/**
* Disassemble a stream of byte codes and return the string representation.
*
* @param stream data input stream
* @return String representation of byte code
*/
private final String codeToHTML(ByteSequence bytes, int method_number) throws IOException {
short opcode = (short) bytes.readUnsignedByte();
StringBuilder buf;
String name, signature;
int default_offset = 0, low, high;
int index, class_index, vindex, constant;
int[] jump_table;
int no_pad_bytes = 0, offset;
buf = new StringBuilder(256);
buf.append("<TT>").append(OPCODE_NAMES[opcode]).append("</TT></TD><TD>");
/* Special case: Skip (0-3) padding bytes, i.e., the
* following bytes are 4-byte-aligned
*/
if ((opcode == TABLESWITCH) || (opcode == LOOKUPSWITCH)) {
int remainder = bytes.getIndex() % 4;
no_pad_bytes = (remainder == 0) ? 0 : 4 - remainder;
for (int i = 0; i < no_pad_bytes; i++) {
bytes.readByte();
}
// Both cases have a field default_offset in common
default_offset = bytes.readInt();
}
switch (opcode) {
case TABLESWITCH:
low = bytes.readInt();
high = bytes.readInt();
offset = bytes.getIndex() - 12 - no_pad_bytes - 1;
default_offset += offset;
buf.append("<TABLE BORDER=1><TR>");
// Print switch indices in first row (and default)
jump_table = new int[high - low + 1];
for (int i = 0; i < jump_table.length; i++) {
jump_table[i] = offset + bytes.readInt();
buf.append("<TH>").append(low + i).append("</TH>");
}
buf.append("<TH>default</TH></TR>\n<TR>");
// Print target and default indices in second row
for (int i = 0; i < jump_table.length; i++) {
buf.append("<TD><A HREF=\"#code")
.append(method_number)
.append("@")
.append(jump_table[i])
.append("\">")
.append(jump_table[i])
.append("</A></TD>");
}
buf.append("<TD><A HREF=\"#code")
.append(method_number)
.append("@")
.append(default_offset)
.append("\">")
.append(default_offset)
.append("</A></TD></TR>\n</TABLE>\n");
break;
/* Lookup switch has variable length arguments.
*/
case LOOKUPSWITCH:
int npairs = bytes.readInt();
offset = bytes.getIndex() - 8 - no_pad_bytes - 1;
jump_table = new int[npairs];
default_offset += offset;
buf.append("<TABLE BORDER=1><TR>");
// Print switch indices in first row (and default)
for (int i = 0; i < npairs; i++) {
int match = bytes.readInt();
jump_table[i] = offset + bytes.readInt();
buf.append("<TH>").append(match).append("</TH>");
}
buf.append("<TH>default</TH></TR>\n<TR>");
// Print target and default indices in second row
for (int i = 0; i < npairs; i++) {
buf.append("<TD><A HREF=\"#code")
.append(method_number)
.append("@")
.append(jump_table[i])
.append("\">")
.append(jump_table[i])
.append("</A></TD>");
}
buf.append("<TD><A HREF=\"#code")
.append(method_number)
.append("@")
.append(default_offset)
.append("\">")
.append(default_offset)
.append("</A></TD></TR>\n</TABLE>\n");
break;
/* Two address bytes + offset from start of byte stream form the
* jump target.
*/
case GOTO:
case IFEQ:
case IFGE:
case IFGT:
case IFLE:
case IFLT:
case IFNE:
case IFNONNULL:
case IFNULL:
case IF_ACMPEQ:
case IF_ACMPNE:
case IF_ICMPEQ:
case IF_ICMPGE:
case IF_ICMPGT:
case IF_ICMPLE:
case IF_ICMPLT:
case IF_ICMPNE:
case JSR:
index = (int) (bytes.getIndex() + bytes.readShort() - 1);
buf.append("<A HREF=\"#code")
.append(method_number)
.append("@")
.append(index)
.append("\">")
.append(index)
.append("</A>");
break;
/* Same for 32-bit wide jumps
*/
case GOTO_W:
case JSR_W:
int windex = bytes.getIndex() + bytes.readInt() - 1;
buf.append("<A HREF=\"#code")
.append(method_number)
.append("@")
.append(windex)
.append("\">")
.append(windex)
.append("</A>");
break;
/* Index byte references local variable (register)
*/
case ALOAD:
case ASTORE:
case DLOAD:
case DSTORE:
case FLOAD:
case FSTORE:
case ILOAD:
case ISTORE:
case LLOAD:
case LSTORE:
case RET:
if (wide) {
vindex = bytes.readShort();
wide = false; // Clear flag
} else {
vindex = bytes.readUnsignedByte();
}
buf.append("%").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 WIDE:
wide = true;
buf.append("(wide)");
break;
/* Array of basic type.
*/
case NEWARRAY:
buf.append("<FONT COLOR=\"#00FF00\">")
.append(TYPE_NAMES[bytes.readByte()])
.append("</FONT>");
break;
/* Access object/class fields.
