Class VisibleBufferedInputStream

java.lang.Object
java.io.InputStream
org.postgresql.core.VisibleBufferedInputStream
All Implemented Interfaces:
Closeable, AutoCloseable

public class VisibleBufferedInputStream extends InputStream
A faster version of BufferedInputStream. Does no synchronisation and allows direct access to the used byte[] buffer.
  • Field Details

    • MINIMUM_READ

      private static final int MINIMUM_READ
      If a direct read to byte array is called that would require a smaller read from the wrapped stream that MINIMUM_READ then first fill the buffer and serve the bytes from there. Larger reads are directly done to the provided byte array.
      See Also:
    • STRING_SCAN_SPAN

      private static final int STRING_SCAN_SPAN
      In how large spans is the C string zero-byte scanned.
      See Also:
    • wrapped

      private final InputStream wrapped
      The wrapped input stream.
    • buffer

      private byte[] buffer
      The buffer.
    • index

      private int index
      Current read position in the buffer.
    • endIndex

      private int endIndex
      How far is the buffer filled with valid data.
    • timeoutRequested

      private boolean timeoutRequested
      socket timeout has been requested
  • Constructor Details

    • VisibleBufferedInputStream

      public VisibleBufferedInputStream(InputStream in, int bufferSize)
      Creates a new buffer around the given stream.
      Parameters:
      in - The stream to buffer.
      bufferSize - The initial size of the buffer.
  • Method Details

    • read

      public int read() throws IOException
      Specified by:
      read in class InputStream
      Throws:
      IOException
    • peek

      public int peek() throws IOException
      Reads a byte from the buffer without advancing the index pointer.
      Returns:
      byte from the buffer without advancing the index pointer
      Throws:
      IOException - if something wrong happens
    • readRaw

      public byte readRaw()
      Reads byte from the buffer without any checks. This method never reads from the underlaying stream. Before calling this method the ensureBytes(int) method must have been called.
      Returns:
      The next byte from the buffer.
      Throws:
      ArrayIndexOutOfBoundsException - If ensureBytes was not called to make sure the buffer contains the byte.
    • ensureBytes

      public boolean ensureBytes(int n) throws IOException
      Ensures that the buffer contains at least n bytes. This method invalidates the buffer and index fields.
      Parameters:
      n - The amount of bytes to ensure exists in buffer
      Returns:
      true if required bytes are available and false if EOF
      Throws:
      IOException - If reading of the wrapped stream failed.
    • ensureBytes

      public boolean ensureBytes(int n, boolean block) throws IOException
      Ensures that the buffer contains at least n bytes. This method invalidates the buffer and index fields.
      Parameters:
      n - The amount of bytes to ensure exists in buffer
      block - whether or not to block the IO
      Returns:
      true if required bytes are available and false if EOF or the parameter block was false and socket timeout occurred.
      Throws:
      IOException - If reading of the wrapped stream failed.
    • readMore

      private boolean readMore(int wanted, boolean block) throws IOException
      Reads more bytes into the buffer.
      Parameters:
      wanted - How much should be at least read.
      Returns:
      True if at least some bytes were read.
      Throws:
      IOException - If reading of the wrapped stream failed.
    • doubleBuffer

      private void doubleBuffer()
      Doubles the size of the buffer.
    • compact

      private void compact()
      Compacts the unread bytes of the buffer to the beginning of the buffer.
    • moveBufferTo

      private void moveBufferTo(byte[] dest)
      Moves bytes from the buffer to the beginning of the destination buffer. Also sets the index and endIndex variables.
      Parameters:
      dest - The destination buffer.
    • read

      public int read(byte[] to, int off, int len) throws IOException
      Overrides:
      read in class InputStream
      Throws:
      IOException
    • skip

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

      public int available() throws IOException
      Overrides:
      available in class InputStream
      Throws:
      IOException
    • 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
    • getBuffer

      public byte[] getBuffer()
      Returns direct handle to the used buffer. Use the ensureBytes(int) to prefill required bytes the buffer and getIndex() to fetch the current position of the buffer.
      Returns:
      The underlaying buffer.
    • getIndex

      public int getIndex()
      Returns the current read position in the buffer.
      Returns:
      the current read position in the buffer.
    • scanCStringLength

      public int scanCStringLength() throws IOException
      Scans the length of the next null terminated string (C-style string) from the stream.
      Returns:
      The length of the next null terminated string.
      Throws:
      IOException - If reading of stream fails.
      EOFException - If the stream did not contain any null terminators.
    • setTimeoutRequested

      public void setTimeoutRequested(boolean timeoutRequested)
    • getWrapped

      public InputStream getWrapped()
      Returns:
      the wrapped stream