Class BufferedRandomInput

java.lang.Object
uk.ac.starlink.fits.BufferedRandomInput
All Implemented Interfaces:
BasicInput
public class BufferedRandomInput extends Object implements BasicInput
BasicInput implementation based on a RandomAccessFile. Buffering of the underlying file is performed on the assumption that access will be largely sequential.
Since:
8 Nov 2017
Author:
Mark Taylor

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final int
    DFLT_BUFSIZE
     

  • Constructor Summary

    Constructors
    Constructor
    Description
    BufferedRandomInput(RandomAccessFile file, long offset0)
    Constructs a BufferedRandomInput with a default sized buffer.
    BufferedRandomInput(RandomAccessFile file, long offset0, int bufsize)
    Constructs a BufferedRandomInput with a buffer of specified size.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    close()
    Releases resources belonging to this object.
    long
    getOffset()
    Returns the curent position in this stream (optional operation).
    boolean
    isRandom()
    Indicates whether this object supports random access.
    byte
    readByte()
    Reads a byte from the stream.
    void
    readBytes(byte[] bbuf)
    Reads bytes into an array from the stream.
    double
    readDouble()
    Reads an 8-byte floating point value from the stream.
    float
    readFloat()
    Reads a 4-byte floating point value from the stream.
    int
    readInt()
    Reads a 4-byte integer from the stream.
    long
    readLong()
    Reads an 8-byte integer from the stream.
    short
    readShort()
    Reads a 2-byte integer from the stream.
    void
    seek(long offset)
    Moves the current position of this stream to a given byte offset (optional operation).
    void
    skip(long nbytes)
    Skips a given number of bytes forwards through the stream.

    Methods inherited from class Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

    • DFLT_BUFSIZE

      public static final int DFLT_BUFSIZE

  • Constructor Details

    • BufferedRandomInput

      public BufferedRandomInput(RandomAccessFile file, long offset0) throws IOException
      Constructs a BufferedRandomInput with a default sized buffer.
      Parameters:
      file - file
      offset0 - offset into file of stream start
      Throws:
      IOException

    • BufferedRandomInput

      public BufferedRandomInput(RandomAccessFile file, long offset0, int bufsize) throws IOException
      Constructs a BufferedRandomInput with a buffer of specified size.
      Parameters:
      file - file
      offset0 - offset into file of stream start
      bufsize - buffer size
      Throws:
      IOException

  • Method Details

    • readByte

      public byte readByte() throws IOException
      Description copied from interface: BasicInput
      Reads a byte from the stream. The current position is advanced.
      Specified by:
      readByte in interface BasicInput
      Returns:
      byte value
      Throws:
      IOException

    • readShort

      public short readShort() throws IOException
      Description copied from interface: BasicInput
      Reads a 2-byte integer from the stream. The current position is advanced.
      Specified by:
      readShort in interface BasicInput
      Returns:
      short value
      Throws:
      IOException

    • readInt

      public int readInt() throws IOException
      Description copied from interface: BasicInput
      Reads a 4-byte integer from the stream. The current position is advanced.
      Specified by:
      readInt in interface BasicInput
      Returns:
      int value
      Throws:
      IOException

    • readLong

      public long readLong() throws IOException
      Description copied from interface: BasicInput
      Reads an 8-byte integer from the stream. The current position is advanced.
      Specified by:
      readLong in interface BasicInput
      Returns:
      long value
      Throws:
      IOException

    • readFloat

      public float readFloat() throws IOException
      Description copied from interface: BasicInput
      Reads a 4-byte floating point value from the stream. The current position is advanced.
      Specified by:
      readFloat in interface BasicInput
      Returns:
      float value
      Throws:
      IOException

    • readDouble

      public double readDouble() throws IOException
      Description copied from interface: BasicInput
      Reads an 8-byte floating point value from the stream. The current position is advanced.
      Specified by:
      readDouble in interface BasicInput
      Returns:
      double value
      Throws:
      IOException

    • readBytes

      public void readBytes(byte[] bbuf) throws IOException
      Description copied from interface: BasicInput
      Reads bytes into an array from the stream. The current position is advanced.
      Specified by:
      readBytes in interface BasicInput
      Parameters:
      bbuf - array into which the bytes are read; the number of bytes read is the length of the array
      Throws:
      IOException

    • isRandom

      public boolean isRandom()
      Description copied from interface: BasicInput
      Indicates whether this object supports random access. The seek and getOffset methods may only be called if this method returns true.
      Specified by:
      isRandom in interface BasicInput
      Returns:
      true iff random access is supported

    • skip

      public void skip(long nbytes) throws IOException
      Description copied from interface: BasicInput
      Skips a given number of bytes forwards through the stream. An exception is thrown if there are not enough bytes left.
      Specified by:
      skip in interface BasicInput
      Parameters:
      nbytes - number of bytes to skip
      Throws:
      IOException

    • getOffset

      public long getOffset()
      Description copied from interface: BasicInput
      Returns the curent position in this stream (optional operation).
      Specified by:
      getOffset in interface BasicInput

    • seek

      public void seek(long offset) throws IOException
      Description copied from interface: BasicInput
      Moves the current position of this stream to a given byte offset (optional operation).
      Specified by:
      seek in interface BasicInput
      Throws:
      IOException

    • close

      public void close() throws IOException
      Description copied from interface: BasicInput
      Releases resources belonging to this object. Attempts to use it after a call to this method result in undefined behaviour.
      Specified by:
      close in interface BasicInput
      Throws:
      IOException

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