java.lang.Object
- com.ibm.wala.util.bytecode.BytecodeStream

All Implemented Interfaces:

BytecodeConstants
```
public class BytecodeStream
extends Object
implements BytecodeConstants
```
Provides minimal abstraction layer to a stream of bytecodes from the code attribute of a method.

Field Summary
- Fields inherited from interface com.ibm.wala.shrikeBT.BytecodeConstants
  JBC_aaload, JBC_aastore, JBC_aconst_null, JBC_aload, JBC_aload_0, JBC_aload_1, JBC_aload_2, JBC_aload_3, JBC_anewarray, JBC_areturn, JBC_arraylength, JBC_astore, JBC_astore_0, JBC_astore_1, JBC_astore_2, JBC_astore_3, JBC_athrow, JBC_baload, JBC_bastore, JBC_bipush, JBC_caload, JBC_castore, JBC_checkcast, JBC_d2f, JBC_d2i, JBC_d2l, JBC_dadd, JBC_daload, JBC_dastore, JBC_dcmpg, JBC_dcmpl, JBC_dconst_0, JBC_dconst_1, JBC_ddiv, JBC_dload, JBC_dload_0, JBC_dload_1, JBC_dload_2, JBC_dload_3, JBC_dmul, JBC_dneg, JBC_drem, JBC_dreturn, JBC_dstore, JBC_dstore_0, JBC_dstore_1, JBC_dstore_2, JBC_dstore_3, JBC_dsub, JBC_dup, JBC_dup_x1, JBC_dup_x2, JBC_dup2, JBC_dup2_x1, JBC_dup2_x2, JBC_f2d, JBC_f2i, JBC_f2l, JBC_fadd, JBC_faload, JBC_fastore, JBC_fcmpg, JBC_fcmpl, JBC_fconst_0, JBC_fconst_1, JBC_fconst_2, JBC_fdiv, JBC_fload, JBC_fload_0, JBC_fload_1, JBC_fload_2, JBC_fload_3, JBC_fmul, JBC_fneg, JBC_frem, JBC_freturn, JBC_fstore, JBC_fstore_0, JBC_fstore_1, JBC_fstore_2, JBC_fstore_3, JBC_fsub, JBC_getfield, JBC_getstatic, JBC_goto, JBC_goto_w, JBC_i2d, JBC_i2f, JBC_i2l, JBC_iadd, JBC_iaload, JBC_iand, JBC_iastore, JBC_iconst_0, JBC_iconst_1, JBC_iconst_2, JBC_iconst_3, JBC_iconst_4, JBC_iconst_5, JBC_iconst_m1, JBC_idiv, JBC_if_acmpeq, JBC_if_acmpne, JBC_if_icmpeq, JBC_if_icmpge, JBC_if_icmpgt, JBC_if_icmple, JBC_if_icmplt, JBC_if_icmpne, JBC_ifeq, JBC_ifge, JBC_ifgt, JBC_ifle, JBC_iflt, JBC_ifne, JBC_ifnonnull, JBC_ifnull, JBC_iinc, JBC_iload, JBC_iload_0, JBC_iload_1, JBC_iload_2, JBC_iload_3, JBC_impdep1, JBC_impdep2, JBC_imul, JBC_ineg, JBC_instanceof, JBC_int2byte, JBC_int2char, JBC_int2short, JBC_invokeinterface, JBC_invokespecial, JBC_invokestatic, JBC_invokevirtual, JBC_ior, JBC_irem, JBC_ireturn, JBC_ishl, JBC_ishr, JBC_istore, JBC_istore_0, JBC_istore_1, JBC_istore_2, JBC_istore_3, JBC_isub, JBC_iushr, JBC_ixor, JBC_jsr, JBC_jsr_w, JBC_l2d, JBC_l2f, JBC_l2i, JBC_ladd, JBC_laload, JBC_land, JBC_lastore, JBC_lcmp, JBC_lconst_0, JBC_lconst_1, JBC_ldc, JBC_ldc_w, JBC_ldc2_w, JBC_ldiv, JBC_length, JBC_lload, JBC_lload_0, JBC_lload_1, JBC_lload_2, JBC_lload_3, JBC_lmul, JBC_lneg, JBC_lookupswitch, JBC_lor, JBC_lrem, JBC_lreturn, JBC_lshl, JBC_lshr, JBC_lstore, JBC_lstore_0, JBC_lstore_1, JBC_lstore_2, JBC_lstore_3, JBC_lsub, JBC_lushr, JBC_lxor, JBC_monitorenter, JBC_monitorexit, JBC_multianewarray, JBC_name, JBC_new, JBC_newarray, JBC_nop, JBC_pop, JBC_pop2, JBC_putfield, JBC_putstatic, JBC_ret, JBC_return, JBC_saload, JBC_sastore, JBC_sipush, JBC_swap, JBC_tableswitch, JBC_wide, JBC_xxxunusedxxx

