Package org.apache.poi.util

Class LittleEndian

  • All Implemented Interfaces:
    LittleEndianConsts
    @Internal
public final class LittleEndian
extends Object
implements LittleEndianConsts
    a utility class for handling little-endian numbers, which the 80x86 world is replete with. The methods are all static, and input/output is from/to byte arrays, or from InputStreams.

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static double getDouble​(byte[] data)
      get a double value from a byte array, reads it in little endian format then converts the resulting revolting IEEE 754 (curse them) floating point number to a happy java double
      static double getDouble​(byte[] data, int offset)
      get a double value from a byte array, reads it in little endian format then converts the resulting revolting IEEE 754 (curse them) floating point number to a happy java double
      static float getFloat​(byte[] data)
      get a float value from a byte array, reads it in little endian format then converts the resulting revolting IEEE 754 (curse them) floating point number to a happy java float
      static float getFloat​(byte[] data, int offset)
      get a float value from a byte array, reads it in little endian format then converts the resulting revolting IEEE 754 (curse them) floating point number to a happy java float
      static int getInt​(byte[] data)
      get an int value from the beginning of a byte array
      static int getInt​(byte[] data, int offset)
      get an int value from a byte array
      static long getLong​(byte[] data)
      get a long value from a byte array
      static long getLong​(byte[] data, int offset)
      get a long value from a byte array
      static short getShort​(byte[] data)
      get a short value from the beginning of a byte array
      static short getShort​(byte[] data, int offset)
      get a short value from a byte array
      static short[] getShortArray​(byte[] data, int offset, int size)
      Read short array
      static short getUByte​(byte[] data)
      get the unsigned value of a byte.
      static short getUByte​(byte[] data, int offset)
      get the unsigned value of a byte.
      static long getUInt​(byte[] data)
      get an unsigned int value from a byte array
      static long getUInt​(byte[] data, int offset)
      get an unsigned int value from a byte array
      static int getUShort​(byte[] data)
      get an unsigned short value from the beginning of a byte array
      static int getUShort​(byte[] data, int offset)
      get an unsigned short value from a byte array
      static void putByte​(byte[] data, int offset, int value)
      executes:
      static void putDouble​(byte[] data, int offset, double value)
      put a double value into a byte array
      static void putDouble​(double value, OutputStream outputStream)
      put a double value into a byte array
      static void putFloat​(byte[] data, int offset, float value)
      put a float value into a byte array
      static void putFloat​(float value, OutputStream outputStream)
      put a float value into a byte array
      static void putInt​(byte[] data, int offset, int value)
      put an int value into a byte array
      static void putInt​(int value, OutputStream outputStream)
      Put int into output stream
      static void putLong​(byte[] data, int offset, long value)
      put a long value into a byte array
      static void putLong​(long value, OutputStream outputStream)
      Put long into output stream
      static void putShort​(byte[] data, int offset, short value)
      put a short value into a byte array
      static void putShort​(OutputStream outputStream, short value)
      Put signed short into output stream
      static void putShortArray​(byte[] data, int startOffset, short[] value)
      Stores short array in buffer
      static void putUByte​(byte[] data, int offset, short value)
      put an unsigned byte value into a byte array
      static void putUInt​(byte[] data, int offset, long value)
      put an unsigned int value into a byte array
      static void putUInt​(long value, OutputStream outputStream)
      Put unsigned int into output stream
      static void putUShort​(byte[] data, int offset, int value)
      put an unsigned short value into a byte array
      static void putUShort​(int value, OutputStream outputStream)
      Put unsigned short into output stream
      static int readInt​(InputStream stream)
      get an int value from an InputStream
      static long readLong​(InputStream stream)
      get a long value from an InputStream
      static short readShort​(InputStream stream)
      get a short value from an InputStream
      static long readUInt​(InputStream stream)
      get an unsigned int value from an InputStream
      static int readUShort​(InputStream stream)  
      static int ubyteToInt​(byte b)
      Convert an 'unsigned' byte to an integer.

    • Method Detail

      • getDouble

        public static double getDouble​(byte[] data)
        get a double value from a byte array, reads it in little endian format then converts the resulting revolting IEEE 754 (curse them) floating point number to a happy java double
        Parameters:
        data - the byte array
        Returns:
        the double (64-bit) value

      • getDouble

        public static double getDouble​(byte[] data,
                               int offset)
        get a double value from a byte array, reads it in little endian format then converts the resulting revolting IEEE 754 (curse them) floating point number to a happy java double
        Parameters:
        data - the byte array
        offset - a starting offset into the byte array
        Returns:
        the double (64-bit) value

