Package com.google.common.io

Class LittleEndianDataInputStream

  • All Implemented Interfaces:
    , , 
    @Beta
@GwtIncompatible
public final class LittleEndianDataInputStream
extends 
implements
    An implementation of that uses little-endian byte ordering for reading short, int, float, double, and long values.

    Note: This class intentionally violates the specification of its supertype DataInput, which explicitly requires big-endian byte order.

    Since:
    8.0
    Author:
    Chris Nokleberg, Keith Bottner

    • Field Summary

      • Fields inherited from class java.io.

    • Constructor Summary

      Constructors 
      Constructor Description
       in)
      Creates a LittleEndianDataInputStream that wraps the given stream.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      boolean readBoolean()
      Reads one input byte and returns true if that byte is nonzero, false if that byte is zero.
      byte readByte()
      Reads and returns one input byte.
      char readChar()
      Reads a char as specified by , except using little-endian byte order.
      double readDouble()
      Reads a double as specified by , except using little-endian byte order.
      float readFloat()
      Reads a float as specified by , except using little-endian byte order.
      void readFully​(byte[] b)
      Reads some bytes from an input stream and stores them into the buffer array b.
      void readFully​(byte[] b, int off, int len)
      Reads len bytes from an input stream.
      int readInt()
      Reads an integer as specified by , except using little-endian byte order.
      readLine()
      This method will throw an .
      long readLong()
      Reads a long as specified by , except using little-endian byte order.
      short readShort()
      Reads a short as specified by , except using little-endian byte order.
      int readUnsignedByte()
      Reads one input byte, zero-extends it to type int, and returns the result, which is therefore in the range 0 through 255.
      int readUnsignedShort()
      Reads an unsigned short as specified by , except using little-endian byte order.
      readUTF()
      Reads in a string that has been encoded using a modified UTF-8 format.
      int skipBytes​(int n)
      Makes an attempt to skip over n bytes of data from the input stream, discarding the skipped bytes.

      • Methods inherited from class java.io.

        , , , , , , , ,

      • Methods inherited from class java.io.

        , , , ,

      • Methods inherited from class java.lang.

        , , , , , , , , , ,

    • Constructor Detail

      • LittleEndianDataInputStream

        public  in)
        Creates a LittleEndianDataInputStream that wraps the given stream.
        Parameters:
        in - the stream to delegate to

    • Method Detail

      • readLine

        public  readLine()
        This method will throw an .
        Specified by:
         in interface 
        Returns:
        the next line of text from the input stream, or null if the end of file is encountered before a byte can be read.

      • readFully

        public void readFully​(byte[] b)
               throws
        Description copied from interface: 
        Reads some bytes from an input stream and stores them into the buffer array b. The number of bytes read is equal to the length of b.

        This method blocks until one of the following conditions occurs:

        • b.length bytes of input data are available, in which case a normal return is made.
        • End of file is detected, in which case an EOFException is thrown.
        • An I/O error occurs, in which case an IOException other than EOFException is thrown.

        If b is null, a NullPointerException is thrown. If b.length is zero, then no bytes are read. Otherwise, the first byte read is stored into element b[0], the next one into b[1], and so on. If an exception is thrown from this method, then it may be that some but not all bytes of b have been updated with data from the input stream.

        Specified by:
         in interface 
        Parameters:
        b - the buffer into which the data is read.
        Throws:
        - if this stream reaches the end before reading all the bytes.
        - if an I/O error occurs.

      • readFully

        public void readFully​(byte[] b,
                      int off,
                      int len)
               throws
        Description copied from interface: 
        Reads len bytes from an input stream.

        This method blocks until one of the following conditions occurs:

        • len bytes of input data are available, in which case a normal return is made.
        • End of file is detected, in which case an EOFException is thrown.
        • An I/O error occurs, in which case an IOException other than EOFException 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. Otherwise, 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.

        Specified by:
         in interface 
        Parameters:
        b - the buffer into which the data is read.
        off - an int specifying the offset in the data array b.
        len - an int specifying the number of bytes to read.
        Throws:
        - if this stream reaches the end before reading all the bytes.
        - if an I/O error occurs.

      • skipBytes

        public int skipBytes​(int n)
              throws
        Description copied from interface: 
        Makes an attempt to skip over n bytes of data from the input stream, discarding the skipped bytes. However, it may skip over some smaller number of bytes, possibly zero. This may result from any of a number of conditions; reaching end of file before n bytes have been skipped is only one possibility. This method never throws an EOFException. The actual number of bytes skipped is returned.
        Specified by:
         in interface 
        Parameters:
        n - the number of bytes to be skipped.
        Returns:
        the number of bytes actually skipped.
        Throws:
        - if an I/O error occurs.

      • readUnsignedByte

        public int readUnsignedByte()
                     throws
        Description copied from interface: 
        Reads one input byte, zero-extends it to type int, and returns the result, which is therefore in the range 0 through 255. This method is suitable for reading the byte written by the writeByte method of interface DataOutput if the argument to writeByte was intended to be a value in the range 0 through 255.
        Specified by:
         in interface 
        Returns:
        the unsigned 8-bit value read.
        Throws:
        - if this stream reaches the end before reading all the bytes.
        - if an I/O error occurs.

