net.sf.retrotranslator.runtime.asm
Class MethodWriter

java.lang.Object
  extended by net.sf.retrotranslator.runtime.asm.MethodWriter
All Implemented Interfaces:
MethodVisitor

 class MethodWriter
extends java.lang.Object
implements MethodVisitor

A MethodVisitor that generates methods in bytecode form. Each visit method of this class appends the bytecode corresponding to the visited instruction to a byte vector, in the order these methods are called.

Author:
Eric Bruneton, Eugene Kuleshov

Field Summary
private  int access
          Access flags of this method.
private  ByteVector annd
          The annotation default attribute of this method.
private  AnnotationWriter anns
          The runtime visible annotations of this method.
private  Attribute attrs
          The non standard attributes of the method.
private  Label blockStack
          The basic block stack used by the control flow analysis algorithm.
private  int catchCount
          Number of entries in the catch table of this method.
private  Handler catchTable
          The catch table of this method.
private  Attribute cattrs
          The non standard attributes of the method's code.
(package private)  int classReaderLength
          If not zero, indicates that the code of this method must be copied from the ClassReader associated to this writer in cw.cr.
(package private)  int classReaderOffset
          If not zero, indicates that the code of this method must be copied from the ClassReader associated to this writer in cw.cr.
private  ByteVector code
          The bytecode of this method.
private  boolean computeMaxs
          true if the maximum stack size and number of local variables must be automatically computed.
private  Label currentBlock
          The current basic block.
(package private)  ClassWriter cw
          The class writer to which this method must be added.
private  int desc
          The index of the constant pool item that contains the descriptor of this method.
private  java.lang.String descriptor
          The descriptor of this method.
(package private)  int exceptionCount
          Number of exceptions that can be thrown by this method.
(package private)  int[] exceptions
          The exceptions that can be thrown by this method.
private  AnnotationWriter ianns
          The runtime invisible annotations of this method.
private  AnnotationWriter[] ipanns
          The runtime invisible parameter annotations of this method.
private  Handler lastHandler
          The last element in the catchTable handler list.
private  ByteVector lineNumber
          The LineNumberTable attribute.
private  int lineNumberCount
          Number of entries in the LineNumberTable attribute.
private  ByteVector localVar
          The LocalVariableTable attribute.
private  int localVarCount
          Number of entries in the LocalVariableTable attribute.
private  ByteVector localVarType
          The LocalVariableTypeTable attribute.
private  int localVarTypeCount
          Number of entries in the LocalVariableTypeTable attribute.
private  int maxLocals
          Maximum number of local variables for this method.
private  int maxStack
          Maximum stack size of this method.
private  int maxStackSize
          The (relative) maximum stack size after the last visited instruction.
private  int name
          The index of the constant pool item that contains the name of this method.
(package private)  MethodWriter next
          Next method writer (see firstMethod).
private  AnnotationWriter[] panns
          The runtime visible parameter annotations of this method.
private  boolean resize
          Indicates if some jump instructions are too small and need to be resized.
(package private)  java.lang.String signature
          The signature of this method.
private static int[] SIZE
          The stack size variation corresponding to each JVM instruction.
private  int stackSize
          The (relative) stack size after the last visited instruction.
 
Constructor Summary
MethodWriter(ClassWriter cw, int access, java.lang.String name, java.lang.String desc, java.lang.String signature, java.lang.String[] exceptions, boolean computeMaxs)
          Constructs a new MethodWriter.
 
