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/*
* 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.tomcat.util.buf;
import java.nio.BufferUnderflowException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
public class CharsetUtil {
private CharsetUtil() {
// Utility class. Hide default constructor.
}
public static boolean isAsciiSuperset(Charset charset) {
// Bytes 0x00 to 0x7F must decode to the first 128 Unicode characters
CharsetDecoder decoder = charset.newDecoder();
ByteBuffer inBytes = ByteBuffer.allocate(1);
CharBuffer outChars;
for (int i = 0; i < 128; i++) {
inBytes.clear();
inBytes.put((byte) i);
inBytes.flip();
try {
outChars = decoder.decode(inBytes);
} catch (CharacterCodingException e) {
return false;
}
try {
if (outChars.get() != i) {
return false;
}
} catch (BufferUnderflowException e) {
return false;
}
}
return true;
}
}
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