  
	// While we have something to replace
	while((index = str.indexOf(old, old_index)) != -1) {
	  buf.append(str.substring(old_index, index)); // append prefix
	  buf.append(new_);                            // append replacement
	      
	  old_index = index + old.length(); // Skip `old'.length chars
	}

	buf.append(str.substring(old_index)); // append rest of string
	str = buf.toString();	
      }
    } catch(StringIndexOutOfBoundsException e) { // Should not occur
      System.err.println(e);
    }

    return str;
  }

  /**
   * Converts signature to string with all class names compacted.
   *
   * @param signature to convert
   * @return Human readable signature
   */
  public static final String signatureToString(String signature) {
    return signatureToString(signature, true);
  }    

  /**
   * The field signature represents the value of an argument to a function or 
   * the value of a variable. It is a series of bytes generated by the 
   * following grammar:
   *
   * 
   *  ::= 
   *       ::= ||
   *        ::= B|C|D|F|I|J|S|Z
   *      ::= L;
   *       ::= [
   *
   * The meaning of the base types is as follows:
   * B byte signed byte
   * C char character
   * D double double precision IEEE float
   * F float single precision IEEE float
   * I int integer
   * J long long integer
   * L; ... an object of the given class
   * S short signed short
   * Z boolean true or false
   * [ ... array
   * 
* * This method converts this string into a Java type declaration such as * `String[]' and throws a `ClassFormatException' when the parsed type is * invalid. * * @param signature Class signature * @param chopit Flag that determines whether chopping is executed or not * @return Java type declaration * @throws ClassFormatException */ public static final String signatureToString(String signature, boolean chopit) { consumed_chars = 1; // This is the default, read just one char like `B' try { switch(signature.charAt(0)) { case 'B' : return "byte"; case 'C' : return "char"; case 'D' : return "double"; case 'F' : return "float"; case 'I' : return "int"; case 'J' : return "long"; case 'L' : { // Full class name int index = signature.indexOf(';'); // Look for closing `;' if(index < 0) throw new ClassFormatException("Invalid signature: " + signature); consumed_chars = index + 1; // "Lblabla;" `L' and `;' are removed return compactClassName(signature.substring(1, index), chopit); } case 'S' : return "short"; case 'Z' : return "boolean"; case '[' : { // Array declaration int n; StringBuffer buf, brackets; String type; char ch; int consumed_chars; // Shadows global var brackets = new StringBuffer(); // Accumulate []'s // Count opening brackets and look for optional size argument for(n=0; signature.charAt(n) == '['; n++) brackets.append("[]"); consumed_chars = n; // Remember value // The rest of the string denotes a `' type = signatureToString(signature.substring(n), chopit); Utility.consumed_chars += consumed_chars; return type + brackets.toString(); } case 'V' : return "void"; default : throw new ClassFormatException("Invalid signature: `" + signature + "'"); } } catch(StringIndexOutOfBoundsException e) { // Should never occur throw new ClassFormatException("Invalid signature: " + e + ":" + signature); } } /** Parse Java type such as "char", or "java.lang.String[]" and return the * signature in byte code format, e.g. "C" or "[Ljava/lang/String;" respectively. * * @param type Java type * @return byte code signature */ public static String getSignature(String type) { StringBuffer buf = new StringBuffer(); char[] chars = type.toCharArray(); boolean char_found = false, delim = false; int index = -1; loop: for(int i=0; i < chars.length; i++) { switch(chars[i]) { case ' ': case '\t': case '\n': case '\r': case '\f': if(char_found) delim = true; break; case '[': if(!char_found) throw new RuntimeException("Illegal type: " + type); index = i; break loop; default: char_found = true; if(!delim) buf.append(chars[i]); } } int brackets = 0; if(index > 0) brackets = countBrackets(type.substring(index)); type = buf.toString(); buf.setLength(0); for(int i=0; i < brackets; i++) buf.append('['); boolean found = false; for(int i=Constants.T_BOOLEAN; (i <= Constants.T_VOID) && !found; i++) { if(Constants.TYPE_NAMES[i].equals(type)) { found = true; buf.append(Constants.SHORT_TYPE_NAMES[i]); } } if(!found) // Class name buf.append('L' + type.replace('.', '/') + ';'); return buf.toString(); } private static int countBrackets(String brackets) { char[] chars = brackets.toCharArray(); int count = 0; boolean open = false; for(int i=0; iConstants * * @param signature in format described above * @return type of method signature * @see Constants */ public static final byte typeOfMethodSignature(String signature) throws ClassFormatException { int index; try { if(signature.charAt(0) != '(') throw new ClassFormatException("Invalid method signature: " + signature); index = signature.lastIndexOf(')') + 1; return typeOfSignature(signature.substring(index)); } catch(StringIndexOutOfBoundsException e) { throw new ClassFormatException("Invalid method signature: " + signature); } } /** * Return type of signature as a byte value as defined in Constants * * @param signature in format described above * @return type of signature * @see Constants */ public static final byte typeOfSignature(String signature) throws ClassFormatException { try { switch(signature.charAt(0)) { case 'B' : return Constants.T_BYTE; case 'C' : return Constants.T_CHAR; case 'D' : return Constants.T_DOUBLE; case 'F' : return Constants.T_FLOAT; case 'I' : return Constants.T_INT; case 'J' : return Constants.T_LONG; case 'L' : return Constants.T_REFERENCE; case '[' : return Constants.T_ARRAY; case 'V' : return Constants.T_VOID; case 'Z' : return Constants.T_BOOLEAN; case 'S' : return Constants.T_SHORT; default: throw new ClassFormatException("Invalid method signature: " + signature); } } catch(StringIndexOutOfBoundsException e) { throw new ClassFormatException("Invalid method signature: " + signature); } } /** Map opcode names to opcode numbers. E.g., return Constants.ALOAD for "aload" */ public static short searchOpcode(String name) { name = name.toLowerCase(); for(short i=0; i < Constants.OPCODE_NAMES.length; i++) if(Constants.OPCODE_NAMES[i].equals(name)) return i; return -1; } /** * Convert (signed) byte to (unsigned) short value, i.e., all negative * values become positive. */ private static final short byteToShort(byte b) { return (b < 0)? (short)(256 + b) : (short)b; } /** Convert bytes into hexidecimal string * * @return bytes as hexidecimal string, e.g. 00 FA 12 ... */ public static final String toHexString(byte[] bytes) { StringBuffer buf = new StringBuffer(); for(int i=0; i < bytes.length; i++) { short b = byteToShort(bytes[i]); String hex = Integer.toString(b, 0x10); if(b < 0x10) // just one digit, prepend '0' buf.append('0'); buf.append(hex); if(i < bytes.length - 1) buf.append(' '); } return buf.toString(); } /** * Return a string for an integer justified left or right and filled up with * `fill' characters if necessary. * * @param i integer to format * @param length length of desired string * @param left_justify format left or right * @param fill fill character * @return formatted int */ public static final String format(int i, int length, boolean left_justify, char fill) { return fillup(Integer.toString(i), length, left_justify, fill); } /** * Fillup char with up to length characters with char `fill' and justify it left or right. * * @param str string to format * @param length length of desired string * @param left_justify format left or right * @param fill fill character * @return formatted string */ public static final String fillup(String str, int length, boolean left_justify, char fill) { int len = length - str.length(); char[] buf = new char[(len < 0)? 0 : len]; for(int j=0; j < buf.length; j++) buf[j] = fill; if(left_justify) return str + new String(buf); else return new String(buf) + str; } static final boolean equals(byte[] a, byte[] b) { int size; if((size=a.length) != b.length) return false; for(int i=0; i < size; i++) if(a[i] != b[i]) return false; return true; } public static final void printArray(PrintStream out, Object[] obj) { out.println(printArray(obj, true)); } public static final void printArray(PrintWriter out, Object[] obj) { out.println(printArray(obj, true)); } public static final String printArray(Object[] obj) { return printArray(obj, true); } public static final String printArray(Object[] obj, boolean braces) { return printArray(obj, braces, false); } public static final String printArray(Object[] obj, boolean braces, boolean quote) { if(obj == null) return null; StringBuffer buf = new StringBuffer(); if(braces) buf.append('{'); for(int i=0; i < obj.length; i++) { if(obj[i] != null) { buf.append((quote? "\"" : "") + obj[i].toString() + (quote? "\"" : "")); } else { buf.append("null"); } if(i < obj.length - 1) { buf.append(", "); } } if(braces) buf.append('}'); return buf.toString(); } /** @return true, if character is one of (a, ... z, A, ... Z, 0, ... 9, _) */ public static boolean isJavaIdentifierPart(char ch) { return ((ch >= 'a') && (ch <= 'z')) || ((ch >= 'A') && (ch <= 'Z')) || ((ch >= '0') && (ch <= '9')) || (ch == '_'); } /** Encode byte array it into Java identifier string, i.e., a string * that only contains the following characters: (a, ... z, A, ... Z, * 0, ... 9, _, $). The encoding algorithm itself is not too * clever: if the current byte's ASCII value already is a valid Java * identifier part, leave it as it is. Otherwise it writes the * escape character($) followed by

  • the ASCII value as a * hexadecimal string, if the value is not in the range * 200..247
  • a Java identifier char not used in a lowercase * hexadecimal string, if the value is in the range * 200..247
    • * *