Method Summary
private  void addSuccessor(int stackSize, Label successor)
          Adds a successor to the currentBlock block.
private static int getArgumentsAndReturnSizes(java.lang.String desc)
          Computes the size of the arguments and of the return value of a method.
(package private) static int getNewOffset(int[] indexes, int[] sizes, int begin, int end)
          Computes the future value of a bytecode offset.
(package private) static void getNewOffset(int[] indexes, int[] sizes, Label label)
          Updates the offset of the given label.
(package private)  int getSize()
          Returns the size of the bytecode of this method.
(package private)  void put(ByteVector out, boolean dropTigerFlags)
          Puts the bytecode of this method in the given byte vector.
(package private) static int readInt(byte[] b, int index)
          Reads a signed int value in the given byte array.
(package private) static short readShort(byte[] b, int index)
          Reads a signed short value in the given byte array.
(package private) static int readUnsignedShort(byte[] b, int index)
          Reads an unsigned short value in the given byte array.
private  int[] resizeInstructions(int[] indexes, int[] sizes, int len)
          Resizes the designated instructions, while keeping jump offsets and instruction addresses consistent.
 AnnotationVisitor visitAnnotation(java.lang.String desc, boolean visible)
          Visits an annotation of this method.
 AnnotationVisitor visitAnnotationDefault()
          Visits the default value of this annotation interface method.
 void visitAttribute(Attribute attr)
          Visits a non standard attribute of this method.
 void visitCode()
          Starts the visit of the method's code, if any (i.e.
 void visitEnd()
          Visits the end of the method.
 void visitFieldInsn(int opcode, java.lang.String owner, java.lang.String name, java.lang.String desc)
          Visits a field instruction.
 void visitIincInsn(int var, int increment)
          Visits an IINC instruction.
 void visitInsn(int opcode)
          Visits a zero operand instruction.
 void visitIntInsn(int opcode, int operand)
          Visits an instruction with a single int operand.
 void visitJumpInsn(int opcode, Label label)
          Visits a jump instruction.
 void visitLabel(Label label)
          Visits a label.
 void visitLdcInsn(java.lang.Object cst)
          Visits a LDC instruction.
 void visitLineNumber(int line, Label start)
          Visits a line number declaration.
 void visitLocalVariable(java.lang.String name, java.lang.String desc, java.lang.String signature, Label start, Label end, int index)
          Visits a local variable declaration.
 void visitLookupSwitchInsn(Label dflt, int[] keys, Label[] labels)
          Visits a LOOKUPSWITCH instruction.
 void visitMaxs(int maxStack, int maxLocals)
          Visits the maximum stack size and the maximum number of local variables of the method.
 void visitMethodInsn(int opcode, java.lang.String owner, java.lang.String name, java.lang.String desc)
          Visits a method instruction.
 void visitMultiANewArrayInsn(java.lang.String desc, int dims)
          Visits a MULTIANEWARRAY instruction.
 AnnotationVisitor visitParameterAnnotation(int parameter, java.lang.String desc, boolean visible)
          Visits an annotation of a parameter this method.
 void visitTableSwitchInsn(int min, int max, Label dflt, Label[] labels)
          Visits a TABLESWITCH instruction.
 void visitTryCatchBlock(Label start, Label end, Label handler, java.lang.String type)
          Visits a try catch block.
 void visitTypeInsn(int opcode, java.lang.String desc)
          Visits a type instruction.
 void visitVarInsn(int opcode, int var)
          Visits a local variable instruction.
(package private) static void writeShort(byte[] b, int index, int s)
          Writes a short value in the given byte array.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

next

MethodWriter next
Next method writer (see firstMethod).


cw

ClassWriter cw
The class writer to which this method must be added.


access

private int access
Access flags of this method.


name

private int name
The index of the constant pool item that contains the name of this method.


desc

private int desc
The index of the constant pool item that contains the descriptor of this method.


descriptor

private java.lang.String descriptor
The descriptor of this method.


classReaderOffset

int classReaderOffset
If not zero, indicates that the code of this method must be copied from the ClassReader associated to this writer in cw.cr. More precisely, this field gives the index of the first byte to copied from cw.cr.b.


classReaderLength

int classReaderLength
If not zero, indicates that the code of this method must be copied from the ClassReader associated to this writer in cw.cr. More precisely, this field gives the number of bytes to copied from cw.cr.b.


signature

java.lang.String signature
The signature of this method.


exceptionCount

int exceptionCount
Number of exceptions that can be thrown by this method.