Constructor Summary

Constructors
Constructor Description

BytecodeStream(IMethod m, byte[] bc)

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`alignInvokeInterface()`	Skips the extra stuff after an invokeinterface instruction Used for invokeinterface
`void`	`alignSwitch()`	Skips the padding of a switch instruction Used for tableswitch, lookupswitch
`int`	`computeLookupSwitchOffset(int value, int num)`	Returns the offset for a given value of the lookupswitch (as a signed int) or 0 if the value is not in the table.
`int`	`computeTableSwitchOffset(int value, int low, int high)`	Returns the offset for a given value of the tableswitch (as a signed int) or 0 if the value is out of range.
`IClass`	`declaringClass()`	Returns the declaring class that this bytecode stream is from
`int`	`getArrayDimension()`	Returns the dimension of the array (as an unsigned byte) Used for multianewarray
`int`	`getArrayElementType()`	Returns the element type (primitive) of the array (as an unsigned byte) Used for newarray
`int`	`getBranchOffset()`	Returns the offset of the branch (as a signed short) Used for if, ificmp, ifacmp, goto, jsr
`int`	`getByteValue()`	Returns a signed byte value Used for bipush
`int`	`getConstantIndex()`	Returns the constant pool index of a constant (as an unsigned byte) Used for ldc
`int`	`getDefaultSwitchOffset()`	Returns the default offset of the switch (as a signed int) Used for tableswitch, lookupswitch
`int`	`getHighSwitchValue()`	Returns the highest value of the tableswitch (as a signed int) Used for tableswitch
`int`	`getIncrement()`	Returns an increment value (as a signed byte) Used for iinc
`int`	`getLocalNumber()`	Returns the number of the local (as an unsigned byte) Used for iload, lload, fload, dload, aload, istore, lstore, fstore, dstore, astore, iinc, ret
`int`	`getLookupSwitchOffset(int num)`	Returns the numbered offset of the lookupswitch (as a signed int) Used for lookupswitch The "cursor" has to be positioned at the start of the pair table NOTE: Will NOT advance cursor
`int`	`getLookupSwitchValue(int num)`	Returns the numbered value of the lookupswitch (as a signed int) Used for lookupswitch The "cursor" has to be positioned at the start of the pair table NOTE: Will NOT advance cursor
`int`	`getLowSwitchValue()`	Returns the lowest value of the tableswitch (as a signed int) Used for tableswitch
`int`	`getOpcode()`	Returns the opcode of the current instruction in the sequence Note: if skipInstruction has been called, but nextInstruction has not, this method will return the opcode of the skipped instruction!
`int`	`getShortValue()`	Returns a signed short value Used for sipush
`int`	`getSwitchLength()`	Returns the number of match-offset pairs in the lookupswitch (as a signed int) Used for lookupswitch
`int`	`getTableSwitchOffset(int num)`	Returns the numbered offset of the tableswitch (as a signed int) Used for tableswitch The "cursor" has to be positioned at the start of the offset table NOTE: Will NOT advance cursor
`int`	`getWideBranchOffset()`	Returns the wide offset of the branch (as a signed int) Used for goto_w, jsr_w
`int`	`getWideConstantIndex()`	Returns the wide constant pool index of a constant (as an unsigned short) Used for ldc_w, ldc2_w
`int`	`getWideIncrement()`	Returns an increment value (as a signed short) Used for iinc prefixed by wide
`int`	`getWideLocalNumber()`	Returns the wide number of the local (as an unsigned short) Used for iload, lload, fload, dload, aload, istore, lstore, fstore, dstore, astore, iinc prefixed by wide
`int`	`getWideOpcode()`	Returns the opcode of the wide instruction Used for wide Can be one of iload, lload, fload, dload, aload, istore, lstore, fstore, dstore, astore, iinc
`boolean`	`hasMoreBytecodes()`	Does the stream have more bytecodes in it?
`int`	`index()`	Returns the current bytecode index
`boolean`	`isWide()`	Are we currently processing a wide instruction?
`int`	`length()`	Returns the length of the bytecode stream Returns 0 if the method doesn't have any bytecodes (i.e.
`IMethod`	`method()`	Returns the method that this bytecode stream is from
`int`	`nextInstruction()`	Sets up the next instruction in the sequence
`int`	`peekNextOpcode()`	Returns the opcode of the next instruction in the sequence without advancing to it
`void`	`reset()`	Resets the stream to the beginning
`void`	`reset(int index)`	Resets the stream to a given position Use with caution
`void`	`skipInstruction()`	Skips the current instruction
`void`	`skipInstruction(int opc, boolean w)`	Skips the current instruction (without using the opcode field) A slightly optimized version of skipInstruction()
`void`	`skipLookupSwitchPairs(int num)`	Skips the match-offset pairs of a lookupswitch instruction Used for lookupswitch
`void`	`skipTableSwitchOffsets(int num)`	Skips the offsets of a tableswitch instruction Used for tableswitch

