Package org.apache.xmlgraphics.image.codec.util

Class ImageInputStreamSeekableStreamAdapter

  • All Implemented Interfaces:
    java.io.Closeable, java.io.DataInput, java.lang.AutoCloseable
    public class ImageInputStreamSeekableStreamAdapter
extends SeekableStream
    A subclass of SeekableStream that may be used to wrap a regular ImageInputStream.

    • Constructor Detail

      • ImageInputStreamSeekableStreamAdapter

        public ImageInputStreamSeekableStreamAdapter​(javax.imageio.stream.ImageInputStream stream)
                                      throws java.io.IOException
        Constructs a SeekableStream that takes its source data from a regular ImageInputStream.
        Parameters:
        stream - the underlying ImageInputStream to use
        Throws:
        java.io.IOException

    • Method Detail

      • 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

      • getFilePointer

        public long getFilePointer()
                    throws java.io.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:
        java.io.IOException - if an I/O error occurs.

      • seek

        public void seek​(long pos)
          throws java.io.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:
        java.io.IOException - if pos is less than 0 or if an I/O error occurs.

      • read

        public int read()
         throws java.io.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:
        java.io.IOException - if an I/O error occurs.

      • read

        public int read​(byte[] b,
                int off,
                int len)
         throws java.io.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:
        java.io.IOException - if an I/O error occurs.

      • close

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