Package org.apache.commons.compress.archivers.zip

Class ResourceAlignmentExtraField

java.lang.Object
org.apache.commons.compress.archivers.zip.ResourceAlignmentExtraField
All Implemented Interfaces:
ZipExtraField
public class ResourceAlignmentExtraField extends Object implements ZipExtraField
An extra field who's sole purpose is to align and pad the local file header so that the entry's data starts at a certain position.

The padding content of the padding is ignored and not retained when reading a padding field.

This enables Commons Compress to create "aligned" archives similar to Android's zipalign command line tool.

Since:
1.14
See Also:

  • Field Details

    • MAX_ALIGNMENT

      private static final int MAX_ALIGNMENT
      See Also:

    • ID

      public static final ZipShort ID
      Extra field id used for storing alignment and padding.

    • BASE_SIZE

      public static final int BASE_SIZE
      Base field size.
      See Also:

    • ALLOW_METHOD_MESSAGE_CHANGE_FLAG

      private static final int ALLOW_METHOD_MESSAGE_CHANGE_FLAG
      See Also:

    • alignment

      private short alignment

    • allowMethodChange

      private boolean allowMethodChange

    • padding

      private int padding

  • Constructor Details

    • ResourceAlignmentExtraField

      public ResourceAlignmentExtraField()
      Constructs a new instance.

    • ResourceAlignmentExtraField

      public ResourceAlignmentExtraField(int alignment)
      Constructs a new instance.
      Parameters:
      alignment - A positive alignment less than Short.MAX_VALUE.

    • ResourceAlignmentExtraField

      public ResourceAlignmentExtraField(int alignment, boolean allowMethodChange)
      Constructs a new instance.
      Parameters:
      alignment - A positive alignment less than Short.MAX_VALUE.
      allowMethodChange - whether a method change is allowed when re-compressing the ZIP file.

    • ResourceAlignmentExtraField

      public ResourceAlignmentExtraField(int alignment, boolean allowMethodChange, int padding)
      Constructs a new instance.
      Parameters:
      alignment - A positive alignment less than Short.MAX_VALUE.
      allowMethodChange - whether a method change is allowed when re-compressing the ZIP file.
      padding - padding.

  • Method Details

    • allowMethodChange

      public boolean allowMethodChange()
      Indicates whether a method change is allowed when re-compressing the ZIP file.
      Returns:
      true if a method change is allowed, false otherwise.

    • getAlignment

      public short getAlignment()
      Gets requested alignment.
      Returns:
      requested alignment.

    • getCentralDirectoryData

      public byte[] getCentralDirectoryData()
      Description copied from interface: ZipExtraField
      The actual data to put into central directory - without Header-ID or length specifier.
      Specified by:
      getCentralDirectoryData in interface ZipExtraField
      Returns:
      the data

    • getCentralDirectoryLength

      public ZipShort getCentralDirectoryLength()
      Description copied from interface: ZipExtraField
      Length of the extra field in the central directory - without Header-ID or length specifier.
      Specified by:
      getCentralDirectoryLength in interface ZipExtraField
      Returns:
      the length of the field in the central directory

    • getHeaderId

      public ZipShort getHeaderId()
      Description copied from interface: ZipExtraField
      The Header-ID.
      Specified by:
      getHeaderId in interface ZipExtraField
      Returns:
      The HeaderId value

    • getLocalFileDataData

      public byte[] getLocalFileDataData()
      Description copied from interface: ZipExtraField
      The actual data to put into local file data - without Header-ID or length specifier.
      Specified by:
      getLocalFileDataData in interface ZipExtraField
      Returns:
      the data

    • getLocalFileDataLength

      public ZipShort getLocalFileDataLength()
      Description copied from interface: ZipExtraField
      Length of the extra field in the local file data - without Header-ID or length specifier.
      Specified by:
      getLocalFileDataLength in interface ZipExtraField
      Returns:
      the length of the field in the local file data

    • parseFromCentralDirectoryData

      public void parseFromCentralDirectoryData(byte[] buffer, int offset, int length) throws ZipException
      Description copied from interface: ZipExtraField
      Populate data from this array as if it was in central directory data.
      Specified by:
      parseFromCentralDirectoryData in interface ZipExtraField
      Parameters:
      buffer - the buffer to read data from
      offset - offset into buffer to read data
      length - the length of data
      Throws:
      ZipException - on error

    • parseFromLocalFileData

      public void parseFromLocalFileData(byte[] buffer, int offset, int length) throws ZipException
      Description copied from interface: ZipExtraField
      Populate data from this array as if it was in local file data.
      Specified by:
      parseFromLocalFileData in interface ZipExtraField
      Parameters:
      buffer - the buffer to read data from
      offset - offset into buffer to read data
      length - the length of data
      Throws:
      ZipException - on error