| /* Copyright (C) 2003 Vladimir Roubtsov. All rights reserved. |
| * |
| * This program and the accompanying materials are made available under |
| * the terms of the Common Public License v1.0 which accompanies this distribution, |
| * and is available at http://www.eclipse.org/legal/cpl-v10.html |
| * |
| * $Id: CodeAttribute_info.java,v 1.1.1.1 2004/05/09 16:57:47 vlad_r Exp $ |
| */ |
| package com.vladium.jcd.cls.attribute; |
| |
| import java.io.IOException; |
| |
| import com.vladium.jcd.cls.ElementFactory; |
| import com.vladium.jcd.cls.IAttributeCollection; |
| import com.vladium.jcd.cls.IConstantCollection; |
| import com.vladium.jcd.lib.UDataInputStream; |
| import com.vladium.jcd.lib.UDataOutputStream; |
| |
| // ---------------------------------------------------------------------------- |
| /** |
| * The Code attribute is a variable-length attribute used in the attributes |
| * table of {@link com.vladium.jcd.cls.Method_info} structures. A Code attribute |
| * contains the JVM instructions and auxiliary information for a single Java method, |
| * instance initialization method, or class or interface initialization method. |
| * Every Java Virtual Machine implementation must recognize Code attributes. There |
| * must be exactly one Code attribute in each method_info structure.<P> |
| * |
| * The Code attribute has the format |
| * <PRE> |
| * Code_attribute { |
| * u2 attribute_name_index; |
| * u4 attribute_length; |
| * u2 max_stack; |
| * u2 max_locals; |
| * u4 code_length; |
| * u1 code[code_length]; |
| * u2 exception_table_length; |
| * { u2 start_pc; |
| * u2 end_pc; |
| * u2 handler_pc; |
| * u2 catch_type; |
| * } exception_table[exception_table_length]; |
| * |
| * u2 attributes_count; |
| * attribute_info attributes[attributes_count]; |
| * } |
| * </PRE> |
| * |
| * The value of the max_stack item gives the maximum number of words on the operand |
| * stack at any point during execution of this method.<P> |
| * |
| * The value of the max_locals item gives the number of local variables used by this |
| * method, including the parameters passed to the method on invocation. The index of |
| * the first local variable is 0 . The greatest local variable index for a one-word |
| * value is max_locals-1 . The greatest local variable index for a two-word value is |
| * max_locals-2.<P> |
| * |
| * The value of the code_length item gives the number of bytes in the code array for |
| * this method. The value of code_length must be greater than zero; the code array must |
| * not be empty.The code array gives the actual bytes of Java Virtual Machine code that |
| * implement the method.<P> |
| * |
| * The value of the exception_table_length item gives the number of entries in the |
| * exception_table table. Each entry in the exception_table array describes one |
| * exception handler in the code array: see {@link Exception_info}.<P> |
| * |
| * The value of the attributes_count item indicates the number of attributes of the Code |
| * attribute. Each value of the attributes table must be a variable-length attribute |
| * structure. A Code attribute can have any number of optional attributes associated |
| * with it. |
| * |
| * @author (C) 2001, Vlad Roubtsov |
| */ |
| public |
| final class CodeAttribute_info extends Attribute_info |
| { |
| // public: ................................................................ |
| |
| |
| public static final byte [] EMPTY_BYTE_ARRAY = new byte [0]; |
| |
| public int m_max_stack, m_max_locals; |
| |
| |
| |
| public CodeAttribute_info (final int attribute_name_index, |
| final int max_stack, int max_locals, |
| final byte [] code, |
| final IExceptionHandlerTable exceptionHandlerTable, |
| final IAttributeCollection attributes) |
| { |
| super (attribute_name_index, 8 + (code != null ? code.length : 0) + exceptionHandlerTable.length () + attributes.length ()); |
| |
| m_max_stack = max_stack; |
| m_max_locals = max_locals; |
| |
| m_code = (code != null ? code : EMPTY_BYTE_ARRAY); |
| m_codeSize = m_code.length; |
| |
| m_exceptionHandlerTable = exceptionHandlerTable; |
| m_attributes = attributes; |
| } |
| |
| /** |
| * NOTE: must also use getCodeSize() |
| * @return |
| */ |
| public final byte [] getCode () |
| { |
| return m_code; |
