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org.apache.poi.util
Class LittleEndian

java.lang.Object
  extended by 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.

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 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, 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 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(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(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 long readUInt(java.io.InputStream stream)
          get an unsigned int 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

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

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

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

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

readUInt

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