org.apache.poi.util
Class LittleEndian

java.lang.Object
  org.apache.poi.util.LittleEndian

All Implemented Interfaces:

LittleEndianConsts

public class LittleEndian
extends java.lang.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.

Author:

Marc Johnson (mjohnson at apache dot org), Andrew Oliver (acoliver at apache dot org)

Nested Class Summary

static class

LittleEndian.BufferUnderrunException Exception to handle buffer underruns

Field Summary

Fields inherited from interface org.apache.poi.util.LittleEndianConsts

BYTE_SIZE, DOUBLE_SIZE, INT_SIZE, LONG_SIZE, SHORT_SIZE

Method Summary

static byte[]	getByteArray(byte[] data, int offset, int size) Copy a portion of a byte array
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	getUnsignedByte(byte[] data, int offset) Deprecated. Use getUByte(byte[], int) instead
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: data[offset] = (byte)value;
static void	putDouble(byte[] data, int offset, double value) put a double value into a byte array
static void	putDouble(double value, java.io.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, java.io.OutputStream outputStream) put a float value into a byte array
static void	putInt(byte[] data, int value) Deprecated. Use putInt(byte[], int, int) instead
static void	putInt(byte[] data, int offset, int value) put an int value into a byte array
static void	putInt(int value, java.io.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, java.io.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(byte[] data, short value) Deprecated. Use putShort(byte[], int, short) instead
static void	putShort(java.io.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(byte[] data, long value) Deprecated. Use putUInt(byte[], int, long) instead
static void	putUInt(long value, java.io.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, java.io.OutputStream outputStream) Put unsigned short into output stream
static int	readInt(java.io.InputStream stream) get an int value from an InputStream
static long	readLong(java.io.InputStream stream) get a long value from an InputStream
static short	readShort(java.io.InputStream stream) get a short value from an InputStream
static int	readUShort(java.io.InputStream stream)
static int	ubyteToInt(byte b) Convert an 'unsigned' byte to an integer.

Methods inherited from class java.lang.Object

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

Method Detail

getByteArray

public static byte[] getByteArray(byte[] data,
                                  int offset,
                                  int size)

Copy a portion of a byte array

Parameters:

data - the original byte array

offset - Where to start copying from.

size - Number of bytes to copy.

Returns:

The byteArray value

Throws:

java.lang.IndexOutOfBoundsException - - if copying would cause access of data outside array bounds.

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:

java.lang.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

getUnsignedByte

@Deprecated
public static int getUnsignedByte(byte[] data,
                                             int offset)

Deprecated. Use getUByte(byte[], int) instead

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 32 bit integer

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,
                             java.io.OutputStream outputStream)
                      throws java.io.IOException

put a double value into a byte array

Parameters:

value - the double (64-bit) value

outputStream - output stream

Throws:

java.io.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,
                            java.io.OutputStream outputStream)
                     throws java.io.IOException

put a float value into a byte array

Parameters:

value - the float (32-bit) value

outputStream - output stream

Throws:

java.io.IOException - if an I/O error occurs

putInt

@Deprecated
public static void putInt(byte[] data,
                                     int value)

Deprecated. Use putInt(byte[], int, int) instead

put an int value into beginning of a byte array

Parameters:

data - the byte array

value - the int (32-bit) value

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,
                          java.io.OutputStream outputStream)
                   throws java.io.IOException

Put int into output stream

Parameters:

value - the int (32-bit) value

outputStream - output stream

Throws:

java.io.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,
                           java.io.OutputStream outputStream)
                    throws java.io.IOException

Put long into output stream

Parameters:

value - the long (64-bit) value

outputStream - output stream

Throws:

java.io.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

@Deprecated
public static void putShort(byte[] data,
                                       short value)

Deprecated. Use putShort(byte[], int, short) instead

put a short value into beginning of a byte array

Parameters:

data - the byte array

value - the short (16-bit) value

putShort

public static void putShort(java.io.OutputStream outputStream,
                            short value)
                     throws java.io.IOException

Put signed short into output stream

Parameters:

value - the short (16-bit) value

outputStream - output stream

Throws:

java.io.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:

java.lang.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:

java.lang.ArrayIndexOutOfBoundsException - may be thrown

putUInt

@Deprecated
public static void putUInt(byte[] data,
                                      long value)

Deprecated. Use putUInt(byte[], int, long) instead

put an unsigned int value into beginning of a byte array

Parameters:

data - the byte array

value - the int (32-bit) value

putUInt

public static void putUInt(long value,
                           java.io.OutputStream outputStream)
                    throws java.io.IOException

Put unsigned int into output stream

Parameters:

value - the int (32-bit) value

outputStream - output stream

Throws:

java.io.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:

java.lang.ArrayIndexOutOfBoundsException - may be thrown

putUShort

public static void putUShort(int value,
                             java.io.OutputStream outputStream)
                      throws java.io.IOException

Put unsigned short into output stream

Parameters:

value - the unsigned short (16-bit) value

outputStream - output stream

Throws:

java.io.IOException - if an I/O error occurs

readInt

public static int readInt(java.io.InputStream stream)
                   throws java.io.IOException,
                          LittleEndian.BufferUnderrunException

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:

java.io.IOException - will be propagated back to the caller

LittleEndian.BufferUnderrunException - if the stream cannot provide enough bytes

readLong

public static long readLong(java.io.InputStream stream)
                     throws java.io.IOException,
                            LittleEndian.BufferUnderrunException

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:

java.io.IOException - will be propagated back to the caller

LittleEndian.BufferUnderrunException - if the stream cannot provide enough bytes

readShort

public static short readShort(java.io.InputStream stream)
                       throws java.io.IOException,
                              LittleEndian.BufferUnderrunException

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:

java.io.IOException - will be propagated back to the caller

LittleEndian.BufferUnderrunException - if the stream cannot provide enough bytes

readUShort

public static int readUShort(java.io.InputStream stream)
                      throws java.io.IOException,
                             LittleEndian.BufferUnderrunException

Throws:

java.io.IOException

LittleEndian.BufferUnderrunException

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