exceptions

int[] exceptions
The exceptions that can be thrown by this method. More precisely, this array contains the indexes of the constant pool items that contain the internal names of these exception classes.


annd

private ByteVector annd
The annotation default attribute of this method. May be null.


anns

private AnnotationWriter anns
The runtime visible annotations of this method. May be null.


ianns

private AnnotationWriter ianns
The runtime invisible annotations of this method. May be null.


panns

private AnnotationWriter[] panns
The runtime visible parameter annotations of this method. May be null.


ipanns

private AnnotationWriter[] ipanns
The runtime invisible parameter annotations of this method. May be null.


attrs

private Attribute attrs
The non standard attributes of the method.


code

private ByteVector code
The bytecode of this method.


maxStack

private int maxStack
Maximum stack size of this method.


maxLocals

private int maxLocals
Maximum number of local variables for this method.


catchCount

private int catchCount
Number of entries in the catch table of this method.


catchTable

private Handler catchTable
The catch table of this method.


lastHandler

private Handler lastHandler
The last element in the catchTable handler list.


localVarCount

private int localVarCount
Number of entries in the LocalVariableTable attribute.


localVar

private ByteVector localVar
The LocalVariableTable attribute.


localVarTypeCount

private int localVarTypeCount
Number of entries in the LocalVariableTypeTable attribute.


localVarType

private ByteVector localVarType
The LocalVariableTypeTable attribute.


lineNumberCount

private int lineNumberCount
Number of entries in the LineNumberTable attribute.


lineNumber

private ByteVector lineNumber
The LineNumberTable attribute.


cattrs

private Attribute cattrs
The non standard attributes of the method's code.


resize

private boolean resize
Indicates if some jump instructions are too small and need to be resized.


computeMaxs

private final boolean computeMaxs
true if the maximum stack size and number of local variables must be automatically computed.


stackSize

private int stackSize
The (relative) stack size after the last visited instruction. This size is relative to the beginning of the current basic block, i.e., the true stack size after the last visited instruction is equal to the beginStackSize of the current basic block plus stackSize.


maxStackSize

private int maxStackSize
The (relative) maximum stack size after the last visited instruction. This size is relative to the beginning of the current basic block, i.e., the true maximum stack size after the last visited instruction is equal to the beginStackSize of the current basic block plus stackSize.


currentBlock

private Label currentBlock
The current basic block. This block is the basic block to which the next instruction to be visited must be added.


blockStack

private Label blockStack
The basic block stack used by the control flow analysis algorithm. This stack is represented by a linked list of Label objects, linked to each other by their Label.next field. This stack must not be confused with the JVM stack used to execute the JVM instructions!


SIZE

private static final int[] SIZE
The stack size variation corresponding to each JVM instruction. This stack variation is equal to the size of the values produced by an instruction, minus the size of the values consumed by this instruction.

Constructor Detail

MethodWriter

MethodWriter(ClassWriter cw,
             int access,
             java.lang.String name,
             java.lang.String desc,
             java.lang.String signature,
             java.lang.String[] exceptions,
             boolean computeMaxs)
Constructs a new MethodWriter.

Parameters:
cw - the class writer in which the method must be added.
access - the method's access flags (see Opcodes).
name - the method's name.
desc - the method's descriptor (see Type).
signature - the method's signature. May be null.
exceptions - the internal names of the method's exceptions. May be null.
computeMaxs - true if the maximum stack size and number of local variables must be automatically computed.
Method Detail

visitAnnotationDefault

public AnnotationVisitor visitAnnotationDefault()
Description copied from interface: MethodVisitor
Visits the default value of this annotation interface method.

Specified by:
visitAnnotationDefault in interface MethodVisitor
Returns:
a non null visitor to the visit the actual default value of this annotation interface method. The 'name' parameters passed to the methods of this annotation visitor are ignored. Moreover, exacly one visit method must be called on this annotation visitor, followed by visitEnd.

visitAnnotation

public AnnotationVisitor visitAnnotation(java.lang.String desc,
                                         boolean visible)
Description copied from interface: MethodVisitor
Visits an annotation of this method.

