net.wimpi.modbus.util
Class ModbusUtil

java.lang.Object
  net.wimpi.modbus.util.ModbusUtil

public final class ModbusUtil
extends Object

Helper class that provides utility methods.

Version:

@version@ (@date@)

Author:

Dieter Wimberger, John Charlton

Field Summary

private static short[]	auchCRCHi
private static short[]	auchCRCLo
private static BytesOutputStream	m_ByteOut

Constructor Summary

ModbusUtil()

Method Summary

static int[]	calculateCRC(byte[] data, int offset, int len)
static int	calculateLRC(byte[] data, int off, int len)
static byte[]	doubleToRegisters(double d) Converts a double value to a byte[8].
static byte[]	floatToRegisters(float f) Converts a float value to a byte[4] binary float value.
static byte	hiByte(int wd)
static byte[]	intToRegisters(int v) Converts an int value to a byte[4] array.
static byte[]	longToRegisters(long v) Converts a long value to a byte[8].
static byte	lowByte(int wd) Returs the low byte of an integer word.
static int	makeWord(int hibyte, int lowbyte)
static double	registersToDouble(byte[] bytes) Converts a byte[8] binary double value into a double primitive.
static float	registersToFloat(byte[] bytes) Converts a byte[4] binary float value to a float primitive.
static int	registersToInt(byte[] bytes) Converts a byte[4] binary int value to a primitive int. The value returned is:
static long	registersToLong(byte[] bytes) Converts a byte[8] binary long value into a long primitive.
static short	registerToShort(byte[] bytes) Converts the given register (16-bit value) into a short.
static short	registerToShort(byte[] bytes, int idx) Converts the register (16-bit value) at the given index into a short.
static int	registerToUnsignedShort(byte[] bytes) Converts the register (a 16 bit value) into an unsigned short.
static byte[]	shortToRegister(short s) Converts the given short into a register (2 bytes).
static String	toHex(byte[] data) Returns the given byte[] as hex encoded string.
static String	toHex(byte[] data, int off, int length) Returns a String containing unsigned hexadecimal numbers as digits.
static byte[]	toHex(int i) Returns a byte[] containing the given byte as unsigned hexadecimal number digits.
static String	toHex(ModbusMessage msg) Converts a ModbusMessage instance into a hex encoded string representation.
static int	unsignedByteToInt(byte b) Converts an unsigned byte to an integer.
static byte[]	unsignedShortToRegister(int v) Converts the given unsigned short into a register (2 bytes).

Methods inherited from class java.lang.Object

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

Field Detail

m_ByteOut

private static BytesOutputStream m_ByteOut

auchCRCHi

private static final short[] auchCRCHi

auchCRCLo

private static final short[] auchCRCLo

Constructor Detail

ModbusUtil

public ModbusUtil()

Method Detail

toHex

public static final String toHex(ModbusMessage msg)

Converts a ModbusMessage instance into a hex encoded string representation.

Parameters:

msg - the message to be converted.

Returns:

the converted hex encoded string representation of the message.

toHex

public static final String toHex(byte[] data)

Returns the given byte[] as hex encoded string.

Parameters:

data - a byte[] array.

Returns:

a hex encoded String.

toHex

public static final String toHex(byte[] data,
                                 int off,
                                 int length)

Returns a String containing unsigned hexadecimal numbers as digits. The String will coontain two hex digit characters for each byte from the passed in byte[].
The bytes will be separated by a space character.

Parameters:

data - the array of bytes to be converted into a hex-string.

off - the offset to start converting from.

length - the number of bytes to be converted.

Returns:

the generated hexadecimal representation as String.

toHex

public static final byte[] toHex(int i)

Returns a byte[] containing the given byte as unsigned hexadecimal number digits.

Parameters:

i - the int to be converted into a hex string.

Returns:

the generated hexadecimal representation as byte[].

registerToUnsignedShort

public static final int registerToUnsignedShort(byte[] bytes)

Converts the register (a 16 bit value) into an unsigned short. The value returned is:

(((a & 0xff) << 8) | (b & 0xff))
 

This conversion has been taken from the documentation of the DataInput interface.

