Package com.globalmentor.io

Class UTF8

java.lang.Object

com.globalmentor.io.UTF8

public class UTF8
extends java.lang.Object

Constants and methods for working with the UTF-8 encoding.

Author:

Garret Wilson

See Also:

RFC 3629: UTF-8, a transformation format of ISO 10646, Wikipedia: UTF-8, Sun: What Is UTF-8 And Why Is It Important?, UTF-8 Test

Field Summary

Fields

Modifier and Type	Field	Description
static int	MAX_ENCODED_BYTE_COUNT_LENGTH	The maximum number of octets used to encoded a character in UTF-8.
static int	MAX_ENCODED_BYTE_COUNT1	The largest code point value that can be encoded in one byte.
static int	MAX_ENCODED_BYTE_COUNT2	The largest code point value that can be encoded in two bytes.
static int	MAX_ENCODED_BYTE_COUNT3	The largest code point value that can be encoded in three bytes.

Constructor Summary

Constructors

Constructor	Description
UTF8()

Method Summary

Modifier and Type	Method	Description
static int	getEncodedByteCountForCodePoint(int c)	Determines how many bytes are needed to encode a single character in UTF-8.
static int	getEncodedByteCountFromInitialByte(byte initialByte)	Determines how many bytes are used to encoded a sequence based on its first encoded byte.
static int	getEncodedByteCountFromInitialOctet(int initialOctet)	Determines how many bytes are used to encoded a sequence based on its first encoded octet.

Methods inherited from class java.lang.Object

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

Field Detail

MAX_ENCODED_BYTE_COUNT1

public static final int MAX_ENCODED_BYTE_COUNT1

The largest code point value that can be encoded in one byte.

See Also:

Constant Field Values

MAX_ENCODED_BYTE_COUNT2

public static final int MAX_ENCODED_BYTE_COUNT2

The largest code point value that can be encoded in two bytes.

See Also:

Constant Field Values

MAX_ENCODED_BYTE_COUNT3

public static final int MAX_ENCODED_BYTE_COUNT3

The largest code point value that can be encoded in three bytes.

See Also:

Constant Field Values

MAX_ENCODED_BYTE_COUNT_LENGTH

public static final int MAX_ENCODED_BYTE_COUNT_LENGTH

The maximum number of octets used to encoded a character in UTF-8.

See Also:

Constant Field Values

Constructor Detail

UTF8

public UTF8()

Method Detail

getEncodedByteCountForCodePoint

public static int getEncodedByteCountForCodePoint(int c)

Determines how many bytes are needed to encode a single character in UTF-8.

Parameters:

c - The character to encode.

Returns:

The minimum number of bytes needed to encode a single character.

getEncodedByteCountFromInitialByte

public static int getEncodedByteCountFromInitialByte(byte initialByte)

Determines how many bytes are used to encoded a sequence based on its first encoded byte.

Parameters:

initialByte - The value of the first byte (which in Java may be a negative number, as bytes are signed) in a UTF-8 sequence.

Returns:

The number of octets to expect in the sequence beginning with the given byte.

Throws:

java.lang.IllegalArgumentException - if the given value is not a valid initial octet of UTF-8.

See Also:

getEncodedByteCountFromInitialOctet(int)

getEncodedByteCountFromInitialOctet

public static int getEncodedByteCountFromInitialOctet(int initialOctet)

Determines how many bytes are used to encoded a sequence based on its first encoded octet.

Parameters:

initialOctet - The value of the first octet in a UTF-8 sequence.

Returns:

The number of octets to expect in the sequence beginning with the given octet.

Throws:

java.lang.IllegalArgumentException - if the given value is not a valid initial octet of UTF-8.