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - BytecodeStream
```
public BytecodeStream(IMethod m,
                      byte[] bc)
```
    Parameters:
    
    m - the method containing the bytecodes
    
    bc - the array of bytecodes
    
    Throws:
    
    IllegalArgumentException - if bc is null
    
    IllegalArgumentException - if m is null
- Method Detail
  - method
```
public final IMethod method()
```
    Returns the method that this bytecode stream is from
  - declaringClass
```
public final IClass declaringClass()
```
    Returns the declaring class that this bytecode stream is from
  - length
```
public final int length()
```
    Returns the length of the bytecode stream Returns 0 if the method doesn't have any bytecodes (i.e. is abstract or native)
  - index
```
public final int index()
```
    Returns the current bytecode index
  - reset
```
public final void reset()
```
    Resets the stream to the beginning
  - reset
```
public final void reset(int index)
```
    Resets the stream to a given position Use with caution
    
    Parameters:
    
    index - the position to reset the stream to
  - hasMoreBytecodes
```
public final boolean hasMoreBytecodes()
```
    Does the stream have more bytecodes in it?
  - peekNextOpcode
```
public final int peekNextOpcode()
```
    Returns the opcode of the next instruction in the sequence without advancing to it
    
    Returns:
    
    the opcode of the next instruction
    
    See Also:
    
    nextInstruction()
  - nextInstruction
```
public final int nextInstruction()
```
    Sets up the next instruction in the sequence
    
    Returns:
    
    the opcode of the next instruction
    
    See Also:
    
    peekNextOpcode()
  - getOpcode
```
public final int getOpcode()
```
    Returns the opcode of the current instruction in the sequence Note: if skipInstruction has been called, but nextInstruction has not, this method will return the opcode of the skipped instruction!
    
    Returns:
    
    the opcode of the current instruction
    
    See Also:
    
    nextInstruction(), isWide()
  - isWide
```
public final boolean isWide()
```
    Are we currently processing a wide instruction?
    
