Package org.docx4j.org.apache.poi.poifs.storage

Class BATBlock

java.lang.Object
org.docx4j.org.apache.poi.poifs.storage.BATBlock
All Implemented Interfaces:
BlockWritable
public final class BATBlock extends Object
A block of block allocation table entries. BATBlocks are created only through a static factory method: createBATBlocks.

  • Field Details

  • Method Details

    • createBATBlock

      public static BATBlock createBATBlock(POIFSBigBlockSize bigBlockSize, ByteBuffer data)
      Create a single BATBlock from the byte buffer, which must hold at least one big block of data to be read.

    • createEmptyBATBlock

      public static BATBlock createEmptyBATBlock(POIFSBigBlockSize bigBlockSize, boolean isXBAT)
      Creates a single BATBlock, with all the values set to empty.

    • createBATBlocks

      public static BATBlock[] createBATBlocks(POIFSBigBlockSize bigBlockSize, int[] entries)
      Create an array of BATBlocks from an array of int block allocation table entries
      Parameters:
      entries - the array of int entries
      Returns:
      the newly created array of BATBlocks

    • createXBATBlocks

      public static BATBlock[] createXBATBlocks(POIFSBigBlockSize bigBlockSize, int[] entries, int startBlock)
      Create an array of XBATBlocks from an array of int block allocation table entries
      Parameters:
      entries - the array of int entries
      startBlock - the start block of the array of XBAT blocks
      Returns:
      the newly created array of BATBlocks

    • calculateStorageRequirements

      public static int calculateStorageRequirements(POIFSBigBlockSize bigBlockSize, int entryCount)
      Calculate how many BATBlocks are needed to hold a specified number of BAT entries.
      Parameters:
      entryCount - the number of entries
      Returns:
      the number of BATBlocks needed

    • calculateXBATStorageRequirements

      public static int calculateXBATStorageRequirements(POIFSBigBlockSize bigBlockSize, int entryCount)
      Calculate how many XBATBlocks are needed to hold a specified number of BAT entries.
      Parameters:
      entryCount - the number of entries
      Returns:
      the number of XBATBlocks needed

    • calculateMaximumSize

      public static long calculateMaximumSize(POIFSBigBlockSize bigBlockSize, int numBATs)
      Calculates the maximum size of a file which is addressable given the number of FAT (BAT) sectors specified. (We don't care if those BAT blocks come from the 109 in the header, or from header + XBATS, it won't affect the calculation) The actual file size will be between [size of fatCount-1 blocks] and [size of fatCount blocks]. For 512 byte block sizes, this means we may over-estimate by up to 65kb. For 4096 byte block sizes, this means we may over-estimate by up to 4mb

    • calculateMaximumSize

      public static long calculateMaximumSize(HeaderBlock header)

    • getBATBlockAndIndex

      public static BATBlock.BATBlockAndIndex getBATBlockAndIndex(int offset, HeaderBlock header, List<BATBlock> bats)
      Returns the BATBlock that handles the specified offset, and the relative index within it. The List of BATBlocks must be in sequential order

    • getSBATBlockAndIndex

      public static BATBlock.BATBlockAndIndex getSBATBlockAndIndex(int offset, HeaderBlock header, List<BATBlock> sbats)
      Returns the BATBlock that handles the specified offset, and the relative index within it, for the mini stream. The List of BATBlocks must be in sequential order

    • hasFreeSectors

      public boolean hasFreeSectors()
      Does this BATBlock have any free sectors in it, or is it full?

    • getUsedSectors

      public int getUsedSectors(boolean isAnXBAT)
      How many sectors in this block are taken? Note that calling hasFreeSectors() is much quicker

    • getValueAt

      public int getValueAt(int relativeOffset)

    • setValueAt

      public void setValueAt(int relativeOffset, int value)

    • setOurBlockIndex

      public void setOurBlockIndex(int index)
      Record where in the file we live

    • getOurBlockIndex

      public int getOurBlockIndex()
      Retrieve where in the file we live

    • doWriteData

      protected void doWriteData(OutputStream stream, byte[] data) throws IOException
      Default implementation of write for extending classes that contain their data in a simple array of bytes.
      Parameters:
      stream - the OutputStream to which the data should be written.
      data - the byte array of to be written.
      Throws:
      IOException - on problems writing to the specified stream.

    • writeBlocks

      public void writeBlocks(OutputStream stream) throws IOException
      Write the storage to an OutputStream
      Specified by:
      writeBlocks in interface BlockWritable
      Parameters:
      stream - the OutputStream to which the stored data should be written
      Throws:
      IOException - on problems writing to the specified stream