/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package org.apache.tomcat.util.bcel.classfile;
import java.io.IOException;
import org.apache.tomcat.util.bcel.Constants;
import org.apache.tomcat.util.bcel.util.ByteSequence;
/**
* Utility functions that do not really belong to any class in particular.
*
* @version $Id: Utility.java 895187 2010-01-02 13:17:11Z rjung $
* @author <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
*/
public abstract class Utility {
private static int unwrap( ThreadLocal tl ) {
return ((Integer) tl.get()).intValue();
}
private static void wrap( ThreadLocal tl, int value ) {
tl.set(new Integer(value));
}
private static ThreadLocal consumed_chars = new ThreadLocal() {
protected Object initialValue() {
return new Integer(0);
}
};/* 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]).append(" ");
}
}
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
* <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++) {
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).append(codeToString(stream, constant_pool, verbose))
.append('\n');
}
}
} catch (IOException e) {
System.out.println(buf.toString());
e.printStackTrace();
throw new ClassFormatException("Byte code error: " + e, e);
}
return buf.toString();
}
/**
* 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 = ").append(default_offset).append(", low = ").append(low)
.append(", high = ").append(high).append("(");
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 = ").append(default_offset).append(", npairs = ").append(
npairs).append(" (");
for (int i = 0; i < npairs; i++) {
match[i] = bytes.readInt();
jump_table[i] = offset + bytes.readInt();
buf.append("(").append(match[i]).append(", ").append(jump_table[i]).append(")");
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#").append((bytes.getIndex() - 1) + bytes.readShort());
break;
/* 32-bit wide jumps
*/
case Constants.GOTO_W:
case Constants.JSR_W:
buf.append("\t\t#").append(((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%").append(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<").append(Constants.TYPE_NAMES[bytes.readByte()]).append(">");
break;
/* Access object/class fields.
*/
case Constants.GETFIELD:
case Constants.GETSTATIC:
case Constants.PUTFIELD:
case Constants.PUTSTATIC:
index = bytes.readUnsignedShort();
buf.append("\t\t").append(
constant_pool.constantToString(index, Constants.CONSTANT_Fieldref)).append(
(verbose ? " (" + index + ")" : ""));
break;
/* Operands are references to classes in constant pool
*/
case Constants.NEW:
case Constants.CHECKCAST:
buf.append("\t");
/* FALL THRU */
case Constants.INSTANCEOF:
index = bytes.readUnsignedShort();
buf.append("\t<").append(
constant_pool.constantToString(index, Constants.CONSTANT_Class))
.append(">").append((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").append(
constant_pool.constantToString(index, Constants.CONSTANT_Methodref))
.append((verbose ? " (" + index + ")" : ""));
break;
case Constants.INVOKEINTERFACE:
index = bytes.readUnsignedShort();
int nargs = bytes.readUnsignedByte(); // historical, redundant
buf.append("\t").append(
constant_pool
.constantToString(index, Constants.CONSTANT_InterfaceMethodref))
.append(verbose ? " (" + index + ")\t" : "").append(nargs).append("\t")
.append(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").append(
constant_pool.constantToString(index, constant_pool.getConstant(index)
.getTag())).append((verbose ? " (" + index + ")" : ""));
break;
case Constants.LDC:
index = bytes.readUnsignedByte();
buf.append("\t\t").append(
constant_pool.constantToString(index, constant_pool.getConstant(index)
.getTag())).append((verbose ? " (" + index + ")" : ""));
break;
/* Array of references.
*/
case Constants.ANEWARRAY:
index = bytes.readUnsignedShort();
buf.append("\t\t<").append(
compactClassName(constant_pool.getConstantString(index,
Constants.CONSTANT_Class), false)).append(">").append(
(verbose ? " (" + index + ")" : ""));
break;
/* Multidimensional array of references.
*/
case Constants.MULTIANEWARRAY: {
index = bytes.readUnsignedShort();
int dimensions = bytes.readUnsignedByte();
buf.append("\t<").append(
compactClassName(constant_pool.getConstantString(index,
Constants.CONSTANT_Class), false)).append(">\t").append(dimensions)
.append((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%").append(vindex).append("\t").append(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!");
System.exit(-1);
}
}
}
}
return buf.toString();
}
/**
* 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 <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 ) {
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, <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);
}
/**
* A returntype signature represents the return value from a method.
* It is a series of bytes in the following grammar:
*
* <return_signature> ::= <field_type> | 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:
*
* <argument_signature> ::= <field_type>
*
* A method signature represents the arguments that the method expects, and
* the value that it returns.
* <method_signature> ::= (<arguments_signature>) <return_signature>
* <arguments_signature>::= <argument_signature>*
*
* 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(" ").append(l.getName());
}
} else {
buf.append(" arg").append(var_index);
}
if ("double".equals(param_type) || "long".equals(param_type)) {
var_index += 2;
} else {
var_index++;
}
buf.append(", ");
//corrected concurrent private static field acess
index += unwrap(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, e);
}
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();
}
// Guess what this does
private static final int pow2( int n ) {
return 1 << n;
}
/**
* Replace all occurrences 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;
try {
if ((index = str.indexOf(old)) != -1) { // `old' found in str
StringBuffer buf = new StringBuffer();
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:
*
* <PRE>
* <field_signature> ::= <field_type>
* <field_type> ::= <base_type>|<object_type>|<array_type>
* <base_type> ::= B|C|D|F|I|J|S|Z
* <object_type> ::= L<fullclassname>;
* <array_type> ::= [<field_type>
*
* 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<fullclassname>; ... an object of the given class
* S short signed short
* Z boolean true or false
* [<field sig> ... array
* </PRE>
*
* 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 ) {
//corrected concurrent private static field acess
wrap(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);
}
//corrected concurrent private static field acess
wrap(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 brackets;
String type;
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 `<field_type>'
type = signatureToString(signature.substring(n), chopit);
//corrected concurrent private static field acess
//Utility.consumed_chars += consumed_chars; is replaced by:
int _temp = unwrap(Utility.consumed_chars) + consumed_chars;
wrap(Utility.consumed_chars, _temp);
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: " + signature, e);
}
}
/**
* 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) {
buf.append('0');
}
buf.append(hex);
if (i < bytes.length - 1) {
buf.append(' ');
}
}
return buf.toString();
}
/**
* 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);
}
return new String(buf) + str;
}
// A-Z, g-z, _, $
private static final int FREE_CHARS = 48;
static int[] CHAR_MAP = new int[FREE_CHARS];
static int[] MAP_CHAR = new int[256]; // Reverse map
static {
int j = 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;
}
/**
* 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();
}
}