Package org.apache.pdfbox.io

Class ByteArrayPushBackInputStream

java.lang.Object
java.io.InputStream
java.io.FilterInputStream
java.io.PushbackInputStream
org.apache.pdfbox.io.PushBackInputStream
org.apache.pdfbox.io.ByteArrayPushBackInputStream
All Implemented Interfaces:
Closeable, AutoCloseable
public class ByteArrayPushBackInputStream extends PushBackInputStream
PushBackInputStream for byte arrays. The inheritance from PushBackInputStream is only to avoid the introduction of an interface with all PushBackInputStream methods. The parent PushBackInputStream is not used in any way and all methods are overridden. (Thus when adding new methods to PushBackInputStream override them in this class as well!) unread() is limited to the number of bytes already read from this stream (i.e. the current position in the array). This limitation usually poses no problem to a parser, but allows for some optimization since only one array has to be dealt with. Note: This class is not thread safe. Clients must provide synchronization if needed. Note: Calling unread() after mark() will cause (part of) the unread data to be read again after reset(). Thus do not call unread() between mark() and reset().
Version:
$Revision: 1.2 $
Author:
Andreas Weiss (andreas.weiss@switzerland.org)

  • Constructor Details

    • ByteArrayPushBackInputStream

      public ByteArrayPushBackInputStream(byte[] input) throws IOException
      Constructor.
      Parameters:
      input - Data to read from. Note that calls to unread() will modify this array! If this is not desired, pass a copy.
      Throws:
      IOException - If there is an IO error.

  • Method Details

    • peek

      public int peek()
      This will peek at the next byte.
      Overrides:
      peek in class PushBackInputStream
      Returns:
      The next byte on the stream, leaving it as available to read.

    • isEOF

      public boolean isEOF()
      A simple test to see if we are at the end of the stream.
      Overrides:
      isEOF in class PushBackInputStream
      Returns:
      true if we are at the end of the stream.

    • mark

      public void mark(int readlimit)
      Save the state of this stream.
      Overrides:
      mark in class PushbackInputStream
      Parameters:
      readlimit - Has no effect.
      See Also:

    • markSupported

      public boolean markSupported()
      Check if mark is supported.
      Overrides:
      markSupported in class PushbackInputStream
      Returns:
      Always true.
      See Also:

    • reset

      public void reset()
      Restore the state of this stream to the last saveState call.
      Overrides:
      reset in class PushbackInputStream
      See Also:

    • available

      public int available()
      Available bytes.
      Overrides:
      available in class PushbackInputStream
      Returns:
      Available bytes.
      See Also:

    • size

      public int size()
      Totally available bytes in the underlying array.
      Returns:
      Available bytes.

    • unread

      public void unread(int by) throws IOException
      Pushes back a byte. After this method returns, the next byte to be read will have the value (byte)by.
      Overrides:
      unread in class PushBackInputStream
      Parameters:
      by - the int value whose low-order byte is to be pushed back.
      Throws:
      IOException - - If there is not enough room in the buffer for the byte.
      See Also:

    • unread

      public void unread(byte[] buffer, int off, int len) throws IOException
      Pushes back a portion of an array of bytes by copying it to the front of the pushback buffer. After this method returns, the next byte to be read will have the value b[off], the byte after that will have the value b[off+1], and so forth.
      Overrides:
      unread in class PushBackInputStream
      Parameters:
      buffer - the byte array to push back.
      off - the start offset of the data.
      len - the number of bytes to push back.
      Throws:
      IOException - If there is not enough room in the pushback buffer for the specified number of bytes.
      See Also:

    • unread

      public void unread(byte[] buffer) throws IOException
      Pushes back a portion of an array of bytes by copying it to the front of the pushback buffer. After this method returns, the next byte to be read will have the value buffer[0], the byte after that will have the value buffer[1], and so forth.
      Overrides:
      unread in class PushBackInputStream
      Parameters:
      buffer - the byte array to push back.
      Throws:
      IOException - If there is not enough room in the pushback buffer for the specified number of bytes.
      See Also:

    • read

      public int read()
      Read a byte.
      Overrides:
      read in class PushBackInputStream
      Returns:
      Byte read or -1 if no more bytes are available.
      See Also:

    • read

      public int read(byte[] buffer)
      Read a number of bytes.
      Overrides:
      read in class PushBackInputStream
      Parameters:
      buffer - the buffer into which the data is read.
      Returns:
      the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.
      See Also:

    • read

      public int read(byte[] buffer, int off, int len)
      Read a number of bytes.
      Overrides:
      read in class PushBackInputStream
      Parameters:
      buffer - the buffer into which the data is read.
      off - the start offset in array buffer at which the data is written.
      len - the maximum number of bytes to read.
      Returns:
      the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.
      See Also:

    • localRead

      public int localRead(byte[] buffer, int off, int len)
      Read a number of bytes. Internal method that assumes off and len to be valid.
      Parameters:
      buffer - the buffer into which the data is read.
      off - the start offset in array buffer at which the data is written.
      len - the maximum number of bytes to read.
      Returns:
      the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.
      See Also:

    • skip

      public long skip(long num)
      Skips over and discards n bytes of data from this input stream. The skip method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly 0. This may result from any of a number of conditions; reaching end of file before n bytes have been skipped is only one possibility. The actual number of bytes skipped is returned. If n is negative, no bytes are skipped.
      Overrides:
      skip in class PushbackInputStream
      Parameters:
      num - the number of bytes to be skipped.
      Returns:
      the actual number of bytes skipped.
      See Also:

    • seek

      public int seek(int newpos)
      Position the stream at a given index. Positioning the stream at position size() will cause the next call to read() to return -1.
      Parameters:
      newpos - Position in the underlying array. A negative value will be interpreted as 0, a value greater than size() as size().
      Returns:
      old position.