/*
*
*
* Copyright 1990-2007 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 only, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License version 2 for more details (a copy is
* included at /legal/license.txt).
*
* You should have received a copy of the GNU General Public License
* version 2 along with this work; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 or visit www.sun.com if you need additional
* information or have any questions.
*/
package com.sun.cldc.i18n.j2me;
import java.io.*;
/**
* Writer for UTF-8 encoded output streams. NOTE: The UTF-8 writer only
* supports UCS-2, or Unicode, to UTF-8 conversion. There is no support
* for UTF-16 encoded characters outside of the Basic Multilingual Plane
* (BMP). These are encoded in UTF-16 using previously reserved values
* between U+D800 and U+DFFF. Additionally, the UTF-8 writer does not
* support any character that requires 4 or more UTF-8 encoded bytes.
*/
public class UTF_8_Writer extends com.sun.cldc.i18n.StreamWriter {
/** pending high surrogate code unit, or zero */
protected int pendingSurrogate;
/** This value replaces invalid characters
* (that is, surrogates code units without a pair) */
static final private int replacementValue = 0x3f;
/**
* Write a portion of an array of characters.
*
* @param cbuf Array of characters
* @param off Offset from which to start writing characters
* @param len Number of characters to write
*
* @exception IOException If an I/O error occurs
*/
public void write(char cbuf[], int off, int len) throws IOException {
byte[] outputByte = new byte[4]; // Never more than 4 encoded bytes
int inputChar;
int outputSize;
int count = 0;
while (count < len) {
inputChar = 0xffff & cbuf[off + count];
if (0 != pendingSurrogate) {
if (0xdc00<=inputChar && inputChar<=0xdfff) {
//000u uuuu xxxx xxxx xxxx xxxx
//1101 10ww wwxx xxxx 1101 11xx xxxx xxxx
final int highHalf = (pendingSurrogate & 0x03ff) + 0x0040;
final int lowHalf = inputChar & 0x03ff;
inputChar = (highHalf << 10) | lowHalf;
} else {
// write replacement value instead of unpaired surrogate
outputByte[0] = replacementValue;
outputSize = 1;
out.write(outputByte, 0, outputSize);
}
pendingSurrogate = 0;
}
if (inputChar < 0x80) {
outputByte[0] = (byte)inputChar;
outputSize = 1;
} else if (inputChar < 0x800) {
outputByte[0] = (byte)(0xc0 | ((inputChar >> 6) & 0x1f));
outputByte[1] = (byte)(0x80 | (inputChar & 0x3f));
outputSize = 2;
} else if (0xd800<=inputChar && inputChar<=0xdbff) {
pendingSurrogate = inputChar;
outputSize = 0;
} else if (0xdc00<=inputChar && inputChar<=0xdfff) {
// unpaired surrogate
outputByte[0] = replacementValue;
outputSize = 1;
} else if (inputChar < 0x10000) {
outputByte[0] = (byte)(0xe0 | ((inputChar >> 12) & 0x0f));
outputByte[1] = (byte)(0x80 | ((inputChar >> 6) & 0x3f));
outputByte[2] = (byte)(0x80 | (inputChar & 0x3f));
outputSize = 3;
} else {
/* 21 bits: 1111 0xxx 10xx xxxx 10xx xxxx 10xx xxxx
* a aabb bbbb cccc ccdd dddd
*/
outputByte[0] = (byte)(0xf0 | ((inputChar >> 18) & 0x07));
outputByte[1] = (byte)(0x80 | ((inputChar >> 12) & 0x3f));
outputByte[2] = (byte)(0x80 | ((inputChar >> 6) & 0x3f));
outputByte[3] = (byte)(0x80 | (inputChar & 0x3f));
outputSize = 4;
}
out.write(outputByte, 0, outputSize);
count++;
}
}
/**
* Get the size in chars of an array of bytes.
*
* @param array Source buffer
* @param offset Offset at which to start counting characters
* @param length number of bytes to use for counting
*
* @return number of characters that would be converted
*/
public int sizeOf(char[] array, int offset, int length) {
int outputSize = 0;
int inputChar;
while (offset < length) {
inputChar = array[offset];
if (inputChar < 0x80) {
outputSize++;
} else if (inputChar < 0x800) {
outputSize += 2;
} else {
outputSize += 3;
}
offset++;
}
return outputSize;
}
/**
* Open the writer.
*
* @param outputStream
* @param encoding encoding
* @return the writer
* @throws UnsupportedEncodingException
*/
public Writer open(OutputStream outputStream, String encoding)
throws UnsupportedEncodingException {
pendingSurrogate = 0;
return super.open(outputStream,encoding);
}
/**
* Close the writer and the output stream.
*
* @throws IOException
*/
public void close() throws IOException {
if (0 != pendingSurrogate) {
// write replacement value instead of the unpaired surrogate
byte[] outputByte = new byte[1];
outputByte[0] = replacementValue;
out.write(outputByte, 0, 1);
}
pendingSurrogate = 0;
super.close();
}
// flush() can do nothing with pendingSurrogate because the surrogate
// contains only a portion of the character code, and the second half
// is still expected to arrive.
// public void flush() throws IOException { super.flush(); }
}
|
