Interface ImagePointer

All Known Implementing Classes:
CorruptImagePointer, ImagePointer, J9DDRImagePointer, JCImagePointer

public interface ImagePointer
Represents an address in memory. To create an ImagePointer using an absolute address use com.ibm.dtfj.image.ImageAddressSpace.getPointer()
See Also:
  • Method Summary

    Modifier and Type
    Method
    Description
    add(long offset)
    Build a new image pointer offset from this one by the given amount.
    boolean
    Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
    long
    Get the unwrapped address, represented as a Java long.
    Get the address space to which this pointer belongs.
    byte
    getByteAt(long index)
    Get the value at the given offset from this pointer.
    double
    getDoubleAt(long index)
    Get the value at the given offset from this pointer.
    float
    getFloatAt(long index)
    Get the value at the given offset from this pointer.
    int
    getIntAt(long index)
    Get the value at the given offset from this pointer.
    long
    getLongAt(long index)
    Get the value at the given offset from this pointer.
    getPointerAt(long index)
    Get the value at the given offset from this pointer.
    Get the OS-specific properties for this address
    short
    getShortAt(long index)
    Get the value at the given offset from this pointer.
    int
    Answers an integer hash code for the receiver.
    boolean
    Tests memory execute permission.
    boolean
    Tests memory read/write permission.
    boolean
    Tests memory shared permission.
  • Method Details

    • getAddress

      long getAddress()

      Get the unwrapped address, represented as a Java long.

      Use caution when comparing addresses, as some addresses may be negative.

      Note that, on segmented memory architectures, it may not be possible to represent all addresses accurately as integers.

      Returns:
      the unwrapped address, represented as a 64-bit integer.
    • getAddressSpace

      ImageAddressSpace getAddressSpace()
      Get the address space to which this pointer belongs.
      Returns:
      the address space to which this pointer belongs.
    • add

      ImagePointer add(long offset)
      Build a new image pointer offset from this one by the given amount.
      Parameters:
      offset - Offset in bytes.
      Returns:
      a new ImagePointer based at getAddress() + offset
    • isExecutable

      boolean isExecutable() throws DataUnavailable
      Tests memory execute permission.
      Returns:
      true if this memory address is within an executable page.
      Throws:
      DataUnavailable
    • isReadOnly

      boolean isReadOnly() throws DataUnavailable
      Tests memory read/write permission.
      Returns:
      true if this memory address is read-only. False otherwise.
      Throws:
      DataUnavailable
    • isShared

      boolean isShared() throws DataUnavailable
      Tests memory shared permission.
      Returns:
      true if this memory address is shared between processes.
      Throws:
      DataUnavailable
    • getPointerAt

      ImagePointer getPointerAt(long index) throws MemoryAccessException, CorruptDataException
      Get the value at the given offset from this pointer. To determine the number of bytes to skip after this call to read the next value, use ImageProcess.getPointerSize(). Note: to create an ImagePointer using an absolute address use com.ibm.dtfj.image.ImageAddressSpace.getPointer()
      Parameters:
      index - an offset (in bytes) from the current position
      Returns:
      the 32 or 64-bit pointer stored at getAddress() + index
      Throws:
      MemoryAccessException - if the memory cannot be read
      CorruptDataException - if the memory should be in the image, but is missing or corrupted
      See Also:
    • getLongAt

      long getLongAt(long index) throws MemoryAccessException, CorruptDataException
      Get the value at the given offset from this pointer.
      Parameters:
      index - an offset (in bytes) from the current position
      Returns:
      the 64-bit long stored at getAddress() + index
      Throws:
      MemoryAccessException - if the memory cannot be read
      CorruptDataException - if the memory should be in the image, but is missing or corrupted
    • getIntAt

      int getIntAt(long index) throws MemoryAccessException, CorruptDataException
      Get the value at the given offset from this pointer.
      Parameters:
      index - an offset (in bytes) from the current position
      Returns:
      the 32-bit int stored at getAddress() + index
      Throws:
      MemoryAccessException - if the memory cannot be read
      CorruptDataException - if the memory should be in the image, but is missing or corrupted
    • getShortAt

      short getShortAt(long index) throws MemoryAccessException, CorruptDataException
      Get the value at the given offset from this pointer.
      Parameters:
      index - an offset (in bytes) from the current position
      Returns:
      the 16-bit short stored at getAddress() + index
      Throws:
      MemoryAccessException - if the memory cannot be read
      CorruptDataException - if the memory should be in the image, but is missing or corrupted
    • getByteAt

      byte getByteAt(long index) throws MemoryAccessException, CorruptDataException
      Get the value at the given offset from this pointer.
      Parameters:
      index - an offset (in bytes) from the current position
      Returns:
      the 8-bit byte stored at getAddress() + index
      Throws:
      MemoryAccessException - if the memory cannot be read
      CorruptDataException - if the memory should be in the image, but is missing or corrupted
    • getFloatAt

      float getFloatAt(long index) throws MemoryAccessException, CorruptDataException
      Get the value at the given offset from this pointer.
      Parameters:
      index - an offset (in bytes) from the current position
      Returns:
      the 32-bit float stored at getAddress() + index
      Throws:
      MemoryAccessException - if the memory cannot be read
      CorruptDataException - if the memory should be in the image, but is missing or corrupted
    • getDoubleAt

      double getDoubleAt(long index) throws MemoryAccessException, CorruptDataException
      Get the value at the given offset from this pointer.
      Parameters:
      index - an offset (in bytes) from the current position
      Returns:
      the 64-bit double stored at getAddress() + index
      Throws:
      MemoryAccessException - if the memory cannot be read
      CorruptDataException - if the memory should be in the image, but is missing or corrupted
    • equals

      boolean equals(Object obj)
      Description copied from class: java.lang.Object
      Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison. The implementation in Object answers true only if the argument is the exact same object as the receiver (==).
      Overrides:
      equals in class Object
      Parameters:
      obj -
      Returns:
      True obj refers to the same Image Pointer in the image
      See Also:
    • hashCode

      int hashCode()
      Description copied from class: java.lang.Object
      Answers an integer hash code for the receiver. Any two objects which answer true when passed to .equals must answer the same value for this method.
      Overrides:
      hashCode in class Object
      Returns:
      the receiver's hash.
      See Also:
    • getProperties

      Properties getProperties()
      Get the OS-specific properties for this address
      Returns:
      a table of OS-specific properties for this address. Values which are commonly available include
      • "readable" -- whether the memory address can be read from
      • "writable" -- whether the memory address can be written to
      • "executable" -- whether data in the memory address can be executed
      Since:
      1.11