      • readUnsignedShort

        public int readUnsignedShort()
                      throws
        Reads an unsigned short as specified by , except using little-endian byte order.
        Specified by:
         in interface 
        Returns:
        the next two bytes of the input stream, interpreted as an unsigned 16-bit integer in little-endian byte order
        Throws:
        - if an I/O error occurs

      • readInt

        public int readInt()
            throws
        Reads an integer as specified by , except using little-endian byte order.
        Specified by:
         in interface 
        Returns:
        the next four bytes of the input stream, interpreted as an int in little-endian byte order
        Throws:
        - if an I/O error occurs

      • readLong

        public long readLong()
              throws
        Reads a long as specified by , except using little-endian byte order.
        Specified by:
         in interface 
        Returns:
        the next eight bytes of the input stream, interpreted as a long in little-endian byte order
        Throws:
        - if an I/O error occurs

      • readFloat

        public float readFloat()
                throws
        Reads a float as specified by , except using little-endian byte order.
        Specified by:
         in interface 
        Returns:
        the next four bytes of the input stream, interpreted as a float in little-endian byte order
        Throws:
        - if an I/O error occurs

      • readDouble

        public double readDouble()
                  throws
        Reads a double as specified by , except using little-endian byte order.
        Specified by:
         in interface 
        Returns:
        the next eight bytes of the input stream, interpreted as a double in little-endian byte order
        Throws:
        - if an I/O error occurs

      • readUTF

        public  readUTF()
               throws
        Description copied from interface: 
        Reads in a string that has been encoded using a modified UTF-8 format. The general contract of readUTF is that it reads a representation of a Unicode character string encoded in modified UTF-8 format; this string of characters is then returned as a String.

        First, two bytes are read and used to construct an unsigned 16-bit integer in exactly the manner of the readUnsignedShort method . This integer value is called the UTF length and specifies the number of additional bytes to be read. These bytes are then converted to characters by considering them in groups. The length of each group is computed from the value of the first byte of the group. The byte following a group, if any, is the first byte of the next group.

        If the first byte of a group matches the bit pattern 0xxxxxxx (where x means "may be 0 or 1"), then the group consists of just that byte. The byte is zero-extended to form a character.

        If the first byte of a group matches the bit pattern 110xxxxx, then the group consists of that byte a and a second byte b. If there is no byte b (because byte a was the last of the bytes to be read), or if byte b does not match the bit pattern 10xxxxxx, then a UTFDataFormatException is thrown. Otherwise, the group is converted to the character: 

        (char)(((a & 0x1F) << 6) | (b & 0x3F))
        If the first byte of a group matches the bit pattern 1110xxxx, then the group consists of that byte a and two more bytes b and c. If there is no byte c (because byte a was one of the last two of the bytes to be read), or either byte b or byte c does not match the bit pattern 10xxxxxx, then a UTFDataFormatException is thrown. Otherwise, the group is converted to the character: 
        
 (char)(((a & 0x0F) << 12) | ((b & 0x3F) << 6) | (c & 0x3F))
        If the first byte of a group matches the pattern 1111xxxx or the pattern 10xxxxxx, then a UTFDataFormatException is thrown.

        If end of file is encountered at any time during this entire process, then an EOFException is thrown.

        After every group has been converted to a character by this process, the characters are gathered, in the same order in which their corresponding groups were read from the input stream, to form a String, which is returned.

        The writeUTF method of interface DataOutput may be used to write data that is suitable for reading by this method.

        Specified by:
         in interface 
        Returns:
        a Unicode string.
        Throws:
        - if this stream reaches the end before reading all the bytes.
        - if an I/O error occurs.
        - if the bytes do not represent a valid modified UTF-8 encoding of a string.

      • readShort

        public short readShort()
                throws
        Reads a short as specified by , except using little-endian byte order.
        Specified by:
         in interface 
        Returns:
        the next two bytes of the input stream, interpreted as a short in little-endian byte order.
        Throws:
        - if an I/O error occurs.

      • readChar

        public char readChar()
              throws
        Reads a char as specified by , except using little-endian byte order.
        Specified by:
         in interface 
        Returns:
        the next two bytes of the input stream, interpreted as a char in little-endian byte order
        Throws:
        - if an I/O error occurs

      • readByte

        public byte readByte()
              throws
        Description copied from interface: 
        Reads and returns one input byte. The byte is treated as a signed value in the range -128 through 127, inclusive. This method is suitable for reading the byte written by the writeByte method of interface DataOutput.
        Specified by:
         in interface 
        Returns:
        the 8-bit value read.
        Throws:
        - if this stream reaches the end before reading all the bytes.
        - if an I/O error occurs.

      • readBoolean

        public boolean readBoolean()
                    throws
        Description copied from interface: 
        Reads one input byte and returns true if that byte is nonzero, false if that byte is zero. This method is suitable for reading the byte written by the writeBoolean method of interface DataOutput.
        Specified by:
         in interface 
        Returns:
        the boolean value read.
        Throws:
        - if this stream reaches the end before reading all the bytes.
        - if an I/O error occurs.