Parameters:

bytes - a register as byte[2].

Returns:

the unsigned short value as int.

See Also:

DataInput

unsignedShortToRegister

public static final byte[] unsignedShortToRegister(int v)

Converts the given unsigned short into a register (2 bytes). The byte values in the register, in the order shown, are:

 (byte)(0xff & (v >> 8))
 (byte)(0xff & v)
 

This conversion has been taken from the documentation of the DataOutput interface.

Parameters:

v -

Returns:

the register as byte[2].

See Also:

DataOutput

registerToShort

public static final short registerToShort(byte[] bytes)

Converts the given register (16-bit value) into a short. The value returned is:

 (short)((a << 8) | (b & 0xff))
 

This conversion has been taken from the documentation of the DataInput interface.

Parameters:

bytes - bytes a register as byte[2].

Returns:

the signed short as short.

registerToShort

public static final short registerToShort(byte[] bytes,
                                          int idx)

Converts the register (16-bit value) at the given index into a short. The value returned is:

 (short)((a << 8) | (b & 0xff))
 

This conversion has been taken from the documentation of the DataInput interface.

Parameters:

bytes - a byte[] containing a short value.

idx - an offset into the given byte[].

Returns:

the signed short as short.

shortToRegister

public static final byte[] shortToRegister(short s)

Converts the given short into a register (2 bytes). The byte values in the register, in the order shown, are:

 (byte)(0xff & (v >> 8))
 (byte)(0xff & v)
 

Parameters:

s -

Returns:

a register containing the given short value.

registersToInt

public static final int registersToInt(byte[] bytes)

Converts a byte[4] binary int value to a primitive int.
The value returned is:

 
 (((a & 0xff) << 24) | ((b & 0xff) << 16) |
  ((c & 0xff) << 8) | (d & 0xff))
 

Parameters:

bytes - registers as byte[4].

Returns:

the integer contained in the given register bytes.

intToRegisters

public static final byte[] intToRegisters(int v)

Converts an int value to a byte[4] array.

Parameters:

v - the value to be converted.

Returns:

a byte[4] containing the value.

registersToLong

public static final long registersToLong(byte[] bytes)

Converts a byte[8] binary long value into a long primitive.

Parameters:

bytes - a byte[8] containing a long value.

Returns:

a long value.

longToRegisters

public static final byte[] longToRegisters(long v)

Converts a long value to a byte[8].

Parameters:

v - the value to be converted.

Returns:

a byte[8] containing the long value.

registersToFloat

public static final float registersToFloat(byte[] bytes)

Converts a byte[4] binary float value to a float primitive.

Parameters:

bytes - the byte[4] containing the float value.

Returns:

a float value.

floatToRegisters

public static final byte[] floatToRegisters(float f)

Converts a float value to a byte[4] binary float value.

Parameters:

f - the float to be converted.

Returns:

a byte[4] containing the float value.

registersToDouble

public static final double registersToDouble(byte[] bytes)

Converts a byte[8] binary double value into a double primitive.

Parameters:

bytes - a byte[8] to be converted.

Returns:

a double value.

doubleToRegisters

public static final byte[] doubleToRegisters(double d)

Converts a double value to a byte[8].

Parameters:

d - the double to be converted.

Returns:

a byte[8].

unsignedByteToInt

public static final int unsignedByteToInt(byte b)

Converts an unsigned byte to an integer.

Parameters:

b - the byte to be converted.

Returns:

an integer containing the unsigned byte value.

lowByte

public static final byte lowByte(int wd)

Returs the low byte of an integer word.

Parameters:

wd -

Returns:

the low byte.

hiByte

public static final byte hiByte(int wd)

Parameters:

wd -

Returns:

the hi byte.

makeWord

public static final int makeWord(int hibyte,
                                 int lowbyte)

Parameters:

hibyte -

lowbyte -

Returns:

a word.

calculateCRC

public static final int[] calculateCRC(byte[] data,
                                       int offset,
                                       int len)

calculateLRC

public static final int calculateLRC(byte[] data,
                                     int off,
                                     int len)