/**
* ASM: a very small and fast Java bytecode manipulation framework
* Copyright (c) 2000,2002,2003 INRIA, France Telecom
* 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. Neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS 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 COPYRIGHT OWNER OR 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.
*/
package oracle.toplink.libraries.asm.attrs;
import java.util.ArrayList;
import java.util.HashSet;
import oracle.toplink.libraries.asm.Attribute;
import oracle.toplink.libraries.asm.ByteVector;
import oracle.toplink.libraries.asm.ClassReader;
import oracle.toplink.libraries.asm.ClassWriter;
import oracle.toplink.libraries.asm.Label;
/**
* StackMapAttribute is used by CDLC preverifier and also by javac compiller
* starting from J2SE 1.5. Definition is given in appendix "CLDC Byte Code
* Typechecker Specification" from CDLC 1.1 specification.
* <p>
* <i>Note that this implementation does not calculate StackMapFrame structures
* from the method bytecode. If method code is changed or generated from scratch,
* then developer is responsible to prepare a correct StackMapFrame structures.</i>
* <p>
* The format of the stack map in the class file is given below. In the following,
* <ul>
* <li>if the length of the method's byte code1 is 65535 or less, then <tt>uoffset</tt>
* represents the type u2; otherwise <tt>uoffset</tt> represents the type u4.</li>
* <li>If the maximum number of local variables for the method is 65535 or less,
* then <tt>ulocalvar</tt> represents the type u2; otherwise <tt>ulocalvar</tt>
* represents the type u4.</li>
* <li>If the maximum size of the operand stack is 65535 or less, then <tt>ustack</tt>
* represents the type u2; otherwise ustack represents the type u4.</li>
* </ul>
*
* <pre>
* stack_map { // attribute StackMap
* u2 attribute_name_index;
* u4 attribute_length
* uoffset number_of_entries;
* stack_map_frame entries[number_of_entries];
* }
* </pre>
* Each stack map frame has the following format:
* <pre>
* stack_map_frame {
* uoffset offset;
* ulocalvar number_of_locals;
* verification_type_info locals[number_of_locals];
* ustack number_of_stack_items;
* verification_type_info stack[number_of_stack_items];
* }
* </pre>
* The <tt>verification_type_info</tt> structure consists of a one-byte tag
* followed by zero or more bytes, giving more information about the tag.
* Each <tt>verification_type_info</tt> structure specifies the verification
* type of one or two locations.
* <pre>
* union verification_type_info {
* Top_variable_info;
* Integer_variable_info;
* Float_variable_info;
* Long_variable_info;
* Double_variable_info;
* Null_variable_info;
* UninitializedThis_variable_info;
* Object_variable_info;
* Uninitialized_variable_info;
* }
*
* Top_variable_info {
* u1 tag = ITEM_Top; // 0
* }
*
* Integer_variable_info {
* u1 tag = ITEM_Integer; // 1
* }
*
* Float_variable_info {
* u1 tag = ITEM_Float; // 2
* }
*
* Long_variable_info {
* u1 tag = ITEM_Long; // 4
* }
*
* Double_variable_info {
* u1 tag = ITEM_Double; // 3
* }
*
* Null_variable_info {
* u1 tag = ITEM_Null; // 5
* }
*
* UninitializedThis_variable_info {
* u1 tag = ITEM_UninitializedThis; // 6
* }
*
* Object_variable_info {
* u1 tag = ITEM_Object; // 7
* u2 cpool_index;
* }
*
* Uninitialized_variable_info {
* u1 tag = ITEM_Uninitialized // 8
* uoffset offset;
* }
* </pre>
*
* @see <a href="http://www.jcp.org/en/jsr/detail?id=139">JSR 139 : Connected
* Limited Device Configuration 1.1</a>
*
* @author Eugene Kuleshov
*/
public class StackMapAttribute extends Attribute {
static final int MAX_SIZE = 65535;
public ArrayList frames = new ArrayList();
public StackMapAttribute () {
super("StackMap");
}
public StackMapFrame getFrame (Label label) {
for (int i = 0; i < frames.size(); i++) {
StackMapFrame frame = (StackMapFrame)frames.get(i);
if (frame.label == label) {
return frame;
}
}
return null;
}
protected Attribute read (ClassReader cr, int off, int len,
char[] buf, int codeOff, Label[] labels) {
StackMapAttribute attr = new StackMapAttribute();
// note that this is not the size of Code attribute
int codeSize = cr.readInt(codeOff + 4);
int size = 0;
if (codeSize > MAX_SIZE) {
size = cr.readInt(off);
off += 4;
} else {
size = cr.readShort(off);
off += 2;
}
for (int i = 0; i < size; i++) {
StackMapFrame frame = new StackMapFrame();
off = frame.read(cr, off, buf, codeOff, labels);
attr.frames.add(frame);
}
return attr;
}
protected ByteVector write (ClassWriter cw, byte[] code,
int len, int maxStack, int maxLocals) {
ByteVector bv = new ByteVector();
if ( code!=null && code.length > MAX_SIZE) {
bv.putInt(frames.size());
} else {
bv.putShort(frames.size());
}
for (int i = 0; i < frames.size(); i++) {
((StackMapFrame)frames.get(i)).write(cw, maxStack, maxLocals, bv);
}
return bv;
}
protected Label[] getLabels () {
HashSet labels = new HashSet();
for (int i = 0; i < frames.size(); i++) {
((StackMapFrame)frames.get(i)).getLabels(labels);
}
return (Label[])labels.toArray(new Label[labels.size()]);
}
public String toString () {
StringBuffer sb = new StringBuffer("StackMap[");
for (int i = 0; i < frames.size(); i++) {
sb.append('\n').append('[').append(frames.get(i)).append(']');
}
sb.append("\n]");
return sb.toString();
}
}