net.solarnetwork.io.modbus

Class ModbusByteUtils

java.lang.Object

net.solarnetwork.io.modbus.ModbusByteUtils

public final class ModbusByteUtils
extends Object

Utilities for Modbus byte manipulation.

Method Summary

Modifier and Type	Method and Description
static short	computeCrc(byte[] data, int start, int end) Compute a 16-bit cyclic redundancy check (CRC) value from a range of bytes.
static short[]	decode(byte[] data) Get raw data as signed 16-bit values.
static short[]	decode(byte[] data, int start, int end) Get raw data as signed 16-bit values.
static byte[]	decodeHexPadStart(char[] chars) Convert a hex-encoded string to a byte array.
static byte[]	decodeHexString(String s) Convert a hex-encoded string to a byte array.
static int[]	decodeUnsigned(byte[] data) Get raw data as unsigned 16-bit values.
static int[]	decodeUnsigned(byte[] data, int start, int end) Get raw data as unsigned 16-bit values.
static byte[]	encode(short[] registers) Get raw data from unsigned 16-bit values.
static void	encode(short[] registers, byte[] dest, int offset) Get raw data from unsigned 16-bit values.
static void	encode16(byte[] data, int offset, int value) Encode a 16-bit value into a byte array.
static char[]	encodeChar(byte b, char[] toDigits, char[] dest, int destIndex) Encode a single byte as a character.
static String	encodeHexString(byte[] data, int fromIndex, int toIndex) Encode a byte array into a hex-encoded upper-case string without spaces.
static String	encodeHexString(byte[] data, int fromIndex, int toIndex, boolean space) Encode a byte array into a hex-encoded upper-case string.
static String	encodeHexString(byte[] data, int fromIndex, int toIndex, boolean space, boolean lowerCase) Encode a byte array into a hex-encoded string.
static byte[]	encodeUnsigned(int[] registers) Get raw data from unsigned 16-bit values.
static void	reverse(byte[] data) Reverse a byte array.

Methods inherited from class java.lang.Object

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

Method Detail

computeCrc

public static short computeCrc(byte[] data,
                               int start,
                               int end)

Compute a 16-bit cyclic redundancy check (CRC) value from a range of bytes.

Parameters:

data - the data to compute the CRC value

start - the starting index (inclusive)

end - the ending index (exclusive)

Returns:

the computed CRC value

encodeChar

public static char[] encodeChar(byte b,
                                char[] toDigits,
                                char[] dest,
                                int destIndex)

Encode a single byte as a character.

Parameters:

b - the byte to encode

toDigits - the alphabet to use

dest - the destination character buffer to write the encoded char to

destIndex - the index within dest to write the encoded char at, along with destIndex + 1

Returns:

the dest array

decodeHexString

public static byte[] decodeHexString(String s)

Convert a hex-encoded string to a byte array.

If the string does not have an even number of characters, a 0 will be inserted at the start of the string.

Parameters:

s - the string to decode

Returns:

the bytes, never null

See Also:

decodeHexPadStart(char[])

decodeHexPadStart

public static byte[] decodeHexPadStart(char[] chars)

Convert a hex-encoded string to a byte array.

If the string does not have an even number of characters, a 0 will be inserted at the start of the string.

Parameters:

chars - the characters to decode

Returns:

the bytes, never null

encodeHexString

public static String encodeHexString(byte[] data,
                                     int fromIndex,
                                     int toIndex)

Encode a byte array into a hex-encoded upper-case string without spaces.

Parameters:

data - the data to encode as hex strings

fromIndex - the starting index within data to encode (inclusive)

toIndex - the ending index within data to encode (exclusive)

Returns:

the string, never null

encodeHexString

public static String encodeHexString(byte[] data,
                                     int fromIndex,
                                     int toIndex,
                                     boolean space)

Encode a byte array into a hex-encoded upper-case string.

Parameters:

data - the data to encode as hex strings

fromIndex - the starting index within data to encode (inclusive)

toIndex - the ending index within data to encode (exclusive)

space - true to add a single space character between each hex

Returns:

the string, never null

encodeHexString

public static String encodeHexString(byte[] data,
                                     int fromIndex,
                                     int toIndex,
                                     boolean space,
                                     boolean lowerCase)

Encode a byte array into a hex-encoded string.

Parameters:

data - the data to encode as hex strings

fromIndex - the starting index within data to encode (inclusive)

toIndex - the ending index within data to encode (exclusive)

space - true to add a single space character between each hex

lowerCase - true to use lower case, false for upper case pair

Returns:

the string, never null

encode

public static byte[] encode(short[] registers)

Get raw data from unsigned 16-bit values.

Parameters:

registers - the 16-bit register values, treated as unsigned values

Returns:

the raw data, or null if registers is null

encode

public static void encode(short[] registers,
                          byte[] dest,
                          int offset)

Get raw data from unsigned 16-bit values.

Parameters:

registers - the 16-bit register values, treated as unsigned values

dest - the destination data

offset - the offset within dest to start at

encodeUnsigned

public static byte[] encodeUnsigned(int[] registers)

Get raw data from unsigned 16-bit values.

Parameters:

registers - the 16-bit register values, treated as unsigned 16-bit values

Returns:

the raw data, or null if registers is null

decode

public static short[] decode(byte[] data)

Get raw data as signed 16-bit values.

Parameters:

data - the data

Returns:

a copy of the data as an array of signed 16-bit values in most-to-least (big endian) byte order, or null if data is null

decode

public static short[] decode(byte[] data,
                             int start,
                             int end)

Get raw data as signed 16-bit values.

Parameters:

data - the data

start - the starting offset with data, inclusive

end - the ending offset with data, exclusive

Returns:

a copy of the data as an array of signed 16-bit values in most-to-least (big endian) byte order, or null if data is null

decodeUnsigned

public static int[] decodeUnsigned(byte[] data)

Get raw data as unsigned 16-bit values.

Parameters:

data - the data

Returns:

a copy of the data as an array of unsigned 16-bit values in most-to-least (big endian) byte order, represented as 32-bit int values to maintain as unsigned values, or null if data is null

decodeUnsigned

public static int[] decodeUnsigned(byte[] data,
                                   int start,
                                   int end)

Get raw data as unsigned 16-bit values.

Parameters:

data - the data

start - the starting offset with data, inclusive

end - the ending offset with data, exclusive

Returns:

a copy of the data as an array of unsigned 16-bit values in most-to-least (big endian) byte order, represented as 32-bit int values to maintain as unsigned values, or null if data is null

reverse

public static void reverse(byte[] data)

Reverse a byte array.

This modifies the contents of the array directly.

Parameters:

data - the data to reverse

encode16

public static void encode16(byte[] data,
                            int offset,
                            int value)

Encode a 16-bit value into a byte array.

Parameters:

data - the data array

offset - the offset within data to start populating

value - the value to populate