package org.aspectj.apache.bcel.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 apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    "Apache BCEL", nor may "Apache" appear in their name, without
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 *
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 * ====================================================================
 *
 * 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
 * <http://www.apache.org/>.
 */

import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import org.aspectj.apache.bcel.Constants;
import org.aspectj.apache.bcel.classfile.annotation.AnnotationGen;
import org.aspectj.apache.bcel.classfile.annotation.RuntimeAnnos;
import org.aspectj.apache.bcel.classfile.annotation.RuntimeInvisAnnos;
import org.aspectj.apache.bcel.classfile.annotation.RuntimeInvisParamAnnos;
import org.aspectj.apache.bcel.classfile.annotation.RuntimeParamAnnos;
import org.aspectj.apache.bcel.classfile.annotation.RuntimeVisAnnos;
import org.aspectj.apache.bcel.classfile.annotation.RuntimeVisParamAnnos;
import org.aspectj.apache.bcel.generic.Type;
import org.aspectj.apache.bcel.util.ByteSequence;

Utility functions that do not really belong to any class in particular.
Author:M. Dahm modified: Andy Clement 2-mar-05 Removed unnecessary static and optimized
Version:$Id: Utility.java,v 1.14 2009/09/28 16:39:46 aclement Exp $
/** * Utility functions that do not really belong to any class in particular. * * @version $Id: Utility.java,v 1.14 2009/09/28 16:39:46 aclement Exp $ * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A> * * modified: Andy Clement 2-mar-05 Removed unnecessary static and optimized */
public abstract class Utility { /* * 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. */ private static boolean wide = false;
Convert bit field of flags into string such as 'static final'.
Params:
  • access_flags – Access flags
Returns:String representation of flags
/** * 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'.
Params:
  • access_flags – Access flags
  • for_class – access flags are for class qualifiers ?
Returns:String representation of flags
/** * 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: see comment at top of class... if (for_class && ((p == Constants.ACC_SUPER) || (p == Constants.ACC_INTERFACE))) { continue; } buf.append(Constants.ACCESS_NAMES[i]).append(" "); } } return buf.toString().trim(); }
Returns:"class" or "interface", depending on the ACC_INTERFACE flag
/** * @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.
Params:
  • code – byte code array
  • constant_pool – Array of constants
  • index – offset in `code' array (number of opcodes, not bytes!)
  • length – number of opcodes to decompile, -1 for all
  • verbose – be verbose, e.g. print constant pool index
Returns:String representation of byte codes
/** * 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 <EM>(number of opcodes, not bytes!)</EM> * @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(); }
Disassemble a stream of byte codes and return the string representation.
/** * Disassemble a stream of byte codes and return the string representation. */
public static final String codeToString(byte[] code, ConstantPool constant_pool, int index, int length) { return codeToString(code, constant_pool, index, length, true); } 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.
Params:
  • str – The long class name
Returns:Compacted class name
/** * Shorten long class names, <em>java/lang/String</em> becomes <em>String</em>. * * @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 ..
Params:
  • str – The long class name
  • prefix – The prefix the get rid off
  • chopit – Flag that determines whether chopping is executed or not
Returns:Compacted class name
/** * Shorten long class name <em>str</em>, i.e., chop off the <em>prefix</em>, if the class name starts with this string and the * flag <em>chopit</em> is true. Slashes <em>/</em> are converted to dots <em>.</em>. * * @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) { str = str.replace('/', '.'); if (chopit) { int len = prefix.length(); // If string starts with 'prefix' and contains no further dots if (str.startsWith(prefix)) { String result = str.substring(len); if (result.indexOf('.') == -1) { str = result; } } } 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.
Params:
  • str – The long class name
  • chopit – Flag that determines whether chopping is executed or not
Returns:Compacted class name
/** * Shorten long class names, <em>java/lang/String</em> becomes <em>java.lang.String</em>, e.g.. If <em>chopit</em> is * <em>true</em> the prefix <em>java.lang</em> 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); } 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); }
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.
/** * 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. */
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) != ')') { ResultHolder rh = signatureToStringInternal(signature.substring(index), chopit); String param_type = rh.getResult(); 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 += rh.getConsumedChars(); } index++; // 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) { buf.setLength(buf.length() - 2); } buf.append(")"); return access + ((access.length() > 0) ? " " : "") + // May be an empty string type + " " + name + buf.toString(); }
Replace all occurences of old in str with new.