Specified by:
visitAnnotation in interface MethodVisitor
Parameters:
desc - the class descriptor of the annotation class.
visible - true if the annotation is visible at runtime.
Returns:
a non null visitor to visit the annotation values.

visitParameterAnnotation

public AnnotationVisitor visitParameterAnnotation(int parameter,
                                                  java.lang.String desc,
                                                  boolean visible)
Description copied from interface: MethodVisitor
Visits an annotation of a parameter this method.

Specified by:
visitParameterAnnotation in interface MethodVisitor
Parameters:
parameter - the parameter index.
desc - the class descriptor of the annotation class.
visible - true if the annotation is visible at runtime.
Returns:
a non null visitor to visit the annotation values.

visitAttribute

public void visitAttribute(Attribute attr)
Description copied from interface: MethodVisitor
Visits a non standard attribute of this method.

Specified by:
visitAttribute in interface MethodVisitor
Parameters:
attr - an attribute.

visitCode

public void visitCode()
Description copied from interface: MethodVisitor
Starts the visit of the method's code, if any (i.e. non abstract method).

Specified by:
visitCode in interface MethodVisitor

visitInsn

public void visitInsn(int opcode)
Description copied from interface: MethodVisitor
Visits a zero operand instruction.

Specified by:
visitInsn in interface MethodVisitor
Parameters:
opcode - the opcode of the instruction to be visited. This opcode is either NOP, ACONST_NULL, ICONST_M1, ICONST_0, ICONST_1, ICONST_2, ICONST_3, ICONST_4, ICONST_5, LCONST_0, LCONST_1, FCONST_0, FCONST_1, FCONST_2, DCONST_0, DCONST_1, IALOAD, LALOAD, FALOAD, DALOAD, AALOAD, BALOAD, CALOAD, SALOAD, IASTORE, LASTORE, FASTORE, DASTORE, AASTORE, BASTORE, CASTORE, SASTORE, POP, POP2, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, SWAP, IADD, LADD, FADD, DADD, ISUB, LSUB, FSUB, DSUB, IMUL, LMUL, FMUL, DMUL, IDIV, LDIV, FDIV, DDIV, IREM, LREM, FREM, DREM, INEG, LNEG, FNEG, DNEG, ISHL, LSHL, ISHR, LSHR, IUSHR, LUSHR, IAND, LAND, IOR, LOR, IXOR, LXOR, I2L, I2F, I2D, L2I, L2F, L2D, F2I, F2L, F2D, D2I, D2L, D2F, I2B, I2C, I2S, LCMP, FCMPL, FCMPG, DCMPL, DCMPG, IRETURN, LRETURN, FRETURN, DRETURN, ARETURN, RETURN, ARRAYLENGTH, ATHROW, MONITORENTER, or MONITOREXIT.

visitIntInsn

public void visitIntInsn(int opcode,
                         int operand)
Description copied from interface: MethodVisitor
Visits an instruction with a single int operand.

Specified by:
visitIntInsn in interface MethodVisitor
Parameters:
opcode - the opcode of the instruction to be visited. This opcode is either BIPUSH, SIPUSH or NEWARRAY.
operand - the operand of the instruction to be visited.
When opcode is BIPUSH, operand value should be between Byte.MIN_VALUE and Byte.MAX_VALUE.
When opcode is SIPUSH, operand value should be between Short.MIN_VALUE and Short.MAX_VALUE.
When opcode is NEWARRAY, operand value should be one of Opcodes.T_BOOLEAN, Opcodes.T_CHAR, Opcodes.T_FLOAT, Opcodes.T_DOUBLE, Opcodes.T_BYTE, Opcodes.T_SHORT, Opcodes.T_INT or Opcodes.T_LONG.

visitVarInsn

public void visitVarInsn(int opcode,
                         int var)
Description copied from interface: MethodVisitor
Visits a local variable instruction. A local variable instruction is an instruction that loads or stores the value of a local variable.