    Returns:
    
    true if current instruction is wide
    
    See Also:
    
    nextInstruction(), getOpcode()
  - skipInstruction
```
public final void skipInstruction()
```
    Skips the current instruction
    
    See Also:
    
    skipInstruction(int,boolean)
  - skipInstruction
```
public final void skipInstruction(int opc,
                                  boolean w)
```
    Skips the current instruction (without using the opcode field) A slightly optimized version of skipInstruction()
    
    Parameters:
    
    opc - current opcode
    
    w - whether current instruction follows wide
    
    See Also:
    
    skipInstruction()
  - getByteValue
```
public final int getByteValue()
```
    Returns a signed byte value Used for bipush
    
    Returns:
    
    signed byte value
  - getShortValue
```
public final int getShortValue()
```
    Returns a signed short value Used for sipush
    
    Returns:
    
    signed short value
  - getLocalNumber
```
public final int getLocalNumber()
```
    Returns the number of the local (as an unsigned byte) Used for iload, lload, fload, dload, aload, istore, lstore, fstore, dstore, astore, iinc, ret
    
    Returns:
    
    local number
    
    See Also:
    
    getWideLocalNumber()
  - getWideLocalNumber
```
public final int getWideLocalNumber()
```
    Returns the wide number of the local (as an unsigned short) Used for iload, lload, fload, dload, aload, istore, lstore, fstore, dstore, astore, iinc prefixed by wide
    
    Returns:
    
    wide local number
    
    See Also:
    
    getLocalNumber()
  - getIncrement
```
public final int getIncrement()
```
    Returns an increment value (as a signed byte) Used for iinc
    
    Returns:
    
    increment
    
    See Also:
    
    getWideIncrement()
  - getWideIncrement
```
public final int getWideIncrement()
```
    Returns an increment value (as a signed short) Used for iinc prefixed by wide
    
    Returns:
    
    wide increment
    
    See Also:
    
    getIncrement()
  - getBranchOffset
```
public final int getBranchOffset()
```
    Returns the offset of the branch (as a signed short) Used for if, ificmp, ifacmp, goto, jsr
    
    Returns:
    
    branch offset
    
    See Also:
    
    getWideBranchOffset()
  - getWideBranchOffset
```
public final int getWideBranchOffset()
```
    Returns the wide offset of the branch (as a signed int) Used for goto_w, jsr_w
    
    Returns:
    
    wide branch offset
    
    See Also:
    
    getBranchOffset()
  - alignSwitch
```
public final void alignSwitch()
```
    Skips the padding of a switch instruction Used for tableswitch, lookupswitch
  - getDefaultSwitchOffset
```
public final int getDefaultSwitchOffset()
```
    Returns the default offset of the switch (as a signed int) Used for tableswitch, lookupswitch
    
    Returns:
    
    default switch offset
  - getLowSwitchValue
```
public final int getLowSwitchValue()
```
    Returns the lowest value of the tableswitch (as a signed int) Used for tableswitch
    
    Returns:
    
    lowest switch value
    
    See Also:
    
    getHighSwitchValue()
  - getHighSwitchValue
```
public final int getHighSwitchValue()
```
    Returns the highest value of the tableswitch (as a signed int) Used for tableswitch
    
    Returns:
    
    highest switch value
    
    See Also:
    
    getLowSwitchValue()
  - skipTableSwitchOffsets
```
public final void skipTableSwitchOffsets(int num)
```
    Skips the offsets of a tableswitch instruction Used for tableswitch
    
    Parameters:
    
    num - the number of offsets to skip
    
    See Also:
    
    getTableSwitchOffset(int)
  - getTableSwitchOffset
```
public final int getTableSwitchOffset(int num)
```
    Returns the numbered offset of the tableswitch (as a signed int) Used for tableswitch The "cursor" has to be positioned at the start of the offset table NOTE: Will NOT advance cursor
    
    Parameters:
    
    num - the number of the offset to retrieve
    
    Returns:
    
    switch offset
  - computeTableSwitchOffset
```
public final int computeTableSwitchOffset(int value,
                                          int low,
                                          int high)
```
    Returns the offset for a given value of the tableswitch (as a signed int) or 0 if the value is out of range. Used for tableswitch The "cursor" has to be positioned at the start of the offset table NOTE: Will NOT advance cursor
    
    Parameters:
    
    value - the value to retrieve offset for
    
    low - the lowest value of the tableswitch
    
    high - the highest value of the tableswitch
    
    Returns:
    
    switch offset
  - getSwitchLength
```
public final int getSwitchLength()
```
    Returns the number of match-offset pairs in the lookupswitch (as a signed int) Used for lookupswitch
    