Params:
  • str – String to permute
  • old – String to be replaced
@paramnew Replacement string
Returns:new String object
/** * Replace all occurences of <em>old</em> in <em>str</em> with <em>new</em>. * * @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 { index = str.indexOf(old); if (index != -1) { old_index = 0; // 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) { System.err.println(e); } return str; }
Converts signature to string with all class names compacted.
Params:
  • signature – to convert
Returns:Human readable signature
/** * 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); } public static final String signatureToString(String signature, boolean chopit) { ResultHolder rh = signatureToStringInternal(signature, chopit); return rh.getResult(); }
This method converts this string into a Java type declaration such as 'String[]' and throws a `ClassFormatException' when the parsed type is invalid.
/** * This method converts this string into a Java type declaration such as 'String[]' and throws a `ClassFormatException' when the * parsed type is invalid. */
public static final ResultHolder signatureToStringInternal(String signature, boolean chopit) { int processedChars = 1; // This is the default, read just one char try { switch (signature.charAt(0)) { case 'B': return ResultHolder.BYTE; case 'C': return ResultHolder.CHAR; case 'D': return ResultHolder.DOUBLE; case 'F': return ResultHolder.FLOAT; case 'I': return ResultHolder.INT; case 'J': return ResultHolder.LONG; case 'L': { // Full class name int index = signature.indexOf(';'); // Look for closing ';' if (index < 0) { throw new ClassFormatException("Invalid signature: " + signature); } if (signature.length() > index + 1 && signature.charAt(index + 1) == '>') { index = index + 2; } int genericStart = signature.indexOf('<'); if (genericStart != -1) { int genericEnd = signature.indexOf('>'); // FIXME asc going to need a lot more work in here for generics ResultHolder rh = signatureToStringInternal(signature.substring(genericStart + 1, genericEnd), chopit); StringBuffer sb = new StringBuffer(); sb.append(signature.substring(1, genericStart)); sb.append("<").append(rh.getResult()).append(">"); ResultHolder retval = new ResultHolder(compactClassName(sb.toString(), chopit), genericEnd + 1); return retval; } else { processedChars = index + 1; // "Lblabla;" `L' and `;' are removed ResultHolder retval = new ResultHolder(compactClassName(signature.substring(1, index), chopit), processedChars); return retval; } } case 'S': return ResultHolder.SHORT; case 'Z': return ResultHolder.BOOLEAN; case '[': { // Array declaration StringBuffer brackets; int consumedChars, n; brackets = new StringBuffer(); // Accumulate []'s // Count opening brackets and look for optional size argument for (n = 0; signature.charAt(n) == '['; n++) { brackets.append("[]"); } consumedChars = n; ResultHolder restOfIt = signatureToStringInternal(signature.substring(n), chopit); consumedChars += restOfIt.getConsumedChars(); brackets.insert(0, restOfIt.getResult()); return new ResultHolder(brackets.toString(), consumedChars); } case 'V': return ResultHolder.VOID; default: throw new ClassFormatException("Invalid signature: `" + signature + "'"); } } catch (StringIndexOutOfBoundsException e) { // Should never occur throw new ClassFormatException("Invalid signature: " + e + ":" + signature); } }
Return type of method signature as a byte value as defined in Constants
Params:
  • signature – in format described above
See Also:
Returns:type of method signature
/** * Return type of method signature as a byte value as defined in <em>Constants</em> * * @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); } }
Convert (signed) byte to (unsigned) short value, i.e., all negative values become positive.
/** * 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
Returns:bytes as hexidecimal string, e.g. 00 FA 12 ...
/** * 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); // Just one digit, so prepend 0 if (b < 0x10) { 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.
Params:
  • i – integer to format
  • length – length of desired string
  • left_justify – format left or right
  • fill – fill character
Returns:formatted int
/** * 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.
Params:
  • str – string to format
  • length – length of desired string
  • left_justify – format left or right
  • fill – fill character
Returns:formatted string
/** * 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; } }
Escape all occurences of newline chars '\n', quotes \", etc.
/** * 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(); }
Converts a list of AnnotationGen objects into a set of attributes that can be attached to the class file.
