/
Utf8HttpWriter.java
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/
Utf8HttpWriter.java
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//
// ========================================================================
// Copyright (c) 1995-2019 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
//
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
//
package org.eclipse.jetty.server;
import java.io.IOException;
/**
* OutputWriter.
* A writer that can wrap a {@link HttpOutput} stream and provide
* character encodings.
*
* The UTF-8 encoding is done by this class and no additional
* buffers or Writers are used.
* The UTF-8 code was inspired by http://javolution.org
*/
public class Utf8HttpWriter extends HttpWriter
{
int _surrogate = 0;
public Utf8HttpWriter(HttpOutput out)
{
super(out);
}
@Override
public void write(char[] s, int offset, int length) throws IOException
{
HttpOutput out = _out;
while (length > 0)
{
_bytes.reset();
int chars = Math.min(length, MAX_OUTPUT_CHARS);
byte[] buffer = _bytes.getBuf();
int bytes = _bytes.getCount();
if (bytes + chars > buffer.length)
chars = buffer.length - bytes;
for (int i = 0; i < chars; i++)
{
int code = s[offset + i];
// Do we already have a surrogate?
if (_surrogate == 0)
{
// No - is this char code a surrogate?
if (Character.isHighSurrogate((char)code))
{
_surrogate = code; // UCS-?
continue;
}
}
// else handle a low surrogate
else if (Character.isLowSurrogate((char)code))
{
code = Character.toCodePoint((char)_surrogate, (char)code); // UCS-4
}
// else UCS-2
else
{
code = _surrogate; // UCS-2
_surrogate = 0; // USED
i--;
}
if ((code & 0xffffff80) == 0)
{
// 1b
if (bytes >= buffer.length)
{
chars = i;
break;
}
buffer[bytes++] = (byte)(code);
}
else
{
if ((code & 0xfffff800) == 0)
{
// 2b
if (bytes + 2 > buffer.length)
{
chars = i;
break;
}
buffer[bytes++] = (byte)(0xc0 | (code >> 6));
buffer[bytes++] = (byte)(0x80 | (code & 0x3f));
}
else if ((code & 0xffff0000) == 0)
{
// 3b
if (bytes + 3 > buffer.length)
{
chars = i;
break;
}
buffer[bytes++] = (byte)(0xe0 | (code >> 12));
buffer[bytes++] = (byte)(0x80 | ((code >> 6) & 0x3f));
buffer[bytes++] = (byte)(0x80 | (code & 0x3f));
}
else if ((code & 0xff200000) == 0)
{
// 4b
if (bytes + 4 > buffer.length)
{
chars = i;
break;
}
buffer[bytes++] = (byte)(0xf0 | (code >> 18));
buffer[bytes++] = (byte)(0x80 | ((code >> 12) & 0x3f));
buffer[bytes++] = (byte)(0x80 | ((code >> 6) & 0x3f));
buffer[bytes++] = (byte)(0x80 | (code & 0x3f));
}
else if ((code & 0xf4000000) == 0)
{
// 5b
if (bytes + 5 > buffer.length)
{
chars = i;
break;
}
buffer[bytes++] = (byte)(0xf8 | (code >> 24));
buffer[bytes++] = (byte)(0x80 | ((code >> 18) & 0x3f));
buffer[bytes++] = (byte)(0x80 | ((code >> 12) & 0x3f));
buffer[bytes++] = (byte)(0x80 | ((code >> 6) & 0x3f));
buffer[bytes++] = (byte)(0x80 | (code & 0x3f));
}
else if ((code & 0x80000000) == 0)
{
// 6b
if (bytes + 6 > buffer.length)
{
chars = i;
break;
}
buffer[bytes++] = (byte)(0xfc | (code >> 30));
buffer[bytes++] = (byte)(0x80 | ((code >> 24) & 0x3f));
buffer[bytes++] = (byte)(0x80 | ((code >> 18) & 0x3f));
buffer[bytes++] = (byte)(0x80 | ((code >> 12) & 0x3f));
buffer[bytes++] = (byte)(0x80 | ((code >> 6) & 0x3f));
buffer[bytes++] = (byte)(0x80 | (code & 0x3f));
}
else
{
buffer[bytes++] = (byte)('?');
}
_surrogate = 0; // USED
if (bytes == buffer.length)
{
chars = i + 1;
break;
}
}
}
_bytes.setCount(bytes);
_bytes.writeTo(out);
length -= chars;
offset += chars;
}
}
}