Package java.nio.charset

Class ModifiedUtf8

java.lang.Object

java.nio.charset.ModifiedUtf8

public class ModifiedUtf8
extends Object

Encoding and decoding methods for Modified UTF-8

Modified UTF-8 is a simple variation of UTF-8 in which is encoded as 0xc0 0x80 . This avoids the presence of bytes 0 in the output.

Constructor Summary

Constructors

Constructor	Description
ModifiedUtf8()

Method Summary

Modifier and Type	Method	Description
static long	countBytes(String s, boolean shortLength)	Count the number of bytes in the modified UTF-8 representation of s.
static String	decode(byte[] in, char[] out, int offset, int length)	Decodes length utf-8 bytes from in starting at offset offset to out,
static void	encode(byte[] dst, int offset, String s)	Encode s into dst starting at offset offset.
static byte[]	encode(String s)	Encodes s into a buffer with the following format:

Methods inherited from class java.lang.Object

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

Constructor Detail

ModifiedUtf8

public ModifiedUtf8()

Method Detail

countBytes

public static long countBytes(String s,
                              boolean shortLength)
                       throws UTFDataFormatException

Count the number of bytes in the modified UTF-8 representation of s.

Additionally, if shortLength is true, throw a UTFDataFormatException if the size cannot be presented in an (unsigned) java short.

Throws:

UTFDataFormatException

encode

public static void encode(byte[] dst,
                          int offset,
                          String s)

Encode s into dst starting at offset offset.

The output buffer is guaranteed to have enough space.

encode

public static byte[] encode(String s)
                     throws UTFDataFormatException

Encodes s into a buffer with the following format:

- the first two bytes of the buffer are the length of the modified-utf8 output (as a big endian short. A UTFDataFormatException is thrown if the encoded size cannot be represented as a short.

- the remainder of the buffer contains the modified-utf8 output (equivalent to encode(buf, 2, s)).

Throws:

UTFDataFormatException

decode

public static String decode(byte[] in,
                            char[] out,
                            int offset,
                            int length)
                     throws UTFDataFormatException

Decodes length utf-8 bytes from in starting at offset offset to out,

A maximum of length chars are written to the output starting at offset 0. out is assumed to have enough space for the output (a standard ArrayIndexOutOfBoundsException is thrown otherwise).

If a ‘0’ byte is encountered, it is converted to U+0000.

Throws:

UTFDataFormatException