    Returns:
    
    number of switch pairs
  - skipLookupSwitchPairs
```
public final void skipLookupSwitchPairs(int num)
```
    Skips the match-offset pairs of a lookupswitch instruction Used for lookupswitch
    
    Parameters:
    
    num - the number of match-offset pairs to skip
    
    See Also:
    
    getLookupSwitchValue(int), getLookupSwitchOffset(int)
  - getLookupSwitchOffset
```
public final int getLookupSwitchOffset(int num)
```
    Returns the numbered offset of the lookupswitch (as a signed int) Used for lookupswitch The "cursor" has to be positioned at the start of the pair table NOTE: Will NOT advance cursor
    
    Parameters:
    
    num - the number of the offset to retrieve
    
    Returns:
    
    switch offset
    
    See Also:
    
    getLookupSwitchValue(int)
  - getLookupSwitchValue
```
public final int getLookupSwitchValue(int num)
```
    Returns the numbered value of the lookupswitch (as a signed int) Used for lookupswitch The "cursor" has to be positioned at the start of the pair table NOTE: Will NOT advance cursor
    
    Parameters:
    
    num - the number of the value to retrieve
    
    Returns:
    
    switch value
    
    See Also:
    
    getLookupSwitchOffset(int)
  - computeLookupSwitchOffset
```
public final int computeLookupSwitchOffset(int value,
                                           int num)
```
    Returns the offset for a given value of the lookupswitch (as a signed int) or 0 if the value is not in the table. Used for lookupswitch The "cursor" has to be positioned at the start of the offset table NOTE: Will NOT advance cursor WARNING: Uses LINEAR search. Whoever has time on their hands can re-implement this as a binary search.
    
    Parameters:
    
    value - the value to retrieve offset for
    
    num - the number of match-offset pairs in the lookupswitch
    
    Returns:
    
    switch offset
  - alignInvokeInterface
```
public final void alignInvokeInterface()
```
    Skips the extra stuff after an invokeinterface instruction Used for invokeinterface
  - getArrayElementType
```
public final int getArrayElementType()
```
    Returns the element type (primitive) of the array (as an unsigned byte) Used for newarray
    
    Returns:
    
    array element type
  - getArrayDimension
```
public final int getArrayDimension()
```
    Returns the dimension of the array (as an unsigned byte) Used for multianewarray
    
    Returns:
    
    array dimension
  - getWideOpcode
```
public final int getWideOpcode()
```
    Returns the opcode of the wide instruction Used for wide Can be one of iload, lload, fload, dload, aload, istore, lstore, fstore, dstore, astore, iinc
    
    Returns:
    
    the opcode of the wide instruction
  - getConstantIndex
```
public final int getConstantIndex()
```
    Returns the constant pool index of a constant (as an unsigned byte) Used for ldc
    
    Returns:
    
    constant index
    
    See Also:
    
    getWideConstantIndex()
  - getWideConstantIndex
```
public final int getWideConstantIndex()
```
    Returns the wide constant pool index of a constant (as an unsigned short) Used for ldc_w, ldc2_w
    
    Returns:
    
    wide constant index
    
    See Also:
    
    getConstantIndex()

Class BytecodeStream

Field Summary

Fields inherited from interface com.ibm.wala.shrikeBT.BytecodeConstants

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

BytecodeStream

Method Detail

method

declaringClass

length

index

reset

reset

hasMoreBytecodes

peekNextOpcode

nextInstruction

getOpcode

isWide

skipInstruction

skipInstruction

getByteValue

getShortValue

getLocalNumber

getWideLocalNumber

getIncrement

getWideIncrement

getBranchOffset

getWideBranchOffset

alignSwitch

getDefaultSwitchOffset

getLowSwitchValue

getHighSwitchValue

skipTableSwitchOffsets

getTableSwitchOffset

computeTableSwitchOffset

getSwitchLength

skipLookupSwitchPairs

getLookupSwitchOffset

getLookupSwitchValue

computeLookupSwitchOffset

alignInvokeInterface

getArrayElementType

getArrayDimension

getWideOpcode

getConstantIndex

getWideConstantIndex