Params:
  • cp – The constant pool gen where we can create the necessary name refs
  • annotations – A list of AnnotationGen objects
/** * Converts a list of AnnotationGen objects into a set of attributes that can be attached to the class file. * * @param cp The constant pool gen where we can create the necessary name refs * @param annotations A list of AnnotationGen objects */
public static Collection<RuntimeAnnos> getAnnotationAttributes(ConstantPool cp, List<AnnotationGen> annotations) { if (annotations.size() == 0) { return null; } try { int countVisible = 0; int countInvisible = 0; // put the annotations in the right output stream for (AnnotationGen a : annotations) { if (a.isRuntimeVisible()) { countVisible++; } else { countInvisible++; } } ByteArrayOutputStream rvaBytes = new ByteArrayOutputStream(); ByteArrayOutputStream riaBytes = new ByteArrayOutputStream(); DataOutputStream rvaDos = new DataOutputStream(rvaBytes); DataOutputStream riaDos = new DataOutputStream(riaBytes); rvaDos.writeShort(countVisible); riaDos.writeShort(countInvisible); // put the annotations in the right output stream for (AnnotationGen a : annotations) { if (a.isRuntimeVisible()) { a.dump(rvaDos); } else { a.dump(riaDos); } } rvaDos.close(); riaDos.close(); byte[] rvaData = rvaBytes.toByteArray(); byte[] riaData = riaBytes.toByteArray(); int rvaIndex = -1; int riaIndex = -1; if (rvaData.length > 2) { rvaIndex = cp.addUtf8("RuntimeVisibleAnnotations"); } if (riaData.length > 2) { riaIndex = cp.addUtf8("RuntimeInvisibleAnnotations"); } List<RuntimeAnnos> newAttributes = new ArrayList<RuntimeAnnos>(); if (rvaData.length > 2) { newAttributes.add(new RuntimeVisAnnos(rvaIndex, rvaData.length, rvaData, cp)); } if (riaData.length > 2) { newAttributes.add(new RuntimeInvisAnnos(riaIndex, riaData.length, riaData, cp)); } return newAttributes; } catch (IOException e) { System.err.println("IOException whilst processing annotations"); e.printStackTrace(); } return null; }
Annotations against a class are stored in one of four attribute kinds: - RuntimeVisibleParameterAnnotations - RuntimeInvisibleParameterAnnotations
/** * Annotations against a class are stored in one of four attribute kinds: - RuntimeVisibleParameterAnnotations - * RuntimeInvisibleParameterAnnotations */
// OPTIMIZE looks heavyweight? public static Attribute[] getParameterAnnotationAttributes(ConstantPool cp, List<AnnotationGen>[] vec) { int visCount[] = new int[vec.length]; int totalVisCount = 0; int invisCount[] = new int[vec.length]; int totalInvisCount = 0; try { for (int i = 0; i < vec.length; i++) { List<AnnotationGen> l = vec[i]; if (l != null) { for (AnnotationGen element : l) { if (element.isRuntimeVisible()) { visCount[i]++; totalVisCount++; } else { invisCount[i]++; totalInvisCount++; } } } } // Lets do the visible ones ByteArrayOutputStream rvaBytes = new ByteArrayOutputStream(); DataOutputStream rvaDos = new DataOutputStream(rvaBytes); rvaDos.writeByte(vec.length); // First goes number of parameters for (int i = 0; i < vec.length; i++) { rvaDos.writeShort(visCount[i]); if (visCount[i] > 0) { List<AnnotationGen> l = vec[i]; for (AnnotationGen element : l) { if (element.isRuntimeVisible()) { element.dump(rvaDos); } } } } rvaDos.close(); // Lets do the invisible ones ByteArrayOutputStream riaBytes = new ByteArrayOutputStream(); DataOutputStream riaDos = new DataOutputStream(riaBytes); riaDos.writeByte(vec.length); // First goes number of parameters for (int i = 0; i < vec.length; i++) { riaDos.writeShort(invisCount[i]); if (invisCount[i] > 0) { List<AnnotationGen> l = vec[i]; for (AnnotationGen element : l) { if (!element.isRuntimeVisible()) { element.dump(riaDos); } } } } riaDos.close(); byte[] rvaData = rvaBytes.toByteArray(); byte[] riaData = riaBytes.toByteArray(); int rvaIndex = -1; int riaIndex = -1; if (totalVisCount > 0) { rvaIndex = cp.addUtf8("RuntimeVisibleParameterAnnotations"); } if (totalInvisCount > 0) { riaIndex = cp.addUtf8("RuntimeInvisibleParameterAnnotations"); } List<RuntimeParamAnnos> newAttributes = new ArrayList<RuntimeParamAnnos>(); if (totalVisCount > 0) { newAttributes.add(new