      • getFloat

        public static float getFloat​(byte[] data)
        get a float value from a byte array, reads it in little endian format then converts the resulting revolting IEEE 754 (curse them) floating point number to a happy java float
        Parameters:
        data - the byte array
        Returns:
        the double (64-bit) value

      • getFloat

        public static float getFloat​(byte[] data,
                             int offset)
        get a float value from a byte array, reads it in little endian format then converts the resulting revolting IEEE 754 (curse them) floating point number to a happy java float
        Parameters:
        data - the byte array
        offset - a starting offset into the byte array
        Returns:
        the double (64-bit) value

      • getInt

        public static int getInt​(byte[] data)
        get an int value from the beginning of a byte array
        Parameters:
        data - the byte array
        Returns:
        the int (32-bit) value

      • getInt

        public static int getInt​(byte[] data,
                         int offset)
        get an int value from a byte array
        Parameters:
        data - the byte array
        offset - a starting offset into the byte array
        Returns:
        the int (32-bit) value

      • getLong

        public static long getLong​(byte[] data)
        get a long value from a byte array
        Parameters:
        data - the byte array
        Returns:
        the long (64-bit) value

      • getLong

        public static long getLong​(byte[] data,
                           int offset)
        get a long value from a byte array
        Parameters:
        data - the byte array
        offset - a starting offset into the byte array
        Returns:
        the long (64-bit) value

      • getShort

        public static short getShort​(byte[] data)
        get a short value from the beginning of a byte array
        Parameters:
        data - the byte array
        Returns:
        the short (16-bit) value

      • getShort

        public static short getShort​(byte[] data,
                             int offset)
        get a short value from a byte array
        Parameters:
        data - the byte array
        offset - a starting offset into the byte array
        Returns:
        the short (16-bit) value

      • getShortArray

        public static short[] getShortArray​(byte[] data,
                                    int offset,
                                    int size)
        Read short array
        Parameters:
        data - the original byte array
        offset - Where to start copying from.
        size - Number of bytes to copy.
        Throws:
        IndexOutOfBoundsException - - if read would cause access of data outside array bounds.

      • getUByte

        public static short getUByte​(byte[] data)
        get the unsigned value of a byte.
        Parameters:
        data - the byte array.
        Returns:
        the unsigned value of the byte as a 16 bit short

      • getUByte

        public static short getUByte​(byte[] data,
                             int offset)
        get the unsigned value of a byte.
        Parameters:
        data - the byte array.
        offset - a starting offset into the byte array.
        Returns:
        the unsigned value of the byte as a 16 bit short

      • getUInt

        public static long getUInt​(byte[] data)
        get an unsigned int value from a byte array
        Parameters:
        data - the byte array
        Returns:
        the unsigned int (32-bit) value in a long

      • getUInt

        public static long getUInt​(byte[] data,
                           int offset)
        get an unsigned int value from a byte array
        Parameters:
        data - the byte array
        offset - a starting offset into the byte array
        Returns:
        the unsigned int (32-bit) value in a long

      • getUShort

        public static int getUShort​(byte[] data)
        get an unsigned short value from the beginning of a byte array
        Parameters:
        data - the byte array
        Returns:
        the unsigned short (16-bit) value in an int

      • getUShort

        public static int getUShort​(byte[] data,
                            int offset)
        get an unsigned short value from a byte array
        Parameters:
        data - the byte array
        offset - a starting offset into the byte array
        Returns:
        the unsigned short (16-bit) value in an integer

      • putByte

        public static void putByte​(byte[] data,
                           int offset,
                           int value)
        executes:

        data[offset] = (byte)value;

        Added for consistency with other put~() methods

      • putDouble

        public static void putDouble​(byte[] data,
                             int offset,
                             double value)
        put a double value into a byte array
        Parameters:
        data - the byte array
        offset - a starting offset into the byte array
        value - the double (64-bit) value

      • putDouble

        public static void putDouble​(double value,
                             OutputStream outputStream)
                      throws IOException
        put a double value into a byte array
        Parameters:
        value - the double (64-bit) value
        outputStream - output stream
        Throws:
        IOException - if an I/O error occurs

      • putFloat

        public static void putFloat​(byte[] data,
                            int offset,
                            float value)
        put a float value into a byte array
        Parameters:
        data - the byte array
        offset - a starting offset into the byte array
        value - the float (32-bit) value

      • putFloat

        public static void putFloat​(float value,
                            OutputStream outputStream)
                     throws IOException
        put a float value into a byte array
        Parameters:
        value - the float (32-bit) value
        outputStream - output stream
        Throws:
        IOException - if an I/O error occurs

      • putInt

        public static void putInt​(byte[] data,
                          int offset,
                          int value)
        put an int value into a byte array
        Parameters:
        data - the byte array
        offset - a starting offset into the byte array
        value - the int (32-bit) value

