Package org.apache.pdfbox.io

Class RandomAccessBufferedFileInputStream

java.lang.Object
java.io.InputStream
org.apache.pdfbox.io.RandomAccessBufferedFileInputStream
All Implemented Interfaces:
Closeable, AutoCloseable, RandomAccessRead
public class RandomAccessBufferedFileInputStream extends InputStream implements RandomAccessRead
Provides InputStream access to portions of a file combined with buffered reading of content. Start of next bytes to read can be set via seek method. File is accessed via RandomAccessFile and is read in byte chunks which are cached.

  • Field Details

    • TMP_FILE_PREFIX

      private static final String TMP_FILE_PREFIX
      The prefix for the temp file being used.
      See Also:

    • pageSizeShift

      private int pageSizeShift

    • pageSize

      private int pageSize

    • pageOffsetMask

      private long pageOffsetMask

    • maxCachedPages

      private int maxCachedPages

    • tempFile

      private File tempFile

    • lastRemovedCachePage

      private byte[] lastRemovedCachePage

    • pageCache

      private final Map<Long,byte[]> pageCache
      Create a LRU page cache.

    • curPageOffset

      private long curPageOffset

    • curPage

      private byte[] curPage

    • offsetWithinPage

      private int offsetWithinPage

    • raFile

      private final RandomAccessFile raFile

    • fileLength

      private final long fileLength

    • fileOffset

      private long fileOffset

    • isClosed

      private boolean isClosed

  • Constructor Details

    • RandomAccessBufferedFileInputStream

      public RandomAccessBufferedFileInputStream(String filename) throws IOException
      Create a random access input stream instance for the file with the given name.
      Parameters:
      filename - the filename of the file to be read.
      Throws:
      IOException - if something went wrong while accessing the given file.

    • RandomAccessBufferedFileInputStream

      public RandomAccessBufferedFileInputStream(File file) throws IOException
      Create a random access input stream instance for the given file.
      Parameters:
      file - the file to be read.
      Throws:
      IOException - if something went wrong while accessing the given file.

    • RandomAccessBufferedFileInputStream

      public RandomAccessBufferedFileInputStream(InputStream input) throws IOException
      Create a random access input stream for the given input stream by copying the data to a temporary file.
      Parameters:
      input - the input stream to be read. It will be closed by this method.
      Throws:
      IOException - if something went wrong while creating the temporary file.

  • Method Details

    • createTmpFile

      private File createTmpFile(InputStream input) throws IOException
      Throws:
      IOException

    • deleteTempFile

      private void deleteTempFile()
      Remove the temporary file. A temporary file is created if this class is instantiated with an InputStream

    • getPosition

      public long getPosition()
      Returns offset in file at which next byte would be read.
      Specified by:
      getPosition in interface RandomAccessRead
      Returns:
      offset of next byte which will be returned with next RandomAccessRead.read() (if no more bytes are left it returns a value >= length of source)

    • seek

      public void seek(long newOffset) throws IOException
      Seeks to new position. If new position is outside of current page the new page is either taken from cache or read from file and added to cache.
      Specified by:
      seek in interface RandomAccessRead
      Parameters:
      newOffset - the position to seek to.
      Throws:
      IOException - if something went wrong.

    • readPage

      private byte[] readPage() throws IOException
      Reads a page with data from current file position. If we have a previously removed page from cache the buffer of this page is reused. Otherwise a new byte buffer is created.
      Throws:
      IOException

    • read

      public int read() throws IOException
      Description copied from interface: RandomAccessRead
      Read a single byte of data.
      Specified by:
      read in interface RandomAccessRead
      Specified by:
      read in class InputStream
      Returns:
      The byte of data that is being read.
      Throws:
      IOException - If there is an error while reading the data.

    • read

      public int read(byte[] b) throws IOException
      Description copied from interface: RandomAccessRead
      Read a buffer of data.
      Specified by:
      read in interface RandomAccessRead
      Overrides:
      read in class InputStream
      Parameters:
      b - The buffer to write the data to.
      Returns:
      The number of bytes that were actually read.
      Throws:
      IOException - If there was an error while reading the data.

    • read

      public int read(byte[] b, int off, int len) throws IOException
      Description copied from interface: RandomAccessRead
      Read a buffer of data.
      Specified by:
      read in interface RandomAccessRead
      Overrides:
      read in class InputStream
      Parameters:
      b - The buffer to write the data to.
      off - Offset into the buffer to start writing.
      len - The amount of data to attempt to read.
      Returns:
      The number of bytes that were actually read.
      Throws:
      IOException - If there was an error while reading the data.

    • available

      public int available() throws IOException
      Description copied from interface: RandomAccessRead
      Returns an estimate of the number of bytes that can be read.
      Specified by:
      available in interface RandomAccessRead
      Overrides:
      available in class InputStream
      Returns:
      the number of bytes that can be read
      Throws:
      IOException - if this random access has been closed

    • skip

      public long skip(long n) throws IOException
      Overrides:
      skip in class InputStream
      Throws:
      IOException

    • length

      public long length() throws IOException
      Description copied from interface: RandomAccessRead
      The total number of bytes that are available.
      Specified by:
      length in interface RandomAccessRead
      Returns:
      The number of bytes available.
      Throws:
      IOException - If there is an IO error while determining the length of the data stream.

    • close

      public void close() throws IOException
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Overrides:
      close in class InputStream
      Throws:
      IOException

    • isClosed

      public boolean isClosed()
      Description copied from interface: RandomAccessRead
      Returns true if this stream has been closed.
      Specified by:
      isClosed in interface RandomAccessRead

    • peek

      public int peek() throws IOException
      Description copied from interface: RandomAccessRead
      This will peek at the next byte.
      Specified by:
      peek in interface RandomAccessRead
      Returns:
      The next byte on the stream, leaving it as available to read.
      Throws:
      IOException - If there is an error reading the next byte.

    • rewind

      public void rewind(int bytes) throws IOException
      Description copied from interface: RandomAccessRead
      Seek backwards the given number of bytes.
      Specified by:
      rewind in interface RandomAccessRead
      Parameters:
      bytes - the number of bytes to be seeked backwards
      Throws:
      IOException - If there is an error while seeking

    • readFully

      public byte[] readFully(int length) throws IOException
      Description copied from interface: RandomAccessRead
      Reads a given number of bytes.
      Specified by:
      readFully in interface RandomAccessRead
      Parameters:
      length - the number of bytes to be read
      Returns:
      a byte array containing the bytes just read
      Throws:
      IOException - if an I/O error occurs while reading data

    • isEOF

      public boolean isEOF() throws IOException
      Description copied from interface: RandomAccessRead
      A simple test to see if we are at the end of the data.
      Specified by:
      isEOF in interface RandomAccessRead
      Returns:
      true if we are at the end of the data.
      Throws:
      IOException - If there is an error reading the next byte.