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This module contains non-RDF library code and the common system runtime.
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.jena.atlas.io;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.Writer;
/** Output UTF-8 encoded data.
* This class implements the "Modified UTF8" encoding rules (null {@literal ->} C0 80)
* It will encode any 16 bit value.
* It can be used as a pure UTF-8 encoder.
*
* @see InStreamUTF8
*/
public final class OutStreamUTF8 extends Writer {
private OutputStream out;
public OutStreamUTF8(OutputStream out) {
// Buffer?
this.out = out;
}
@Override
public void write(char[] cbuf, int off, int len) throws IOException {
for ( int i = 0 ; i < len ; i++ )
write(cbuf[off + i]);
}
@Override
public void write(int ch) throws IOException {
output(out, ch);
}
@Override
public void write(char[] b) throws IOException {
write(b, 0, b.length);
}
@Override
public void write(String str) throws IOException {
write(str, 0, str.length());
}
@Override
public void write(String str, int idx, int len) throws IOException {
for ( int i = 0 ; i < len ; i++ )
write(str.charAt(idx + i));
}
public void output(int x) {
try {
output(out, x);
} catch (IOException ex) {
IO.exception(ex);
}
}
/** Return a byte array with the UTF-8 encoding of the integer */
public static byte[] encode(int ch) {
try ( ByteArrayOutputStream out = new ByteArrayOutputStream(8) ) {
output(out, ch);
return out.toByteArray();
} catch (IOException ex) {
IO.exception(ex);
return null;
}
}
/*
* Unicode ends at 0x10FFFF (1,114,112 code points)
* Bits
* 7 U+007F 1 to 127 0xxxxxxx
* 11 U+07FF 128 to 2,047 110xxxxx 10xxxxxx
* 16 U+FFFF 2,048 to 65,535 1110xxxx 10xxxxxx 10xxxxxx
* 21 U+1FFFFF 65,536 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
* 26 U+3FFFFFF 111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
* 31 U+7FFFFFFF 1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
*/
public static void output(OutputStream out, int ch) throws IOException {
if ( ch != 0 && ch <= 127 ) {
// 7 bits
out.write(ch);
return;
}
if ( ch == 0 ) {
// Modified UTF-8.
out.write(0xC0);
out.write(0x80);
return;
}
if ( ch <= 0x07FF ) {
// 11 bits : 110yyyyy 10xxxxxx
// int x1 = ( ((ch>>(11-5))&0x7) | 0xC0 ) ; outputBytes(out, x1, 2, ch) ;
// return ;
int x1 = (((ch >> (11 - 5)) & 0x01F) | 0xC0);
int x2 = ((ch & 0x3F) | 0x80);
out.write(x1);
out.write(x2);
return;
}
if ( ch <= 0xFFFF ) {
// 16 bits : 1110aaaa 10bbbbbb 10cccccc
// int x1 = ( ((ch>>(16-4))&0x7) | 0xE0 ) ; outputBytes(out, x1, 3, ch) ;
// return ;
int x1 = (((ch >> (16 - 4)) & 0x0F) | 0xE0);
int x2 = (((ch >> 6) & 0x3F) | 0x80);
int x3 = ((ch & 0x3F) | 0x80);
out.write(x1);
out.write(x2);
out.write(x3);
return;
}
// Unicode ends at 0x10FFFF
if ( ch <= 0x1FFFFF ) {
// 21 bits : 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
int x1 = (((ch >> (21 - 3)) & 0x7) | 0xF0);
outputBytes(out, x1, 4, ch);
return;
}
if ( ch <= 0x3FFFFFF ) {
// 26 bits : 111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
int x1 = (((ch >> (26 - 2)) & 0x3) | 0xF8);
outputBytes(out, x1, 5, ch);
return;
}
if ( ch <= 0x7FFFFFFF ) {
// 32 bits : 1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
int x1 = (((ch >> (32 - 1)) & 0x1) | 0xFC);
outputBytes(out, x1, 6, ch);
return;
}
}
/**
* Write a total of {@code byteLength bytes}; first, value {@code x1}, then the
* remaining bytes of {@code ch}.
*
*
* byte x1
* 10xxxxxx
* 10xxxxxx
* ...
*
*/
private static void outputBytes(OutputStream out, int x1, int byteLength, int ch) throws IOException {
// ByteLength = 3 => 2 byteLength => shift=6 and shift=0
out.write(x1);
byteLength--; // remaining bytes
for ( int i = 0 ; i < byteLength ; i++ ) {
// 6 Bits, loop from high to low
int shift = 6 * (byteLength - i - 1);
int x = (ch >> shift) & 0x3F;
x = x | 0x80; // 10xxxxxx
out.write(x);
}
}
@Override
public void flush() throws IOException {
out.flush();
}
@Override
public void close() throws IOException {
out.close();
}
}