      This operation inflates the original byte array by roughly 40-50%

      * * @param bytes the byte array to convert * @param compress use gzip to minimize string */ public static String encode(byte[] bytes, boolean compress) throws IOException { if(compress) { ByteArrayOutputStream baos = new ByteArrayOutputStream(); GZIPOutputStream gos = new GZIPOutputStream(baos); gos.write(bytes, 0, bytes.length); gos.close(); baos.close(); bytes = baos.toByteArray(); } CharArrayWriter caw = new CharArrayWriter(); JavaWriter jw = new JavaWriter(caw); for(int i=0; i < bytes.length; i++) { int in = bytes[i] & 0x000000ff; // Normalize to unsigned jw.write(in); } return caw.toString(); } /** Decode a string back to a byte array. * * @param bytes the byte array to convert * @param uncompress use gzip to uncompress the stream of bytes */ public static byte[] decode(String s, boolean uncompress) throws IOException { char[] chars = s.toCharArray(); CharArrayReader car = new CharArrayReader(chars); JavaReader jr = new JavaReader(car); ByteArrayOutputStream bos = new ByteArrayOutputStream(); int ch; while((ch = jr.read()) >= 0) { bos.write(ch); } bos.close(); car.close(); jr.close(); byte[] bytes = bos.toByteArray(); if(uncompress) { GZIPInputStream gis = new GZIPInputStream(new ByteArrayInputStream(bytes)); byte[] tmp = new byte[bytes.length * 3]; // Rough estimate int count = 0; int b; while((b = gis.read()) >= 0) tmp[count++] = (byte)b; bytes = new byte[count]; System.arraycopy(tmp, 0, bytes, 0, count); } return bytes; } // A-Z, g-z, _, $ private static final int FREE_CHARS = 48; private static int[] CHAR_MAP = new int[FREE_CHARS]; private static int[] MAP_CHAR = new int[256]; // Reverse map private static final char ESCAPE_CHAR = '$'; static { int j = 0, k = 0; for(int i='A'; i <= 'Z'; i++) { CHAR_MAP[j] = i; MAP_CHAR[i] = j; j++; } for(int i='g'; i <= 'z'; i++) { CHAR_MAP[j] = i; MAP_CHAR[i] = j; j++; } CHAR_MAP[j] = '$'; MAP_CHAR['$'] = j; j++; CHAR_MAP[j] = '_'; MAP_CHAR['_'] = j; } /** Decode characters into bytes. * Used by decode() */ private static class JavaReader extends FilterReader { public JavaReader(Reader in) { super(in); } public int read() throws IOException { int b = in.read(); if(b != ESCAPE_CHAR) { return b; } else { int i = in.read(); if(i < 0) return -1; if(((i >= '0') && (i <= '9')) || ((i >= 'a') && (i <= 'f'))) { // Normal escape int j = in.read(); if(j < 0) return -1; char[] tmp = { (char)i, (char)j }; int s = Integer.parseInt(new String(tmp), 16); return s; } else { // Special escape return MAP_CHAR[i]; } } } public int read(char[] cbuf, int off, int len) throws IOException { for(int i=0; i < len; i++) cbuf[off + i] = (char)read(); return len; } } /** Encode bytes into valid java identifier characters. * Used by encode() */ private static class JavaWriter extends FilterWriter { public JavaWriter(Writer out) { super(out); } public void write(int b) throws IOException { if(isJavaIdentifierPart((char)b) && (b != ESCAPE_CHAR)) { out.write(b); } else { out.write(ESCAPE_CHAR); // Escape character // Special escape if(b >= 0 && b < FREE_CHARS) { out.write(CHAR_MAP[b]); } else { // Normal escape char[] tmp = Integer.toHexString(b).toCharArray(); if(tmp.length == 1) { out.write('0'); out.write(tmp[0]); } else { out.write(tmp[0]); out.write(tmp[1]); } } } } public void write(char[] cbuf, int off, int len) throws IOException { for(int i=0; i < len; i++) write(cbuf[off + i]); } public void write(String str, int off, int len) throws IOException { write(str.toCharArray(), off, len); } } /** * Escape all occurences of newline chars '\n', quotes \", etc. */ public static final String convertString(String label) { char[] ch = label.toCharArray(); StringBuffer buf = new StringBuffer(); for(int i=0; i < ch.length; i++) { switch(ch[i]) { case '\n': buf.append("\\n"); break; case '\r': buf.append("\\r"); break; case '\"': buf.append("\\\""); break; case '\'': buf.append("\\'"); break; case '\\': buf.append("\\\\"); break; default: buf.append(ch[i]); break; } } return buf.toString(); } }




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