org.jwat.common

Class UTF8

java.lang.Object

org.jwat.common.UTF8

public class UTF8
extends java.lang.Object

Small class to decode and encode UTF-8 characters. Decoding also keeps track of encoding errors. Processes one UTF-8 character at a time. The decoding method reports encoding validity in a field. Char. number range | UTF-8 octet sequence (hexadecimal) | (binary) --------------------+--------------------------------------------- 0000 0000-0000 007F | 0xxxxxxx 0000 0080-0000 07FF | 110xxxxx 10xxxxxx 0000 0800-0000 FFFF | 1110xxxx 10xxxxxx 10xxxxxx 0001 0000-0010 FFFF | 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx

Author:

nicl

Field Summary

Fields

Modifier and Type	Field and Description
boolean	bValidChar UTF-8 validity status on last read character.
byte[]	chars_read Bytes read in the decoding process.
int	utf8_c Complete or partial UTF-8 character, depending on conversion errors.

Constructor Summary

Constructors

Constructor and Description
UTF8()

Method Summary

Modifier and Type	Method and Description
int	readUtf8(int c, java.io.InputStream in) Given a character and an input stream returns the next decoded UTF-8 character.
int	writeUtf8(int c, java.io.OutputStream out) UTF-8 encodes a character and outputs in onto the stream.

Methods inherited from class java.lang.Object

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

Field Detail

utf8_c

public int utf8_c

Complete or partial UTF-8 character, depending on conversion errors.

chars_read

public byte[] chars_read

Bytes read in the decoding process.

bValidChar

public boolean bValidChar

UTF-8 validity status on last read character.

Constructor Detail

UTF8

public UTF8()

Method Detail

readUtf8

public int readUtf8(int c,
                    java.io.InputStream in)
             throws java.io.IOException

Given a character and an input stream returns the next decoded UTF-8 character. The encoded UTF-8 character is between 1 and 4 bytes long. In order to preserve the validity and character value, the character is returned by the method and its validity is available through the bValidChar {link #bValidChar} field.

Parameters:

c - initial character

in - input stream used to read extra UTF-8 encoded data

Returns:

UTF-8 character or -1

Throws:

java.io.IOException - if an I/O error occurs while reading

writeUtf8

public int writeUtf8(int c,
                     java.io.OutputStream out)
              throws java.io.IOException

UTF-8 encodes a character and outputs in onto the stream. Returns the number of bytes used to encode the character.

Parameters:

c - character to UTF-8 encode

out - UTF-8 output stream

Returns:

the number of bytes used to encode the character

Throws:

java.io.IOException - if an I/O error occurs while writing