javassist.bytecode

Class StackMapTable.Walker

java.lang.Object

javassist.bytecode.StackMapTable.Walker

Direct Known Subclasses:

StackMapTable.OffsetShifter, StackMapTable.Printer, StackMapTable.Shifter, StackMapTable.SimpleCopy

Enclosing class:

StackMapTable

public static class StackMapTable.Walker
extends java.lang.Object

A code walker for a StackMapTable attribute.

Field Summary

Fields

Modifier and Type	Field and Description
(package private) byte[]	info
(package private) int	numOfEntries

Constructor Summary

Constructors

Constructor and Description
Walker(byte[] data) Constructs a walker.
Walker(StackMapTable smt) Constructs a walker.

Method Summary

Modifier and Type	Method and Description
private int	appendFrame(int pos, int type)
void	appendFrame(int pos, int offsetDelta, int[] tags, int[] data) Invoked if the visited frame is a append_frame.
void	chopFrame(int pos, int offsetDelta, int k) Invoked if the visited frame is a chop_frame.
private int	fullFrame(int pos)
void	fullFrame(int pos, int offsetDelta, int[] localTags, int[] localData, int[] stackTags, int[] stackData) Invoked if the visited frame is full_frame.
void	objectOrUninitialized(int tag, int data, int pos) Invoked if Object_variable_info or Uninitialized_variable_info is visited.
void	parse() Visits each entry of the stack map frames.
void	sameFrame(int pos, int offsetDelta) Invoked if the visited frame is a same_frame or a same_frame_extended.
private int	sameLocals(int pos, int type)
void	sameLocals(int pos, int offsetDelta, int stackTag, int stackData) Invoked if the visited frame is a same_locals_1_stack_item_frame or a same_locals_1_stack_item_frame_extended.
int	size() Returns the number of the entries.
(package private) int	stackMapFrames(int pos, int nth) Invoked when the next entry of the stack map frames is visited.
private int	verifyTypeInfo(int pos, int n, int[] tags, int[] data)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

info

byte[] info

numOfEntries

int numOfEntries

Constructor Detail

Walker

public Walker(StackMapTable smt)

Constructs a walker.

Parameters:

smt - the StackMapTable that this walker walks around.

Walker

public Walker(byte[] data)

Constructs a walker.

Parameters:

data - the info field of the attribute_info structure. It can be obtained by get() in the AttributeInfo class.

Method Detail

size

public final int size()

Returns the number of the entries.

parse

public void parse()
           throws BadBytecode

Visits each entry of the stack map frames.

Throws:

BadBytecode

stackMapFrames

int stackMapFrames(int pos,
                   int nth)
            throws BadBytecode

Invoked when the next entry of the stack map frames is visited.

Parameters:

pos - the position of the frame in the info field of attribute_info structure.

nth - the frame is the N-th (0, 1st, 2nd, 3rd, 4th, ...) entry.

Returns:

the position of the next frame.

Throws:

BadBytecode

sameFrame

public void sameFrame(int pos,
                      int offsetDelta)
               throws BadBytecode

Invoked if the visited frame is a same_frame or a same_frame_extended.

Parameters:

pos - the position of this frame in the info field of attribute_info structure.

offsetDelta -

Throws:

BadBytecode

sameLocals

private int sameLocals(int pos,
                       int type)
                throws BadBytecode

Throws:

BadBytecode

sameLocals

public void sameLocals(int pos,
                       int offsetDelta,
                       int stackTag,
                       int stackData)
                throws BadBytecode

Invoked if the visited frame is a same_locals_1_stack_item_frame or a same_locals_1_stack_item_frame_extended.

Parameters:

pos - the position.

offsetDelta -

stackTag - stack[0].tag.

stackData - stack[0].cpool_index if the tag is OBJECT, or stack[0].offset if the tag is UNINIT.

Throws:

BadBytecode

chopFrame

public void chopFrame(int pos,
                      int offsetDelta,
                      int k)
               throws BadBytecode

Invoked if the visited frame is a chop_frame.

Parameters:

pos - the position.

offsetDelta -

k - the k last locals are absent.

Throws:

BadBytecode

appendFrame

private int appendFrame(int pos,
                        int type)
                 throws BadBytecode

Throws:

BadBytecode

appendFrame

public void appendFrame(int pos,
                        int offsetDelta,
                        int[] tags,
                        int[] data)
                 throws BadBytecode

Invoked if the visited frame is a append_frame.

Parameters:

pos - the position.

offsetDelta -

tags - locals[i].tag.

data - locals[i].cpool_index or locals[i].offset.

Throws:

BadBytecode

fullFrame

private int fullFrame(int pos)
               throws BadBytecode

Throws:

BadBytecode

fullFrame

public void fullFrame(int pos,
                      int offsetDelta,
                      int[] localTags,
                      int[] localData,
                      int[] stackTags,
                      int[] stackData)
               throws BadBytecode

Invoked if the visited frame is full_frame.

Parameters:

pos - the position.

offsetDelta -

localTags - locals[i].tag

localData - locals[i].cpool_index or locals[i].offset

stackTags - stack[i].tag

stackData - stack[i].cpool_index or stack[i].offset

Throws:

BadBytecode

verifyTypeInfo

private int verifyTypeInfo(int pos,
                           int n,
                           int[] tags,
                           int[] data)

objectOrUninitialized

public void objectOrUninitialized(int tag,
                                  int data,
                                  int pos)

Invoked if Object_variable_info or Uninitialized_variable_info is visited.

Parameters:

tag - OBJECT or UNINIT.

data - the value of cpool_index or offset.

pos - the position of cpool_index or offset.