Class SeekableStreamAdapter

java.lang.Object
java.io.InputStream
org.apache.xmlgraphics.image.codec.util.SeekableStream
org.apache.xmlgraphics.image.loader.util.SeekableStreamAdapter
All Implemented Interfaces:
Closeable, DataInput, AutoCloseable

public class SeekableStreamAdapter extends SeekableStream
Adapter which provides a SeekableStream interface over an ImageInputStream.
  • Constructor Details

    • SeekableStreamAdapter

      public SeekableStreamAdapter(ImageInputStream iin)
      Main constructor
      Parameters:
      iin - the ImageInputStream to operate on
  • Method Details

    • getFilePointer

      public long getFilePointer() throws IOException
      Returns the current offset in this stream.
      Specified by:
      getFilePointer in class SeekableStream
      Returns:
      the offset from the beginning of the stream, in bytes, at which the next read occurs.
      Throws:
      IOException - if an I/O error occurs.
    • read

      public int read() throws IOException
      Reads the next byte of data from the input stream. The value byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been reached, the value -1 is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

      A subclass must provide an implementation of this method.

      Specified by:
      read in class SeekableStream
      Returns:
      the next byte of data, or -1 if the end of the stream is reached.
      Throws:
      IOException - if an I/O error occurs.
    • read

      public int read(byte[] b, int off, int len) throws IOException
      Reads up to len bytes of data from the input stream into an array of bytes. An attempt is made to read as many as len bytes, but a smaller number may be read, possibly zero. The number of bytes actually read is returned as an integer.

      This method blocks until input data is available, end of stream is detected, or an exception is thrown.

      If b is null, a NullPointerException is thrown.

      If off is negative, or len is negative, or off+len is greater than the length of the array b, then an IndexOutOfBoundsException is thrown.

      If len is zero, then no bytes are read and 0 is returned; otherwise, there is an attempt to read at least one byte. If no byte is available because the stream is at end of stream, the value -1 is returned; otherwise, at least one byte is read and stored into b.

      The first byte read is stored into element b[off], the next one into b[off+1], and so on. The number of bytes read is, at most, equal to len. Let k be the number of bytes actually read; these bytes will be stored in elements b[off] through b[off+k-1], leaving elements b[off+k] through b[off+len-1] unaffected.

      In every case, elements b[0] through b[off] and elements b[off+len] through b[b.length-1] are unaffected.

      If the first byte cannot be read for any reason other than end of stream, then an IOException is thrown. In particular, an IOException is thrown if the input stream has been closed.

      A subclass must provide an implementation of this method.

      Specified by:
      read in class SeekableStream
      Parameters:
      b - the buffer into which the data is read.
      off - the start offset in array b 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.
      Throws:
      IOException - if an I/O error occurs.
    • seek

      public void seek(long pos) throws IOException
      Sets the offset, measured from the beginning of this stream, at which the next read occurs.

      If canSeekBackwards() returns false, then setting pos to an offset smaller than the current value of getFilePointer() will have no effect.

      Specified by:
      seek in class SeekableStream
      Parameters:
      pos - the offset position, measured in bytes from the beginning of the stream, at which to set the stream pointer.
      Throws:
      IOException - if pos is less than 0 or if an I/O error occurs.
    • canSeekBackwards

      public boolean canSeekBackwards()
      Returns true if this object supports calls to seek(pos) with an offset pos smaller than the current offset, as returned by getFilePointer.
      Overrides:
      canSeekBackwards in class SeekableStream
    • skipBytes

      public int skipBytes(int n) throws IOException
      Attempts to skip over n bytes of input discarding the skipped bytes.

      This method may skip over some smaller number of bytes, possibly zero. This may result from any of a number of conditions; reaching end of stream before n bytes have been skipped is only one possibility. This method never throws an EOFException. The actual number of bytes skipped is returned. If n is negative, no bytes are skipped.

      Specified by:
      skipBytes in interface DataInput
      Overrides:
      skipBytes in class SeekableStream
      Parameters:
      n - the number of bytes to be skipped.
      Returns:
      the actual number of bytes skipped.
      Throws:
      IOException - if an I/O error occurs.