/*
*
*
* 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.ukit.jaxp;
import java.io.Reader;
import java.io.InputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
/**
* UTF-8 transformed UCS-2 character stream reader.
*
* This reader converts UTF-8 transformed UCS-2 characters to Java characters.
* The UCS-2 subset of UTF-8 transformation is described in RFC-2279 #2
* "UTF-8 definition":
* 0000 0000-0000 007F 0xxxxxxx
* 0000 0080-0000 07FF 110xxxxx 10xxxxxx
* 0000 0800-0000 FFFF 1110xxxx 10xxxxxx 10xxxxxx
*
* This reader will return incorrect last character on broken UTF-8 stream.
*/
public class ReaderUTF8
extends Reader
{
private InputStream is;
/**
* Constructor.
*
* @param is A byte input stream.
*/
public ReaderUTF8(InputStream is)
{
this.is = is;
}
/**
* Reads characters into a portion of an array.
*
* @param cbuf Destination buffer.
* @param off Offset at which to start storing characters.
* @param len Maximum number of characters to read.
* @exception IOException If any IO errors occur.
* @exception UnsupportedEncodingException If UCS-4 character occur in the stream.
*/
public int read(char[] cbuf, int off, int len)
throws IOException
{
int num = 0;
int val;
while (num < len) {
if ((val = is.read()) < 0)
return (num != 0)? num: -1;
switch (val & 0xf0) {
case 0xc0:
case 0xd0:
cbuf[off++] = (char)(((val & 0x1f) << 6) | (is.read() & 0x3f));
break;
case 0xe0:
cbuf[off++] = (char)(((val & 0x0f) << 12) |
((is.read() & 0x3f) << 6) | (is.read() & 0x3f));
break;
case 0xf0: // UCS-4 character
throw new UnsupportedEncodingException();
default:
cbuf[off++] = (char)val;
break;
}
num++;
}
return num;
}
/**
* Reads a single character.
*
* @return The character read, as an integer in the range 0 to 65535
* (0x00-0xffff), or -1 if the end of the stream has been reached.
* @exception IOException If any IO errors occur.
* @exception UnsupportedEncodingException If UCS-4 character occur in the stream.
*/
public int read()
throws IOException
{
int val;
if ((val = is.read()) < 0)
return -1;
switch (val & 0xf0) {
case 0xc0:
case 0xd0:
val = ((val & 0x1f) << 6) | (is.read() & 0x3f);
break;
case 0xe0:
val = ((val & 0x0f) << 12) |
((is.read() & 0x3f) << 6) | (is.read() & 0x3f);
break;
case 0xf0: // UCS-4 character
throw new UnsupportedEncodingException();
default:
break;
}
return val;
}
/**
* Closes the stream.
*
* @exception IOException If any IO errors occur.
*/
public void close()
throws IOException
{
is.close();
}
}
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