Module org.sejda.commons
Package org.sejda.commons

Class FastByteArrayOutputStream

java.lang.Object
java.io.OutputStream
org.sejda.commons.FastByteArrayOutputStream
All Implemented Interfaces:
Closeable, Flushable, AutoCloseable
public class FastByteArrayOutputStream extends OutputStream
A speedy alternative to ByteArrayOutputStream. Note that this variant does not extend ByteArrayOutputStream

Unlike ByteArrayOutputStream, this implementation is backed by a LinkedList of byte[] instead of 1 constantly resizing byte[]. It does not copy buffers when it gets expanded.

The initial buffer is only created when the stream is first written. There is also no copying of the internal buffer if its contents is extracted with the writeTo(OutputStream) method.

  • Field Details

    • DEFAULT_BLOCK_SIZE

      private static final int DEFAULT_BLOCK_SIZE
      See Also:

    • MAX_BLOCK_SIZE

      private static final int MAX_BLOCK_SIZE
      See Also:

    • buffers

      private final LinkedList<byte[]> buffers

    • initialBlockSize

      private final int initialBlockSize

    • nextBlockSize

      private int nextBlockSize

    • alreadyBufferedSize

      private int alreadyBufferedSize

    • index

      private int index

    • closed

      private boolean closed

  • Constructor Details

    • FastByteArrayOutputStream

      public FastByteArrayOutputStream()
      Create a new FastByteArrayOutputStream with the default initial capacity of 256 bytes.

    • FastByteArrayOutputStream

      public FastByteArrayOutputStream(int initialBlockSize)
      Create a new FastByteArrayOutputStream with the specified initial capacity.
      Parameters:
      initialBlockSize - the initial buffer size in bytes

  • Method Details

    • write

      public void write(int datum) throws IOException
      Specified by:
      write in class OutputStream
      Throws:
      IOException

    • write

      public void write(byte[] data, int offset, int length) throws IOException
      Overrides:
      write in class OutputStream
      Throws:
      IOException

    • close

      public void close()
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Overrides:
      close in class OutputStream

    • toString

      public String toString()
      Convert the buffer's contents into a string decoding bytes using the platform's default character set. The length of the new String is a function of the character set, and hence may not be equal to the size of the buffer.

      This method always replaces malformed-input and unmappable-character sequences with the default replacement string for the platform's default character set. The CharsetDecoder class should be used when more control over the decoding process is required.

      Overrides:
      toString in class Object
      Returns:
      a String decoded from the buffer's contents

    • size

      public int size()
      Return the number of bytes stored in this FastByteArrayOutputStream.

    • toByteArrayUnsafe

      public byte[] toByteArrayUnsafe()
      Convert the stream's data to a byte array and return the byte array.

      Also replaces the internal structures with the byte array to conserve memory: if the byte array is being made anyways, mind as well as use it. This approach also means that if this method is called twice without any writes in between, the second call is a no-op.

      This method is "unsafe" as it returns the internal buffer. Callers should not modify the returned buffer.

      Returns:
      the current contents of this output stream, as a byte array.
      See Also:

    • toByteArray

      public byte[] toByteArray()

    • toByteArraySafe

      public byte[] toByteArraySafe()
      Creates a newly allocated byte array.

      Its size is the current size of this output stream and the valid contents of the buffer have been copied into it.

      Returns:
      the current contents of this output stream, as a byte array.
      See Also:

    • reset

      public void reset()
      Reset the contents of this FastByteArrayOutputStream.

      All currently accumulated output in the output stream is discarded. The output stream can be used again.

    • getInputStream

      public InputStream getInputStream()
      Get an InputStream to retrieve the data in this OutputStream.

      Note that if any methods are called on the OutputStream (including, but not limited to, any of the write methods, reset(), toByteArray(), and toByteArrayUnsafe()) then the InputStream 's behavior is undefined.

      Returns:
      InputStream of the contents of this OutputStream

    • writeTo

      public void writeTo(OutputStream out) throws IOException
      Write the buffers content to the given OutputStream.
      Parameters:
      out - the OutputStream to write to
      Throws:
      IOException

    • resize

      public void resize(int targetCapacity)
      Resize the internal buffer size to a specified capacity.
      Parameters:
      targetCapacity - the desired size of the buffer
      Throws:
      IllegalArgumentException - if the given capacity is smaller than the actual size of the content stored in the buffer already
      See Also:

    • addBuffer

      private void addBuffer(int minCapacity)
      Create a new buffer and store it in the LinkedList

      Adds a new buffer that can store at least minCapacity bytes.

    • nextPowerOf2

      private static int nextPowerOf2(int val)
      Get the next power of 2 of a number (ex, the next power of 2 of 119 is 128).

    • assertIsTrue

      private static void assertIsTrue(Boolean condition, String message)