RuntimeVisParamAnnos(rvaIndex, rvaData.length, rvaData, cp)); } if (totalInvisCount > 0) { newAttributes.add(new RuntimeInvisParamAnnos(riaIndex, riaData.length, riaData, cp)); } return newAttributes.toArray(new Attribute[] {}); } catch (IOException e) { System.err.println("IOException whilst processing parameter annotations"); e.printStackTrace(); } return null; } public static class ResultHolder { private String result; private int consumed; public static final ResultHolder BYTE = new ResultHolder("byte", 1); public static final ResultHolder CHAR = new ResultHolder("char", 1); public static final ResultHolder DOUBLE = new ResultHolder("double", 1); public static final ResultHolder FLOAT = new ResultHolder("float", 1); public static final ResultHolder INT = new ResultHolder("int", 1); public static final ResultHolder LONG = new ResultHolder("long", 1); public static final ResultHolder SHORT = new ResultHolder("short", 1); public static final ResultHolder BOOLEAN = new ResultHolder("boolean", 1); public static final ResultHolder VOID = new ResultHolder("void", 1); public ResultHolder(String s, int c) { result = s; consumed = c; } public String getResult() { return result; } public int getConsumedChars() { return consumed; } }
Return type of signature as a byte value as defined in Constants
Params:
  • signature – in format described above
See Also:
Returns:type of signature
/** * Return type of signature as a byte value as defined in <em>Constants</em> * * @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); } } public static final byte typeOfSignature(char c) throws ClassFormatException { switch (c) { 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 type of signature: " + c); } }
Disassemble a stream of byte codes and return the string representation.
Params:
  • bytes – stream of bytes
  • constant_pool – Array of constants
  • verbose – be verbose, e.g. print constant pool index
Returns:String representation of byte code
/** * 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 = bytes.readByte(); if (b != 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) + ">" + (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) + (verbose ? " (" + index + ")" : "")); break; case Constants.INVOKEINTERFACE: index = bytes.readUnsignedShort(); int nargs = bytes.readUnsignedByte(); // historical, redundant buf.append("\t" + constant_pool.constantToString(index) + (verbose ? " (" + index + ")\t" : "") + nargs + "\t" + bytes.readUnsignedByte()); // Last byte is a reserved // space break; case Constants.INVOKEDYNAMIC://http://docs.oracle.com/javase/specs/jvms/se7/html/jvms-6.html#jvms-6.5.invokedynamic index = bytes.readUnsignedShort(); bytes.readUnsignedShort(); // zeroes buf.append("\t" + constant_pool.constantToString(index) + (verbose ? " (" + index + ")" : "")); 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) + (verbose ? " (" + index + ")" : "")); break; case Constants.LDC: index = bytes.readUnsignedByte(); buf.append("\t\t" + constant_pool.constantToString(index) + (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.iLen[opcode] - 1) > 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!"); System.exit(-1); } } } } return buf.toString(); } // private helpers private static final int pow2(int n) { return 1 << n; }
Convert type to Java method signature, e.g. int[] f(java.lang.String x) becomes (Ljava/lang/String;)[I
Params:
  • returnType – what the method returns
  • argTypes – what are the argument types
Returns:method signature for given type(s).
/** * Convert type to Java method signature, e.g. int[] f(java.lang.String x) becomes (Ljava/lang/String;)[I * * @param returnType what the method returns * @param argTypes what are the argument types * @return method signature for given type(s). */
public static String toMethodSignature(Type returnType, Type[] argTypes) { StringBuffer buf = new StringBuffer("("); int length = (argTypes == null) ? 0 : argTypes.length; for (int i = 0; i < length; i++) { buf.append(argTypes[i].getSignature()); } buf.append(')'); buf.append(returnType.getSignature()); return buf.toString(); } }