| } |
| |
| public final int getCodeSize () |
| { |
| return m_codeSize; |
| } |
| |
| public IAttributeCollection getAttributes () |
| { |
| return m_attributes; |
| } |
| |
| public IExceptionHandlerTable getExceptionTable () |
| { |
| return m_exceptionHandlerTable; |
| } |
| |
| public long length () |
| { |
| return 14 + m_codeSize + m_exceptionHandlerTable.length () + m_attributes.length (); |
| } |
| |
| // Visitor: |
| |
| public void accept (final IAttributeVisitor visitor, final Object ctx) |
| { |
| visitor.visit (this, ctx); |
| } |
| |
| |
| public String toString () |
| { |
| String eol = System.getProperty ("line.separator"); |
| |
| StringBuffer s = new StringBuffer (); |
| |
| s.append ("CodeAttribute_info: [attribute_name_index = " + m_name_index + ", attribute_length = " + m_attribute_length + "]" + eol); |
| s.append (" max_stack/max_locals = " + m_max_stack + '/' + m_max_locals + eol); |
| s.append (" code [length " + m_codeSize + "]" + eol); |
| |
| for (int a = 0; a < m_attributes.size (); ++ a) |
| { |
| s.append (" " + m_attributes.get (a) + eol); |
| } |
| |
| |
| return s.toString (); |
| } |
| |
| // Cloneable: |
| |
| /** |
| * Performs a deep copy. |
| */ |
| public Object clone () |
| { |
| final CodeAttribute_info _clone = (CodeAttribute_info) super.clone (); |
| |
| // do deep copy: |
| |
| _clone.m_code = (m_codeSize == 0 ? EMPTY_BYTE_ARRAY : (byte []) m_code.clone ()); // does not trim |
| _clone.m_exceptionHandlerTable = (IExceptionHandlerTable) m_exceptionHandlerTable.clone (); |
| _clone.m_attributes = (IAttributeCollection) m_attributes.clone (); |
| |
| return _clone; |
| } |
| |
| |
| // IClassFormatOutput: |
| |
| public void writeInClassFormat (final UDataOutputStream out) throws IOException |
| { |
| super.writeInClassFormat (out); |
| |
| out.writeU2 (m_max_stack); |
| out.writeU2 (m_max_locals); |
| |
| out.writeU4 (m_codeSize); |
| out.write (m_code, 0, m_codeSize); // TODO: THIS IS WRONG |
| |
| m_exceptionHandlerTable.writeInClassFormat (out); |
| m_attributes.writeInClassFormat (out); |
| } |
| |
| |
| public void setCode (final byte [] code, final int codeSize) |
| { |
| m_code = code; |
| m_codeSize = codeSize; |
| } |
| |
| // protected: ............................................................. |
| |
| // package: ............................................................... |
| |
| |
| CodeAttribute_info (final IConstantCollection constants, |
| final int attribute_name_index, final long attribute_length, |
| final UDataInputStream bytes) |
| throws IOException |
| { |
| super (attribute_name_index, attribute_length); |
| |
| m_max_stack = bytes.readU2 (); |
| m_max_locals = bytes.readU2 (); |
| |
| final long code_length = bytes.readU4 (); |
| |
| m_code = new byte [(int) code_length]; |
| bytes.readFully (m_code); |
| m_codeSize = (int) code_length; |
| |
| |
| final int exception_table_length = bytes.readU2 (); |
| m_exceptionHandlerTable = AttributeElementFactory.newExceptionHandlerTable (exception_table_length); |
| |
| for (int i = 0; i < exception_table_length; ++ i) |
| { |
| Exception_info exception_info = new Exception_info (bytes); |
| if (DEBUG) System.out.println ("\t[" + i + "] exception: " + exception_info); |
| |
| m_exceptionHandlerTable.add (exception_info); |
| } |
| |
| |
| // TODO: put this logic into AttributeCollection |
| final int attributes_count = bytes.readU2 (); |
| m_attributes = ElementFactory.newAttributeCollection (attributes_count); |
| |
| for (int i = 0; i < attributes_count; ++ i) |
| { |
| Attribute_info attribute_info = Attribute_info.new_Attribute_info (constants, bytes); |
| if (DEBUG) System.out.println ("\t[" + i + "] attribute: " + attribute_info); |
| |
| m_attributes.add (attribute_info); |
| } |
| } |
| |
| // private: ............................................................... |
| |
| |
| private byte [] m_code; // never null [valid content extent is m_codeSize] |
| private int m_codeSize; |
| |
| private IExceptionHandlerTable m_exceptionHandlerTable; // never null |
| private IAttributeCollection m_attributes; // never null |
| |
| |
| private static final boolean DEBUG = false; |
| |
| } // end of class |
| // ---------------------------------------------------------------------------- |