Package it.unimi.dsi.io

Class ByteBufferInputStream

  • All Implemented Interfaces:
    it.unimi.dsi.fastutil.io.MeasurableStream, it.unimi.dsi.fastutil.io.RepositionableStream, java.io.Closeable, java.lang.AutoCloseable
    public class ByteBufferInputStream
extends it.unimi.dsi.fastutil.io.MeasurableInputStream
implements it.unimi.dsi.fastutil.io.RepositionableStream
    A bridge between byte buffers and input streams.

    Java's memory-mapping facilities have the severe limitation of mapping at most Integer.MAX_VALUE bytes, as they expose the content of a file using a MappedByteBuffer. This class can expose a file of arbitrary length as a repositionable MeasurableInputStream that is actually based on an array of MappedByteBuffers, each mapping a chunk of CHUNK_SIZE bytes.

    Since:
    1.2
    Author:
    Sebastiano Vigna

    • Constructor Summary

      Constructors 
      Modifier Constructor Description
        ByteBufferInputStream​(java.nio.ByteBuffer byteBuffer)
      Creates a new byte-buffer input stream from a single ByteBuffer.
      protected ByteBufferInputStream​(java.nio.ByteBuffer[] byteBuffer, long size, int curr, boolean[] readyToUse)
      Creates a new byte-buffer input stream.

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      int available()  
      ByteBufferInputStream copy()  
      long length()  
      static ByteBufferInputStream map​(java.nio.channels.FileChannel fileChannel)
      Creates a new read-only byte-buffer input stream by mapping a given file channel.
      static ByteBufferInputStream map​(java.nio.channels.FileChannel fileChannel, java.nio.channels.FileChannel.MapMode mapMode)
      Creates a new byte-buffer input stream by mapping a given file channel.
      void mark​(int unused)  
      boolean markSupported()  
      long position()  
      void position​(long newPosition)  
      int read()  
      int read​(byte[] b, int offset, int length)  
      void reset()  
      long skip​(long n)  

      • Methods inherited from class java.io.InputStream

        close, nullInputStream, read, readAllBytes, readNBytes, readNBytes, transferTo

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • ByteBufferInputStream

        public ByteBufferInputStream​(java.nio.ByteBuffer byteBuffer)
        Creates a new byte-buffer input stream from a single ByteBuffer.
        Parameters:
        byteBuffer - the underlying byte buffer.

      • ByteBufferInputStream

        protected ByteBufferInputStream​(java.nio.ByteBuffer[] byteBuffer,
                                long size,
                                int curr,
                                boolean[] readyToUse)
        Creates a new byte-buffer input stream.
        Parameters:
        byteBuffer - the underlying byte buffers.
        size - the sum of the capacities of the byte buffers.
        curr - the current buffer (reading will start at this buffer from its current position).
        readyToUse - an array parallel to byteBuffer specifying which buffers do not need to be duplicated before being used (the process will happen lazily); the array will be used internally by the newly created byte-buffer input stream.

    • Method Detail

      • map

        public static ByteBufferInputStream map​(java.nio.channels.FileChannel fileChannel)
                                 throws java.io.IOException
        Creates a new read-only byte-buffer input stream by mapping a given file channel.
        Parameters:
        fileChannel - the file channel that will be mapped.
        Returns:
        a new read-only byte-buffer input stream over the contents of fileChannel.
        Throws:
        java.io.IOException

      • map

        public static ByteBufferInputStream map​(java.nio.channels.FileChannel fileChannel,
                                        java.nio.channels.FileChannel.MapMode mapMode)
                                 throws java.io.IOException
        Creates a new byte-buffer input stream by mapping a given file channel.
        Parameters:
        fileChannel - the file channel that will be mapped.
        mapMode - this must be FileChannel.MapMode.READ_ONLY.
        Returns:
        a new byte-buffer input stream over the contents of fileChannel.
        Throws:
        java.io.IOException

      • available

        public int available()
        Overrides:
        available in class java.io.InputStream

      • markSupported

        public boolean markSupported()
        Overrides:
        markSupported in class java.io.InputStream

      • mark

        public void mark​(int unused)
        Overrides:
        mark in class java.io.InputStream

      • reset

        public void reset()
           throws java.io.IOException
        Overrides:
        reset in class java.io.InputStream
        Throws:
        java.io.IOException

      • skip

        public long skip​(long n)
          throws java.io.IOException
        Overrides:
        skip in class java.io.InputStream
        Throws:
        java.io.IOException

      • read

        public int read()
        Specified by:
        read in class java.io.InputStream

      • read

        public int read​(byte[] b,
                int offset,
                int length)
        Overrides:
        read in class java.io.InputStream

      • length

        public long length()
        Specified by:
        length in interface it.unimi.dsi.fastutil.io.MeasurableStream

      • position

        public long position()
        Specified by:
        position in interface it.unimi.dsi.fastutil.io.MeasurableStream
        Specified by:
        position in interface it.unimi.dsi.fastutil.io.RepositionableStream

      • position

        public void position​(long newPosition)
        Specified by:
        position in interface it.unimi.dsi.fastutil.io.RepositionableStream