Specified by:
visitVarInsn in interface MethodVisitor
Parameters:
opcode - the opcode of the local variable instruction to be visited. This opcode is either ILOAD, LLOAD, FLOAD, DLOAD, ALOAD, ISTORE, LSTORE, FSTORE, DSTORE, ASTORE or RET.
var - the operand of the instruction to be visited. This operand is the index of a local variable.

visitTypeInsn

public void visitTypeInsn(int opcode,
                          java.lang.String desc)
Description copied from interface: MethodVisitor
Visits a type instruction. A type instruction is an instruction that takes a type descriptor as parameter.

Specified by:
visitTypeInsn in interface MethodVisitor
Parameters:
opcode - the opcode of the type instruction to be visited. This opcode is either NEW, ANEWARRAY, CHECKCAST or INSTANCEOF.
desc - the operand of the instruction to be visited. This operand is must be a fully qualified class name in internal form, or the type descriptor of an array type (see Type).

visitFieldInsn

public void visitFieldInsn(int opcode,
                           java.lang.String owner,
                           java.lang.String name,
                           java.lang.String desc)
Description copied from interface: MethodVisitor
Visits a field instruction. A field instruction is an instruction that loads or stores the value of a field of an object.

Specified by:
visitFieldInsn in interface MethodVisitor
Parameters:
opcode - the opcode of the type instruction to be visited. This opcode is either GETSTATIC, PUTSTATIC, GETFIELD or PUTFIELD.
owner - the internal name of the field's owner class (see getInternalName).
name - the field's name.
desc - the field's descriptor (see Type).

visitMethodInsn

public void visitMethodInsn(int opcode,
                            java.lang.String owner,
                            java.lang.String name,
                            java.lang.String desc)
Description copied from interface: MethodVisitor
Visits a method instruction. A method instruction is an instruction that invokes a method.

Specified by:
visitMethodInsn in interface MethodVisitor
Parameters:
opcode - the opcode of the type instruction to be visited. This opcode is either INVOKEVIRTUAL, INVOKESPECIAL, INVOKESTATIC or INVOKEINTERFACE.
owner - the internal name of the method's owner class (see getInternalName).
name - the method's name.
desc - the method's descriptor (see Type).

visitJumpInsn

public void visitJumpInsn(int opcode,
                          Label label)
Description copied from interface: MethodVisitor
Visits a jump instruction. A jump instruction is an instruction that may jump to another instruction.

Specified by:
visitJumpInsn in interface MethodVisitor
Parameters:
opcode - the opcode of the type instruction to be visited. This opcode is either IFEQ, IFNE, IFLT, IFGE, IFGT, IFLE, IF_ICMPEQ, IF_ICMPNE, IF_ICMPLT, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE, IF_ACMPEQ, IF_ACMPNE, GOTO, JSR, IFNULL or IFNONNULL.
label - the operand of the instruction to be visited. This operand is a label that designates the instruction to which the jump instruction may jump.

visitLabel

public void visitLabel(Label label)
Description copied from interface: MethodVisitor
Visits a label. A label designates the instruction that will be visited just after it.

Specified by:
visitLabel in interface MethodVisitor
Parameters:
label - a Label object.

visitLdcInsn

public void visitLdcInsn(java.lang.Object cst)
Description copied from interface: MethodVisitor
Visits a LDC instruction.

Specified by:
visitLdcInsn in interface MethodVisitor
Parameters:
cst - the constant to be loaded on the stack. This parameter must be a non null Integer, a Float, a Long, a Double a String (or a Type for .class constants, for classes whose version is 49.0 or more).

visitIincInsn

public void visitIincInsn(int var,
                          int increment)
Description copied from interface: MethodVisitor
Visits an IINC instruction.

Specified by:
visitIincInsn in interface MethodVisitor
Parameters:
var - index of the local variable to be incremented.
increment - amount to increment the local variable by.

visitTableSwitchInsn

public void visitTableSwitchInsn(int min,
                                 int max,
                                 Label dflt,
                                 Label[] labels)
Description copied from interface: MethodVisitor
Visits a TABLESWITCH instruction.

