Module kala.compress.compressors.pack200
Package kala.compress.harmony.unpack200.bytecode

Class ByteCode

java.lang.Object
kala.compress.harmony.unpack200.bytecode.ClassFileEntry
kala.compress.harmony.unpack200.bytecode.ByteCode
public class ByteCode extends ClassFileEntry
A bytecode class file entry.

  • Field Details

    • noArgByteCodes

      private static ByteCode[] noArgByteCodes

    • byteCodeForm

      private final ByteCodeForm byteCodeForm

    • nested

      private ClassFileEntry[] nested

    • nestedPositions

      private int[][] nestedPositions

    • rewrite

      private int[] rewrite

    • byteCodeOffset

      private int byteCodeOffset

    • byteCodeTargets

      private int[] byteCodeTargets

  • Constructor Details

    • ByteCode

      protected ByteCode(int opcode)

    • ByteCode

      protected ByteCode(int opcode, ClassFileEntry[] nested)

  • Method Details

    • getByteCode

      public static ByteCode getByteCode(int opcode)

    • applyByteCodeTargetFixup

      public void applyByteCodeTargetFixup(CodeAttribute codeAttribute)
      Some ByteCodes (in particular, those with labels need to be fixed up after all the bytecodes in the CodeAttribute have been added. (This can't be done beforehand because the CodeAttribute needs to be complete before targets can be assigned.)
      Parameters:
      codeAttribute - the code attribute

    • doWrite

      protected void doWrite(DataOutputStream dos) throws IOException
      Specified by:
      doWrite in class ClassFileEntry
      Throws:
      IOException

    • equals

      public boolean equals(Object obj)
      Specified by:
      equals in class ClassFileEntry

    • extractOperands

      public void extractOperands(OperandManager operandManager, Segment segment, int codeLength)

    • getByteCodeForm

      protected ByteCodeForm getByteCodeForm()

    • getByteCodeIndex

      public int getByteCodeIndex()

    • getByteCodeTargets

      public int[] getByteCodeTargets()

    • getLength

      public int getLength()

    • getName

      public String getName()

    • getNestedClassFileEntries

      public ClassFileEntry[] getNestedClassFileEntries()
      Overrides:
      getNestedClassFileEntries in class ClassFileEntry

    • getNestedPosition

      public int[] getNestedPosition(int index)

    • getNestedPositions

      public int[][] getNestedPositions()

    • getOpcode

      public int getOpcode()

    • getRewrite

      public int[] getRewrite()
      Some bytecodes (the ones with variable lengths) can't have a static rewrite array - they need the ability to update the array. This method permits their associated bytecode formst to query their rewrite array. Note that this should not be called from bytecodes which have a static rewrite; use the table in ByteCodeForm instead to specify those rewrites.
      Returns:
      Some bytecodes.

    • hashCode

      public int hashCode()
      Specified by:
      hashCode in class ClassFileEntry

    • hasMultipleByteCodes

      public boolean hasMultipleByteCodes()
      This method will answer true if the receiver is a multi-bytecode instruction (such as aload0_putfield_super); otherwise, it will answer false.
      Returns:
      boolean true if multibytecode, false otherwise

    • nestedMustStartClassPool

      public boolean nestedMustStartClassPool()

    • resolve

      protected void resolve(ClassConstantPool pool)
      Description copied from class: ClassFileEntry
      Allows the constant pool entries to resolve their nested entries.
      Overrides:
      resolve in class ClassFileEntry
      Parameters:
      pool - TODO

    • setByteCodeIndex

      public void setByteCodeIndex(int byteCodeOffset)
      ByteCodes may need to know their position in the code array (in particular, label byte codes need to know where they are in order to calculate their targets). This method lets the CodeAttribute specify where the byte code is. Since there are no aload0+label instructions, this method doesn't worry about multioperation bytecodes.
      Parameters:
      byteCodeOffset - int position in code array.

    • setByteCodeTargets

      public void setByteCodeTargets(int[] byteCodeTargets)
      Some ByteCodes (in particular, those with labels) have to keep track of byteCodeTargets. These are initially offsets in the CodeAttribute array relative to the byteCodeOffset, but later get fixed up to point to the absolute position in the CodeAttribute array. This method sets the targets.
      Parameters:
      byteCodeTargets - int index in array

    • setNested

      public void setNested(ClassFileEntry[] nested)

    • setNestedPositions

      public void setNestedPositions(int[][] nestedPositions)
      nestedPositions is an array of arrays of ints. Each subarray specifies a position of a nested element (from the nested[] array) and the length of that element. For instance, one might have a nested of: {CPClass java/lang/Foo, CPFloat 3.14} The nestedPositions would then be: {{0,2},{2,2}} In other words, when the bytecode is resolved, the CPClass will be resolved to an int and inserted at position 0 and 1 of the rewrite arguments (the first occurrences of -1). The CPFloat will be resolved to an int position and inserted at positions 2 and 3 of the rewrite arguments.
      Parameters:
      nestedPositions - Each subarray specifies a position of a nested element (from the nested[] array) and the length of that element.

    • setOperand2Bytes

      public void setOperand2Bytes(int operand, int position)
      Given an int operand, set the rewrite bytes for that position and the one immediately following it to a high-byte, low-byte encoding of the operand.
      Parameters:
      operand - int to set the rewrite bytes to
      position - int position in the operands of the rewrite bytes. For a rewrite array of {100, -1, -1, -1} position 0 is the first -1, position 1 is the second -1, etc.

    • setOperandByte

      public void setOperandByte(int operand, int position)
      Given an int operand, treat it as a byte and set the rewrite byte for that position to that value. Mask of anything beyond 0xFF.
      Parameters:
      operand - int to set the rewrite byte to (unsigned)
      position - int position in the operands of the rewrite bytes. For a rewrite array of {100, -1, -1, -1} position 0 is the first -1, position 1 is the second -1, etc.

    • setOperandBytes

      public void setOperandBytes(int[] operands)
      Given an array of ints which correspond to bytes in the operand of the bytecode, set the rewrite bytes of the operand to be the appropriate values. All values in operands[] will be masked with 0xFF so they fit into a byte.
      Parameters:
      operands - int[] rewrite operand bytes

    • setOperandSigned2Bytes

      public void setOperandSigned2Bytes(int operand, int position)
      This is just like setOperandInt, but takes special care when the operand is less than 0 to make sure it's written correctly.
      Parameters:
      operand - int to set the rewrite bytes to
      position - int position of the operands in the rewrite bytes

    • setRewrite

      public void setRewrite(int[] rewrite)
      Some bytecodes (the ones with variable lengths) can't have a static rewrite array - they need the ability to update the array. This method permits that. Note that this should not be called from bytecodes which have a static rewrite; use the table in ByteCodeForm instead to specify those rewrites.
      Parameters:
      rewrite - Some bytecodes.

    • toString

      public String toString()
      Specified by:
      toString in class ClassFileEntry