      • putInt

        public static void putInt​(int value,
                          OutputStream outputStream)
                   throws IOException
        Put int into output stream
        Parameters:
        value - the int (32-bit) value
        outputStream - output stream
        Throws:
        IOException - if an I/O error occurs

      • putLong

        public static void putLong​(byte[] data,
                           int offset,
                           long value)
        put a long value into a byte array
        Parameters:
        data - the byte array
        offset - a starting offset into the byte array
        value - the long (64-bit) value

      • putLong

        public static void putLong​(long value,
                           OutputStream outputStream)
                    throws IOException
        Put long into output stream
        Parameters:
        value - the long (64-bit) value
        outputStream - output stream
        Throws:
        IOException - if an I/O error occurs

      • putShort

        public static void putShort​(byte[] data,
                            int offset,
                            short value)
        put a short value into a byte array
        Parameters:
        data - the byte array
        offset - a starting offset into the byte array
        value - the short (16-bit) value

      • putShort

        public static void putShort​(OutputStream outputStream,
                            short value)
                     throws IOException
        Put signed short into output stream
        Parameters:
        value - the short (16-bit) value
        outputStream - output stream
        Throws:
        IOException - if an I/O error occurs

      • putShortArray

        public static void putShortArray​(byte[] data,
                                 int startOffset,
                                 short[] value)
        Stores short array in buffer
        Parameters:
        data - the byte array
        startOffset - a starting offset into the byte array
        value - the short (16-bit) values

      • putUByte

        public static void putUByte​(byte[] data,
                            int offset,
                            short value)
        put an unsigned byte value into a byte array
        Parameters:
        data - the byte array
        offset - a starting offset into the byte array
        value - the short (16-bit) value
        Throws:
        ArrayIndexOutOfBoundsException - may be thrown

      • putUInt

        public static void putUInt​(byte[] data,
                           int offset,
                           long value)
        put an unsigned int value into a byte array
        Parameters:
        data - the byte array
        offset - a starting offset into the byte array
        value - the int (32-bit) value
        Throws:
        ArrayIndexOutOfBoundsException - may be thrown

      • putUInt

        public static void putUInt​(long value,
                           OutputStream outputStream)
                    throws IOException
        Put unsigned int into output stream
        Parameters:
        value - the int (32-bit) value
        outputStream - output stream
        Throws:
        IOException - if an I/O error occurs

      • putUShort

        public static void putUShort​(byte[] data,
                             int offset,
                             int value)
        put an unsigned short value into a byte array
        Parameters:
        data - the byte array
        offset - a starting offset into the byte array
        value - the short (16-bit) value
        Throws:
        ArrayIndexOutOfBoundsException - may be thrown

      • putUShort

        public static void putUShort​(int value,
                             OutputStream outputStream)
                      throws IOException
        Put unsigned short into output stream
        Parameters:
        value - the unsigned short (16-bit) value
        outputStream - output stream
        Throws:
        IOException - if an I/O error occurs

      • readInt

        public static int readInt​(InputStream stream)
                   throws IOException
        get an int value from an InputStream
        Parameters:
        stream - the InputStream from which the int is to be read
        Returns:
        the int (32-bit) value
        Throws:
        IOException - will be propagated back to the caller
        LittleEndian.BufferUnderrunException - if the stream cannot provide enough bytes

      • readUInt

        public static long readUInt​(InputStream stream)
                     throws IOException
        get an unsigned int value from an InputStream
        Parameters:
        stream - the InputStream from which the int is to be read
        Returns:
        the unsigned int (32-bit) value
        Throws:
        IOException - will be propagated back to the caller
        LittleEndian.BufferUnderrunException - if the stream cannot provide enough bytes

      • readLong

        public static long readLong​(InputStream stream)
                     throws IOException
        get a long value from an InputStream
        Parameters:
        stream - the InputStream from which the long is to be read
        Returns:
        the long (64-bit) value
        Throws:
        IOException - will be propagated back to the caller
        LittleEndian.BufferUnderrunException - if the stream cannot provide enough bytes

      • readShort

        public static short readShort​(InputStream stream)
                       throws IOException
        get a short value from an InputStream
        Parameters:
        stream - the InputStream from which the short is to be read
        Returns:
        the short (16-bit) value
        Throws:
        IOException - will be propagated back to the caller
        LittleEndian.BufferUnderrunException - if the stream cannot provide enough bytes

      • ubyteToInt

        public static int ubyteToInt​(byte b)
        Convert an 'unsigned' byte to an integer. ie, don't carry across the sign.
        Parameters:
        b - Description of the Parameter
        Returns:
        Description of the Return Value