Specified by:
visitTableSwitchInsn in interface MethodVisitor
Parameters:
min - the minimum key value.
max - the maximum key value.
dflt - beginning of the default handler block.
labels - beginnings of the handler blocks. labels[i] is the beginning of the handler block for the min + i key.

visitLookupSwitchInsn

public void visitLookupSwitchInsn(Label dflt,
                                  int[] keys,
                                  Label[] labels)
Description copied from interface: MethodVisitor
Visits a LOOKUPSWITCH instruction.

Specified by:
visitLookupSwitchInsn in interface MethodVisitor
Parameters:
dflt - beginning of the default handler block.
keys - the values of the keys.
labels - beginnings of the handler blocks. labels[i] is the beginning of the handler block for the keys[i] key.

visitMultiANewArrayInsn

public void visitMultiANewArrayInsn(java.lang.String desc,
                                    int dims)
Description copied from interface: MethodVisitor
Visits a MULTIANEWARRAY instruction.

Specified by:
visitMultiANewArrayInsn in interface MethodVisitor
Parameters:
desc - an array type descriptor (see Type).
dims - number of dimensions of the array to allocate.

visitTryCatchBlock

public void visitTryCatchBlock(Label start,
                               Label end,
                               Label handler,
                               java.lang.String type)
Description copied from interface: MethodVisitor
Visits a try catch block.

Specified by:
visitTryCatchBlock in interface MethodVisitor
Parameters:
start - beginning of the exception handler's scope (inclusive).
end - end of the exception handler's scope (exclusive).
handler - beginning of the exception handler's code.
type - internal name of the type of exceptions handled by the handler, or null to catch any exceptions (for "finally" blocks).

visitLocalVariable

public void visitLocalVariable(java.lang.String name,
                               java.lang.String desc,
                               java.lang.String signature,
                               Label start,
                               Label end,
                               int index)
Description copied from interface: MethodVisitor
Visits a local variable declaration.

Specified by:
visitLocalVariable in interface MethodVisitor
Parameters:
name - the name of a local variable.
desc - the type descriptor of this local variable.
signature - the type signature of this local variable. May be null if the local variable type does not use generic types.
start - the first instruction corresponding to the scope of this local variable (inclusive).
end - the last instruction corresponding to the scope of this local variable (exclusive).
index - the local variable's index.

visitLineNumber

public void visitLineNumber(int line,
                            Label start)
Description copied from interface: MethodVisitor
Visits a line number declaration.

Specified by:
visitLineNumber in interface MethodVisitor
Parameters:
line - a line number. This number refers to the source file from which the class was compiled.
start - the first instruction corresponding to this line number.

visitMaxs

public void visitMaxs(int maxStack,
                      int maxLocals)
Description copied from interface: MethodVisitor
Visits the maximum stack size and the maximum number of local variables of the method.

Specified by:
visitMaxs in interface MethodVisitor
Parameters:
maxStack - maximum stack size of the method.
maxLocals - maximum number of local variables for the method.

visitEnd

public void visitEnd()
Description copied from interface: MethodVisitor
Visits the end of the method. This method, which is the last one to be called, is used to inform the visitor that all the annotations and attributes of the method have been visited.

Specified by:
visitEnd in interface MethodVisitor

getArgumentsAndReturnSizes

private static int getArgumentsAndReturnSizes(java.lang.String desc)
Computes the size of the arguments and of the return value of a method.

Parameters:
desc - the descriptor of a method.
Returns:
the size of the arguments of the method (plus one for the implicit this argument), argSize, and the size of its return value, retSize, packed into a single int i = (argSize << 2) | retSize (argSize is therefore equal to i >> 2, and retSize to i & 0x03).

addSuccessor

private void addSuccessor(int stackSize,
                          Label successor)
Adds a successor to the currentBlock block.

Parameters:
stackSize - the current (relative) stack size in the current block.
successor - the successor block to be added to the current block.

getSize

final int getSize()
Returns the size of the bytecode of this method.