*/
case GETFIELD:
case GETSTATIC:
case PUTFIELD:
case PUTSTATIC:
index = bytes.readShort();
ConstantFieldref c1 =
(ConstantFieldref) constant_pool.getConstant(index, CONSTANT_Fieldref);
class_index = c1.getClassIndex();
name = constant_pool.getConstantString(class_index, CONSTANT_Class);
name = Utility.compactClassName(name, false);
index = c1.getNameAndTypeIndex();
String field_name = constant_pool.constantToString(index, CONSTANT_NameAndType);
if (name.equals(class_name)) { // Local field
buf.append("<A HREF=\"")
.append(class_name)
.append("_methods.html#field")
.append(field_name)
.append("\" TARGET=Methods>")
.append(field_name)
.append("</A>\n");
} else {
buf.append(constant_html.referenceConstant(class_index)).append(".").append(field_name);
}
break;
/* Operands are references to classes in constant pool
*/
case CHECKCAST:
case INSTANCEOF:
case NEW:
index = bytes.readShort();
buf.append(constant_html.referenceConstant(index));
break;
/* Operands are references to methods in constant pool
*/
case INVOKESPECIAL:
case INVOKESTATIC:
case INVOKEVIRTUAL:
case INVOKEINTERFACE:
int m_index = bytes.readShort();
String str;
if (opcode == INVOKEINTERFACE) { // Special treatment needed
int nargs = bytes.readUnsignedByte(); // Redundant
int reserved = bytes.readUnsignedByte(); // Reserved
ConstantInterfaceMethodref c =
(ConstantInterfaceMethodref)
constant_pool.getConstant(m_index, CONSTANT_InterfaceMethodref);
class_index = c.getClassIndex();
str = constant_pool.constantToString(c);
index = c.getNameAndTypeIndex();
} else {
ConstantMethodref c =
(ConstantMethodref) constant_pool.getConstant(m_index, CONSTANT_Methodref);
class_index = c.getClassIndex();
str = constant_pool.constantToString(c);
index = c.getNameAndTypeIndex();
}
name = Class2HTML.referenceClass(class_index);
str =
Class2HTML.toHTML(
constant_pool.constantToString(
constant_pool.getConstant(index, CONSTANT_NameAndType)));
// Get signature, i.e., types
ConstantNameAndType c2 =
(ConstantNameAndType) constant_pool.getConstant(index, CONSTANT_NameAndType);
signature = constant_pool.constantToString(c2.getSignatureIndex(), CONSTANT_Utf8);
String[] args = Utility.methodSignatureArgumentTypes(signature, false);
String type = Utility.methodSignatureReturnType(signature, false);
buf.append(name)
.append(".<A HREF=\"")
.append(class_name)
.append("_cp.html#cp")
.append(m_index)
.append("\" TARGET=ConstantPool>")
.append(str)
.append("</A>")
.append("(");
// List arguments
for (int i = 0; i < args.length; i++) {
buf.append(Class2HTML.referenceType(args[i]));
if (i < args.length - 1) {
buf.append(", ");
}
}
// Attach return type
buf.append("):").append(Class2HTML.referenceType(type));
break;
/* Operands are references to items in constant pool
*/
case LDC_W:
case LDC2_W:
index = bytes.readShort();
buf.append("<A HREF=\"")
.append(class_name)
.append("_cp.html#cp")
.append(index)
.append("\" TARGET=\"ConstantPool\">")
.append(
Class2HTML.toHTML(
constant_pool.constantToString(
index, constant_pool.getConstant(index).getTag())))
.append("</a>");
break;
case LDC:
index = bytes.readUnsignedByte();
buf.append("<A HREF=\"")
.append(class_name)
.append("_cp.html#cp")
.append(index)
.append("\" TARGET=\"ConstantPool\">")
.append(
Class2HTML.toHTML(
constant_pool.constantToString(
index, constant_pool.getConstant(index).getTag())))
.append("</a>");
break;
/* Array of references.
*/
case ANEWARRAY:
index = bytes.readShort();
buf.append(constant_html.referenceConstant(index));
break;
/* Multidimensional array of references.
*/
case MULTIANEWARRAY:
index = bytes.readShort();
int dimensions = bytes.readByte();
buf.append(constant_html.referenceConstant(index))
.append(":")
.append(dimensions)
.append("-dimensional");
break;
/* Increment local variable.
*/
case IINC:
if (wide) {
vindex = bytes.readShort();
constant = bytes.readShort();
wide = false;
} else {
vindex = bytes.readUnsignedByte();
constant = bytes.readByte();
}
buf.append("%").append(vindex).append(" ").append(constant);
break;
default:
if (NO_OF_OPERANDS[opcode] > 0) {
for (int i = 0; i < TYPE_OF_OPERANDS[opcode].length; i++) {
switch (TYPE_OF_OPERANDS[opcode][i]) {
case T_BYTE:
buf.append(bytes.readUnsignedByte());
break;
case T_SHORT: // Either branch or index
buf.append(bytes.readShort());
break;
case T_INT:
buf.append(bytes.readInt());
break;
default: // Never reached
System.err.println("Unreachable default case reached!");
System.exit(-1);
}
buf.append(" ");
}
}
}
buf.append("</TD>");
return buf.toString();
}