Returns:
the size of the bytecode of this method.

put

final void put(ByteVector out,
               boolean dropTigerFlags)
Puts the bytecode of this method in the given byte vector.

Parameters:
out - the byte vector into which the bytecode of this method must be
dropTigerFlags -

resizeInstructions

private int[] resizeInstructions(int[] indexes,
                                 int[] sizes,
                                 int len)
Resizes the designated instructions, while keeping jump offsets and instruction addresses consistent. This may require to resize other existing instructions, or even to introduce new instructions: for example, increasing the size of an instruction by 2 at the middle of a method can increases the offset of an IFEQ instruction from 32766 to 32768, in which case IFEQ 32766 must be replaced with IFNEQ 8 GOTO_W 32765. This, in turn, may require to increase the size of another jump instruction, and so on... All these operations are handled automatically by this method.

This method must be called after all the method that is being built has been visited. In particular, the Label objects used to construct the method are no longer valid after this method has been called.

Parameters:
indexes - current positions of the instructions to be resized. Each instruction must be designated by the index of its last byte, plus one (or, in other words, by the index of the first byte of the next instruction).
sizes - the number of bytes to be added to the above instructions. More precisely, for each i < len, sizes[i] bytes will be added at the end of the instruction designated by indexes[i] or, if sizes[i] is negative, the last |sizes[i]| bytes of the instruction will be removed (the instruction size must not become negative or null). The gaps introduced by this method must be filled in "manually" in code method.
len - the number of instruction to be resized. Must be smaller than or equal to indexes.length and sizes.length.
Returns:
the indexes array, which now contains the new positions of the resized instructions (designated as above).

readUnsignedShort

static int readUnsignedShort(byte[] b,
                             int index)
Reads an unsigned short value in the given byte array.

Parameters:
b - a byte array.
index - the start index of the value to be read.
Returns:
the read value.

readShort

static short readShort(byte[] b,
                       int index)
Reads a signed short value in the given byte array.

Parameters:
b - a byte array.
index - the start index of the value to be read.
Returns:
the read value.

readInt

static int readInt(byte[] b,
                   int index)
Reads a signed int value in the given byte array.

Parameters:
b - a byte array.
index - the start index of the value to be read.
Returns:
the read value.

writeShort

static void writeShort(byte[] b,
                       int index,
                       int s)
Writes a short value in the given byte array.

Parameters:
b - a byte array.
index - where the first byte of the short value must be written.
s - the value to be written in the given byte array.

getNewOffset

static int getNewOffset(int[] indexes,
                        int[] sizes,
                        int begin,
                        int end)
Computes the future value of a bytecode offset.

Note: it is possible to have several entries for the same instruction in the indexes and sizes: two entries (index=a,size=b) and (index=a,size=b') are equivalent to a single entry (index=a,size=b+b').

Parameters:
indexes - current positions of the instructions to be resized. Each instruction must be designated by the index of its last byte, plus one (or, in other words, by the index of the first byte of the next instruction).
sizes - the number of bytes to be added to the above instructions. More precisely, for each i < len, sizes[i] bytes will be added at the end of the instruction designated by indexes[i] or, if sizes[i] is negative, the last |sizes[i]| bytes of the instruction will be removed (the instruction size must not become negative or null).
begin - index of the first byte of the source instruction.
end - index of the first byte of the target instruction.
Returns:
the future value of the given bytecode offset.

getNewOffset

static void getNewOffset(int[] indexes,
                         int[] sizes,
                         Label label)
Updates the offset of the given label.

Parameters:
indexes - current positions of the instructions to be resized. Each instruction must be designated by the index of its last byte, plus one (or, in other words, by the index of the first byte of the next instruction).
sizes - the number of bytes to be added to the above instructions. More precisely, for each i < len, sizes[i] bytes will be added at the end of the instruction designated by indexes[i] or, if sizes[i] is negative, the last |sizes[i]| bytes of the instruction will be removed (the instruction size must not become negative or null).
label - the label whose offset must be updated.